CN108876695A - A method of the hiding anti-counterfeiting information before printed matter output - Google Patents
A method of the hiding anti-counterfeiting information before printed matter output Download PDFInfo
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- CN108876695A CN108876695A CN201810572244.5A CN201810572244A CN108876695A CN 108876695 A CN108876695 A CN 108876695A CN 201810572244 A CN201810572244 A CN 201810572244A CN 108876695 A CN108876695 A CN 108876695A
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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
- G06T1/0021—Image watermarking
Abstract
The invention discloses a kind of methods of anti-counterfeiting information hiding before printed matter output, include the following steps：Step 1: selection and decomposition host image；Step 2: determining the hidden area of host image and anti-counterfeiting information:There is the hidden area that anti-counterfeiting information can be set at least one Color Channel of host image, hidden area has s*s pixel, Color Channel where remembering hidden area is mother matrix, and color value of all pixels point of hidden area on mother matrix is all the same, it is denoted as α, remaining Color Channel is 3 secondary versions；Step 3: host image halftone process；Step 4: anti-counterfeiting information is hidden：It chooses and needs hiding anti-counterfeiting information, site constituency is established in corresponding hidden area according to the profile of anti-counterfeiting information in image processing software；Step 5: the identification of anti-counterfeiting information.The present invention expands the modulated angular range in site.
Description
Technical field
The invention belongs to grating field of anti-counterfeit technology, and in particular to a kind of side of anti-counterfeiting information hiding before printed matter output
Method.
Background technique
The limit resolution capability of human eye normal vision is limited, the size of dot of image after digital screening and site
When spacing is less than the limit resolution capability of human eye vision, human eye cannot distinguish site.So the binary map of actually 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,
It namely cannot distinguish between image detail, the image effect finally continuously adjusted to people's one kind, to realize the printing of continuous tone
Duplication.
It is anti-counterfeiting technology that halftone screen technology and Moire effect combine 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 the anti-counterfeiting information that is embedded in 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, hiding information is embedded among 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 respectively indicate 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 in existing some progress, also has using the way perpendicular to the mobile D/2 in screen angle direction, by
In certainly will be arranged screen frequency l in image halftoning process, therefore D is a known numeric value,
Although phase modulation, using very universal, there is also following deficiencies：
1, there are far-reaching technology prejudice for optimal site principle：Existing research thinks that the displacement setting of site must expire
When the site of the optimal site principle of foot, only composition anti-counterfeiting information is located at optimal dot location, digital raster detection is anti-fake
When information, the reproduction of anti-counterfeiting information is just most obvious, clear, but it is inclined to always exist the used technology having for many years in the prior art
See, it is believed that optimum point only moves D/2 along the vertical direction in screen angle direction or screen angle, causes from theoretical direction
Angle on site it is modulated angle and distance it is very limited；
2, overlapped Study on Problems is generated without in place to site：In order to realize Moire effect, it is contemplated that site constituency
All sites carry out identical displacement, and direction of displacement is the direction vertical along screen angle direction or screen angle, displacement
Distance is D/2, simultaneously as screening parameter can be arranged in early period halftone process, therefore screen frequency is datum, screening line
Number has determined the side length D of D and single mesh tune unit2, D=D2, therefore, D/2 is definite value；But it is located on the selection border of site
Part site, practical movably distance is the distance between two site closest approaches, is denoted as D1, with dot percentage
Increase, D1It can be gradually reduced, therefore, D1For variable；Work as D1When less than D/2, if the method still according to the prior art carries out phase
Position modulation, then can cause the overlap joint on boundary between site, cause strong visual perception, so that anti-fake failure, the prior art
In not yet consider actual range between site to concealment and extract the synergy that performance generates.
Summary of the invention
The object of the present invention is to provide a kind of methods of anti-counterfeiting information hiding before printed matter output, and it is adjustable to expand site
The angular range of system optimizes the modulated distance in site, improves the concealment and extraction effect of anti-counterfeiting information.
