Apparatus and method for parallel and perspective real-time volume

Abstract

An apparatus and method for parallel and perspective real-time volume visualization. The method employs ray-slice-sweeping and includes the steps of selecting viewing and processing parameters; initializing a compositing buffer; sampling voxel values from a three dimensional memory buffer onto a current slice of sample points; combining the sample point values with pixels of the compositing buffer along a plurality of interstice ray segments which extend only between the current slice and an adjacent slice associated with the compositing buffer; and repeating the sampling and combining steps by subsequentially sweeping through subsequent slices of sample points parallel to the first processing slice until the last processing slice is reached. Each of the subsequent slices in turn becomes the current slice. The apparatus includes a three dimensional buffer; a pixel bus; a plurality of rendering pipelines; and a control unit. The plurality of rendering pipelines each include a first slice unit; a compositing unit; a two dimensional slice compositing buffer; and a first (preferably bilinear) interpolation unit. Sample point values are combined with pixels of the compositing buffer in the compositing unit along the plurality of interslice ray segments which extend only between a current slice contained in the slice unit and a slice contained in the two-dimensional slice compositing buffer. In the apparatus and method of the present invention, gradients are computed at voxel positions, improving accuracy and allowing for a more compact implementation with less control overhead than prior methods and apparatuses.