Howtosignalprocessing
What does SSIM measure?
The structural similarity index measure (SSIM) is a method for predicting the perceived quality of digital television and cinematic pictures, as well as other kinds of digital images and videos. SSIM is used for measuring the similarity between two images.
Why is SSIM better than MSE?
MSE will calculate the mean square error between each pixels for the two images we are comparing. Whereas SSIM will do the opposite and look for similarities within pixels; i.e. if the pixels in the two images line up and or have similar pixel density values.
What is Psnr and SSIM?
Peak signal to noise ratio (PSNR) and structural index similarity (SSIM) are two measuring tools that are widely used in image quality assessment. Especially in the steganography image, these two measuring instruments are used to measure the quality of imperceptibility.
Can SSIM be negative?
Edit: As I mentioned in the comments SSIM can be negative, and it is caused by the covarience of the two images that can be negative. In the Skimage SSIM source code, Covarience of the two images is represented by vxy, and it can be negative in some cases.
