Intra-block algorithm for digital watermarking

We present a variant to the DCT-based block algorithm proposed in Hsu and Wu (1996) for signal embedding in digital images. Instead of inter-block relations, our algorithm uses intra-block relations to generate the watermarked image. We describe the algorithm and its performance against translation and cropping. The features of our method are: (1) the watermark is perceptually invisible; (2) little loss of relevant information of original image; (3) the watermark can be retrieved by using a secret key; and (4) the watermark is robust against translation and area cropping.