Research on removing noise in medical image based on median filter method

Removing salt-and-pepper noise in medical images plays a very important role for the preprocessing modules of virtual endoscope system. Traditional median filter and an adaptive median filter are implemented, and their effectivity on denoising is evaluated by PSNR and destroyness degree of noise to original image. Research and analyze the influence of the filter window size and the spatial density of noise on the quality of denoised image also. Simulation results based on Matlab show that the two methods can eliminate the salt-and-pepper noise in CT and MRI medical images and preserve the edges and detail information of the objects. Both of the two methods have been used in the virtual endoscope system, and the filtering performance is very satisfactory.