Review of methods for resolving multi-path interference in Time-of-Flight range cameras

Abstract

Time-of-Flight range cameras measure the distance from the camera to the objects in the field of view. This is achieved by illuminating the scene with amplitude modulated light and measuring the phase change in the modulation envelope between the transmitted and received light, simultaneously for each pixel. A major cause of accuracy errors are multiple propagation paths between the light source and pixel. This error is highly scene dependent and can be substantial. In this paper we review the state of art in multi-path interference correction. Two mathematical models dominate the literature, a sparse formulation from discrete paths and a lambertian inter-reflection model. The recovery methods for the sparse formulation are effective at looking through a translucent sheet, while lambertian model based techniques can reduce the errors due to inter-reflections in a corner.