The present invention provides the following technical solutions：A method of the hiding anti-counterfeiting information before printed matter output, including
Following steps：
Step 1: selection and decomposition host image
Host image is randomly choosed, host image is the digital document being made of m*n pixel；
The image model of host image is arranged to CMYK mode, host image is decomposed, leads to it by C-channel, the channel M, Y
Totally 4 Color Channels form for road and K channel；
Step 2: determining the hidden area of host image and anti-counterfeiting information
There is the hidden area that anti-counterfeiting information can be set, hidden area tool at least one Color Channel of host image
There is s*s pixel, the Color Channel where remembering the hidden area is mother matrix, and all pixels point of hidden area is in mother matrix
On color value it is all the same, be denoted as α, α is 0.1~0.5；Remaining Color Channel is 3 secondary versions；
When can not select α be 0.1~0.5 hidden area when, then return step one reselect host image again into
Row host image decomposes, until finding the hidden area that α is 0.1~0.5；
Step 3: host image halftone process
Screening parameter is respectively set to 4 Color Channels and carries out screening processing, obtains the mother matrix halftoning being made of site
Figure and 3 width pair version half-tone pictures；
Step 4: 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 of phase-modulation is：Remember any site e in set A, pole is established as pole using the central point q of site e
Coordinate, the position of the mobile rear center's point of site e are q ', and the polar coordinates of q ' are (ρ, γ), and it is radius that q ', which is by the center of circle, ρ of pole,
And any point in the circular trace with 4 notches, by the mobile angle identical with site e in remaining site of set A and away from
From screening parameter includes screen angle and screen frequency, remembers that the screen angle of mother matrix is θ, θ=0 ° remembers that the screen frequency is
l；
The α value obtained according to step 1, whenWhen, the radius of the circular trace with 4 notches isEquation of locus is：
WhenWhen, the radius of the circular trace with 4 notches isEquation of locus is：
WhenWhen, the radius of the circular trace with 4 notches isTrack side
Cheng Wei：
Step 5: the identification of anti-counterfeiting information
(1), production identification grating：The identification grating for preparing digital document form identifies that the area of grating is greater than hidden area
The area in domain, identification grating is parallel to each other to be alternatively arranged by the identical blackstreak of length and transparent stripe to be formed, blackstreak
Width be T1, the width of transparent stripe is T2, wherein
(2), it will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation identification grating makes
It must identify that it is β that angle is formed between grating and horizontal line, is then moved forward and backward identification grating along the direction β, until the site of set A
The anti-counterfeiting information with powerful contrast is formed with identification grating, to complete the identification of anti-counterfeiting information；
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
The synthesis of row image obtains the host image half-tone picture for carrying anti-counterfeiting information, completes hiding for anti-counterfeiting information.
It is as above-mentioned technical proposal to further describe：
In the step 3, screening processing adjusts screen using half in photoshop software, and screening parameter further includes output
Resolution ratio and dot shape, when carrying out screening processing respectively to 4 Color Channels, using identical output resolution ratio, screening line
Several and dot shape, any combination that the screen angle of 3 secondary versions is 15 °, 45 ° and 75 °.
It is as above-mentioned technical proposal to further describe：
The dot shape is circle, in the step 2, s < m and s < n.
It is as above-mentioned technical proposal to further describe：
The determination method of the β is：
It is as above-mentioned technical proposal to further describe：
In the step 2, screening processing adjusts screen using half in photoshop software, and screening parameter further includes output
Resolution ratio and dot shape, when carrying out screening processing respectively to 4 Color Channels, using identical output resolution ratio, screening line
Several and dot shape, any combination that the screen angle of 4 Color Channels is 0 °, 18.44 °, 45 ° and 71.57 °, output are differentiated
Rate is 2400dpi, screen frequency 96lpi.
It is as above-mentioned technical proposal to further describe：
It 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 4, print
Before brushing output, the setting identification label on host image half-tone picture identifies and is labeled as cross-shaped structure, the one of cross-shaped structure
Angle between side and horizontal line is the β, then controls exposure output by output equipment and phenanthrene is made at printing plate, or correspondence
Forest tract shines seal carving version again, and the host image for obtaining carrying anti-counterfeiting information is in kind；
It is as above-mentioned technical proposal to further describe：
It further include that the identification grating of digital document form is prepared into corresponding grating in kind in the step 5, it will be real
Object light grid are covered on host image material object, are marked according to identification and are rotated grating in kind so that the blackstreak of grating in kind or
Person's transparent stripe and horizontal angle are the β, then grating in kind are moved forward and backward along the direction β, until observing anti-fake letter
Breath completes identification.
It is as above-mentioned technical proposal to further describe：
In the step 4, the method for building up in site constituency is：
(1), in photoshop software, new image one, the length and width of image one and the length and width of host image are identical, 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.
