@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/", } @phdthesis{phd-viola, title = "Importance-Driven Expressive Visualization", author = "Ivan Viola", year = "2005", abstract = "In this thesis 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 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. 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.", month = jun, 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/2005/phd-viola/", } @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/", } @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/", } @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/", } @mastersthesis{knapp_michael_2004_MAS, title = "Memory Allocation Strategies for Large Volumetric Data-Sets", author = "Michael Knapp", year = "2004", abstract = "Since the development of medical three dimensional imaging devices in the 1970s, volumetric data processing has tremendously gained in importance. With the growing size of the data-sets, exhausting the capabilities of the hardware of its time, methods for efficient volumetric data processing have been always a hot topic. In this diploma thesis two approaches for processing large volumetric data-sets are presented. Both approaches utilize a block volume for storing the data. Further data compression and out-of-core processing are incorporated. Efficiency is achieved by processing only the required portion of data while omitting the non-related data having no effect on the intended result of the algorithm. This is supported by utilization of the knowledge about access patterns of the algorithm. Also methods for optimizing the efficiency by exploiting architectural properties of the computer hardware are presented.", month = dec, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "volume processing, large data", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/knapp_michael_2004_MAS/", } @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/", } @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{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-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/", } @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/", } @mastersthesis{bruckner-2004-EVV, title = "Efficient Volume Visualization of Large Medical Datasets", author = "Stefan Bruckner", year = "2004", abstract = "The size of volumetric datasets used in medical environments is increasing at a rapid pace. Due to excessive pre-computation and memory demanding data structures, most current approaches for volume visualization do not meet the requirements of daily clinical routine. In this diploma thesis, an approach for interactive high-quality rendering of large medical data is presented. It is based on image-order raycasting with object-order data traversal, using an optimized cache coherent memory layout. New techniques and parallelization strategies for direct volume rendering of large data on commodity hardware are presented. By using new memory efficient acceleration data structures, high-quality direct volume rendering of several hundred megabyte sized datasets at sub-second frame rates on a commodity notebook is achieved.", month = may, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "volume rendering, large data", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/bruckner-2004-EVV/", } @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/", } @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/", } @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/", } @talk{viola-2004-idv, title = "Importance-Driven Volume Rendering", author = "Ivan Viola", year = "2004", event = "IDVR", location = "Austin, USA", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/viola-2004-idv/", } @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/", } @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/", } @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/", } @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/", } @inproceedings{Neumann-2002-Fea, title = "Feature-Preserving Volume Filtering", author = "L\'{a}szl\'{o} Neumann and Bal\'{a}zs Cs\'{e}bfalvi and Ivan Viola and Matej Mlejnek and Eduard Gr\"{o}ller", year = "2002", abstract = "In this paper a feature-preserving volume filtering method is presented. The basic idea is to minimize a three-component global error function penalizing the density and gradient errors and the curvature of the unknown filtered function. The optimization problem leads to a large linear equation system defined by a sparse coefficient matrix. We will show that such an equation system can be efficiently solved in frequency domain using fast Fourier transformation (FFT). For the sake of clarity, first we illustrate our method on a 2D example which is a dedithering problem. Afterwards the 3D extension is discussed in detail since we propose our method mainly for volume filtering. We will show that the 3D version can be efficiently used for elimination of the typical staircase artifacts of direct volume rendering without losing fine details. Unlike local filtering techniques, our novel approach ensures a global smoothing effect. Previous global 3D methods are restricted to binary volumes or segmented iso-surfaces and they are based on area minimization of one single reconstructed surface. In contrast, our method is a general volume-filtering technique, implicitly smoothing all the iso-surfaces at the same time. Although the strength of the presented algorithm is demonstrated on a specific 2D and a specific 3D application, it is considered as a general mathematical tool for processing images and volumes.", month = may, publisher = "ACM", booktitle = "Data Visualization 2002", pages = "105--114", keywords = "antialiasing, noise filtering, derivative and gradient estimation, feature-preserving smoothing, direct volume rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Neumann-2002-Fea/", } @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/", } @article{Hladuvka-2002-Exp, title = "Exploiting the Hessian matrix for content-based retrieval of volume-data features", author = "Ji\v{r}\'{i} Hlad\r{u}vka and Eduard Gr\"{o}ller", year = "2002", journal = "Visual Computer", number = "4", volume = "18", pages = "207--217", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Hladuvka-2002-Exp/", } @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/", }