@article{mistelbauer-2013-cfa, title = "Vessel Visualization using Curvicircular Feature Aggregation", author = "Gabriel Mistelbauer and Anca Morar and Andrej Varchola and R\"{u}diger Schernthaner and Ivan Baclija and Arnold K\"{o}chl and Armin Kanitsar and Stefan Bruckner and Eduard Gr\"{o}ller", year = "2013", abstract = "Radiological investigations are common medical practice for the diagnosis of peripheral vascular diseases. Existing visualization methods such as Curved Planar Reformation (CPR) depict calcifications on vessel walls to determine if blood is still able to flow. While it is possible with conventional CPR methods to examine the whole vessel lumen by rotating around the centerline of a vessel, we propose Curvicircular Feature Aggregation (CFA), which aggregates these rotated images into a single view. By eliminating the need for rotation, vessels can be investigated by inspecting only one image. This method can be used as a guidance and visual analysis tool for treatment planning. We present applications of this technique in the medical domain and give feedback from radiologists.", month = jun, journal = "Computer Graphics Forum", volume = "32", number = "3", pages = "231--240", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/mistelbauer-2013-cfa/", } @inproceedings{haidacher_2010_statTF, title = "Volume Visualization based on Statistical Transfer-Function Spaces", author = "Martin Haidacher and Daniel Patel and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2010", abstract = "It is a difficult task to design transfer functions for noisy data. In traditional transfer-function spaces, data values of different materials overlap. In this paper we introduce a novel statistical transfer-function space which in the presence of noise, separates different materials in volume data sets. Our method adaptively estimates statistical properties, i.e. the mean value and the standard deviation, of the data values in the neighborhood of each sample point. These properties are used to define a transfer-function space which enables the distinction of different materials. Additionally, we present a novel approach for interacting with our new transfer-function space which enables the design of transfer functions based on statistical properties. Furthermore, we demonstrate that statistical information can be applied to enhance visual appearance in the rendering process. We compare the new method with 1D, 2D, and LH transfer functions to demonstrate its usefulness.", month = mar, booktitle = "Proceedings of the IEEE Pacific Visualization 2010", pages = "17--24", keywords = "transfer function, statistics, shading, noisy data, classification", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/haidacher_2010_statTF/", } @inproceedings{kohlmann-2009-cp, title = "Contextual Picking of Volumetric Structures", author = "Peter Kohlmann and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2009", month = may, isbn = "978-1-4244-4404-5", location = "Peking, China", editor = "Peter Eades, Thomas Ertl, Han-Wei Shen", booktitle = "Proceedings of the IEEE Pacific Visualization Symposium 2009", pages = "185--192", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/kohlmann-2009-cp/", } @techreport{TR-186-2-08-14, title = "Smart Linking of 2D and 3D Views in Medical Applications", author = "Peter Kohlmann and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2008", abstract = "This paper presents two techniques for the linking of 2D and 3D views in medical applications. Hereby, the goal is a better integration of 3D volume visualization into the diagnostic workflow. Until now, the main obstacle for a good integration is the time-consuming process to adjust various parameters. The LiveSync interaction metaphor is a new concept to synchronize 2D slice views and 3D volumetric views of medical data sets. A single intuitive picking interaction on anatomical structures which are detected in 2D slices results in an automatically generated 3D view. To further improve the integration contextual picking is presented as a method for the interactive identification of contextual interest points within volumetric data. Our results demonstrate how these techniques improve the efficiency to generate diagnostically relevant images and how contextual interest points can, e.g., facilitate the highlighting of relevant structures.", month = dec, number = "TR-186-2-08-14", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/TR-186-2-08-14/", } @inproceedings{haidacher-2008-vcbm, title = "Information-based Transfer Functions for Multimodal Visualization", author = "Martin Haidacher and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2008", abstract = "Transfer functions are an essential part of volume visualization. In multimodal visualization at least two values exist at every sample point. Additionally, other parameters, such as gradient magnitude, are often retrieved for each sample point. To find a good transfer function for this high number of parameters is challenging because of the complexity of this task. In this paper we present a general information-based approach for transfer function design in multimodal visualization which is independent of the used modality types. Based on information theory, the complex multi-dimensional transfer function space is fused to allow utilization of a well-known 2D transfer function with a single value and gradient magnitude as parameters. Additionally, a quantity is introduced which enables better separation of regions with complementary information. The benefit of the new method in contrast to other techniques is a transfer