CN108765507A - The hidden method of anti-counterfeiting information of the one kind based on 20 ~ 50% dot percentages - Google Patents
The hidden method of anti-counterfeiting information of the one kind based on 20 ~ 50% dot percentages Download PDFInfo
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- CN108765507A CN108765507A CN201810512559.0A CN201810512559A CN108765507A CN 108765507 A CN108765507 A CN 108765507A CN 201810512559 A CN201810512559 A CN 201810512559A CN 108765507 A CN108765507 A CN 108765507A
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- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T9/00—Image coding
Abstract
The invention discloses a kind of hidden methods of the anti-counterfeiting information based on 20~50% dot percentages, include the following steps：(1), prepare original copy and pretreatment；(2), site displacement；(3), dot percentage classification improves；(4), image synthesizes.Displacement algorithm and dot percentage algorithm are designed in the encryption section that the present invention is 0.2~0.5 for dot percentage, improve the concealment and extraction identity of anti-counterfeiting information, reduce operation difficulty.
Description
Technical field
The invention belongs to grating field of anti-counterfeit technology, and in particular to a kind of anti-fake letter based on 20~50% dot percentages
The hidden method of breath.
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 displacement adjusts method 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.
Displacement adjust method algorithmic formula be：Wherein, X and Y indicate respectively site laterally and
Longitudinal displacement, D represent the distance between two neighboring site on screening direction, i.e. the practical distance moved in site is D/2,
Unit is mm, and since screen frequency certainly will be arranged in image halftoning process, D is a known numeric value,
Although displacement adjusts method using very universal, there is also following deficiencies：
(1), the stage is hidden in anti-counterfeiting information, when dot percentage is more than 20%, especially 20~50% site hundred
Divide ratio, adjusting method using displacement will produce site overlap joint problem, cause visual perception, concealment relatively low；
(2), the stage is extracted in anti-counterfeiting information, makes the digital raster used, do not reach best in extraction performance；
(3), heavy workload and cumbersome.
Invention content
The object of the present invention is to provide a kind of hidden method of the anti-counterfeiting information based on 20~50% dot percentages, for
The encryption section that dot percentage is 0.2~0.5 designs displacement algorithm and dot percentage algorithm, improves the hidden of anti-counterfeiting information
Covering property and extraction identity, reduce operation difficulty.
The present invention provides the following technical solutions：A kind of anti-counterfeiting information based on 20~50% dot percentages is hidden
Method, which is characterized in that include the following steps：
(1), prepare original copy and pretreatment
Prepare original copy, original copy is rectangular configuration and is the digital document that Color Channel synthesizes, and Color Channel is led to by C-channel, M
Totally 4 channels form for road, the channels Y and K channel, and the value of the dot percentage on each channel is read in image processing software,
At least one channel has the identical region of dot percentage in Color Channel, remembers the value of the dot percentage in the region
It is 0.2~0.5 for α, α；
Select any one channel with the identical region of dot percentage as encrypted tunnel, remaining channel is 3
Common passageway is respectively set screening parameter to 4 channels and carries out screening processing, obtains the encrypted tunnel halftoning being made of site
Figure and 3 width Common passageway half-tone pictures；
Screening processing adjusts screen using half, and screening parameter includes output resolution ratio, screen frequency and dot shape, right
When 4 channels carry out screening processing respectively, using identical output resolution ratio, screen frequency and dot shape；Dot shape is equal
For circle；
(2), site displacement
Remember that the screen frequency is l, screening parameter further includes screen angle, and 4 channels correspond to 4 different screenings respectively
Angle remembers that the screen angle of the encrypted tunnel is θ；Remember corresponding identical with dot percentage in encrypted tunnel half-tone picture
Region is encryption section；Selection needs hiding anti-counterfeiting information, and site is established in encryption section according to the profile of anti-counterfeiting information
Constituency is remembered that the site in the constituency of site is set A, the site of set A is carried out displacement, indicated laterally and vertical respectively using X and Y
To displacement, corresponding α values are substituted into displacement algorithm, displacement algorithm is：
(3), dot percentage classification improves
The collection for being located at the site on the selection border of site in the site of note set A is combined into B, B ∈ A, in note encrypted tunnel
The collection of site outside the constituency of site and near site constituency is combined into G, and the profile sum aggregate that the site of the set G is formed is combined into
The profile that the site of B is formed is adapted；When site carries out displacement, the movement shape of the site of set B relative to the site of set G
State includes far from movement, close movement and parallel motion；The collection of the site close to movement is combined into B1, the separate movement
The collection of site is combined into B2, after the completion of the displacement of site, to set B1Site carry out dot percentage improvement, improved site hundred
Divide than being α1'：
Then to set B2Site carry out dot percentage improvement, improved dot percentage be α2'：
Set B2After completing dot percentage improvement, set B is replicated2, obtain set B2', and will set B2' in site
It is moved to set B2Between the corresponding sites set G, the encrypted tunnel half-tone picture after being encoded；
(4), image synthesizes
By after coding encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures synthesize, obtain carrying anti-fake
The original copy half-tone picture of information completes hiding for anti-counterfeiting information.
