CN108717682A - A kind of hiding and extracting method for the anti-counterfeiting information that mother matrix screen angle is 0 degree - Google Patents
A kind of hiding and extracting method for the anti-counterfeiting information that mother matrix screen angle is 0 degree Download PDFInfo
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- CN108717682A CN108717682A CN201810516536.7A CN201810516536A CN108717682A CN 108717682 A CN108717682 A CN 108717682A CN 201810516536 A CN201810516536 A CN 201810516536A CN 108717682 A CN108717682 A CN 108717682A
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- counterfeiting information
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T1/00—General purpose image data processing
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T9/00—Image coding
Abstract
The invention discloses a kind of hiding and extracting methods for the anti-counterfeiting information that mother matrix screen angle is 0 degree, include the following steps：Step 1: setting host image and determining hidden area；Step 2: host image halftone process；Step 3: anti-counterfeiting information is hidden；Step 4: the identification of anti-counterfeiting information.The position of phase-modulation of the present invention is more various more flexible, and recognition methods is more scientific, the concealment higher of anti-counterfeiting information.
Description
Technical field
The invention belongs to grating field of anti-counterfeit technology, and in particular to the anti-counterfeiting information that a kind of mother matrix screen angle is 0 degree
Hiding and extracting method.
Background technology
The limit resolution capability of human eye normal vision is limited, the size of dot of image after digital screening and site
When being smaller than the limit resolution capability of human eye vision, human eye cannot distinguish site.So the actually binary map of discretization
It is discontinuous when picture, but due to human-eye visual characteristic, gone if seeing with certain viewing distance, cannot distinguish between site at all,
Image detail is namely cannot distinguish between, finally gives people a kind of image effect continuously adjusted, to realize the printing of continuous tone
It replicates.
It is anti-counterfeiting technology that halftone screen technology and Moire effect are combined generation that grating is anti-fake, by half tone image
As soon as several rows of site regards the straight line of rule black as, then energy after the digital raster of itself and same period and width is overlapped
Longitudinal Moire fringe of period infinity is formed, digital raster is exactly to simulate black-white grating optical characteristics on computers and design
A kind of digital raster.Black-white grating is made of largely very subtle chequered with black and white parallel stripes.Ideal situation
Lower black streaking should ensure that completely opaque, that is, light transmittance is zero, informal voucher line i.e. slit, light transmittance 100%.
Most common phase modulation during grating is anti-fake is completed by the position of changing section site, all quilts
Site after movement integrally constitutes new hiding information pattern, is that a kind of that embedded anti-counterfeiting information will be needed to be hidden will be hidden
Algorithm is hidden, it is whole after carrying out am screening processing to halftoning host's figure due to this low-frequency filter characteristics of human eye vision
The part dot location of structural reform change regional area is that will not significantly cause people behind its micro position since site is very small
Eye is to feel perception, among hiding information is embedded into host image based on this principle, and will not cause the sense of human eye vision
Know；Then corresponding grating is utilized, can just be shown when to steganographic detection all by the entire hiding of mobile site composition
Information.
The algorithmic formula of phase modulation is：Wherein, X and Y indicate respectively site laterally and
Longitudinal displacement, D represent the distance between two sites, i.e., the practical distance moved in site is D/2, and mobile direction is
Screen angle direction, unit mm, since screen frequency certainly will be arranged in image halftoning process, D is known to one
Numerical value,
Although phase modulation, using very universal, there is also following deficiencies：
(1), the stage is hidden in anti-counterfeiting information, when dot percentage is more than 20%, net will produce using phase modulation
Point overlap joint problem, causes visual perception, concealment relatively low；
(2), site shift position is limited.
Invention content
The object of the present invention is to provide a kind of hiding and extracting method for the anti-counterfeiting information that mother matrix screen angle is 0 degree, phases
The position of position modulation is more various more flexible, and recognition methods is more scientific, the concealment higher of anti-counterfeiting information.
