JPH103561A - Method for discriminating authenticity of paper sheets - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the probability of producing errors at the discrimination of authenticity and to improve the capacity of authenticity judgement by irradiating a specific part of a paper sheet with two ultraviolet beams having respectively different wavelengths, receiving respective excited beams from the specific part, recognizing the color distribution of three primary colors, and comparing the recognized color distribution with previously registered reference color distribution. SOLUTION: Two light sources are respectively emitted, an image of paper money is received by R, G and B sensors and respective digital values of R, G and B signals are stored in a memory 4 through an amplifier part 1, a multiplexer 2 and an A/D converter 3. The stored digital values of the R, G and B signals are sent to an arithmetic processing part 5, density correction is executed by a density correcting means 5a and the density corrected values are expressed as the density value histograms of respective signals. The histograms are compared with the contents of a reference table memory 5d for storing reference density histograms in each money sort and each wavelength. When the density value histograms of the R, G and B density values entered each wavelength are the same as the reference histograms, the paper money is judged as true money.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging the authenticity of paper sheets printed with fluorescent inks that emit fluorescent light of different excitation wavelengths when irradiated with ultraviolet light of different wavelengths.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for determining the authenticity of paper sheets such as banknotes, checks, stamps, and the like. . However, since the method of detecting the magnetic characteristics often misleads the system by magnetic copying, recently, data such as an optical waveform obtained using an optical sensor and genuine paper sheets registered in advance are used. Truth judgment by comparison with data has also been developed.

As a light sensor, it is common to irradiate a sheet with visible light or infrared light as a light source, and read the reflected light or transmitted light with a CCD sensor or a phototransistor array. In addition, as a countermeasure against counterfeit bills, bills partially printed with ink with fluorescent properties have been issued.Especially in Europe, ultraviolet rays are used to check the authenticity at the counters and shops of financial institutions. ing.

[0004] When an ultraviolet sensor is used for this authenticity check, one ultraviolet sensor having a wavelength of 365 nm is installed as a detection area in a banknote in order to generally detect a portion of a printed pattern containing fluorescent light. ing. However, with the ultraviolet sensor that detects only the wavelength region of 365 nm, since the printing method of banknotes that are currently in circulation is changing over time, it is possible to sufficiently cope with all new and old bills. It is impossible to do so, and a genuine bill may be mistakenly recognized as a counterfeit bill.

In order to determine the authenticity of a bill by collecting bill data with an optical sensor and comparing the data with authenticity data registered in advance, it is necessary to sufficiently cope with all new bills and old bills. 2 different wavelengths
Japanese Patent Application Laid-Open No. Hei 6-236473 discloses a method in which two ultraviolet rays are simultaneously applied to a bill so that a bill rejected in only one wavelength band is determined as a normal bill. Also, in the case of judging a bill printed with ink having a property of absorbing infrared rays, a reading means for reading visible light information and information other than visible light of a bill pattern as an electric signal, and a visible light read by the reading means. And comparing means for comparing the read signal and the read signal other than visible light, when reading a specific mark other than visible light to be detected,
Japanese Patent Laid-Open No. 6-217123 discloses an apparatus for comparing a signal level of read information other than visible light with a signal level of read information of visible light to determine whether or not the information other than visible light belongs to a specific mark. No. 6,086,045.

[0006]

Recently, banknotes printed with inks that fluoresce at different excitation wavelengths when irradiated with ultraviolet light of different wavelengths, such as 5
Zero franc banknotes are appearing. At the time of determining the authenticity of a sheet having such a light emission characteristic, when the conventional method described in each of the above publications is used, for example, when there is an abnormality such as a tear in the determination area of the sheet, it is obtained. There is a problem that an error occurs in the determination because the corresponding part of the data is missing. Further, in the method described in JP-A-6-236473, only the presence or absence of fluorescent printing can be detected. However, for example, when paper sheets have stains, the color is not observed. There is an inconvenience of determining that part as a fluorescent light emitting part.

