Blind watermark embedding method and extraction method

Abstract

The invention provides a blind watermark embedding method and extraction method. The embedding method comprises the steps: enabling the positions of all pixels in a watermark drawing board filled witha watermark image to be disordered through a random sorting method to obtain the disordered watermark drawing board, wherein the size of the watermark drawing board is consistent with the pixel sizeof an original image; carrying out the superposing of the disordered watermark drawing board and a spectrum image according to a preset superposition intensity coefficient to obtain a superposed image, wherein the spectrum image is obtained through the two-dimensional DFT (discrete Fourier transform) of the original image; carrying out the inverse two-dimensional DFT of the superposed image to obtain the image with an embedded watermark. The embedding method provided by the invention enables the watermark to be embedded into a frequency domain space of the image, and the low-frequency information has the concealing performances so that the naked eyes cannot see the watermark, thereby reducing the risk that the image is damaged by an image thief, guaranteeing that the quality of the image cannot decrease because of the watermark. The embedding method is higher in anti-attack performance, and can prevent the image zooming, image format changing and image cutting modes.

Description

technical field [0001] The present invention relates to the technical field of image processing, and more specifically, to a blind watermark embedding method and an extraction method. Background technique [0002] With the popularization and development of the Internet, people pay more and more attention to image copyright. Due to the easy theft of images, various anti-theft methods emerge in an endless stream. As the most convenient method to protect image copyright, image watermarking technology has attracted widespread attention. [0003] The common image watermarking method, such as directly printing the copyright trademark on the image, is still easy to be maliciously tampered with, and cannot play a good role in preventing theft. However, the existing invisible watermarking method, namely the blind watermarking method, usually uses the space of the original image Map and print watermarks in different spaces, and then restore the image, such as Arnold transformation, ...

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Problems solved by technology

[0003] The common image watermarking method, such as directly printing the copyright trademark on the image, is still easy to be maliciously tampered with, and cannot play a good role in preventing theft. However, the existing invisible watermarking method, namely the blind watermarking m

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