The present invention provides the following technical solutions：It the anti-counterfeiting information that a kind of mother matrix screen angle is 0 degree hiding and carries
Method is taken, is included the following steps：
Step 1: setting host image and determining hidden area
Host image is set, host image is the digital document being made of m*n pixel, and has 4 Color Channels,
Color Channel is made of C-channel, the channels M, the channels Y and K channel；
There is the hidden area that anti-counterfeiting information can be arranged, hidden area to have s*s at least one channel of host image
A pixel, s are respectively less than m and n, and the channel where hidden area is mother matrix, and remaining channel is 3 secondary versions, is determined on mother matrix
The position of hidden area remembers that color value of all pixels point of hidden area on mother matrix is identical, is denoted as α, ranging from the 0.1 of α
~0.5；
Step 2: host image halftone process
Screening parameter is respectively set to 4 channels and carries out screening processing, screening processing adjusts screen, screening parameter packet using half
Output resolution ratio, screen frequency, dot shape and screen angle are included, when carrying out screening processing respectively to 4 channels, use is identical
Output resolution ratio, screen frequency and dot shape, dot shape is circle, and the screen angle of mother matrix is 0 °, is obtained by net
The mother matrix half-tone picture and 3 width pair version half-tone pictures of point composition；
Step 3: anti-counterfeiting information is hidden
It chooses and needs hiding anti-counterfeiting information, mother matrix half-tone picture is opened in image processing software, according to anti-counterfeiting information
Profile establish site constituency in corresponding hidden area, remember that the site in the constituency of site is set A, by the site of set A
Carry out phase-modulation；
The method for building up in site constituency is：
(1), in photoshop softwares, new image one, the length and width of image one are identical with the length and width of host image, figure
The input resolution ratio of picture one is identical with the output resolution ratio, and background content is white, and " figure layer 0 " is obtained in figure layer channel,
The mother matrix half-tone picture is copied into image one, is obtained " figure layer 1 ", replicates " figure layer 1 ", obtains " figure layer 2 "；By " figure layer 2 ",
" figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window；
(2), " figure layer 3 " is created, " figure layer 3 ", " figure layer 2 ", " figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window
In, it is placed in anti-counterfeiting information in " figure layer 3 ", anti-counterfeiting information is moved to the corresponding position of hidden area, " figure layer 3 " is chosen, makes
Anti-counterfeiting information is chosen with magic wand menu, obtains site constituency, setting " figure layer 3 " is invisible；
The method of phase-modulation is：Move identical angle and distance, any in note set A in all sites of set A
Site a establishes polar coordinates by pole of the central point q of site a, and the position that site a moves rear center's point is q ', the pole of q '
Coordinate is (ρ, γ), and q ' is any point on polar equation ρ, and the value of ρ is the distance of site a movements, and γ moves for site a
Rear central point and it is mobile before central point line and horizontal line between angle, remember that the screen frequency is l, polar coordinates side
Journey ρ is：
After the completion of phase-modulation, obtain the mother matrix half-tone picture for carrying anti-counterfeiting information, by its with 3 width pair version half-tone pictures into
Row image synthesizes, and obtains the host image half-tone picture for carrying anti-counterfeiting information；
Step 4: the identification of anti-counterfeiting information
Make identification grating：The identification grating for preparing digital document form identifies that the area of grating is more than hidden area
Area, identification grating is mutually parallel to be alternatively arranged by the identical blackstreak of length and transparent stripe to be formed, the width of blackstreak
Degree is T1, the width of transparent stripe is T2, wherein
Identify anti-counterfeiting information：It will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation is known
Other grating so that the angle between identification grating and horizontal line is β, is then moved forward and backward identification grating along the directions β, until set
The site of A forms the anti-counterfeiting information with powerful contrast with identification grating, and to complete the identification of anti-counterfeiting information, angle β is really
The method of determining is：
In the step 4, the determination method of angle β is：
WhenWhen, β=0 °；
WhenWhen, β=90 °.
As further describing for above-mentioned technical proposal：
In the step 2, host image halftone process is completed in photoshop softwares, is beaten in photoshop
Host image is opened, the screening processing adjusts screen using half in photoshop；
Each the method for channel progress screening processing is：Channel is chosen, channel is converted into bitmap, when conversion described in setting
Then output resolution ratio adjusts screen to the processing of channel screening using half, the screen frequency is 90~200lpi.
As further describing for above-mentioned technical proposal：
The arbitrary combination that the screen angle of described 3 secondary versions is 15 °, 45 ° and 75 °.
As further describing for above-mentioned technical proposal：
The arbitrary combination that the screen angle of described 3 secondary versions is 18.44 °, 45 ° and 71.57 °.
As further describing for above-mentioned technical proposal：
Further include that will be embedded with the host image half-tone picture the output for printing for carrying anti-counterfeiting information in the step 3, print
Before brushing output, the setting identification label on host image half-tone picture identifies and is labeled as decussate texture, the one of decussate texture
Angle between side and horizontal line is β, and then control exposure output by output equipment is made film at printing plate, or correspondence
Seal carving version is shone again, and the host image for obtaining carrying anti-counterfeiting information is in kind；
Further include that the identification grating of digital document form is prepared into corresponding grating in kind in the step 4, it will be real
Object light grid are covered on host image material object, and rotation grating in kind is marked according to identification so that the blackstreak of grating in kind or
Person's transparent stripe and horizontal angle are β, are then moved forward and backward grating in kind along the directions β, until observe anti-counterfeiting information, it is complete
At identification.
As further describing for above-mentioned technical proposal：
In the step 3, image synthetic method is：
New image two in photoshop, the length and width of image two are identical with the length and width of host image, the input of image two
Resolution ratio is identical with the output resolution ratio, and background content is white, and color mode is CMKY patterns, by the mother matrix halftoning
Figure and 3 width pair version half-tone pictures be copied into corresponding Color Channel to get.
