Quality evaluation of motion estimation algorithms based on structural distortions

In this paper a methodology for understanding the effectiveness of motion estimation techniques is presented. Unlike other performances evaluation systems, that are based on measuring the errors between the actual and the predicted displacements, the proposed technique is inspired to the Human Visual System. More in detail, the perceptual impact of geometric distortions induced by non accurate motion estimation is considered by means of an objective measure of the perceived distortion impact. Some of the most common block-based motion estimation algorithms have been tested. For each of them the performances have been evaluated by comparing the proposed metric with the state of the art metrics. A subjective experiment has been performed to assess the effectiveness of the estimation algorithms from a perceptual point of view. The obtained results show that the scores obtained with the tested metrics generally do not match with the perceived quality, while the proposed methodology does. Therefore, the presented tool can be used in the design and in the verification of a generic motion estimation algorithm.