Digital watermarking using zerotree of DCT

A watermarking technique has been proposed as a method to embed an invisible signal into multimedia data so as to attest the owner identification and discourage the unauthorized copying. In this paper, an efficiently DCT based watermarking technique is proposed. In the proposed method, we take advantage of the zerotree in the rearranged DCT coefficients to embed watermark into image and extract the watermark from the watermarked image more efficiently. The proposed method can directly extract the embedded watermark from the watermarked image without using the original image, so it is feasible to implement it in a real time system. A scheme for spreading the watermarking information is also used to provide the robustness of the digital watermark. The experimental results show that the imperceptibility and robustness of the digital watermark can be guaranteed