A parallel implementation of 3-D CT image reconstruction on hypercube multiprocessor

A parallel is given of how image reconstruction in computerized tomography (CT) can be parallelized on a message-passing multiprocessor. In particular, the results obtained from parallel implementation of 3-D CT image reconstruction for parallel beam geometries on the Intel hypercube, iPSC/2, are presented. A two-stage pipelining approach is used for filtering (convolution) and backprojection. The conventional sequential convolution algorithm is modified such that the symmetry of the filter kernel is fully utilized for parallelization. In the backprojection stage, the 3-D incremental algorithm, a recently developed backprojection scheme which is shown to be faster than the conventional algorithm, is parallelized. The speed-up, defined as sequential processing time/parallel processing time, ranging from 5 to 27, and the efficiency, defined as speed-up/the number of processing elements, ranging from 60% to 92%, have been achieved, depending on the size of the image and the number of processing elements used