Computational Imaging for Scene Understanding

7Far Infrared Light Transport Decomposition and Its Application for Thermal Photometric Stereo

Kenichiro TANAKA

Vision and Imaging Group, Ritsumeikan University, Shiga, Japan

7.1. Introduction

Light transport is a study of the complex interaction between light and matter. Decomposing light transport powers low-level computer vision tasks that range from shape recovery to reflectance estimation. Previous work has studied light transport at visible light wavelengths; here, we lay the foundation for light transport at long-wave infrared wavelengths. At these wavelengths, light transport is very unique due to the interplay between heat and long-wave infrared light.

Previously, color (Shafer 1985), polarization (Treibitz and Schechner 2009) and active illumination (Nayar et al. 2006) have been used for light transport decomposition. The transient behavior of optical components varies in the order of tens of picoseconds (Wu et al. 2014), thus paving the way for time-resolved approaches. So far, multiple time-resolved approaches have been proposed – with the use of a femto-pulsed laser, interferometer (Gkioulekas et al. 2015), time-of-flight camera modifications (Heide et al. 2013; Kadambi et al. 2013; Kitano et al. 2017) and single-photon sensor (O’Toole et al. 2017).

Unlike visible light imaging, time-resolved light transport decomposition using thermal imaging is feasible at a video frame rate. This is because of the important observation that the speed of heat propagation is ...