CN108881661A - A kind of hidden method of improved moir patterns grating anti-counterfeiting information - Google Patents
A kind of hidden method of improved moir patterns grating anti-counterfeiting information Download PDFInfo
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- CN108881661A CN108881661A CN201810545634.3A CN201810545634A CN108881661A CN 108881661 A CN108881661 A CN 108881661A CN 201810545634 A CN201810545634 A CN 201810545634A CN 108881661 A CN108881661 A CN 108881661A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
- H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
- H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
- H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
- H04N1/32203—Spatial or amplitude domain methods
- H04N1/32256—Spatial or amplitude domain methods in halftone data
Abstract
The invention discloses a kind of hidden methods of improved moir patterns grating anti-counterfeiting information, include the following steps：(1), prepare original copy and pretreatment；(2), site is displaced；(3), dot percentage improves；(4), image synthesizes；(5), anti-counterfeiting information extracts.Microcosmic processing is carried out to the site of original copy Screening Image, breaks technology prejudice, improve coding concealment and extracts identity, reduces operation difficulty.
Description
Technical field
The invention belongs to grating field of anti-counterfeit technology, and in particular to a kind of improved moir patterns grating anti-counterfeiting information is hidden
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 displacement adjusting method, is completed by the position of changing section site during grating is anti-fake, 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.
Displacement adjusting method algorithmic formula be：Wherein, X and Y respectively indicate 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 being displaced adjusting 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%, net can be generated using displacement adjusting method
Point overlap joint problem, causes visual perception, concealment is lower；
(2), it is extracted the stage in anti-counterfeiting information, the digital raster used does not reach best on extracting performance；
(3), heavy workload and cumbersome.
Summary of the invention
The object of the present invention is to provide the hidden methods of improved moir patterns grating anti-counterfeiting information, to original copy Screening Image
Site carries out microcosmic processing, breaks technology prejudice, improves coding concealment and extracts identity, reduces operation difficulty.
The present invention provides the following technical solutions：A kind of hidden method of improved moir patterns grating anti-counterfeiting information, packet
Include 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 channel 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
For α, and α is 0.1~0.5；
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；Remember that the screen frequency is l, screening parameter further includes screen angle, screen angle include 0 °, 18.44 °, 45 ° and
71.57 °, remember that the screen angle of the encrypted tunnel is θ, θ is 0 °, the screen angles of 3 Common passageways be 18.44 °, 45 ° and
71.57 any combination；
(2), site is displaced
Remembering to correspond in encrypted tunnel half-tone picture has the identical region of dot percentage for encryption section；Selection needs hidden
The anti-counterfeiting information of hiding establishes site constituency according to the profile of anti-counterfeiting information in encryption section, remembers that the site in the constituency of site is
The site of set A is displaced by set A, and direction of displacement is vertically upward or vertically downward shift length S, displacement algorithm
For：
(3), dot percentage improves
Remember that the collection for being located at the site on the selection border of site in the site of 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 carrying out displacement and adjusting, 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 B2Encrypted tunnel half-tone picture between the corresponding site set G, 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；
(5), anti-counterfeiting information extracts
Prepare analog codec grating, decoding grating is parallel to each other interval row by the identical blackstreak of length and transparent stripe
Column composition, the width of blackstreak are T1, the width of transparent stripe is T2,The T1Calculation method be：
Decoding grating is covered on original copy half-tone picture, rotation and mobile decoding grating carry out analog codec, until seeing
Anti-counterfeiting information is observed, the extraction of anti-counterfeiting information is completed.
It is as above-mentioned technical proposal to further describe：
The displacement algorithm is：
It is as above-mentioned technical proposal to further describe：
The T1Calculation method be：
It is as above-mentioned technical proposal to further describe：
The original copy is the digital document opened using photoshop software, and the screening processing is using in photoshop
Half adjust screen, the method that each channel carries out screening processing is：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.
It is as above-mentioned technical proposal to further describe：
The output resolution ratio is the integral multiple of screen frequency.
It is as above-mentioned technical proposal to further describe：
The screen frequency is 96lpi, output resolution ratio 2400dpi.
It is as above-mentioned technical proposal to further describe：
The anti-counterfeiting information is text and/or figure.
It is as above-mentioned technical proposal to further describe：
The anti-counterfeiting information is text, and the site displacement is completed using photoshop software, described to establish site constituency
Method be：
(1), new image one in photoshop, the length and width of image one and the length and width of original copy are identical, 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.
