@article{bruckner-2009-IVV, title = "Instant Volume Visualization using Maximum Intensity Difference Accumulation", author = "Stefan Bruckner and Eduard Gr\"{o}ller", year = "2009", abstract = "It has long been recognized that transfer function setup for Direct Volume Rendering (DVR) is crucial to its usability. However, the task of finding an appropriate transfer function is complex and time-consuming even for experts. Thus, in many practical applications simpler techniques which do not rely on complex transfer functions are employed. One common example is Maximum Intensity Projection (MIP) which depicts the maximum value along each viewing ray. In this paper, we introduce Maximum Intensity Difference Accumulation (MIDA), a new approach which combines the advantages of DVR and MIP. Like MIP, MIDA exploits common data characteristics and hence does not require complex transfer functions to generate good visualization results. It does, however, feature occlusion and shape cues similar to DVR. Furthermore, we show that MIDA – in addition to being a useful technique in its own right – can be used to smoothly transition between DVR and MIP in an intuitive manner. MIDA can be easily implemented using volume raycasting and achieves real-time performance on current graphics hardware.", month = jun, journal = "Computer Graphics Forum", volume = "28", number = "3", issn = "0167-7055", pages = "775--782", keywords = "illustrative visualization, maximum intensity projection, direct volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/bruckner-2009-IVV/", } @phdthesis{rautek-2009-vmv, title = "Semantic Visualization Mapping for Volume Illustration", author = "Peter Rautek", year = "2009", abstract = "Scientific visualization is the discipline of automatically rendering images from scientific data. Adequate visual abstractions are important to show relevant information in the data. Visual abstractions are a trade-off between showing detailed information and preventing visual overload. To use visual abstractions for the depiction of data, a mapping from data attributes to visual abstractions is needed. This mapping is called the visualization mapping. This thesis reviews the history of visual abstractions and visualizationmapping in the context of scientific visualization. Later a novel visual abstraction method called caricaturistic visualization is presented. The concept of exaggeration is the visual abstraction used for caricaturistic visualization. Principles from traditional caricatures are used to accentuate salient details of data while sparsely sketching the context. The visual abstractions described in this thesis are inspired by visual art and mostly by traditional illustration techniques. To make effective use of the recently developed visualizationmethods, that imitate illustration techniques, an expressive visualization mapping approach is required. In this thesis a visualization mapping method is investigated that makes explicit use of semantics to describe mappings from data attributes to visual abstractions. The semantic visualization mapping explicitly uses domain semantics and visual abstraction semantics to specify visualization rules. Illustrative visualization results are shown that are achieved with the semantic visualization mapping. The behavior of the automatically rendered interactive illustrations is specified using interaction-dependent visualization rules. Interactions like the change of the viewpoint, or the manipulation of a slicing plane are state of the art in volume visualization. In this thesis a method for more elaborate interaction techniques is presented. The behavior of the illustrations is specified with interaction-dependent rules that are integrated in the semantic visualization mapping approach.", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/rautek-2009-vmv/", } @article{Rautek-2008-IDS, title = "Interaction-Dependent Semantics for Illustrative Volume Rendering", author = "Peter Rautek and Stefan Bruckner and Eduard Gr\"{o}ller", year = "2008", abstract = "In traditional illustration the choice of appropriate styles and rendering techniques is guided by the intention of the artist. For illustrative volume visualizations it is difficult to specify the mapping between the 3D data and the visual representation that preserves the intention of the user. The semantic layers concept establishes this mapping with a linguistic formulation of rules that directly map data features to rendering styles. With semantic layers fuzzy logic is used to evaluate the user defined illustration rules in a preprocessing step. In this paper we introduce interaction-dependent rules that are evaluated for each frame and are therefore computationally more expensive. Enabling interaction-dependent rules, however, allows the use of a new class of semantics, resulting in more expressive interactive illustrations. We show that the evaluation of the fuzzy logic can be done on the graphics hardware enabling the efficient use of interaction-dependent semantics. Further we introduce the flat rendering mode and discuss how different rendering parameters are influenced by the rule base. Our approach provides high quality illustrative volume renderings at interactive frame rates, guided by the specification of illustration rules.", month = may, journal = "Computer Graphics Forum", volume = "27", number = "3", pages = "847--854", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Rautek-2008-IDS/", } @phdthesis{bruckner-2008-IIV, title = "Interactive Illustrative Volume Visualization", author = "Stefan Bruckner", year = "2008", abstract = "Illustrations are essential for the effective communication of complex subjects. Their production, however, is a difficult and expensive task. In recent years, three-dimensional imaging has become a vital tool not only in medical diagnosis and treatment planning, but also in many technical disciplines (e.g., material inspection), biology, and archeology. Modalities such as X-Ray Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) produce high-resolution volumetric scans on a daily basis. It seems counter-intuitive that even though such a wealth of data is available, the production of an illustration should still require a mainly manual and time-consuming process. This thesis is devoted to the computer-assisted generation of illustrations directly from volumetric data using advanced visualization techniques. The concept of a direct volume illustration system is introduced for this purpose. Instead of requiring an additional modeling step, this system allows the designer of an illustration to work directly on the measured data. Abstraction, a