CN1971636A - Method and device for true-false identifying of paper ticket based on infrared identifying watermark - Google Patents

Abstract

The invention relates to a method and device for discriminating the genuine-fake of paper receipt based on infrared discrimination watermark. The receipt to be detected is through the infrared field via transmission means, the optical receiver covered with watermark pattern detects the transmitted light in the watermark area of receipt in motion procedure, complete the photoelectric signal conversion; output to the sampling module and the digital signal characterized the watermark is obtained by analogue/digital conversion; the analog of watermark which is obtained from the mathematical model complex characterization is as the criterion to discriminate genuine or fake to judge the genuine-fake of the watermark, the central processing unit executes the recognition program of discriminate genuine or fake of watermark, and output the discrimination result. The central processing unit is connected with the controller and memory, the controller is connected with the transmitting means. The invention discriminates genuine or fake by computer module discrimination technique, and the false proof means can be processed by more advanced and accurate device, and make the speed of discrimination technique more fast and the result more accurate.

Description

Differentiate the method and the device thereof of paper-ticket, certificate based on infrared identifying watermark

One technical field

The present invention relates to a kind of with the distinguishing method between true and false of watermark as the paper-bill of anti-counterfeiting characteristic card and securities, particularly a kind of method and device thereof based on infrared identifying watermark discriminating paper-ticket, certificate.

Two background technologies

Watermark is a kind of pattern that is embedded in paper inside.Be to pass through special process in the paper-making process, artificially control local paper fibre density, a kind of special optical characteristic of formation.Paper technology therefore also just can't counterfeit and " clone " watermark in case end just can not be pressed specific pattern change fibre density again.This characteristic that can not be counterfeit makes it to become a kind of false proof means that paper ticket extensively adopts.For example the banknote in the circulation of countries in the world almost all uses watermark as main anti-counterfeiting characteristic without exception.

Because the automatic true and false of gathering the watermark feature and being used to differentiate paper ticket, technology is very difficult on realizing, thisly just occur, and be widely used in the technology of ticket anti-pseudo made of paper, also rest on naked eyes so far and intuitively observe on its level that whether exists as far back as 13rd century.Particularly under the situation of mass disposal ticket, limitation because of vision, often can only see the shape of watermark, and can not find to cause the very high anti-counterfeiting technology of this anti-forgery intensity to fail really to bring into play its due usefulness because fibre density changes the profound optical characteristics that produces.

Three summary of the invention

The objective of the invention is to make full use of the paper fibre density changes and the optical characteristics of generation, therefrom gather the anti-counterfeiting information that watermark is implied, processing by modern information technologies is handled, and forms the criterion of differentiating truth/false of watermark, and differentiates the method and the device thereof of paper-ticket, certificate according to watermark.

The technical solution that realizes the object of the invention is: a kind of method based on infrared identifying watermark discriminating paper-ticket, certificate the steps include:

1, tested ticket passes infrared light field motion, and its watermark recovery is by in the process of infrared light scanning, and its transmittance is formed the strong and weak light signal that does not wait by the change modulates of local fibre density;

2, a plurality ofly form a line with ticket direction of motion is vertical, the optical receiver that covers watermark recovery detects the transmitted light of ticket watermark areas in the ticket motion process, finish electro-optical signal conversion;

3, electric signal is carried out with the sampling of ticket synchronized movement and through mould/number conversion, obtain a digital signal that characterizes the watermark feature;

4, " mould " of the true watermark feature that will obtain by the mathematical model comprehensive characterization judges the true and false of detected watermark on this basis as the criterion of discerning the false from the genuine;

5, the result is differentiated in output.

A kind of device of differentiating paper-ticket, certificate based on infrared identifying watermark, it is characterized in that: it comprises the gearing that produces the ticket motion, analog/digital converter, central processing unit, storer and controller, infrared light supply, the optical system that the transmitted light receiver constitutes is arranged on the gearing, the optical receiver receiving optical signals is also finished the electric signal that electro-optical signal conversion output reflects watermark recovery, be connected on the sampling module, sampling module is carried out the pattern recognition program of identification watermark through A/D converter and central processing unit, central processing unit connects controller and storer, and controller is connected with gearing.

Principle of the present invention is: 1, watermark is embedded in paper inside, be divided into individual layer and multilayer (multilevelwatermark) two classes, the former claims the plain boiled water seal again, can see the pattern of a monochrome under the printing opacity condition, latter's printing opacity is observed can see that stereoscopic sensation is strong, lifelike picture; 2, watermark is the artificial optical effect of controlling the fibre density of paper and forming in paper-making process, is the basis of differentiating truth/false of watermark.Especially under the micron infrared transmission, transmittance will be modulated by fibre density, form the grey scale signal of different brackets, and false " watermark " though with ways such as impressing, whitewash counterfeit the shape of true watermark, but can't change fibre density, the spe-cial optical effects of true watermark is resolutely can not be getable; 3, with watermark to the modulating action of above-mentioned infrared transmission as the basis of extracting anti-counterfeiting characteristic, just can completely distinguish true and false watermark, differentiate that with this ticket is believable.

