Screen-shooting watermarking algorithm based on Harris-SIFT feature regions

In recent years, there has been an increasing concern regarding the security and copyright issues associated with images. Unscrupulous individuals exploit electronic images through theft and manipulation, subsequently disseminating them widely, thereby posing significant threats to image copyright ownership and reliability. To address potential screen-shooting attacks on images, this paper proposes a robust watermarking algorithm based on entropy-weighted Harris corner detection and adaptive embedding radius. Firstly, this algorithm uses entropy as the weighted coefficient of Harris corner response values to extract feature points with rich texture features and high robustness. Then, the SIFT algorithm is used to assign orientations to feature points and construct and filter out non-overlapping feature regions. Next, the embedding radius of the watermark is adaptively selected based on the average gray value of the image feature region, and the watermark is embedded into the DFT coefficients of the image feature region. Finally, after completing the watermark embedding in all feature regions, the watermarked image is obtained. In the watermark extraction stage, the captured image is first geometrically distorted and then processed with a Gaussian function before extracting the watermark information from the image. Experimental results show that this algorithm has strong robustness against screen-shooting attacks and common image attacks, while maintaining high transparency.