Hand motion tracking based on a constraint of three-dimensional continuity

We propose to set a 3-D search volume for tracking a 3-D palm motion efficiently using two cameras. If we perform template matching for right and left images independently, two points in two images do not always correspond to each other. Then, we cannot always track the correct 3-D position. Instead of finding the corresponding point in each image, we set the search volume in the 3-D space, not in the 2-D image planes, so that only valid 2-D pairs are considered in the proposed search process. The tracking process is as follows. First, we set the search volume. The 3-D coordinates of the search volume are projected on two in each image plane. We perform template matching at the projected pixel in each image. The similarity of the 3-D position is computed from two dissimilarities in the two images. We search for the position that has the maximum similarity in the search volume, and we obtain the correct correspondence result. We incorporate this technique into our tracking system, and we compare the proposed method with a method that tracks a palm motion without epipolar constraint. Our experimental results show that use of the proposed 3-D search volume makes the method accurate and efficient for tracking the 3-D motion.