Evaluation of Different Frequency Regions in Multiple Image Watermarking Method

— Due to the development of the internet and mobile technologies in recent years, the protection of the copyright of multimedia documents has become importance. Digital watermarking is the most widely used method for protecting multimedia documents such as digital image and video. In this study, gray-level image watermarking method is proposed using Discrete Cosine Transform, Discrete Wavelet Transform (DWT) and Arnold Transform. In this watermarking method, the watermarks to be embedded are segmented into four equal-sized parts. In order to increase the robustness of watermarking method against the attacks, each one of these parts have been embedded inside different sub-regions of the four separate bands that have been obtained as a result of DWT processing of the cover images. The performance of the proposed gray-level watermarking method for embedding watermarks in different sub regions in DWT frequency domain has been evaluated by applying linear and nonlinear attacks to the watermarked images. Also, in this study the proposed method is compared with the basic low frequency band watermarking method. Experimental results have shown that the proposed method is robust to the attacks. It is also observed that the quality of the watermarked images has been preserved