A DCT domain multipurpose watermarking technique for images

To notify and protect the copyright simultaneously, a visible watermark and an invisible watermark are embedded in different parts of the DCT coefficients of the host image. During the embedding process, the sensitivity of each block to distortion is taken into account based on human visual system (HVS) to preserve the quality of the watermarked image, Experimental results demonstrate that the visible watermark is hard to remove and the invisible watermark is robust to normal signal processing operations.