As further describing for above-mentioned technical proposal：
The screen angle includes 0 °, 18.44 °, 45 ° and 71.57 °, and θ is 0 °, and the screen angle of 3 Common passageways is
18.44 °, 45 ° and 71.57 arbitrary combination.
As further describing for above-mentioned technical proposal：
The original copy is the digital document opened using photoshop softwares, and the screening processing is using in photoshop
Half adjust the screen, the method that each channel carries out screening processing to be：Channel is chosen, channel is converted into bitmap, when conversion is arranged
Then the output resolution ratio adjusts screen to the processing of channel screening using half, the screen frequency is 50~200lpi, output point
Resolution is the integral multiple of screen frequency.
As further describing for above-mentioned technical proposal：
The screen frequency is 96lpi, output resolution ratio 2400dpi.
As further describing for above-mentioned technical proposal：
The anti-counterfeiting information is word and/or figure.
As further describing for above-mentioned technical proposal：
The anti-counterfeiting information is word, and the site displacement is completed using photoshop softwares, described to establish site constituency
Method be：
(1), new image one in photoshop, the length and width of image one are identical with the length and width of original copy, the resolution of image one
Rate is identical with the output resolution ratio, and background content is white, " figure layer 0 " is obtained in figure layer channel, by the encrypted tunnel
Half-tone picture is copied into image one, obtains " 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), the Type tool is selected, anti-counterfeiting information is inputted, obtains " figure layer 3 ", choose " figure layer 3 ", selected using magic wand menu
Middle anti-counterfeiting information, obtains site constituency, and setting " figure layer 3 " is invisible.
As further describing for above-mentioned technical proposal：
The anti-counterfeiting information is figure, and the site displacement is completed using photoshop softwares, described to establish site constituency
Method be：
(1), new image one in photoshop, the length and width of image one are identical with the length and width of original copy, the resolution of image one
Rate is identical with the output resolution ratio, and background content is white, " figure layer 0 " is obtained in figure layer channel, by the encrypted tunnel
Half-tone picture is copied into image one, obtains " 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), it is placed in anti-counterfeiting information, " figure layer 3 " is obtained, chooses " figure layer 3 ", choose anti-counterfeiting information using magic wand menu, obtain
To site constituency, it is invisible that " figure layer 3 " is set.
As further describing for above-mentioned technical proposal：
Described image synthetic method is：
New image two in photoshop, the length and width of image two are identical with the length and width of original copy, the resolution ratio of image two and
The output resolution ratio is identical, and background content is white, and color mode is CMKY patterns, by the encrypted tunnel after the coding half
Tone illustration and 3 width Common passageway half-tone pictures be copied into corresponding Color Channel to get.
As further describing for above-mentioned technical proposal：
Further include analog codec after described image synthesis：
Prepare analog codec grating, decoding grating is mutually parallel interval row by the identical blackstreak of length and transparent stripe
The width of row composition, blackstreak is T1, the width of transparent stripe is T2,
As further describing for above-mentioned technical proposal：
The T1Computational methods be：
Decoding grating is covered on original copy half-tone picture, rotation and mobile decoding grating carry out analog codec, until seeing
Observe anti-counterfeiting information.
