针对非局部均值图像去噪算法在边缘处权值的不合理性,结合双边滤波算法,改进了权值函数。分析了空域中各种去噪算法中权重计算方法,指出非局部均值算法中权重计算方法不能区分边缘两边图像块对边缘处图像块的差异。为了度量这种差异,本文算法借鉴双边滤波思想,强调图像块中心像素地位,改进了权重函数。大量去噪实验结果表明,本文算法去噪后的PSNR值比经典NLM算法有较大改进,比最新改进NLM算法也有一定提高。

The weight function of the non-local means denoising method has a certain degree of irrationality at edges,in which cannot distinguish between the denoising roles of the patches at the two sides of an edge. However,when the center pixel of the patch gets more attention,the different denoising roles can be measured. In the light of the bilateral filtering method,the weight function of the non-local means method is revised. Experimental results on several images show that our new method greatly outperforms the classical non-local means method,and it has certain advantages over the latest improved non-local means method.