Histogram compensation algorithm for an efficient phase-only hologram calculation

A fast computer-generated phase-only hologram (POH) calculation is needed to realize a holographic display. Existing iterative methods require many iterations and thus require speed improvement, and noniterative methods add constraints to the image, resulting in restrictions on quality or range of expression. In this paper, we propose an efficient iteration algorithm without using a feedback process. For the several initial iterations among the entire iteration process, the image constraint was replaced by a histogram adjusted image. This pre-iteration can compensate for the loss of bright and dark pixels in the image reconstructed by the POH, resulting in a more accurate POH. The quality of image reconstructed by the proposed method was compared with that of existing algorithms by computer simulation and optical regeneration. Compared to the previous method, a 1.17dB increase in peak signal-to-noise ratio was obtained, and the number of iterations to achieve the same image quality has been reduced by 23%. The proposed method hardly increased the amount of computation and could be used simultaneously with the existing feedback methods.