Citation Context

...lighting parameters, but rendered with different algorithms: a nonpolygonal ray-cast isosurface rendering and a shear-warp direct volume rendering produced with the Stanford VolPack rendering library =-=[10]-=-. Towards the bottom of the direct volume rendered image, there is some fogginess surrounding the surface, and the surface itself is not very clear. As can be confirmed by looking directly at slices o...

Citation Context

...o apply these ideas to texture-based rendering approaches. The basic idea of using object-aligned textured slices to substitute trilinear by bilinear interpolation was presented by Lacroute and Levoy =-=[6]-=-, although the original implementation did not use texturing hardware. For the PC platform, Brady et al. [2] have presented a technique for interactive volume navigation based on 2D texture mapping. T...

Citation Context

...lume rendering hardware. Optimized software techniques for volume rendering require pre-computation and additional data storage, and they often sacrifice image quality for speed. Shear-warp rendering =-=[11]-=- is currently the fastest software algorithm. It achieves 1.1 Hz on a single 150MHz R4400 processor for a 256 256 225 volume with 65 seconds of pre-processing time [10]. Unfortunately, pre-process...

Citation Context

... the Cube-4 architecture [27] and the subsequent VolumePro PCI graphics board [25]. The VolumePro graphics board implements ray casting combined with the shear warp factorization for volume rendering =-=[16]-=-. It features trilinear interpolation with supersampling, gradient estimation, shaded volumes, and provides interactive frame rates for scalar volumes with sizes up to . 4 Multi-Dimensional Transfer F...

Citation Context

...mated (such as gradient magnitude) that it makes perfect sense for them to be in the transfer function domain. Sometimes, for instance, the gradient magnitude is precomputed for reasons of efficiency =-=[24]-=-, but one can also imagine ray-tracing approaches that do sophisticated filtered derivative estimation and eigensystem computation at every sample in order to compute coordinates in a curvature based ...

Citation Context

...ay the v oxel data.We will focus on interactiv e direct methods. The basic idea of using object-aligned slices to substitute trilinear b y bilinear interpolation was presen ted b y Lacroute and Levoy =-=[7]-=-, although the original implementation did not use texturing hardware. For the PC platform, Brady et al. [1] ha ve presen ted a tec hnique for interactive volume navigation based on 2D-texture mapping...

Citation Context

...face scattering of light. In volume modeling, an object is represented as a 3D array of voxels [16]. To accelerate volume rendering and the traversal of a volume, octrees [18] and run-length encoding =-=[17]-=- have been used as means of efficiently storing voxel data, while shells have been used to encode the location of high-opacity voxels in the vicinity of the boundary [34]. This latter representation i...