>>25
What about comparing quality using OpenCV? (yes some involve machine learning)
https://github.com/opencv/opencv_contrib/tree/master/modules/quality
https://github.com/andrewekhalel/sewar/blob/master/sewar/no_ref.py
https://github.com/arcaduf/image_quality_assessment/tree/master/metrics
Here is an article in one of the common method
https://towardsdatascience.com/automatic-image-quality-assessment-in-python-391a6be52c11