JPEG quality estimation using simple least squares matching of quantization tables

Adapted from Quality Coal by Greenville Daily Photo . Used under CC0 1.0. license . In my previous post I addressed several problems I ran into when I tried to estimate the “last saved” quality level of JPEG images. It described some experiments based on ImageMagick ’s quality heuristic, which led to a Python implementation of a modified version of the heuristic that improves the behaviour for…