Keyword:
Digital Watermark, Visual Cryptography Copyright Protection, Secret Sharing, Pixel Expansion, Peak Signal-to-Noise Ratio (PSNR), Mean Square of Error (MSE).
Abstract:
This paper proposes a copyright protection scheme for color images and colored watermarks using visual secret sharing based on the concept of visual cryptography. Most watermarking algorithms call for a piece of information to be hidden directly in media content, in such a way that it is imperceptible to a human observer, but detectable by a computer. This paper presents an improved cryptographic watermark method based on Hwang and Naor-Shamir approaches. The technique does not require that the watermark pattern to be embedded in to the original digital image. Verification information is generated and used to validate the ownership of the image. The method is expected to be proved robust for various image processing operations such as filtering, compression, additive noise, and various geometrical attacks such as rotation, scaling, cropping, flipping, and shearing.