Digital watermarking method based on digital holography and Fourier-Mellin transform

Abstract

The invention discloses a digital watermarking method based on digital holography and Fourier-Mellin transform. The method comprises the following steps that: carrying out conjugate symmetry extension and DFT (Discrete Fourier Transform) to obtain a two-dimensional discrete actual value function F (Mu, v), and mapping the actual value function to 0-255 to generate a digital watermarking hologram; in the intermediate frequency region of carrier image I DFT, embedding the rectangular block of the digital watermarking hologram, and embedding the same rectangular block into the centrosymmetric corresponding block of a magnitude spectrum; and carrying out inverse discrete Fourier transform on the new magnitude spectrum and an original phase spectrum to obtain a watermarking-contained image IW. An embedding method is simplified, embedding quality is improved, and the method achieves good balance between robustness and invisibility.

Description

technical field [0001] The invention belongs to the technical field of digital watermarking, and in particular relates to a digital watermark embedding and extraction method based on digital holography and Fourier Merlin transform against geometric attacks, and is especially suitable for attacks on watermarked images in printing and scanning processes. Background technique [0002] In the field of digital watermarking technology, commonly used attacks include noise, filtering, shearing, scale change, IBM (International business machines) attack, lossy compression coding and geometric attack, where geometric attack includes rotation, scaling and translation transformation of digital images , the direct consequence of these attack methods is to destroy the synchronization between the digital watermark detector and the digital watermark, so that the detector cannot detect the digital watermark signal in the image. However, the common digital image watermarking technology in the...

AI Technical Summary

Problems solved by technology

D. Zheng proposed to embed the watermark in the intermediate frequency region of the image, and gave a phase correlation algorithm for calculating the watermark embedding point to avoid exhaustive search when extracting the watermark, but the Zheng algorithm needs to select the specified embedding point when embedding the watermark , bringing more computation to the embedding process

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