Wave atoms for digital hologram compression

Compression of macroscopic digital holograms is a major research problem, which if unresolved would continue limiting the possible applications of holography in multimedia contexts. The quest of searching for the most suitable representation for compression is still an open problem. In this work, we study sparsification by the wave atom transform, introduced in 2006 by Demanet et al., and experiment on four large-scale representative diffuse macroscopic holograms while testing compressibility in the object-plane, Fourier-plane, and defocused plane representations, respectively. We demonstrate that it is a suitable non-adaptive, sparsifying transform for Fourier or defocused content and by integration into the Wave Atom Coding (WAC) method, we sketch a full fledged codec for the compression of macroscopic holograms. WAC is compared to two variants of JPEG 2000, with equal complexity of coding tools, and the more recent H.265/HEVC. For Fourier and defcoused holograms WAC outperforms the JPEG 2000 variants by 0.9 − 7.9 dB BD-PSNR, especially in the former case, while it is as good as or better than even H.265/HEVC for very deep computer-generated holograms, thus improving on existing approaches. © 2019 Optical Society of America