function space which is easy to understand and which provides a better separation of different tissues. The usability of the new approach is shown on examples of different modalities.", month = oct, isbn = "978-3-905674-13-2", publisher = "Eurographics Association", location = "Delft", issn = "2070-5778", editor = "C.P Botha, G. Kindlmann, W.J. Niessen, and B. Preim", booktitle = "VCBM ", pages = "101--108", keywords = "Multimodal Visualization, Transfer Function, Information Theory", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/haidacher-2008-vcbm/", } @inproceedings{bruckner-2008-IVV, title = "Integrating Volume Visualization Techniques Into Medical Applications", author = "Stefan Bruckner and Peter Kohlmann and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2008", abstract = "One of the main obstacles in integrating 3D volume visualization in the clinical workflow is the time-consuming process of adjusting parameters such as viewpoint, transfer functions, and clipping planes required to generate a diagnostically relevant image. Current applications therefore make scarce use of volume rendering and instead primarily employ 2D views generated through standard techniques such as multi-planar reconstruction (MPR). However, in many cases 3D renditions can supply additional useful information. This paper discusses ongoing work which aims to improve the integration of 3D visualization into the diagnostic workflow by automatically generating meaningful renditions based on minimal user interaction. A method for automatically generating 3D views for structures in 2D slices based on a single picking interaction is presented.", month = may, isbn = "978-1-4244-2002-5", location = "Paris, Frankreich", booktitle = "Proceedings of 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro", pages = "820--823", keywords = "viewpoint selection, medical visualization, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/bruckner-2008-IVV/", } @inproceedings{kohlmann-2008-lse, title = "LiveSync++: Enhancements of an Interaction Metaphor", author = "Peter Kohlmann and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2008", abstract = "The LiveSync interaction metaphor allows an efficient and non-intrusive integration of 2D and 3D visualizations in medical workstations. This is achieved by synchronizing the 2D slice view with the volumetric view. The synchronization is initiated by a simple picking on a structure of interest in the slice view. In this paper we present substantial enhancements of the existing concept to improve its usability. First, an efficient parametrization for the derived parameters is presented, which allows hierarchical refinement of the search space for good views. Second, the extraction of the feature of interest is performed in a way, which is adapting to the volumetric extent of the feature. The properties of the extracted features are utilized to adjust a predefined transfer function in a feature-enhancing manner. Third, a new interaction mode is presented, which allows the integration of more knowledge about the user-intended visualization, without increasing the interaction effort. Finally, a new clipping technique is integrated, which guarantees an unoccluded view on the structure of interest while keeping important contextual information.", month = may, location = "Windsor, Ontario, Canada", booktitle = "Proceedings of Graphics Interface 2008", pages = "81--88", keywords = "Viewpoint Selection, Linked Views, Medical Visualization, Smart Interaction", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/kohlmann-2008-lse/", } @article{kohlmann-2007-livesync, title = "LiveSync: Deformed Viewing Spheres for Knowledge-Based Navigation", author = "Peter Kohlmann and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2007", abstract = "Although real-time interactive volume rendering is available even for very large data sets, this visualization method is used quite rarely in the clinical practice. We suspect this is because it is very complicated and time consuming to adjust the parameters to achieve meaningful results. The clinician has to take care of the appropriate viewpoint, zooming, transfer function setup, clipping planes and other parameters. Because of this, most often only 2D slices of the data set are examined. Our work introduces LiveSync, a new concept to synchronize 2D slice views and volumetric views of medical data sets. Through intuitive picking actions on the slice, the users define the anatomical structures they are interested in. The 3D volumetric view is updated automatically with the goal that the users are provided with expressive result images. To achieve this live synchronization we use a minimal set of derived information without the need for segmented data sets or data-specific pre-computations. The components we consider are the picked point, slice view zoom, patient orientation, viewpoint history, local object shape and visibility. We introduce deformed viewing spheres which encode the viewpoint quality for the components. A combination of these deformed viewing spheres is used to estimate a good viewpoint. Our system provides the physician with synchronized views which help to gain deeper insight into the medical data with minimal user interaction.", month = oct, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "13", number = "6", note = "to be presented at IEEE Visualization 2007", pages = "1544--1551", keywords = "linked views, interaction, medical visualization, navigation, viewpoint selection", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/kohlmann-2007-livesync/", } @article{roos-2007-mcp, title = "Multipath Curved Planar Reformation of the Peripheral Arterial Tree in CT Angiography", author = "J Roos and Dominik Fleischmann and A Koechl and T Rakshe and Mat\'{u}s Straka and A Napoli and Armin Kanitsar and Milos Sramek and Eduard Gr\"{o}ller", year = "2007", month = jul, journal = "Journal Radiology", number = "1", volume = "244", pages = "281--290", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/roos-2007-mcp/", } @article{Kohlmann-2007-EBV, title = "Evaluation of a Bricked Volume Layout for a Medical Workstation based on Java", author = "Peter Kohlmann and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2007", abstract = "Volumes acquired for medical examination purposes are constantly increasing in size. For this reason, the computer’s memory is the limiting factor for visualizing the data. Bricking is a well-known concept used for rendering large data sets. The volume data is subdivided into smaller blocks to achieve better memory utilization. Until now, the vast majority of medical workstations use a linear volume layout. We implemented a bricked volume layout for such a workstation based on Java as required by our collaborative company partner to evaluate different common access patterns to the volume data. For rendering, we were mainly interested to see how the performance will differ from the traditional linear volume layout if we generate images of arbitrarily oriented slices via Multi-Planar Reformatting (MPR). Furthermore, we tested access patterns which are crucial for segmentation issues like a random access to data values and a simulated region growing. Our goal was to find out if it makes sense to change the volume layout of a medical workstation to benefit from bricking. We were also interested to identify the tasks where problems might occur if bricking is applied. Overall, our results show that it is feasible to use a bricked volume layout in the stringent context of a medical workstation implemented in Java.", month = jan, journal = "Journal of WSCG", volume = "15", number = "1-3", issn = "1213-6972", pages = "83--90", keywords = "MPR, Bricked Volume Layout, Medical Visualization, Medical Workstation", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/Kohlmann-2007-EBV/", } @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/", } @inproceedings{coto-2005-MAC, title = "MammoExplorer: An Advanced CAD Application for Breast DCE-MRI", author = "Ernesto Coto and S\"{o}ren Grimm and Stefan Bruckner and Eduard Gr\"{o}ller and Armin Kanitsar and Omaira Rodriguez", year = "2005", abstract = "Currently X-ray mammography is the most widely used method for early detection of breast cancer. However, the use of Dynamic Contrast Enhanced MRI (DCE-MRI) has gained wider attention, since it considerably improves tumor detection and classification by analyzing the flow of contrast agent within the breast tissue. In this paper we present MammoExplorer, a CAD application that combines advanced interaction, segmentation and visualization techniques to explore Breast DCE-MRI data. Our application uses Brushing and Linking, Two-level Volume Rendering, Importance-driven Volume Rendering, and False Color Maps. In addition, we present Enhancement Scatterplots, a novel graphical representation of DCE-MRI data, novel segmentation approaches, and a new way to explore time-varying CE-MRI data.", month = nov, isbn = "3898380688", location = "Erlangen, Germany", editor = "G. Greiner, J. Hornegger, H. Niemann, M. Stamminger", booktitle = "Proceedings of Vision, Modelling, and Visualization 2005", pages = "91--98", keywords = "CAD, Breast cancer, Contrast Enhanced MRI", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/coto-2005-MAC/", } @inproceedings{bruckner-2005-ICV, title = "Illustrative Context-Preserving Volume Rendering", author = "Stefan Bruckner and S\"{o}ren Grimm and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2005", abstract = "In volume rendering it is very difficult to simultaneously visualize interior and exterior structures while preserving clear shape cues. Very 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 that 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 = may, booktitle = "Proceedings of EuroVis 2005", pages = "69--76", keywords = "non-photorealistic techniques, focus+context techniques, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/bruckner-2005-ICV/", } @incollection{groeller-2005-dia, title = "Diagnostic Relevant Visualization of Vascular Structures ", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2005", abstract = "Traditional volume visualization techniques sometimes provide incomplete clinical information needed for applications in medical visualization. In the area of vascular visualization important features such as the lumen of a diseased vessel segment may not be visible. One way to display vascular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. Curved planar reformation (CPR) has proven to be an acceptable practical solution. We discuss four different methods to generate CPR images from single vessel segments: Projected CPR, stretched CPR, straightened CPR, and helical CPR. Furthermore we investigate three different methods for displaying vascular trees: Multi-path projected CPR, multi-path stretched CPR, and untangled CPR. The principle concept of each method is discussed and detailed information for the realization is given. In addition the properties, advantages and disadvantages of each method are summarized.", booktitle = "Scientific Visualization: The Visual Extraction of Knowledge from Data", editor = "G.