As further describing for above-mentioned technical proposal：
The output resolution ratio is the integral multiple of screen frequency.
As further describing for above-mentioned technical proposal：
The output resolution ratio is 2400dpi, screen frequency 96lpi.
As further describing for above-mentioned technical proposal：
The output resolution ratio is 1440dpi, screen frequency 96lpi.
As further describing for above-mentioned technical proposal：
The output resolution ratio is 1920dpi, screen frequency 96lpi.
Beneficial effects of the present invention：The position of phase-modulation is more various more flexible, and recognition methods is more scientific, anti-counterfeiting information
Concealment higher, it is specific as follows：
1, step one of the invention, it may be determined that color value of the hidden area on Color Channel, in halftone process,
Color value α corresponds to the dot percentage of site, indirectly determines the distance of site displacement in phase modulation process, step
One determines the data such as the color mode of host image and image size, further defines the specific location of mother matrix, hidden area,
Host image is opened in photoshop, observation colouring information finds corresponding hidden area, easy to operate；Host image can be with
It is the original copy directly made in image processing software, can also be the qualified original copy randomly selected, the scope of application is more
Extensively, more flexible；
2, step 1 of the present invention, α only consider that 0.1~0.5 range is surveyed because in practical operation by many experiments
Examination finds that when dot percentage is less than 0.1, the concealment of anti-counterfeiting information is very good, but it is very poor to extract recognition performance；Work as net
When point percentage is more than 0.5, the extraction recognition performance of anti-counterfeiting information is preferable, but concealment is weaker, best hidden to reach
Property and extractability, in addition, in practical operation, when dot percentage reaches 0.5, using the halftoning after photoshop screenings
In figure (dot shape is circle), two neighboring site has contacted with each other the case where not generating displacement, can not carry out phase
Modulation, the conspicuousness at edge is clearly；
3, step three of the invention, the low-frequency filter characteristics based on human eye vision are carrying out am screening processing to original copy
Afterwards, the dot location for changing regional area in mother matrix carries out phase-modulation, and anti-counterfeiting information is embedded into host image, reaches anti-
The hiding purpose of fake information；Advantage compared with prior art is：
(1), in the prior art, the phase modulation of site displacement is in order to realize Moire effect, it is contemplated that all sites into
The identical displacement of row, but for borderline part site, practical movably distance is between two site closest approaches
Distance is denoted as D1, in the state of the art, there has been no to the movable distance of boundary node relevant deeply grind
To study carefully, some few are also limited in the subjective judgement and theoretical foundation of shallow-layer, according to site displacement method, all site movements
Distance is D/2, and moving direction is the direction (i.e. along the cable direction of formation) of screen angle, is found in the present invention, works as D/2=
D1When, the site after moving at this time is just in contact with the site in front of it but does not overlap, due to meeting in early period halftone process
Screening parameter is set, therefore screen frequency is datum, screen frequency determines the distance between two neighboring site D and one
The length of side D of mesh tune unit2, D=D2, the distance between two site closest approaches D1Equal to the distance between two neighboring site D
The value for subtracting two radius r, in the case where screen frequency is certain, D1Site radius r is then depended on, and site radius depends on
In dot percentage α (i.e. the corresponding color value of pixel on channel), following formula is obtained：
Therefore, when D/2 is equal to D1When,Site after moving at this time is just in contact with the site in front of it but not
Overlap joint；In the prior art, there has been no the influences that research brings site displacement method in view of this threshold value；
When moving site according to site displacement method, borderline part site can take with the site in front of its moving direction
Connect, site overlap joint can cause anti-counterfeiting information concealment very big counter productive, the visual perception of lap-joint clearly, especially
It is the site of lap-joint or borderline site, and the profile of anti-counterfeiting information can be made just to be perceived by the human eye before extraction, led
Cause antiforge function failure；Therefore, in the present invention, only it is less than or equal in αWith reference to existing site displacement method；
When α is more thanWhen moving site according to traditional site displacement method (the mobile D/2 on screening direction), site choosing
The borderline part site in area is overlapped with the site in front of its moving direction, and site overlap joint can cause anti-counterfeiting information concealment non-
Often big counter productive, the visual perception of lap-joint clearly, the especially site of lap-joint or borderline site, meeting
So that the profile of anti-counterfeiting information is just perceived by the human eye before extraction, antiforge function is caused to fail；To ensure certain concealment, together
When ensure again borderline site can be extraction identity contribute, when site displacement distance S be maximum distance D1When, it carries
Performance is taken to reach best, it is specific as follows：
S=D1；
And because：
So
(2), in the prior art, the moving direction of phase modulation site is only and before and after screen angle direction or hangs down
Directly before and after screen angle direction, in conjunction with displacement distance, the last shift position in site is only this at 4, and the present invention is directed toHidden area each site, moveable position be a circular trace, with the center of circle of original site
For the center of circle of circular trace, using D/2 as the radius of circular trace, polar equation is：Such move mode can
To ensure that site phase-modulation still has good extraction performance and concealment in the case of as small as possible；ForHidden area each site, moveable position also be a circular trace, with the circle of original site
The heart is the center of circle of circular trace, with D1For the radius of circular trace, polar equation is：
4, step four of the invention designs different grating identification in conjunction with step 3 for different phase-modulation angles
Angle, β are 90 ° or 0 °, between the line and horizontal line in the center of circle when center of circle and home position after the movement of the site of set A
Angle be Ω, the present invention hides the angular dimension of the Ω in stage according to anti-counterfeiting information early period, studies it to cognitive phase grating
Influence, the angular dimension of Ω is classified so that it can identification when have corresponding grating identify angle；
5, step three of the invention further includes that will be embedded with the host image half-tone picture the output for printing for carrying anti-counterfeiting information,
Before the output for printing, setting identification label, identifies and is labeled as decussate texture on host image half-tone picture, decussate texture
The angle between horizontal line is β on one side, and step 4 further includes that the identification grating of digital document form is prepared into corresponding reality
Object light grid, identification label play indicative function, do not influence antiforge function, can aspect user's verification anti-counterfeiting information.
