# Peak Signal-to-Noise Ratio (PSNR) in Image using OpenCV and Matlab



Peak signal-to-noise ratio (PSNR) shows the ratio between the maximum possible power of a signal and the power of the same image with noise. PSNR is usually expressed in logarithmic decibel scale.

$$MSE =1/m*n \sum_{i=0}^{m-1} \sum_{j=0}^{n-1} [ Image( i,j) -NoisyImage( i,j) ] ^2$$
$$PSNR =10* \log_{10} \Bigg(MAXI^2/MSE\Bigg)$$

MSE is Mean Square Error and MAXI is the maximum possible pixel value of the image. For instance if the image is uint8, it will be 255.

Ref [1],[2], [3], 4