Improving Robustness to Out-of-Distribution Data By Frequency-Based Augmentation

The estimation of the misalignment between consecutive JPEG compressions is a really important task that can be useful in forensics investigation for first quantization matrix estimation and forgery localization. Based on the analysis of DCT histograms obtained applying a third compression, an effective shift estimation solution has been designed. Moreover, to increase the overall robustness in challenging conditions (e.g., small patches) several fusion strategies combining all the DCT coefficient information have been investigated. Finally, the effectiveness of the proposed solution has been demonstrated considering several scenarios (i.e., different patch sizes and quantization matrices) and comparisons with state-of-the-art solutions.