Comment by godelski

> If they applied a perfect digital gaussian-blur, then that is reversible

Actually any noise distribution is frequently reversible if you know the parameters and number of steps. This is in fact how diffusion models work (there's even work of Normalizing Flows removing realistic camera noise). It is just almost impossible to figure this out since there are many equivalent looking ways. But we need to be clear that there is a difference between reversibility and invertibility. A invertible process is bijective, or perfectly recreates the original setting. A reversible process can just work in both directions and isn't guaranteed to be invertible. (Invertible means reversible but reversible doesn't mean invertible)[0]

I bring this up because even more complicated versions of bluring could be argued as not "faked" but rather "enhanced." A better way to test Samsung faking the data is to mask out regions. If the phone fills in the gaps then it is definitely generating new data. This can still be fine if the regions are small, unless we also want to call bilinear interpolation "faked" but I don't think most people would. This is why it gets quite difficult to actually prove Samsung is faking the image. I don't have a Samsung phone to test this though.

So basically I'm with you, and even a slightly stronger version of this

> It is not totally inconceivable that the AI model could have learned to do this deconvolution with the Gaussian blur function, in order to recover more detail from the image.

Edit: After reading other comments I wanted to bring some things up.

- The down scaling is reversible, but not invertible. We can upscale, reversing the process. But yes, there is information lost. But some data can still be approximated and/or inferred.

- The clipping experiment isn't that good. Honestly, looking at the two my brain fills in the pieces and they look reasonable to me too. Clipping the brightness isn't enough, especially since it is a small portion of the actual distribution. I did this on both the full image and small image and both are difficult to distinguish by eye from the non-clipped. Clipping below 200 seems to better wash out the bottom of the moon and remove that detail. 180 seems better though tbh.