Lossless compression of CGH via resolution-controlled sub-hologram.

Holographic displays require submicron pixel pitches to achieve wide viewing angles, resulting in extremely large data sizes. Inspired by foveated rendering, we propose a method that selectively reduces the resolution of peripheral regions by controlling the resolving power between two point light sources based on the Rayleigh criterion. This approach allows resolution-controlled sub-holograms to be generated using a single-panel spatial light modulator without hardware modifications. The characteristics of hologram data generated by this method were analyzed, and five lossless compression algorithms were evaluated. As the resolution decreased, the dynamic range and high-frequency components of the interference pattern were reduced, leading to increased spatial correlation and improved compressibility. Consequently, compression rates of 40%-70% were achieved in the peripheral regions without noticeable degradation in the reconstructed images. The compression efficiency was found to be consistent regardless of the number of point light sources, viewing positions, or object shapes. These results demonstrate that incorporating foveated rendering principles into hologram generation provides an effective strategy for reducing data size while maintaining image quality in the foveal region.