-P. Bonneau, T. Ertl, G.M. Nielson", isbn = "3540260668", publisher = "Springer Verlag, Berlin", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/groeller-2005-dia/", } @article{viola-2005-imp, title = "Importance-Driven Feature Enhancement in Volume Visualization", author = "Ivan Viola and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2005", abstract = "This paper presents importance-driven feature enhancement as a technique for the automatic generation of cut-away and ghosted views out of volumetric data. The presented focus+context approach removes or suppresses less important parts of a scene to reveal more important underlying information. however, less important parts are fully visible in those regions, where important visual information is not lost, i.e., more relevant features are not occluded. Features within the volumetric data are first classified according to a new dimension 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 (importance compositing). The paper includes an extended discussion on several possible schemes for levels of sparseness specification. Furthermore different approaches to importance compositing are treated.", journal = "IEEE Transactions on Visualization and Computer Graphics", number = "4", volume = "11", pages = "408--418", keywords = "non-photorealistic techniques, view-dependent visualization, volume rendering, focus+context techniques, level-of-detail techniques", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/viola-2005-imp/", } @inproceedings{grimm-2004-memory, title = "Memory Efficient Acceleration Structures and Techniques for CPU-based Volume Raycasting of Large Data", author = "S\"{o}ren Grimm and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "Most CPU-based volume raycasting approaches achieve high performance by advanced memory layouts, space subdivision, and excessive pre-computing. Such approaches typically need an enormous amount of memory. They are limited to sizes which do not satisfy the medical data used in daily clinical routine. We present a new volume raycasting approach based on image-ordered raycasting with object-ordered processing, which is able to perform high-quality rendering of very large medical data in real-time on commodity computers. For large medical data such as computed tomographic (CT) angiography run-offs (512x512x1202) we achieve rendering times up to 2.5 fps on a commodity notebook. We achieve this by introducing a memory efficient acceleration technique for on-the-fly gradient estimation and a memory efficient hybrid removal and skipping technique of transparent regions. We employ quantized binary histograms, granular resolution octrees, and a cell invisibility cache. These acceleration structures require just a small extra storage of approximately 10%. ", month = oct, isbn = "0-7803-8781-3", editor = "D. Silver, T. Ertl, C. Silva", booktitle = "Proceedings IEEE/SIGGRAPH Symposium on Volume Visualization and Graphics", pages = "1--8", keywords = "Three-Dimensional Graphics and Realism,", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/grimm-2004-memory/", } @inproceedings{GRIMM-2004-FDMX-P, title = "Flexible Direct Multi-Volume Rendering in Interactive Scenes", author = "S\"{o}ren Grimm and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "In this paper we describe methods to efficiently visualize multiple ntersecting volumetric objects. We introduce the concept of V-Objects. V-Objects represent abstract properties of an object connected to a volumetric data source. We present a method to perform direct volume rendering of a scene comprised of an arbitrary number of possibly intersecting V-Objects. The idea of our approach is to distinguish between regions of intersection, which need costly multi-volume processing, and regions containing only one V-Object, which can be processed using a highly efficient brick-wise volume traversal scheme. Using this method, we achieve significant performance gains for multi-volume rendering. We show possible medical applications, such as surgical planning, diagnosis, and education.", month = oct, location = "Stanford, USA", booktitle = "Vision, Modeling, and Visualization (VMV)", pages = "386--379", keywords = "multi volume rendering, medical visualization, volume raycasting", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/GRIMM-2004-FDMX-P/", } @article{grimm-2004-arefined, title = "A Refined Data Addressing and Processing Scheme to Accelerate Volume Raycasting", author = "S\"{o}ren Grimm and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "Most volume rendering systems based on CPU volume raycasting still suffer from inefficient CPU utilization and high memory usage. To target these issues we present a new technique for efficient data addressing. Furthermore, we introduce a new processing scheme for volume raycasting which exploits thread-level parallelism—a technology now supported by commodity computer architectures.", month = oct, issn = "0097-8493", journal = "Computers & Graphics", number = "5", volume = "28", booktitle = "Computer & Graphics, Vol. 28 (5)", isbn = "0097-8493", pages = "719--729", keywords = "Volume Raycasting, Bricking, Parallel Co", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/grimm-2004-arefined/", } @inproceedings{Viola-2004-ImpX2, title = "Importance-Driven Volume Rendering", author = "Ivan Viola and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "This paper introduces importance-driven volume rendering as a novel technique for automatic focus and context display of volumetric data. Our technique is a generalization of cut-away views, which – depending on the viewpoint – remove or suppress less important parts