How to programmatically determine the quality of a photo?

Question

Algorithms

Are there methods to programmatically determine which of the two photos is better in quality? The same photo is scanned on two different scanners in different places and under different conditions. You need to add the best scan to the database.
Example from the Internet:
The left photo should be added.
Thank you!

Answer 1

To assess sharpness, you can use the histogram of gradients, as in this topic habrahabr.ru/post/175717

Answer 2

You can try to analyze the amplitude of the "medium" frequencies in any two-dimensional harmonic transformation (Fourier, Haar and other wavelets). Where the amplitude is higher - there is more information capacity.
It is better not to consider the upper frequencies - otherwise the photo noisy with small noise will give high performance.

Answer 3

You can come up with your own metric, for example, how different are the colors of pixels in different squares. Or train a neural network. In any case, you will need a large test set (at least 1000 pairs of photos) to test the algorithms.

Answer 4

when there is something to compare with, then in principle you can still decide, but when there is only one photo, let's say only (B), then you will not determine what quality it is.