Description of the drawings
Attached drawing is used to provide further understanding of the present invention, and a part for constitution instruction, the reality with the present invention
It applies example to be used to explain the present invention together, not be construed as limiting the invention.In the accompanying drawings：
Fig. 1 is the host image in the embodiment of the present invention 1 (color information is not shown)；
The schematic diagram that Fig. 2 is site a on mother matrix in the embodiment of the present invention 1 (site is set as hollow in order to facilitate observation of)；
Fig. 3 is schematic diagram (the site setting in order to facilitate observation of of site a moveable positions on mother matrix in the embodiment of the present invention 1
It is hollow)；
Fig. 4 is the mother matrix half-tone picture in the embodiment of the present invention 1；
Fig. 5 is the host image half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention 1 (color information is not shown)；
Fig. 6 is that mother matrix screen angle and identification grating angle when being 0 ° in the embodiment of the present invention 1, site displacement are modulated
The schematic diagram of range；
Fig. 7 is the host image half-tone picture after covering identification grating in the embodiment of the present invention 1 (color information is not shown)；
Fig. 8 is the host image in the embodiment of the present invention 2 (color information is not shown)；
Fig. 9 is the mother matrix half-tone picture in the embodiment of the present invention 2；
Figure 10 is the host image half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention 2 (color information is not shown)；
Figure 11 for the host image half-tone picture after covering identification grating in the embodiment of the present invention 2, (do not show by color information
Go out)；
Figure 12 is the host image in the embodiment of the present invention 3 (color information is not shown)；
Figure 13 is the mother matrix half-tone picture in the embodiment of the present invention 3；
Figure 14 is the host image half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention 3 (color information is not shown)；
Figure 15 for the host image half-tone picture after covering identification grating in the embodiment of the present invention 3, (do not show by color information
Go out)；
Specific implementation mode
Present invention will be further explained below with reference to specific examples.These embodiments are merely to illustrate the present invention and do not have to
In limiting the scope of the invention.In conjunction with Figure of description, the design feature that the present invention will be described in detail.
Embodiment 1
A kind of hiding and extracting method for the anti-counterfeiting information that mother matrix screen angle is 0 degree, includes the following steps：
Step 1: selection host image and determining hidden area
Selection needs to carry out the hiding host image of anti-counterfeiting information, and the condition that host image need to meet is：
(1), it is made of m*n pixel, color mode is CMYK (i.e. by C-channel, the channels M, the channels Y and K channel group
At)；
(2), there is the hidden area that anti-counterfeiting information can be arranged, hidden area tool at least one channel of host image
There are s*s pixel, s to be respectively less than m and n, the channel where hidden area is mother matrix, and remaining channel is 3 secondary versions, on mother matrix
The position for determining hidden area remembers that color value of all pixels point of hidden area on mother matrix is identical, is denoted as α, α is ranging from
0.1~0.5；
In this implementation, what is obtained meets the input resolution ratio of the host image of condition for 2400lpi, m=n=3780, s=
1260, the length and width of host image are 4cm, and the value of α is 0.15 in obtained hidden area；
Step 2: host image halftone process
Host image is opened in photoshop, screening processing adjusts screen using half in photoshop；To 4 channels
Screening parameter is respectively set and carries out screening processing, screening processing adjusts screen using half, and screening parameter includes output resolution ratio, screening
Line number, dot shape and screen angle, when carrying out screening processing respectively to 4 channels, using identical output resolution ratio, screening
Line number and dot shape, dot shape are circle, in this implementation screen frequency be 96lpi, output resolution ratio 2400dpi,
The screen angle θ of mother matrix is 0 °, the arbitrary combination that the screen angles of 3 secondary versions is 15 °, 45 ° and 75 °；θ is 0 ° in the present embodiment
The difficulty of hiding anti-counterfeiting information can be reduced；
Wherein, the method for each channel progress screening processing is：Channel is chosen, channel is converted into bitmap, when conversion sets
It is 2400dpi to set the output resolution ratio, then adjusts screen to the processing of channel screening using half according to aforementioned screening parameter；It obtains
The mother matrix half-tone picture and 3 width pair version half-tone pictures be made of site；
Step 3: anti-counterfeiting information is hidden
It chooses and needs hiding anti-counterfeiting information, in the present embodiment, anti-counterfeiting information is figure and literary combinatorics on words, according to its wheel
Exterior feature establishes site constituency in corresponding hidden area, and the method for establishing site constituency is：
(1), in photoshop softwares, new image one, the length and width of image one are identical with the length and width of host image, i.e.,
Length and width are 4cm, and the input resolution ratio of image one is 2400dpi, and background content is white, and " figure layer is obtained in figure layer channel