Beneficial effects of the present invention：The modulated angular range in site is expanded, the modulated distance in site is optimized, mentions
The high concealment and extraction effect of anti-counterfeiting information, it is specific as follows：
1, the threshold value that generates that overlapped for site is determined：It is found in the present invention, works as D/2=D1When, at this point, being located at site constituency side
Part site in boundary is just in contact with the site in front of it but does not overlap, D after mobile1Equal between two neighboring site
Distance D subtract the value of two radius r, in the case where screen frequency is certain, D1Site radius r is then depended on, and site is partly
Diameter depends on the corresponding color value α (i.e. dot percentage) of pixel on channel, obtains following formula：Therefore, when D/2 is equal to D1
When,Site after moving at this time is just in contact with the site in front of it but does not overlap；In the prior art, there has been no
Research influences site displacement method bring in view of this threshold value；
2, the distance that site is mobile in phase-modulation is optimized：Based on aforementioned, only it is less than or equal in α in the present inventionGinseng
Existing site displacement method is examined, i.e. the mobile distance in site is D/2, asWhen α is greater thanTo guarantee centainly hidden
Covering property, at the same guarantee again borderline site can for extract identity contribute, site moving distance S be two sites most
The distance between near point D1, as
3, the direction that site is mobile in phase-modulation is optimized
In the prior art, the moving direction of phase modulation site be only along screen angle direction front and back or perpendicular to
The front and back in screen angle direction, in conjunction with moving distance, the last shift position in site is only the phase at 4, after present invention optimization
Modulator approach, the moveable position composition in site have the circular trace of notch at 4, and the polar equation of the track is：
WhenWhen, each site in the constituency of site, its own modulated position composition with lacking everywhere
The circular trace of mouth, the radius of the circular trace areEquation of locus is：And
WhenWhen, each site in the constituency of site, its own modulated position composition with lacking everywhere
The circular trace of mouth, the radius of the circular trace areEquation of locus is：
And
Therefore, phase-modulation is carried out using method of the invention, has overturned the technology prejudice of the prior art, determination is reaching
On the basis of identical concealment effect, the modulated range in site is expanded；
4, the identification angle of design identification grating
According to the equation of locus of previous designs, when extracting hiding anti-counterfeiting information using identification grating, accurate extract is remembered
Out when anti-counterfeiting information, identify that the angle (acute angle) between grating and horizontal line is β：
Different β is used according to the angle of site modulation, prevents the site in site constituency to be overlapped with identification grating generation, drops
The conspicuousness of low extraction；
5, the scope of application of the present invention is wider, more flexible：Step 1 and two can determine hidden area on Color Channel
Color value, in halftone process, color value α corresponds to the dot percentage of site, indirectly determines phase modulated
The distance that site is displaced in journey, step 1 have determined the data such as color mode and the image size of host image, have further defined mother
The specific location of version, hidden area, opens host image in photoshop, and observation colouring information finds corresponding hidden area
Domain, it is easy to operate；Host image can be the original copy directly made in image processing software, be also possible to the symbol randomly selected
The original copy of conjunction condition；
6, the present invention guarantees good information hiding and extractability in terms of the selection of host image：Only consider 0.1~
0.5 range, because in actual operation, testing and finding by many experiments, when dot percentage is less than 0.1, anti-fake letter
The concealment of breath is very good, but it is very poor to extract recognition performance；When dot percentage is greater than 0.5, the extraction of anti-counterfeiting information is known
Other better performances, but concealment is weaker, to reach best concealment and extractability, in addition, in actual operation, site hundred
Divide than when reaching 0.5, in the half-tone picture after using photoshop screening (dot shape is circle), two neighboring site exists
The case where not generating displacement has contacted with each other, and can not carry out phase-modulation, the conspicuousness at edge is clearly；
7, the present invention has practical application value：The host image half-tone picture printing that carrying anti-counterfeiting information will be embedded with is defeated
Out, before the output for printing, setting identification label, identification are labeled as cross-shaped structure, cross knot on host image half-tone picture
Angle between one side and horizontal line of structure is β, and step 4 further includes that the identification grating of digital document form is prepared into correspondence
Grating in kind, identification label play indicative function, do not influence antiforge function, can aspect user verify anti-counterfeiting information.
