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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 loss of carrier signal quality, the problem of amplitude scaling attack not being well solved, and not being flexible enough.

Inactive Publication Date: 2011-08-24
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
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Effect test

Embodiment 1

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

[0034] 1) From A o The block DCT (DCT: Discrete Cosine Transform) domain extracts the carrier signal x. Put A first 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 between 3 and 64. Arrange all the extracted DCT coefficients into a large sequence as the carrier signal. The extracted carrier signal is shuffled in a random order, and the final carrier signal is generated as x, and its length is N. This step is implemented by the carrier signal extraction device.

[0035] 2) Express the information m to be embedded as a binary sequence b of length p, where each element b j ∈Ω, Ω={0,1}, j=1,...,p. This s...

Embodiment 2

[0079] The difference from Example 1 is that

[0080] 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 this vector is used, denoted as C00, to construct the characteristic sequence s. Specifically, the characteristic sequence s is taken as

[0081] s=C00I N

[0082] 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

[0084] The difference from Example 1 is that

[0085] By removing the components along the watermark embedding direction from the carrier signal, a vector υ that has nothing to do with the watermark embedding process can be obtained. For x j , J=1,..., p, can be determined v j = x j - x j T uu / u T u . This embodiment uses each sub-vector v j The absolute value of the mean value of, constructs the characteristic sequence s. Specifically, the jth subvector s of the feature sequence s j Take as

[0086] 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 characteristic sequence s. Let the function Var{·} denote the variance operator of the vector. Specifically, the jth subvector s of the feature sequence s j Take as

[0087] s j = Var { x j } I L

[0088] In s...

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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 specifically relates to an improved expansion transform dither modulation watermarking method. Background technique [0002] In the past decade, the use and distribution of digital media information has exploded. 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 without copyright. The management and protection of digital content has become an urgent problem 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, and achieve the purpose of verify...

Claims

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Application Information

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