0 ", the mother matrix half-tone picture is copied into image one, is obtained " figure layer 1 ", replicates " figure layer 1 ", obtains " figure layer 2 "；By " figure layer
2 ", " figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window；
(2), " figure layer 3 " is created, " figure layer 3 ", " figure layer 2 ", " figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window
In, it is placed in anti-counterfeiting information in " figure layer 3 ", anti-counterfeiting information is moved to the corresponding position of hidden area, " figure layer 3 " is chosen, makes
Anti-counterfeiting information is chosen with magic wand menu, obtains site constituency, then setting " figure layer 3 " is invisible, " figure layer 2 " is chosen, at this point, net
The site that point constituency is chosen out in " figure layer 2 " is the site for needing to carry out phase-modulation, is denoted as set A；
Such phase modulation method be：Identical angle and distance is moved in all sites of set A, remembers in set A
Any site a, by taking a of the site as an example, the modulator approach of remaining site is identical, referring to Fig. 2 and Fig. 3, with the central point of site a
Q is that pole establishes polar coordinates, and the position that site a moves rear center's point is q ', and the polar coordinates of q ' are (ρ, γ), and ρ moves for site a
Distance, γ is the angle between the line and horizontal line of the central point of the central point and home position after the movement of site, and q ' is
The moveable position at any point on polar equation ρ, q ' is the dashed trace formd in Fig. 2, adjacent after remembering screening
The distance between two sites be D (in known in this field,), dashed trace is circle, and its radius is equal to D/2,
Therefore, the polar equation of dashed trace is：Site a is moved to any point in dashed trace, it can be with
Realize the hiding and identification of anti-counterfeiting information；
After the completion of phase-modulation, referring to Fig. 4, the mother matrix half-tone picture for carrying anti-counterfeiting information is obtained, by itself and 3 width pair versions half
Tone illustration carries out image synthesis, and new image two in photoshop, the length and width of image two are identical with the length and width of host image,
The input resolution ratio of image two is identical with the output resolution ratio, and background content is white, and color mode is CMKY patterns, will
The mother matrix half-tone picture and 3 width pair version half-tone pictures are copied into corresponding Color Channel, referring to Fig. 5, obtain carrying anti-fake
The host image half-tone picture of information completes hiding for anti-counterfeiting information；
Step 4: the identification of anti-counterfeiting information
Make identification grating：The identification grating for preparing digital document form identifies that the area of grating is more than hidden area
Area, identification grating is mutually parallel to be alternatively arranged by the identical blackstreak of length and transparent stripe to be formed, the width of blackstreak
Degree is T1, the width of transparent stripe is T2(in known in this field,)；
T1Determination method be：To form Moire fringe, T is designed1=2r so that in extraction process, present a contrast and make
Anti-counterfeiting information shows, r represents the radius of site, and becauseTherefore T1=2r is equivalent to：
To further,The width of identification grating blackstreak and transparent stripe is determined with this；
Identify anti-counterfeiting information：It will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation is known
Other grating so that the angle between identification grating and horizontal line is β, is then moved forward and backward identification grating along the directions β, until set
The site of A forms the anti-counterfeiting information with powerful contrast with identification grating, and to complete the identification of anti-counterfeiting information, it is anti-to obtain extraction
The stacking chart of the identification grating and host image half-tone picture of fake information, the determination method of angle β are：
(1), referring to Fig. 6, when Fig. 6 is that mother matrix screen angle and identification grating angle are 0 ° in the embodiment of the present invention 1, net
The schematic diagram of the point modulated range of displacement；When the center of circle q displaced positions of site a are q ' in Fig. 3,4 shown in h1, h2 and h3
When position, in the identification anti-counterfeiting information stage, at this 4 positions, site and angle after movement are 0 ° of identification grating just phase
Cut, when its continuation close to identification grating movement when, use angle for 90 ° of identification grating after its extract resolution higher；
(2), when remembering tangent, the angle between the line and screen angle direction of the center of circle q ' and q is Ω, the center of circle h1's and q
Angle between line and screen angle direction is Ω 1, and the angle between the line and screen angle direction of the center of circle h2 and q is Ω
2, the angle between the line and screen angle direction of the center of circle h3 and q is Ω 3；Again because aforementioned, γ is the circle after the movement of site
Angle between the heart and the circular line and horizontal line in home position, in the present embodiment, screen angle is 0 °, therefore, corresponding
, as Ω≤γ≤ΩlOr Ω2≤γ≤Ω3When, use angle β to be identified for 0 °, remaining section then uses angle β
It is identified for 90 °；
(3), further, referring to Fig. 3, the computational methods of Ω are as follows：
Then correspondence calculates Ω1、Ω2、Ω3, obtain the determination method of following angle β：
WhenWhen, β=0 °；
WhenWhen, β=90 °.
