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Message from the Editor-in-Chief |
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Thomas Ertl
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Pages: x-x |
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doi>10.1109/TVCG.2010.178 |
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Preface |
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Jean-Daniel Fekete,
Frank van Ham,
Raghu Machiraju,
Torsten Moller,
Hanspeter Pfister
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Pages: xi-xx |
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doi>10.1109/TVCG.2010.188 |
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In Memoriam: Illuminating Our Paths - James (Jim) Joseph Thomas |
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David S Ebert,
John Dill,
David J. Kasik
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Page: xxi |
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doi>10.1109/TVCG.2010.167 |
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The 2010 Visualization Career Award |
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Page: xxii |
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doi>10.1109/TVCG.2010.203 |
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The 2010 Visualization Techinal Achievement Award |
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Page: xxiii |
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doi>10.1109/TVCG.2010.204 |
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VisWeek Keynote Address |
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Mary Hegarty
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Page: xxiv |
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doi>10.1109/TVCG.2010.220 |
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Necklace Maps |
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authro Speckmann,
Kevin Verbeek
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Pages: 881-889 |
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doi>10.1109/TVCG.2010.180 |
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Statistical
data associated with geographic regions is nowadays globally available
in large amounts and hence automated methods to visually display these
data are in high demand. There are several well-established thematic map
types for quantitative ...
Statistical
data associated with geographic regions is nowadays globally available
in large amounts and hence automated methods to visually display these
data are in high demand. There are several well-established thematic map
types for quantitative data on the ratio-scale associated with regions:
choropleth maps, cartograms, and proportional symbol maps. However, all
these maps suffer from limitations, especially if large data values are
associated with small regions. To overcome these limitations, we
propose a novel type of quantitative thematic map, the necklace map. In a
necklace map, the regions of the underlying two-dimensional map are
projected onto intervals on a one-dimensional curve (the necklace) that
surrounds the map regions. Symbols are scaled such that their area
corresponds to the data of their region and placed without overlap
inside the corresponding interval on the necklace. Necklace maps appear
clear and uncluttered and allow for comparatively large symbol sizes.
They visualize data sets well which are not proportional to region
sizes. The linear ordering of the symbols along the necklace facilitates
an easy comparison of symbol sizes. One map can contain several nested
or disjoint necklaces to visualize clustered data. The advantages of
necklace maps come at a price: the association between a symbol and its
region is weaker than with other types of maps. Interactivity can help
to strengthen this association if necessary. We present an automated
approach to generate necklace maps which allows the user to
interactively control the final symbol placement. We validate our
approach with experiments using various data sets and maps. expand
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Rethinking Map Legends with Visualization |
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Jason Dykes,
Jo Wood,
Aidan Slingsby
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Pages: 890-899 |
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doi>10.1109/TVCG.2010.191 |
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This
design paper presents new guidance for creating map legends in a
dynamic environment. Our contribution is a set ofguidelines for legend
design in a visualization context and a series of illustrative themes
through which they may be expressed. Theseare ...
This
design paper presents new guidance for creating map legends in a
dynamic environment. Our contribution is a set ofguidelines for legend
design in a visualization context and a series of illustrative themes
through which they may be expressed. Theseare demonstrated in an
applications context through interactive software prototypes. The
guidelines are derived from cartographicliterature and in liaison with
EDINA who provide digital mapping services for UK tertiary education.
They enhance approaches tolegend design that have evolved for static
media with visualization by considering: selection, layout, symbols,
position, dynamismand design and process. Broad visualization legend
themes include: The Ground Truth Legend, The Legend as Statistical
Graphicand The Map is the Legend. Together, these concepts enable us to
augment legends with dynamic properties that address specificneeds,
rethink their nature and role and contribute to a wider re-evaluation of
maps as artifacts of usage rather than statements offact. EDINA has
acquired funding to enhance their clients with visualization legends
that use these concepts as a consequence ofthis work. The guidance
applies to the design of a wide range of legends and keys used in
cartography and information visualization. expand
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SignalLens: Focus+Context Applied to Electronic Time Series |
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Robert Kincaid
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Pages: 900-907 |
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doi>10.1109/TVCG.2010.193 |
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Electronic
test and measurement systems are becoming increasingly sophisticated in
order to match the increased complexity and ultra-high speed of the
devices under test. A key feature in many such instruments is a vastly
increased capacity for storage ...
Electronic
test and measurement systems are becoming increasingly sophisticated in
order to match the increased complexity and ultra-high speed of the
devices under test. A key feature in many such instruments is a vastly
increased capacity for storage of digital signals. Storage of $10^9$
time points or more is now possible. At the same time, the typical
screens on such measurement devices are relatively small. Therefore,
these instruments can only render an extremely small fraction of the
complete signal at any time. SignalLens uses a Focus+Context approach to
provide a means of navigating to and inspecting low-level signal
details in the context of the entire signal trace. This approach
provides a compact visualization suitable for embedding into the small
displays typically provided by electronic measurement instruments. We
further augment this display with computed tracks which display
time-aligned computed properties of the signal. By combining and
filtering these computed tracks it is possible to easily and quickly
find computationally detected features in the data which are often
obscured by the visual compression required to render the large data
sets on a small screen. Further, these tracks can be viewed in the
context of the entire signal trace as well as visible high-level signal
features. Several examples using real-world electronic measurement data
are presented, which demonstrate typical use cases and the effectiveness
of the design. expand
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Comparative Analysis of Multidimensional, Quantitative Data |
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Miriah Meyer,
Tamara Munzner,
Angela DePace,
Hanspeter Pfister
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Pages: 908-917 |
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doi>10.1109/TVCG.2010.137 |
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Cells
in an organism share the same genetic information in their DNA, but
have very different forms and behavior becauseof the selective
expression of subsets of their genes. The widely used approach of
measuring gene expression over time froma tissue ...
Cells
in an organism share the same genetic information in their DNA, but
have very different forms and behavior becauseof the selective
expression of subsets of their genes. The widely used approach of
measuring gene expression over time froma tissue sample using techniques
such as microarrays or sequencing do not provide information about the
spatial position withinthe tissue where these genes are expressed. In
contrast, we are working with biologists who use techniques that measure
geneexpression in every individual cell of entire fruitfly embryos over
an hour of their development, and do so for multiple
closely-relatedsubspecies of Drosophila. These scientists are faced with
the challenge of integrating temporal gene expression data with the
spatiallocation of cells and, moreover, comparing this data across
multiple related species. We have worked with these biologists overthe
past two years to develop MulteeSum, a visualization system that
supports inspection and curation of data sets showing geneexpression
over time, in conjunction with the spatial location of the cells where
the genes are expressed — it is the first tool tosupport comparisons
across multiple such data sets. MulteeSum is part of a general and
flexible framework we developed with ourcollaborators that is built
around multiple summaries for each cell, allowing the biologists to
explore the results of computations thatmix spatial information, gene
expression measurements over time, and data from multiple related
species or organisms. We justifyour design decisions based on specific
descriptions of the analysis needs of our collaborators, and provide
anecdotal evidence of theefficacy of MulteeSum through a series of case
studies. expand
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Gremlin: An Interactive Visualization Model for Analyzing Genomic Rearrangements |
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Trevor O'Brien,
Anna Ritz,
Benjamin Raphael,
David Laidlaw
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Pages: 918-926 |
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doi>10.1109/TVCG.2010.163 |
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In
this work we present, apply, and evaluate a novel, interactive
visualization model for comparative analysis of structural variants and
rearrangements in human and cancer genomes, with emphasis on data
integration and uncertainty visualization. To ...
In
this work we present, apply, and evaluate a novel, interactive
visualization model for comparative analysis of structural variants and
rearrangements in human and cancer genomes, with emphasis on data
integration and uncertainty visualization. To support both global trend
analysis and local feature detection, this model enables explorations
continuously scaled from the high-level, complete genome perspective,
down to the low-level, structural rearrangement view, while preserving
global context at all times. We have implemented these techniques in
Gremlin, a genomic rearrangement explorer with multi-scale, linked
interactions, which we apply to four human cancer genome data sets for
evaluation. Using an insight-based evaluation methodology, we compare
Gremlin to Circos, the state-of-the-art in genomic rearrangement
visualization, through a small user study with computational biologists
working in rearrangement analysis. Results from user study evaluations
demonstrate that this visualization model enables more total insights,
more insights per minute, and more complex insights than the current
state-of-the-art for visual analysis and exploration of genome
rearrangements. expand
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Graphical Perception of Multiple Time Series |
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Waqas Javed,
Bryan McDonnel,
Niklas Elmqvist
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Pages: 927-934 |
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doi>10.1109/TVCG.2010.162 |
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Line
graphs have been the visualization of choice for temporal data ever
since the days of William Playfair (1759-1823), but realistic temporal
analysis tasks often include multiple simultaneous time series.In this
work, we explore user performance for ...
Line
graphs have been the visualization of choice for temporal data ever
since the days of William Playfair (1759-1823), but realistic temporal
analysis tasks often include multiple simultaneous time series.In this
work, we explore user performance for comparison, slope, and
discrimination tasks for different line graph techniques involving
multiple time series.Our results show that techniques that create
separate charts for each time series--such as small multiples and
horizon graphs--are generally more efficient for comparisons across time
series with a large visual span.On the other hand, shared-space
techniques--like standard line graphs--are typically more efficient for
comparisons over smaller visual spans where the impact of overlap and
clutter is reduced. expand
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Uncovering Strengths and Weaknesses of Radial Visualizations---an Empirical Approach |
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Stephan Diehl,
Fabian Beck,
Michael Burch
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Pages: 935-942 |
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doi>10.1109/TVCG.2010.209 |
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Radial
visualizations play an important role in the information visualization
community. But the decision to choose a radial coordinate system is
rather based on intuition than on scientific foundations. The empirical
approach presented in this paper ...
Radial
visualizations play an important role in the information visualization
community. But the decision to choose a radial coordinate system is
rather based on intuition than on scientific foundations. The empirical
approach presented in this paper aims at uncovering strengths and
weaknesses of radial visualizations by comparing them to equivalent ones
in Cartesian coordinate systems. We identified memorizing positions of
visual elements as a generic task when working with visualizations. A
first study with 674 participants provides a broad data spectrum for
exploring differences between the two visualization types. A second,
complementing study with fewer participants focuses on further questions
raised by the first study. Our findings document that Cartesian
visualizations tend to outperform their radial counterparts especially
with respect to answer times. Nonetheless, radial visualization seem to
be more appropriate for focusing on a particular data dimension. expand
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How Information Visualization Novices Construct Visualizations |
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Lars Grammel,
Melanie Tory,
Margaret-Anne Storey
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Pages: 943-952 |
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doi>10.1109/TVCG.2010.164 |
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It
remains challenging for information visualization novices to rapidly
construct visualizations during exploratory data analysis. We conducted
an exploratory laboratory study in which information visualization
novices explored fictitious sales data ...
It
remains challenging for information visualization novices to rapidly
construct visualizations during exploratory data analysis. We conducted
an exploratory laboratory study in which information visualization
novices explored fictitious sales data by communicating visualization
specifications to a human mediator, who rapidly constructed the
visualizations using commercial visualization software. We found that
three activities were central to the iterative visualization
construction process: data attribute selection, visual template
selection, and visual mapping specification. The major barriers faced by
the participants were translating questions into data attributes,
designing visual mappings, and interpreting the visualizations. Partial
specification was common, and the participants used simple heuristics
and preferred visualizations they were already familiar with, such as
bar, line and pie charts. We derived abstract models from our
observations that describe barriers in the data exploration process and
uncovered how information visualization novices think about
visualization specifications. Our findings support the need for tools
that suggest potential visualizations and support iterative refinement,
that provide explanations and help with learning, and that are tightly
integrated into tool support for the overall visual analytics process. expand
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eSeeTrack—Visualizing Sequential Fixation Patterns |
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Hoi Ying Tsang,
Melanie Tory,
Colin Swindells
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Pages: 953-962 |
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doi>10.1109/TVCG.2010.149 |
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We
introduce eSeeTrack, an eye-tracking visualization prototype that
facilitates exploration and comparison of sequential gaze orderings in a
static or a dynamic scene. It extends current eye-tracking data
visualizations by extracting patterns of sequential ...
We
introduce eSeeTrack, an eye-tracking visualization prototype that
facilitates exploration and comparison of sequential gaze orderings in a
static or a dynamic scene. It extends current eye-tracking data
visualizations by extracting patterns of sequential gaze orderings,
displaying these patterns in a way that does not depend on the number of
fixations on a scene, and enabling users to compare patterns from two
or more sets of eye-gaze data. Extracting such patterns was very
difficult with previous visualization techniques. eSeeTrack combines a
timeline and a tree-structured visual representation to embody three
aspects of eye-tracking data that users are interested in: duration,
frequency and orderings of fixations. We demonstrate the usefulness of
eSeeTrack via two case studies on surgical simulation and retail store
chain data. We found that eSeeTrack allows ordering of fixations to be
rapidly queried, explored and compared. Furthermore, our tool provides
an effective and efficient mechanism to determine pattern outliers. This
approach can be effective for behavior analysis in a variety of domains
that are described at the end of this paper. expand
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Evaluating the impact of task demands and block resolution on the effectiveness of pixel-based visualization |
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Rita Borgo,
Karl Proctor,
Min Chen,
Heike Janicke,
Tavi Murray,
Ian Thornton
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Pages: 963-972 |
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doi>10.1109/TVCG.2010.150 |
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Pixel-based
visualization is a popular method of conveying large amounts of
numerical data graphically. Application scenarios include business and
finance, bioinformatics and remote sensing. In this work, we examined
how the usability of such visual ...
Pixel-based
visualization is a popular method of conveying large amounts of
numerical data graphically. Application scenarios include business and
finance, bioinformatics and remote sensing. In this work, we examined
how the usability of such visual representations varied across different
tasks and block resolutions. The main stimuli consisted of temporal
pixel-based visualization with a white-red color map, simulating monthly
temperature variation over a six-year period. In the first study, we
included 5 separate tasks to exert different perceptual loads. We found
that performance varied considerably as a function of task, ranging from
75% correct in low-load tasks to below 40% in high-load tasks. There
was a small but consistent effect of resolution, with the uniform patch
improving performance by around 6% relative to higher block resolution.
In the second user study, we focused on a high-load task for evaluating
month-to-month changes across different regions of the temperature
range. We tested both CIE L*u*v* and RGB color spaces. We found that the
nature of the change-evaluation errors related directly to the distance
between the compared regions in the mapped color space. We were able to
reduce such errors by using multiple color bands for the same data
range. In a final study, we examined more fully the influence of block
resolution on performance, and found block resolution had a limited
impact on the effectiveness of pixel-based visualization. expand
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Graphical inference for infovis |
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Hadley Wickham,
Dianne Cook,
Heike Hofmann,
Andreas Buja
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Pages: 973-979 |
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doi>10.1109/TVCG.2010.161 |
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How
do we know if what we see is really there? When visualizing data, how
do we avoid falling into the trap of apophenia where we see patterns in
random noise? Traditionally, infovis has been concerned with discovering
new relationships, and statistics ...
