Directional difference-based impulse detector and median filter

A novel median-based filter having the effectiveness in the removal of impulse noise with high probability is proposed in this paper. The proposed filter is a kind of switching scheme-based median filters, and consists of two main parts: one detects impulse noise (impulse detecotor), another removes impulse noise (noise removal filter). First, we propose a novel impulse detector based on the directional difference algorithm we have proposed. Next, a novel median-based filter, where the output of the directional difference filter is introduced into the filtering operation, is proposed. Experiment results demonstrate that the proposed impulse detector and noise removal filter are better than the conventional detectors and median-based filters, respectively. Moreover, we show through the restoration images that the proposed filter has effectiveness even for highly corrupted images.