High density image-storage holograms by a random phase sampling method.

The random phase sampling method that has been proposed to make high quality and high storage density holograms capable of storing image information is described and discussed from the aspect of the quantitative characteristics of its reconstructed image. The method enables the uniform distribution of light energy over the hologram area made on the exact Fourier transformed plane. The details of the characteristics of the method are investigated, especially with respect to the luminance tone linearity, the signal-to-noise ratio, and the resolution to give good agreement with the results of a calculation. In the experiment, reconstructed images with high quality were obtained from holograms of 2-mm diam, which were made by 10(6) sampling and random phase shifting. By using the random phase sampling medthod, an image retrievel model system storing twenty kinds information was developed. This system holds promise of being used in various practical applications such as holographic ultramicrofilm system or a holographic videopackage system.