The present invention has been made in view of the circumstances described above, and an object of the present invention is to utilize the property that the wavelength range of the fluorescent emission color is different when the wavelength of the ultraviolet light applied to the paper sheet is different, and It is an object of the present invention to provide a method of judging the authenticity of paper sheets, which detects not only the presence / absence of fluorescent light but also color information and further enhances the authenticity judging ability of bills.

[0008]

According to the present invention, there is provided a method for judging the authenticity of a paper sheet which emits a different fluorescent color when a specific portion is irradiated with ultraviolet light having a different wavelength. A first ultraviolet irradiation unit and a second ultraviolet irradiation unit that respectively irradiate two ultraviolet rays, and a first light receiving unit that receives each excitation light from the specific unit based on the first and the second ultraviolet irradiation units. Means and a second light receiving means, wherein the first and second light receiving means
This is achieved by a paper sheet authenticity judging method characterized by recognizing the color distribution of primary colors and comparing the paper color with a reference color distribution registered in advance to judge the authenticity of the paper sheet.

Further, in a method of judging the authenticity of a paper sheet which emits a different fluorescence color when a specific portion is irradiated with ultraviolet light having a different wavelength, the ultraviolet irradiation is performed by irradiating the specific portion of the paper sheet with two ultraviolet light having different wavelengths. Means, and a first light receiving means and a second light receiving means for respectively receiving the respective excitation lights from the specific portion based on the ultraviolet light irradiating means.
Receiving the excitation light by the second light receiving means, storing the excitation light in the memory as color image data, and comparing the color image data with data corresponding to the specific portion to determine the authenticity of the paper sheet This is also achieved by a method of determining the authenticity of a paper sheet characterized by performing the above.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Recently, for example, the 5
When a specific portion (fluorescent light emitting portion) is irradiated with two types of ultraviolet rays having different wavelengths, such as 0 francs, a new type of banknote 100 in which the specific portion has a different fluorescence emission color depending on the wavelength of the ultraviolet light has appeared. The graphic 21 in FIG. 7 indicates the wavelength λ1 = 254 nm in the specific portion 20 of the banknote that cannot be visually confirmed.
And an image when irradiating ultraviolet light of λ2 = 365 nm, FIG. 21 emits a lamp when irradiating ultraviolet light of wavelength λ1 = 254 nm, and FIG. 21 turns blue-green when irradiating ultraviolet light of λ2 = 365 nm. Emits light.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a sensor input unit used for authenticity determination of a bill 100, and a bill 10 conveyed along a conveyance path.
0, a light source 13 such as a fluorescent lamp or a xenon lamp.
Then, ultraviolet rays having a predetermined wavelength are irradiated through the filter 14, and the light emitted by the specific portion 20 (see FIG. 7) of the bill 100 is received by the light receiving means 15 such as an RGB sensor. FIG. 2 (A) shows the sensor input section.
Alternatively, they can be arranged as shown in FIG. FIG.
In the example of (A), two sensor input units A and B are bill 1
The light sources 13A and 13B independently irradiate the specific portion 20 of the bill 100 with ultraviolet rays having different wavelengths, and the emitted light is independently received by the light receiving means 15A and 15B. To receive light. In the example of FIG. 2B, the specific portion 20 of the bill 100 is irradiated with ultraviolet rays having different wavelengths simultaneously from the two light sources 13 </ b> A and 13 </ b> B, and the light emitted by the specific portion 20 is subjected to RG.
The light is received by the light receiving means 15C in which the B sensor is integrated. In the present invention, the sensor input unit as described above can be used.

FIG. 3 is a block diagram showing an embodiment of the present invention. The light receiving means is an RGB sensor 15 shown in FIG.
In the case of C, the light received by the RGB sensor 15C is decomposed into three primary colors RGB, amplified by the amplifiers 1a, 1b, and 1c for each channel of the amplifier 1, input to the multiplexer 2, and selected by the multiplexer 2. A / D signals sequentially
The digital value is converted by the converter 3, and the digital value is stored in the memory 4.

