Color-reflection holography: theory and experiment

We present a theoretical and experimental analysis of color-reflection holography. Full parallax three-dimensional color images are obtained by the superposition of wavelength-selective reflection holograms recorded at eight combinations of three laser wavelengths. The test object used was a set of eight Munsell color chips recommended by the Commission Internationale de l'Eclairage (CIE) for color-rendering analysis. The spectral power distributions of all the holographic images are measured using a telespectroradiometer and corresponding points are calculated and plotted on a color diagram. The holograms are modeled by a combination of sinc functions for the diffracted replay signal and an empirically determined function for the replay scatter noise. A new definition of signal-to-noise ratio for color holograms is described. The model is matched to a spectral power distribution by choosing values for relative diffraction efficiencies, bandwidth, signal-to-noise ratio, and wavelength shift components. One spectral power distribution having been matched, theoretical predictions of the remaining colors in the holographic images are obtained. The predictions mapped on the CIE 1976 diagram are shown to agree with experimental results: the average distance between theoretical and experimental points on the CIE diagram for all eight Munsell chips on all eight holograms is 0.0001 CIE 1976 chromaticity diagram unit; the discrepancy of the average gamut area between theoretical and experimental points on the CIE diagrams was < 10%. Good agreement between theory and experiment having been shown, a synthesis of holographic color reproduction at any combination of wavelengths predicts optimum recording wavelengths of 460, 530, and 615 nm for typical replay by a color-reflection hologram.