SymStereo: Stereo Matching using Induced Symmetry

摘要

Stereo methods always require a matching function for assessing the likelihood of two pixels being in correspondence. Such functions, commonly referred as matching costs, measure the photo-similarity (or dissimilarity) between image regions centered in putative matches. This article proposes a new family of stereo cost functions that measure symmetry instead of photo-similarity for associating pixels across views. We start by observing that, given two stereo views and an arbitrary virtual plane passing inbetween the cameras, it is possible to render image signals that are either symmetric or anti-symmetric with respect to the contour where the virtual plane meets the scene. The fact is investigated in detail and used as cornerstone to develop a new stereo framework that relies in symmetry cues for solving the data association problem. Extensive experiments in dense stereo show that our symmetry-based cost functions compare favorably against the best performing photosimilarity matching costs. In addition, we investigate the possibility of accomplishing Stereo Rangefinding that consists in using passive stereo to exclusively recover depth along a pre-defined scan plane. Thorough experiments provide evidence that stereo from induced symmetry is specially well suited for this purpose.