关键词: 像素离群度, 非局部均值算法, 区域阈值, 信噪比

Abstract: The pixel quotient is combined with traditional nonlocal means algorithm, putting forward a kind of improved nonlocal means filtering algorithm. That is Q-NLM. In allusion to the problem of the impulsive noise in the traditional nonlocal means algorithm, the concept of the pixel quotient Q is come up with. It is used for judging the similarity of the initial pixel and impulse noise, and according to the calculated Q to divide pixel areas, the median filter is brought in to remove impulse noise points while adjusting different area threshold. Thus it can further reduce the influence of the mixed noise on filter in medical images. The relevant simulation experiment results show that the combination of the pixel quotient with traditional nonlocal means algorithm can improve the image PSNR, effectively keep the details of CT image while removing the mixed noise.

Key words: pixel quotient, nonlocal means algorithm, area threshold, signal to noise ratio