Watermark embedding and extracting method based on two-dimensional adaptive Fourier decomposition

Abstract

The invention discloses a watermark embedding and extracting method based on two-dimensional adaptive Fourier decomposition, and relates to the technical field of information security. According to the method, a frequency component of a watermark image is embedded into a source image in a spatial domain, a part of information of the watermark image is converted into a complex form of extraction key with enough complexity for watermark extraction, and the watermark information added into the source image is reduced. Therefore, the processing of color and large-size watermark images can be realized. The anti-attack capability and the anti-interference capability of the watermark image are greatly improved through the extraction key in the complex form. The extracted watermark image is anti-attack and has relatively high quality. According to the method, a self-adaptive Fourier decomposition algorithm is introduced into a watermark technology, and a method combining a spatial domain watermark technology and a frequency domain watermark technology is provided by utilizing the characteristic that different image decomposition expansions are different, so that the actual use requirementsin the field of information encryption and the field of copyright protection can be met.

Description

technical field [0001] The invention relates to the technical field of information security, in particular to a watermark embedding and extraction method based on two-dimensional adaptive Fourier decomposition. Background technique [0002] Digital watermarking technology is an important branch and research direction in the field of information hiding technology. Through digital watermarking technology, the data that needs to be hidden can be embedded into the source image as a watermark image. The embedding of the watermark image does not affect the use of the source image, and authorized Personnel can use the key to extract the embedded watermark image later. At present, digital watermark technology is often used in the field of copyright protection. The existing digital watermarking technology can be mainly divided into spatial domain watermarking technology and frequency domain watermarking technology when embedding watermarked images. The spatial domain watermarking tec...

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Problems solved by technology

[0003] The above-mentioned conventional digital watermarking technology has the ability to completely hide the watermark, prevent tampering and be difficult to be removed by unauthorized personnel, but has the following defects: 1. In the existing digital watermarking technology, in order to reduce the malicious detection Possibilities, complex algorithms are usually used to embed the watermark image, which greatly limits the information capacity of the watermark image itself, so the existing digital watermark technology usually processes watermark images with small information capacity, and the embedded watermark images are usually Small-sized grayscale images or binary images; 2. Although the existing digital watermarking technology can realize the extraction of digital watermarks, the extracted watermarks after processing contain relatively serious noise and poor clarity; 3. The key is usually is a single integer, and because the method of embedding the watermark image into the spectral coefficients of the source image is very complicated and difficult to change, the same algorithm is usua...

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