Watermarking method based on double-threshold correspondence imaging with lossless host image

Abstract A watermarking method based on double-threshold correspondence imaging (DTCI) with lossless host image is proposed, which employ every bit of the 8-bit grayscale host image without changing picture. This image watermarking method firstly processes the host image to obtain symbolic attribute arrays (SAAs). Then the watermark image is performs DTCI operations to rearrange the order of the speckle patterns according to the SAAs. Because there is not any additional information embedded into the host image, it ensures the watermark image with not only complete imperceptibility but also a significant capacity. When the authorized users utilize both the binary numbers of host image and the rearranged speckle patterns as the key, the watermark image can be easily retrieved. Additionally, the suggested method demonstrates remarkable robustness in the face of ‘Salt and Pepper’ noise and cropping attacks.