Robust nonlinear contrast enhancement filters

This paper is devoted to a new adaptive class of nonlinear contrast enhancement filters. These filters are referred to as nonstationary filters because the filter mask depends on the local pixel values. First we show how to find the adaptive filter mask, i.e. the set of surrounding pixels the more similar, in a sense which is defined, to the current pixel. Then we define a new class of quadratic filters based on the so defined filter mask. Finally, processing of blurred and noisy images by these algorithms demonstrates the contrast enhancement improvement in comparison to other quadratic filters