Is there a program to automatically evaluate the visual quality of JPEG images?

Question

JPEG

It is necessary to go through a bunch of small JPEG files, note those where the visual distortion from compression is significant enough to be noticeable and replace them with new ones (generated from the originals using a lower compression ratio). Is it possible to automate this somehow? It is clear that this is a subjective matter, but it seems to me that it is not far in nature from the banal OCR.

Answer 1

JPEG compresses in blocks of 8x8 pixels. The stronger the compression, the more pronounced the boundaries, due to the increase in high-frequency noise. We need to dig in this direction. I know for sure that before, for example, all sorts of jpeg quality "enhancers" first of all eliminated the borders of these 8 pixel blocks.