ECHO · Practical Imaging and Inversion of Transient Light Transport

The automated analysis of visual data is a key enabler for industrial and consumer technologies and of immense economicand social importance. Its main challenge is in the inherent ambiguity of images due to the very mechanism of imagecapture: light reaching a pixel on different paths or at different times is mixed irreversibly. Consequently, even afterdecades of extensive research, problems like deblurring or descattering, geometry/material estimation or motion trackingare still largely unsolved and will remain so in the foreseeable future.Transient imaging (TI) tackles this problem by recording ultrafast optical echoes that unmix light contributions by the totalpathlength. So far, TI used to require high-end measurement setups. By introducing computational TI (CTI), we paved theway for a lightweight capture of transient data using consumer hardware. We showed the potential of CTI in scenarios likerobust range measurement, descattering and imaging of objects outside the line of sight – tasks that had been considereddifficult to impossible so far.The ECHO project is rooted in computer graphics and computational imaging. In it, we will overcome the practical limitations that are hampering a large-scale deployment of TI: the time required for data capture and to reconstruct thedesired information, both in the order of seconds to minutes, a lack of dedicated image priors and of quality guarantees forthe reconstruction, the limited accuracy and performance of forward models and the lack of ground-truth data andbenchmark methods.Over the course of ECHO, we will pioneer advanced capture setups and strategies, signal formation models, priors and numericalmethods, for the first time enabling real-time reconstruction and analysis of transient light transport in complex and dynamicscenes. The methodology developed in this far-reaching project will turn TI from a research technology into a family ofpractical tools that will immediately benefit many applications.