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Exploiting light and material interaction

Periodic Reporting for period 4 - lightMaterInt (Exploiting light and material interaction)

Reporting period: 2019-09-01 to 2021-08-31

The interaction between light and material leads to beautiful visual phenomena that greatly enrich our perception of the
world. The ability to measure and model light scattering is central to almost any field of science. However, light transport
in rich scenes is a complex process involving a long sequence of scattering events. Computationally modeling, reproducing
and acquiring the processes generated so easily by Mother Nature is an extremely challenging task. While several computational
models have been proposed, they are all making various simplifying assumptions that cannot capture the full
complexity of light transport processes in nature. In the proposed research, we suggest new measurement strategies and
new inference algorithms that will allow us to infer more information on light and material interaction.
Specifically, the research will focus on the following tasks: (i) Acquiring internal sub-scattering, and recovering the volumetric
structure of partially translucent objects using transient imaging data; (ii) Acquiring external illumination from
its reflection on diffused objects; (iii) Exploiting illumination for developing digital light sensitive displays, capable of
presenting 3D scenes with spatially varying reflectance properties.
As light scattering is such a fundamental phenomenon, our envisioned new tools have applications in almost any field of
science, from astronomy to microscopy, and in medicine. We plan to push the bound on the penetration depth of medical
imaging devices, and allow chemists to infer more information on material decomposition through scattering. In earth
science we can infer aerosol density from the scattering of sunlight in the atmosphere and ocean, a central challenge in any
study of climate and pollution. In addition, we will pursue new technological developments such as light sensitive displays,
offering a novel form of immersive visual experience, and new technologies of coded security cameras.
The project covers research on light sensitive display and on volumetric reconstruction using inverse scattering.
This also leaded to interesting research on the modeling of speckle statistics in random media, resulting in new tools with wide applications, far beyond the original goals of this project.
During the second part of the project we plan to apply speckle rendering tools to inverse rendering problems and to the volumetric reconstruction of scattering materials.