It is as above-mentioned technical proposal to further describe：
The anti-counterfeiting information is figure, and the site displacement is completed using photoshop software, described to establish site constituency
Method be：
(1), new image two in photoshop, the length and width of image two and the length and width of original copy are identical, the resolution of image two
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 two, 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.
It is as above-mentioned technical proposal to further describe：
Described image synthetic method is：
New image three in photoshop, the length and width of image three and the length and width of original copy are identical, the resolution ratio of image three and
The output resolution ratio is identical, and background content is white, and color mode is CMKY mode, 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.
Beneficial effects of the present invention：Microcosmic processing is carried out to the site of original copy Screening Image, breaks technology prejudice, improves and compile
Code concealment and extraction identity, reduce 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), adjusting method is displaced in order to realize Moire effect, it is contemplated that all sites carry out identical displacement, but set B1
In site, practical movably distance is the distance between two site closest approaches D1, in the state of the art,
There has been no the movable distances to boundary node to carry out relevant further investigation, and few some subjectivities for being also limited to shallow-layer are sentenced
In disconnected and theoretical basis.According to displacement adjusting method, the mobile distance in all sites is D/2, and moving direction is the side of screen angle
To (i.e. along the cable direction of formation), is found in the present invention, work as D/2=D1When, the site after moving at this time is just and before it
The site of side is in contact but does not overlap, and since screening parameter can be arranged in halftone process early period, screen frequency is known
Number, screen frequency have determined the side length D of the D and mesh tune unit in the distance between two neighboring site2, D=D2, two nets
The distance between point closest approach D1Equal to the value that the distance between two neighboring site D subtracts two radius r, in screen frequency one
In the case where fixed, D1Site radius r is then depended on, and site radius depends on dot percentage α, 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, is influenced in photoshop by output resolution ratio, dot shape is not necessarily therefore the circle of standard takes α
Integer is 0.2；It is threshold value with α=0.2；
When site mobile according to traditional bit transposition section method, set B1In site can be taken with the site in front of its moving direction
Connect, site overlap joint can cause very big counter productive to anti-counterfeiting information concealment, the visual perception of lap-joint clearly, especially
It is the site or borderline site of lap-joint, and the profile of anti-counterfeiting information can be made just to be perceived by the human eye before extraction, led
Cause antiforge function failure；Therefore, in the present invention, only when α is less than or equal to 0.2, with reference to existing displacement adjusting method, using X
Horizontal and vertical displacement is respectively indicated with Y, displacement adjusting is carried out to the site of set A,In this range
It is interior, the hiding of anti-counterfeiting information may be implemented and extract, whereinWhen, it extracts recognition performance and reaches most preferably, displacement algorithm
It can be expressed as again：
(2), (the mobile D/2 on screening direction), set as α > 0.2, site mobile according to traditional bit transposition section method
B1In site can be overlapped with the site in front of its moving direction, site overlap joint anti-counterfeiting information concealment can be caused it is very big
Counter productive, clearly, the especially site of lap-joint or borderline site can to prevent the visual perception of lap-joint
The profile of fake information is just perceived by the human eye before extraction, and antiforge function is caused to fail；
To guarantee certain concealment, while guaranteeing set B again1Can contribute to extract identity, when it is mobile away from
It is less than or equal to D from being greater than 01When, the hiding of anti-counterfeiting information may be implemented and extract, it is specific as follows：
0 < S≤D1；
And because：
So site is as follows in horizontal and vertical displacement algorithm in set A：
Show that when site is mobile be maximum distance D by many experiments test1When, it extracts performance and reaches best.
