Error Backprojection Algorithms for Non-Line-of-Sight Imaging

Recent advances in computer vision and inverse light transport theory have resulted in several non-line-of-sight imaging techniques. These techniques use photon time-of-flight information encoded in light after multiple, diffuse reflections to reconstruct a three-dimensional scene. In this paper, we propose and describe two iterative backprojection algorithms, the additive error backprojection (AEB) and multiplicative error backprojection (MEB), whose goal is to improve the reconstruction of the scene under investigation over non-iterative backprojection algorithms. We evaluate the proposed algorithms’ performance applied to simulated and real data (gathered from an experimental setup where the system needs to reconstruct an unknown scene). Results show that the proposed iterative algorithms are able to provide better reconstruction than the unfiltered, non-iterative backprojection algorithm for both simulated and physical scenes, but are more sensitive to errors in the light transport model.This work was supported by DARPA REVEAL Program (Grant no. DARPA-BAA-15-44 MSN189781), NASA NIAC Program (Grant no. NNH15ZOA001N-15NIAC A2) AFRSO (Grant no. AFOSR-2014-0003-cidYIP-2015), ONR (Grant no. Open BAA 15-001), and Morgridge Institute for Research