Safe Variable-Capacity Self-Recovery Watermarking Scheme

Since existing watermarking schemes usually cannot recover the tampered position, a safe variable-capacity self-recovery watermarking scheme is proposed. Both watermark embedding capacity and security are taken into account. The original image is divided into texture blocks and smooth blocks, and the texture blocks not only save traditional information, but also save the “details” information. The so-called “details” information refers to the texture information, which not only can effectively resist the mean attack, but also help to improve the quality of the restored image to meet the needs of practical work. And then according to the characteristics of different blocks, the different length compound watermarks are produced. The so-called “compound watermarks” include the authentication watermarks and information watermarks. Authentication watermarks are used to detect the tampered area, and the information watermarks which include basic watermark and additional watermark are used to restore image. Then the compound watermarks are inserted into the other blocks based on the new proposed scheme called three level secret-key embedding scheme (TLSES). And then the tamper blocks are detected and restored by the three level tamper detection scheme (TLTDS). The experimental results show that the scheme can not only accurately detect the tamper region and restore image, but also can effectively resist mean attack and collage attack.