S. Ramakrishnan, T. Gopalakrishnan and K. Balasamy, Dr.Mahalingam College of Engineering and Technology, India

This paper aims at developing a hybrid image watermarking algorithm which satisfies both imperceptibility and robustness requirements. In order to achieve our objectives we have used singular values of Wavelet Transformation’s HL and LH sub bands to embed watermark. Further to increase and control the strength of the watermark, we use a scale factor.An optimal watermark embedding method is developed to achieve minimum watermarking distortion. A secret embedding key is designed to securely embed the fragile watermarks so that the new method is robust to counterfeiting, even when the malicious attackers are fully aware of the watermark embedding algorithm. Experimental results are provided in terms of Peak signal to noise ratio (PSNR), Normalized cross correlation (NCC) and gain factor to demonstrate the effectiveness of the proposed algorithm. Image operations such as JPEG compression from malicious image attacks and, thus, can be used for semi-fragile watermarking.

Watermarking, Wavelet transform, multiscale embedding, Wavelet subspaces.