单幅图像的噪声估计对于评价图像以及光学成像系统质量非常重要。提出了一种基于RGB 三通道噪声散点统计累计的无参考型图像噪声水平估计方法。图像经过对比敏感函数滤波(CSF) ，以获取符合人眼观察的图像。图像被分水岭法分割成不同内容区域子块，并对各子块区域进行仿射重建以实现无噪图像的估计。通过含噪图像与无噪估计图像的比较，求取子块的强度与噪声对，获得RGB 三通道的强度噪声对散点图。通过对噪声统计累计值的分析，实现噪声水平的估计。实验采用了通用数据库对所提方法进行了测试，并与其他方法进行了对比分析，实验数据表明，本文方法在噪声估计上实现了主客观评价的一致。

Single image noise estimation is important for evaluating image and optical imaging system. A no-reference image noise estimation approach based on noise scatter statistics and accumulation of RGB three channels is proposed. An image is filtered by contrast sensitivity function (CSF) to match the human visual system, and the image is segmented by watershed method into sub-image patches with different contents, different patches are achieved free noise estimation using affine reconstruction. Then the pairs of intensity and noise are calculated for patches, and a scatter diagram for RGB three channels of intensity and noise is obtained. Through noise statistics and accumulation , the noise level estimation is achieved. The general database is applied to test the proposed method and other methods in the experiment. Experimental results indicate that the proposed method achieves the same evaluation both objective and subjective.