Detailed description of the invention
Attached drawing is used to provide further understanding of the present invention, and constitutes part of specification, with reality of the 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)；
Fig. 2 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. 3 is the host image half-tone picture in the embodiment of the present invention 1 after covering identification grating (color information is not shown)；
Fig. 4 is the host image in the embodiment of the present invention 2 (color information is not shown)；
Fig. 5 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)；
Fig. 6 is the host image half-tone picture in the embodiment of the present invention 2 after covering identification grating (color information is not shown)；
Fig. 7 is the host image in the embodiment of the present invention 3 (color information is not shown)；
Fig. 8 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)；
Fig. 9 is the host image half-tone picture in the embodiment of the present invention 3 after covering identification grating (color information is not shown)；
The schematic diagram that Figure 10 is any site e on a mother matrix in the present invention (site is set as hollow in order to facilitate observation of)；
Figure 11 is schematic diagram (the site setting in order to facilitate observation of of any site e moveable position on a mother matrix in the present invention
It is hollow)；
Figure 12 is the schematic diagram (net in order to facilitate observation of in the present invention on a mother matrix after any site e moveable position optimization
Point is set as hollow)；
Figure 13 is the rough schematic view of Figure 12 of the present invention；
The state tangent with identification grating is illustrated after any site e is mobile on one mother matrix when Figure 14 is β=θ in the present invention
Figure；
The state tangent with identification grating is shown after any site e is mobile on one mother matrix when Figure 15 is+90 ° of β=θ in the present invention
It is intended to；
Figure 16 is the schematic diagram of the moveable position of part range in Figure 12 of the present invention；
Specific embodiment
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.Now in conjunction with Figure of description, the design feature that the present invention will be described in detail.
Embodiment 1
A method of the hiding anti-counterfeiting information before printed matter output includes the following steps：
Step 1: selection and decomposition host image
Host image is randomly choosed, for hiding anti-counterfeiting information, the condition which need to meet is：
(1), the digital document being made of m*n pixel；
(2), image model is arranged to CMYK mode, decomposes host image by the present embodiment 1 in photoshop software,
Making it by C-channel, the channel M, the channel Y and K channel, totally 4 Color Channels form；
Step 2: determining the hidden area of host image and anti-counterfeiting information
There is the hidden area that anti-counterfeiting information can be set, hidden area tool at least one Color Channel of host image
There is s*s pixel, the Color Channel where remembering the hidden area is mother matrix, and all pixels point of hidden area is in mother matrix
On color value it is all the same, be denoted as α, α is 0.1~0.5；Remaining Color Channel is 3 secondary versions；
When can not select α be 0.1~0.5 hidden area when, then return step one reselect host image again into
Row host image decomposes, until finding the hidden area that α is 0.1~0.5；
Referring to Fig. 1, in the present embodiment 1, by step 1 and step 2, what is obtained meets the host image of condition, from
The input resolution ratio of band is 2400lpi, m=n=3780, s=1260, and the length and width of host image are 4cm, obtained hidden area
The value of α is 0.15 in domain；Mother matrix is C-channel, and the channel M, the channel Y and K channel are secondary version；
Step 3: host image halftone process
Screening parameter is respectively set to 4 Color Channels and carries out screening processing, specially：
Host image is opened in photoshop, chooses single Color Channel, Color Channel is converted into bitmap, is converted
When setting output resolution ratio be 2400dpi, then adjust screen to carry out screening using half in photoshop, screening parameter includes
Output resolution ratio, screen frequency, dot shape and screen angle are all made of identical output resolution ratio to 4 Color Channels, add
Screen density and dot shape carry out screening, and dot shape is circle, and screen frequency is 96lpi in the present embodiment 1, C-channel
Screen angle is 0 °, and the screen angle in the channel M, the channel Y and K channel is respectively 15 °, 45 ° and 75 °；
It is repeated 4 times aforementioned operation, obtains the mother matrix half-tone picture being made of site and 3 width pair version half-tone pictures；
Step 4: anti-counterfeiting information is hidden
(1), site constituency is established
It chooses and needs hiding anti-counterfeiting information, in embodiment, anti-counterfeiting information is figure and literary combinatorics on words, in image procossing
Mother matrix half-tone picture is opened in software, site constituency is established in corresponding hidden area according to the profile of anti-counterfeiting information, is established
The method in site constituency is：
A, in photoshop software, new image one, the length and width of image one and the length and width of host image are identical, i.e., long
Width is 4cm, and the input resolution ratio of image one is 2400dpi, 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；
B, " 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 evil spirit
Stick tool chooses anti-counterfeiting information, obtains site constituency, and then setting " figure layer 3 " is invisible, chooses " figure layer 2 ", at this point, site is selected
The site that area chooses out in " figure layer 2 " is the site for needing to carry out phase-modulation, is denoted as set A；
(2), phase-modulation
The site of set A is subjected to phase-modulation, method is：
A, remember any site e in set A, polar coordinates are established by pole of the central point q of site e, after site e is mobile
