Research On Adaptive Image Blocks Classification For Image Tamper Detection And Recovery

In recent years,with the rapid development of Internet technology,various kinds of multimedia digital products have sprung up.The multimedia digital product is a double-edged sword,has not only brought us convenience,but also a series of potential information security issues,such as version embezzlement,information tampering.In order to solve these problems,many secure techniques and measures of encryption and digital signature which use special encryption algorithms to protect the target objects are proposed and discussed.Although these methods can ensure the information safety to some degree in the past,the rapid development of computer technology causes old encryption and digital signature to play an increasingly small role in information security protection.For this reason,digital watermarking technology based on tamper detection and recovery has been proposed to solve these problems ensuring Information receiver can receive real information.This technology can actively recover tampered data and have good application value in some fields which need acquiring the original data,such as copyright protection,military,medicine.In this paper,8-bit gray image is taken as the research object,through analyzing the texture feature of image,a watermarking algorithm for image tamper detection and recovery is presented.The main work of this paper is as follows:(1)In order to improve the accuracy of image blocks' feature value and to solve the inadequate concealment of images,an adaptive images block classification algorithm to detect image's tampers and recover with high quality is proposed.First,it divides an image into basic blocks of size 3*3;then distinguishes and marks these basic blocks into smooth blocks and rough blocks,based on the complexity of texture,and feature values can be adaptively generated as recovery information;finally,it cuts off the redundant watermark information and embeds the watermarking by LSB in a single time.This method can obtain relatively accurate result in extracting the image's feature and effectively improve the concealment of carrier image.(2)As for the Eigen value extracted by the existing methods could not flexibly adapt to the change of images textures,leading to low accuracy recovery quality of tampered image,an image blocks classification watermarking method for tamper detection and recovery is proposed.Variance of sub blocks and Canny edge detection algorithm is adopted to group these sub-blocks into smooth blocks,rough blocks and edge blocks.Then,according to sub image's type and recovery threshold,the original information can be generated.Compared with other existing algorithms,this algorithm can extract better quality Eigen value,which further optimizes and effectively improves the recovery quality of the tampered image.