Big in SSIM implementation, don't use this code for perceptual quality estimation about pytorch-msssim HOT 3 OPEN

Thank you for raising this issue. I will look into adding an optional flag that applies the correct average pooling before the SSIM computation. Note that this is also an issue on the original SSIM from which this repository was forked so you may want to raise this issue there as well.

I will leave the issue open until this is resolved in master.

from pytorch-msssim.

I don't think it's an error per say, it's not very explicitly mentioned in the paper either, although during the experiments the authors did mention that they downsampled the images. In addition there are two implementations by the author here: http://www.cns.nyu.edu/~lcv/ssim/, with the second implementation similar to the first but with an additional preprocessing step. Nevertheless, I think it's good to take note of this for any perceptual quality tasks:)

from pytorch-msssim.

While it's not an error, usage of SSIM without preprocessing leads to a significantly worse performance as a "perceptual quality estimator" which is 90% of its use cases nowadays.

from pytorch-msssim.