CN103279915B - Based on the figure watermark embedding method of virtual pattern bar code - Google Patents

Abstract

The vector graphics watermark embedding method of virtual pattern bar code, comprises the following steps: (1), definition one comprise the virtual pattern bar code of copyright information; (2), the embedding strategy of virtual pattern bar code watermark unique point; (3), virtual pattern bar code watermark embedding grammar; (4), the detection method of virtual pattern bar code watermark.

Description

Based on the figure watermark embedding method of virtual pattern bar code

Technical field

The invention belongs to graph data copyright protection field, be specifically related to a kind of for based on the figure watermark embedding method of virtual pattern bar code and detection method.

Background technology

Along with the development of computer technology and internet is with universal, and multi-medium data stores and the progress of transmission technology, the transmission of digital product and share and become very easy, also the bootlegging of digital product becomes very easy, bring a series of problem about copyright thereupon.In order to protect the interests of copyright owner, in the urgent need to finding a kind of effective method to protect the intellecture property of digital product.

Vector figure data watermarking algorithm is different from traditional based on watermarking algorithm, this does not mainly have the reasons such as the ubiquity of view data application due to vector figure data, also be that vector figure data is all different with the multi-medium data such as image in data structure, file layout, manifestation mode, applied environment, request for utilization and possible attack etc., general watermarking algorithm is also difficult to directly be applied on vector figure data simultaneously.As can be seen here, the application of data watermark technology on vector figure data has more potential purposes.In fact, as a kind of important form of multimedia messages, the Copyright Protection of graph data is also a very important problem.Along with the growing of computer aided design/computer aided machine technology (CAD/CAM) with apply widely gradually, security and the intellectual property protection problem of various drawing, 3D model start attention.In addition, also have various figure and animation etc., these all belong to graph data.In recent years, the digital watermark technology of graph data starts to be paid attention to gradually.

Summary of the invention

In order to overcome easily being illegally duplicated of existing map vector data, be cracked the deficiency with raw data Distortionless by reverse, the invention provides and to be a kind ofly illegally duplicated effectively to solve vector figure data, to be cracked and the vector graphics watermark embedding method based on virtual pattern bar code of raw data Distortionless problem and detection method by reverse.

The technical solution adopted for the present invention to solve the technical problems is:

A vector graphics watermark embedding method for virtual pattern bar code, described vector graphics watermark embedding method comprises the following steps:

(1), the virtual pattern bar code that comprises copyright information is defined

(1.1), the copyright information after encryption is modulated in virtual pattern bar code.

(1.2), with the reference direction of map direct north for virtual pattern bar code, according to user's particular demands virtual pattern bar code rotation alpha (0≤α≤360) degree, virtual pattern bar code is detected to prevent disabled user;

(1.3) each the spacing λ (0≤λ), in virtual pattern bar code, illustrates the copyright information of encryption;

(1.4) if virtual pattern bar code is greater than vector figure data scope, just scaled virtual pattern bar code;

(1.5) if virtual pattern bar code is less than vector figure data scope, just virtual pattern bar code is repeated, until cover vector figure data scope;

(1.6), in order to strengthen the robustness of figure watermark, the virtual pattern bar code of multiple directions can be increased, guaranteeing that virtual pattern bar code can be properly detected;

(2), the embedding strategy of virtual pattern bar code watermark unique point

(2.1), when virtual pattern bar code line crossing with vector graphics coordinate sequence, and when intersection point overlaps with the end points of line segment, so just do not need to do any process, directly use end points;

(2.2), when virtual pattern bar code line crossing with vector graphics coordinate sequence, but the distance between intersection point and end points be less than one limit error amount d time, just delete originally nearest end points, replace end points with new intersection point;

(2.3), when virtual pattern bar code line and vector graphics coordinate sequence properly intersect, the not above two kinds of special circumstances of the intersection point formed, adopt intersection point to move left and right an error amount d limited along mesh lines, so in these two points, select one of them point to insert coordinate string;

(3), virtual pattern bar code watermark embedding grammar

Whether have intersection point to each straight-line detection in vector graphics coordinate sequence and virtual pattern bar code straight line, if there is intersection point, so just according to unique point embedding strategy, relevant intersection is inserted in coordinate sequence, concrete grammar step is as follows:

