| 摘要 |
<p>In order to reduce the amount of re-calculations needed when mapping functions to a color/opacity volume are changed, the processing of a volume rendering method is separated into two portions, the first depending on the volume data (i.e., a portion determined by the volume data) and the second depending on the mapping to the color and opacity. Pre-processing calculations will then be limited to the portion depending on the volume data, so as to thereby allow mapping functions to the color and opacity to be changed interactively. To this end, a "VIS volume" that consists of a data value, a shaded intensity, and a surface strength, and is expressed by 3 bytes per one voxel, is calculated and ray-traced. The color and opacity at each sampling point are determined when the VIS volume is sampled. Therefore, even if the mapping functions to the color and opacity are changed, it is not necessary to calculate the VIS module again. <IMAGE></p> |