Information concealing method of the invention can improve concealment simultaneously and extract identity, and also reduce work
Amount, specific aim is stronger, meanwhile, operationally, advanced line position transposition section improves dot percentage again, is further improved site percentage
The purpose of ratio is to improve concealment, and after the displacement of site, the site far from movement can generate larger sky with the site of surrounding
Gap forms intensive dot area with the site in front of the direction of motion, if not improving site hundred so close to the site of movement
Divide ratio, so that a part of site is excessively sparse, another part site is excessively intensive, causes visual perception, in addition, of the invention changes
Workload can be reduced into method and reduces operation difficulty, effectively avoid the generation of error, meanwhile, borderline site is to raising
Concealment and identity are made contributions；
2, it is extracted the stage in anti-counterfeiting information, the present invention point research decodes the deficiency of grating in the prior art, carries out comprehensive section
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 0.1≤α≤0.2 when, T1Width range be 2r≤T1≤ S, i.e.,Within this range
The decoding grating being prepared, can clearly extract anti-counterfeiting information, not be only T1Anti-fake letter can be just extracted when=2r
Breath, and in the present embodiment, with T1Increase, the contrast grade of extraction also increases simultaneously, it is easier to identify in extraction anti-fake
Information；And becauseThereforeIt is equivalent to：
When showing 0.2 < α≤0.5 by many experiments test, the site within the scope of this is more intensive, if continued
Increase, there is no too big raising to recognition performance is extracted,When, the extraction performance of grating identification reaches best；Therefore
T1Calculation method be：
The present invention, which has, targetedly designs grating, and anti-counterfeiting information can just be obtained based on moir patterns in the prior art by breaking
Technology prejudice, the covering width of design decoding grating, clarity and resolution when raising grating decodes as far as possible, so that
In use, can more aspect progress anti-counterfeiting information verifying；
3, the preparation method in site constituency of the present invention is more simple accurate, directly makes 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 effect before image printing output with analog codec Grating examinations anti-counterfeiting information, convenient
Hidden image is verified, there is early warning effect, uses corresponding data creating material object lenticular lenses convenient for subsequent；
5, original copy of the invention can be the original copy directly made in image processing software, be also possible to randomly select
Meeting the original copy of the condition of step 1, the scope of application is wider, and it is more flexible, dot percentage is then read in image processing software
Value, different displacement algorithm and dot percentage algorithm are carried out according to different dot percentages and are modified；
6, it is 0 ° that the screen angle of encrypted tunnel, which is θ, in the present invention, can reduce the coding difficulty of hiding anti-counterfeiting information, make
The direction for obtaining site displacement is upwardly or downwardly, to operate more convenient.
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 original copy in the embodiment of the present invention 1 (color information is not shown)；
Fig. 2 is encrypted tunnel half-tone picture in the embodiment of the present invention 1；
Fig. 3 is the partial enlargement diagram of encrypted tunnel half-tone picture in Fig. 2 embodiment of the present invention 1；
Fig. 4 is the original copy half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention 1 (color information is not shown)；
Fig. 5 is decoded anti-counterfeiting information extraction figure in the embodiment of the present invention 1 (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 1；
Fig. 7 is the motion state analysis chart of site in the embodiment of the present invention；
Fig. 8 is the original copy in the embodiment of the present invention 2 (color information is not shown)；
Fig. 9 is encrypted tunnel half-tone picture in the embodiment of the present invention 2；
Figure 10 is the partial enlargement diagram of encrypted tunnel half-tone picture in Fig. 9 embodiment of the present invention 2；
Figure 11 is the original copy half-tone picture that anti-counterfeiting information is carried in the embodiment of the present invention 2 (color information is not shown)；
Figure 12 is the anti-counterfeiting information extraction figure of analog codec in the embodiment of the present invention 2 (color information is not shown)；
Figure 13 is that the encrypted tunnel half-tone picture after grating is covered in the embodiment of the present invention 2；
In figure label for：1, site one；2, site two；3, site three；4, site four；5, site five.
