Wednesday, February 27, 2008

ABSTRACT :

A DIGITAL watermark is a digital signal or pattern inserted into a digital image. Since this signal or pattern is present in each unaltered copy of the original image, the digital watermark may also serve as digital signature for the copies.
Digital watermarking is also to be contrasted with public key encryption, which also transforms original files into another form. Unlike encryption, digital watermarking leaves the original digital data basically intact and recognizable. Digital watermarks are designed to be persistence in viewing, printing or subsequent retransmission or discrimination. Thus, watermarking does not prevent copying but it deters illegal copying by providing a means for establishing the original ownership of a redistributed copy.
Watermarking data for copyright protection is an accepted technique adopted for digital information. This subject has been quite exhaustively researched and several techniques have been established for protecting copyright for still images, audio and video files.
The main aim of this project is to propose a possible new technique for watermarking on images.
Digital Watermarking is a robust and efficient digital image water marking algorithm using the Fast Hadamard Transform is proposed for the copyright protection of digital images. This algorithm can embed or hide an entire image or pattern as a watermark such as a company’s logo or trademark into the original image. The performance of the proposed algorithm is evaluated using the Stirmark, which consists of 90 different types of image attacks. Results show that the proposed algorithm is very robust and can survive most of the stirmark attacks.