A general form of illumination-invariant descriptors in variational optical flow estimation

Abstract

This paper introduces a generalized descriptor formulation facilitating the design of illumination invariant data-terms in variational optical flow. This contribution also proposes a criterion to check whether a patch-based descriptor is illumination invariant or not. To do so, a local model is used to simulate complex illumination changes between images. As an example, it is shown how a novel patch-based descriptor can be derived from the generalized form. The performances of this descriptor are compared to those of reference descriptors in the literature using data sets with and without strong illumination changes. The accuracy and robustness of the proposed descriptor is also demonstrated through tests on gastroscopic image sequences including complex illumination changes.