High quality phase-only hologram generation for holographic display

Abstract

Holography is a promising display technology capable of realizing 3D images, but it is faced with difficulties due to several limitations. Among them, the excessive amount of computation required to convert a computer-generated complex hologram into a phase-only hologram makes it challenging to implement a real-time display. In this paper, methods to resolve the speed-quality tradeoff relationship in phase-only hologram generation is presented. A method to improve the quality of the double phase hologram in the noniterative method was presented. By introducing weights, the intensity of peripheral noise, which was unavoidable due to the double phase method's characteristics, was reduced, and the image expression range and diffraction efficiency were increased. In the iterative method, a method of improving the accuracy of initial phase by calculating each hologram after dividing the image and a method of recycling the phase of the previous frame in the video were presented. In addition, a method of improving the hologram quality by using the histogram-adjusted image as a constraint in the initial iteration was suggested. The proposed methods were verified through computer simulation and optical reconstruction. Since the proposed method does not conflict with the existing improvement algorithms, it was applied together to further improve performance. The result is meaningful in that it presents the possibility of improving performance through numerical optimization in the noniterative methods and the importance of the histogram of the target image in the iterative methods.