CN104504644A

CN104504644A - Color image watermark detection method based on invariant-moment geometric correction

Info

Publication number: CN104504644A
Application number: CN201410817024.6A
Authority: CN
Inventors: 杨红颖; 张妍; 牛盼盼
Original assignee: Liaoning Normal University
Current assignee: Liaoning Normal University
Priority date: 2014-12-25
Filing date: 2014-12-25
Publication date: 2015-04-08

Abstract

The invention discloses a color image watermark detection method based on invariant-moment geometric correction. According to the method, in a process of correcting an image containing a watermark, amplitude values of eight low-order quaternion exponential moments of an image to be detected are calculated and are used as training features, and the least square support vector machine theory is combined for training the sample to obtain a training model, so that the geometric correction is carried out, the quaternion exponential moments and the support vector machine theory are combined, a system has the advantages that the digital watermark robustness can be effectively improved, and meanwhile, the watermark information quantity and the imperceptibility of the digital watermark are ensured. In addition, the method has the characteristics of simplicity in calculation and the like, and the practicability of the method for being used for digital image mark copyright protection is enhanced.

Description

Based on the Color digital watermarking detection method of not bending moment geometry correction

Technical field

The invention belongs to Information hiding and digital watermark technology field in multi-media information security, especially one not only has preferably not sentience, and all has the Color digital watermarking detection method based on not bending moment geometry correction of good robustness to normal signal process (medium filtering, edge sharpening, superimposed noise and JPEG compression etc.) and desynchronization attack (rotation, translation, convergent-divergent, shearing, upset etc.).

Background technology

Digital watermarking (Digital Watermarking) is as effective means of supplementing out economy of conventional encryption methods; it is a kind of new technology can protecting copyright and certification source and integrality under open network environment; cause people to pay much attention in recent years, and become a focus of international academic community research.So-called digital figure watermark; the mark (watermark) of certain sense will be had exactly; the method utilizing data to embed is hidden in digital picture product; in order to prove the entitlement of creator to its works; and as qualification, the illegal foundation of encroaching right of prosecution; simultaneously by ensureing the complete reliability of numerical information to the determination and analysis of watermark, thus become intellectual property protection and the false proof effective means of digital multimedia.

So-called desynchronization attack, not refers to that this kind of attack can remove watermark information from containing watermarking images, and refers to that it can destroy synchronous (namely the changing watermark embedment position) of digital watermarking component, thus cause detecting device to can not find effective watermark.In recent years, propose a series of digital image watermark detection method successively, but regrettably, existing digital image watermark detection method is mainly primarily focused in the research of antagonism normal signal process (as lossy compression method, low-pass filtering, noise etc.), and such as rotations, convergent-divergent, translation, ranks are removed, shearing, etc. the opposing effect of geometric attack bad.

Summary of the invention

The present invention is directed to the upper technical matters existing for prior art, there is provided one not only to have preferably not sentience, and to normal signal process (medium filtering, edge sharpening, superimposed noise and JPEG compression etc.) and desynchronization attack (rotation, translation, convergent-divergent, shearing, upset etc.), all there is the Color digital watermarking detection method based on not bending moment geometry correction of good robustness.

Technical solution of the present invention is: a kind of Color digital watermarking detection method based on not bending moment geometry correction, it is characterized in that carrying out as follows:

Step 1: embed watermark in original image;

Step 2: to carrying out X-translation, Y-translation containing watermarking images F, Rotation and Zoom operates, with the image after operating for training image constructs training sample set , , calculate the amplitude of 8 low order hypercomplex number Uniformly bounded of each training image in sample set, obtain 8 proper vectors reflecting corresponding training image feature, use relevant information coefficient , state each training image, obtain training pattern;

Step 3: calculate image to be detected the amplitude of 8 low order hypercomplex number Uniformly bounded, obtain 8 proper vectors reflecting characteristics of image to be detected;

Step 4: utilize training pattern to treat detected image proper vector train, obtain a geometric transformation parameter , utilize this geometric transformation parameter treat detected image and carry out inverse transformation, obtain the image after correcting ;

Step 5: the image after correction middle extraction watermark.

Described step 1 is as follows:

Step 11: carry out quick hypercomplex number Fourier transform to original color image, obtains a real-part matrix and three imaginary-part matrixs;

Step 12: the real part matrix of coefficients being chosen hypercomplex number Fourier transform by key K from mid-frequency region, quantizes with embed watermark image to it;

Step 13: the real part coefficient of amendment symmetric position hypercomplex number Fourier transform, carries out the inverse transformation of hypercomplex number Fourier transform, obtains containing watermark carrier image .