Central point is q ', and the polar coordinates of q ' are (ρ, γ), and ρ represents mobile distance, and γ represents mobile angle, and it is round that q ', which is with pole,
The heart, ρ are any point in radius and circular trace with 4 notches, with reference to site e, by remaining site of set A it is mobile with
E identical angle and distance in site in the present embodiment, directly in photoshop software, chooses all sites of set A, together
When be modulated, it is easy to operate accurate；Screening parameter includes screen angle and screen frequency, remembers that the screen angle of mother matrix is θ, note
The screen frequency is l；
B, the α value obtained according to step 1, the value of the α of the present embodiment are 0.15, are belonged toRange, θ is
0 °, equation of locus is：
Site e is moved to any point on aforementioned equation of locus, in the present embodiment 1, q's ' after preferably site e is mobile
Polar coordinates areMeanwhile remaining site of set A is mobile similarly away from walk-off angle with jet nit point e
Degree, after completing phase-modulation, at this point, anti-counterfeiting information is already embedded in host image；Obtain carrying the mother matrix half of anti-counterfeiting information
It is carried out image with 3 width pair version half-tone pictures and synthesized by tone illustration, new image two in photoshop, the length and width of image two
Identical with the length and width of host image, the input resolution ratio of image two is 2400dpi, and background content is white, and color mode is
Mother matrix half-tone picture and 3 width pair version half-tone pictures are copied into corresponding Color Channel, referring to fig. 2, are taken by CMKY mode
Host image half-tone picture with anti-counterfeiting information completes hiding for anti-counterfeiting information；
Step 5：The identification of anti-counterfeiting information
Knowing method for distinguishing is：
(1), production identification grating：In photoshop, the identification grating of digital document form is prepared, identifies grating
Area is greater than the area of hidden area, and identification grating is parallel to each other and is alternatively arranged by the identical blackstreak of length and transparent stripe
Composition, the width of blackstreak are T1, the width of transparent stripe is T2；
T1Determination method be：To form Moire fringe, T is designed1=2r, r are site radius, so that during the extraction process,
It presents a contrast and anti-counterfeiting information is shown, and becauseTherefore T1=2r is equivalent to：To
Further,The width of identification grating blackstreak and transparent stripe has been determined with this；
(2), it will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation identification grating makes
It must identify that grating is parallel with horizontal line, then move up and down identification grating, until the site of set A and identification grating form and have
There is the anti-counterfeiting information of powerful contrast, to complete the identification of anti-counterfeiting information, referring to Fig. 3, obtains the identification light for extracting anti-counterfeiting information
The stacking chart of grid and host image half-tone picture；In the present embodiment,β=0 °.
Furtherly, in step 4, further include will be embedded with carry anti-counterfeiting information host image half-tone picture printing it is defeated
Out, before the output for printing, setting identification label, identification are labeled as cross-shaped structure, cross knot on host image half-tone picture
Angle between one side and horizontal line of structure is the β, then controls exposure output into printing plate by output equipment, or correspond to
Film is made and shines seal carving version again, 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 step 5
Grid are covered on host image material object, grating in kind are rotated according to identifying to mark, so that the blackstreak of grating in kind or saturating
Bright fringe is parallel with horizontal line, then moves left and right grating in kind, until observing anti-counterfeiting information, completes identification.
Embodiment 2
Referring to fig. 4,5 and 6, on the basis of embodiment 1, embodiment 2 the difference is that：(1), host image is not
Together；(2), anti-counterfeiting information is text；(3), 0.1 α.
Embodiment 3
Referring to Fig. 7,8 and 9, 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), the polar coordinates of the q ' after 0.25 α, preferably site e are mobile are
Comparative example
In this comparative example, control group 1,2 and 3 is set, carries out compareing test with embodiment 1,2 and 3 respectively：
(1), control group 1：Compared with Example 1, the difference is that the polar coordinates for the q ' being only that after site e movement are
(90 °), that is, the prior art is used, moving direction is perpendicular to screen angle, and moving distance is the one of two site distances
Half；It obtains after accurately extracting anti-counterfeiting information, identifies the stacking chart of grating and host image half-tone picture；
(2), control group 2：Compared with Example 2, the difference is that the polar coordinates for the q ' being only that after site e movement are
(90 °), that is, the prior art is used, moving direction is screen angle, and moving distance is the half of two site distances；?
To after accurate extraction anti-counterfeiting information, the stacking chart of grating and host image half-tone picture is identified；
(3), control group 3：Compared with Example 3, the difference is that the polar coordinates for the q ' being only that after site e movement are
(90 °), that is, the prior art is used, moving direction is screen angle, and moving distance is two site distances
Half；It obtains after accurately extracting anti-counterfeiting information, identifies the stacking chart of grating and host image half-tone picture；
Further, in this comparative example, identity evaluation is also extracted：
Using region contrast function FiWith comentropy function algorithm Ti, the value 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 significant：
(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 the frequency that gray value k occurs in the images, N indicates the gray scale etc. of image
Grade.