How
do we know if what we see is really there? When visualizing data, how
do we avoid falling into the trap of apophenia where we see patterns in
random noise? Traditionally, infovis has been concerned with discovering
new relationships, and statistics with preventing spurious
relationships from being reported. Wepull these opposing poles closer
with two new techniques for rigorous statistical inference of visual
discoveries. The "Rorschach" helps the analyst calibrate their
understanding of uncertainty and "line-up" provides a protocol for
assessing the significance of visual discoveries, protecting against the
discovery of spurious structure. expand
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Matching Visual Saliency to Confidence in Plots of Uncertain Data |
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David Feng,
Lester Kwock,
Yueh Lee,
Russell Taylor
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Pages: 980-989 |
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doi>10.1109/TVCG.2010.176 |
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Conveying
data uncertainty in visualizations is crucial for preventing viewers
from drawing conclusions based on untrustworthy data points. This paper
proposes a methodology for efficiently generating density plots of
uncertain multivariate data sets ...
Conveying
data uncertainty in visualizations is crucial for preventing viewers
from drawing conclusions based on untrustworthy data points. This paper
proposes a methodology for efficiently generating density plots of
uncertain multivariate data sets that draws viewers to preattentively
identify values of high certainty while not calling attention to
uncertain values. We demonstrate how to augment scatter plots and
parallel coordinates plots to incorporate statistically modeled
uncertainty and show how to integrate them with existing multivariate
analysis techniques, including outlier detection and interactive
brushing. Computing high quality density plots can be expensive for
large data sets, so we also describe a probabilistic plotting technique
that summarizes the data without requiring explicit density plot
computation. These techniques have been useful for identifying brain
tumors in multivariate magnetic resonance spectroscopy data and we
describe how to extend them to visualize ensemble data sets. expand
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Perceptual Guidelines for Creating Rectangular Treemaps |
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Nicholas Kong,
Jeffrey Heer,
Maneesh Agrawala
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Pages: 990-998 |
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doi>10.1109/TVCG.2010.186 |
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Treemaps
are space-filling visualizations that make efficient use of limited
display space to depict large amounts of hierarchical data. Creating
perceptually effective treemaps requires carefully managing a number of
design parameters including the ...
Treemaps
are space-filling visualizations that make efficient use of limited
display space to depict large amounts of hierarchical data. Creating
perceptually effective treemaps requires carefully managing a number of
design parameters including the aspect ratio and luminance of
rectangles.Moreover, treemaps encode values using area, which has been
found to be less accurate than judgments of other visual encodings, such
as length. We conduct a series of controlled experiments aimed at
producing a set of design guidelines for creating effective rectangular
treemaps. We find no evidence that luminance affects area judgments, but
observe that aspect ratio does have an effect. Specifically, we find
that the accuracy of area comparisons suffers when the compared
rectangles have extreme aspect ratios or when both are squares. Contrary
to common assumptions, the optimal distribution of rectangle aspect
ratios within a treemap should include non-squares, but should avoid
extremes. We then compare treemaps with hierarchical bar chart displays
to identify the data densities at which length-encoded bar charts become
less effective than area-encoded treemaps. We report the transition
points at which treemaps exhibit judgment accuracy on par with bar
charts for both leaf and non-leaf tree nodes. We also find that even at
relatively low data densities treemaps result in faster comparisons than
bar charts. Based on these results, we present a set of guidelines for
the effective use of treemaps and suggest alternate approaches for
treemap layout. expand
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Mental Models, Visual Reasoning and Interaction in Information Visualization: A Top-down Perspective |
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Zhicheng Liu,
John Stasko
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Pages: 999-1008 |
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doi>10.1109/TVCG.2010.177 |
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Although
previous research has suggested that examining the interplay between
internal and external representations can benefit our understanding of
the role of information visualization (InfoVis) in human cognitive
activities, there has been little ...
Although
previous research has suggested that examining the interplay between
internal and external representations can benefit our understanding of
the role of information visualization (InfoVis) in human cognitive
activities, there has been little work detailing the nature of internal
representations, the relationship between internal and external
representations and how interaction is related to these representations.
In this paper, we identify and illustrate a specific kind of internal
representation, mental models, and outline the high-level relationships
between mental models and external visualizations. We present a top-down
perspective of reasoning as model construction and simulation, and
discuss the role of visualization in model based reasoning. From this
perspective, interaction can be understood as active modeling for three
primary purposes: external anchoring, information foraging, and
cognitive offloading. Finally we discuss the implications of our
approach for design, evaluation and theory development expand
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Laws of Attraction: From Perceptual Forces to Conceptual Similarity |
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Caroline Ziemkiewicz,
Robert Kosara
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Pages: 1009-1016 |
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doi>10.1109/TVCG.2010.174 |
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Many
of the pressing questions in information visualization deal with how
exactly a user reads a collection of visual marks as information about
relationships between entities. Previous research has suggested that
people see parts of a visualization ...
Many
of the pressing questions in information visualization deal with how
exactly a user reads a collection of visual marks as information about
relationships between entities. Previous research has suggested that
people see parts of a visualization as objects, and may metaphorically
interpret apparent physical relationships between these objects as
suggestive of data relationships. We explored this hypothesis in detail
in a series of user experiments. Inspired by the concept of implied
dynamics in psychology, we first studied whether perceived gravity
acting on a mark in a scatterplot can lead to errors in a participant's
recall of the mark's position. The results of this study suggested that
such position errors exist, but may be more strongly influenced by
attraction between marks. We hypothesized that such apparent attraction
may be influenced by elements used to suggest relationship between
objects, such as connecting lines, grouping elements, and visual
similarity. We further studied what visual elements are most likely to
cause this attraction effect, and whether the elements that best
predicted attraction errors were also those which suggested conceptual
relationships most strongly. Our findings show a correlation between
attraction errors and intuitions about relatedness, pointing towards a
possible mechanism by which the perception of visual marks becomes an
interpretation of data relationships. expand
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Pargnostics: Screen-Space Metrics for Parallel Coordinates |
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Aritra Dasgupta,
Robert Kosara
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Pages: 1017-1026 |
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doi>10.1109/TVCG.2010.184 |
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Interactive
visualization requires the translation of data into a screen space of
limited resolution. While currently ignored by most visualization
models, this translation entails a loss of information and the
introduction of a number of artifacts that ...
Interactive
visualization requires the translation of data into a screen space of
limited resolution. While currently ignored by most visualization
models, this translation entails a loss of information and the
introduction of a number of artifacts that can be useful, (e.g.,
aggregation, structures) or distracting (e.g., over-plotting, clutter)
for the analysis. This phenomenon is observed in parallel coordinates,
where overlapping lines between adjacent axes form distinct patterns,
representing the relation between variables they connect. However, even
for a small number of dimensions, the challenge is to effectively convey
the relationships for all combinations of dimensions. The size of the
dataset and a large number of dimensions only add to the complexity of
this problem.To address these issues, we propose Pargnostics, parallel
coordinates diagnostics, a model based on screen-space metrics that
quantify the different visual structures. Pargnostics metrics are
calculated for pairs of axes and take into account the resolution of the
display as well as potential axis inversions. Metrics include the
number of line crossings, crossing angles, convergence, overplotting,
etc. To construct a visualization view, the user can pick from a ranked
display showing pairs of coordinate axes and the structures between
them, or examine all possible combinations of axes at once in a matrix
display. Picking the best axes layout is an NP-complete problem in
general, but we provide a way of automatically optimizing the display
according to the user’s preferences based on our metrics and model. expand
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Comparative Analysis of Multidimensional, Quantitative Data |
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Alexander Lex,
Marc Streit,
Christian Partl,
Dieter Schmalstieg
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Pages: 1027-1035 |
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doi>10.1109/TVCG.2010.138 |
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When
analyzing multidimensional, quantitative data, the comparison of two or
more groups of dimensions is a commontask. Typical sources of such data
are experiments in biology, physics or engineering, which are conducted
in different configurationsand ...
When
analyzing multidimensional, quantitative data, the comparison of two or
more groups of dimensions is a commontask. Typical sources of such data
are experiments in biology, physics or engineering, which are conducted
in different configurationsand use replicates to ensure statistically
significant results. One common way to analyze this data is to filter it
using statistical methodsand then run clustering algorithms to group
similar values. The clustering results can be visualized using heat
maps, which showdifferences between groups as changes in color. However,
in cases where groups of dimensions have an a priori meaning, it is
notdesirable to cluster all dimensions combined, since a clustering
algorithm can fragment continuous blocks of records.
Furthermore,identifying relevant elements in heat maps becomes more
difficult as the number of dimensions increases. To aid in such
situations,we have developed Matchmaker, a visualization technique that
allows researchers to arbitrarily arrange and compare multiple groupsof
dimensions at the same time. We create separate groups of dimensions
which can be clustered individually, and place them in anarrangement of
heat maps reminiscent of parallel coordinates. To identify relations, we
render bundled curves and ribbons betweenrelated records in different
groups. We then allow interactive drill-downs using enlarged detail
views of the data, which enable in-depthcomparisons of clusters between
groups. To reduce visual clutter, we minimize crossings between the
views. This paper concludeswith two case studies. The first demonstrates
the value of our technique for the comparison of clustering algorithms.
In the second,biologists use our system to investigate why certain
strains of mice develop liver disease while others remain healthy,
informallyshowing the efficacy of our system when analyzing
multidimensional data containing distinct groups of dimensions. expand
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An Extension of Wilkinson’s Algorithm for Positioning Tick Labels on Axes |
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Justin Talbot,
Sharon Lin,
Pat Hanrahan
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Pages: 1036-1043 |
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doi>10.1109/TVCG.2010.130 |
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The
non-data components of a visualization, such as axes and legends, can
often be just as important as the data itself. They provide contextual
information essential to interpreting the data. In this paper, we
describe an automated system for choosing ...
The
non-data components of a visualization, such as axes and legends, can
often be just as important as the data itself. They provide contextual
information essential to interpreting the data. In this paper, we
describe an automated system for choosing positions and labels for axis
tick marks. Our system extends Wilkinson’s optimization-based labeling
approach to create a more robust, full-featured axis labeler. We define
an expanded space of axis labelings by automatically generating
additional nice numbers as needed and by permitting the extreme labels
to occur inside the data range. These changes provide flexibility in
problematic cases, without degrading quality elsewhere. We also propose
an additional optimization criterion, legibility, which allows us to
simultaneously optimize over label formatting, font size, and
orientation. To solve this revised optimization problem, we describe the
optimization function and an efficient search algorithm. Finally, we
compare our method to previous work using both quantitative and
qualitative metrics. This paper is a good example of how ideas from
automated graphic design can be applied to information visualization. expand
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Stacking Graphic Elements to Avoid Over-Plotting |
|
Tuan Nhon Dang,
Leland Wilkinson,
Anushka Anand
|
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Pages: 1044-1052 |
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doi>10.1109/TVCG.2010.197 |
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Full text available:
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An
ongoing challenge for information visualization is how to deal with
over-plotting forced by ties or the relatively limitedvisual field of
display devices. A popular solution is to represent local data density
with area (bubble plots, treemaps), color(heatmaps), ...
An
ongoing challenge for information visualization is how to deal with
over-plotting forced by ties or the relatively limitedvisual field of
display devices. A popular solution is to represent local data density
with area (bubble plots, treemaps), color(heatmaps), or aggregation
(histograms, kernel densities, pixel displays). All of these methods
have at least one of three deficiencies:1) magnitude judgments are
biased because area and color have convex downward perceptual functions,
2) area, hue, and brightnesshave relatively restricted ranges of
perceptual intensity compared to length representations, and/or 3) it is
difficult to brush or link toindividual cases when viewing
aggregations. In this paper, we introduce a new technique for
visualizing and interacting with datasetsthat preserves density
information by stacking overlapping cases. The overlapping data can be
points or lines or other geometricelements, depending on the type of
plot. We show real-dataset applications of this stacking paradigm and
compare them to othertechniques that deal with over-plotting in
high-dimensional displays. expand
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Visualization of Diversity in Large Multivariate Data Sets |
|
Tuan Pham,
Rob Hess,
Crystal Ju,
Eugene Zhang,
Ronald Metoyer
|
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Pages: 1053-1062 |
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doi>10.1109/TVCG.2010.216 |
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Full text available:
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Understanding
the diversity of a set of multivariate objects is an important problem
in many domains, including ecology, college admissions, investing,
machine learning, and others. However, to date, very little work has
been done to help users achieve ...
Understanding
the diversity of a set of multivariate objects is an important problem
in many domains, including ecology, college admissions, investing,
machine learning, and others. However, to date, very little work has
been done to help users achieve this kind of understanding. Visual
representation is especially appealing for this task because it offers
the potential to allow users to efficiently observe the objects of
interest in a direct and holistic way. Thus, in this paper, we attempt
to formalize the problem of visualizing the diversity of a large (more
than 1000 objects), multivariate (more than 5 attributes) data set as
one worth deeper investigation by the information visualization
community. In doing so, we contribute a precise definition of diversity,
a set of requirements for diversity visualizations based on this
definition, and a formal user study design intended to evaluate the
capacity of a visual representation for communicating diversity
information. Our primary contribution, however, is a visual
representation, called the Diversity Map, for visualizing diversity. An
evaluation of the Diversity Map using our study design shows that users
can judge elements of diversity consistently and as or more accurately
than when using the only other representation specifically designed to
visualize diversity. expand
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PedVis: A Structured, Space-Efficient Technique for Pedigree Visualization |
|
Claurissa Tuttle,
Luis Gustavo Nonato,
Claudio Silva
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Pages: 1063-1072 |
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doi>10.1109/TVCG.2010.185 |
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Public
genealogical databases are becoming increasingly populated with
historical data and records of the current population's ancestors.As
this increasing amount of available information is used to link
individuals to their ancestors, the resulting ...
