Evaluation of edge detectors performances with a discrete expression of Canny´s criteria

Three quality criteria have been defined by Canny (1986) to deduce an optimal edge detector in the continuous space domain. In this paper, we give an equivalent for these criteria in the discrete space domain. These new criteria are better in accordance with experimental results than previous one. Furthermore, they are more suitable to compare filters performances. We explain how to compute them. We compare some edge detectors. Finally, we use them to prove the qualities of a new simpler implementation of a second order recursive smoothing filter issued from Canny´s theory