Using region contrast function FiWith comentropy function algorithm TiRespectively evaluate control group 1, control group 2, control group 3,
Embodiment 1, embodiment 2, the identification grating of embodiment 3 and host image half-tone picture stacking chart (accurately extract anti-counterfeiting information
In the state of), obtained result is as shown in table 1 below：
Table 1 extracts identity evaluation result
Embodiment 1 is compared with control group 1, using identical host image and anti-counterfeiting information, the stacking chart finally obtained,
The anti-counterfeiting information that embodiment 1 can intuitively be observed very much is more significant, that is, forms stronger contrast and contrast, extracts
Performance is more preferable, referring to the data of table 1, the F of embodiment 1iAnd TiValue closer to 1, and have with the data of control group 1 larger
Gap, the extraction performance for objectively having reacted embodiment 1 are more preferable；Similarly, embodiment 2 and embodiment 3 achieve good
Effect, particularly, the comparison of embodiment 3 and control group 3, the α of the group is 0.25, that is, uses the hidden method of control group 3, can produce
Raw strong site overlap joint, therefore control group 3 in concealment and extracts the effect that can obtain not as good as embodiment 3 in performance.
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) algorithm 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, similarly to embodiment 2 and 3 using identical
Method, it is as shown in table 2 below to obtain result：
2 concealment of table evaluates 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 value of Examples 1 to 3 is all close to 1, and is all larger than 0.9, with the host image half for not doing any processing
Tone illustration is compared, and difference is very small, can preferably hide anti-counterfeiting information；WSNR is larger simultaneously, further demonstrates this hair
Bright method expands the scope of application of phase-modulation optimum point principle, also, still has the hidden effect of comparable anti-counterfeiting information
It is good, it is not easy to be detected by human eye.
In conclusion compared with prior art, being characterized in particular in place of difference of the invention：
(1), site can be generated overlapped threshold value by finding：It is found in the present invention, works as D/2=D1When, it is selected at this point, being located at site
The borderline part site in area is just in contact with the site in front of it but does not overlap, D after mobile1Equal to two neighboring site
The distance between D subtract the value of two radius r, in the case where screen frequency is certain, D1Then depend on site radius r, and net
Point radius depends on dot percentage α (i.e. the corresponding color value of pixel on channel), obtains following formula：
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 research in view of this threshold value influences site displacement method bring；
(2), the distance that site is mobile in phase-modulation is optimized
Based on difference (1), only it is less than or equal in α in the present inventionWith reference to existing site displacement method, i.e. site is moved
Dynamic distance is D/2；
When α is greater thanTo guarantee certain concealment, while guaranteeing that borderline site can do to extract identity again
It contributes out, when site moving distance S is maximum distance D1When, it extracts performance and reaches most preferably, it is specific as follows：
S=D1；
And because：
So when α is greater thanThe mobile distance in site is
(3), the direction that site is mobile in phase-modulation is optimized
In the prior art, the moving direction of phase modulation site be only along screen angle direction front and back or perpendicular to
The front and back in screen angle direction, in conjunction with moving distance, the last shift position in site is only at 4, and the present invention is directed toHidden area each site, referring to site e any in Figure 10, moveable position is a circular rail
Mark, using the central point q in home position as the center of circle of circular trace, using D/2 as the radius of circular trace, referring to Figure 11, in set A
Any site e, establish polar coordinates using the central point q of site e as pole, the position of the mobile rear center's point of site e is q ', q '
Polar coordinates be (ρ, γ), q ' is any point on polar equation ρ, and polar equation is：It is such
Move mode may insure that site phase-modulation still has good extraction performance and concealment in the case where as small as possible；
Similarly, forHidden area each site, moveable position is also a circular trace, with original net
The center of circle of point is the center of circle of circular trace, with D1For the radius of circular trace, polar equation is：
(4), the mobile direction in site is advanced optimized in conjunction with extraction performance
In the prior art, the stage is extracted in the identification of anti-counterfeiting information, designs the identification grating with the corresponding period, is covered on
On host image, identification grating accurately extracts anti-counterfeiting information under special angle, in the hiding stage of anti-counterfeiting information early period,
When the direction of site modulation is along screen angle direction, which is to modulate perpendicular to screen angle direction, site