key component of traditional illustrations, is used in order to reduce visual clutter, emphasize important structures, and reveal hidden detail. Low-level abstraction techniques are concerned with the appearance of objects and allow flexible artistic shading of structures in volumetric data sets. High-level abstraction techniques control which objects are visible. For this purpose, novel methods for the generation of ghosted and exploded views are introduced. The visualization techniques presented in this thesis employ the features of current graphics hardware to achieve interactive performance. The resulting system allows the generation of expressive illustrations directly from volumetric data with applications in medical training, patient education, and scientific communication.", month = mar, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "volume rendering, illustrative visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/bruckner-2008-IIV/", } @inproceedings{ruiz-2008-SEV, title = "Similarity-based Exploded Views", author = "Marc Ruiz and Ivan Viola and Imma Boada and Stefan Bruckner and Miquel Feixas and Mateu Sbert", year = "2008", abstract = "Exploded views are often used in illustration to overcome the problem of occlusion when depicting complex structures. In this paper, we propose a volume visualization technique inspired by exploded views that partitions the volume into a number of parallel slabs and shows them apart from each other. The thickness of slabs is driven by the similarity between partitions. We use an information-theoretic technique for the generation of exploded views. First, the algorithm identifies the viewpoint from which the structure is the highest. Then, the partition of the volume into the most informative slabs for exploding is obtained using two complementary similarity-based strategies. The number of slabs and the similarity parameter are freely adjustable by the user.", booktitle = "Proceedings of Smart Graphics 2008", pages = "154--165", keywords = "volume visualization, illustrative visualization, exploded views", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/ruiz-2008-SEV/", } @misc{Rautek-2008-kav, title = "Visual Abstractions and Interaction Metaphors for Knowledge Assisted Volume Visualization", author = "Peter Rautek and Ivan Viola", year = "2008", abstract = "Extended abstract published at Knowledge-assisted Visualization Workshop (colocated with the IEEE Visualization 2008 conference): http://kav.cs.wright.edu/", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Rautek-2008-kav/", } @misc{Rautek-2008-VF, title = "Illustrative Visualization – New Technology or Useless Tautology?", author = "Peter Rautek and Stefan Bruckner and Eduard Gr\"{o}ller and Ivan Viola", year = "2008", abstract = "This article can be accessed online in the ACM SIGGRAPH, Computer Graphics Quarterly, Volume 42, Number 3: http://www.siggraph.org/publications/newsletter/volume-42-number-3/illustrative-visualization-2013-new-technology-or-useless-tautology", note = "online journal, without talk", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Rautek-2008-VF/", } @inproceedings{ruiz-2008-OVR, title = "Obscurance-based Volume Rendering Framework", author = "Marc Ruiz and Imma Boada and Ivan Viola and Stefan Bruckner and Miquel Feixas and Mateu Sbert", year = "2008", abstract = "Obscurances, from which ambient occlusion is a particular case, is a technology that produces natural-looking lighting effects in a faster way than global illumination. Its application in volume visualization is of special interest since it permits us to generate a high quality rendering at a low cost. In this paper, we propose an obscurance-based framework that allows us to obtain realistic and illustrative volume visualizations in an interactive manner. Obscurances can include color bleeding effects without additional cost. Moreover, we obtain a saliency map from the gradient of obscurances and we show its application to enhance volume visualization and to select the most salient views.", booktitle = "Proceedings of Volume Graphics 2008", keywords = "volume rendering, illustrative visualization, ambient occlusion", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/ruiz-2008-OVR/", } @article{bruckner-2007-EDF, title = "Enhancing Depth-Perception with Flexible Volumetric Halos", author = "Stefan Bruckner and Eduard Gr\"{o}ller", year = "2007", abstract = "Volumetric data commonly has high depth complexity which makes it difficult to judge spatial relationships accurately. There are many different ways to enhance depth perception, such as shading, contours, and shadows. Artists and illustrators frequently employ halos for this purpose. In this technique, regions surrounding the edges of certain structures are darkened or brightened which makes it easier to judge occlusion. Based on this concept, we present a flexible method for enhancing and highlighting structures of interest using GPU-based direct volume rendering. Our approach uses an interactively defined halo transfer function to classify structures of interest based on data value, direction, and position. A feature-preserving spreading algorithm is applied to distribute seed values to neighboring locations, generating a controllably smooth field of halo intensities. These halo intensities are then mapped to colors and opacities using a halo profile function. Our method can be used to annotate features at interactive frame rates.", month = oct, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "13", number = "6", pages = "1344--1351", keywords = "volume rendering, illustrative visualization, halos", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/bruckner-2007-EDF/", } @article{Rautek-2007-SLI, title = "Semantic Layers for Illustrative Volume Rendering", author = "Peter Rautek and Stefan Bruckner and Eduard Gr\"{o}ller", year = "2007", abstract = "Direct volume rendering techniques map volumetric attributes (e.g., density, gradient magnitude, etc.) to visual styles. Commonly this mapping is specified by a transfer function. The specification of transfer functions is a complex task and requires expert knowledge about the underlying rendering technique. In the case of multiple volumetric attributes and multiple visual styles the specification of the multi-dimensional transfer function becomes more challenging and non-intuitive. We present a novel methodology for the specification of a mapping from several volumetric attributes to multiple illustrative visual styles. We introduce semantic layers that allow a domain expert to specify the mapping in the natural language of the domain. A semantic layer defines the