Random-valued impulse noise detector for switching median filters using edge detectors

This paper talks about a random impulse-noise detection scheme that was developed to be used as the first stage of a switching median filter. First by using an edge detector with a dynamic threshold, hidden artifacts are revealed by gradually changing the threshold of the edge detector. Then by applying a series of masks to the edge maps, the artifacts are pinpointed and tabulated. By analyzing the statistical data, the intensity of the random impulse noise corrupting a pixel is estimated. This information can then be passed on to an adaptive noise reduction filter that can eliminate it with a correlated intensity.