Beneficial effects of the present invention：Displacement algorithm and net are designed in the encryption section for being 0.2~0.5 for dot percentage
Point percentage algorithm improves the concealment and extraction identity of anti-counterfeiting information, reduces operation difficulty, specific as follows：
1, in anti-counterfeiting information coding stage, the low-frequency filter characteristics based on human eye vision are carrying out am screening to original copy
After processing, changes the dot location and dot percentage of regional area in anti-pseudo-channel, anti-counterfeiting information is embedded into original image
Among, achieve the purpose that anti-counterfeiting information is hidden；Advantage compared with prior art is：
(1), when the percentage of the site in set A is 0.2≤α≤0.5, D is moved into set A wholes site1Away from
From to ensure to make anti-counterfeiting information display in the extraction stage, at this time except set B in set A1With set B2Site in addition
It is identical in other conditions in extraction performance if it is nonsensical still to move D/2, mobile D1Effect significantly
It is better than and moves the effect of D/2, displacement is unified into the site in set A in the present invention, it is possible to reduce prodigious workload, then
To set B1With set B2Dot percentage be improved, be equally used for improve concealment；
(2), the coding method of the present embodiment can improve concealment and extraction identity, and also reduce work simultaneously
Measure, specific aim is stronger, meanwhile, operationally, advanced line position transposition section improves dot percentage again, it is possible to reduce workload and
Operation difficulty is reduced, the generation of error is effectively avoided, meanwhile, tribute is made in borderline site to improving concealment and identity
It offers；
2, in anti-counterfeiting information decoding stage, it is based on the anti-fake principle of moir patterns grating, it, will using the optical characteristics of transmission grating
Half tone image and the grating of design to match after screening are superimposed, and the longitudinal Moire fringe for forming period infinity is existing
As to show anti-counterfeiting information, achieving the purpose that anti-counterfeiting information extracts；The present invention point research decodes grating in the prior art
Deficiency carries out the improvement of overall scientific, in the prior art, to form Moire fringe, in the decoding grating of design, T1=2r, but
The anti-counterfeiting information that identification is extracted in the present invention is based not only on Moire fringe, is also based on contrast comparison, is surveyed by many experiments
It takes temperature bright, when the percentage of the site in set A is 0.2≤α≤0.5, T1Width range be 2r≤T1< D1, in this model
The decoding grating being prepared in enclosing, can clearly extract anti-counterfeiting information；And becauseTherefore 2r≤T1< D1Deng
Valence in：
The present invention, which has, targetedly designs grating, and it is inclined to break traditional technology that anti-counterfeiting information can be just obtained based on moir patterns
See, the covering width of design decoding grating improves the clarity and resolution when grating decoding so that using as far as possible
When, can more aspect progress anti-counterfeiting information verification；
3, the preparation method in site constituency of the present invention is more simple accurate, is directly made on anti-pseudo-channel half tone image
Make, and be adjusted so that the site in constituency is complete site, compared to the prior art in, it is anti-fake before screening
The method in prefabricated constituency in channel, method of the invention can accurately select complete site；
4, the present invention can prefabricated extraction effect, encode anti-counterfeiting information in the picture, and make corresponding analog codec light
Grid can be extracted, prefabricated detection result before image printing output with analog codec Grating examinations anti-counterfeiting information, convenient
Hidden image is verified, there is early warning effect, convenient for subsequently using corresponding data creating material object lenticular lenses；
5, original copy of the invention can be the original copy directly made in image processing software, can also be to randomly select
Meet the original copy of the condition of step 1, the scope of application is wider, more flexible, and dot percentage is then read in image processing software
Value, different displacement algorithms is carried out according to different dot percentages and dot percentage algorithm is modified.
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 original copy in the embodiment of the present invention (color information is not shown)；
Fig. 2 is encrypted tunnel half-tone picture in the embodiment of the present invention；
Fig. 3 is the original copy half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention (color information is not shown)；
Fig. 4 is the partial schematic diagram of the encrypted tunnel half-tone picture and encryption constituency after being encoded in the embodiment of the present invention；
Fig. 5 is the anti-counterfeiting information extraction figure of analog codec in the embodiment of the present invention (color information is not shown)；
Fig. 6 is that the encrypted tunnel half-tone picture after grating is covered in the embodiment of the present invention；
Fig. 7 is the motion state analysis chart of site in the embodiment of the present invention；
In figure label for：1, site one；2, site two；3, site three；4, site four；5, site five.