mapping of volumetric attributes to one visual style. Volumetric attributes and visual styles are represented as fuzzy sets. The mapping is specified by rules that are evaluated with fuzzy logic arithmetics. The user specifies the fuzzy sets and the rules without special knowledge about the underlying rendering technique. Semantic layers allow for a linguistic specification of the mapping from attributes to visual styles replacing the traditional transfer function specification.", month = oct, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "13", number = "6", note = "to be presented at IEEE Visualization 2007", pages = "1336--1343", keywords = "Illustrative Visualization, Volume Visualization, Focus+Context Techniques", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/Rautek-2007-SLI/", } @article{bruckner-2007-STF, title = "Style Transfer Functions for Illustrative Volume Rendering", author = "Stefan Bruckner and Eduard Gr\"{o}ller", year = "2007", abstract = "Illustrative volume visualization frequently employs non-photorealistic rendering techniques to enhance important features or to suppress unwanted details. However, it is difficult to integrate multiple non-photorealistic rendering approaches into a single framework due to great differences in the individual methods and their parameters. In this paper, we present the concept of style transfer functions. Our approach enables flexible data-driven illumination which goes beyond using the transfer function to just assign colors and opacities. An image-based lighting model uses sphere maps to represent non-photorealistic rendering styles. Style transfer functions allow us to combine a multitude of different shading styles in a single rendering. We extend this concept with a technique for curvature-controlled style contours and an illustrative transparency model. Our implementation of the presented methods allows interactive generation of high-quality volumetric illustrations.", month = sep, journal = "Computer Graphics Forum", volume = "26", number = "3", note = "Eurographics 2007 3rd Best Paper Award", pages = "715--724", keywords = "illustrative visualization, transfer functions, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/bruckner-2007-STF/", } @misc{Rautek-2007-O3D, title = "Caricaturistic Visualization of Deformation Data Based on High Density Point Clouds", author = "Peter Rautek and Alexander Reiterer and Eduard Gr\"{o}ller", year = "2007", abstract = "Modern deformation monitoring techniques offer possibilities to measure and analyze deformation processes in detail. There are various different sensor systems on the market that can be used in these application fields, each having specific features in terms of accuracy, robustness, user interaction, operational range, measurement speed and frequency, resolution, or other relevant parameters. The selection of an appropriate sensor system for a particular application is not trivial. In recent years research on image-based measurement systems and laser scanners has gained increasing interest – in many cases a combination of different sensors has advantages over a single-sensor system (e.g. different accuracy and reliability classes, different measurement range, etc.). The point clouds produced by such systems potentially consist of a vast number of points. One of the main problems concerning the analysis and interpretation of deformation measurements is the visualization of the data respectively of the underlying deformation. In this paper we present the application of the recently developed caricaturistic visualization method to deformation data based on high density point clouds. Caricaturistic visualization depicts the deformation data in an exaggerated way. The exaggeration of the deformation accents subtle deviations and supports the viewer for the correct interpretation of the underlying deformation. We show results for facade deformation data as well as for landslide data. ", booktitle = "8th Conference on Optical 3-D Measurement Techniques, Zurich, Switzerland", Conference date = "Poster presented at (2007-07-09--2007-07-12)", keywords = "Point Cloud, Deformation Measurement, Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/Rautek-2007-O3D/", } @misc{tut-vis-2007, title = "IEEE Visualization Tutorial on Illustrative Display and Interaction in Visualization", author = "Ivan Viola and Stefan Bruckner and Mario Costa Sousa and David Ebert and Carlos Correa", year = "2007", abstract = "The area of illustrative visualization is concerned with developing methods to enhance the depiction of scientific data based on principles founded in traditional illustration. The illustration community has century-long experience in adapting their techniques to human perceptual needs in order to generate an effective depiction which conveys the desired message. Thus, their methods can provide us with important insights into visualization problems. In this tutorial, the concepts in illustrative visualization are reviewed. An important aspect here is interaction: while traditional illustrations are commonly only presented as static images, computer-assisted visualization enables interactive exploration and manipulation of complex scientific data. Only by coupling illustrative visualization with effective interaction techniques its full potential can be exploited. The tutorial starts with a general introduction into the area of illustrative visualization. The concept of importance-driven visualization and its applications are presented. Then we proceed with a discussion how traditional abstraction techniques can be applied in an interactive context using importance-based methods. This ranges from low-level appearance to smart viewpoint-dependent visibility techniques such as cutaways or exploded views. Further advanced manipulation strategies are discussed in the third part. The use deformations to enhance visibility of certain features while providing context or to abstract the structure of a complex objects through direct interaction with the data is examined. As many of the presented methods rely on a separation of focus and context, i.e., the important structures in the data have been identified, the tutorial discusses approaches for selecting objects of interest in a three-dimensional environment using intuitive sketch-based interfaces. Since the effectiveness of a user-interface is heavily dependent on the previous knowledge of the user, the last part of the tutorial examines the concept of layering interfaces based on user expertise. Finally, the application of illustrative display and interaction techniques for non-traditional modalities such as mobile devices