Re-sampling detection in information forensics
信息取证中图像重采样检测

A digital image generated by re-sampling is the combination of the original image signal and periodical signal. Through the analysis of the two original signals by using EM algorithm, the traces of re-sampling could be detected. Through the modification of the present model, the uniform distribution was supplanted by the original image distribution and a priori probability updating was added in order to approach the realistic distribution. The possible singular points during the EM iterations were avoided by adding a small threshold. Experiment results demonstrate the effectiveness of the modified model in detecting image re-sampling. Furthermore, it can detect re-sampling traces on uncompressed bmp or tiff images, and it even can detect whether an image is JPEG compressed accurately.