Accurate detection of demosaicing regularity from output images

Demosaicing regularity is an important processing regularity associated with the internal camera processing and its detection from output photos is useful for non-intrusive forensic engineering. In this paper, we propose a reverse grouping technique to improve the detection accuracy of our earlier proposed detection model based on second-order image derivatives. Comparison results based on syntactic images shows that the proposed technique significantly reduces the reprediction errors for some commonly used demosaicing algorithms. When applied to a real application, i.e. camera model identification, our demosaicing features in conjunction with probabilistic support vector machine classifier achieve excellent classification performance.