Public
genealogical databases are becoming increasingly populated with
historical data and records of the current population's ancestors.As
this increasing amount of available information is used to link
individuals to their ancestors, the resulting trees become deeper and
more dense, which justifies the need for using organized,
space-efficient layouts to display the data.Existing layouts are often
only able to show a small subset of the data at a time.As a result, it
is easy to become lost when navigating through the data or to lose sight
of the overall tree structure.On the contrary, leaving space for
unknown ancestors allows one to better understand the tree's structure,
but leaving this space becomes expensive and allows fewer generations to
be displayed at a time.In this work, we propose that the H-tree based
layout be used in genealogical software to display ancestral trees.We
will show that this layout presents an increase in the number of
displayable generations, provides a nicely arranged, symmetrical,
intuitive and organized fractal structure, increases the user's ability
to understand and navigate through the data, and accounts for the
visualization requirements necessary for displaying such trees.Finally,
user-study results indicate potential for user acceptance of the new
layout. expand
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GeneaQuilts: A System for Exploring Large Genealogies |
|
Anastasia Bezerianos,
Pierre Dragicevic,
Jean-Daniel Fekete,
Juhee Bae,
Ben Watson
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Pages: 1073-1081 |
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doi>10.1109/TVCG.2010.159 |
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GeneaQuilts
is a new visualization technique for representing large genealogies of
up to several thousand individuals. Thevisualization takes the form of a
diagonally-filled matrix, where rows are individuals and columns are
nuclear families. After identifyingthe ...
GeneaQuilts
is a new visualization technique for representing large genealogies of
up to several thousand individuals. Thevisualization takes the form of a
diagonally-filled matrix, where rows are individuals and columns are
nuclear families. After identifyingthe major tasks performed in
genealogical research and the limits of current software, we present an
interactive genealogy explorationsystem based on GeneaQuilts. The system
includes an overview, a timeline, search and filtering components, and a
new interactiontechnique called Bring & Slide that allows fluid
navigation in very large genealogies. We report on preliminary feedback
from domain experts and show how our system supports a number of their
tasks. expand
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Visualization of Graph Products |
|
Stefan Janicke,
Christian Heine,
Marc Hellmuth,
Peter F. Stadler,
Gerik Scheuermann
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Pages: 1082-1089 |
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doi>10.1109/TVCG.2010.217 |
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Graphs
are a versatile structure and abstraction for binary relationships
between objects. To gain insight into such relationships, their
corresponding graph can be visualized. In the past, many classes of
graphs have been defined, e.g. trees, planar ...
Graphs
are a versatile structure and abstraction for binary relationships
between objects. To gain insight into such relationships, their
corresponding graph can be visualized. In the past, many classes of
graphs have been defined, e.g. trees, planar graphs, directed acyclic
graphs, and visualization algorithms were proposed for these classes.
Although many graphs may only be classified as "general" graphs, they
can contain substructures that belong to a certain class. Archambault
proposed the TopoLayout framework: rather than draw any arbitrary graph
using one method, split the graph into components that are homogeneous
with respect to one graph class and then draw each component with an
algorithm best suited for this class. Graph products constitute a class
that arises frequently in graph theory, but for which no visualization
algorithm has been proposed until now. In this paper, we present an
algorithm for drawing graph products and the aesthetic criterion graph
product's drawings are subject to. We show that the popular
High-Dimensional Embedder approach applied to cartesian products already
respects this aestetic criterion, but has disadvantages. We also
present how our method is integrated as a new component into the
TopoLayout framework. Our implementation is used for further research of
graph products in a biological context. expand
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Untangling Euler Diagrams |
|
Nathalie Henry Riche,
Tim Dwyer
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Pages: 1090-1099 |
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doi>10.1109/TVCG.2010.210 |
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In
many common data analysis scenarios the data elements are logically
grouped into sets. Venn and Euler style diagrams are a common visual
representation of such set membership where the data elements are
represented by labels or glyphs and sets are ...
In
many common data analysis scenarios the data elements are logically
grouped into sets. Venn and Euler style diagrams are a common visual
representation of such set membership where the data elements are
represented by labels or glyphs and sets are indicated by boundaries
surrounding their members. Generating such diagrams automatically such
that set regions do not intersect unless the corresponding sets have a
non-empty intersection is a difficult problem. Further, it may be
impossible in some cases if regions are required to be continuous and
convex. Several approaches exist to draw such set regions using more
complex shapes, however, the resulting diagrams can be difficult to
interpret. In this paper we present two novel approaches for simplifying
a complex collection of intersecting sets into a strict hierarchy that
can be more easily automatically arranged and drawn (Figure 1). In the
first approach, we use compact rectangular shapes for drawing each set,
attempting to improve the readability of the set intersections. In the
second approach, we avoid drawing intersecting set regions by
duplicating elements belonging to multiple sets. We compared both of our
techniques to the traditional non-convex region technique using five
readability tasks. Our results show that the compact rectangular shapes
technique was often preferred by experimental subjects even though the
use of duplications dramatically improves the accuracy and performance
time for most of our tasks. In addition to general set representation
our techniques are also applicable to visualization of networks with
intersecting clusters of nodes expand
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The FlowVizMenu and Parallel Scatterplot Matrix: Hybrid Multidimensional Visualizations for Network Exploration |
|
Christophe Viau,
Michael J. McGuffin,
Yves Chiricota,
Igor Jurisica
|
|
Pages: 1100-1108 |
|
doi>10.1109/TVCG.2010.205 |
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Full text available:
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A
standard approach for visualizing multivariate networks is to use one
or more multidimensional views (for example, scatterplots) for selecting
nodes by various metrics, possibly coordinated with a node-link view of
the network. In this paper, we present ...
A
standard approach for visualizing multivariate networks is to use one
or more multidimensional views (for example, scatterplots) for selecting
nodes by various metrics, possibly coordinated with a node-link view of
the network. In this paper, we present three novel approaches for
achieving a tighter integration of these views through hybrid techniques
for multidimensional visualization, graph selection and layout. First,
we present the FlowVizMenu, a radial menu containing a scatterplot that
can be popped up transiently and manipulated with rapid, fluid gestures
to select and modify the axes of its scatterplot. Second, the
FlowVizMenu can be used to steer an attribute-driven layout of the
network, causing certain nodes of a node-link diagram to move toward
their corresponding positions in a scatterplot while others can be
positioned manually or by force-directed layout. Third, we describe a
novel hybrid approach that combines a scatterplot matrix (SPLOM) and
parallel coordinates called the Parallel Scatterplot Matrix (P-SPLOM),
which can be used to visualize and select features within the network.
We also describe a novel arrangement of scatterplots called the
Scatterplot Staircase (SPLOS) that requires less space than a
traditional scatterplot matrix. Initial user feedback is reported. expand
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OpinionSeer: Interactive Visualization of Hotel Customer Feedback |
|
Yingcai Wu,
Furu Wei,
Shixia Liu,
Norman Au,
Weiwei Cui,
Hong Zhou,
Huamin Qu
|
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Pages: 1109-1118 |
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doi>10.1109/TVCG.2010.183 |
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Full text available:
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The
rapid development of Web technology has resulted in an increasing
number of hotel customers sharing their opinionson the hotel services.
Effective visual analysis of online customer opinions is needed, as it
has a significant impact on buildinga ...
The
rapid development of Web technology has resulted in an increasing
number of hotel customers sharing their opinionson the hotel services.
Effective visual analysis of online customer opinions is needed, as it
has a significant impact on buildinga successful business. In this
paper, we present OpinionSeer, an interactive visualization system that
could visually analyze alarge collection of online hotel customer
reviews. The system is built on a new visualization-centric opinion
mining technique thatconsiders uncertainty for faithfully modeling and
analyzing customer opinions. A new visual representation is developed to
conveycustomer opinions by augmenting well-established scatterplots and
radial visualization. To provide multiple-level exploration,
weintroduce subjective logic to handle and organize subjective opinions
with degrees of uncertainty. Several case studies illustrate
theeffectiveness and usefulness of OpinionSeer on analyzing
relationships among multiple data dimensions and comparing opinionsof
different groups. Aside from data on hotel customer feedback,
OpinionSeer could also be applied to visually analyze customeropinions
on other products or services. expand
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The Streams of Our Lives: Visualizing Listening Histories in Context |
|
Dominikus Baur,
Frederik Seiffert,
Michael Sedlmair,
Sebastian Boring
|
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Pages: 1119-1128 |
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doi>10.1109/TVCG.2010.206 |
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Full text available:
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The
choices we take when listening to music are expressions of our personal
taste and character. Storing and accessing our listening histories is
trivial due to services like Last.fm, but learning from them and
understanding them is not. Existing solutions ...
The
choices we take when listening to music are expressions of our personal
taste and character. Storing and accessing our listening histories is
trivial due to services like Last.fm, but learning from them and
understanding them is not. Existing solutions operate at a very abstract
level and only produce statistics. By applying techniques from
information visualization to this problem, we were able to provide
average people with a detailed and powerful tool for accessing their own
musical past. LastHistory is an interactive visualization for
displaying music listening histories, along with contextual information
from personal photos and calendar entries. Its two main user tasks are
(1) analysis, with an emphasis on temporal patterns and hypotheses
related to musical genre and sequences, and (2) reminiscing, where
listening histories and context represent part of one's past. In this
design study paper we give an overview of the field of music listening
histories and explain their unique characteristics as a type of personal
data. We then describe the design rationale, data and view
transformations of LastHistory and present the results from both a lab-
and a large-scale online study. We also put listening histories in
contrast to other lifelogging data. The resonant and enthusiastic
feedback that we received from average users shows a need for making
their personal data accessible. We hope to stimulate such developments
through this research. expand
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A Visual Backchannel for Large-Scale Events |
|
Marian Dork,
Daniel Gruen,
Carey Williamson,
Sheelagh Carpendale
|
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Pages: 1129-1138 |
|
doi>10.1109/TVCG.2010.129 |
|
Full text available:
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We
introduce the concept of a Visual Backchannel as a novel way of
following and exploring online conversations aboutlarge-scale events.
Microblogging communities, such as Twitter, are increasingly used as
digital backchannels for timely exchange ofbrief ...
We
introduce the concept of a Visual Backchannel as a novel way of
following and exploring online conversations aboutlarge-scale events.
Microblogging communities, such as Twitter, are increasingly used as
digital backchannels for timely exchange ofbrief comments and
impressions during political speeches, sport competitions, natural
disasters, and other large events. Currently,shared updates are
typically displayed in the form of a simple list, making it difficult to
get an overview of the fast-paced discussions asit happens in the
moment and how it evolves over time. In contrast, our Visual Backchannel
design provides an evolving, interactive,and multi-faceted visual
overview of large-scale ongoing conversations on Twitter. To visualize a
continuously updating informationstream, we include visual saliency for
what is happening now and what has just happened, set in the context of
the evolving conversation.As part of a fully web-based coordinated-view
system we introduce Topic Streams, a temporally adjustable stacked
graphvisualizing topics over time, a People Spiral representing
participants and their activity, and an Image Cloud encoding the
popularityof event photos by size. Together with a post listing, these
mutually linked views support cross-filtering along topics,
participants, andtime ranges. We discuss our design considerations, in
particular with respect to evolving visualizations of dynamically
changing data.Initial feedback indicates significant interest and
suggests several unanticipated uses. expand
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Narrative Visualization: Telling Stories with Data |
|
Edward Segel,
Jeffrey Heer
|
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Pages: 1139-1148 |
|
doi>10.1109/TVCG.2010.179 |
|
Full text available:
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Data
visualization is regularly promoted for its ability to reveal stories
within data, yet these “data stories” differ in important ways from
traditional forms of storytelling. Storytellers, especially online
journalists, have increasingly ...
Data
visualization is regularly promoted for its ability to reveal stories
within data, yet these “data stories” differ in important ways from
traditional forms of storytelling. Storytellers, especially online
journalists, have increasingly been integrating visualizations intotheir
narratives, in some cases allowing the visualization to function in
place of a written story. In this paper, we systematically review the
design space of this emerging class of visualizations. Drawing on case
studies from news media to visualization research, we identify distinct
genres of narrative visualization. We characterize these design
differences, together with interactivity and messaging, in terms of the
balance between the narrative flow intended by the author (imposed by
graphical elements and the interface) and story discovery on the part of
the reader (often through interactive exploration). Our framework
suggests design strategies for narrative visualization, including
promising under-explored approaches to journalistic storytelling and
educational media. expand
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Declarative Language Design for Interactive Visualization |
|
Jeffrey Heer,
Michael Bostock
|
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Pages: 1149-1156 |
|
doi>10.1109/TVCG.2010.144 |
|
Full text available:
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We
investigate the design of declarative, domain-specific languages for
constructing interactive visualizations. By separatingspecification from
execution, declarative languages can simplify development, enable
unobtrusive optimization, and supportretargeting ...
We
investigate the design of declarative, domain-specific languages for
constructing interactive visualizations. By separatingspecification from
execution, declarative languages can simplify development, enable
unobtrusive optimization, and supportretargeting across platforms. We
describe the design of the Protovis specification language and its
implementation within anobject-oriented, statically-typed programming
language (Java). We demonstrate how to support rich visualizations
without requiring atoolkit-specific data model and extend Protovis to
enable declarative specification of animated transitions. To support
cross-platformdeployment, we introduce rendering and event-handling
infrastructures decoupled from the runtime platform, letting designers
retargetvisualization specifications (e.g., from desktop to mobile
phone) with reduced effort. We also explore optimizations such as
runtimecompilation of visualization specifications, parallelized
execution, and hardware-accelerated rendering. We present benchmark
studiesmeasuring the performance gains provided by these optimizations
and compare performance to existing Java-based visualizationtools,
demonstrating scalability improvements exceeding an order of magnitude. expand
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WebCharts: Extending Applications with Web-Authored, Embeddable Visualizations |
|
Danyel Fisher,
Steven Drucker,
Roland Fernandez,
Scott Ruble
|
|
Pages: 1157-1163 |
|
doi>10.1109/TVCG.2010.222 |
|
Full text available:
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In
order to use new visualizations, most toolkits require application
developers to rebuild their applications and distribute new versions to
users. The WebCharts Framework take a different approach by hosting
JavaScript from within an application and ...
In
order to use new visualizations, most toolkits require application
developers to rebuild their applications and distribute new versions to
users. The WebCharts Framework take a different approach by hosting
JavaScript from within an application and providing a standard data and
events interchange. In this way, applications can be extended
dynamically, with a wide variety of visualizations. We discuss the
benefits of this architectural approach, contrast it to existing
techniques, and give a variety of examples and extensions of the basic
system. expand
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“behaviorism”: a framework for dynamic data visualization |
|
Angus Forbes,
Tobias Hollerer,
George Legrady
|
|
Pages: 1164-1171 |
|
doi>10.1109/TVCG.2010.126 |
|
Full text available:
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While
a number of information visualization software frameworks exist,
creating new visualizations, especially those that involve novel
visualization metaphors, interaction techniques, data analysis
strategies, and specialized rendering algorithms, is ...
