Watermark detection for noisy interpolated images

In this brief, the case where the watermark is detected in a noisy interpolated version of the originally watermarked image is investigated. Polyphase decomposition is utilized at the detection side in order to enable the flexible formation of a fused image, which is appropriate for watermark detection. The optimal fused correlator, obtained by combining information from different image components, is derived through a statistical analysis of the correlation detector properties, followed by Lagrange optimization. It is shown that it is preferable to perform detection in a fused image rather than the original image.