The Research On Passive Blind Forensics Detection Of JPEG Image

With the rapid development of internet technology，powerful image processing andediting software have made it much easier to change image. If the tampered images are usedin various areas, such as news or laws, they will do a lot of bad influences in the normal sociallife. Therefore, the passive forensic technology of digital image becomes the focus of research.As the most widely used image format，JPEG has become an important object of thetampering of materials. This paper mainly researches the blind forensic about the JPEGimage.Firstly, we summarized the digital image passive forensic technology, system structureand classification technology, focus on the present situation and insufficient of the blindforensic about JPEG images. By researching the digital image generation principle, JPEGstandard and image tampered technology, puts up the model of tampered the JPEG image.By the analysis of the frequency characteristics of JPEG blocking artifacts, a method wasput up based on inconsistency of JPEG blocking artifacts to detect composite image. Firstly,calculated the blocking artifacts metrics of each block, we detected and located forgeryregions in terms of the metrics. Experimental results show that our algorithm performs betterthan the traditional algorithm base on the inconsistency of JPEG blocking artifacts in terms ofvarious types of forgery with compositing different image format.By the analysis of quality loss with different quantization matrix in the JPEGcompression, a method was put up based on the quantization characteristic to detectcomposite image. So use the quantization matrix of the background area compresses theimages again and computing the loss of different areas, the tampered areas can bedistinguished from the background according to differences of loss in the recompressed image.Experimental results show that our algorithm can effectively detect various kinds of storageway synthesis image.At last, summarizes the work of the paper, the prospect the blind forensic technologyabout JPEG images research and development.