关键词: 椒盐噪声, 高斯噪声, 灰度极限, 脉冲耦合神经网络, 均值滤波, 可变步长

Abstract: A new method of filtering mixed noise based on limited grayscale and Pulse Coupled Neural Network (PCNN) was proposed for an image contaminated by salt and pepper noise and Gaussian noise. First, salt and pepper noise was identified according to the limited grayscale in a detecting window. Then the noise was filtered via mean filter in a filtering window. Subsequently, Gaussian noise was identified by using the time matrix of PCNN. Finally the Gaussian noise was filtered by some different filters based on variable step. The experimental results show that the proposed method has more advantages not only in filtering effects but also in objective evaluation indexes of Peak Signal-to-Noise Ratio (PSNR) and Improved Signal-to-Noise Ratio (ISNR) compared to some traditional methods.

Key words: salt and pepper noise, Gaussian noise, limited grayscale, Pulse Coupled Neural Network (PCNN), mean filtering, variable step