(3.1) reference direction of vector graphics, is determined;

(3.2), to the adjacent two point (X in vector graphics coordinate sequence data ₁, Y ₁) and (X ₂, Y ₂), judge virtual pattern bar code straight line Y=kX+b and line segment (X ₁, Y ₁)-(X ₂, Y ₂) between whether have intersection point, (X ₁, Y ₁) and (X ₂, Y ₂) substitute into virtual pattern bar code straight line Y=KX+B respectively and obtain discriminant (Y ₁-kX ₁-b) and (Y ₂-kX ₂-b), then judge intersection point situation according to these two discriminants.

(3.3), as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) > 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in virtual pattern bar code straight line the same side, therefore can not intersection point be there is.

(3.4), when $\left\{\begin{array}{c}{Y}_1=k{X}_1+b\\ Y_2={\mathrm{kX}}_2+b\end{array}\right.$ Set up simultaneously, then line segment (X is described ₁, Y ₁)-(X ₂, Y ₂) overlapped with virtual pattern bar code straight line Y=K × X+B, have numerous intersection point, that therefore abandons this line segment asks friendship;

(3.5), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂).

(3.6), as (Y ₁-kX ₂-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁).

(3.7), as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) < 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in the both sides of virtual pattern bar code straight line, there is virtual pattern bar code unique point.

(3.8) if there is intersection point, then set intersection point as (X, Y), so it must be (X ₁, Y ₁)-(X ₂, Y ₂) on line segment a bit, its (X, Y) coordinate can by (X ₁, Y ₁)-(X ₂, Y ₂) 2 determine:

$\left\{\begin{array}{c}X=\frac{X_1+{\mathrm{\&mu;X}}_2}{1+\mathrm{\&mu;}}\\ Y-\frac{Y_1+{\mathrm{\&mu;Y}}_2}{1+\mathrm{\&mu;}}\end{array}\right.---\left(1\right)$

The intersection point (X, Y) that formula (1) is determined is substituted into known straight-line equation Y=K × X+B and tries to achieve μ:

$\mathrm{\&mu;}=-\frac{(Y_1{-\mathrm{kX}}_1-b)}{(Y_2-k{X}_2-b)}---\left(2\right)$

Again the μ tried to achieve by (2) is substituted into (1) formula, the coordinate figure of (X, Y) coordinate can be tried to achieve.

(3.9) (the X in coordinate sequence is inserted into after, (X, Y) coordinate being adjusted by watermark feature point embedding strategy ₁, Y ₁) and (X ₂, Y ₂) between, thus realize virtual pattern bar code watermark and be embedded in vector graphics.

(4), the detection method of virtual pattern bar code watermark

The detection of virtual pattern bar code watermark is the inverse process of its embedding grammar, and concrete grammar step is as follows:

(4.1), calibration vector graph data reference direction;

(4.2), tablet pattern watermark parameters from virtual pattern barcode configuration file;

(4.3), (3.2) are performed---(3.8) detect virtual pattern bar code watermark unique point.

(4.4), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter S _watermark++.

(4.5), as (Y ₁-kX ₁-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter S _watermark++.

(4.6), in addition, be all non-embedded watermark feature point, noise characteristic point counter S _noise++.

(4.7), all the watermark feature point detection of virtual pattern bar code straight line is complete, calculates value, if then think to there is virtual pattern bar code watermark mark.

(4.8), according to the S detected _watermarkfigure watermark feature point, identifies in vector figure data, and carries out the error correction of virtual pattern bar code, and then indicates virtual pattern bar code watermark characteristic pattern by the form of figure.

(4.9), extract virtual pattern bar code, explain the information in virtual pattern bar code.

(4.10), the encryption copyright information obtained be decrypted process, obtain copyright information.

The technology of the present invention core concept is on the basis analyzing vector graphics feature, according to the geometrical constraint characteristic of virtual pattern bar code, and virtual pattern bar code has natural self-correction and anti-shear performance, propose a kind of vector graphics watermarking algorithm based on virtual pattern bar code, comprising: the embedding grammar of watermark and detection method.

