Watermark embedding method, watermark detecting method and device thereof

Abstract

The invention provides a watermark embedding method, a watermark detecting method and a device thereof. The watermark embedding method comprises the steps of: a step 1: acquiring an original image with size of M0*N0, a first chaotic sequence with length of M0, and a second chaotic sequence with length of N0; a step 2: acquiring a chaotic watermark sequence with length of M0*N0 according to the first chaotic sequence and the second chaotic sequence; step 3: partitioning the original image for acquiring image subblocks, performing discrete cosine DCT transformation on the image subblocks, and embedding the chaotic watermark sequence with length of M0*N0 into image subblocks with frequency coefficient smaller than a first threshold for obtaining a watermark image; and step 4: weighing the watermark image and the original image through a noise sensitivity coefficient, thereby obtaining a final objective image. The watermark embedding method and the device according to the invention have advantages of: high robustness in a watermark-embedded image, high hiding degree and high decryption difficulty.

Description

technical field [0001] The invention relates to the field of image encryption, and in particular provides a watermark embedding and detection method and device. Background technique [0002] The so-called digital image watermark is to add some digital information to the image to achieve the functions of document authenticity identification and copyright protection. The embedded watermark information is hidden in the host file without affecting the observability and integrity of the original file. [0003] A digital watermark can be an author's serial number, a company logo, meaningful text, and more. There are many concepts that are similar or closely related to watermarking. Judging from the current literature, there are already concepts such as Information Hiding, Steganography, Digital Watermarking and Fingerprinting. [0004] In general, digital watermarking should have the following basic features: [0005] (1) Provability: Watermark should be able to provide complet...

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Problems solved by technology

[0006] (2) Unperceivable: Unperceivable includes two meanings, one refers to visual invisibility, that is, the change of the image due to the embedded watermark should be imperceptible to the observer's visual system, the most ideal situation The watermark image is visually identical to the original image, which is the requirement that most watermark algorithms should meet; on the other hand, the watermark cannot be recovered by statistical methods, such as the use of a large number of information products processed by the same watermark. Statistical methods are also unable to extract watermarks or determine the presence of watermarks

[0008] However, once the watermark is decrypted by others, the digital media content can be copied and disseminated at will. This is the problem of over-distribution of digital media content, which has caused huge losses to media content manufacturers, thus restricting the development of digital multimedia applications. , so how to implement effective means of copyright protection and information security in the network environment has become an imminent practical problem

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