Graphics Hardware (2004) T. Akenine-Möller, M. McCool (Editors) Hardware-based Simulation and Collision Detection for Large Particle Systems

Particle systems have long been recognized as an essential building block for detail-rich and lively visual environments. Current implementations can handle up to 10,000 particles in real-time simulations and are mostly limited by the transfer of particle data from the main processor to the graphics hardware (GPU) for rendering. This paper introduces a full GPU implementation using fragment shaders of both the simulation and rendering of a dynamically-growing particle system. Such an implementation can render up to 1 million particles in real-time on recent hardware. The massively parallel simulation handles collision detection and reaction of particles with objects for arbitrary shape. The collision detection is based on depth maps that represent the outer shape of an object. The depth maps store distance values and normal vectors for collision reaction. Using a special texturebased indexing technique to represent normal vectors, standard 8-bit textures can be used to describe the complete depth map data. Alternately, several depth maps can be stored in one floating point texture. In addition, a GPU-based parallel sorting algorithm is introduced that can be used to perform a depth sorting of the particles for correct alpha blending

Non-linear Registration of Pre- and Intraoperative Volume Data Based On Piecewise Linear Transformations

For the planning of minimal invasive brain surgery detailed knowledge of the individual anatomical structures is necessary. Therefore in medical practice high--resolution MR image data is recorded preoperatively. Due to tissue resection and cerebrospinal fluid leakage both shape and position of the brain change during the intervention (brain--shift). Therefore intraoperative data is used in addition, providing exact anatomical information. In order to accommodate the deformations of tissue for computer assisted surgery, nonlinear registration of the voxel data must be performed. In this context we propose a new voxel--based approach based on maximization of mutual information. For fast evaluation the nonlinear deformation is modeled by adaptively subdividing the data set into piecewise linear patches. The parameters of this multidimensional transformation are optimized using Powell's direction set method. Since 3D-- texture hardware is exploited to evaluate trilinear interpolations, th..

Abstract Interactive Volume Rendering on Standard PC Graphics Hardware Using Multi-Textures and Multi-Stage Rasterization

Interactive direct volume rendering has yet been restricted to high-end graphics workstations and special-purpose hardware, due to the large amount of trilinear interpolations, that are necessary to obtain high image quality. Implementations that use the 2D-texture capabilities of standard PC hardware, usually render object-aligned slices in order to substitute trilinear by bilinear interpolation. However the resulting images often contain visual artifacts caused by the lack of spatial interpolation. In this paper we propose new rendering techniques that significantly improve both performance and image quality of the 2D-texture based approach. We will show how multi-texturing capabilities of modern consumer PC graphics boards are exploited to enable interactive high quality volume visualization on low-cost hardware. Furthermore we demonstrate how multi-stage rasterization hardware can be used to efficiently render shaded isosurfaces and to compute diffuse illumination for semi-transparent volume rendering at interactive frame rates

Interactive Volume Rendering on Standard PC Graphics Hardware Using Multi-Textures and Multi-Stage Rasterization

Interactive direct volume rendering has yet been restricted to high-end graphics workstations and special-purpose hardware, due to the large amount of trilinear interpolations, that are necessary to obtain high image quality. Implementations that use the 2D-texture capabilities of standard PC hardware, usually render object-aligned slices in order to substitute trilinear by bilinear interpolation. However the resulting images often contain visual artifacts caused by the lack of spatial interpolation. In this paper we propose new rendering techniques that signi cantly improve both performance and image quality of the 2D-texture based approach. We will show how multi-texturing capabilities of modern consumer PC graphics boards are exploited to enable interactive high quality volume visualization on low-cost hardware. Furthermore we demonstrate how multi-stage rasterization hardware can be used to eciently render shaded isosurfaces and to compute di use illumination for semi-transparent v..

An interactive, multi-modal approach to analysing high-resolution image mass spectrometry data

The output resolution of imaging mass spectrometers is increasing rapidly due to advances in engineering and the use of tiling. Imaging-MS data is often displayed as a total-ion-count (TIC) image; however, anatomical structures are not easily identifiable from TIC images. For this purpose, additional high-resolution images that originate from different imaging modalities, such as stained histological data, are preferred. These modalities are most useful when fused; i.e., when the corresponding images are spatially aligned with respect to each other. The viewing and analysis of such data is ideally performed in real-time and at the highest possible resolution, allowing users to interactively query the combination of all fused data at the highest detail. However, proper alignment between modalities and interactively presenting large volumes of data is as of yet a challenge. We present a system for the simultaneous viewing and analysis of high-resolution data from different imaging modalities. Fusion is provided in such a way that interaction in one modality can be mapped to different modalities. For example, anatomical structures can be identified from histological data and their spatial extent mapped to a corresponding region-of-interest in the image MS data, allowing the analysis of its chemical compounds. In turn, the MS data can be analysed and filtered, for example using multi-variate analysis such as PCA, and the result mapped back to structures in other modalities. Level-of-detail, region-of-interest and asynchronous data processing algorithms ensure that the system can be operated interactively at the highest resolution

TOMANDL B.: Automated 3d video documentation for the analysis of medical data

Abstract. The usual way todocument medical data is using 2D images and textual transcription as medium. But for analysing the position and the spatial dimensions of an aneurysma 3D information is mandatory. This information can be provided by digital videos that show the visualized 3D medical data set. However, to generate such videos usually is avery inconvenient and time-consuming procedure. To automate this it is necessary to de ne a standardized way of observing the medical data set. The following paper presents an approach to automatically record a digital video sequence of an aneurysma in CT-data sets which is based on hardware supported texture mapping.