• Median filtering is a common nonlinear method for noise suppression that has unique characteristics.
• Large discontinuities such as edges and large changes in image intensity are not affected in terms of gray-level intensity by the median filter, although their positions may be shifted by a few pixels.
• This nonlinear operation of the median filter allows significant reduction of specific types of noise.
• For example, “pepper-and-salt noise” may be removed completely from an image without attenuation of significant edges or image characteristics.