Patent ID: 7133041

Claim:
A method for performing approximate perspective volumetric ray casting of a three-dimensional (3D) volume dataset, the volume dataset comprising a plurality of discrete voxels stored in a distributed fashion in a plurality of three-dimensional (3D) memory units, each of the voxels having a location lying on a gridpoint in the volume dataset and having voxel data associated therewith, the method comprising the steps of: (a) selecting viewing and processing parameters which define: a viewpoint; and a view direction; (b) calculating a length of the volume dataset between the location of the nearest voxel to the viewpoint and the farthest voxel from the viewpoint, the length being measured along one of: (i) a line parallel to the view direction; and (ii) an axis of the three-dimensional volume dataset that is most parallel to the view direction; (c) dividing the volume dataset along the measured length into a plurality of slabs, each of the plurality of slabs having an orientation that is perpendicular to the measured length and defines a plane having a position with respect to the viewpoint in three dimensional space; (d) generating a perspective projection; (e) rendering each of the plurality of slabs by parallel projection onto a plurality of separate baseplane images; (f) texturing each of the plurality of images through the perspective projection onto their respective plane; and (g) blending the plurality of textured images together to form the final image.