Each digital value of RGB stored in the memory 4 is sent to the arithmetic processing unit 5. The arithmetic processing unit 5 includes a density correction unit 5a, a wavelength comparison unit 5b, and a true / false determination unit 5c, and a reference table memory 5d required for the wavelength comparison unit 5b. The RG when irradiating ultraviolet rays of different wavelengths to the reference table memory 5d
Density value histograms of the B component are stored for each denomination. For example, in the specific part of 50 francs in France,
The density value histograms of the RGB components when the excitation wavelength λ1 = 254 nm are as shown in FIGS. 4A, 4B, and 4C. The density value histograms of the RGB components when the excitation wavelength λ2 = 365 nm are as follows. FIGS. 5A, 5B, and 5C show the density value histograms stored as table data. Here, the horizontal axis of the density value histogram represents lightness, and the vertical axis represents the number of pixels of the specific portion having the lightness.

In such a configuration, the operation is shown in FIG.
This will be described with reference to the flowchart of FIG. When a sensor (not shown) detects the end of the bill 100 conveyed by the sheet conveying means for separating and conveying the bills one by one (step S1), the light sources 13A and 13B shown in FIG.
Respectively, the image of the banknote 100 can be received by the RGB sensor 15C, and the image signal is transmitted through the amplifying unit 1, the multiplexer 2, and the A / D converter 3 to R
Each digital value of the GB signal can be stored in the memory 4. Then, as shown in FIG. 7, the length L from the end of the bill 100 to the specific portion 20 is detected. The length L is determined according to the denomination, and when the length L is included in the denomination information registered in advance, the image data is loaded into the memory (step S2). At this time, it is also possible to capture an image of the entire banknote 100, or to capture only the specific unit 20.

From the captured image, the RGB sensor 1
The density of the image is calculated by the R component of 5C.
1 and only the graphic 21 of the fluorescent light emitting portion is extracted as a binary image with the background separated (step S3). Each digital value of the stored RGB signals is sent to the arithmetic processing unit 5, where density correction is performed by density correction means 5a to make it easy to determine, and the density is represented as a density value histogram of each signal. This density value histogram is compared with a reference table memory 5d in which density value histograms of RGB components are stored for each denomination and for each wavelength (step S4).
If the density value histogram in the reference table memory 5d is the same (or within a predetermined allowable range) as the acquired RGB density value histogram for each wavelength, it is determined as a genuine note, and if different, it is rejected (step S).
5).

At this time, if the banknote 100 is forged with a highlighter or the like, the density histogram of each of the RGB components when ultraviolet rays having a wavelength λ1 = 254 nm is used is shown in FIG.
RG in the case of wavelength λ2 = 365 nm as shown in FIG.
The density value histogram of each component B is as shown in FIG. 7B, and since the two have almost the same density value histogram, this counterfeit bill is rejected.

Next, the case where the light receiving section 15 is a CCD sensor will be described with reference to the drawings. FIG. 9 shows a block configuration in the case where the light receiving unit 15 is a CCD sensor. When a CCD sensor is used, a luminance signal, a chrominance signal, and a synchronization signal are composite signals that are superimposed. After converting to. The sensor input unit 6 includes a CCD sensor 6a, a Y (luminance) / C (color difference) separation unit 6b, and a color signal separation unit 6c. An image signal (composite signal) input to the CCD sensor 6a is separated into a luminance signal and a chrominance signal by a Y / C separation unit 6b. Signal, B-
The signal is converted into a Y signal and output.

These three signals are input to an analog multiplexer 7 after their high-frequency components are removed by built-in low-pass filters to prevent aliasing for A / D conversion. The Y signal, RY signal, and B which are serially converted by the multiplexer 7 and sequentially selected.
After the -Y signal is converted to a digital value by the A / D converter 8, the serial / parallel conversion unit 9 converts the Y signal, the RY signal, and the BY signal into parallel. Then, the signal is input to the horizontal / vertical filter circuit 10, where the vertical scanning lines are thinned out and, at the same time, the band is limited so that aliasing noise does not occur. The signal thus thinned out is finally stored in the memory 11.

