Median Filter Method And Its Applications For Image Processing

During the forming, transferring and memorizing of the digital images, the images are often corrupted by different kinds of noises because of the defection of the imaging system, transferring medium and memorizing equipment. Therefore, in the fields of pattern recognition, computer vision, image analyzing and video coding, the early vision processing is very important. The result of it will directly affect the quality and outcoming of the later processing.Different from the linear filter, the non-linear filter can not only remove noise effectively but also keep the details of the digital images, so images can be clearer and more vivid. As an effective processing technology, the non-linear filter is widely used in the digital image processing. Median filters are representative. The typical median filter can remove the impulse noise, but it also corrupts some very important details of the images. There are many improved median filters firstly suggested to overcome the problems. Three new median filters are proposed in this paper, such as the effective and non-iterative removal based on the threshold for salt-and-pepper noise from images, non-iterative removal based on the directional information for salt-and-pepper noise from images, an improved anisotropic diffusion based on the median filter. From the theoretical analysis and experimental results in matlab show the efficiency of these new ideas.