Non-photorealistic volume visualization with color distance gradient and two-level volume rendering

Traditional approaches for rendering photographic volumetric data sets usually use the original color from data set. But for some complicated medical object, it delivers unsatisfactory results. In this paper, we proposed a novel non-photorealistic volume rendering (NPVR) technique, color distance gradient for opacity design and two-level volume rendering, based on graphics processing unit (GPU) accelerated raycasting, to address this problem. Segmentation information is adopted to enhance the performance of visualization and special structure can be highlighted in the volume according to user´s feedback. Visible Human Project (VHP) data set is used for test and the result confirms that our method is effective.