Optical Hough-transform processor with a two-dimensional array of computer-generated holograms

An optical implementation of the Hough transform that uses a two-dimensional array of computergenerated holograms based on a direct-binary-search algorithm is investigated. A Hough-transform filter consisting of 16 × 16 Fourier-transform direct-binary-search computer-generated holograms is examined. A novel matrix format, which uses the parameter domain in the Hough transform instead of a conventional orthogonal coordinate system, enables highly flexible fabrication of a Hough-transform filter by reducing constraints for reconstructed sample points of a computer-generated hologram. A completed Hough-transform filter has excellent performance both in the quality of the reconstructed image and in diffraction efficiency.