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.
A kind of hidden method of the anti-counterfeiting information based on 20~50% dot percentages, which is characterized in that including walking as follows
Suddenly：
(1), prepare original copy and pretreatment
Referring to Fig. 1, prepare original copy, original copy is rectangular configuration and is the digital document that Color Channel synthesizes, and Color Channel is by C
Totally 4 channels form for channel, the channels M, the channels Y and K channel, and the dot percentage on each channel is read in photoshop
Value, at least one channel has the identical region of dot percentage in Color Channel, remembers the site percentage in the region
The value of ratio is α, and α is 0.2~0.5；The value read in the present embodiment is 0.3, and it is logical with the identical region of dot percentage
Road is C-channel；
Select C-channel as encrypted tunnel, remaining channel is 3 Common passageways, and screening parameter is respectively set to 4 channels
Screening processing is carried out, referring to Fig. 2, obtains the encrypted tunnel half-tone picture being made of site and 3 width Common passageway halftonings
Figure；
Screening processing adjusts screen using half, and screening parameter includes output resolution ratio, screen frequency and dot shape, to 4
When channel carries out screening processing respectively, using identical output resolution ratio, screen frequency and dot shape, dot shape is circle
Shape；Note screen frequency is l, and the screening parameter further includes screen angle, screen angle include 0 °, 18.44 °, 45 ° and
71.57 °, θ is 0 °, the arbitrary combination that the screen angles of 3 Common passageways is 18.44 °, 45 ° and 71.57；
(2), site displacement
Remember that the screen frequency is l, screening parameter further includes screen angle, and 4 channels correspond to 4 different screenings respectively
Angle remembers that the screen angle of the encrypted tunnel is θ；Remember corresponding identical with dot percentage in encrypted tunnel half-tone picture
Region is encryption section；Selection needs hiding anti-counterfeiting information, and site is established in encryption section according to the profile of anti-counterfeiting information
Constituency is remembered that the site in the constituency of site is set A, the site of set A is carried out displacement, indicated laterally and vertical respectively using X and Y
To displacement α=0.3 is substituted into, displacement algorithm is by displacement algorithm according to the aforementioned value α for reading dot percentage：
(3), dot percentage classification improves
The collection for being located at the site on the selection border of site in the site of note set A is combined into B, B ∈ A, in note encrypted tunnel
The collection of site outside the constituency of site and near site constituency is combined into G, and the profile sum aggregate that the site of the set G is formed is combined into
The profile that the site of B is formed is adapted；It is the analysis chart of site motion state referring to Fig. 7, Fig. 7, wherein false for ease of distinguishing
If it is grey and white site to need the site of displacement, being enclosed in the black site outside grey site can be to should be used as this
Set G in embodiment, when carrying out displacement adjusting, the site of set B includes remote relative to the motion state of the site of set G
From movement, close movement and parallel motion；The collection of the site close to movement is combined into B1, the collection of the site far from movement
It is combined into B2；It can be seen from figure 7 that when θ be 0 °, direction of displacement vertically upward, at this point, the motion state of site 1 is close
Movement, the motion state of site 22 are parallel motion, and the motion state of site 33 and site 55 is far from movement, site 44
Then without displacement；After the completion of the displacement of site, to set B1Site carry out dot percentage improvement, improved site percentage
Than for α1'：
Then to set B2Site carry out dot percentage improvement, improved dot percentage be α2'：
Set B2After completing dot percentage improvement, set B is replicated2, obtain set B2', and will set B2' in site
It is moved to set B2Between the corresponding sites set G, the encrypted tunnel half-tone picture after being encoded can be seen referring to Fig. 4
Go out, close to the site that the site of dotted line frame is parallel motion, has only carried out displacement, do not carried out dot percentage improvement；
(4), image synthesizes
Referring to Fig. 3, by after coding encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures synthesize, obtain
The original copy half-tone picture for carrying anti-counterfeiting information completes hiding for anti-counterfeiting information.
