The Research On Resampling Detection Of Digital Image Passive Forensics

The advent of digital equipment and sophisticated image editing software has not only brought large convenience,but also make some digital images being modified more and more easy.Those images which have been revised and misrepresented evilly may appear in various areas, such as news,judicial impartiality and scientific research. This kind of phenomenon can destroy the normal social order for some countries or governments,even can bring the worrisome adverse effects to our life and work. Therefore, the digital images evidence-collecting technology to obtain evidence for judging their originality, becomes a hot research field.In this paper, according to research on resampling detection of digital image passive forensics. Introducing the basic principles of resampling algorithms and statistical properties for resampling images, the algorithm mainly use the second derivative periodicity of interpolation signal to detect resampling images. Analyzed the following five aspects of image detection:Firstly, based on analyzing theoretical background, the significance, research status at home and abroad,discussing the principle and feature of digital image passive forensics. Some general methods were given. Periodic correlation of re-sampled pixels is employed to analyze the principle of signal resampling and image resampling.In order to analyze the best algorithm in this paper, two commonly methods of resampling were discussed. Moreover, according to analyze the periodicity of interpolating signal and then estimate scaling ratio of the image. Comparing the spectrum characteristics of each block after partitioning an image into small overlapping blocks for judging whether the image was spliced,then, tampered regions can be identified.Due to the current resampling detection algorithms mainly applied to lossless compression, an algorithm which overcomes a detection limititation of similar statistical properties between pixels in lossy compression and resampling operation is proposed in this paper.Then it is capable to detect resampling efficiently in JPEG compressed images.At the end of this paper, we summarize whole of the thesis and the prospective developing of digital image passive forensics in the future.