While
a number of information visualization software frameworks exist,
creating new visualizations, especially those that involve novel
visualization metaphors, interaction techniques, data analysis
strategies, and specialized rendering algorithms, is still often a
difficult process. To facilitate the creation of novel visualizations we
present a new software framework, behaviorism, which provides a wide
range of flexibility when working with dynamic information on visual,
temporal, and ontological levels, but at the same time providing
appropriate abstractions which allow developers to create prototypes
quickly which can then easily be turned into robust systems. The core of
the framework is a set of three interconnected graphs, each with
associated operators: a scene graph for high-performance 3D rendering, a
data graph for different layers of semantically linked heterogeneous
data, and a timing graph for sophisticated control of scheduling,
interaction, and animation. In particular, the timing graph provides a
unified system to add behaviors to both data and visual elements, as
well as to the behaviors themselves. To evaluate the framework we look
briefly at three different projects all of which required novel
visualizations in different domains, and all of which worked with
dynamic data in different ways: an interactive ecological simulation, an
information art installation, and an information visualization
technique. expand
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FacetAtlas: Multifaceted Visualization for Rich Text Corpora |
|
Nan Cao,
Jimeng Sun,
Yu-Ru Lin,
David Gotz,
Shixia Liu,
Huamin Qu
|
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Pages: 1172-1181 |
|
doi>10.1109/TVCG.2010.154 |
|
Full text available:
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Documents
in rich text corpora usually contain multiple facets of information.
For example, an article about a specific disease often consists of
different facets such as symptom, treatment, cause, diagnosis,
prognosis, and prevention. Thus, documents ...
Documents
in rich text corpora usually contain multiple facets of information.
For example, an article about a specific disease often consists of
different facets such as symptom, treatment, cause, diagnosis,
prognosis, and prevention. Thus, documents may have different relations
based on different facets. Powerful search tools have been developed to
help users locate lists of individual documents that are most related to
specific keywords. However, there is a lack of effective analysis tools
that reveal the multifaceted relations of documents within or cross the
document clusters. In this paper, we present FacetAtlas, a multifaceted
visualization technique for visually analyzing rich text corpora.
FacetAtlas combines search technology with advanced visual analytical
tools to convey both global and local patterns simultaneously. We
describe several unique aspects of FacetAtlas, including (1) node
cliques and multifaceted edges, (2) an optimized density map, and (3)
automated opacity pattern enhancement for highlighting visual patterns,
(4) interactive context switch between facets. In addition, we
demonstrate the power of FacetAtlas through a case study that targets
patient education in the health care domain. Our evaluation shows the
benefits of this work, especially in support of complex multifaceted
data analysis. expand
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SparkClouds: Visualizing Trends in Tag Clouds |
|
Bongshin Lee,
Nathalie Henry Riche,
Amy K. Karlson,
Sheelash Carpendale
|
|
Pages: 1182-1189 |
|
doi>10.1109/TVCG.2010.194 |
|
Full text available:
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Tag
clouds have proliferated over the web over the last decade. They
provide a visual summary of a collection of texts by visually depicting
the tag frequency by font size. In use, tag clouds can evolve as the
associated data source changes over time. ...
Tag
clouds have proliferated over the web over the last decade. They
provide a visual summary of a collection of texts by visually depicting
the tag frequency by font size. In use, tag clouds can evolve as the
associated data source changes over time. Interesting discussions around
tag clouds often include a series of tag clouds and consider how they
evolve over time. However, since tag clouds do not explicitly represent
trends or support comparisons, the cognitive demands placed on the
person for perceiving trends in multiple tag clouds are high. In this
paper, we introduce SparkClouds, which integrate sparklines [23] into a
tag cloud to convey trends between multiple tag clouds. We present
results from a controlled study that compares SparkClouds with two
traditional trend visualizations—multiple line graphs and stacked bar
charts—as well as Parallel TagClouds [4]. Results show that SparkClouds
ability to show trends compares favourably to thealternative
visualizations. expand
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ManiWordle: Providing Flexible Control over Wordle |
|
Kyle Koh,
Bongshin Lee,
Bohyoung Kim,
Jinwook Seo
|
|
Pages: 1190-1197 |
|
doi>10.1109/TVCG.2010.175 |
|
Full text available:
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Among
the multifarious tag-clouding techniques, Wordle stands out to the
community by providing an aesthetic layout, eliciting the emergence of
the participatory culture and usage of tag-clouding in the artistic
creations. In this paper, we introduce ...
Among
the multifarious tag-clouding techniques, Wordle stands out to the
community by providing an aesthetic layout, eliciting the emergence of
the participatory culture and usage of tag-clouding in the artistic
creations. In this paper, we introduce ManiWordle, a Wordle-based
visualization tool that revamps interactions with the layout by
supporting custom manipulations. ManiWordle allows people to manipulate
typography, color, and composition not only for the layout as a whole,
but also for the individual words, enabling them to have better control
over the layout result. We first describe our design rationale along
with the interaction techniques for tweaking the layout. We then present
the results both from the preliminary usability study and from the
comparative study between ManiWordle and Wordle. The results suggest
that ManiWordle provides higher user satisfaction and an efficient
method of creating the desired "art work," harnessing the power behind
the ever-increasing popularity of Wordle. expand
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On the Fractal Dimension of Isosurfaces |
|
Marc Khoury,
Rephael Wenger
|
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Pages: 1198-1205 |
|
doi>10.1109/TVCG.2010.182 |
|
Full text available:
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A
(3D) scalar grid is a regular $n_1 x n_2 x n_3$ grid of vertices where
each vertex v is associated with some scalar value $s_v$. ;Applying
trilinear interpolation, the scalar grid determines a scalar function g
where $g(v) = s_v$ for each grid vertex ...
A
(3D) scalar grid is a regular $n_1 x n_2 x n_3$ grid of vertices where
each vertex v is associated with some scalar value $s_v$. ;Applying
trilinear interpolation, the scalar grid determines a scalar function g
where $g(v) = s_v$ for each grid vertex v. An isosurface with ;isovalue s
is a triangular mesh which approximates the level set $g^{-1}(α)$. The
fractal dimension of an isosurface represents the growth ;in the
isosurface as the number of grid cubes increases. We dene and discuss
the fractal isosurface dimension. Plotting the fractal ;dimension as a
function of the isovalues in a data set provides information about the
isosurfaces determined by the data set. We present statistics on the
average fractal dimension of 60 publicly available benchmark data sets.
We also show the fractal dimension is highly correlated with topological
noise in the benchmark data sets, measuring the topological noise by
the number of connected components in the isosurface. Lastly, we present
a formula predicting the fractal dimension as a function of noise and
validate the formula with experimental results. expand
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An Information-theoretic Framework for Visualization |
|
Min Chen,
Heike Jaenicke
|
|
Pages: 1206-1215 |
|
doi>10.1109/TVCG.2010.132 |
|
Full text available:
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In
this paper, we examine whether or not information theory can be one of
the theoretic frameworks for visualization. We formulate concepts and
measurements for qualifying visual information. We illustrate these
concepts with examples that manifest the ...
In
this paper, we examine whether or not information theory can be one of
the theoretic frameworks for visualization. We formulate concepts and
measurements for qualifying visual information. We illustrate these
concepts with examples that manifest the intrinsic and implicit use of
information theory in many existing visualization techniques. We outline
the broad correlation between visualization and the major applications
of information theory, while pointing out the difference in emphasis and
some technical gaps. Our study provides compelling evidence that
information theory can explain a significant number of phenomena or
events in visualization, while no example has been found which is
fundamentally in conflict with information theory. We also notice that
the emphasis of some traditional applications of information theory,
such as data compression or data communication, may not always suit
visualization, as the former typically focuses on the efficient
throughput of a communication channel, whilst the latter focuses on the
effectiveness in aiding the perceptual and cognitive process for data
understanding and knowledge discovery. These findings suggest that
further theoretic developments are necessary for adopting and adapting
information theory for visualization. expand
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An Information-Theoretic Framework for Flow Visualization |
|
Lijie Xu,
Teng-Yok Lee,
Han-Wei Shen
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Pages: 1216-1224 |
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doi>10.1109/TVCG.2010.131 |
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Full text available:
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The
process of visualization can be seen as a visual communication channel
where the input to the channel is the raw data, and the output is the
result of a visualization algorithm. From this point of view, we can
evaluate the effectiveness of visualization ...
The
process of visualization can be seen as a visual communication channel
where the input to the channel is the raw data, and the output is the
result of a visualization algorithm. From this point of view, we can
evaluate the effectiveness of visualization by measuring how much
information in the original data is being communicated through the
visual communication channel. In this paper, we present an
information-theoretic framework for flow visualization with a special
focus on streamline generation. In our framework, a vector field is
modeled as a distribution of directions from which Shannon's entropy is
used to measure the information content in the field. The effectiveness
of the streamlines displayed in visualization can be measured by first
constructing a new distribution of vectors derived from the existing
streamlines, and then comparing this distribution with that of the
original data set using the conditional entropy. The conditional entropy
between these two distributions indicates how much information in the
original data remains hidden after the selected streamlines are
displayed. The quality of the visualization can be improved by
progressively introducing new streamlines until the conditional entropy
converges to a small value. We describe the key components of our
framework with detailed analysis, and show that the framework can
effectively visualize 2D and 3D flow data. expand
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Streak Lines as Tangent Curves of a Derived Vector Field |
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Tino Weinkauf,
Holger Theisel
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Pages: 1225-1234 |
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doi>10.1109/TVCG.2010.198 |
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Characteristic
curves of vector fields include stream, path, and streak lines. Stream
and path lines can be obtained by a simple vector field integration of
an autonomous ODE system, i.e., they can be described as tangent curves
of a vector field. This ...
Characteristic
curves of vector fields include stream, path, and streak lines. Stream
and path lines can be obtained by a simple vector field integration of
an autonomous ODE system, i.e., they can be described as tangent curves
of a vector field. This facilitates their mathematical analysis
including the extraction of core lines around which stream or path lines
exhibit swirling motion, or the computation of their curvature for
every point in the domain without actually integrating them. Such a
description of streak lines is not yet available, which excludes them
from most of the feature extraction and analysis tools that have been
developed in our community. In this paper, we develop the first
description of streak lines as tangent curves of a derived vector field -
the streak line vector field - and show how it can be computed from the
spatial and temporal gradients of the flow map, i.e., a dense path line
integration is required. We demonstrate the high accuracy of our
approach by comparing it to solutions where the ground truth is
analytically known and to solutions where the ground truth has been
obtained using the classic streak line computation. Furthermore, we
apply a number of feature extraction and analysis tools to the new
streak line vector field including the extraction of cores of swirling
streak lines and the computation of streak line curvature fields. These
first applications foreshadow the large variety of possible future
research directions based on our new mathematical description of streak
lines. expand
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A Curved Ray Camera for Handling Occlusions through Continuous Multiperspective Visualization |
|
Jian Cui,
Paul Rosen,
Voicu Popescu,
Christoph Hoffmann
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Pages: 1235-1242 |
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doi>10.1109/TVCG.2010.127 |
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Most
images used in visualization are computed with the planar pinhole
camera. This classic camera model has important advantages such as
simplicity, which enables efficient software and hardware
implementations, and similarity to the human eye, which ...
Most
images used in visualization are computed with the planar pinhole
camera. This classic camera model has important advantages such as
simplicity, which enables efficient software and hardware
implementations, and similarity to the human eye, which yields images
familiar to the user. However, the planar pinhole camera has only a
single viewpoint, which limits images to parts of the scene to which
there is direct line of sight. In this paper we introduce the curved ray
camera to address the single viewpoint limitation. Rays are
C1-continuous curves that bend to circumvent occluders. Our camera is
designed to provide a fast 3-D point projection operation, which enables
interactive visualization. The camera supports both 3-D surface and
volume datasets. The camera is a powerful tool that enables seamless
integration of multiple perspectives for overcoming occlusions in
visualization while minimizing distortions. expand
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Special Relativistic Visualization by Local Ray Tracing |
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Thomas Muller,
Sebastian Grottel,
Daniel Weiskopf
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Pages: 1243-1250 |
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doi>10.1109/TVCG.2010.196 |
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Special
relativistic visualization offers the possibility of experiencing the
optical effects of traveling near the speed of light, including apparent
geometric distortions as well as Doppler and searchlight effects. Early
high-quality computer graphics ...
Special
relativistic visualization offers the possibility of experiencing the
optical effects of traveling near the speed of light, including apparent
geometric distortions as well as Doppler and searchlight effects. Early
high-quality computer graphics images of relativistic scenes were
created using offline, computationally expensive CPU-side 4D ray
tracing. Alternate approaches such as image-based rendering and
polygon-distortion methods are able to achieve interactivity, but
exhibit inferior visual quality due to sampling artifacts. In this
paper, we introduce a hybrid rendering technique based on polygon
distortion and local ray tracing that facilitates interactive
high-quality visualization of multiple objects moving at relativistic
speeds in arbitrary directions. The method starts by calculating tight
image-space footprints for the apparent triangles of the 3D scene
objects. The final image is generated using a single image-space ray
tracing step incorporating Doppler and searchlight effects. Our
implementation uses GPU shader programming and hardware texture
filtering to achieve high rendering speed. expand
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Computing Robustness and Persistence for Images |
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Paul Bendich,
Herbert Edelsbrunner,
Michael Kerber
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Pages: 1251-1260 |
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doi>10.1109/TVCG.2010.139 |
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We
are interested in 3-dimensional images given as arrays of voxels with
intensity values. Extending these values to acontinuous function, we
study the robustness of homology classes in its level and interlevel
sets, that is, the amount of perturbationneeded ...
We
are interested in 3-dimensional images given as arrays of voxels with
intensity values. Extending these values to acontinuous function, we
study the robustness of homology classes in its level and interlevel
sets, that is, the amount of perturbationneeded to destroy these
classes. The structure of the homology classes and their robustness,
over all level and interlevel sets, can bevisualized by a triangular
diagram of dots obtained by computing the extended persistence of the
function. We give a fast hierarchicalalgorithm using the dual complexes
of oct-tree approximations of the function. In addition, we show that
for balanced oct-trees, thedual complexes are geometrically realized in
$R^3$ and can thus be used to construct level and interlevel sets. We
apply these tools tostudy 3-dimensional images of plant root systems. expand
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Browsing Large Image Datasets through Voronoi Diagrams |
|
Paolo Brivio,
Marco Tarini,
Paolo Cignoni
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Pages: 1261-1270 |
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doi>10.1109/TVCG.2010.136 |
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Full text available:
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Conventional
browsing of image collections use mechanisms such as thumbnails
arranged on a regular grid or on a line,often mounted over a scrollable
panel. However, this approach does not scale well with the size of the
datasets (number of images).In ...
Conventional
browsing of image collections use mechanisms such as thumbnails
arranged on a regular grid or on a line,often mounted over a scrollable
panel. However, this approach does not scale well with the size of the
datasets (number of images).In this paper, we propose a new
thumbnail-based interface to browse large collections of images. Our
approach is based on weightedcentroidal anisotropic Voronoi diagrams. A
dynamically changing subset of images is represented by thumbnails and
shown on the screen. Thumbnails are shaped like general polygons, to
better cover screen space, while still reflecting the original aspect
ratios or orientation of the represented images. During the browsing
process, thumbnails are dynamically rearranged, reshaped and rescaled.
