Abstract

This paper describes a method to recover scene geometry from the second-bounce of light transport. We show that form factors (up to a scaling ambiguity) can be derived from the second-bounce com- ponent of light transport in a Lambertian case. The form factors carry information of the geometric relationship between every pair of scene points, i.e ., distance between scene points and relative surface orienta- tions. Modelling the scene as polygonal, we develop a method to recover the scene geometry up to a scaling ambiguity from the form factors by optimization. Unlike other shape-from-intensity methods, our method si- multaneously estimates depth and surface normal; therefore, our method can handle discontinuous surfaces as it can avoid surface normal inte- gration. Various simulation and real-world experiments demonstrate the correctness of the proposed theory of shape recovery from light transport.