Signal-to-noise ratios for hologram images of subjects in strong incoherent light.

When normal laser holographic technique is applied to subjects in strong incoherent illumination, an additional darkening of the photographic plate due to the incoherent light is introduced. Effects of the darkening on the signal-to-noise ratio of the reconstructed image are analyzed using a simplified model for photographic plate characteristics. Optimum values of the fraction of laser light used as reference, plate exposure, and S/N are obtained. Reconstructed images of reasonable contrast and pictorial quality have been obtained for 3-D subjects illuminated with substantial incoherent light intensity in addition to the laser light.