A Blind Watermarking Technique Using Difference of Approximation Coefficients in Wavelet Domain

웨이블릿 영역에서 근사 계수의 증감 정보를 이용한 블라인드 워터마크

In this paper, we propose a new blind image watermarking method in wavelet domain. It is necessary to find out watermark insertion location in blind watermark. We use horizontal and vertical difference of LL components to select watermark insertion location, because increment or decrement of successive components is rarely changed in LL band. A pseudo-random sequence is used as a watermark. Experimental results show that the proposed method is robust to various kinds of attacks such as JPEG lossy compression, averaging, median filtering, resizing, histogram equalization, and additive Gaussian noise.