Each digital signal stored in the memory 11 is sent to the arithmetic processing unit 12. The arithmetic processing unit 12 has RG
B separation means 12a, density correction means 12b, wavelength comparison means 12c, density value histogram pattern matching means 1
2d, a true / false judgment means 12e, and a density value histogram calculation means 12c required for the wavelength comparison means 12c.
1, sum calculation means 12c2, average value calculation means 12c3,
A peak value calculation means 12c4 is also provided. Further, a reference table memory 12f required for the wavelength comparing unit 12c and the density value histogram pattern matching unit 12d is also provided.

Each digital signal sent to the arithmetic processing section 12 is first converted into a component signal by RGB separating means 12a. Here, the RGB separation means 12a
Will be described. For example, when a CCD sensor for a television camera is used as the CCD sensor 6a of the sensor input unit 6, RY of RGB signals and each color difference signal is used.
The relationship between the signal, the GY signal, the BY signal, and the luminance signal Y can be expressed as shown in Equation 1.

[Number 1] _{E Y = 0.3 × E R +} 0.59 × E G + 0.11 × E B E R-Y = 0.7 × E R -0.59 × E G -0.11 ×
_{E B E G-Y = -0.3} × E R + 0.41 × E G -0.11
_{× E B E B-Y =} -0.3 × E R + 0.59 × E G +0.89
× E _B (E is the voltage value of each signal)

[0021] G-Y signals to retrieve from the R-Y signal and B-Y signals, from the number _{1 E G-Y = -0.51 ×} E
_R−Y− 0.19 × EB _−Y , and RGB signals can be obtained.

In such a configuration, the operation is shown in FIG.
This will be described with reference to the flowchart of FIG. When a sensor (not shown) detects the end of the conveyed bill 100 (step S11), the light source 13 is caused to emit light and image data is captured by the CCD sensor 6a (step S1).
2) After performing the extraction processing of the identification unit 20 (step S1)
3) As described above, the respective signals pass through the Y / C separation unit 6b, and the Y signal, the RY signal,
Convert to BY signal. Further, the multiplexer 7, A /
D converter 8, serial / parallel conversion unit 9,
The signal processing as described above is performed in the horizontal / vertical filter circuit 10, and each signal is stored in the memory 11.

Each signal stored in the memory is appropriately sent to the arithmetic processing unit 12, and is separated into RGB signals by the RGB separation unit 12a (step S14). After the density correction by the density correction unit 12b for easy reading, The sum value, the average value, and the peak value of each of the RGB signals of each wavelength are calculated by the density value histogram calculation means 12c1, the sum calculation means 12c2, the average value calculation means 12c3, and the peak value calculation means 12c4, respectively, and / or the density value. A histogram is obtained (step S15). The calculated values and / or density value histograms are compared with the above-described values and / or density value histograms stored in advance in the reference table memory 12f by the wavelength comparison means 12c to determine whether the bill is genuine. It is determined whether it is (Step S16).

FIGS. 11A, 11B, and 11C are flow charts showing an example of the operation of the determination processing in step S16. In FIG. 11A, the density value histogram obtained in the signal processing in step S15 is shown. Only the value in the reference table memory 12f is subjected to pattern matching with the value in the reference table memory 12f (step S161), and it is determined whether the value is within the allowable range or out of the range (step S162). If it is within the allowable range, it is determined to be genuine, and if it is outside the range, it is rejected. In FIG. 8B, the total value, average value, and peak value obtained in step S15 are compared with the total value, average value, and peak value stored in advance for each denomination ( In step S163), if all of the values match the stored denominations, it is determined to be genuine, and if any one does not match, it is rejected.

Further, as shown in FIG. 11C, first, the total value, the average value, and the peak value obtained in step S15 are converted into the total value, the average value, and the maximum value stored in advance for each denomination. A comparison is made with the peak value (step S163),
If all the values match the stored denominations, density value histogram pattern matching is performed next (step S161) as shown in FIG. 11A, and the value is within the allowable range or out of the range. (Step S16)
2). If it is within the allowable range, it is determined to be genuine, and if it is out of the range, it is rejected. As described above, if the total value, the average value, and the peak value are compared first, and then the density value histogram pattern matching is performed, the authenticity determination ability can be further enhanced.