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 kind of hidden method of improved moir patterns grating anti-counterfeiting information, includes the following steps：
(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 channel M, the channel Y and K channel, and the site percentage on each channel is read in image processing software
The value of ratio, at least one channel has the identical region of dot percentage in Color Channel, remembers the site hundred in the region
The value for dividing ratio is α, and α is 0.1~0.5；It is read in photoshop software in the present embodiment and obtains α=0.15；And there is net
The channel in the identical region of point percentage is C-channel；
Select C-channel as encrypted tunnel, remaining channel is 3 Common passageways, and screening parameter is respectively set to 4 channels
It carries out screening processing and obtains the encrypted tunnel half-tone picture being made of site and 3 width Common passageway half-tone pictures referring to fig. 2；
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；Remember that the screen frequency is l, screening parameter further includes screen angle, screen angle include 0 °, 18.44 °, 45 ° and
71.57 °, remember that the screen angle of the encrypted tunnel is θ, θ is 0 °, the screen angles of 3 Common passageways be 18.44 °, 45 ° and
71.57 any combination；Screen frequency is 96lpi, output resolution ratio 2400dpi；
(2), site is displaced
Remembering to correspond in encrypted tunnel half-tone picture has the identical region of dot percentage for encryption section；Referring to Fig. 3, choosing
It selects and needs hiding anti-counterfeiting information, site constituency is established in encryption section according to the profile of anti-counterfeiting information, is remembered in the constituency of site
Site be set A, the site of set A is displaced, direction of displacement is vertically upward or vertically downward, shift length S,
Displacement algorithm is：
In the present embodiment, α=0.15, shift length S is preferably
(3), dot percentage improves
Remember that the collection for being located at the site on the selection border of site in the site of 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 for convenient for differentiation, vacation
If needing the site that is displaced is grey and white site, 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, α=0.15 is substituted into following algorithm, improved net
Point percentage is 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 B2Encrypted tunnel half-tone picture between the corresponding site set G, after being encoded；
(4), image synthesizes
Referring to fig. 4, 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；
(5), anti-counterfeiting information extracts
Referring to Fig. 5, analog codec grating is prepared, decoding grating is mutually flat by the identical blackstreak of length and transparent stripe
Row interval rearranges, and the width of blackstreak is T1, the width of transparent stripe is T2,The T1Calculating
Method is：
In the present embodiment, α=0.15, preferably
Decoding grating is covered on original copy half-tone picture, rotation and mobile decoding grating carry out analog codec, until seeing
Anti-counterfeiting information is observed, the extraction of anti-counterfeiting information is completed, referring to Fig. 5 and Fig. 6 is combined, under the action of decoding grating, it can be seen that
Anti-counterfeiting information can be displayed clearly.
Wherein,
Decoding linear grating production method be：
(1), photoshop software is 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 greater than the first rectangle is drawn in the same way,
And it covers 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), then delete layer X, then builds a new figure layer again and be named as figure layer Z, and the size of figure layer Z is to decode
The size of linear grating, resolution ratio is identical with the output resolution ratio, then utilizes " pattern 0 " the Photoshop Z saved, 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.
Wherein,
The original copy is the digital document opened using photoshop software, and the screening processing is using in photoshop
Half adjust screen, the method that each channel carries out screening processing is：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.
Wherein,
The anti-counterfeiting information is text, and the site displacement is completed using photoshop software, described to establish site constituency
Method be：
(1), new image one in photoshop, the length and width of image one and the length and width of original copy are identical, 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.
Wherein,
Described image synthetic method is：
New image three in photoshop, the length and width of image three and the length and width of original copy are identical, the resolution ratio of image three and
The output resolution ratio is identical, and background content is white, and color mode is CMKY mode, 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.
By in embodiment 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 respectively using SSIM (structural similarity) algorithm and WSNR (weighted signal-to-noise ratio) and is not embedded into
The original copy half-tone picture of anti-counterfeiting information and the similarity of the original copy half-tone picture of anti-counterfeiting information between the two is carried, thus indirect
To the concealed evaluation result of hiding information, as shown in table 1 below：
1 embodiment of table, 1 similarity evaluation result
Wherein, the value of SSIM is bigger closer to the value of 1 or WSNR, and the similarity for representing two images is bigger, by upper
Table 1 is stated it is found that the SSIM value of embodiment 1 is close to 1, and WSNR is larger, therefore method of the invention, concealment effect is good, no
Easily it is detected by human eye.
Embodiment 2
On the basis of embodiment 1, embodiment 2 the difference from embodiment 1 is that：(1), different original copys is chosen, is read
α value be 0.3；(2), anti-counterfeiting information is figure, and the site displacement is completed using photoshop software, described to establish site
The method in constituency is：
(1), new image two in photoshop, the length and width of image two and the length and width of original copy are identical, the resolution of image two
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 two, 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.
By in embodiment 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 respectively using SSIM (structural similarity) algorithm and WSNR (weighted signal-to-noise ratio) and is not embedded into
The original copy half-tone picture of anti-counterfeiting information and the similarity of the original copy half-tone picture of anti-counterfeiting information between the two is carried, thus indirect
To the concealed evaluation result of hiding information, as shown in table 2 below：
2 embodiment of table, 2 similarity evaluation result
Wherein, the value of SSIM is bigger closer to the value of 1 or WSNR, and the similarity for representing two images is bigger, by upper
Table 2 is stated it is found that the SSIM value of embodiment 2 is close to 1, and WSNR is larger, therefore method of the invention, concealment effect is good, no
Easily it is detected by human eye.
