Various methods to determine image quality using OpenCV. Method to detect scene text, watermarks, image blur, and image 'naturalness' via BRISQUE method.
Look at client code for usage.
BRISQUE Paper: Blind/Referenceless Image Spatial Quality Evaluator.Signals, Systems and Computers (ASILOMAR), 2011 Conference Record of the Forty Fifth Asilomar Conference on. Mittal, A. ; Moorthy, A.K. ; Bovik, A.C.
SVM.NET Library: http://www.matthewajohnson.org/software/svm.html
BRISQUE code ported from: https://github.com/pbypby/BRISQUE