FIG. 12 shows the relationship between the extracted pixels of the specifying unit 20 and the data. The signal processing in step S15 will be described with reference to FIG. The extracted specific part 20 is divided as shown in the figure, and the portion corresponding to the vertical axis j and the horizontal axis i, that is, the shaded portion in FIG.
Each signal is represented by R1ij, G1ij, B1ij and R2ij,
G2ij and B2ij. The subscript 1 is the excitation wavelength λ1
= 254 nm, and the subscript 2 is the excitation wavelength λ2
= 365 nm.

The following equations (2) and (3) show how to calculate the sum S and the average M for each of the RGB signals using the above signals.

(Equation 2)

Equation 3] _{M R1 = S R1 / hg,} M R2 = S R2 / hg M G1 = S G1 / hg, M G2 = S G2 / hg M B1 = S B1 / hg, M B2 = S B2 / hg here And h: number of pixel columns in the horizontal direction g: number of pixel rows in the vertical direction

In the above equation 3, M _R1 , M _G1 , and M _B1 are the average values of R, G, and B when λ 1 = 254 nm, and M _R2 , M _G2 , and M _B2 are λ ₂ = 365 nm.
The average value of each of R, G, and B at the time of is shown.
Also, only the peak value P is 3 × in order to remove the influence of noise.
The peak value is detected using the value obtained by smoothing the image of No. 3 (averaging 9 pixels). And P _R1 and P
_{R2, P G1} and _{P G2,} denoted _{P B1} and _{P B2.}

FIG. 13 is a detailed flowchart showing an operation example of the signal processing in step S15 and the determination processing in step S16. First, the sum S, the average M, and the peak P at two wavelengths are compared. That is,
A difference is obtained for each of the RGB signals, and it is determined whether all of the following Equations 4 are satisfied (step S151).

S _R1 −S _R2 > 0, M _R1 −M _R2 > 0, P _R1 −P _R2 > 0 S _G1 −S _G2 > 0, M _G1 −M _G2 > 0, P _G1 −P _G2 > 0 _{S B1 -S B2> 0, M} B1 -M B2> 0, P B1 -P B2> 0

If at least one of them is not satisfied, it is rejected. Further, instead of using 0 in Equation 4, a specific numerical value indicating an allowable range for each denomination may be used. And
When all of the above expressions 4 are satisfied, a reference signal is determined from the total value S, average value M, and peak value P of each of the RGB signals, and each value is compared with the value of the reference signal. For example, a difference is determined for each of the RGB signals using the reference signal as a G signal, and it is determined whether all of the following Equations 5 are satisfied (step S152).

S _R1 −S _G1 > 0, S _R2 −S _G2 > 0 S _B1 −S _G1 > 0, S _B2 −S _G2 > 0 M _R1 −M _G1 > 0, M _R2 −M _G2 > 0 M _{B1 -M G1> 0, M B2} -M G2> 0 P R1 -P G1> 0, P B2 -P G2> 0

The signal used as the reference is not limited to the G signal, and it is needless to say that any of the R signal and the B signal may be used as the reference. Then, it is determined whether or not all of the expressions are satisfied. If any of the expressions is not satisfied, it is rejected. Further, when all of the above expressions 5 are satisfied, the values of the sum S, the average M, and the peak P at the two wavelengths are compared again for each of the RGB signals (step S153). However, at this time, instead of taking the difference, the ratio is obtained as shown in the following equation (6), and it is determined whether all of the following equations (6) are satisfied (step S153).

S _R1 / S _R2 > 1, S _G1 / S _G2 > 1, S _B1 / S _B2 > 1 M _R1 / M _R2 > 1, M _G1 / M _G2 > 1, M _B1 / M _B2 > 1 P _R1 / P _R2 > 1, P _G1 / P _G2 > 1, P _B1 / P _B2 > 1

Then, when all of the expressions 6 are satisfied, it is determined that the bill is genuine. If any of them are not satisfied, reject them.