of a scene to reveal more important underlying information. We automatize and apply this idea to volumetric data. Each part of the volumetric data is assigned an object importance which encodes visibility priority. This property determines which structures should be readily discernible and which structures are less important. In those image regions, where an object occludes more important structures it is displayed more sparsely than in those areas where no occlusion occurs. Thus the objects of interest are clearly visible. For each object several representations, i.e., levels of sparseness, are specified. The display of an individual object may incorporate different levels of sparseness. The goal is to emphasize important structures and to maximize the information content in the final image. This paper also discusses several possible schemes for level of sparseness specification and different ways how object importance can be composited to determine the final appearance of a particular object.", month = oct, isbn = "0780387880", publisher = "H. Rushmeier, G. Turk, J. van Wijk", booktitle = "Proceedings of IEEE Visualization 2004", pages = "139--145", keywords = "view-dependent visualization, non-photorealistic techniques, level-of-detail techniques, focus+context techniques, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Viola-2004-ImpX2/", } @article{grimm-2004-volume, title = "VOTS: VOlume doTS as a Point-Based Representation of Volumetric Data", author = "S\"{o}ren Grimm and Stefan Bruckner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "We present Volume dots (Vots), a new primitive for volumetric data modelling, processing, and rendering. Vots are a point-based representation of volumetric data. An individual Vot is specified by the coefficients of a Taylor series expansion, i.e. the function value and higher order derivatives at a specific point. A Vot does not only represent a single sample point, it represents the underlying function within a region. With the Vots representation we have a more intuitive and high-level description of the volume data. This allows direct analytical examination and manipulation of volumetric datasets. Vots enable the representation of the underlying scalar function with specified precision. User-centric importance sampling is also possible, i.e., unimportant volume parts are still present but represented with just very few Vots. As proof of concept, we show Maximum Intensity Projection based on Vots.", month = sep, journal = "Computer Graphics Forum", volume = "23", number = "3", issn = "0167-7055", pages = "668--661", keywords = "Graphics Data Structures and Data Types", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/grimm-2004-volume/", } @techreport{GRIMM-2004-PPC, title = "Parallel Peeling of Curvilinear Grids", author = "S\"{o}ren Grimm and Michael Meissner and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "In this paper we present a novel hybrid CPU-GPU approach for rendering curvilinear grids. Visibility sorting is accomplished by parallel peeling cells off the grid, utilizing an active cell peeling front. In each step, we compute the ray-cell intersection coordinates on the GPU, perform accurate volume integration (CPU), and determine the set of active cells for the next iteration (GPU). The approach requires only standard graphics capabilities and can therefore be used on any commodity PC, including laptops. Furthermore, the main memory requirements are negligible since the required data structures are minimal. The main advantage of our algorithm is that we exploit hardware acceleration for the expensive visibility sorting which is bene- ficial over time due to the faster performance increase of GPUs over CPUs. Due to the simplicity of the algorithm and its low requirements on preprocessing and main memory, it is well suited for thin clients. Last but not least, the approach could easily be extended to irregular grids using tetrahedra.", month = apr, number = "TR-186-2-04-07", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "Raycasting, Volume Rendering, Visibility Sorting, Curvilinear grids, Depth Sorting", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/GRIMM-2004-PPC/", } @inproceedings{Viola-2004-GPU, title = "GPU-based Frequency Domain Volume Rendering", author = "Ivan Viola and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "Frequency domain volume rendering (FVR) is a volume rendering technique with lower computational complexity as compared to other techniques. In this paper the FVR algorithm is accelerated by factor of 17 by mapping the rendering stage to the GPU. The overall hardware-accelerated pipeline is discussed and the changes according to previous work are pointed out. The three-dimensional transformation into frequency domain is done in a pre-processing step. The rendering step is computed completely on the GPU. First the projection slice is extracted. Four different interpolation schemes are used for resampling the slice from the data represented by a 3D texture. The extracted slice is transformed back into the spatial domain using the inverse Fast Fourier or Fast Hartley Transform. The rendering stage is implemented through shader programs running on programmable graphics hardware achieving highly interactive framerates.", month = apr, isbn = "80-223-1730-6", note = "second-best paper award!", booktitle = "Proceedings of SCCG 2004", pages = "49--58", keywords = "Fourier Transform, Fourier Volume Rendering, Hardware Acceleration", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Viola-2004-GPU/", } @article{knapp-2004-semi, title = "Semi-Automatic