concludes the tutorial. IEEE Visualization 2007 Tutorial Page: http://vis.computer.org/vis2007/session/tutorials.html#t7 See also previous tutorials on Illustrative Visualization: IEEE Visualization 2006 Tutorial on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-vis-2006/ Eurographics 2006 Tutorial on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-eg-2006/ SIGGRAPH 2006 Course on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-siggraph-2006/ IEEE Visualization 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/Viola-vistutillustrativevis/ Eurographics 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/eg-tut2005-iv/ ", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/tut-vis-2007/", } @article{bruckner-2006-ICE, title = "Illustrative Context-Preserving Exploration of Volume Data", author = "Stefan Bruckner and S\"{o}ren Grimm and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2006", abstract = "In volume rendering it is very difficult to simultaneously visualize interior and exterior structures while preserving clear shape cues. Highly transparent transfer functions produce cluttered images with many overlapping structures, while clipping techniques completely remove possibly important context information. In this paper we present a new model for volume rendering, inspired by techniques from illustration. It provides a means of interactively inspecting the interior of a volumetric data set in a feature-driven way which retains context information. The context-preserving volume rendering model uses a function of shading intensity, gradient magnitude, distance to the eye point, and previously accumulated opacity to selectively reduce the opacity in less important data regions. It is controlled by two user-specified parameters. This new method represents an alternative to conventional clipping techniques, shares their easy and intuitive user control, but does not suffer from the drawback of missing context information.", month = nov, issn = "1077-2626", journal = "IEEE Transactions on Visualization and Computer Graphics", number = "6", volume = "12", pages = "1559--1569", keywords = "focus+context techniques, volume rendering, illustrative visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/bruckner-2006-ICE/", } @article{Rautek06Vis, title = "Caricaturistic Visualization", author = "Peter Rautek and Ivan Viola and Eduard Gr\"{o}ller", year = "2006", abstract = "Caricatures are pieces of art depicting persons or sociological conditions in a non-veridical way. In both cases caricatures are referring to a reference model. The deviations from the reference model are the characteristic features of the depicted subject. Good caricatures exaggerate the characteristics of a subject in order to accent them. The concept of caricaturistic visualization is based on the caricature metaphor. The aim of caricaturistic visualization is an illustrative depiction of characteristics of a given dataset by exaggerating deviations from the reference model. We present the general concept of caricaturistic visualization as well as a variety of examples. We investigate different visual representations for the depiction of caricatures. Further, we present the caricature matrix, a technique to make differences between datasets easily identifiable.", month = nov, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "12", number = "5", issn = "1077-2626", pages = "1085--1092", keywords = "Focus+Context Techniques, Volume Visualization, Illustrative Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/Rautek06Vis/", } @article{vis-foa, title = "Importance-Driven Focus of Attention", author = "Ivan Viola and Miquel Feixas and Mateu Sbert and Eduard Gr\"{o}ller", year = "2006", abstract = "This paper introduces a concept for automatic focusing on features within a volumetric data set. The user selects a focus, i.e., object of interest, from a set of pre-defined features. Our system automatically determines the most expressive view on this feature. A characteristic viewpoint is estimated by a novel information-theoretic framework which is based on the mutual information measure. Viewpoints change smoothly by switching the focus from one feature to another one. This mechanism is controlled by changes in the importance distribution among features in the volume. The highest importance is assigned to the feature in focus. Apart from viewpoint selection, the focusing mechanism also steers visual emphasis by assigning a visually more prominent representation. To allow a clear view on features that are normally occluded by other parts of the volume, the focusing for example incorporates cut-away views.", month = oct, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "12", number = "5", pages = "933--940", keywords = "illustrative visualization, interacting with volumetric datasets, optimal viewpoint estimation, focus+context techniques, volume visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/vis-foa/", } @article{bruckner-2006-EVV, title = "Exploded Views for Volume Data", author = "Stefan Bruckner and Eduard Gr\"{o}ller", year = "2006", abstract = "Exploded views are an illustration technique where an object is partitioned into several segments. These segments are displaced to reveal otherwise hidden detail. In this paper we apply the concept of exploded views to volumetric data in order to solve the general problem of occlusion. In many cases an object of interest is occluded by other structures. While transparency or cutaways can be used to reveal a focus object, these techniques remove parts of the context information. Exploded views, on the other hand, do not suffer from this drawback. Our approach employs a force-based model: the volume is divided into a part configuration controlled by a number of forces and constraints. The focus object exerts an explosion force causing the parts to arrange according to the given constraints. We show that this novel and flexible approach allows for a wide variety of explosion-based visualizations including view-dependent explosions. Furthermore, we present a high-quality GPU-based volume ray casting algorithm for exploded views which allows rendering and interaction at several frames per second.", month = sep, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "12", number = "5", issn = "1077-2626", pages = "1077--1084", keywords = "exploded views, illustrative visualization, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/bruckner-2006-EVV/", } @misc{tut-siggraph-2006, title = "SIGGRAPH Course Illustrative Visualization for Medicine and Science", author = "Mario Costa Sousa and David Ebert and Bruce Gooch and Ivan Viola and Stefan