A new ASIC capable of computing rank order "lters, weighted rank order "lters, standard erosion and dilation, soft erosion and dilation, order statistic soft erosion and dilation, fuzzy erosion and dilation and fuzzy soft erosion and dilation is presented in this paper. Its function is based on local histogram and a successive approximation technique and performs on 3;3-pixel image windows. The hardware complexity of the proposed structure is linearly related to both image data window size and pixel resolution. The dimensions of the core of the proposed ASIC are 2.88 mm; 2.8 mm"8.06 mm and its die size dimensions are 3.72 mm;3.64 mm"13.54 mm. It executes 3.5;10 non-linear "lter operations per second. 2000 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.