Digital Watermarking Techniques for Image Security

In concern to the growth of high-speed computer network and that of the Internet, Digital media offer several advantages over analog media like high quality, easy editing, high fidelity, copying. There are emerged as a protection tool in which data is hidden in an image, audio or video file. Watermark is to hide information in cover image. It is reliable digital image watermarking. It provides high imperceptibility and robustness for copyright protection. Two methods are proposed in this dissertation work, first method is the combination of Discrete Wavelet Transform, Singular Value Decomposition, and Discrete Cosine Transform. It is a robust watermark. In this a multi-channel image watermarking technique is used. It means multiple watermarks are embedded in the image. In this method, initially first level of three watermark images are embedded in the second RGB watermark image and then this second level RGB image watermark is embedded in the RGB cover image to obtain the watermarked image. This process increases the robustness of watermark.