Wavelet-based blind watermark retrieval technique

A wavelet-based watermark casting scheme and a blind watermark retrieval technique are investigated in this research. An adaptive watermark hiding method is first developed to determine significant wavelet subbands and to select a couple of significant wavelet coefficients in these subbands automatically. Then, a blind watermark retrieval technique that can detect the embedded watermark in the wavelet domain without the help from the original image is proposed. Experimental results show that the embedded image's watermark can be retrieved successfully without the original image even after the JPEG compression with a quality factor of 20% and the wavelet based (SPIHT) compression attack with the 64:1 compression ratio. With the help of original image, the watermark can be detected after more serious attacks.