DWT-based digital image watermarking algorithm

This paper presents a digital watermarking algorithm based on the DWT coefficients. This algorithm does not change any information of the original image, but combines the information of low frequency DWT coefficients and the watermark image. The combination is the key, which is used to extract the watermark. When we need to extract the watermark, we can obtain it by divide the key. Because the algorithm does not change any information of the original image, it will not affect the quality of the original image. Experimental results show that the proposed algorithm is robust and secure against a wide range of image processing operations.