Furtherly,
Further include that will be embedded with the host image half-tone picture the output for printing for carrying anti-counterfeiting information in the step 3, print
Before brushing output, the setting identification label on host image half-tone picture identifies and is labeled as decussate texture, the one of decussate texture
Angle between side and horizontal line is β, and then control exposure output by output equipment is made film at printing plate, or correspondence
Seal carving version is shone again, and the host image for obtaining carrying anti-counterfeiting information is in kind；
Further include that the identification grating of digital document form is prepared into corresponding grating in kind in the step 4, it will be real
Object light grid are covered on host image material object, and rotation grating in kind is marked according to identification so that the blackstreak of grating in kind or
Person's transparent stripe and horizontal angle are β, are then moved forward and backward grating in kind along the directions β, until observe anti-counterfeiting information, it is complete
At identification.
Furtherly,
In the present embodiment step 4, the production method for identifying grating is：
(1), photoshop softwares are opened, create figure layer X, background colour is set as transparent (no background colour), then the figure built
The first rectangle of a length and width particular value is drawn on layer with the rectangle tool, then Fill Color (is preferably in the rectangle frame finished
Black), then the second rectangle that a width is equal with the first rectangle, length is more than the first rectangle is drawn in the same way, and
It is sleeved on the first rectangle, the first rectangle is located at the bottom in the second rectangle, then selects " editor/definition pattern ", will be ready-made
Pattern saves as " pattern 0 "；Wherein, the length of the first rectangle is T1, the length of the second rectangle is T1+T2, as mesh tune
The length of side of unit, also the distance D between as two neighboring site；
(2), delete layer X, then builds a new figure layer again and be named as figure layer Z, and the size of figure layer Z is to decode straight line
The size of grating, resolution ratio is identical with the output resolution ratio, then using " pattern 0 " preserved come Photoshop Z, after filling
Form the identification grating for detecting anti-counterfeiting information.
Concealment is evaluated：
The mother matrix half-tone picture of carrying anti-counterfeiting information in embodiment 1 is carried out image with 3 width pair version half-tone pictures to synthesize,
Obtain carrying the host image half-tone picture of anti-counterfeiting information；Using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio)
Evaluation is not embedded into the host image half-tone picture of anti-counterfeiting information and carries both host image half-tone pictures of anti-counterfeiting information respectively
Between similarity, to obtain the concealed evaluation result of hiding information indirectly, as shown in table 1 below：
1 embodiment of table, 1 similarity evaluation result
Wherein, the value of SSIM is bigger closer to the value of 1 or WSNR, and the similarity for representing two images is bigger, by upper
Table 1 is stated it is found that the SSIM values of embodiment 1 are close to 1, and WSNR is larger, therefore the method for the present invention, concealment effect is good, no
Easily it is detected by human eye.
Extract identity evaluation：
Using region contrast function FiWith comentropy function algorithm Ti, the values of the two algorithms be all between 0 and 1 it
Between numerical value, FiAnd TiValue closer to 1, the background reflectance for representing security pattern and host image that grating identifies is bigger, figure
As more clear notable：
(1), region contrast function Fi
Above formula is the saliency evaluation function based on region contrast, and dev (x, y) indicates region pair defined above
Degree of ratio；maxf△(x, y) and minf△(x, y) respectively represents gray scale maximum value and minimum value in the region, 0≤dev (x, y)
≤1；
(2), comentropy function algorithm Ti
Above formula is information entropy function, pkIndicate that the frequency that gray value k occurs in the images, N indicate the gray scale etc. of image
Grade.
Using region contrast function FiWith comentropy function algorithm TiRespectively evaluation extraction anti-counterfeiting information identification grating and
The stacking chart of host image half-tone picture, obtained result are as shown in table 2 below：
2 embodiment 1 of table extracts identity evaluation result
Wherein, FiAnd TiValue closer to 1, the background reflectance for representing security pattern and host image that grating identifies is got over
Greatly, image is more clear significantly, the F of embodiment 1iAnd TiValue be all higher than 0.5, therefore the method for the present invention extracts recognition performance
It is good.