The objective is to devote more screen space (more numerous and larger
thumbnails) to the parts of the dataset closer to the current region of
interest, and progressively lesser away from it, while still making the
dataset visible as a whole. During the entire process, temporal
coherence is always maintained. GPU implementation easily guarantees the
frame rates needed for fully smooth interactivity. expand
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Visual Exploration of High Dimensional Scalar Functions |
|
Samuel Gerber,
Peer-Timo Bremer,
Valerio Pascucci,
Ross Whitaker
|
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Pages: 1271-1280 |
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doi>10.1109/TVCG.2010.213 |
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Full text available:
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An
important goal of scientific data analysis is to understand thebehavior
of a system or process based on a sample of the system.In manyinstances
it is possible to observe both input parameters and system outputs, and
characterize the system as a high-dimensional ...
An
important goal of scientific data analysis is to understand thebehavior
of a system or process based on a sample of the system.In manyinstances
it is possible to observe both input parameters and system outputs, and
characterize the system as a high-dimensional function. Such data
setsarise, for instance, in large numerical simulations, as energy
landscapes inoptimization problems, or in the analysis of image data
relating to biological ormedical parameters.This paper proposes an
approach to analyze and visualizing such datasets.The proposed method
combines topological and geometric techniques toprovide interactive
visualizations of discretely sampled high-dimensionalscalar fields.The
method relies on a segmentation of the parameter space usingan
approximate Morse-Smale complex on the cloud of point samples. For
eachcrystal of the Morse-Smale complex, a regression of the system
parameters withrespect to the output yields a curve in the parameter
space. The result is asimplified geometric representation of the
Morse-Smale complex in the highdimensional input domain.Finally, the
geometric representation is embeddedin 2D, using dimension reduction, to
provide a visualization platform. Thegeometric properties of the
regression curves enable the visualization ofadditional information
about each crystal such as local and global shape, width,length, and
sampling densities. The method is illustrated on several synthetic
examples of two dimensionalfunctions. Two use cases, using data sets
from the UCI machine learning repository, demonstrate the utility of the
proposed approach on real data.Finally, in collaboration with domain
experts the proposed method is applied totwo scientific challenges. The
analysis of parameters of climate simulationsand their relationship to
predicted global energy flux and the concentrationsof chemical species
in a combustion simulation and their integration withtemperature. expand
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Two-Phase Mapping for Projecting Massive Data Sets |
|
Fernando V. Paulovich,
Claudio T. Silva,
Luis G. Nonato
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Pages: 1281-1290 |
|
doi>10.1109/TVCG.2010.207 |
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Full text available:
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Most
multidimensional projection techniques rely on distance (dissimilarity)
information between data instances to embed high-dimensional data into a
visual space. When data are endowed with Cartesian coordinates, an
extra computational effort is necessary ...
Most
multidimensional projection techniques rely on distance (dissimilarity)
information between data instances to embed high-dimensional data into a
visual space. When data are endowed with Cartesian coordinates, an
extra computational effort is necessary to compute the needed distances,
making multidimensional projection prohibitive in applications dealing
with interactivity and massive data. The novel multidimensional
projection technique proposed in this work, called Part-Linear
Multidimensional Projection (PLMP), has been tailored to handle
multivariate data represented in Cartesian high-dimensional spaces,
requiring only distance information between pairs of representative
samples. This characteristic renders PLMP faster than previous methods
when processing large data sets while still being competitive in terms
of precision. Moreover, knowing the range of variation for data
instances in the high-dimensional space, we can make PLMP a truly
streaming data projection technique, a trait absent in previous methods. expand
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Discontinuities in Continuous Scatter Plots |
|
Dirk J. Lehmann,
Holger Theisel
|
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Pages: 1291-1300 |
|
doi>10.1109/TVCG.2010.146 |
|
Full text available:
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The
concept of continuous scatterplot (CSP) is a modern visualization
technique.The idea is to define a scalar density value based on the map
between an n-dimensional spatial domain and an m-dimensional data
domain, which describe the CSP space. Usually ...
The
concept of continuous scatterplot (CSP) is a modern visualization
technique.The idea is to define a scalar density value based on the map
between an n-dimensional spatial domain and an m-dimensional data
domain, which describe the CSP space. Usually the data domain is
two-dimensional to visually convey the underlying, density coded, data.
In this paper we investigate kinds of map-based discontinuities,
especially for the practical cases n = m = 2 and n = 3 | m = 2, and we
depict relations between them and attributes of the resulting CSP
itself.Additionally, we show that discontinuities build critical line
structures, and we introduce algorithms to detect them. Further, we
introduce a discontinuity-based visualization approach—called
contribution map (CM)—which establishes a relationship between the CSP's
data domain and the number of connected components in the spatial
domain. We show that CMs enhance the CSP-based linking & brushing
interaction. Finally, we apply our approaches to a number of synthetic
as well as real data sets. expand
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Spatial Conditioning of Transfer Functions Using Local Material Distributions |
|
Stefan Lindholm,
Patric Ljung,
Claes Lundstrom,
Anders Persson,
Anders Ynnerman
|
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Pages: 1301-1310 |
|
doi>10.1109/TVCG.2010.195 |
|
Full text available:
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In
many applications of Direct Volume Rendering (DVR) the importance of a
certain material or feature is highly dependent on its relative spatial
location. For instance, in the medical diagnostic procedure, the
patient's symptoms often lead to specification ...
In
many applications of Direct Volume Rendering (DVR) the importance of a
certain material or feature is highly dependent on its relative spatial
location. For instance, in the medical diagnostic procedure, the
patient's symptoms often lead to specification of features, tissues and
organs of particular interest. One such example is pockets of gas which,
if found inside the body at abnormal locations, are a crucial part of a
diagnostic visualization. This paper presents an approach that enhances
DVR transfer function design with spatial localization based on user
specified material dependencies. Semantic expressions are used to define
conditions based on relations between different materials, such as only
render iodine uptake when close to liver. The underlying methods rely
on estimations of material distributions which are acquired by weighing
local neighborhoods of the data against approximations of material
likelihood functions. This information is encoded and used to influence
rendering according to the user's specifications. The result is improved
focus on important features by allowing the user tosuppress spatially
less-important data. In line with requirements from actual clinical DVR
practice, the methods do not require explicit material segmentation that
would be impossible or prohibitively time-consuming to achieve in most
real cases. The scheme scales well to higher dimensions which accounts
for multi-dimensional transfer functions and multivariate data.
Dual-Energy Computed Tomography, an important new modality in radiology,
is used to demonstrate this scalability. In several examples we show
significantly improved focus on clinically important aspects in the
rendered images. expand
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Exploded View Diagrams of Mathematical Surfaces |
|
Olga Karpenko,
Wilmot Li,
Niloy Mitra,
Maneesh Agrawala
|
|
Pages: 1311-1318 |
|
doi>10.1109/TVCG.2010.151 |
|
Full text available:
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We
present a technique for visualizing complicated mathematical surfaces
that is inspired by hand-designed topologicalillustrations.Our approach
generates exploded views that exposethe internal structure of such a
surface by partitioning it intoparallel ...
We
present a technique for visualizing complicated mathematical surfaces
that is inspired by hand-designed topologicalillustrations.Our approach
generates exploded views that exposethe internal structure of such a
surface by partitioning it intoparallel slices, which are separated from
each other along a singlelinear explosion axis.Our contributions
include a set of simple,prescriptive design rules for choosing an
explosion axis and placingcutting planes, as well as automatic
algorithms for applying theserules.First we analyze the input shape to
select the explosionaxis based on the detected rotational and reflective
symmetries ofthe input model.We then partition the shape into slices
that aredesigned to help viewers better understand how the shape of
thesurface and its cross-sections vary along the explosion axis.Our
algorithms work directly ontriangle meshes, and do not dependon any
specific parameterization of the surface.We generateexploded views for a
variety of mathematical surfaces using oursystem. expand
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IRIS: Illustrative Rendering for Integral Surfaces |
|
Mathias Hummel,
Christoph Garth,
Bernd Hamann,
Hans Hagen,
Kenneth I. Joy
|
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Pages: 1319-1328 |
|
doi>10.1109/TVCG.2010.173 |
|
Full text available:
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Integral
surfaces are ideal tools to illustrate vector fields and fluid flow
structures. However, these surfaces can be visually complex and exhibit
difficult geometric properties, owing to strong stretching, shearing and
folding of the flow from which ...
Integral
surfaces are ideal tools to illustrate vector fields and fluid flow
structures. However, these surfaces can be visually complex and exhibit
difficult geometric properties, owing to strong stretching, shearing and
folding of the flow from which they are derived. Many techniques for
non-photorealistic rendering have been presented previously. It is,
however, unclear how these techniques can be applied to integral
surfaces. In this paper, we examine how transparency and texturing
techniques can be used with integral surfaces to convey both shape and
directional information. We present a rendering pipeline that combines
these techniques aimed at faithfully and accurately representing
integral surfaces while improving visualization insight. The presented
pipeline is implemented directly on the GPU, providing real-time
interaction for all rendering modes, and does not require expensive
preprocessing of integral surfaces after computation. expand
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Illustrative Stream Surfaces |
|
Silvia Born,
Alexander Wiebel,
Jan Friedrich,
Gerik Scheuermann,
Dirk Bartz
|
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Pages: 1329-1338 |
|
doi>10.1109/TVCG.2010.166 |
|
Full text available:
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Stream
surfaces are an intuitive approach to represent 3D vector fields. In
many cases, however, they are challenging objects to visualize and to
understand, due to a high degree of self-occlusion. Despite the need for
adequate rendering methods, little ...
Stream
surfaces are an intuitive approach to represent 3D vector fields. In
many cases, however, they are challenging objects to visualize and to
understand, due to a high degree of self-occlusion. Despite the need for
adequate rendering methods, little work has been done so far in this
important research area. In this paper, we present an illustrative
rendering strategy for stream surfaces. In our approach, we apply
various rendering techniques, which are inspired by the traditional flow
illustrations drawn by Dallmann and Abraham \& Shaw in the early
1980s. Among these techniques are contour lines and halftoning to show
the overall surface shape. Flow direction as well as singularities on
the stream surface are depicted by illustrative surface streamlines. ;To
go beyond reproducing static text book images, we provide several
interaction features, such as movable cuts and slabs allowing an
interactive exploration of the flow and insights into subjacent
structures, e.g., the inner windings of vortex breakdown bubbles. These
methods take only the parameterized stream surface as input, require no
further preprocessing, and can be freely combined by the user. We
explain the design, GPU-implementation, and combination of the different
illustrative rendering and interaction methods and demonstrate the
potential of our approach by applying it to stream surfaces from various
flow simulations. ; expand
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Exploration of 4D MRI Blood Flow using Stylistic Visualization |
|
Roy van Pelt,
Javier Olivan Bescos,
Marcel Breeuwer,
Rachel E. Clough,
M. Eduard Groller,
Bart ter Haar Romenij,
Anna Vilanova
|
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Pages: 1339-1347 |
|
doi>10.1109/TVCG.2010.153 |
|
Full text available:
Publisher Site
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Insight
into the dynamics of blood-flow considerably improves the understanding
of the complex cardiovascular system and its pathologies. Advances in
MRI technology enable acquisition of 4D blood-flow data, providing
quantitative blood-flow velocities ...
Insight
into the dynamics of blood-flow considerably improves the understanding
of the complex cardiovascular system and its pathologies. Advances in
MRI technology enable acquisition of 4D blood-flow data, providing
quantitative blood-flow velocities over time. The currently typical
slice-by-slice analysis requires a full mental reconstruction of the
unsteady blood-flow field, which is a tedious and highly challenging
task, even for skilled physicians. We endeavor to alleviate this task by
means of comprehensive visualization and interaction techniques. In
this paper we present a framework for pre-clinical cardiovascular
research, providing tools to both interactively explore the 4D
blood-flow data and depict the essential blood-flow characteristics. The
framework encompasses a variety of visualization styles, comprising
illustrative techniques as well as improved methods from the established
field of flow visualization. Each of the incorporated styles, including
exploded planar reformats, flow-direction highlights, and arrow-trails,
locally captures the blood-flow dynamics and may be initiated by an
interactively probed vessel cross-section. Additionally, we present the
results of an evaluation with domain experts, measuring the value of
each of the visualization styles and related rendering parameters. expand
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Supine and Prone Colon Registration Using Quasi-Conformal Mapping |
|
Wei Zeng,
Joseph Marino,
Krishna Chaitanya Gurijala,
Xianfeng Gu,
Arie Kaufman
|
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Pages: 1348-1357 |
|
doi>10.1109/TVCG.2010.200 |
|
Full text available:
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In
virtual colonoscopy, CT scans are typically acquired with the patient
in both supine (facing up) and prone (facing down) positions. The
registration of these two scans is desirable so that the user can
clarify situations or confirm polyp findings ...
In
virtual colonoscopy, CT scans are typically acquired with the patient
in both supine (facing up) and prone (facing down) positions. The
registration of these two scans is desirable so that the user can
clarify situations or confirm polyp findings at a location in one scan
with the same location in the other, thereby improving polyp detection
rates and reducing false positives. However, this supine-prone
registration is challenging because of the substantial distortions in
the colon shape due to the patient's change in position. We present an
efficient algorithm and framework for performing this registration
through the use of conformal geometry to guarantee that the registration
is a diffeomorphism (a one-to-one and onto mapping). The taeniae coli
and colon flexures are automatically extracted for each supine and prone
surface, employing the colon geometry. The two colon surfaces are then
divided into several segments using the flexures, and each segment is
cut along a taenia coli and conformally flattened to the rectangular
domain using holomorphic differentials. The mean curvature is color
encoded as texture images, from which feature points are automatically
detected using graph cut segmentation, mathematic morphological
operations, and principal component analysis. Corresponding feature
points are found between supine and prone and are used to adjust the
conformal flattening to be quasi-conformal, such that the features
become aligned. We present multiple methods of visualizing our results,
including 2D flattened rendering, corresponding 3D endoluminal views,
and rendering of distortion measurements.We demonstrate the efficiency
and efficacy of our registration method by illustrating matched views on
both the 2D flattened colon images and in the 3D volume rendered colon
endoluminal view. We analytically evaluate the correctness of the
results by measuring the distance between features on the registered
colons. expand
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Uncertainty-Aware Guided Volume Segmentation |
|
Jorg-Stefan Prassni,
Timo Ropinski,
Klaus Hinrichs
|
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Pages: 1358-1365 |
|
doi>10.1109/TVCG.2010.208 |
|
Full text available:
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Although
direct volume rendering is established as a powerful tool for the
visualization of volumetric data, efficient and reliable feature
detection is still an open topic. Usually, a tradeoff between fast but
imprecise classification schemes and accurate ...