Topology Independent Contour-Based 2 1/2 D Segmentation Using Live-Wire", author = "Michael Knapp and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2004", abstract = "In general three-dimensional segmentation algorithms assume objects to have connected homogeneous regions. However in some cases objects are defined by a fuzzy boundary surface and consist of an inhomogeneous internal structure. In the following a new three-dimensional segmentation technique exploiting the contour detection capabilities of live-wire is proposed. The algorithm consists of two basic steps. First contours are outlined by the user on a small number of planar cross-sections through the object using live-wire. Second the traced contours are used for reconstructing the object surface automatically in each slice using live-wire again. This user-friendly segmentation algorithm is independent from object topology as the topology is implicitly defined during the reconstruction process.", month = feb, journal = "Journal of WSCG", volume = "12", number = "2", issn = "1213-6972", booktitle = "Journal of WSCG, Vol. 12, Number 2", isbn = "1213-6972", pages = "229--236", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/knapp-2004-semi/", } @techreport{Kanitsar-2004-Dia, title = "Diagnostic Relevant Visualization of Vascular Structures", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2004", abstract = "Traditional volume visualization techniques sometimes provide incomplete clinical information needed for applications in medical visualization. In the area of vascular visualization important features such as the lumen of a diseased vessel segment may not be visible. One way to display vascular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. Curved planar reformation (CPR) has proven to be an acceptable practical solution. We discuss four different methods to generate CPR images from single vessel segments: Projected CPR, stretched CPR, straightened CPR, and helical CPR. Furthermore we investigate three different methods for displaying vascular trees: Multi-path projected CPR, multi-path stretched CPR, and untangled CPR. The principle concept of each method is discussed and detailed information for the realization is given. In addition the properties, advantages and disadvantages of each method are summarized.", month = jan, number = "TR-186-2-04-02", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, computed tomography angiography, vessel analysis", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Kanitsar-2004-Dia/", } @phdthesis{Kanitsar-thesis, title = "Curved Planar Reformation for Vessel Visualization", author = "Armin Kanitsar", year = "2004", 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/2004/Kanitsar-thesis/", } @inproceedings{Viola-2003-Har, title = "Hardware-Based Nonlinear Filtering and Segmentation using High-Level Shading Languages.", author = "Ivan Viola and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2003", abstract = "Non-linear filtering is an important task for volume analysis. This paper presents hardware-based implementations of various nonlinear filters for volume smoothing with edge preservation. The Cg high-level shading language is used in combination with latest PC consumer graphics hardware. Filtering is divided into pervertex and per-fragment stages. In both stages we propose techniques to increase the filtering performance. The vertex program pre-computes texture coordinates in order to address all contributing input samples of the operator mask. Thus additional computations are avoided in the fragment program. The presented fragment programs preserve cache coherence, exploit 4D vector arithmetic, and internal fixed point arithmetic to increase performance. We show the applicability of non-linear filters as part of a GPU-based segmentation pipeline. The resulting binary mask is compressed and decompressed in the graphics memory on-the-fly.", month = oct, isbn = "0780381203", publisher = "IEEE", editor = "G. Turk, J. van Wijk, K. Moorhead", booktitle = "Proceedings of IEEE Visualization 2003", pages = "309--316", keywords = "Hardware Acceleration, Segmentation, Non-linear Filtering", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Viola-2003-Har/", } @techreport{Kanitsar-2003-ADV, title = "Advanced Curved Planar Reformation: Flattening of Vascular Structures", author = "Armin Kanitsar and Rainer Wegenkittl and Dominik Fleischmann and Eduard Gr\"{o}ller", year = "2003", abstract = "Traditional volume visualization techniques may provide incomplete clinical information needed for many applications in medical visualization. Especially in the area of vascular visualization important features such as the patent lumen of a diseased vessel segment may not be visible. Curved Planar Reformation (CPR) has proven to be an acceptable practical solution. Existing CPR techniques, however, still have diagnostically relevant limitations. In this paper we introduce two advanced methods for efficient vessel visualization, based on the concept of CPR. Both methods benefit from relaxation of spatial coherence in favor of improved feature perception. We present a new technique to visualize the interior of a vessel in a single image. A vessel is re-sampled along a spiral around the vessel central axis. The helical spiral depicts the vessel volume. Furthermore, a method to display an entire vascular tree without mutually occluding vessels is presented. Minimal rotations around the branching points of a vessel tree eliminate occlusions. For each viewing direction the entire vessel structure is visible.", month = may, number = "TR-186-2-03-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, vessel analysis, computed tomography angiography", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-ADV/", } @techreport{Knapp-2003-SAT, title = "Semi-Automatic Topology Independent Contour-Based 2 1/2 D Segmentation Using Live-Wire", author = "Michael Knapp and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2003", abstract = "In general three-dimensional segmentation algorithms assume objects to have connected homogeneous regions. However in some cases objects are defined by a fuzzy boundary surface and consist of an inhomogeneous internal structure. In the following a new three-dimensional segmentation technique exploiting the contour detection capabilities of live-wire is proposed: The algorithm consists of two basic steps. First contours are outlined by the user on a small number of planar cross-sections through the object using live-wire. Second the traced contours are used for reconstructing the object surface automatically in each slice using live-wire again. This user-friendly segmentation algorithm is independent from object topology as the topology is implicitly defined during the reconstruction process.", month = mar, number = "TR-186-2-03-06", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "connectivity graph, image processing, live-wire, segmentation", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Knapp-2003-SAT/", } @inproceedings{Kanitsar-2003-CTa, title = "CT angiography: Multi-path curved planar reformation of the peripheral arterial tree", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2003", publisher = "ECR", booktitle = "European Congress of Radiology", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-CTa/", } @inproceedings{Koechl-2003-Com, title = "Comprehensive assessment of peripheral arteries using multi-path curved planar reformation of CTA datasets", author = "Arnold K\"{o}chl and Armin Kanitsar and F. Lomoschitz and Eduard Gr\"{o}ller and Dominik Fleischmann", year = "2003", publisher = "ECR", booktitle = "European Congress of Radiology", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Koechl-2003-Com/", } @inproceedings{Kanitsar-2003-Adva, title = "Advanced Curved Planar Reformation: Flattering of Vascular Structures", author = "Armin Kanitsar and Rainer Wegenkittl and Dominik Fleischmann and Eduard Gr\"{o}ller", year = "2003", isbn = "0780381203", publisher = "IEEE", editor = "G. Turk, J. van Wijk, K. Moorhead", booktitle = "Proceedings of IEEE Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-Adva/", } @inproceedings{Kanitsar-2003-Dem, title = "Demonstration of different segmentation and visualization techniques by means of a complex real world object exemplified by a Christmas tree", author = "Armin Kanitsar and Dominik Fleischmann and Thomas Theu{\ss}l and Lukas Mroz and Milo\v{s} \v{S}r\'{a}mek and Eduard Gr\"{o}ller", year = "2003", publisher = "ECR", booktitle = "European Congress of Radiology", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-Dem/", } @techreport{Csebfalvi-2002-SBICG, title = "Smooth Shape-Based Interpolation using the Conjugate Gradient Method", author = "Bal\'{a}zs Cs\'{e}bfalvi and L\'{a}szl\'{o} Neumann and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2002", abstract = "In this paper a novel technique for smooth shape-based interpolation of volume data is introduced. Previously simple linear interpolation of signed distance maps has been used in practice. As it will be shown, this approach results in artifacts, since sharp edges appear along the original slices. In order to obtain a smooth 3D implicit function generated by interpolating 2D distance maps, we use a global interpolation method instead of a higher order local technique. The global curvature of the implicit function representing an isosurface is minimized using an iterative conjugate gradient method. Because of the iterative approach the user can easily control the trade-off between the smoothness of the isosurface and the computational cost of the refinement. As opposed to previous techniques, like variational interpolation, our method can generate a reasonably good approximation of the ideal solution in a significantly shorter time.", month = aug, number = "TR-186-2-02-10", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "shape-based interpolation, conjugate gradient method, volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Csebfalvi-2002-SBICG/", } @techreport{Wallisch-2002-INF, title = "Information Highlighting by Color Dependent Depth Perception with Chromo-Stereoscopy", author = "Bernd Wallisch and Wolfgang Meyer and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2002", abstract = "Due to characteristics of the human visual system different colors induce different depth perception. This chromo-stereoscopy has been already used for 3D data to enhance a third spatial dimension. We propose to use chromo-stereoscopy for 2D abstract data. Color coding introduces a depth cue which encodes relevance with chromo-stereoscopy. The focus information literally stands out as compared to the context information. We applied this technique on two-dimensional graphs and multi-layer representations. Our approach can also be easily combined with other focus+context methods.", month = jul, number = "TR-186-2-02-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "animation, multi-layer, graphs, focus+context, chromo-stereoscopy", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Wallisch-2002-INF/", } @techreport{kanitsar-2002-Chr, title = "Christmas Tree Case Study: Computed Tomography as a Tool for Mastering Complex Real World