Integrating Motion and Illumination Models for 3D Tracking
One of the persistent challenges in computer vision has been tracking objects under varying lighting conditions. In this paper we present a method for estimation of 3D motion of a rigid object from a monocular video sequence under arbitrary changes in the illumination conditions under which the video was captured. This is achieved by alternately estimating motion and illumination parameters using a generative model for integrating the effects of motion, illumination and structure within a unified mathematical framework. The motion is represented in terms of translation and rotation of the object centroid, and the illumination is represented using a spherical harmonics linear basis. The method does not assume any model for the variation of the illumination conditions - lighting can change slowly or drastically. For the multi-camera tracking scenario, we propose a new photometric constraint that is valid over the overlapping field of view between two cameras. This is similar in nature to the well-known epipolar constraint, except that it relates the photometric parameters, and can provide an additional constraint for illumination invariant multi-camera tracking. We demonstrate the effectiveness of our tracking algorithm on single and multi-camera video sequences under severe changes of lighting conditions.