Method, system and apparatus

In block-based motion or depth estimation, a block is assigned a motion or depth value as a result of minimizing the matching error over a limited set of candidate values (21, 22, 23, 24). The curvature (20) of the function of matching error against candidate value, based on this set, can be used as a measure for the strength of the obtained optimal candidate value for motion or depth. If the obtained value is not sufficiently strong, the method and system according to the invention will repeat the process of determining the optimal candidate value until a sufficiently strong value is obtained. An apparatus for adapting a video signal (40) uses the chosen candidate values to create an enhanced version of the video signal (40).