New searching flow scheme for incremental backprojection algorithm

A new two-dimensional (2D) searching flow scheme is proposed for the incremental backprojection algorithm (see IEEE Trans. Med. Imaging, vol.9, p.207, 1990). In this scheme, the searching direction in a beam is determined only by the distance of the current pixel to the corresponding ray and no pixels outside the beam are involved in the procedure. The proposed scheme possesses a simple structure. Implementations on an AST-386 computer for the incremental backprojection algorithm by using this new scheme show that the processing time can be reduced by a factor of approximately 1.4 compared with the original scheme.