In this paper

a novel approach is proposed for removing and restoring random-valued impulse noise and preserving fine details at the same time.The impulse noise detection technique is presented

which is based on the so-called peer group concept.A pixel is noise-free only when its peer neighbor number is local maximum or large.Extensive simulations show that the proposed filter provides better performance than many of the existing filters and the computational complexity is lower than many of the median-based filters.In particular

the threshold is adaptive to different image types.