Embedding strategy for image watermarking in DCT domain

Where should invisible image watermarks be embedded in the DCT domain in order for the watermarks to be robust? Though many papers in the literature agree that watermarks should be embedded in perceptually significant components, DC components are explicitly excluded from watermark embedding. A new embedding strategy for watermarking is proposed based on a quantitative analysis on magnitude of DCT components. We argue that more robustness can be achieved if watermarks are embedded in DC components since DC components have a much larger perceptual capacity than any AC components. Based on this idea, a watermarking algorithm is presented. We incorporate the feature of texture masking of the human vision system into watermarking. Experimental results demonstrate that the invisible watermarks thus embedded are very robust.