An Adaptive Middle Frequency Embedded Digital Watermark Algorithm Based on the DCT Domain

This paper presents an algorithm of digital watermark embedding in the middle frequency adaptively based on the DCT domain. According to the energy of the block size after transforming, the algorithm can select the middle frequency coefficient adaptively to do embedding operation. Compared with traditional DCT domain fixed-point algorithm, it reachs a better balance of robust and watermark information hiding. The results show that, particularly in the JPEG compression attack, the algorithm which this paper presents can improve the signal-to-noise and the similarity than the traditional fixed-point algorithm.