When direction is perpendicular to screen angle direction, which is along screen angle direction；
The present invention advanced optimizes the mobile direction in site, is less than or equal to αFor, referring to Figure 12, q in figure1’、
q2’、q3’、q4’、q5’、q6’、q7’、q8' be circular trace 8 points, when the center of circle, q is moved to q1’、q4’、q6’、q7' this 4 positions
When setting, the site after movement is just tangent with the identification grating along screen angle direction, and when the center of circle, q is moved to q2’、q3’、q5’、
q8' this 4 positions when, it is mobile after site just with it is tangent perpendicular to the identification grating along screen angle direction；When site is moved
The dynamic center of circle is in q1' and q2' between, q3' and q4' between, q5' and q6' between and q7' and q8' between when, identification grating can be with
Site overlapping, is unable to reach preferable recognition effect, and therefore, the present invention excludes aforementioned 4 modulation angle；
So in conjunction with Figure 13, in the present invention, only with from q1' arrive q4’、q3' arrive q5’、q6' arrive q7' and q2' arrive q8'
There are four the circular trace of notch, the direction mobile as site and distances for tool；Solve q1’、q2’、q3’、q4’、q5’、q6’、
q7’、q8' polar coordinates：
q1' polar coordinates：Referring to Figure 14, the center of circle q and q are remembered1' line and screen angle direction (i.e. cable direction) between
Angle be Ω1, remember center of circle q1' and the line and horizontal line of center of circle q between angle be γ1, it is therefore, corresponding,Again because of γ1=Ω1-θ；It obtainsq1' pole
Coordinate is
q2' polar coordinates：Referring to Figure 15, the center of circle q and q are remembered2' line and screen angle direction (i.e. cable direction) between
Angle be Ω2, remember center of circle q2' and the line and horizontal line of center of circle q between angle be γ2, remember any two points on horizontal line
For O1And O2, remember θ1=90 ° of-θ,Again because of γ2=Ω2-θ1；It obtainsq2' polar coordinates be (-γ2), as
Similarly, note counter clockwise direction, ∠ O1qq4'=γ4, ∠ O1qq3'=γ3, ∠ O1qq5'=γ5；Note is square clockwise
To ∠ O1qq6'=γ6, ∠ O1qq7'=γ7, ∠ O1qq8'=γ8；Q can be obtained4' polar coordinates be：(γ4), i.e.,q3' polar coordinates be：(γ3), i.e.,
q5' polar coordinates be：(γ5), i.e.,q6' polar coordinates be：(-γ6),
I.e.q7' polar coordinates be：(-γ7), i.e.,
q8' polar coordinates be：(-γ8), i.e.,
Therefore, the phase modulating method referring to Figure 12 and after combining Figure 16, the present invention to optimize, the moveable set of locations in site
At the circular trace with notch at 4, the polar equation of the track is：
WhenWhen, each site in the constituency of site, its own modulated position composition with lacking everywhere
The circular trace of mouth, the radius of the circular trace areAngular range is：
(γ1≤γ≤γ4；γ3≤γ≤γ5；-γ6≤γ≤-γ7；-γ8≤γ≤-γ2)；
Obtained equation of locus is：
It is equivalent to：
Similarly, whenWhen, each site in the constituency of site, its own modulated position composition has four
Locate the circular trace of notch, the radius of the circular trace isAngular range is：
(γ1≤γ≤γ4；γ3≤γ≤γ5；-γ6≤γ≤-γ7；-γ8≤γ≤-γ2)；
Obtained equation of locus is：
It is equivalent to：
(5), the identification angle of design identification grating
According to the equation of locus that aforementioned distinctive points (4) are designed, when extracting hiding anti-counterfeiting information using identification grating, note
When accurately extracting anti-counterfeiting information, identify that the angle (acute angle) between grating and horizontal line is β：
Claims (8)
1. a kind of method of anti-counterfeiting information hiding before printed matter output, which is characterized in that include the following steps：
Step 1: selection and decomposition host image
Host image is randomly choosed, host image is the digital document being made of m*n pixel；
The image model of host image is arranged to CMYK mode, decomposes host image, make its by C-channel, the channel M, the channel Y and
Totally 4 Color Channels form K channel；
Step 2: determining the hidden area of host image and anti-counterfeiting information
There is the hidden area that anti-counterfeiting information can be set, hidden area has s*s at least one Color Channel of host image
A pixel, the Color Channel where remembering the hidden area is mother matrix, and all pixels point of hidden area is on mother matrix
Color value is all the same, is denoted as α, and α is 0.1~0.5；Remaining Color Channel is 3 secondary versions；
When that can not select the hidden area that α is 0.1~0.5, then return step one reselects host image and carries out place again
Master image is decomposed, until finding the hidden area that α is 0.1~0.5；
Step 3: host image halftone process
Screening parameter is respectively set to 4 Color Channels and carries out screening processing, obtains the mother matrix half-tone picture and 3 being made of site
Width pair version half-tone picture；
Step 4: 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 of phase-modulation is：Remember any site e in set A, polar coordinates established as pole using the central point q of site e,
The position of the mobile rear center's point of site e is q ', and the polar coordinates of q ' are (ρ, γ), and q ' is to be radius as the center of circle, ρ using pole and have
Any point in the circular trace of 4 notches, by the mobile angle and distance identical with site e in remaining site of set A, screening