Objects with Applications in Computer Graphics", author = "Armin Kanitsar and Thomas Theu{\ss}l and Lukas Mroz and Milo\v{s} \v{S}r\'{a}mek and Anna Vilanova i Bartroli and Bal\'{a}zs Cs\'{e}bfalvi and Ji\v{r}\'{i} Hlad\r{u}vka and Stefan Guthe and Michael Knapp and Rainer Wegenkittl and Petr Felkel and Dominik Fleischmann and Werner Purgathofer and Eduard Gr\"{o}ller", year = "2002", abstract = "We report on using computed tomography (CT) as a model acquisition tool for complex objects in computer graphics. Unlike other modeling and scanning techniques the complexity of the object is irrelevant in CT, which naturally enables to model objects with, for example, concavities, holes, twists or fine surface details. Once the data is scanned, one can apply post-processing techniques aimed at its further enhancement, modification or presentation. For demonstration purposes we chose to scan a Christmas tree which exhibits high complexity which is difficult or even impossible to handle with other techniques. However, care has to be taken to achieve good scanning results with CT. Further, we illustrate the post-processing by means of data segmentation and photorealistic as well as non-photorealistic surface and volume rendering techniques.", month = mar, number = "TR-186-2-02-07", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "volume visualization, computed tomography, modeling", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/kanitsar-2002-Chr/", } @techreport{kanitsar-2002-CPRX, title = "CPR - Curved Planar Reformation", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2002", abstract = "Visualization of tubular structures such as blood vessels is an important topic in medical imaging. One way to display tubular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. This process is called Curved Planar Reformation (CPR). We present three different methods to generate CPR images. A tube-phantom was scanned with Computed Tomography (CT) to illustrate the properties of the different CPR methods. Furthermore we introduce enhancements to these methods: thick-CPR, rotating-CPR and multi-path-CPR.", month = mar, number = "TR-186-2-02-06", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, vessel analysis, computed tomography angiography", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/kanitsar-2002-CPRX/", } @inproceedings{Kanitsar-2002-Chri, title = "Christmas Tree Case Study: Computed Tomography as a Tool for Mastering Complex Real World Objects with Applications in Computer Graphics", author = "Armin Kanitsar", year = "2002", publisher = "IEEE Computer Society Press", booktitle = "Proceedings of IEEE Visualization", pages = "489--492", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Kanitsar-2002-Chri/", } @inproceedings{Csebfalvi-2002-Smo, title = "Smooth Shape-Based Interpolation using the Conjugate Gradient Method", author = "Bal\'{a}zs Cs\'{e}bfalvi and L\'{a}szl\'{o} Neumann and Armin Kanitsar and Eduard Gr\"{o}ller", year = "2002", publisher = "Akademische Verlagsgesellschaft Aka GmbH, Berlin", booktitle = "Vision, Modeling, and Visualization 2002", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Csebfalvi-2002-Smo/", } @inproceedings{Kanitsar-2002-CPR, title = "CPR- Curved Planar Reformation", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2002", publisher = "IEEE Computer Society Press", booktitle = "IEEE Visualization 2002", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Kanitsar-2002-CPR/", } @techreport{Kanitsar-2001-PVI, title = "Peripheral Vessel Investigation For Routine Clinical Use", author = "Armin Kanitsar and Rainer Wegenkittl and Petr Felkel and Dominik Fleischmann and Dominique Sandner and Eduard Gr\"{o}ller", year = "2001", abstract = "This paper is about computed tomography angiography based vessel exploration. Large image sequences of the lower extremities are investigated in a clinical environment. Two different approaches for peripheral vessel diagnosis dealing with stenosis and calcification detection are introduced. The paper presents an automated vessel-tracking tool for curved planar reformation. A user interactive segmentation tool for bone removal is proposed.", month = mar, number = "TR-186-2-01-13", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "optimal path computation, semi automated segmentation, CTA", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-PVI/", } @misc{Kanitsar-2001-Pos, title = "Postprocessing and Visualization of Peripheral CTA Data in Clinical Environments", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "Central European Seminar on Computer Graphics (CESCG'2001), Budmerice, Slovakia, April 23-25, 2001", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Pos/", } @misc{Kanitsar-2001-Per, title = "Peripheral Vessel Investigation for Routine Clinical Use", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "Proceedings of IEEE Visualization 2001, October 2001, San Diego, USA, pp. 91-98
 ", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Per/", } @misc{Kanitsar-2001-Aut, title = "Automated Vessel Detection at Lower Extremity Multislice CTA", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "European Congress of Radiology 2001 (ECR 2001), March 2-6 2001, Vienna", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Aut/", } @xmascard{xmas-2001, title = "X-Mas 2001", author = "Armin Kanitsar", year = "2001", abstract = "This picture shows a volume rendering visualization of a CT-Scan of a real world christmas tree. Created by the Vis-Group in cooperation with the general hospital vienna.", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/xmas-2001/", }