Advantage of the present invention is: solve current vector graphics watermarking algorithm to the dependence of coordinate data sequential organization form, solves the Attack Digital Watermarking problems such as the watermark location of vector graphics, shearing and abbreviation, drastically increases the robustness of watermark; By designing a specific virtual pattern bar code as watermark identifier, representing watermark information with virtual bar code, achieving low capacity embedding data and representing the large content problems of watermark; Algorithm is controlled to the trueness error that vector figure data causes, and watermark can accurately be extracted.The present invention can provide effective copyright protection for the propagation of vector figure data and application.

Accompanying drawing explanation

Fig. 1 is the vector graphics watermark embedment process flow diagram based on virtual pattern bar code

Fig. 2 is the virtual pattern bar code mark that modulation has encryption copyright information.

Fig. 3 Fig. 4 Fig. 5 be virtual pattern bar code embed figure watermark feature point solve schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

With reference to Fig. 2 ~ Fig. 5, a kind of vector graphics watermark embedding method of virtual pattern bar code, described vector graphics watermark embedding method comprises the following steps:

(1), Fig. 2 defines the virtual pattern bar code that comprises copyright information

(1.1), the copyright information after encryption is modulated in virtual pattern bar code.

(1.2), with the reference direction of map direct north for virtual pattern bar code, according to user's particular demands virtual pattern bar code rotation alpha (0≤α≤360) degree, virtual pattern bar code is detected to prevent disabled user;

(1.3) each the spacing λ (0≤λ), in virtual pattern bar code, illustrates the copyright information of encryption;

(1.4) if virtual pattern bar code is greater than vector figure data scope, just scaled virtual pattern bar code;

(1.5) if virtual pattern bar code is less than vector figure data scope, just virtual pattern bar code is repeated, until cover vector figure data scope;

(1.6), in order to strengthen the robustness of figure watermark, the virtual pattern bar code of multiple directions can be increased, guaranteeing that virtual pattern bar code can be properly detected;

(2), the embedding strategy of virtual pattern bar code watermark unique point

(2.1), when virtual pattern bar code line crossing with vector graphics coordinate sequence, and when intersection point overlaps with the end points of line segment, so just do not need to do any process, directly use end points;

(2.2), when virtual pattern bar code line crossing with vector graphics coordinate sequence, but the distance between intersection point and end points be less than one limit error amount d time, just delete originally nearest end points, replace end points with new intersection point;

(2.3), when virtual pattern bar code line and vector graphics coordinate sequence properly intersect, the not above two kinds of special circumstances of the intersection point formed, adopt intersection point to move left and right an error amount d limited along mesh lines, so in these two points, select one of them point to insert coordinate string;

(3), virtual pattern bar code watermark embedding grammar

Whether have intersection point to each straight-line detection in vector graphics coordinate sequence and virtual pattern bar code straight line, if there is intersection point, so just according to unique point embedding strategy, relevant intersection is inserted in coordinate sequence, concrete grammar step is as follows:

(3.1) reference direction of vector graphics, is determined;

(3.2), to the adjacent two point (X in vector graphics coordinate sequence data ₁, Y ₁) and (X ₂, Y ₂), judge virtual pattern bar code straight line Y=kX+b and line segment (X ₁, Y ₁)-(X ₂, Y ₂) between whether have intersection point, (X ₁, Y ₁) and (X ₂, Y ₂) substitute into virtual pattern bar code straight line Y=KX+B respectively and obtain discriminant (Y ₁-kX ₁-b) and (Y ₂-kX ₂-b), then judge intersection point situation according to these two discriminants.

(3.3), Fig. 3 Fig. 4 illustrates: as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) > 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in virtual pattern bar code straight line the same side, therefore can not intersection point be there is.

(3.4), when $\left\{\begin{array}{c}{Y}_1=k{X}_1+b\\ Y_2={\mathrm{kX}}_2+b\end{array}\right.$ Set up simultaneously, then line segment (X is described ₁, Y ₁)-(X ₂, Y ₂) overlapped with virtual pattern bar code straight line Y=K × X+B, have numerous intersection point, that therefore abandons this line segment asks friendship;

(3.5), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂).