In the present embodiment, preferably screen frequency is 96lpi, and output resolution ratio 2400dpi, output resolution ratio is screening line
Several integral multiples, maximum is amplified in photoshop by figure layer, can clearly see that the length of side of each mesh tune unit is
25 small grid composition, the length T of the second rectangle1+T2The as length of side of mesh tune unit, also between as two neighboring site
Distance therefore, make decode linear grating in, it is only necessary to according to T1Evaluation and combine small grid, for further serving as
To calibration function, the error of operation is reduced, reduces a large amount of workload.
Wherein,
The original copy is the digital document opened using photoshop softwares, and the screening processing is using in photoshop
Half adjust the screen, the method that each channel carries out screening processing to be：Channel is chosen, channel is converted into bitmap, when conversion is arranged
Then the output resolution ratio adjusts screen to the processing of channel screening using half, the screen frequency is 50~200lpi, output point
Resolution is the integral multiple of screen frequency.In the present embodiment preferably, screen frequency 96lpi, output resolution ratio 2400dpi.
Wherein,
The anti-counterfeiting information of the present embodiment is word, and the site displacement is completed using photoshop softwares, described to establish net
Point constituency method be：
(1), new image one in photoshop, the length and width of image one are identical with the length and width of original copy, the resolution of image one
Rate is identical with the output resolution ratio, and background content is white, " figure layer 0 " is obtained in figure layer channel, by the encrypted tunnel
Half-tone picture is copied into image one, obtains " 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), the Type tool is selected, anti-counterfeiting information is inputted, obtains " figure layer 3 ", choose " figure layer 3 ", selected using magic wand menu
Middle anti-counterfeiting information obtains site constituency, and setting " figure layer 3 " is invisible, chooses " figure layer 1 " to delete the site in the constituency of site, so
After choose " figure layer 2 ", replicate paste site constituency in site, obtain " figure layer 4 ", then delete " figure layer 2 " and " figure layer 3 ",
So that " figure layer 4 ", " figure layer 1 " and " figure layer 0 " is sequentially arranged in figure layer window, the site in " figure layer 4 " is to need at this time
The site of adjustment.In addition, anti-counterfeiting information can also be preferably figure.
Wherein,
The present embodiment image synthetic method is：New image two in photoshop, the length and width of image two and original copy
Length and width are identical, and the resolution ratio of image two is identical with the output resolution ratio, and background content is white, and color mode is CMKY moulds
Formula, by after the coding encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures be copied into corresponding Color Channel,
To obtain the final product.
Wherein,
Further include analog codec after described image synthesis referring to Fig. 5 and Fig. 6：
Prepare analog codec grating, decoding grating is mutually parallel interval row by the identical blackstreak of length and transparent stripe
The width of row composition, blackstreak is T1, the width of transparent stripe is T2,T1Computational methods be：
Decoding grating is covered on original copy half-tone picture, rotation and mobile decoding grating carry out analog codec, until seeing
Observe anti-counterfeiting information.
Wherein,
Decoding linear grating production method be：
(1), photoshop softwares are opened, figure layer X is created, background colour is set as transparent (no background colour), is then built again
Figure layer on the first rectangle of a length and width particular value is drawn with the rectangle tool, Fill Color is (excellent in the rectangle frame then finished again
It is selected as 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 do
Good pattern saves as " pattern 0 "；
(2) and then the X that deletes layer it builds, then again a new figure layer and is named as figure layer Z, the size of figure layer Z is to decode
The size of linear grating, resolution ratio is identical with the output resolution ratio, then utilizes " pattern 0 " the Photoshop Z preserved, filling
The decoding linear grating for detecting anti-counterfeiting information is formed afterwards.
Wherein,
The length of first rectangle is T1, the length of the second rectangle is T1+T2, the length of the first rectangle and the second rectangle
Length can be measured with scale, other conventional methods can also be used, so that the width of obtained blackstreak meets T1Meter
The numerical value that calculation method obtains.
