Analysis and Elimination of Multi-Path Interference in AMCW Lidar Systems Using Trigonometric Moments

AMCW lidar systems (also known as photonic mixer devices) provide affordable full-field range imaging at high frame rates for applications such as natural user interaction or fast geometry acquisition. They work by determining how long light takes to fly from an active illumination into the scene and back to the camera. However, the assumption of a single time of flight per pixel is inadequate in reality. Global illumination effects lead to light paths of varying length which interfere and lead to strong, systematic distortions in range images. After an introduction to the field, my talk will focus on the analysis and elimination of these effects. I demonstrate how a specific measurement procedure turns the corresponding reconstruction problem into a trigonometric moment problem. These problems are well-studied and powerful closed-form solutions exist. The resulting techniques serve to reconstruct complex impulse responses from measurements at few (e.g. three) frequencies. Besides applications in range imaging, this can also be used for fast transient imaging. The research further opens up new ways to analyze the reconstruction problem leading to fundamental statements on the achievable accuracy that are independent of the chosen solution. Most of the presented work has been published at SIGGRAPH Asia 2015.