Suppose that infrared light supply forms a line with the direction of motion of paper ticket is vertical with n optical receiver, move when paper ticket cuts light, and the signal of optical receiver is sampled that just can obtain the matrix of the capable n row of m, expression is done by given pace:

A＝(a _ij) _mn

Wherein: a _IjBe the element that the capable j of i lists, i=1,2 ..., n---optical receiver number, j=1,2 ..., m---sampling number

Faking the paper ticket of false proof means with a kind of with watermark, all have identical watermark recovery, use the A value that obtains with a kind of method, should be identical in theory.But because in esse tolerance in the paper-making process, the skew of paper ticket movement locus, or the influence that changes because of environmental baseline (for example temperature, humidity change), the watermark feature of paper ticket of the same race has certain discreteness.Therefore the A value of the paper ticket in the circulation should be the assembly average that obtains by the substantive test sample, or the mathematical expectation of discrete variable, and note is done:

$\begin{array}{c}\mathrm{M\ξ}=\mathrm{\Σ}{A}_{\mathrm{\η}}{P}_{\mathrm{\η}}\\ \mathrm{\η}\end{array}$

Wherein η is for participating in the samples tested number, and the big more M ξ of η approaches true value more, and M ξ just is defined as " mould " of true watermark.When tested ticket cutting light moves, also can in kind collect a matrix that characterizes this ticket watermark feature, note is done: A '=(a ' _Ij) _MnFind the solution the variance of A ' and mould, that is: D ξ=M (A '-M ξ) ², just can judge that the watermark of tested ticket departs from the degree of true watermark, can obtain following several situation:

D ξ＜δ---true watermark;

D ξ＞δ---false watermark;

D ξ ≈ δ---suspect.

δ is defined as " threshold " of discerning the false from the genuine, and is determined by the statistical study and the experience of great amount of samples.

The present invention compared with prior art, its remarkable advantage is: adopt the infrared light to the most responsive specific wavelength of paper fibre density modulating action, the implicit anti-counterfeiting information of watermark is fully disclosed, these information are that naked eyes can't be seen; The particularly application of special wavelength infrared light (wavelength is two " windows " of 0.40-0.61 micron and 0.19-0.29 micron) has avoided the pattern of visible light ink printing and nominal value to pollute influence to identification result; The watermark characteristic model that is proposed, carry out the method for real and fake discrimination and finish the device of these work by computer pattern recognition, solved the bottleneck of automatic collection and discriminating truth/false of watermark, make this false proof means of watermark used more first so that accurately equipment handle, make the real and fake discrimination speed of paper ticket faster, the result is more accurate.

Four description of drawings

Fig. 1 is a truth/false of watermark identification device synoptic diagram of the present invention.

Fig. 2 is the calculating " mould " of the devices and methods therefor of differentiating paper-ticket, certificate based on infrared identifying watermark of the present invention and the process flow diagram of " threshold ".

Fig. 3 is a ticket, certificate identification flow of the present invention.

Five embodiments

Below in conjunction with accompanying drawing the present invention is further described.

Differentiate that to detect watermark authenticity of banknotes is an example below, in conjunction with the accompanying drawings the present invention is further described.

In conjunction with Fig. 1, gearing is the mechanical platform that drives the ticket motion; The optical system that infrared light supply and infrared transmission optical receiver constitute is installed on the gearing, makes light pass the ticket of motion, finishes the scanning to watermark recovery; Optical receiver is connected on sampling module and the analog to digital converter, finishes signal form from light to electricity, from the conversion of analog to digital; Enter central processing unit through pretreated signal, carry out watermark identification and ticket, certificate and differentiate needed processing, result is controlled gear train on the one hand, shows on the other hand; Storer is preserved true watermark " mould " and is differentiated the criterion of ticket, certificate.Digital signal input central processing unit (CPU) extracts the feature of describing watermark by mathematical model, and compares with the feature of true watermark, judges the authenticity of watermark; Memory module is remembered the feature of true watermark, the information such as criterion of the true and false watermark of discriminating; Output module shows identification result; Control module is determined next step action of device according to court verdict, continues to handle next under the true ticket situation and opens; Shut down under the false tickets card situation.Connect display device on the central processing unit, be used for showing the differentiation result.

