The results of a comparative experimental study of hologram coding methods using hybrid (opto-digital) techniques are presented. A series of Fresnel CGH (computer generated holograms) transparencies of a simple test object are produced using different binary and non-binary encoding schemes and the corresponding optically reconstructed images are compared and used to present and support the findings and conclusions of the study. A new binary hologram encoding method derived from the Lissajous pattern representation of amplitude and phase is also discussed and demonstrated. The method appears to furnish images with better quality than other binary encoding techniques because of better utilization of the degrees of freedom available for coding holographic data in each pixel of a purely amplitude modulating transparencies.
N. H. Farhat,
T. H. Chu,
"Lissajous Coding For Computer Generated And Longwave Holography", Proc. SPIE 0437, Intl Conf on Computer-Generated Holography, (26 October 1983); doi: 10.1117/12.937126; https://doi.org/10.1117/12.937126