Computer Generated Holography as a Three-Dimensional Display Medium

A process was developed to produce three dimensional images using computer generated holography CGH. This process consisted of a series of steps that began with a geometric description of an object and concluded with a three dimensional holographic image being computed from a synthetic wavefront. The objects used in this series of steps or CGH pipeline were described geometrically as a collection of three dimensional points. The modular nature of the CGH pipeline provided a flexible platform from which to evaluate various object geometries, interference calculations algorithms, and interference pattern recording and reduction techniques. This system was implemented with general purpose computer workstations to compute the interference patterns, a postscript laser printer to record the patterns, and standard photographic reduction techniques to generate transmission holograms. Optical density filters were used to allow a holograms virtual image to be safely viewed through the transmission hologram down the bore of the laser. The holograms real image was observed as a collection of the objects planes captured on a white card. The reference beam was modeled as a plane wave normal to the recording surface with a constant phase angle of zero radians at all locations of the recording surface. The major constraint of this system was the limited spatial resolution of the laser printer which limited the geometric placement of the objects to be recorded.