(3.6), as (Y ₁-kX ₁-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁).

(3.7), Fig. 5 illustrates: as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) < 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in the both sides of virtual pattern bar code straight line, there is virtual pattern bar code unique point.

(3.8) if there is intersection point, then set intersection point as (X, Y), so it must be (X ₁, Y ₁)-(X ₂, Y ₂) on line segment a bit, its (X, Y) coordinate can by (X ₁, Y ₁)-(X ₂, Y ₂) 2 determine:

$\left\{\begin{array}{c}X=\frac{X_1+{\mathrm{\&mu;X}}_2}{1+\mathrm{\&mu;}}\\ Y-\frac{Y_1+{\mathrm{\&mu;Y}}_2}{1+\mathrm{\&mu;}}\end{array}\right.---\left(1\right)$

The intersection point (X, Y) that formula (1) is determined is substituted into known straight-line equation Y=K × X+B and tries to achieve μ:

$\mathrm{\&mu;}=-\frac{(Y_1{-\mathrm{kX}}_1-b)}{(Y_2-k{X}_2-b)}---\left(2\right)$

Again the μ tried to achieve by (2) is substituted into (1) formula, the coordinate figure of (X, Y) coordinate can be tried to achieve.

(3.9) (the X in coordinate sequence is inserted into after, (X, Y) coordinate being adjusted by watermark feature point embedding strategy ₁, Y ₁) and (X ₂, Y ₂) between, thus realize virtual pattern bar code watermark and be embedded in vector graphics.

(4), the detection method of virtual pattern bar code watermark

The detection of virtual pattern bar code watermark is the inverse process of its embedding grammar, and concrete grammar step is as follows:

(4.1), calibration vector graph data reference direction;

(4.2), tablet pattern watermark parameters from virtual pattern barcode configuration file;

(4.3), (3.2) are performed---(3.8) detect virtual pattern bar code watermark unique point.

(4.4), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter s _watermark++.

(4.5), as (Y ₁-kX ₁-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter S _watermark++.

(4.6), in addition, be all non-embedded watermark feature point, noise characteristic point counter S _noise++.

(4.7), all the watermark feature point detection of virtual pattern bar code straight line is complete, calculates value, if then think to there is virtual pattern bar code watermark mark.

(4.8), according to the S detected _watermarkfigure watermark feature point, identifies in vector figure data, and carries out the error correction of virtual pattern bar code, and then indicates virtual pattern bar code watermark characteristic pattern by the form of figure.

(4.9), extract virtual pattern bar code, explain the information in virtual pattern bar code.

(4.10), the encryption copyright information obtained be decrypted process, obtain copyright information.

Claims (1)

1. the vector graphics watermark embedding method of virtual pattern bar code, described vector graphics watermark embedding method comprises the following steps:

(1), the virtual pattern bar code that comprises copyright information is defined

(1.1), the copyright information after encryption is modulated in virtual pattern bar code;

(1.2), with the reference direction of map direct north for virtual pattern bar code, according to user's particular demands virtual pattern bar code rotation alpha degree, 0≤α≤360, detect virtual pattern bar code to prevent disabled user;

(1.3) each the spacing λ, in virtual pattern bar code, 0≤λ, illustrates the copyright information of encryption;

(1.4) if virtual pattern bar code is greater than vector figure data scope, just scaled virtual pattern bar code;

(1.5) if virtual pattern bar code is less than vector figure data scope, just virtual pattern bar code is repeated, until cover vector figure data scope;

(1.6), in order to strengthen the robustness of figure watermark, by increasing the virtual pattern bar code of multiple directions, guarantee that virtual pattern bar code can be properly detected;

(2), the embedding strategy of virtual pattern bar code watermark unique point

(2.1), when virtual pattern bar code line crossing with vector graphics coordinate sequence, and when intersection point overlaps with the end points of line segment, so just do not need to do any process, directly use end points;

(2.2), when virtual pattern bar code line crossing with vector graphics coordinate sequence, but the distance between intersection point and end points be less than one limit error amount d time, just delete originally nearest end points, replace end points with new intersection point;

