关键词: 脉冲噪声, 开关中值滤波, 噪声检测, 局部能量

Abstract: To remove the impulse noise from the image，on the basis of research for the previous switching median filters，an improved median filtering algorithm based on two-stage noise detection is proposed.This algorithm analyzes and overcomes the shortcoming of the local extremum misjudgement of the max-min noise detector by adding the second noise detection with the local energy of image pixel.The noise pixels are removed using the improved median filtering，while signal pixels hold their gray value and are unprocessed.Simulation results show that this algorithm has the ability of removing noises and the ability of preserving the partial details of images in comparison with some recent methods especially when the noise density is very high.

Key words: impulse noise, switching median filter, noise detection, local energy