Comparative example
On the basis of embodiment, tested using control group 1 and control group 2 in comparative example：
(1), control group 1 the difference is that：Displacement adjusting is only carried out, is improved without dot percentage, displacement is calculated
Method is：
(2), control group 2 the difference is that：Method is adjusted using existing displacement, and using identical with the present embodiment
Dot percentage improved method, displacement algorithm are：
By in embodiment encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures merge, obtain being not embedded into anti-
The original copy half-tone picture of fake information is evaluated using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio) and is not embedded into respectively
The similarity of the original copy half-tone picture of anti-counterfeiting information and the original copy half-tone picture of carrying anti-counterfeiting information between the two；
By in control group 1 encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures merge, obtain being not embedded into anti-
The original copy half-tone picture of fake information is evaluated using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio) and is not embedded into respectively
The similarity of the original copy half-tone picture of anti-counterfeiting information and the original copy half-tone picture of carrying anti-counterfeiting information between the two；
By in control group 2 encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures merge, obtain being not embedded into anti-
The original copy half-tone picture of fake information is evaluated using SSIM (structural similarity) algorithms and WSNR (weighted signal-to-noise ratio) and is not embedded into respectively
The similarity of the original copy half-tone picture of anti-counterfeiting information and the original copy half-tone picture of carrying anti-counterfeiting information between the two, obtains to indirect
To the concealed evaluation result of hiding information；As shown in table 1 below：
1 similarity evaluation result of table
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 are closer 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.
In conclusion in anti-counterfeiting information coding stage, the present invention is based on displacement most traditional in grating anti-counterfeit field adjustings
Method, analysis conventional displacement adjusts the deficiency of method, carries out the improvement of overall scientific, specific as follows：
1, in the prior art, displacement adjusts method to realize Moire effect, it is contemplated that and all sites carry out identical displacement,
But set B1In site, practical movably distance is the distance between two site closest approaches D1, in the existing of this field
In technology, there has been no the movable distances to boundary node to carry out relevant further investigation, some few are also limited to shallow-layer
Subjective judgement and theoretical foundation on.Method is adjusted according to displacement, the distance of all site movements is D/2, is found in the present embodiment,
Work 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 at early period halftoning
Screening parameter can be set, therefore screen frequency is datum, screen frequency determines the distance between two neighboring site D in reason
With the length of side D of a mesh tune unit2, D=D2, in the case where screen frequency is certain, D1Then depend on site radius r, and net
Point radius depends on dot percentage α, the distance between other two site closest approach D1Equal between two neighboring site
Distance D subtracts the value of two radius r, obtains following formula：
Therefore, when D/2 is equal to D1When,Photoshop softwares to be all made of because of the prior art hidden into row information again
It hides,It is the distance between two site closest approaches D in the ideal situation1It is exactly equal to best displacement distance D/2, it is practical
It in operation, is influenced by screen frequency, dot shape is not ideal circle, therefore round numbers obtains 0.2, i.e. the present invention is ground
In the image-region for studying carefully 0.2~0.5 dot percentage, the method for anti-counterfeiting information is hidden；
2, when α >=0.2, when moving site according to traditional bit transposition section method (the mobile D/2 on screening direction), set B1
In site can be overlapped with the site in front of its moving direction, site overlap joint can cause anti-counterfeiting information concealment very big negative
Face effect, clearly, the especially site of lap-joint or borderline site can make anti-fake the visual perception of lap-joint
The profile of information is just perceived by the human eye before extraction, and antiforge function is caused to fail；
To ensure certain concealment, while ensureing set B again1Can be that extraction identity contributes, site is practical
Moveable maximum distance is D1, i.e. the present invention will all sites set A mobile D on screen angle direction1, specific as follows：
And because：
So site is as follows in horizontal and vertical displacement algorithm in set A：
In conjunction with aforementioned, in anti-counterfeiting information coding stage, the method for the present embodiment is：The α values for reading encryption section, will answer area
Site in domain carries out displacement according to aforementioned displacements algorithm, carries out following percentage improvement after displacement again, adding after being encoded
Close channel half-tone picture, it is prefabricated improved new site that dot percentage, which improves specific operating method, which has new
Dot percentage, in photoshop erasing need improved site, new site is then added at corresponding position；
3, in anti-counterfeiting information decoding stage, the present invention point research decodes the deficiency of grating, carries out comprehensive section in the prior art
Improvement, in the prior art, to form Moire fringe, in the decoding grating of design, T1=2r, but identification is extracted in the present invention
Anti-counterfeiting information be based not only on Moire fringe, be also based on contrast comparison, by many experiments test show when in set A
Site percentage be 0.2≤α≤0.5 when, T1Width range be 2r≤T1< D1, the solution that is prepared within this range
Code grating, can clearly extract anti-counterfeiting information；And becauseTherefore 2r≤T1< D1It is equivalent to：
The present invention, which has, targetedly designs grating, and it is inclined to break traditional technology that anti-counterfeiting information can be just obtained based on moir patterns
See, the covering width of design decoding grating improves the clarity and resolution when grating decoding so that using as far as possible
When, can more aspect progress anti-counterfeiting information verification.
