Parallel volume rendering system with a resampling module for parallel and perspective projections

Abstract

A volume rendering system re-samples voxels read from a voxel memory to generate samples along perspective rays cast from a center of projection using a level of detail value. Color computations are performed with the samples to produce pixels for a baseplane image. The level of detail is computed, at each plane of samples perpendicular to a principal viewing axis, from the current sample position and the distance between the center of projection and the baseplane; the principal viewing axis is the coordinate axis in a rendered volume most parallel with a viewing vector. The level of detail provides a measure of the distance between two neighboring perspective rays at each plane and is used to determine the number of voxels and weights for these voxels required to compute a single sample at each plane. Multi-resolution datasets prepared for different levels of details are used to simplify the resampling operation by limiting the number of voxels required to compute a single sample.