Although
direct volume rendering is established as a powerful tool for the
visualization of volumetric data, efficient and reliable feature
detection is still an open topic. Usually, a tradeoff between fast but
imprecise classification schemes and accurate but time-consuming
segmentation techniques has to be made. Furthermore, the issue of
uncertainty introduced with the feature detection process is completely
neglected by the majority of existing approaches.In this paper we
propose a guided probabilistic volume segmentation approach that focuses
on the minimization of uncertainty. In an iterative process, our system
continuously assesses uncertainty of a random walker-based segmentation
in order to detect regions with high ambiguity, to which the user's
attention is directed to support the correction of potential
misclassifications. This reduces the risk of critical segmentation
errors and ensures that information about the segmentation's reliability
is conveyed to the user in a dependable way. In order to improve the
efficiency of the segmentation process, our technique does not only take
into account the volume data to be segmented, but also enables the user
to incorporate classification information. An interactive workflow has
been achieved by implementing the presented system on the GPU using the
OpenCL API. Our results obtained for several medical data sets of
different modalities, including brain MRI and abdominal CT, demonstrate
the reliability and efficiency of our approach. expand
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Exploration and Visualization of Segmentation Uncertainty using Shape and Appearance Prior Information |
|
Ahmed Saad,
Ghassan Hamarneh,
Torsten Moller
|
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Pages: 1366-1375 |
|
doi>10.1109/TVCG.2010.152 |
|
Full text available:
Publisher Site
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We
develop an interactive analysis and visualization tool for
probabilistic segmentation in medical imaging. The originality of our
approach is that the data exploration is guided by shape and appearance
knowledge learned from expert-segmented images ...
We
develop an interactive analysis and visualization tool for
probabilistic segmentation in medical imaging. The originality of our
approach is that the data exploration is guided by shape and appearance
knowledge learned from expert-segmented images of a training population.
We introduce a set of multidimensional transfer function widgets to
analyze the multivariate probabilistic field data. These widgets furnish
the user with contextual information about conformance or deviation
from the population statistics. We demonstrate the user's ability to
identify suspicious regions (e.g. tumors) and to correct the
misclassification results. We evaluate our system and demonstrate its
usefulness in the context of static anatomical and time-varying
functional imaging datasets. expand
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Edge Aware Anisotropic Diffusion for 3D Scalar Data |
|
Zahid Hosssain,
Torsten Moller
|
|
Pages: 1376-1385 |
|
doi>10.1109/TVCG.2010.147 |
|
Full text available:
Publisher Site
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In
this paper we present a novel anisotropic diffusion model targeted for
3D scalar field data. Our model preserves material boundaries as well as
fine tubular structures while noise is smoothed out. One of the major
novelties is the use of the directional ...
In
this paper we present a novel anisotropic diffusion model targeted for
3D scalar field data. Our model preserves material boundaries as well as
fine tubular structures while noise is smoothed out. One of the major
novelties is the use of the directional second derivative to define
material boundaries instead of the gradient magnitude for thresholding.
This results in a diffusion model that has much lower sensitivity to the
diffusion parameter and smoothes material boundaries consistently
compared to gradient magnitude based techniques. We empirically analyze
the stability and convergence of theproposed diffusion and demonstrate
its de-noising capabilities for both analyticand real data. We also
discuss applications in the context of volume rendering. expand
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Interactive Histology of Large-Scale Biomedical Image Stacks |
|
Won-Ki Jeong,
Jens Schneider,
Stephen Turney,
Beverly E Faulkner-Jones,
Dominik Meyer,
Rudiger Westermann,
R. Clay Reid,
Jeff Lichtman,
Hanspeter Pfister
|
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Pages: 1386-1395 |
|
doi>10.1109/TVCG.2010.168 |
|
Full text available:
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Histology
is the study of the structure of biological tissue using microscopy
techniques. As digital imaging technology advances, high resolution
microscopy of large tissue volumes is becoming feasible; however, new
interactive tools are needed to explore ...
Histology
is the study of the structure of biological tissue using microscopy
techniques. As digital imaging technology advances, high resolution
microscopy of large tissue volumes is becoming feasible; however, new
interactive tools are needed to explore and analyze the enormous
datasets. In this paper we present a visualization framework that
specifically targets interactive examination of arbitrarily large image
stacks. Our framework is built upon two core techniques: display-aware
processing and GPU-accelerated texture compression. With display-aware
processing, only the currently visible image tiles are fetched and
aligned on-the-fly, reducing memory bandwidth and minimizing the need
for time-consuming global pre-processing. Our novel texture compression
scheme for GPUs is tailored for quick browsing of image stacks. We
evaluate the usability of our viewer for two histology applications:
digital pathology and visualization of neural structure at
nanoscale-resolution in serial electron micrographs. expand
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Articulated Planar Reformation for Change Visualization in Small Animal Imaging |
|
Peter Kok,
Martin Baiker,
Emile A. Hendriks,
Frits H. Post,
Jouke Dijkstra,
Clemens W. G. M. Lowik,
Boudewijn P. F. Lelieveldt,
Charl P. Botha
|
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Pages: 1396-1404 |
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doi>10.1109/TVCG.2010.134 |
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Full text available:
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The
analysis of multi-timepoint whole-body small animal CT data is greatly
complicated by the varying posture of the subjectat different
timepoints. Due to these variations, correctly relating and comparing
corresponding regions of interest is challenging.In ...
The
analysis of multi-timepoint whole-body small animal CT data is greatly
complicated by the varying posture of the subjectat different
timepoints. Due to these variations, correctly relating and comparing
corresponding regions of interest is challenging.In addition, occlusion
may prevent effective visualization of these regions of interest. To
address these problems, we have developeda method that fully
automatically maps the data to a standardized layout of sub-volumes,
based on an articulated atlas registration.We have dubbed this process
articulated planar reformation, or APR. A sub-volume can be
interactively selected for closer inspectionand can be compared with the
corresponding sub-volume at the other timepoints, employing a number of
different comparative visualization approaches. We provide an
additional tool that highlights possibly interesting areas based on the
change of bone densitybetween timepoints. Furthermore we allow
visualization of the local registration error, to give an indication of
the accuracy of theregistration. We have evaluated our approach on a
case that exhibits cancer-induced bone resorption. expand
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Volumetric Modeling in Laser BPH Therapy Simulation |
|
Nan Zhang,
Xiangmin Zhou,
Yunhe Shen,
Robert Sweet
|
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Pages: 1405-1412 |
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doi>10.1109/TVCG.2010.221 |
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Full text available:
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In
this paper, we introduce a novel application of volume modeling
techniques onlaser Benign Prostatic Hyperplasia (BPH) therapy
simulation.The core technique in our system is an algorithm for
simulating the tissue vaporization process by laser heating. ...
In
this paper, we introduce a novel application of volume modeling
techniques onlaser Benign Prostatic Hyperplasia (BPH) therapy
simulation.The core technique in our system is an algorithm for
simulating the tissue vaporization process by laser heating. Different
from classical volume CSG operations, our technique takes experimental
data as the guidance to determine the vaporization amount so that only a
specified amount of tissue is vaporized in each time. Our algorithm
uses a predictor-corrector strategy. First, we apply the classical CSG
algorithm on a tetrahedral grid based distance field to estimate the
vaporized tissue amount. Then, a volume-correction phase is applied on
the distance field. To improve the performance, we further propose
optimization approaches for efficient implementation. expand
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Scalable Multi-variate Analytics of Seismic and Satellite-based Observational Data |
|
Xiaoru Yuan,
He Xiao,
Hanqi Guo,
Peihong Guo,
Wesley Kendall,
Jian Huang,
Yongxian Zhang
|
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Pages: 1413-1420 |
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doi>10.1109/TVCG.2010.192 |
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Full text available:
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Over
the past few years, large human populations around the world have been
affected by an increase in significant seismic activities. For both
conducting basic scientific research and for setting critical government
policies, it is crucial to be able ...
Over
the past few years, large human populations around the world have been
affected by an increase in significant seismic activities. For both
conducting basic scientific research and for setting critical government
policies, it is crucial to be able to explore and understand seismic
and geographical information obtained through all scientific
instruments. In this work, we present a visual analytics system that
enables explorative visualization of seismic data together with
satellite-based observational data, and introduce a suite of visual
analytical tools. Seismic and satellite data are integrated temporally
and spatially. Users can select temporal ;and spatial ranges to zoom in
on specific seismic events, as well as to inspect changes both during
and after the events. Tools for designing high dimensional transfer
functions have been developed to enable efficient and intuitive
comprehension of the multi-modal data. Spread-sheet style comparisons
are used for data drill-down as well as presentation. Comparisons
between distinct seismic events are also provided for characterizing
event-wise differences. Our system has been designed for scalability in
terms of data size, complexity (i.e. number of modalities), and varying
form factors of display environments. expand
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Noodles: A Tool for Visualization of Numerical Weather Model Ensemble Uncertainty |
|
Jibonananda Sanyal,
Song Zhang,
Jamie Dyer,
Andrew Mercer,
Philip Amburn,
Robert Moorhead
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Pages: 1421-1430 |
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doi>10.1109/TVCG.2010.181 |
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Full text available:
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Numerical
weather prediction ensembles are routinely used for operational weather
forecasting. The members of these ensembles are individual simulations
with either slightly perturbed initial conditions or different model
parameterizations, or occasionally ...
Numerical
weather prediction ensembles are routinely used for operational weather
forecasting. The members of these ensembles are individual simulations
with either slightly perturbed initial conditions or different model
parameterizations, or occasionally both. Multi-member ensemble output is
usually large, multivariate, and challenging to interpret
interactively. Forecast meteorologists are interested in understanding
the uncertainties associated with numerical weather prediction;
specifically variability between the ensemble members. Currently,
visualization of ensemble members is mostly accomplished through
spaghetti plots of a single mid-troposphere pressure surface height
contour. In order to explore new uncertainty visualization methods, the
Weather Research and Forecasting (WRF) model was used to create a
48-hour, 18 member parameterization ensemble of the 13 March 1993
"Superstorm". A tool was designed to interactively explore the ensemble
uncertainty of three important weather variables: water-vapor mixing
ratio, perturbation potential temperature, and perturbation pressure.
Uncertainty was quantified using individual ensemble member standard
deviation, inter-quartile range, and the width of the 95% confidence
interval. Bootstrapping was employed to overcome the dependence on
normality in the uncertainty metrics. A coordinated view of ribbon and
glyph-based uncertainty visualization, spaghetti plots, iso-pressure
colormaps, and data transect plots was provided to two meteorologists
for expert evaluation. They found it useful in assessing uncertainty in
the data, especially in finding outliers in the ensemble run and
therefore avoiding the WRF parameterizations that lead to these
outliers. Additionally, the meteorologists could identify spatial
regions where the uncertainty was significantly high, allowing for
identification of poorly simulated storm environments and physical
interpretation of these model issues. expand
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Analysis of Recurrent Patterns in Toroidal Magnetic Fields |
|
Allen Sanderson,
Guoning Chen,
Xavier Tricoche,
David Pugmire,
Scott Kruger,
Joshua Breslau
|
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Pages: 1431-1440 |
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doi>10.1109/TVCG.2010.133 |
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Full text available:
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In
the development of magnetic confinement fusion which will potentially
be a future source for low cost power, physicists must be able to
analyze the magnetic field that confines the burning plasma. While the
magnetic field can be described as a vector ...
In
the development of magnetic confinement fusion which will potentially
be a future source for low cost power, physicists must be able to
analyze the magnetic field that confines the burning plasma. While the
magnetic field can be described as a vector field, traditional
techniques for analyzing the field's topology cannot be used because of
its Hamiltonian nature. In this paper we describe a technique developed
as a collaboration between physicists and computer scientists that
determines the topology of a toroidal magnetic field using fieldlines
with near minimal lengths.More specifically, we analyze the Poincaré map
of the sampled fieldlines in a Poincaré section including identifying
critical points and other topological features of interest to
physicists.The technique has been deployed into an interactiveparallel
visualization tool which physicists are using to gain new insight into
simulations of magnetically confined burning plasmas. expand
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Interactive Visualization of Hyperspectral Images of Historical Documents |
|
Seon Joo Kim,
Shaojie Zhuo,
Fanbo Deng,
Chi-Wing Fu,
Michael Brown
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Pages: 1441-1448 |
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doi>10.1109/TVCG.2010.172 |
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Full text available:
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This
paper presents an interactive visualization tool tostudy and analyze
hyperspectral images (HSI) of historicaldocuments. This work is part of a
collaborative effort with theNationaal Archief of the Netherlands (NAN)
and Art Innovation, amanufacturer ...
This
paper presents an interactive visualization tool tostudy and analyze
hyperspectral images (HSI) of historicaldocuments. This work is part of a
collaborative effort with theNationaal Archief of the Netherlands (NAN)
and Art Innovation, amanufacturer of hyperspectral imaging hardware
designed for old andfragile documents. The NAN is actively capturing HSI
of historicaldocuments for use in a variety of tasks related to the
analysis andmanagement of archival collections, from ink and paper
analysis tomonitoring the effects of environmental aging. To assist
their work,we have developed a comprehensive visualization tool that
offers anassortment of visualization and analysis methods,
includinginteractive spectral selection, spectral similarity
analysis,time-varying data analysis and visualization, and selective
spectralband fusion. This paper describes our visualization software and
howit is used to facilitate the tasks needed by our
collaborators.Evaluation feedback from our collaborators on how this
tool benefitstheir work is included. expand
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Interactive
Visual Analysis of Multiple Simulation Runs Using the Simulation Model
View: Understanding and Tuning of an Electronic Unit Injector |
|
Kresimir Matkovic,
Denis Gracanin,
Mario Jelovic,
Andreas Ammer,
Alan Lez,
Helwig Hauser
|
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Pages: 1449-1457 |
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doi>10.1109/TVCG.2010.171 |
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Full text available:
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Multiple
simulation runs using the same simulation model with different values
of control parameters generate a large data set that captures the
behavior of the modeled phenomenon. However, there is a conceptual and
visual gap between the simulation ...