Bruckner and Bill Andrews and Don Stredney and Nikolai Svakhine", year = "2006", abstract = "Research and recent development in computer-generated illustration techniques within non-photorealistic rendering. The course concentrates specifically on illustration methods for computer-generated technical, scientific, medical, and interactive illustrations of both surface and volumetric data. It also presents the perspective of two medical illustrators on computerized illustration. ACM SIGGRAPH 2006 course page: http://www.siggraph.org/s2006/main.php?f=conference&p=courses&s=6 Further Information: http://pages.cpsc.ucalgary.ca/~mario/webpage/publ/courses.htm See also previous tutorials on Illustrative Visualization: IEEE Visualization 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/Viola-vistutillustrativevis/ Eurographics 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/eg-tut2005-iv/ ", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/tut-siggraph-2006/", } @misc{tut-eg-2006, title = "Eurographics Tutorial on Illustrative Visualization for Science and Medicine", author = "Ivan Viola and Mario Costa Sousa and David Ebert and Bernhard Preim and Bruce Gooch and Bill Andrews and Christian Tietjen", year = "2006", abstract = "This tutorial presents recent and important research and developments from academia in illustrative, nonphotorealistic rendering (NPR) focusing on its use for medical/science subjects. Lectures are organized within a comprehensive illustration framework, focusing on three main components: (a) Traditional and computerized illustration techniques and principles for Technical and Science Subjects, (b) Evaluation and Practical Use, (c) Viewing & Rendering. Presentation of topics is balanced between descriptions of traditional methods and practices, practical implementation motivated approaches and evaluation, and detailed descriptions and analysis of NPR techniques and algorithms. We begin with a lecture presenting an overview of traditional illustration in technical, science, and medical subjects followed by a description of the main components in a NPR pipeline for developing systems to help technical and science illustrators with their work. The tutorial progresses with an overview of the NPR used in illustration as well as approaches to evaluate their use and effectiveness. Following lectures describe the latest techniques in computerized illustration algorithms for scientific and medical data for both surface and volumetric data, covering techniques from silhouette enhancement to stippling, to cut-away viewing, labeling, and focus+context rendering. Each of the lectures also discusses practical issues in making these techniques interactive and their use for different application domains. Tutorial concludes with discussion on specific medical case studies where the illustrative visualization has been effectively applied. Eurographics 2006 tutorial page: http://www.cg.tuwien.ac.at/events/EG06/program-t1022.php See also previous tutorials on Illustrative Visualization: SIGGRAPH 2006 Course on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-siggraph-2006/ IEEE Visualization 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/Viola-vistutillustrativevis/ Eurographics 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/eg-tut2005-iv/", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/tut-eg-2006/", } @studentproject{Marek06, title = "Flowfield-driven Volume Deformation", author = "Stefan Marek", year = "2006", abstract = "The volumetric flow (compare optical flow in 2D) is defined as the change of the volume over time. We define the volumetric flow on a regular grid. At each voxel position on the grid, a vector is defined, which is the flow on this position. Between voxels the volumetric flow is defined by the trilinear interpolation of the surrounding voxels. The project is divided in three subtasks: The specification, the visualization and the categorization of the volumetric flow. The goals of this computer science project are the first two subtasks: the interactive specification and visualization of the volumetric flow. For documentation goto: http://www.cg.tuwien.ac.at/courses/projekte_old/vis/finished/SMarek/htmldoc/index.html", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/Marek06/", } @misc{tut-vis-2006, title = "IEEE Visualization Tutorial on Illustrative Visualization for Science and Medicine", author = "Ivan Viola and Mario Costa Sousa and David Ebert and Bill Andrews and Bruce Gooch and Stefan Bruckner and Bernhard Preim and Don Stredney and Nikolai Svakhine and Christian Tietjen", year = "2006", abstract = "This tutorial presents recent research and developments from academia in illustrative visualization focusing on its use for medical/science subjects. Lectures are organized within a comprehensive illustration framework, focusing on three main components: • Traditional and computerized illustration techniques and principles for technical and scientific subjects • Evaluation and practical use • Viewing & rendering Presentation of topics is balanced between descriptions of traditional methods and practices, practical implementation motivated approaches and evaluation, and detailed descriptions and analysis of illustrative techniques and algorithms. We begin in the morning with a lecture presenting an overview of traditional illustration for technical, scientific, and medical subjects. This is followed by a description of the main components in an illustrative visualization pipeline for developing systems to assist technical and scientific illustrators. The tutorial progresses with an overview of the techniques used in illustration as well as approaches to evaluate their use and effectiveness. The morning concludes with the start of the “viewing and rendering” section. The three lectures in this section describe the latest approaches in computerized illustration algorithms for scientific and medical data for both surface and volumetric data, covering techniques from silhouette enhancement to stippling, to cut-away viewing, labeling, and focus+context rendering. Each of the lectures also discusses practical issues in making these techniques interactive and their use for different application domains. The tutorial includes a trained medical illustrator discussing the principles/caveats/issues in using illustration techniques in real-world medical applications. This lecture will also describe an evaluation, from an illustrator’s point of view, of the use and quality of the techniques presented throughout the day. The tutorial concludes with discussion on specific medical case studies where illustrative visualization has been