Digital Image Watermarking Against Desynchronization Attacks

1 Digital Image Watermarking Against Desynchronization Attacks M Selin Department of Computer Science,KMEA Engineering College,Edathala Aluva, Kerala ABSTRACT Fast and massive dissemination of image data across the Internet imposes great challenges of protecting images against illegal access and unauthorized reproduction. Image watermarking provides a powerful solution for intellectual protection. This paper presents a new feature-based image watermarking scheme which is robust to desynchronization attacks. The Harris –Laplace detector is used to extract the robust feature points, which can survive various signal processing and affine transformation. A local characteristic region (LCR), is constructed based on the scale-space representation of an image is considered for watermarking. At each LCR, the digital watermark is embedded, by modulating the magnitudes of Discrete Cosine Transform coefficients. The performance of watermark detection is computed based on the correlation coefficient. The correlation coefficient is computed between the embedded watermark bits and the detected bits. The results show that the proposed scheme is invisible and robust against various attacks which include common signals processing and desynchronization attacks.