A technique to determine a real nonnegative function representing the transmittance of a synthesized hologram is described. The technique uses the positions of the samples in the synthesized hologram to record the phase information of a complex wavefront. Synthesized holograms are displayed on a flying spot scanner and recorded on film. The transmittance of the synthesized hologram is quantized into 256 levels because of a hardware limitation of the scanner.
Wai Hon Lee, "Sampled Fourier Transform Hologram Generated by Computer," Appl. Opt. 9, 639-643 (1970)