Abstract: Edge-aware smoothing is important for many image editing applications as well as image preprocessing．Edge preservation and detail suppression form a contradictory pair．An edge-preserving smoothing algorithm was proposed,in which a signal is asked to attain its extrema at some given points．By manipulations on extrema of the resulting image,significant edges are retained,and at the same time,side edges and small fluctuations are subdued．Our method first obtains a preliminary smoothing version,whose extrema are used as constraints on the resulting image．Among all functions that meet these constraints,we pursued the one that is most similar to the original signal as the smoothing result．This optimization problem is solved by the half-quadratic technique and alternating minimization．Experimental results show that applications such as detail enhancement can benefit from the better performance of our method for preserving edges.

Key words: Image smoothing algorithm,Edge-preserving image smoothing,Image filtering