Coherence aware GPU-based ray casting for virtual colonoscopy

TL;DR: A GPU-based volume ray casting for virtual colonoscopy to generate high-quality rendering images with a large screen size by using a triangle mesh of first-hit points and checking the intersection of each triangle with the corresponding real surface.

Abstract: In this paper, we propose a GPU-based volume ray casting for virtual colonoscopy to generate high-quality rendering images with a large screen size. Using the temporal coherence for ray casting, the empty space leaping can be efficiently done by reprojecting first-hit points of the previous frame; however, these approaches could produce artifacts such as holes or illegal starting positions due to the insufficient resolution of first-hit points. To eliminate these artifacts, we use a triangle mesh of first-hit points and check the intersection of each triangle with the corresponding real surface. Illegal starting positions can be avoided by replacing a false triangle cutting the real surface with five newly generated triangles. The proposed algorithm is best fit to the recent GPU architecture with Shader Model 4.0 which supports not only fast rasterization of a triangle mesh but also many flexible vertex operations. Experimental results on ATI 2900 with DirectX10 show perspective volume renderings of over 24fps on 1024 × 1024 screen size without any loss of image quality. Copyright © 2008 John Wiley & Sons, Ltd.