Robust optimal image watermarking using graph-based and discrete wavelet transforms, and whale optimization algorithm

As digital content can be copied easily, Copyright infringement has become a concern nowadays. Providing a solution to prevent the abuse of such content is necessary. One of the most common methods to solve this problem is watermarking. In this method, a logo belongs to the owner of the media is embedded in the media. So, the owner can prove the originality or ownership of the media content. Images are one of the most important digital media. Therefore, in this study, a method for digital image watermarking is proposed. The proposed method is based on Graph-based Transform (GBT), Singular Value Decomposition (SVD), and Discrete Wavelet Transform (DWT) which uses a Whale Optimization Algorithm (WOA) to find the best values for the embedding parameters. The cover image is first transformed using the DWT and GBT. Then the watermark logo is embedded onto the singular values of the cover image. The defined objective function for the optimization is based on the parameters PSNR and NC, in the presence of different attacks. Experimental results clearly show a high robustness of the proposed method compared to other similar methods.