effectively applied. IEEE Visualization 2006 Tutorial Page: http://vis.computer.org/vis2006/session/tutorials.html#t3 See also previous tutorials on Illustrative Visualization: Eurographics 2006 Tutorial on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-eg-2006/ SIGGRAPH 2006 Course on Illustrative Visualization for Science and Medicine http://www.cg.tuwien.ac.at/research/publications/2006/tut-siggraph-2006/ IEEE Visualization 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/Viola-vistutillustrativevis/ Eurographics 2005 Tutorial on Illustrative Visualization http://www.cg.tuwien.ac.at/research/publications/2005/eg-tut2005-iv/ ", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/tut-vis-2006/", } @talk{viola-2006-FoA, title = "Focus of Attention for Volumetric Data Inspection", author = "Ivan Viola and Miquel Feixas and Mateu Sbert and Eduard Gr\"{o}ller", year = "2006", event = "Dagstuhl Seminar on Computational Aesthetics in Computer Graphics, Visualization, and Imaging", location = "Dagstuhl castle, Germany", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/viola-2006-FoA/", } @misc{viola-popular-article-2006, title = "Explodierende K\"{o}rper", author = "Michael Krassnitzer and Ivan Viola and Stefan Bruckner", year = "2006", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/viola-popular-article-2006/", } @talk{Rautek06VMLS, title = "Caricaturistic Visualization", author = "Peter Rautek", year = "2006", abstract = "For many applications of medicine and life science, data is gathered or measured to find and to analyze the characteristics of the investigated object. Characteristics of a dataset can be expressed as the deviations from the norm. These deviations traditionally are found and classified using statistical methods. In many cases the statistical models do not appropriately describe the underlying phenomenon. They are therefore unsuitable for the data of interest. In this case visualization can replace the statistical methods. Expressive visualizations guide the user to find characteristics. Further the user is enabled to analyze the deviations of a given dataset. Caricaturistic visualization is an expressive method tailored to depict the deviations in an exaggerated way. It is guided by the idea of caricatures which exaggerate the outstanding features of an object. A method for caricaturistic visualization is presented and its power is shown on different examples. Caricaturistic visualization assumes the existence of a reference model. In many applications an explicit reference model is not available. To overcome this limitation different datasets are compared to each other. This results in the Caricature matrix, a 2D matrix of caricaturistic visualizations. ", event = "Workshop on Visualization in Medicine and Life Sciences", location = "R\"{u}gen, Germany", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/Rautek06VMLS/", } @inproceedings{bruckner-2005-VIS, title = "VolumeShop: An Interactive System for Direct Volume Illustration", author = "Stefan Bruckner and Eduard Gr\"{o}ller", year = "2005", abstract = "Illustrations play a major role in the education process. Whether used to teach a surgical or radiologic procedure, to illustrate normal or aberrant anatomy, or to explain the functioning of a technical device, illustration significantly impacts learning. Although many specimens are readily available as volumetric data sets, particularly in medicine, illustrations are commonly produced manually as static images in a time-consuming process. Our goal is to create a fully dynamic three-dimensional illustration environment which directly operates on volume data. Single images have the aesthetic appeal of traditional illustrations, but can be interactively altered and explored. In this paper we present methods to realize such a system which combines artistic visual styles and expressive visualization techniques. We introduce a novel concept for direct multi-object volume visualization which allows control of the appearance of inter-penetrating objects via two-dimensional transfer functions. Furthermore, a unifying approach to efficiently integrate many non-photorealistic rendering models is presented. We discuss several illustrative concepts which can be realized by combining cutaways, ghosting, and selective deformation. Finally, we also propose a simple interface to specify objects of interest through three-dimensional volumetric painting. All presented methods are integrated into VolumeShop, an interactive hardware-accelerated application for direct volume illustration.", month = oct, isbn = "0780394623", location = "Minneapolis, USA", editor = "C. T. Silva, E. Gr\"{o}ller, H. Rushmeier", booktitle = "Proceedings of IEEE Visualization 2005", pages = "671--678", keywords = "focus+context techniques, illustrative visualization, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/bruckner-2005-VIS/", } @misc{bruckner-2005-vid, title = "VolumeShop: Interactive Direct Volume Illustration", author = "Stefan Bruckner and Ivan Viola and Eduard Gr\"{o}ller", year = "2005", abstract = "Illustrations play a major role in the education process. Whether used to teach a surgical or radiologic procedure, to illustrate normal or aberrant anatomy, or to explain the functioning of a technical device, illustration significantly impacts learning. Many specimen are readily available as volumetric data sets, particular in medicine. Illustrations, however, are commonly produced manually as static images in a time-consuming process. Our goal is to create a fully dynamic three-dimensional illustration environment which directly operates on volume data. Single images have the aesthetic appeal of traditional illustrations, but can be interactively altered and explored. We present methods to realize such a system which combines artistic visual styles and expressive visualization techniques. Our implementation exploits the latest generation of GPUs and, thus, is capable of handling commonly sized data sets at interactive frame rates. ", month = aug, booktitle = "ACM Siggraph 2005 DVD Proceedings (Technical Sketch)", keywords = "focus+context techniques, volume rendering, illustrative techniques", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/bruckner-2005-vid/", } @inproceedings{Viola-05-Smart, title = "Smart Visibility in Visualization", author = "Ivan Viola and Eduard Gr\"{o}ller", year = "2005", abstract = "In this paper we discuss expressive visualization techniques that smartly uncover the most important information in order to maximize the visual information of the underlying data. This is achieved through dynamic change in visual representations, through