Multiple
simulation runs using the same simulation model with different values
of control parameters generate a large data set that captures the
behavior of the modeled phenomenon. However, there is a conceptual and
visual gap between the simulation model behavior and the data set that
makes data analysis more difficult. We propose a simulation model view
that helps to bridge that gap by visually combining the simulation model
description and the generated data. The simulation model view provides a
visual outline of the simulation process and the corresponding
simulation model. The view is integrated in a Coordinated Multiple Views
;(CMV) system. As the simulation model view provides a limited display
space, we use three levels of details. We explored the use of the
simulation model view, in close collaboration with a domain expert, to
understand and tune an electronic unit injector (EUI). We also developed
analysis procedures based on the view. The EUI is mostly used in heavy
duty Diesel engines. We were mainly interested in understanding the
model and how to tune it for three different operation modes: low
emission, low consumption, and high power. Very positive feedback from
the domain expert shows that the use of the simulation model view and
the corresponding ;analysis procedures within a CMV system represents an
effective technique for interactive visual analysis of multiple
simulation runs. expand
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World Lines |
|
Jurgen Waser,
Raphael Fuchs,
Hrvoje Ribicic,
Benjamin Schindler,
Gunther Bloschl,
Eduard Groller
|
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Pages: 1458-1467 |
|
doi>10.1109/TVCG.2010.223 |
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Full text available:
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In
this paper we present World Lines as a novel interactive visualization
that provides complete control over multiple heterogeneous simulation
runs. In many application areas, decisions can only be made by exploring
alternative scenarios. The goal of ...
In
this paper we present World Lines as a novel interactive visualization
that provides complete control over multiple heterogeneous simulation
runs. In many application areas, decisions can only be made by exploring
alternative scenarios. The goal of the suggested approach is to support
users in this decision making process. In this setting, the data domain
is extended to a set of alternative worlds where only one outcome will
actually happen. World Lines integrate simulation, visualization and
computational steering into a single unified system that is capable of
dealing with the extended solution space. World Lines represent
simulation runs as causally connected tracks that share a common time
axis. This setup enables users to interfere and add new information
quickly. A World Line is introduced as a visual combination of user
events and their effects in order to present a possible future. To
quickly find the most attractive outcome, we suggest World Lines as the
governing component in a system of multiple linked views and a
simulation component. World Lines employ linking and brushing to enable
comparative visual analysis of multiple simulations in linked views.
Analysis results can be mapped to various visual variables that World
Lines provide in order to highlight the most compelling solutions. To
demonstrate this technique we present a flooding scenario and show the
usefulness of the integrated approach to support informed decision
making. expand
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Result-Driven Exploration of Simulation Parameter Spaces for Visual Effects Design |
|
Stefan Bruckner,
Torsten Moller
|
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Pages: 1468-1476 |
|
doi>10.1109/TVCG.2010.190 |
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Full text available:
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Graphics
artists commonly employ physically-based simulation for the generation
of effects such as smoke, explosions, and similar phenomena. The task of
finding the correct parameters for a desired result, however, is
difficult and time-consuming as ...
Graphics
artists commonly employ physically-based simulation for the generation
of effects such as smoke, explosions, and similar phenomena. The task of
finding the correct parameters for a desired result, however, is
difficult and time-consuming as current tools provide little to no
guidance. In this paper, we present a new approach for the visual
exploration of such parameter spaces. Given a three-dimensional scene
description, we utilize sampling and spatio-temporal clustering
techniques to generate a concise overview of the achievable variations
and their temporal evolution. Our visualization system then allows the
user to explore the simulation space in a goal-oriented manner.
Animation sequences with a set of desired characteristics can be
composed using a novel search-by-example approach and interactive direct
volume rendering is employed to provide instant visual feedback. expand
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Visual Optimality and Stability Analysis of 3DCT Scan Positions |
|
Artem Amirkhanov,
Christoph Heinzl,
Michael Reiter,
Eduard Groller
|
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Pages: 1477-1486 |
|
doi>10.1109/TVCG.2010.214 |
|
Full text available:
Publisher Site
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Industrial
cone-beam X-Ray computed tomography (CT) systems often face problems
due to artifacts caused by a bad placement of the specimen on the rotary
plate. This paper presents a visual-analysis tool for CT systems, which
provides a simulation-based ...
Industrial
cone-beam X-Ray computed tomography (CT) systems often face problems
due to artifacts caused by a bad placement of the specimen on the rotary
plate. This paper presents a visual-analysis tool for CT systems, which
provides a simulation-based preview and estimates artifacts and
deviations of a specimen's placement using the corresponding 3D
geometrical surface model as input. The presented tool identifies
potentially good or bad placements of a specimen and regions of a
specimen, which cause the major portion of artefacts. The tool can be
used for a preliminary analysis of the specimen before CT scanning, in
order to determine the optimal way of placing the object. The analysis
includes: penetration lengths, placement stability and an investigation
in Radon space. Novel visualization techniques are applied to the
simulation data. A stability widget is presented for determining the
placement parameters' robustness. The performance and the comparison of
results provided by the tool compared with real world data is
demonstrated using two specimens. expand
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Pre-Integrated Volume Rendering with Non-Linear Gradient Interpolation |
|
Amel Guetat,
Alexandre Ancel,
Stephane Marchesin,
Jean-Michel Dischler
|
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Pages: 1487-1494 |
|
doi>10.1109/TVCG.2010.187 |
|
Full text available:
Publisher Site
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Shading
is an important feature for the comprehension of volume datasets, but
is difficult to implement accurately. Current techniques based on
pre-integrated direct volume rendering approximate the volume rendering
integral by ignoring non-linear gradient ...
Shading
is an important feature for the comprehension of volume datasets, but
is difficult to implement accurately. Current techniques based on
pre-integrated direct volume rendering approximate the volume rendering
integral by ignoring non-linear gradient variations between front and
back samples, which might result in cumulated shading errors when
gradient variations are important and / or when the illumination
function features high frequencies. In this paper, we explore a simple
approach for pre-integrated volume rendering with non-linear gradient
interpolation between front and back samples. We consider that the
gradient smoothly varies along a quadratic curve instead of a segment
in-between consecutive samples. This not only allows us to compute more
accurate shaded pre-integrated look-up tables, but also allows us to
more efficiently process shading amplifying effects, based on gradient
filtering. An interesting property is that the pre-integration tables we
use remain two-dimensional as for usual pre-integrated classification.
We conduct experiments using a full hardware approach with the
Blinn-Phong illumination model as well as with a non-photorealistic
illumination model. expand
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Gradient Estimation Revitalized |
|
Usman Alim,
Torsten Moller,
Laurent Condat
|
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Pages: 1495-1504 |
|
doi>10.1109/TVCG.2010.160 |
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Full text available:
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We
investigate the use of a Fourier-domain derivative error kernel to
quantify the error incurred while estimating the gradient of a function
from scalar point samples on a regular lattice. We use the error kernel
to show that gradient reconstruction ...
We
investigate the use of a Fourier-domain derivative error kernel to
quantify the error incurred while estimating the gradient of a function
from scalar point samples on a regular lattice. We use the error kernel
to show that gradient reconstruction quality is significantly enhanced
merely by shifting the reconstruction kernel to the centers of the
principal lattice directions. Additionally, we exploit the algebraic
similarities between the scalar and derivative error kernels to design
asymptotically optimal gradient estimation filters that can be factored
into an infinite impulse response interpolation prefilter and a finite
impulse response directional derivative filter. This leads to a
significant performance gain both in terms of accuracy and computational
efficiency. The interpolation prefilter provides an accurate scalar
approximation and can be re-used to cheaply compute directional
derivatives on-the-fly without the need to store gradients. We
demonstrate the impact of our filters in the context of volume rendering
of scalar data sampled on the Cartesian and Body-Centered Cubic
lattices. Our results rival those obtained from other competitive
gradient estimation methods while incurring no additional computational
or storage overhead. expand
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Direct Interval Volume Visualization |
|
Marco Ament,
Daniel Weiskopf,
Hamish Carr
|
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Pages: 1505-1514 |
|
doi>10.1109/TVCG.2010.145 |
|
Full text available:
Publisher Site
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We
extend direct volume rendering with a unified model for generalized
isosurfaces, also called interval volumes, allowing a wider spectrum of
visual classification. We generalize the concept of scale-invariant
opacity—typical for isosurface rendering—to ...
We
extend direct volume rendering with a unified model for generalized
isosurfaces, also called interval volumes, allowing a wider spectrum of
visual classification. We generalize the concept of scale-invariant
opacity—typical for isosurface rendering—to semi-transparent interval
volumes. Scale-invariant rendering is independent of physical space
dimensions and therefore directly facilitates the analysis of data
characteristics. Our model represents sharp isosurfaces as limits of
interval volumes and combines them with features of direct volume
rendering. Our objective is accurate rendering, guaranteeing that all
isosurfaces and interval volumes are visualized in a crack-free way with
correct spatial ordering. We achieve simultaneous direct and interval
volume rendering by extending preintegration and explicit peak finding
with data-driven splitting of ray integration and hybrid computation in
physical and data domains. Our algorithm is suitable for efficient
parallel processing for interactive applications as demonstrated by our
CUDA implementation. expand
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VDVR: Verifiable Volume Visualization of Projection-Based Data |
|
Ziyi Zheng,
Wei Xu,
Klaus Mueller
|
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Pages: 1515-1524 |
|
doi>10.1109/TVCG.2010.211 |
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Full text available:
Publisher Site
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Practical
volume visualization pipelines are never without compromises and
errors. A delicate and often-studied component is the interpolation of
off-grid samples, where aliasing can lead to misleading artifacts and
blurring, potentially hiding fine ...
Practical
volume visualization pipelines are never without compromises and
errors. A delicate and often-studied component is the interpolation of
off-grid samples, where aliasing can lead to misleading artifacts and
blurring, potentially hiding fine details of critical importance. The
verifiable visualization framework we describe aims to account for these
errors directly in the volume generation stage, and we specifically
target volumetric data obtained via computed tomography (CT)
reconstruction. In this case the raw data are the X-ray projections
obtained from the scanner and the volume data generation process is the
CT algorithm. Our framework informs the CT reconstruction process of the
specific filter intended for interpolation in the subsequent
visualization process, and this in turn ensures an accurate
interpolation there at a set tolerance. Here, we focus on fast trilinear
interpolation in conjunction with an octree-type mixed resolution
volume representation without T-junctions. Efficient rendering is
achieved by a space-efficient and locality-optimized representation,
which can straightforwardly exploit fast fixed-function pipelines on
GPUs. expand
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Fast High-Quality Volume Ray Casting with Virtual Samplings |
|
Byeonghun Lee,
Jihye Yun,
Jinwook Seo,
Byonghyo Shim,
Yeong-Gil Shin,
Bohyoung Kim
|
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Pages: 1525-1532 |
|
doi>10.1109/TVCG.2010.155 |
|
Full text available:
Publisher Site
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Volume
ray-casting with a higher order reconstruction filter and/or a higher
sampling rate has been adopted in direct volume rendering frameworks to
provide a smooth reconstruction of the volume scalar and/or to reduce
artifacts when the combined frequency ...
Volume
ray-casting with a higher order reconstruction filter and/or a higher
sampling rate has been adopted in direct volume rendering frameworks to
provide a smooth reconstruction of the volume scalar and/or to reduce
artifacts when the combined frequency of the volume and transfer
function is high. While it enables high-quality volume rendering, it
cannot support interactive rendering due to its high computational cost.
In this paper, we propose a fast high-quality volume ray-casting
algorithm which effectively increases the sampling rate. While a ray
traverses the volume, intensity values are uniformly reconstructed using
a high-order convolution filter. Additional samplings, referred to as
virtual samplings, are carried out within a ray segment from a cubic
spline curve interpolating those uniformly reconstructed intensities.
These virtual samplings are performed by evaluating the polynomial
function of the cubic spline curve via simple arithmetic operations. The
min max blocks are refined accordingly for accurate empty space
skipping in the proposed method. Experimental results demonstrate that
the proposed algorithm, also exploiting fast cubic texture filtering
supported by programmable GPUs, offers renderings as good as a
conventional ray-casting algorithm using high-order reconstruction
filtering at the same sampling rate, while delivering 2.5x to 3.3x
rendering speed-up. expand
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Efficient High-Quality Volume Rendering of SPH Data |
|
Roland Fraedrich,
Stefan Auer,
Rudiger Westermann
|
|
Pages: 1533-1540 |
|
doi>10.1109/TVCG.2010.148 |
|
Full text available:
Publisher Site
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High
quality volume rendering of SPH data requires a complex order-dependent
resampling of particle quantities along the view rays. In this paper we
present an efficient approach to perform this task using a novel
view-space discretization of the simulation ...
High
quality volume rendering of SPH data requires a complex order-dependent
resampling of particle quantities along the view rays. In this paper we
present an efficient approach to perform this task using a novel
view-space discretization of the simulation domain. Our method draws
upon recent work on GPU-based particle voxelization for the efficient
resampling of particles into uniform grids. We propose a new technique
that leverages a perspective grid to adaptively discretize the
view-volume, giving rise to a continuous level-of-detail sampling
structure and reducing memory requirements compared to a uniform grid.
In combination with a level-of-detail representation of the particle
set, the perspective grid allows effectively reducing the amount of
primitives to be processed at run-time. We demonstrate the quality and
performance of our method for the rendering of fluid and gas dynamics
SPH simulations consisting of many millions of particles. expand
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Fast, Memory-Efficient Cell Location in Unstructured Grids for Visualization |
|
Christoph Garth,
Kenneth I. Joy
|
|
Pages: 1541-1550 |
|
doi>10.1109/TVCG.2010.156 |
|
Full text available:
Publisher Site
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|
Applying
certain visualization techniques to datasets described on unstructured
grids requires the interpolation of variables of interest at arbitrary
locations within the dataset's domain of definition. Typical solutions
to the problem of finding the ...
Applying
certain visualization techniques to datasets described on unstructured
grids requires the interpolation of variables of interest at arbitrary
locations within the dataset's domain of definition. Typical solutions
to the problem of finding the grid element enclosing a given
interpolation point make use of a variety of spatial subdivision
schemes. However, existing solutions are memory- intensive, do not scale
well to large grids, or do not work reliably on grids describing
complex geometries. In this paper, we propose a data structure and
associated construction algorithm for fast cell location in unstructured
grids, and apply it to the interpolation problem. Based on the concept
of bounding interval hierarchies, the proposed approach is
memory-efficient, fast and numerically robust. We examine the
performance characteristics of the proposed approach and compare it to
existing approaches using a number of benchmark problems related to
vector field visualization. Furthermore, we demonstrate that our
approach can successfully accommodate large datasets, and discuss
application to visualization on both CPUs and GPUs. expand
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Visualization by Proxy: A Novel Framework for Deferred Interaction with Volume Data |
|
Anna Tikhonova,
Carlos D. Correa,
Kwan-Liu Ma
|
|
Pages: 1551-1559 |
|
doi>10.1109/TVCG.2010.215 |
|
Full text available:
Publisher Site
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Interactivity
is key to exploration of volume data. Interactivity may be hindered due
to many factors, e.g. large data size,high resolution or complexity of a
data set, or an expensive rendering algorithm. We present a novel
framework for visualizing ...
