WATERMARKING METHOD RESISTANT TO GEOMETRIC ATTACK IN WAVELET TRANSFORM DOMAIN

摘要

The present invention relates, in general, to a watermarking method resistant to a geometric attack in a wavelet transform domain, and, more particularly, to technology for embedding a watermark in a discrete wavelet transform (DWT) domain, thus extracting autocorrelation (AC) peaks, which play an important part in the estimation of geometric attacks in ACF-based watermarking, and detecting watermarks using the AC peaks even after geometric distortion is applied. In the watermarking method of the present invention, a watermark pattern is embedded in subbands of a Discrete Wavelet Transform (DWT) domain. An Autocorrelation Function (ACF) of a watermark is executed in the domain, thus detecting a watermark required to estimate a geometric attack. A watermark signal is detected using an undecimated wavelet transform so as to compensate for an image shift in the watermark.