DETAIL-PRESERVING MEDIAN BASED FILTERS IN IMAGE-PROCESSING

A switching scheme for median filtering which is suitable to be a prefilter before some subsequent processing e.g. edge detection or data compression is presented to remove impulse noises in digital images with small signal distortion. The switching procedure is based on the local measurements of impulses which is called impulse detection. A median and weighted median based impulse detector is devised and the relevant properties are discussed. By using a test image, we demonstrate that the filtering structure yields an output image which is significantly better than those of median, weighted median and optimal stack filters.