Selective switching median filter for the removal of salt & pepper impulse noise

In this paper, a new median based filtering algorithm is presented for the removal of impulse noise from digital images. A good analysis of the limitations of the top ranking median filters, the progressive switching median filter, PSMF and the rank-order based adaptive median filter, RAMF is made and are overcome very effectively by the proposed filter which cleans the impulse corruptions of a digital image in two distinct phases of impulse detection and impulse correction. The detection phase identifies the corrupted pixels into a flag image by a spatial rank ordered approach and the correction phase modifies the corrupted pixels identified in the flag image by a more suitable rank ordered value by considering the neighboring features. The filter shows better performance than most other impulse filters, and in particular, that of the top ranking RAMF and PSMF in terms of computational aspect and objectively. The filtering technique gives good results with less patchy effects from images corrupted at higher noise levels and the results are more appealing with good fidelity at lower noise levels