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Improved method for expanding and transforming jitter and modulating watermark

A technology of jitter modulation and expansion transformation, applied in image data processing, instrumentation, image data processing, etc., can solve the problems of inflexibility, loss of carrier signal quality, and the problem of amplitude scaling attacks not being well solved.

Inactive Publication Date: 2009-06-10
YANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The performance of this method relies on the human perception model, which is not flexible enough, and the modification of the perception model loses the quality of the carrier signal compared to the case without modification
[0012] In summary, in the known quantitative watermarking technology, the problem of amplitude scaling attack has not been well solved, and several existing methods have corresponding deficiencies

Method used

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  • Improved method for expanding and transforming jitter and modulating watermark
  • Improved method for expanding and transforming jitter and modulating watermark
  • Improved method for expanding and transforming jitter and modulating watermark

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Watermark Carrier A o For an image signal, an improved STDM watermarking method is implemented. The watermark embedding process is as follows: figure 1 shown, including the following steps:

[0034] 1) From A o The block DCT (DCT: Discrete Cosine Transform) domain extracts the carrier signal x. A o Divide into multiple non-overlapping sub-blocks, each block contains 8×8 pixels, and then perform DCT transformation on each block. Perform zigzag sorting on the 64 DCT coefficients in each block, and select 62 DCT coefficients with ordinal numbers ranging from 3 to 64. Arrange all the extracted DCT coefficients into a large sequence as the carrier signal. Then, the extracted carrier signal is scrambled according to a certain random order, and the final carrier signal generated is denoted as x, and its length is N. This step is realized by the carrier signal extraction device.

[0035] 2) Express the information m to be embedded as a binary sequence b of length p, wher...

Embodiment 2

[0078] The difference from Example 1 is that

[0079] In step 5 of the watermark embedding method, the method of calculating the feature sequence s. The DC component of each 8×8 image sub-block constitutes a vector, which has nothing to do with the watermarking process. In this embodiment, the average value of the vector is used, denoted as C00, to construct the feature sequence s. Specifically, the feature sequence s is taken as

[0080] s=C00I N

[0081] At the same time, in step 4 of the watermark detection method, the method of calculating the feature sequence s' is also modified accordingly.

Embodiment 3

[0083] The difference from Example 1 is that

[0084] The component along the watermark embedding direction is eliminated from the carrier signal, and the vector v which has nothing to do with the watermark embedding process can be obtained. for x j , j=1, L, p, can be determined v j = x j - x T j uu / u T u . This embodiment uses each sub-vector v j The absolute value of the mean of constructs the feature sequence s. Specifically, the jth subvector s of the feature sequence s j take as

[0085] In step 5 of the watermark embedding method, the method of calculating the feature sequence s. In this embodiment, the standard deviation of each sub-vector of the carrier signal is used to construct the feature sequence s. Let the function Var{} d...

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Abstract

The invention relates to an improved spread transform dither modulation (STDM) watermarking method and belongs to the technical field of digital watermarks. STDM watermarking has the combined advantages of quantization index modulation watermarking and a spread spectrum communication system, and high large watermark capacity and high robustness and has the disadvantage of high sensitivity to amplitude scaling attack. The invention constructs a signal invariable relative to the scaling for quantification by using a method which comprises: extracting from original content a statistical characteristic sequence which has a characteristic of scaling with original data according to the same scale factor; and obtaining the signal invariable relative to the amplitude scaling by dividing a carrier signal by the introduced characteristic sequence correspondingly. Watermark embedment and detection operation are both carried out on the newly constructed signal. The method improves the robustness of watermarks to amplitude scaling greatly and obtains watermarking performance similar to the original STDM watermarking in other aspects.

Description

technical field [0001] The invention belongs to the technical field of digital watermarking, and in particular relates to an improved extended transformation dithering modulation watermarking method. Background technique [0002] The past decade has seen an explosion in the use and distribution of digital media information. With the help of the Internet, people can easily publish and obtain various digital information, including images, audio, video and text, as well as many online services. But at the same time, piracy has become easier. Unrestricted copying and uncontrollable transmission make digital content copyrightless. The management and protection of digital content has become an urgent problem to be solved in the industry. [0003] Digital watermarking is an emerging copyright protection technology. It studies how to hide a certain amount of additional information in the original data, such as the ownership of the work, the right to use or the company's logo, etc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T1/00G06T9/00
Inventor 朱新山
Owner YANGZHOU UNIV
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