Interactivity
is key to exploration of volume data. Interactivity may be hindered due
to many factors, e.g. large data size,high resolution or complexity of a
data set, or an expensive rendering algorithm. We present a novel
framework for visualizing volumedata that enables interactive
exploration using proxy images, without accessing the original 3D data.
Data exploration using directvolume rendering requires multiple (often
redundant) accesses to possibly large amounts of data. The notion of
visualization by proxyrelies on the ability to defer operations
traditionally used for exploring 3D data to a more suitable intermediate
representation forinteraction - proxy images. Such operations include
view changes, transfer function exploration, and relighting. While
previous workhas addressed specific interaction needs, we provide a
complete solution that enables real-time interaction with large data
sets andhas low hardware and storage requirements. expand
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Interactive Vector Field Feature Identification |
|
Joel Daniels II,
Erik W. Anderson,
Luis Gustavo Nonato,
Claudio T. Silva
|
|
Pages: 1560-1568 |
|
doi>10.1109/TVCG.2010.170 |
|
Full text available:
Publisher Site
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We
introduce a flexible technique for interactive exploration of vector
field data through classification derived from userspecified feature
templates. Our method is founded on the observation that, while similar
features within the vector field may ...
We
introduce a flexible technique for interactive exploration of vector
field data through classification derived from userspecified feature
templates. Our method is founded on the observation that, while similar
features within the vector field may bespatially disparate, they share
similar neighborhood characteristics. Users generate feature-based
visualizations by interactivelyhighlighting well-accepted and domain
specific representative feature points. Feature exploration begins with
the computation ofattributes that describe the neighborhood of each
sample within the input vector field. Compilation of these attributes
forms a representation of the vector field samples in the attribute
space. We project the attribute points onto the canonical 2D plane to
enableinteractive exploration of the vector field using a painting
interface. The projection encodes the similarities between vector field
pointswithin the distances computed between their associated attribute
points. The proposed method is performed at interactive rates
forenhanced user experience and is completely flexible as showcased by
the simultaneous identification of diverse feature types. expand
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Interactive Separating Streak Surfaces |
|
Florian Ferstl,
Kai Burger,
Holger Theisel,
Rudiger Westermann
|
|
Pages: 1569-1577 |
|
doi>10.1109/TVCG.2010.169 |
|
Full text available:
Publisher Site
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Streak
surfaces are among the most important features to support 3D unsteady
flow exploration, but they are also among the computationally most
demanding. Furthermore, to enable a feature driven analysis of the flow,
one is mainly interested in streak ...
Streak
surfaces are among the most important features to support 3D unsteady
flow exploration, but they are also among the computationally most
demanding. Furthermore, to enable a feature driven analysis of the flow,
one is mainly interested in streak surfaces that show separation
profiles and thus detect unstable manifolds in the flow. The computation
of such separation surfaces requires to place seeding structures at the
separation locations and to let the structures move correspondingly to
these locations in the unsteady flow. Since only little knowledge exists
about the time evolution of separating streak surfaces, at this time,
an automated exploration of 3D unsteady flows using such surfaces is not
feasible. Therefore, in this paper we present an interactive approach
for the visual analysis of separating streak surfaces. Our method draws
upon recent work on the extraction of Lagrangian coherent structures
(LCS) and the real-time visualization of streak surfaces on the GPU. We
propose an interactive technique for computing ridges in the finite time
Lyapunov exponent (FTLE) field at each time step, and we use these
ridges as seeding structures to track streak surfaces in the
time-varying flow. By showing separation surfaces in combination with
particle trajectories, and by letting the user interactively change
seeding parameters such as particle density and position, visually
guided exploration of separation profiles in 3D is provided. To the best
of our knowledge, this is the first time that the reconstruction and
display of semantic separable surfaces in 3D unsteady flows can be
performed interactively, giving rise to new possibilities for gaining
insight into complex flow phenomena. expand
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View-Dependent Streamlines for 3D Vector Fields |
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Stephane Marchesin,
Cheng-Kai Chen,
Chris Ho,
Kwan-Liu Ma
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Pages: 1578-1586 |
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doi>10.1109/TVCG.2010.212 |
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This
paper introduces a new streamline placement and selection algorithm for
3D vector fields. Instead of considering the problem as a simpl feature
search in data space, we base our work on the observation that most
streamline fields generate a lot ...
This
paper introduces a new streamline placement and selection algorithm for
3D vector fields. Instead of considering the problem as a simpl feature
search in data space, we base our work on the observation that most
streamline fields generate a lot of self-occlusion which prevents proper
visualization. In order to avoid this issue, we approach the problem in
a view-dependent fashion and dynamically determine a set of streamlines
which contributes to data understanding without cluttering the view.
Since our technique couples flow characteristic criteria and
view-dependent streamline selection we are able achieve the best of both
worlds: relevant flow description and intelligible, uncluttered
pictures. We detail an efficient GPU implementation of our algorithm,
show comprehensive visual results on multiple datasets and compare our
method with existing flow depiction techniques. Our results show that
our technique greatly improves the readability of streamline
visualizations on different datasets without requiring user
intervention. expand
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Visualizing Flow Trajectories Using Locality-based Rendering and Warped Curve Plots |
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Chad Jones,
Kwan-Liu Ma
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Pages: 1587-1594 |
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doi>10.1109/TVCG.2010.218 |
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In
flow simulations the behavior and properties of particle trajectories
often depend on the physical geometry containedin the simulated
environment. Understanding the flow in and around the geometry itself is
an important part of analyzing the data.Previous ...
In
flow simulations the behavior and properties of particle trajectories
often depend on the physical geometry containedin the simulated
environment. Understanding the flow in and around the geometry itself is
an important part of analyzing the data.Previous work has often
utilized focus+context rendering techniques, with an emphasis on showing
trajectories while simplifyingor illustratively rendering the physical
areas. Our research instead emphasizes the local relationship between
particle paths andgeometry by using a projected multi-field
visualization technique. The correlation between a particle path and its
surrounding areais calculated on-the-fly and displayed in a
non-intrusive manner. In addition, we support visual exploration and
comparative analysisthrough the use of linked information visualization,
such as manipulatable curve plots and one-on-one similarity plots. Our
techniqueis demonstrated on particle trajectories from a groundwater
simulation and a computer room airflow simulation, where the flow
ofparticles is highly influenced by the dense geometry. expand
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Superquadric Glyphs for Symmetric Second-Order Tensors |
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Thomas Schultz,
Gordon L. Kindlmann
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Pages: 1595-1604 |
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doi>10.1109/TVCG.2010.199 |
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Symmetric
second-order tensor fields play a central role in scientific and
biomedical studies as well as in image analysis and feature-extraction
methods. The utility of displaying tensor field samples has driven the
development of visualization techniques ...
Symmetric
second-order tensor fields play a central role in scientific and
biomedical studies as well as in image analysis and feature-extraction
methods. The utility of displaying tensor field samples has driven the
development of visualization techniques that encode the tensor shape and
orientation into the geometry of a tensor glyph. With some exceptions,
these methods work only for positive-definite tensors (i.e. having
positive eigenvalues, such as diffusion tensors). We expand the scope of
tensor glyphs to all symmetric second-order tensors in two and three
dimensions, gracefully and unambiguously depicting any combination of
positive and negative eigenvalues. We generalize a previous method of
superquadric glyphs for positive-definite tensors by drawing upon a
larger portion of the superquadric shape space, supplemented with a
coloring that indicates the quadratic form (including eigenvalue sign).
We show that encoding arbitrary eigenvalue magnitudes requires design
choices that differ fundamentally from those in previous work on
traceless tensors that arise in the study of liquid crystals. Our method
starts with a design of 2-D tensor glyphs guided by principles of
scale-preservation and symmetry, and creates 3-D glyphs that include the
2-D glyphs in their axis-aligned cross-sections. A key ingredient of
our method is a novel way of mapping from the shape space of
three-dimensional symmetric second-order tensors to the unit square. We
apply our new glyphs to stress tensors from mechanics, geometry tensors
and Hessians from image analysis, and rate-of-deformation tensors in
computational fluid dynamics. expand
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TanGeoMS: Tangible Geospatial Modeling System |
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Laura Tateosian,
Helena Mitasova,
Brendan Harmon,
Brent Fogleman,
Katherine Weaver,
Russel Harmon
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Pages: 1605-1612 |
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doi>10.1109/TVCG.2010.202 |
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We
present TanGeoMS, a tangible geospatial modeling visualization system
that couples a laser scanner, projector, and a flexible physical
three-dimensional model with a standard geospatial information system
(GIS) to create a tangible user interface ...
We
present TanGeoMS, a tangible geospatial modeling visualization system
that couples a laser scanner, projector, and a flexible physical
three-dimensional model with a standard geospatial information system
(GIS) to create a tangible user interface for terrain data. TanGeoMS
projects an image of real-world data onto a physical terrain model.
Users can alter the topography of the model by modifying the clay
surface or placing additional objects on the surface. The modified model
is captured by an overhead laser scanner then imported into a GIS for
analysis and simulation of real-world processes. The results are
projected back onto the surface of the model providing feedback on the
impact of the modifications on terrain parameters and simulated
processes. Interaction with a physical model is highly intuitive,
allowing users to base initial design decisions on geospatial data, test
the impact of these decisions in GIS simulations, and use the feedback
to improve their design. We demonstrate the system on three
applications: investigating runoff management within a watershed,
assessing the impact of storm surge on barrier islands, and exploring
landscape rehabilitation in military training areas. expand
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FI3D: Direct-Touch Interaction for the Exploration of 3D Scientific Visualization Spaces |
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Lingyun Yu,
Pjotr Svetachov,
Petra Isenberg,
Maarten H. Everts,
Tobias Isenberg
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Pages: 1613-1622 |
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doi>10.1109/TVCG.2010.157 |
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We
present the design and evaluation of FI3D, a direct-touch data
exploration technique for 3D visualization spaces. The exploration of
three-dimensional data is core to many tasks and domains involving
scientific visualizations. Thus, effective data ...
We
present the design and evaluation of FI3D, a direct-touch data
exploration technique for 3D visualization spaces. The exploration of
three-dimensional data is core to many tasks and domains involving
scientific visualizations. Thus, effective data navigation techniques
are essential to enable comprehension, understanding, and analysis of
the information space. While evidence exists that touch can provide
higher-bandwidth input, somesthetic information that is valuable when
interacting with virtual worlds, and awareness when working in
collaboration, scientific data exploration in 3D poses unique challenges
to the development of effective data manipulations. We present a
technique that provides touch interaction with 3D scientific data spaces
in 7 DOF. This interaction does not require the presence of dedicated
objects to constrain the mapping, a design decision important for many
scientific datasets such as particle simulations in astronomy or
physics. We report on an evaluation that compares the technique to
conventional mouse-based interaction. Our results show that touch
interaction is competitive in interaction speed for translation and
integrated interaction, is easy to learn and use, and is preferred for
exploration and wayfinding tasks. To further explore the applicability
of our basic technique for other types of scientific visualizations we
present a second case study, adjusting the interaction to the
illustrative visualization of fiber tracts of the brain and the
manipulation of cutting planes in this context. expand
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A Scalable Distributed Paradigm for Multi-User Interaction with Tiled Rear Projection Display Walls |
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Pablo Roman,
Maxim Lazarov,
Aditi Majumder
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Pages: 1623-1632 |
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doi>10.1109/TVCG.2010.128 |
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We
present the first distributed paradigm for multiple users to interact
simultaneously with large tiled rear projection display walls. Unlike
earlier works, our paradigm allows easy scalability across different
applications, interaction modalities, ...
We
present the first distributed paradigm for multiple users to interact
simultaneously with large tiled rear projection display walls. Unlike
earlier works, our paradigm allows easy scalability across different
applications, interaction modalities, displays and users. The novelty of
the design lies in its distributed nature allowing well-compartmented,
application independent, and application specific modules. This enables
adapting to different 2D applications and interaction modalities easily
by changing a few application specific modules. We demonstrate four
challenging 2D applications on a nine projector display to demonstrate
the application scalability of our method: map visualization, virtual
graffiti, virtual bulletin board and an emergency management system. We
demonstrate the scalability of our method to multiple interaction
modalities by showing both gesture-based and laser-based user
interfaces. Finally, we improve earlier distributed methods to register
multiple projectors. Previous works need multiple patterns to identify
the neighbors, the configuration of the display and the registration
across multiple projectors in logarithmic time with respect to the
number of projectors in the display. We propose a new approach that
achieves this using a single pattern based on specially augmented QR
codes in constant time. Further, previous distributed registration
algorithms are prone to large misregistrations. We propose a novel
radially cascading geometric registration technique that yields
significantly better accuracy. Thus, our improvements allow a
significantly more efficient and accurate technique for distributed
self-registration of multi-projector display walls. expand
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Projector Placement Planning for High Quality Visualizations on Real-World Colored Objects |
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Alvin J. Law,
Daniel G. Aliaga,
Aditi Majumder
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Pages: 1633-1641 |
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doi>10.1109/TVCG.2010.189 |
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Many
visualization applications benefit from displaying content on
real-world objects rather than on a traditional display(e.g., a
monitor). This type of visualization display is achieved by projecting
precisely controlled illumination from multiple ...
Many
visualization applications benefit from displaying content on
real-world objects rather than on a traditional display(e.g., a
monitor). This type of visualization display is achieved by projecting
precisely controlled illumination from multiple projectorsonto the
real-world colored objects. For such a task, the placement of the
projectors is critical in assuring that the desiredvisualization is
possible. Using ad hoc projector placement may cause some appearances to
suffer from color shifting due toinsufficient projector light radiance
being exposed onto the physical surface. This leads to an incorrect
appearance and ultimately toa false and potentially misleading
visualization. In this paper, we present a framework to discover the
optimal position andorientation of the projectors for such
projection-based visualization displays. An optimal projector placement
should be able toachieve the desired visualization with minimal
projector light radiance. When determining optimal projector placement,
objectvisibility, surface reflectance properties, and projector-surface
distance and orientation need to be considered. We first formalize
atheory for appearance editing image formation and construct a
constrained linear system of equations that express when a desirednovel
appearance or visualization is possible given a geometric and surface
reflectance model of the physical surface. Then, weshow how to apply
this constrained system in an adaptive search to efficiently discover
the optimal projector placement whichachieves the desired appearance.
Constraints can be imposed on the maximum radiance allowed by the
projectors and theprojectors' placement to support specific goals of
various visualization applications. We perform several real-world and
simulatedappearance edits and expand
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VisWeek Capstone Address |
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Alexander S. Szalay
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Pages: xxv-xxvi |
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doi>10.1109/TVCG.2010.219 |
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Author Index and Cover Image Credits |
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Pages: xxvii-xxviii |
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doi>10.1109/TVCG.2010.135 |
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