High quality per-pixel shading in texture-based volume rendering

We present a novel technique for texture-based volume rendering that provides the image with high quality based on the per-pixel shading. Our method produces accurate shading for the arbitrary and dynamically changing directional light source. This is achieved by using the normalized gradient during the lighting and calculating the shading on each pixel. Additionally, we present a new technique circumventing the huge memory consumption of previous approaches by estimating the gradient on the fly. This algorithm is unique in that it utilizes sophisticated PC graphics hardware functionality, especially the fragment program, to enable fast data loading and interactive rendering. Several examples are given to illustrate its effectiveness on real clinic 3D CT datasets