Embodiment 2
Referring to Fig. 8~11, on the basis of embodiment 1, embodiment 2 the difference is that：(1), host image is different；
(2), anti-counterfeiting information is word；(3), 0.1 α；
Concealment is evaluated：
The mother matrix half-tone picture of carrying anti-counterfeiting information in embodiment 2 is carried out image with 3 width pair version half-tone pictures to synthesize,
Obtain carrying the host image half-tone picture of anti-counterfeiting information；Using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio)
Evaluation is not embedded into the host image half-tone picture of anti-counterfeiting information and carries both host image half-tone pictures of anti-counterfeiting information respectively
Between similarity, to obtain the concealed evaluation result of hiding information indirectly, as shown in table 3 below：
3 embodiment of table, 2 similarity evaluation result
Wherein, the value of SSIM is bigger closer to the value of 1 or WSNR, and the similarity for representing two images is bigger, by upper
Table 3 is stated it is found that the SSIM values of embodiment 2 are close to 1, and WSNR is larger, therefore the method for the present invention, concealment effect is good, no
Easily it is detected by human eye.
Extract identity evaluation：
Using region contrast function FiWith comentropy function algorithm Ti, the identification grating of extraction anti-counterfeiting information is evaluated respectively
With the stacking chart of host image half-tone picture, obtained result is as shown in table 4 below：
4 embodiment 2 of table extracts identity evaluation result
Wherein, FiAnd TiValue closer to 1, the background reflectance for representing security pattern and host image that grating identifies is got over
Greatly, image is more clear significantly, the F of embodiment 1iAnd TiValue be all higher than 0.5, therefore the method for the present invention extracts recognition performance
It is good.
Embodiment 3
Referring to Figure 12~15, on the basis of embodiment 1, embodiment 3 the difference is that：(1), host image is not
Together；(2), anti-counterfeiting information is figure；(3), 0.25 α；
Concealment is evaluated：
The mother matrix half-tone picture of carrying anti-counterfeiting information in embodiment 3 is carried out image with 3 width pair version half-tone pictures to synthesize,
Obtain carrying the host image half-tone picture of anti-counterfeiting information；Using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio)
Evaluation is not embedded into the host image half-tone picture of anti-counterfeiting information and carries both host image half-tone pictures of anti-counterfeiting information respectively
Between similarity, to obtain the concealed evaluation result of hiding information indirectly, as shown in table 5 below：
5 embodiment of table, 3 similarity evaluation result
Wherein, the value of SSIM is bigger closer to the value of 1 or WSNR, and the similarity for representing two images is bigger, by upper
Table 5 is stated it is found that the SSIM values of embodiment 3 are close to 1, and WSNR is larger, therefore the method for the present invention, concealment effect is good, no
Easily it is detected by human eye.
Extract identity evaluation：
Using region contrast function FiWith comentropy function algorithm Ti, the identification grating of extraction anti-counterfeiting information is evaluated respectively
With the stacking chart of host image half-tone picture, obtained result is as shown in table 6 below：
6 embodiment 3 of table extracts identity evaluation result
Wherein, the value of Fi and Ti closer to 1, get over by the background reflectance for representing security pattern and host image that grating identifies
Greatly, image is more clear significantly, and the value of the Fi and Ti of embodiment 3 are all higher than 0.5, therefore the method for the present invention, extract recognition performance
It is good.
Claims (10)
1. a kind of hiding and extracting method for the anti-counterfeiting information that mother matrix screen angle is 0 degree, which is characterized in that including walking as follows
Suddenly：
Step 1: setting host image and determining hidden area
Host image is set, and host image is the digital document being made of m*n pixel, and has 4 Color Channels, color
Channel is made of C-channel, the channels M, the channels Y and K channel；
There is the hidden area that anti-counterfeiting information can be arranged, hidden area to have s*s picture at least one channel of host image
Vegetarian refreshments, s are respectively less than m and n, and the channel where hidden area is mother matrix, and remaining channel is 3 secondary versions, determines and hides on mother matrix
The position in region remembers that color value of all pixels point of hidden area on mother matrix is identical, is denoted as α, α ranging from 0.1~
0.5；
Step 2: host image halftone process
Screening parameter is respectively set to 4 channels and carries out screening processing, screening processing adjusts screen using half, and screening parameter includes defeated
Go out resolution ratio, screen frequency, dot shape and screen angle, when carrying out screening processing respectively to 4 channels, using identical defeated
Go out resolution ratio, screen frequency and dot shape, dot shape is circle, and the screen angle of mother matrix is 0 °, is obtained by site group
At mother matrix half-tone picture and 3 width pair version half-tone pictures；
Step 3: anti-counterfeiting information is hidden
It chooses and needs hiding anti-counterfeiting information, mother matrix half-tone picture is opened in image processing software, according to the wheel of anti-counterfeiting information
Exterior feature establishes site constituency in corresponding hidden area, remembers that the site in the constituency of site is set A, the site of set A is carried out
Phase-modulation；
The method for building up in site constituency is：
(1), in photoshop softwares, new image one, the length and width of image one are identical with the length and width of host image, image one
