Birnbaum, T. (2022). A generic source coding methodology and architecture of dynamic holograms. [PhD Thesis, Vrije Universiteit Brussel].

@phdthesis{468833e1dce7453491f7a205058262ae,
title = "A generic source coding methodology and architecture of dynamic holograms",
abstract = "For wave phenomena, the holographic principle describes how, based upon lightpropagation laws and a recording of the amplitude and the phase of a wavefront in one place – called a hologram – a wave front in another place can beobtained. The holographic principle can be applied to, among others anyelectro-magnetic wave. It has great impact on applications such as holographicmicroscopy, interferometry and non-destructive testing.Applied to visible light, holograms allow seamless observation of 3D contentwithout any distortions or adversary effects such as mismatching visual cues. Atsufficient space-frequency bandwidths, holograms become opticallyindistinguishable from reality and can be refocused at observation time. Whenthose high-quality holograms became digitally accessible due to advances inprocessing power in recent years, manipulation, duplication, and computergeneration from purely synthetic content became feasible. Applied tomacroscopic content, the mostpromising applications include preservation of cultural treasures, art,entertainment, educational purposes, medical imaging, surgical assistance, bigdata visualizations, and computer aided design.However, digital holograms can only convey as much information because oftheir large space-frequency bandwidths resulting in resolutions of severalgigapixel. Thus compression becomes a necessity, especially for dynamiccontent. As holograms of visible light are based on the interference of diffractedcoherent light, they look similar to the patterns visible on the surface of a pond,after throwing a hand full of pebbles into. In a numerical hologram, typically,each point in the scene influences every point in the hologram. Both factstogether render signal characteristics of holograms conceptually very different from regular images and videos, and thus novel strategies to compress dynamic holograms need to be investigated.This PhD thesis consists of several aspects necessary to design such strategiesas well as a first proposition of a holographic video codec suitable for multiple independently objects. Most contributions exploit heavily the concepts of spatialfrequency (number of lines per unit length) and optical phase-space (alsoknown as space-frequency or time-frequency domain). The novel contributionsinclude: compression of static Fourier holograms based on wave atomsrefinement of a STFT based static compresion scheme suited for all DH types asegmentation of holograms corresponding to scenes of multiple independently moving objects and resulting from it, a generic holographic motion compensation scheme for such scenes. From the latter an inter-frame compression strategy is derived and a generic video compression scheme is proposed. Further contributions concern, various contributions to subjective quality assessment of digital holograms a newly proposed versatile similarity measure for complex numbers and studies on speckle denoising of the back-propagated wave fields with the objective to find low complexity algorithms with acceptable visual performance.",
author = "Tobias Birnbaum",
year = "2022",
language = "English",
school = "Vrije Universiteit Brussel",
}