Digital watermarking using Walsh code sequences with error spreading technique and intra-pixel prediction
Digital watermarking is one solution to protect intellectual properties and copyright by hiding information, such as a random sequence or a logo, into digital media. In this paper, a new watermarking scheme is proposed. A real logo is embedded into the media with a set of Walsh code sequences (WCSs) and some error spreading techniques, such as interleaving. The logo can be extracted from a possibly corrupted image, without the help of the original uncorrupted image. The extracted logo is then corrected by intra-pixel prediction (IPP) and becomes more "readable and noticeable". The major advantage of hiding a real logo is that the logo may still be readable by human eyes even though the watermarked image is corrupted. Also, the extracted logo can be corrected by using the characteristics of images.