Input resolution ratio it is identical with the output resolution ratio, background content be white, " figure layer 0 " is obtained in figure layer channel, by institute
It states mother matrix half-tone picture and is copied into image one, obtain " figure layer 1 ", replicate " figure layer 1 ", obtain " figure layer 2 "；By " figure layer 2 ", " figure
Layer 1 " and " figure layer 0 " are sequentially arranged in figure layer window；
(2), " figure layer 3 " is created, " figure layer 3 ", " figure layer 2 ", " figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window,
It is placed in anti-counterfeiting information in " figure layer 3 ", anti-counterfeiting information is moved to the corresponding position of hidden area, " figure layer 3 " is chosen, uses magic stick
Tool chooses anti-counterfeiting information, obtains site constituency, and setting " figure layer 3 " is invisible；
The method of phase-modulation is：Move identical angle and distance, any site in note set A in all sites of set A
A establishes polar coordinates by pole of the central point q of site a, and the position that site a moves rear center's point is q ', and the polar coordinates of q ' are
(ρ, γ), q ' are any point on polar equation ρ, and the value of ρ is the distance of site a movements, γ be after site a movements in
Angle between the line and horizontal line of central point before heart point and movement remembers that the screen frequency is l, and polar equation ρ is：
After the completion of phase-modulation, the mother matrix half-tone picture for carrying anti-counterfeiting information is obtained, itself and 3 width pair version half-tone pictures are subjected to figure
As synthesis, the host image half-tone picture for carrying anti-counterfeiting information is obtained；
Step 4: the identification of anti-counterfeiting information
Make identification grating：The identification grating for preparing digital document form identifies that the area of grating is more than the area of hidden area,
Identification grating is mutually parallel to be alternatively arranged by the identical blackstreak of length and transparent stripe to be formed, and the width of blackstreak is
T1, the width of transparent stripe is T2, wherein
Identify anti-counterfeiting information：It will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation identification light
Grid so that the angle between identification grating and horizontal line is β, is then moved forward and backward identification grating along the directions β, until set A
Site forms the anti-counterfeiting information with powerful contrast with identification grating, to complete the identification of anti-counterfeiting information, the determination side of angle β
Method is：
WhenWhen, β=0 °；
WhenWhen, β=90 °.
2. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：In the step 2, host image halftone process is completed in photoshop softwares, and host is opened in photoshop
Image, the screening processing adjust screen using half in photoshop；
Each the method for channel progress screening processing is：Channel is chosen, channel is converted into bitmap, the output is arranged in when conversion
Then resolution ratio adjusts screen to the processing of channel screening using half, the screen frequency is 90~200lpi.
3. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：The arbitrary combination that the screen angle of described 3 secondary versions is 15 °, 45 ° and 75 °.
4. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：The arbitrary combination that the screen angle of described 3 secondary versions is 18.44 °, 45 ° and 71.57 °.
5. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：Further include that will be embedded with the host image half-tone picture the output for printing for carrying anti-counterfeiting information in the step 3, the output for printing
Before, the setting identification label on host image half-tone picture, identification is labeled as decussate texture, one side of decussate texture and water
Angle between horizontal line is the β, and then control exposure output by output equipment is made film again at printing plate, or correspondence
Seal carving version is shone, the host image for obtaining carrying anti-counterfeiting information is in kind；
Further include that the identification grating of digital document form is prepared into corresponding grating in kind, by light in kind in the step 4
Grid are covered on host image material object, mark rotation grating in kind according to identification so that the blackstreak of grating in kind is saturating
Bright fringe and horizontal angle are the β, are then moved forward and backward grating in kind along the directions β, until observe anti-counterfeiting information, it is complete
At identification.
6. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：In the step 3, image synthetic method is：
New image two in photoshop, the length and width of image two are identical with the length and width of host image, and the input of image two is differentiated
Rate is identical with the output resolution ratio, and background content is white, and color mode is CMKY patterns, by the mother matrix half-tone picture and
3 width pair version half-tone pictures be copied into corresponding Color Channel to get.
7. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：The output resolution ratio is the integral multiple of screen frequency.
8. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：The output resolution ratio is 2400dpi, screen frequency 96lpi.
9. hiding and extracting method, the feature of the anti-counterfeiting information that mother matrix screen angle according to claim 1 is 0 degree exist
In：The output resolution ratio is 1440dpi, screen frequency 96lpi.
10. the anti-fake host image processing method of the grating according to claim 1 for improving recognition performance, feature exist
In：The output resolution ratio is 1920dpi, screen frequency 96lpi.
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| CN109493358A (en) * | 2018-12-14 | 2019-03-19 | 中国船舶重工集团公司第七0七研究所 | A kind of error feedback halftoning algorithm based on human vision model |
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