(2.3), when virtual pattern bar code line and vector graphics coordinate sequence properly intersect, the not above two kinds of special circumstances of the intersection point formed, intersection point is adopted to move left and right an error amount d limited along virtual pattern bar code line, so about this in two points, one of them point is selected to insert coordinate string;

(3), virtual pattern bar code watermark embedding grammar

Whether have intersection point to each straight-line detection in vector graphics coordinate sequence and virtual pattern bar code straight line, if there is intersection point, so just according to unique point embedding strategy, relevant intersection is inserted in coordinate sequence, concrete grammar step is as follows:

(3.1) reference direction of vector graphics, is determined;

(3.2), to the adjacent two point (X in vector graphics coordinate sequence data ₁, Y ₁) and (X ₂, Y ₂), judge virtual pattern bar code straight line Y=kX+b and line segment (X ₁, Y ₁)-(X ₂, Y ₂) between whether have intersection point, (X ₁, Y ₁) and (X ₂, Y ₂) substitute into virtual pattern bar code straight line Y=kX+b respectively and obtain discriminant (Y ₁-kX ₁-b) and (Y ₂-kX ₂-b), then judge intersection point situation according to these two discriminants;

(3.3), as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) > 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in virtual pattern bar code straight line the same side, therefore can not intersection point be there is;

(3.4), when set up simultaneously, then line segment (X is described ₁, Y ₁)-(X ₂, Y ₂) overlapped with virtual pattern bar code straight line Y=kX+b, have numerous intersection point, that therefore abandons this line segment asks friendship;

(3.5), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂);

(3.6), as (Y ₁-kX ₁-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁);

(3.7), as (Y ₂-kX ₂-b) × (Y ₁-kX ₁-b) < 0, then (X is described ₁, Y ₁) and (X ₂, Y ₂) in the both sides of virtual pattern bar code straight line, there is virtual pattern bar code unique point;

(3.8) if there is intersection point, then set intersection point as (X, Y), so it must be (X ₁, Y ₁)-(X ₂, Y ₂) on line segment a bit, its (X, Y) coordinate can by (X ₁, Y ₁)-(X ₂, Y ₂) 2 determine:

The intersection point (X, Y) that formula (1) is determined is substituted into known straight-line equation Y=kX+b and tries to achieve μ:

Again the μ tried to achieve by formula (2) is substituted into formula (1) formula, the coordinate figure of (X, Y) coordinate can be tried to achieve;

(3.9) (the X in coordinate sequence is inserted into after, (X, Y) coordinate being adjusted by watermark feature point embedding strategy ₁, Y ₁) and (X ₂, Y ₂) between, thus realize virtual pattern bar code watermark and be embedded in vector graphics;

(4), the detection method of virtual pattern bar code watermark

The detection of virtual pattern bar code watermark is the inverse process of its embedding grammar, and concrete grammar step is as follows:

(4.1), calibration vector graph data reference direction;

(4.2), tablet pattern watermark parameters from virtual pattern barcode configuration file;

(4.3), (3.2) are performed---(3.8) detect virtual pattern bar code watermark unique point;

(4.4), as (Y ₂-kX ₂-b)=0, then (X is described ₂, Y ₂) with virtual pattern bar code straight line intersection in (X ₂, Y ₂), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter S _watermarkincrease counting;

(4.5), as (Y ₁-kX ₁-b)=0, then (X is described ₁, Y ₁) with virtual pattern bar code straight line intersection in (X ₁, Y ₁), this unique point is the virtual pattern bar code watermark unique point embedded, watermark feature point counter S _watermarkincrease counting;

(4.6), except the watermark feature point in (4.4) and (4.5), be all non-embedded watermark feature point, noise characteristic point counter S _noiseincrease counting;

(4.7), all the watermark feature point detection of virtual pattern bar code straight line is complete, calculates value, if then think to there is virtual pattern bar code watermark mark;

(4.8), according to the S detected _watermarkfigure watermark feature point, identifies in vector figure data, and carries out the error correction of virtual pattern bar code, and then indicates virtual pattern bar code watermark characteristic pattern by the form of figure;

(4.9), extract virtual pattern bar code, explain the information in virtual pattern bar code;

(4.10), the encryption copyright information obtained be decrypted process, obtain copyright information.