期刊名称：International Journal of Computer Science Issues
印刷版ISSN：1694-0784
电子版ISSN：1694-0814
出版年度：2011
卷号：8
期号：5
出版社：IJCSI Press
摘要：Digital watermarking algorithms are prune to different attacks. Of these geometric attacks are recognized as one of the strongest attacks for digital watermarking technology. Normalization watermarking algorithm is resistant to geometrical distortions and DC coefficients are perceptually most significant and more robust to many unintentional attacks (signal processing) and intentional attacks (unauthorized removal). In this paper we propose a robust non-blind watermarking algorithm based on DC coefficients and normalization. By applying discrete wavelet transformation technique (DWT) followed by block based Discrete Cosine Transformation (DCT) technique, DC components are obtained. The cover image is normalized using normalization algorithm in different frequency bands using wavelet decomposition and then block based DCT is applied. In the DC coefficients of the sub-band of the image, watermark is embedded. The algorithm resistant to geometrical distortions (rotation, scaling) and different other attacks (histogram equalization, noise) on different contrast images. The quantitative measurements like SNR (Signal to Noise Ratio), MSE (Mean Squared Error), RMSE (Root Mean Squared Error) and PSNR (Peak Signal to Noise Ratio) are tabulated.
