Angular multichannel sigma filter

Adaptive nonlinear filtering methods are preferred in situations when it is necessary to adapt a filter behavior for varying signal and noise statistics. In the case of impulsive noise corruption, the problem is stated often as searching for the switching function that allows the filtering effect only to noisy samples. Thus, the undesired smoothing of non-corrupted image areas, which results in blurring, especially of small image structures and details, is reduced. We provide a new adaptive framework between a basic vector directional filter and an identity operation based on the angular multichannel definition of J.S. Lee´s sigma filter (see Comp Vision, Graphics, Image Proc., vol.24, no.2, p.255-69, 1983).