Parameter includes screen angle and screen frequency, remembers that the screen angle of mother matrix is θ, θ=0 ° remembers that the screen frequency is l；
The α value obtained according to step 1, whenWhen, the radius of the circular trace with 4 notches is
Equation of locus is：
WhenWhen, the radius of the circular trace with 4 notches isEquation of locus is：
WhenWhen, the radius of the circular trace with 4 notches isEquation of locus is：
Step 5: the identification of anti-counterfeiting information
(1), production identification grating：The identification grating for preparing digital document form identifies that the area of grating is greater than hidden area
Area, identification grating is parallel to each other 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
(2), it will identify that grating is covered on the host image half-tone picture for carrying anti-counterfeiting information, rotation identification grating, so that knowing
The other angle that formed between grating and horizontal line is β, then identification grating is moved forward and backward along the direction β, until the site of set A and knowledge
Other grating forms the anti-counterfeiting information with powerful contrast, to complete the identification of anti-counterfeiting information；
After the completion of phase-modulation, the mother matrix half-tone picture for carrying anti-counterfeiting information is obtained, it is subjected to figure with 3 width pair version half-tone pictures
As synthesis, the host image half-tone picture for carrying anti-counterfeiting information is obtained, completes hiding for anti-counterfeiting information.
2. the method for anti-counterfeiting information hiding before printed matter output according to claim 1, it is characterised in that：The step
In three, screening processing adjusts screen using half in photoshop software, and screening parameter further includes output resolution ratio and site shape
Shape, when carrying out screening processing respectively to 4 Color Channels, using identical output resolution ratio, screen frequency and dot shape, 3
Any combination that the screen angle of a pair version is 15 °, 45 ° and 75 °.
3. the method for anti-counterfeiting information hiding before printed matter output according to claim 2, it is characterised in that：The site
Shape is circle, in the step 2, s < m and s < n.
4. the method for anti-counterfeiting information hiding before printed matter output according to claim 1, it is characterised in that：The β's
The method of determination is：
5. the method that optimization method information extraction stage identification grating according to claim 1 extracts performance, feature exist
In：In the step 2, screening processing adjusts screen using half in photoshop software, and screening parameter further includes that output is differentiated
Rate and dot shape, when carrying out screening processing respectively to 4 Color Channels, using identical output resolution ratio, screen frequency and
Dot shape, any combination that the screen angle of 4 Color Channels is 0 °, 18.44 °, 45 ° and 71.57 °, output resolution ratio are
2400dpi, screen frequency 96lpi.
6. the method for anti-counterfeiting information hiding before printed matter output according to claim 1, it is characterised in that：The step
Further include that will be embedded with the host image half-tone picture the output for printing for carrying anti-counterfeiting information in four, before the output for printing, schemes in host
As setting identification label on half-tone picture, identification is labeled as cross-shaped structure, between one side and horizontal line of cross-shaped structure
Angle is the β, then controls exposure output by output equipment and film is made and shines seal carving version again at printing plate, or correspondence,
The host image for obtaining carrying anti-counterfeiting information is in kind.
7. the method for anti-counterfeiting information hiding before printed matter output according to claim 6, it is characterised in that：The step
In five, further includes that the identification grating of digital document form is prepared into corresponding grating in kind, grating in kind is covered on host
On image material object, grating in kind is rotated according to identification label, so that the blackstreak or transparent stripe and level of grating in kind
The angle of line is the β, is then moved forward and backward grating in kind along the direction β, until observing anti-counterfeiting information, completes identification.
8. the method for anti-counterfeiting information hiding before printed matter output according to claim 1, it is characterised in that：The step
In four, the method for building up in site constituency is：
(1), in photoshop software, new image one, the length and width of image one and the length and width of host image are identical, 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.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114298251A (en) * | 2021-12-27 | 2022-04-08 | 航天信息股份有限公司 | Anti-counterfeiting image printing method and device and related equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114298251A (en) * | 2021-12-27 | 2022-04-08 | 航天信息股份有限公司 | Anti-counterfeiting image printing method and device and related equipment |
| CN114298251B (en) * | 2021-12-27 | 2024-04-23 | 航天信息股份有限公司 | Anti-counterfeiting image printing method and device and related equipment |
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