关键词: 自适应, 中值滤波, 块均匀度, PSNR

Abstract: A new adaptive median filter algorithm was proposed.By a 3×3 window sliding in the original image the block uniformity of the window was calculated and was compared with the block uniformity of the entire image，therefore，the window center pixel was adaptively determined whether it was a noise；The number of noises in the 3×3 window was counted so that the filter window size was adaptively adjusted；The weighted value of each pixel in the filter window was adaptively calculated and the improved median filter method was used to eliminate noise pixels.This algorithm can effectively remove noises and also retain image details very well.According to the further analysis of experimental results，it is shown that the proposed algorithm is superior to the traditional mean filter algorithm and median filter algorithm，under the same intensity of pepper and salt noises，with 9.4 to 12.7 improvement of PSNR．The evaluation results coincide with the visual effect very wel1.It also provides a new way for image filtering.

Key words: adaptive, median filter, block uniformity, PSNR