A DCT-based coding of images in watermarking

The recent growth of networked multimedia systems has caused the need for intellectual property rights, like images, music and movies. One approach to solve this problem is to add an invisible image to an image that can be used to provide solid proof of ownership. These invisible images or signatures are known as digital watermarks. In this paper, we describe two techniques for watermarking. A discrete cosine transform algorithm is performed to implement the middle-band embedding for an original image. A differential pulse code modulation method is used to permute a watermark image. The results show that our methods are valid in embedding a watermark in an image, also proves to be effective in decreasing mosquito noise.