In conclusion the present invention is based on the displacements in grating anti-counterfeit field to adjust method, analysis in anti-counterfeiting information coding stage
It is displaced the deficiency of adjusting method, carries out the improvement of overall scientific, it is specific as follows：
1, it in actual operation, tests and finds by many experiments, when dot percentage is less than 0.1, anti-counterfeiting information
Concealment is very good, but it is very poor to extract recognition performance；When dot percentage is greater than 0.5, the extraction identity of anti-counterfeiting information
Can preferably, but concealment is weaker, to reach best concealment and extractability, only between 0.1~0.5 in the present invention
Dot percentage；In addition, in actual operation, when dot percentage reaches 0.5, using the halftoning after photoshop screening
In figure (dot shape is circle), two neighboring site has contacted with each other the case where not generating displacement, so that set B1's
Any movement is done all in site can generate site overlap joint；
2, adjusting method is displaced in order to realize Moire effect, it is contemplated that all sites carry out identical displacement, but set B1In
Site, practical movably distance is the distance between two site closest approaches D1, in the state of the art, still
Do not have and relevant further investigation, few some subjective judgements for being also limited to shallow-layer are carried out to the movable distance of boundary node
In theoretical basis.According to displacement adjusting method, the mobile distance in all sites is D/2, and moving direction is the direction of screen angle
(i.e. along the cable direction of formation), the present invention in find, work as D/2=D1When, the site after moving at this time is just and in front of it
Site be in contact but do not overlap, due to that can be arranged screening parameter in halftone process early period, screen frequency is datum,
Screen frequency has determined the side length D of the D and mesh tune unit in the distance between two neighboring site2, D=D2, two sites are most
The distance between near point D1Equal to the value that the distance between two neighboring site D subtracts two radius r, certain in screen frequency
In the case of, D1Site radius r is then depended on, and site radius depends on dot percentage α, 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, is influenced in photoshop by output resolution ratio, dot shape is not necessarily therefore the circle of standard takes α
Integer is 0.2；It is threshold value with α=0.2；
When site mobile according to traditional bit transposition section method, set B1In site can be taken with the site in front of its moving direction
Connect, site overlap joint can cause very big counter productive to anti-counterfeiting information concealment, the visual perception of lap-joint clearly, especially
It is the site or borderline site of lap-joint, and the profile of anti-counterfeiting information can be made just to be perceived by the human eye before extraction, led
Cause antiforge function failure；Therefore, in the present invention, only when α is less than or equal to 0.2, with reference to existing displacement adjusting method, using X
Horizontal and vertical displacement is respectively indicated with Y, displacement adjusting is carried out to the site of set A,In this range
It is interior, the hiding of anti-counterfeiting information may be implemented and extract, whereinWhen, it extracts recognition performance and reaches most preferably, displacement algorithm
It can be expressed as again：
(2), (the mobile D/2 on screening direction), set as α > 0.2, site mobile according to traditional bit transposition section method
B1In site can be overlapped with the site in front of its moving direction, site overlap joint anti-counterfeiting information concealment can be caused it is very big
Counter productive, clearly, the especially site of lap-joint or borderline site can to prevent the visual perception of lap-joint
The profile of fake information is just perceived by the human eye before extraction, and antiforge function is caused to fail；
To guarantee certain concealment, while guaranteeing set B again1Can contribute to extract identity, when it is mobile away from
It is less than or equal to D from being greater than 01When, the hiding of anti-counterfeiting information may be implemented and extract, it is specific as follows：
0 < S≤D1；
And because：
So site is as follows in horizontal and vertical displacement algorithm in set A：
Show that when site is mobile be maximum distance D by many experiments test1When, it extracts performance and reaches best.
Information concealing method of the invention can improve concealment simultaneously and extract identity, and also reduce work
Amount, specific aim is stronger, meanwhile, operationally, advanced line position transposition section improves dot percentage again, is further improved site percentage
The purpose of ratio is to improve concealment, and after the displacement of site, the site far from movement can generate larger sky with the site of surrounding
Gap forms intensive dot area with the site in front of the direction of motion, if not improving site hundred so close to the site of movement
Divide ratio, so that a part of site is excessively sparse, another part site is excessively intensive, causes visual perception, in addition, of the invention changes
Workload can be reduced into method and reduces operation difficulty, effectively avoid the generation of error, meanwhile, borderline site is to raising
Concealment and identity are made contributions；It is prefabricated improved new site that dot percentage, which improves specific operating method, should
Site has new dot percentage, and erasing needs improved site in photoshop, is then added at corresponding position
New site.
