Digital watermarking using inter-block correlation

In this paper, we propose a new watermark technique which utilizes the inter-block correlation of DCT coefficients. The amount of modification, that is the strength of embedded watermark, depends on the local feature of an image such that the watermark can be strongly embedded in the region where signal distortion is perceptually less visible. This feature also makes difficult for pirate to predict the position in which the watermark signal is embedded, since the amount of modification varies in the image. Embedded watermark can be detected without the parameters used in embedding process nor the original image. The experimental results show that this technique is robust to JPEG compression and Gaussian noise.