In this paper, we propose a rotation-invariant image watermarking scheme based on Radon transform. Rotation invariance is achieved using the translation property of the Radon transform. The radon transform emphasize and detect the linear characteristic to calculate the angle of image rotation. The image watermarking scheme used hologram quantization to spread the watermark information and analyses the cover image detail. The watermark is a hologram generated by quantization based on the cover

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... age. The hologram is transformed by a discrete fractional random transform (DFRNT) with a random seed β to make the watermark security. Our method belongs to the blind watermark, because we do not need the original image during detection. The proposed method includes encryption techniques for security, and uses discrete wavelet transform (DWT) domain. DWT domain watermarking is robust to signal processing attacks and watermark synchronization gets rid of the effect of geometric attacks. In rotation attack 0~5 degree, we detect the watermark with 0~0.18% bit error rate (BER). We have performed an intensive simulation to show the robustness of the proposed method.