Robust watermarking algorithm based on JND for screen photographing

Abstract

The invention discloses a robust watermarking algorithm based on JND for screen photographing. The robust watermarking algorithm comprises the steps of watermark embedding area selection and watermark embedding and extraction. In the embedding region selection stage, feature points are found by using a Gaussian function and an intensity-based SIFT algorithm, and a feature region is constructed according to the density of the feature points, so that the feature region is more concentrated on key contents, positioning is more accurate during extraction, and a certain cutting attack can be resisted; in the aspect of watermark embedding, a JND model is used for realizing self-adaptive change of embedding strength along with image brightness and texture, and JPEG compression is considered, so that the strength is still kept in a corresponding relationship after compression, and the balance between robustness and invisibility is achieved; and after the watermark is embedded, the coefficients in the neighborhood are subjected to optimization constraint adjustment to ensure that the coefficients are consistent with the coefficients modified during embedding, and when the watermark is extracted by using statistical features, the number of coefficients with correct size relations is increased to reduce the condition that the extraction results are just opposite, so that the method has higher accuracy.

Description

technical field [0001] The invention relates to a robust digital watermarking technology for screen photography, which is used to protect leaked images caused by screen photography, in particular to a JND-based robust watermarking algorithm for screen photography. Background technique [0002] With the continuous development of information technology and the popularization of smart phones, people can obtain the important information they need by taking pictures of computer screens with their mobile phones. But at the same time, some important information can easily be stored, copied, and transmitted by illegal elements through mobile phones, which will cause the leakage of important information and cause a series of security problems. [0003] Digital watermarking is a common information hiding technology used for copyright protection and leakage tracking. The protection of the picture is achieved by embedding the watermark information into the picture. When a picture is l...

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However, when the extraction fails, the exact opposite of the extraction occurs

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