In conjunction with Fig. 2, " mould " is the standard of describing true watermark, and modeling process enters light field from ticket, and transmittance is modulated by the paper fibre density in the process of cutting infrared light motion, the infrared light receiver detects the variation that projection light is forced the way across, and becomes digitized electric signal through sampling and mould/number conversion; Obtain characterizing the data a of watermark feature _IjFind the solution the matrix A=(a of the capable m row of n _Ij) _MnOn the basis that great amount of samples is tested, ask the mathematical expectation of discrete variable, promptly

$\begin{array}{c}\mathrm{M\ξ}=\mathrm{\Σ}{A}_{\mathrm{\η}}{P}_{\mathrm{\η}}\\ \mathrm{\η}\end{array}$

M ξ is exactly true watermark " mould ", through determining to judge " threshold " of difference truth/false of watermark on to the analysis of false watermark and basis that algorithm is giveed training, remembers standby in storer.

In conjunction with Fig. 3, discerning the false from the genuine enters infrared light field from tested ticket, cuts in the ultrared motion process at tested ticket, gathers the data a that describes the watermark feature _Ij'; The eigenwert A ' of calculating quilt discriminating ticket watermark=(a ' _Ij) _MnGet " mould " M ξ of true watermark, and ask the variance of A ' and M ξ, promptly

Dξ＝M(A′-Mξ) ²

Get " threshold " δ,, differentiate the true and false of ticket according to pre-determined criterion; Show court verdict and control gear train.

Gear train is a typical paper money counter, gear train is going into paper money, sending paper money and cash-out machine tool platform of it, infrared light supply and receiver thereof are installed in the infrared light field that is constituted on the tracks of banknote as pick-up unit, guarantee that light can scan the watermarking images of banknote; In the motion of banknote cutting light, transmitted infrared light is by paper fibre density change modulates, and optical receiver is converted to electric signal with the light signal of receiving; Sampling module carries out sampling with its synchronized movement with frequency f to banknote, and is converted to digital signal a ' by A/D converter _Ij, input CPU, finish following Processing tasks:

1, ask the eigenwert A ' of banknote watermark=(a ' _Ij) _Mn

2, the variance of computation of characteristic values and " mould ", i.e. D ξ=M (A '-M ξ) ²

3, judge the true and false of banknote according to setting the ground criterion in advance, following several situation arranged:

D ξ＜δ---genuine notes ticket;

D ξ＞δ---conterfeit note;

D ξ ≈ δ---must banknote under a cloud.

4, when court verdict is " genuine notes ", device continues to handle next and opens banknote; When court verdict was " counterfeit money " or " suspection ", controlling unit commander gear train was shut down, and shows corresponding mark.

Claims (4)

1, a kind of method based on infrared identifying watermark discriminating paper-ticket, certificate is characterized in that step is:

1.1, tested ticket passes the motion of infrared light field, its watermark recovery is by in the process of infrared light scanning, its transmittance is formed the strong and weak light signal that does not wait by the change modulates of local fibre density;

1.2, a plurality ofly form a line with ticket direction of motion is vertical, the optical receiver that covers watermark recovery detects the transmitted light of ticket watermark areas in the ticket motion process, finish electro-optical signal conversion;

1.3, electric signal is carried out with the sampling of ticket synchronized movement and through mould/number conversion, obtain a digital signal that characterizes the watermark feature;

1.4, " mould " of the true watermark feature that will obtain by the mathematical model comprehensive characterization as the criterion of discerning the false from the genuine, and judges the true and false of detected watermark on this basis;

1.5 the result is differentiated in output.

2, the method for differentiating paper-ticket, certificate based on infrared identifying watermark according to claim 1, it is characterized in that: by " mould " and the ground criterion of discerning the false from the genuine of the true watermark feature of mathematical model comprehensive characterization, judge the true and false of watermark, the result is differentiated in output: D ξ＜δ is true watermark; D ξ＞δ is false watermark; D ξ ≈ δ is for suspecting.

3, a kind of device of differentiating paper-ticket, certificate based on infrared identifying watermark, it is characterized in that: it comprises the gearing that produces the ticket motion, analog/digital converter, central processing unit, storer and controller, infrared light supply, the optical system that the transmitted light receiver constitutes is arranged on the gearing, the optical receiver receiving optical signals is also finished the electric signal that electro-optical signal conversion output reflects watermark recovery, be connected on the sampling module, sampling module is carried out the pattern recognition program of identification watermark through A/D converter and central processing unit, central processing unit connects controller and storer, and controller is connected with gearing.

4, the described device based on infrared identifying watermark discriminating paper-ticket, certificate of claim 3 is characterized in that: connect display device on the central processing unit.

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