deformations, or through changing the spatial position of parts of the data. Such techniques originate from technical illustration and are called cut-away views, ghosted views, and exploded views. These illustrative techniques unveil the most important visual information by a high level of abstraction. The change in visual representation or spatial position is done in a way that is easily perceivable and the overall visual harmony is preserved.", month = may, isbn = "3905673274", location = "Girona, Spain", editor = "L. Neumann, M. Sbert, B. Gooch, W. Purgathofer", booktitle = "Proceedings of EG Workshop on Computational Aesthetics Computational Aesthetics in Graphics, Visualization and Imaging", pages = "209--216", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/Viola-05-Smart/", } @talk{diss-thesis-bratislava, title = "Importance-Driven Expressive Visualization", author = "Ivan Viola", year = "2005", abstract = "In this talk several expressive visualization techniques for volumetric data are presented. The key idea is to classify the underlying data according to its prominence on the resulting visualization by importance value. The importance property drives the visualization pipeline to emphasize the most prominent features and to suppress the less relevant ones. The suppression can be realized globally, so the whole object is suppressed, or locally. A local modulation generates cut-away and ghosted views because the suppression of less relevant features occurs only on the part where the occlusion of more important features appears. Features within the volumetric data are classified according to a new imension denoted as object importance. This property determines which structures should be readily discernible and which structures are less important. Next, for each feature various representations (levels of sparseness) from a dense to a sparse depiction are defined. Levels of sparseness define a spectrum of optical properties or rendering styles. The resulting image is generated by ray-casting and combining the intersected features proportional to their importance. An additional step to traditional volume rendering evaluates the areas of occlusion and assigns a particular level of sparseness. This step is denoted as importance compositing. Advanced schemes for importance compositing determine the resulting visibility of features and if the resulting visibility distribution does not correspond to the importance distribution different levels of sparseness are selected. The applicability of importance-driven visualization is demonstrated on several examples from medical diagnostics scenarios, flow visualization, and interactive illustrative visualization. ", event = "Dissertation Thesis Report", location = "Comenius University Bratislava, Slovakia", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/diss-thesis-bratislava/", } @talk{diss-thesis-siegen, title = "Importance-Driven Expressive Visualization", author = "Ivan Viola", year = "2005", abstract = "In this talk several expressive visualization techniques for volumetric data are presented. The key idea is to classify the underlying data according to its prominence on the resulting visualization by importance value. The importance property drives the visualization pipeline to emphasize the most prominent features and to suppress the less relevant ones. The suppression can be realized globally, so the whole object is suppressed, or locally. A local modulation generates cut-away and ghosted views because the suppression of less relevant features occurs only on the part where the occlusion of more important features appears. Features within the volumetric data are classified according to a new imension denoted as object importance. This property determines which structures should be readily discernible and which structures are less important. Next, for each feature various representations (levels of sparseness) from a dense to a sparse depiction are defined. Levels of sparseness define a spectrum of optical properties or rendering styles. The resulting image is generated by ray-casting and combining the intersected features proportional to their importance. An additional step to traditional volume rendering evaluates the areas of occlusion and assigns a particular level of sparseness. This step is denoted as importance compositing. Advanced schemes for importance compositing determine the resulting visibility of features and if the resulting visibility distribution does not correspond to the importance distribution different levels of sparseness are selected. The applicability of importance-driven visualization is demonstrated on several examples from medical diagnostics scenarios, flow visualization, and interactive illustrative visualization. ", event = "Dissertation Thesis Report", location = "University of Siegen, Germany", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/diss-thesis-siegen/", } @misc{Viola-vistutillustrativevis, title = "IEEE Visualization Tutorial on Illustrative Visualization", author = "Ivan Viola and Eduard Gr\"{o}ller and Katja B\"{u}hler and Markus Hadwiger and Bernhard Preim and David Ebert and Mario Costa Sousa and Don Stredney", year = "2005", abstract = "The tutorial presents state-of-the-art visualization techniques inspired by traditional technical and medical illustrations. Such techniques exploit the perception of the human visual system and provide effective visual abstractions to make the visualization clearly understandable. Visual emphasis and abstraction has been used for expressive presentation from prehistoric paintings to nowadays scientific and medical illustrations. Many of the expressive techniques used in art are adopted in computer graphics, and are denoted as illustrative or non-photorealistic rendering. Different stroke techniques, or brush properties express a particular level of abstraction. Feature emphasis or feature suppression is achieved by combining different abstraction levels in illustrative rendering. Challenges in visualization research are very large data visualization as well as multi-dimensional data visualization. To effectively convey the most important visual information there is a significant need for visual abstraction. For less relevant information the dedicated image space is reduced to enhance more prominent features. The discussed techniques in the context of scientic visualization are based on iso-surfaces and volume rendering. Apart from visual abstraction, i.e., illustrative representation, the visibility of prominent features can be achieved by illustrative visualization techniques such as cut-away views or ghosted views. The structures that