A generic source coding methodology and architecture of dynamic holograms 

I am interested in developing and furthering a generic source coding methodology and architecture of dynamic holograms, or in other words a holographic video compression scheme.

A recording of amplitude and phase of a wave phenomenon on one surface is called a hologram. When the laws of wave propagation are known, a hologram allows for obtaining the amplitude and phase on a different surface, and therefore an accurate physical reproduction of the wave in a different place. This is described by the holographic principle or called shortly holography. The holographic principle can be applied to, among others, any electro-magnetic wave. Holography had already a great impact on applications such as holographic microscopy, interferometry, non-destructive testing. It is also projected to be the ultimate 3D visualization methodology.

"We are all equal before a wave. (Laird John Hamilton 1964-)"

Applied to visible light, holograms allow also for the seamless observation of 3D content without any distortions or adversary effects such as mismatching visual cues. At sufficient space-frequency bandwidths, holograms become optically indistinguishable from reality and can be refocused at observation instead of recording time. When those high-quality holograms became digitally accessible due to advances in processing power in recent years, manipulation, duplication, and computer-generation from purely synthetic content became feasible. Applied to macroscopic content, the most promising applications include preservation of cultural treasures, art, entertainment, educational purposes, medical imaging, surgical assistance, big data visualizations, and computer aided design.

However, digital holograms can only convey as much information because of their large space-frequency bandwidths resulting in resolutions of several gigapixel. Thus compression becomes a necessity, especially for dynamic content. As holograms of visible light are based on the interference of diffracted coherent 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 facts together 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.

During my PhD research I design such strategies and provide a first proposition of a holographic video codec suitable for multiple-independently objects. Most contributions exploit heavily the concepts of spatial frequency (number of lines per unit length) and optical phase-space (also known as space-frequency or time-frequency domain).

I am also interested in the objective quality assessment of digital holograms, computer generation of digital holograms, and the study of speckle denoising of the back-propagated wave fields with the objective to find low-complexity algorithms with acceptable visual performance.

  • Optical Society of America
  • imec