Image digital watermarking algorithm using multiresolution wavelet transform

Watermarking is a technique for labeling digital picture by hiding secret information in the images. This paper presents a method of watermark embedding and extracting based on discrete wavelet transform of blocks and Arnold transform. Different with most previous work, which uses a random number of a sequence of bits as a watermark, the proposed method embeds a watermark with visual recognizable patterns, such as gray image in images. In the proposed method, each pixel of watermark is embedded in the wavelet coefficient of the middle and low frequency of a block in the images. Unlike other watermarking techniques that use a single casting energy, this method casts watermarks in multi-energy level. The performance of the proposed watermarking is robust to variety of signal distortions, such a JPEG, image cropping, sharpening, and blurring attacks.