Described step 11 is as follows:

Step 111: by the R of original color image, G, B tri-components carry out Fast Fourier Transform (FFT), use respectively represent;

Step 112: by following formula, namely can obtain 1 real part A and 3 imaginary part C, D, E of coloured image hypercomplex number Fourier transform:

In formula, represent and get plural number real part, represent and get plural number imaginary part, represent real discrete Fourier transformation.

Described step 12 is as follows:

Step 121: to original image icarry out hypercomplex number Fourier transform, obtain a real-part matrix a;

Step 122: selected from mid-frequency region by key K the matrix of coefficients of size ;

Step 123: by revising by the real part coefficient of the hypercomplex number Fourier transform selected, by watermark embedment in view picture coloured image, quantizing process is expressed as follows:

In formula, the real part coefficient of original color image hypercomplex number Fourier transform, the real part coefficient of hypercomplex number Fourier transform after being quantification amendment, represent floor operation, be the bit of watermark, Δ represents watermark embed strength.

The amplitude of 8 low order hypercomplex number Uniformly bounded of each training image in the calculating sample set of described step 2, obtains reflecting that 8 proper vectors of corresponding training image feature are as follows:

Wherein, n is exponent number, and m is multiplicity, be a unit pure quaternion, select at this , represent radial basis function conjugation, and to have

Then, the amplitude of 8 low order hypercomplex number Uniformly bounded is selected

representatively proper vector.

Described step 5 is as follows:

Step 51: to the image after correction carry out quick hypercomplex number Fourier transform, obtain a real-part matrix ;

Step 52: selected from mid-frequency region by key K the matrix of coefficients of size ;

Step 53: by the real part coefficient of hypercomplex number Fourier transform selected, carry out the extraction of watermark, leaching process is expressed as:

Step 54: extract watermark information .

The present invention is in the process corrected containing watermarking images, calculates the amplitude of 8 low order hypercomplex number Uniformly bounded of image to be detected, and makes it as training characteristics, in conjunction with least square method supporting vector machine theory, to sample training, draw training pattern, thus carry out geometry correction.Owing to combining hypercomplex number Uniformly bounded and support vector machine theory; make the present invention effectively can improve Digital Watermark Robustness; ensure that the not sentience of digital watermarking and the quantity of information of watermark simultaneously; this method has and calculates the feature such as simple, enhances its practicality for digital picture Works copyright protection.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the embodiment of the present invention.

Embodiment

As shown in Figure 1, method of the present invention is carried out in accordance with the following steps:

Step 1: embed watermark in original image; Specific as follows:

Step 13: the real part coefficient of amendment symmetric position hypercomplex number Fourier transform, carries out the inverse transformation of hypercomplex number Fourier transform, obtains containing watermark carrier image , specific as follows:

The real part coefficient of amendment symmetric position hypercomplex number Fourier transform, is ensured to remain pure quaternion form through hypercomplex number inverse Fourier transform to spatial domain containing watermarking images, namely still can be transmitted with red, green, blue three look of coloured image;

Step 132: the inverse transformation finally carrying out hypercomplex number Fourier transform can obtain containing watermark carrier image .

Wherein calculate the amplitude of 8 low order hypercomplex number Uniformly bounded of each training image in sample set, obtain reflecting that 8 proper vectors of corresponding training image feature are as follows:

representatively proper vector.

Step 5: the image after correction middle extraction watermark, specific as follows:

Step 54: extract watermark information .

Claims

1., based on a Color digital watermarking detection method for not bending moment geometry correction, it is characterized in that carrying out in accordance with the following steps:

Step 1: embed watermark in original image;

Step 5: the image after correction middle extraction watermark.

2., according to claim 1 based on the Color digital watermarking detection method of not bending moment geometry correction, it is characterized in that described step 1 is as follows:

3., according to claim 2 based on the Color digital watermarking detection method of not bending moment geometry correction, it is characterized in that described step 11 is as follows:

4., according to claim 3 based on the Color digital watermarking detection method of not bending moment geometry correction, it is characterized in that described step 12 is as follows:

5. according to claim 4 based on the Color digital watermarking detection method of not bending moment geometry correction, it is characterized in that the amplitude of 8 low order hypercomplex number Uniformly bounded of each training image in the calculating sample set of described step 2, obtain reflecting that 8 proper vectors of corresponding training image feature are as follows:

representatively proper vector.

6., according to claim 5 based on the Color digital watermarking detection method of not bending moment geometry correction, it is characterized in that described step 5 is as follows:

Step 54: extract watermark information .