occlude the most prominent information are suppressed in order to clearly see more interesting parts. A different smart way to provide information on the data is using exploded views or other types of deformation. Furthermore intuitive feature classification via 3D painting and manipulation with the classified data including label placement is presented. Discussed non-photorealistic and illustrative techniques from visualization and graphics are shown from the perspective as tools for illustrators from medicine, botany, archeology, and zoology. The limitations of existing NPR systems for science illustration are highlighted, and proposals for possible new directions are made. Illustrative visualization is demonstrated via application-specific tasks in medical visualization. An important aspect as compared to traditional medical illustrations is the interactivity and real-time manipulation of the acquired patient data. This can be very useful in anatomy education. Another application area is surgical planning which is demonstrated with two case studies: neck dissection and liver surgery planning.", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/Viola-vistutillustrativevis/", } @misc{eg-tut2005-iv, title = "Eurographics Tutorial on Illustrative Visualization", author = "Ivan Viola and Eduard Gr\"{o}ller and Katja B\"{u}hler and Markus Hadwiger and Bernhard Preim and David Ebert", year = "2005", abstract = "The tutorial presents state-of-the-art visualization techniques inspired by traditional technical and medical illustrations. Such techniques exploit the perception of the human visual system and provide effective visual abstractions to make the visualization clearly understandable. Visual emphasis and abstraction has been used for expressive presentation from prehistoric paintings to nowadays scientific and medical illustrations. Many of the expressive techniques used in art are adopted in computer graphics, and are denoted as illustrative or non-photorealistic rendering. Different stroke techniques, or brush properties express a particular level of abstraction. Feature emphasis or feature suppression is achieved by combining different abstraction levels in illustrative rendering. Challenges in visualization research are very large data visualization as well as multi-dimensional data visualization. To effectively convey the most important visual information there is a significant need for visual abstraction. For less relevant information the dedicated image space is reduced to enhance more prominent features. The discussed techniques in the context of scientific visualization are based on iso-surfaces and volume rendering. Apart from visual abstraction, i.e., illustrative representation, the visibility of prominent features can be achieved by illustrative visualization techniques such as cut-away views or ghosted views. The structures that occlude the most prominent information are suppressed in order to clearly see more interesting parts. Another smart way to provide information on the data is using exploded views or other types of deformation. Illustrative visualization is demonstrated via application-specific tasks in medical visualization. An important aspect as compared to traditional medical illustrations is the interactivity and real-time manipulation of the acquired patient data. This can be very useful in anatomy education. Another application area is surgical planning which is demonstrated with two case studies: neck dissection and liver surgery planning.", booktitle = "Tutorial Notes on Illustrative Visualization", publisher = "Eurographics", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/eg-tut2005-iv/", } @talk{bruckner-2005-AIV, title = "Applications of Illustrative Volume Visualization Techniques", author = "Stefan Bruckner", year = "2005", abstract = "Illustrative visualization deals with computer supported interactive and expressive visualizations through abstractions which are inspired by traditional illustrations. This talk covers two important aspects of illustrative visualization of volume data: exploration and communication. Exploration deals with techniques for the rapid visualization of data with limited or no prior knowledge about the nature and/or structure of the data. Communication, on the other hand, is concerned with conveying complex structures or relationships to individuals. The talk discusses recent approaches in both areas.", location = "Magdeburg, Germany", keywords = "exploration, illustrative visualization, communication", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/bruckner-2005-AIV/", } @talk{diss-thesis-magdeburg, title = "Importance-Driven Expressive Visualization", author = "Ivan Viola", year = "2005", abstract = "In this talk several expressive visualization techniques for volumetric data are presented. The key idea is to classify the underlying data according to its prominence on the resulting visualization by importance value. The importance property drives the visualization pipeline to emphasize the most prominent features and to suppress the less relevant ones. The suppression can be realized globally, so the whole object is suppressed, or locally. A local modulation generates cut-away and ghosted views because the suppression of less relevant features occurs only on the part where the occlusion of more important features appears. Features within the volumetric data are classified according to a new imension denoted as object importance. This property determines which structures should be readily discernible and which structures are less important. Next, for each feature various representations (levels of sparseness) from a dense to a sparse depiction are defined. Levels of sparseness define a spectrum of optical properties or rendering styles. The resulting image is generated by ray-casting and combining the intersected features proportional to their importance. An additional step to traditional volume rendering evaluates the areas of occlusion and assigns a particular level of sparseness. This step is denoted as importance compositing. Advanced schemes for importance compositing determine the resulting visibility of features and if the resulting visibility distribution does not correspond to the importance distribution different levels of sparseness are selected. The applicability of importance-driven visualization is demonstrated on several examples from medical diagnostics scenarios, flow visualization, and interactive illustrative visualization. ", event = "Dissertation Thesis Report", location = "University of Magdeburg, Germany", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/diss-thesis-magdeburg/", }