METHOD AND APPARATUS FOR VISUALIZATION OF 3D VOXEL DATA USING LIT OPACITY VOLUMES WITH SHADING

A volume rendering process is disclosed for improving the visual quality of images produced by rendering and displaying volumetric data in voxel format for the display of three-dimensional data on a two-dimensional display, with opacity (1402) and shading (1404) to control the realistic display of images rendered from the voxels. The process includes partitioning the plurality of voxels among a plurality of slices with each slice corresponding to a respective region of the volume. Each voxel includes an opacity value adjust ed by applying an opacity curve to the value. The opacity value of each voxel i n each cell in the volume is converted into a new visual opacity value that is used to calculate a new visual opacity gradient (1403) for only one voxel in the center of each cell. The visual opacity gradient is used to calculate th e shading used to modify the color of the individual voxels based on the orientation of opacity isosurfaces passing through each voxel in the volume in order to create a high quality realistic image.