3, it is extracted the stage in anti-counterfeiting information, the present invention point research decodes the deficiency of grating in the prior art, carries out comprehensive section
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 0.1≤α≤0.2 when, T1Width range be 2r≤T1< S, i.e.,Within this range
The decoding grating being prepared, can clearly extract anti-counterfeiting information, not be only T1Anti-fake letter can be just extracted when=2r
Breath, and in the present embodiment, with T1Increase, the contrast grade of extraction also increases simultaneously, it is easier to identify in extraction anti-fake
Information；And becauseThereforeIt is equivalent to：
When showing 0.2 < α≤0.5 by many experiments test, the site within the scope of this is more intensive, if continued
Increase, there is no too big raising to recognition performance is extracted,When, the extraction performance of grating identification reaches best；Therefore
T1Calculation method be：
The present invention, which has, targetedly designs grating, and anti-counterfeiting information can just be obtained based on moir patterns in the prior art by breaking
Technology prejudice, the covering width of design decoding grating, clarity and resolution when raising grating decodes as far as possible, so that
In use, can more aspect progress anti-counterfeiting information verifying.
Claims (10)
1. a kind of hidden method of improved moir patterns grating anti-counterfeiting information, 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 channel 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,
And α is 0.1~0.5；
Select any one channel with the identical region of dot percentage as encrypted tunnel, remaining channel is 3 common
Channel, to 4 channels be respectively set screening parameter carry 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；Remember that the screen frequency is l, screening parameter further includes screen angle, screen angle include 0 °, 18.44 °, 45 ° and
71.57 °, remember that the screen angle of the encrypted tunnel is θ, θ is 0 °, the screen angles of 3 Common passageways be 18.44 °, 45 ° and
71.57 any combination；
(2), site is displaced
Remembering to correspond in encrypted tunnel half-tone picture has the identical region of dot percentage for encryption section；What selection needed to hide
Anti-counterfeiting information establishes site constituency according to the profile of anti-counterfeiting information in encryption section, remembers that the site in the constituency of site is set
The site of set A is displaced by A, and direction of displacement is vertically upward or vertically downward shift length S, and displacement algorithm is：
(3), dot percentage improves
Remember that the collection for being located at the site on the selection border of site in the site of 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 carrying out displacement and adjusting, 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 B2Encrypted tunnel half-tone picture between the corresponding site set G, 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；
(5), anti-counterfeiting information extracts
Analog codec grating is prepared, decoding grating is parallel to each other 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,The T1Calculation method 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 completes the extraction of anti-counterfeiting information.
2. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 1, it is characterised in that：Institute's rheme
Moving algorithm is：
3. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 1, it is characterised in that：The T1
Calculation method be：
4. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 1, it is characterised in that：The original
Original text is the digital document opened using photoshop software, and the screening processing adjusts screen using half in photoshop, often
The method that a channel carries out screening processing is：Channel is chosen, channel is converted into bitmap, when conversion is arranged the output and differentiates
Then rate adjusts screen to the processing of channel screening using half, the screen frequency is 50~200lpi.
5. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 4, it is characterised in that：It is described defeated
Resolution ratio is the integral multiple of screen frequency out.
6. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 4, it is characterised in that：It is described to add
Screen density is 96lpi, output resolution ratio 2400dpi.
7. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 1, it is characterised in that：It is described anti-
Fake information is text and/or figure.
8. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 7, it is characterised in that：It is described anti-
Fake information is text, and the site displacement is completed using photoshop software, and the method for establishing site constituency is：
(1), new image one in photoshop, the length and width of image one and the length and width of original copy are identical, 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 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.
9. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 7, it is characterised in that：It is described anti-
Fake information is figure, and the site displacement is completed using photoshop software, and the method for establishing site constituency is：
(1), new image two in photoshop, the length and width of image two and the length and width of original copy are identical, the resolution ratio of image two 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 encrypted tunnel
It changes the line map and is copied into image two, 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.
10. the hidden method of improved moir patterns grating anti-counterfeiting information according to claim 1, it is characterised in that：It is described
Image synthetic method is：
New image three in photoshop, the length and width of image three and the length and width of original copy are identical, the resolution ratio of image three and described
Output resolution ratio is identical, and background content is white, and color mode is CMKY mode, 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.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
-
2018
- 2018-05-25 CN CN201810545634.3A patent/CN108881661A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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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