A Blind Image Watermarking Algorithm in the Combine Domain

摘要

This paper presents a novel blind digital image watermarking algorithm in the combine domains to resolve the protecting copyright problem. For embedding watermark, the generation principle and distribution features of direct current (DC) coefficient are utilized to directly modify the pixel values in the spatial domain, then 4 different sub-watermarks are embedded into different areas of the host image for four times, respectively. When extracting watermark, the sub-watermark is extracted with blind manner according to DC coefficients of watermarked image and the key-based quantization step, and then the statistical rule and "first to select, second to combine" are proposed to form the final watermark. Hence, the proposed algorithm not only has the simple and quick performance of the spatial domain but also has the high robustness feature of DCT domain. Many experiments have proved the proposed watermarking algorithm has good invisibility of watermark and strong robustness for many added attacks, e.g., JPEG compression, cropping, adding noise, etc. Comparison results also have shown the preponderances of the proposed algorithm.