Naik, N. "Multibounce Light Transport Analysis using Ultrafast Imaging for Material Acquisition"

Abstract

This thesis introduces a novel framework for analysis of multibounce light transport using time-of-flight imaging for the applications of ultrafast reflectance acquisition and imaging through scattering media. We demonstrate the use of light indirectly scattered off materials as a tool for measuring material appearances and other scene properties. We propose an linear-system based mathematical framework which can recover scene characteristics using a wide array of optimization and linear algebra tools.

In particular, we develop the concept of of time-of-flight reflectance estimation, and demonstrates a new technique that allows a camera to rapidly acquire reflectance properties of objects from a single viewpoint, over relatively long distances and without encircling equipment. We measure material properties by indirectly illuminating an object by a laser source, and observing its reflected light indirectly using ultrafast imaging. As compared to lengthy or highly calibrated reflectance acquisition techniques, we demonstrate a device that can rapidly, on the order of seconds, capture meaningful reflectance information.

Furthermore, we use this framework to develop a method for imaging through scattering media using time-of-flight cameras. We analyze diffuse scattering to recover albedo and depth information of planar objects imaged through a scattering medium. The methods developed in this thesis can spur research with novel real-time applications in Computer Graphics, Medical Imaging and Industrial Photography.