Claims (10)
1. a kind of hidden method of the anti-counterfeiting information based on 20~50% dot percentages, which is characterized in that include the following steps：
(1), prepare original copy and pretreatment
Prepare original copy, original copy is rectangular configuration and is the digital document that Color Channel synthesizes, and Color Channel is by C-channel, the channels M, Y
Totally 4 channels form for channel and K channel, and the value of the dot percentage on each channel, color are read in image processing software
At least one channel has the identical region of dot percentage in channel, remembers that the value of the dot percentage in the region is α,
α is 0.2~0.5；
Select any one channel with the identical region of dot percentage as encrypted tunnel, remaining channel is 3 common
Channel is respectively set screening parameter to 4 channels and carries out screening processing, obtain the encrypted tunnel half-tone picture being made of site and
3 width Common passageway half-tone pictures；
The screening processing adjusts screen using half, and screening parameter includes output resolution ratio, screen frequency and dot shape, to 4
When channel carries out screening processing respectively, using identical output resolution ratio, screen frequency and dot shape；Dot shape is circle
Shape；
(2), site displacement
Remember that the screen frequency is l, screening parameter further includes screen angle, and 4 channels correspond to 4 different screening angles respectively
Degree remembers that the screen angle of the encrypted tunnel is θ；Remember corresponding with the identical area of dot percentage in encrypted tunnel half-tone picture
Domain is encryption section；Selection needs hiding anti-counterfeiting information, and site choosing is established in encryption section according to the profile of anti-counterfeiting information
Area remembers that the site in the constituency of site is set A, the site of set A is carried out displacement, indicates horizontal and vertical respectively using X and Y
Displacement, corresponding α values are substituted into displacement algorithm, displacement algorithm is：
(3), dot percentage classification improves
The collection for being located at the site on the selection border of site in the site of note set A is combined into B, B ∈ A, remembers in encrypted tunnel in site
The collection of site outside constituency and near site constituency is combined into G, and the profile sum aggregate that the site of the set G is formed is combined into B's
The profile that site is formed is adapted；When site carries out displacement, the motion state of the site of set B relative to the site of set G
Including far from movement, close movement and parallel motion；The collection of the site close to movement is combined into B1, the net far from movement
The collection of point is combined into B2, after the completion of the displacement of site, to set B1Site carry out dot percentage improvement, improved site percentage
Than for α1'：
Then to set B2Site carry out dot percentage improvement, improved dot percentage be α2'：
Set B2After completing dot percentage improvement, set B is replicated2, obtain set B2', and will set B2' in site be moved to
Set B2Between the corresponding sites set G, the encrypted tunnel half-tone picture after being encoded；
(4), image synthesizes
By after coding encrypted tunnel half-tone picture and 3 width Common passageway half-tone pictures synthesize, obtain carry anti-counterfeiting information
Original copy half-tone picture, complete anti-counterfeiting information hide.
2. the hidden method of the anti-counterfeiting information according to claim 1 based on 20~50% dot percentages, feature exist
In：The screen angle includes 0 °, 18.44 °, 45 ° and 71.57 °, and θ is 0 °, the screen angles of 3 Common passageways is 18.44 °,
45 ° and 71.57 arbitrary combination.
3. the hidden method of the anti-counterfeiting information according to claim 1 based on 20~50% dot percentages, feature exist
In：The original copy is the digital document opened using photoshop softwares, and the screening processing is using half in photoshop
Tune screen, the method that each channel carries out screening processing are：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 50~200lpi, output resolution ratio
For the integral multiple of screen frequency.
4. the hidden method of the anti-counterfeiting information according to claim 3 based on 20~50% dot percentages, feature exist
In：The screen frequency is 96lpi, output resolution ratio 2400dpi.
5. the hidden method of the anti-counterfeiting information according to claim 1 based on 20~50% dot percentages, feature exist
In：The anti-counterfeiting information is word and/or figure.
