Research On Image Tamper Detection Algorithms Based On JPEG Compression

With the development of the Internet and the popularity of digital cameras,digital images win people's favor for that it can be easily edited,modified and copied.However,the above characteristics of digital images also brings image tampering,they use the illusion of vision to achieve the purpose of malicious communication,which has a negative impact on the community JPEG format is one of the mainstream image compression format.80%of the network image is used JPEG compression standard,so the source image format is often false JPEG.Therefore,the study of the JPEG digital image detection method has important academic and practical.Under such background,this paper realizes the tamper evidence of digital image by detecting the abnormal features such as quadratic compression and blocking effect of the JPEG image.(1)Design a secondary compression detection algorithm based on JPEG Ghost.Under the premise of the image quantization,we detect the quality factor consistence to determine whether the process of secondary image compression.By computing value of gray scale difference and the distribution function,two aspect respectively,could reflect the existence of JPEG Ghost,thus providing the possibility for the secondary compression of the identified image.Considering that when the recompression quality factor is multiplied with the quality factor of the original image,multiple minima may occur to misjudge the original image.Therefore,by calculating the difference pixel values to avoid this problem.Furthermore,we design a two-sample KS statistician to solve the gray-scale difference map which could not fully reflect the secondary compression problem.Experiments show that the algorithm can effectively realize the detection of quadratic compression.(2)A block dislocation detection algorithm based on BAFM is proposed.In order to improve the accuracy of the detection algorithm,the detection algorithm realizes the measurement of the block effect.In this paper,two aspects were considered to verify the algorithm,one is the composite image for the JPEG format,and the other is a composite image for the non-JPEG format.Experiments show that the better the block effect,the higher the accuracy of the measurement,and the faster the execution of the algorithm.The difference between the tamper region and the original region is significant.(3)The JPEG composite image detection system is implemented,which integrates a variety of detection algorithms and it is easy to use and interact,user can submit detection operations at anytime,anywhere,compared to traditional C/S model application,it has obvious advantages and improve the user efficiency to a certain extent.