A region-adaptive semi-fragile dual watermarking scheme

Since existing watermarking schemes usually have only a single function, a region-adaptive semi-fragile dual watermarking scheme is proposed, taking into account both watermark embedding capacity and security. The dual watermarks refer to the robust watermark and the fragile watermark. The original image is divided into three regions, i.e., a no watermark region, a fragile watermark region, and a robust watermark region, and, then, the interrelated robust and fragile watermarks are embedded into different regions. The robust and fragile watermarks do not relate to embedding order, and the extracted fragile watermark further strengthens the extracted robust watermark, which makes it more adaptable to the Human Visual System (HVS). Different techniques have been developed to embed different types of watermarks. To increase the embedding capacity and achieve blind extraction, a status code technology was used to embed the robust watermark. To resist the erase attack and achieve blind extraction, a new special bit substitution technology is proposed to embed the fragile watermark. The experimental results show that the proposed dual watermark scheme has higher PSNR, better security, and larger capacity and also achieves the dual functions of copyright protection and integrity verification.