6. the hidden method of the anti-counterfeiting information according to claim 5 based on 20~50% dot percentages, feature exist
In：The anti-counterfeiting information is word, and the site displacement is completed using photoshop softwares, the side for establishing site constituency
Method is：
(1), new image one in photoshop, the length and width of image one are identical with the length and width of original copy, the resolution ratio of image one and
The output resolution ratio is identical, and background content is white, " figure layer 0 " is obtained in figure layer channel, by half color of the encrypted tunnel
It changes the line map 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 " is sequentially arranged in figure layer window；
(2), the Type tool is selected, anti-counterfeiting information is inputted, obtains " figure layer 3 ", choose " figure layer 3 ", chosen using magic wand menu anti-
Fake information, obtains site constituency, and setting " figure layer 3 " is invisible.
7. the hidden method of the anti-counterfeiting information according to claim 5 based on 20~50% dot percentages, feature exist
In：The anti-counterfeiting information is figure, and the site displacement is completed using photoshop softwares, the side for establishing site constituency
Method is：
(1), new image one in photoshop, the length and width of image one are identical with the length and width of original copy, the resolution ratio of image one and
The output resolution ratio is identical, and background content is white, " figure layer 0 " is obtained in figure layer channel, by half color of the encrypted tunnel
It changes the line map 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 " is sequentially arranged in figure layer window；
(2), it is placed in anti-counterfeiting information, " figure layer 3 " is obtained, chooses " figure layer 3 ", choose anti-counterfeiting information using magic wand menu, obtain net
Point constituency, setting " figure layer 3 " are invisible.
8. the hidden method of the anti-counterfeiting information according to claim 1 based on 20~50% dot percentages, feature exist
In：Described image synthetic method is：
New image two in photoshop, the length and width of image two are identical with the length and width of original copy, the resolution ratio of image two and described
Output resolution ratio is identical, and background content is white, and color mode is CMKY patterns, by the encrypted tunnel halftoning after the coding
Figure and 3 width Common passageway half-tone pictures be copied into corresponding Color Channel to get.
9. the hidden method of the anti-counterfeiting information according to claim 1 based on 20~50% dot percentages, feature exist
In：Further include analog codec after described image synthesis：
Analog codec grating is prepared, decoding grating is mutually parallel by the identical blackstreak of length and transparent stripe and is alternatively arranged group
At the width of blackstreak is T1, the width of transparent stripe is T2,
10. the hidden method of the anti-counterfeiting information according to claim 9 based on 20~50% dot percentages, feature exist
In：The T1Computational methods be：
Decoding grating is covered on original copy half-tone picture, rotation and mobile decoding grating carry out analog codec, until observing
Anti-counterfeiting information.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109572270A (en) * | 2018-12-06 | 2019-04-05 | 南京林业大学 | A kind of half-tone information dual anti-counterfeiting method of micro-structure site |
| CN111583090A (en) * | 2020-05-14 | 2020-08-25 | 陕西科技大学 | Hiding and displaying method based on half-tone image hidden information |
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| US20060170974A1 (en) * | 2005-01-28 | 2006-08-03 | Hsi-Chun Wang | Method of watermark with hybrid halftone dots |
| CN103996166A (en) * | 2014-06-05 | 2014-08-20 | 上海理工大学 | Holographic anti-counterfeiting algorithm based on shape of screen dot |
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2018
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US20060170974A1 (en) * | 2005-01-28 | 2006-08-03 | Hsi-Chun Wang | Method of watermark with hybrid halftone dots |
| CN103996166A (en) * | 2014-06-05 | 2014-08-20 | 上海理工大学 | Holographic anti-counterfeiting algorithm based on shape of screen dot |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109572270A (en) * | 2018-12-06 | 2019-04-05 | 南京林业大学 | A kind of half-tone information dual anti-counterfeiting method of micro-structure site |
| CN109572270B (en) * | 2018-12-06 | 2020-12-01 | 南京林业大学 | Halftone information double anti-counterfeiting method of microstructure dots |
| CN111583090A (en) * | 2020-05-14 | 2020-08-25 | 陕西科技大学 | Hiding and displaying method based on half-tone image hidden information |
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Application publication date: 20181106 |