Digital Watermark Embedding and Extraction Method Based on Multilevel Wavelet Coefficient Weighting and Quantization

Abstract

The invention provides a digital watermark embedding and extraction method based on multilevel wavelet coefficient weighting and quantization. The proposed method uses the MD5 value of the bunker image and the key given by the user to generate the initial value and parameters of the watermark encryption link and the embedding link, which is used to drive the chaotic map to generate a 2-value pseudo-random matrix to encrypt the 2-value watermark, and the chaotic map The generated intermediate parameters are applied to the coefficient selection of the watermark embedding link, so that the watermark encryption link and the embedding link are tightly coupled with the bunker image and the key given by the user, and the security of the watermark and watermark embedding is improved. The proposed method adopts a weighted embedding strategy of multi-level wavelet coefficients, and the weights are set according to the arithmetic mean of the absolute variation of the wavelet coefficients compressed by JPEG, so that the weights of wavelet coefficients at different levels are different, which reduces the impact of a single wavelet coefficient on watermarking. It further improves the visual quality of the image and the security of the embedded watermark. During watermark extraction, the quality of watermark extraction is improved by filtering out isolated black points, thereby effectively reducing the recovery error of watermark.

Description

technical field [0001] The invention belongs to the cross-research fields of information security and digital image signal processing, and relates to a digital watermark embedding and extraction method, in particular to a digital watermark embedding and extraction method based on multilevel wavelet coefficient weighting and quantization. Background technique [0002] The development of multimedia and network technology enables people to obtain various digital image information more conveniently. Digital images have the advantages of easy storage, easy transmission, and easy operation, but at the same time, pirates can make unauthorized copies and dissemination of them; malicious attackers can easily tamper or forge them, which is easy to cause serious consequences and lead to major economic losses. [0003] For image information security, people have proposed a variety of methods, such as: ① digital image encryption technology that converts plaintext images into ciphertext ...

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Problems solved by technology

[0008] However, the parametric wavelet is used to determine and influence the embedding position of the watermark to improve the security of the watermark embedding strategy. None of the above methods have been analyzed theoretically, and they are only based on experimental examples.

Experiments have shown that the sensitivity of parametric integer wavelet to parameter value changes is difficult to meet the actual needs. When the parameters of parametric wavelet are changed, the embedded watermark can still be approximately extracted, so the security of the embedded watermark is still difficult to guarantee.

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