Next, FIG. 14 is a detailed flowchart showing an operation example after the RGB signal for each wavelength is normalized according to the number of pixels in step S16 and a density value histogram is obtained. FIGS. 15A and 15B show density value histograms for each wavelength of the signal R, and FIG. 15C shows the difference between the density value histograms of the above (A) and (B). Represents Then, not only the signal R but also the signal G and the signal B are different from each other, and R3, G3, and B3 are obtained as shown in the following Expression 7 (step S15).
5).

R3 = R1-R2, G3 = G1-G2, B3 =
B1-B2

Further, the equation (7) is expressed by R1-B2, B1-G2, R1
The density value histogram may be obtained by taking the difference of −G2. Then, the density value histogram of the difference obtained by the above equation (7) is stored in the reference table memory 12 registered in advance for each denomination.
Pattern matching is performed with the density value histogram in f (step S156), and it is determined whether they are within the allowable range (step S157). If they are within the allowable range, they are determined as genuine, and if they are different, they are rejected. Further, at the time of pattern matching of the density value histogram, R3 at a specific point in the fluorescent light emitting portion of the bill,
The numerical values of G3 and B3 may be obtained and compared using specific numerical values indicating allowable ranges for each denomination. As described above, the above conditional expressions are compared at the same place of the bill, so that the effects such as torn are canceled. Although the above description has been directed to banknotes, the present invention is also applicable to paper sheets in general.

As described above, according to the method of the present invention, it is possible to determine the authenticity of a paper sheet which emits a different fluorescent color when a specific portion is irradiated with ultraviolet light of a different wavelength. In order to enhance the capability, the RGB signal is converted from the specific unit 20 into a luminance signal obtained from the above equation (1) in order to separate the graphic 21 and the background of the fluorescent light-emitting portion from the specific unit 20 at the time of the RGB separation. By determining whether or not the image is the same as the graphic 21 in the reference table memory, the presence or absence of the fluorescent light emitting portion can be accurately and easily detected.

More specifically, as shown in FIG. 16, the fluorescent light emitting portion of FIG. 21 is binarized and extracted so that the fluorescent light emitting portion of the graphic 21 is 1 and the background, which is the other portion, is 0.
It is assumed that Q pixels have been obtained. Also, here, FIG.
The fluorescent light emitting portion of 1 is 1 and the background other than that is 0.
Is defined as Wij. At this time, the equation corresponding to the above equation 2 is as shown in the following equation 8.

(Equation 8)

Here, S _R1 , S _G1 and S _B1 are λ1 =
It is the sum of R, G, and B at 254 nm, and S _R2 , S
_{G2, S B2} represents the sum of the R, G, B in the case of .lambda.2 = 365 nm. Further, the figure 21 is not limited to the shape shown in FIG. 16, and may be a rectangle, an ellipse, or an arbitrary shape.

An equation for calculating the average value M, which corresponds to the above equation 3, is as shown in the following equation 9.

## _EQU9 ## _MR1 = _SR1 / Q, _MR2 = _SR2 / Q _MG1 = _SG1 / Q, _MG2 = _SG2 / _QMB1 = _SB1 / Q, _MB2 = _SB2 / QQ : Number of extracted pixels of fluorescent light emission part

When a figure which is a fluorescent light-emitting portion with a clear contour is obtained as described above, the influence of the color of the surrounding background can be prevented, and a more reliable determination can be made.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, as a bill 100, 50 of a French bill is used.
How the above conditional expressions in the case of franc are represented will be described. RGB signals at a specific point in the fluorescent light emitting portion of the French banknote of 50 francs are R1 = 241, G1 = 201, B1 = 173 when λ1 = 254 nm,
When λ2 = 365 nm, R2 = 187, G2 = 253,
B2 = 187. Here, the difference between the RGB signals for each wavelength is expressed by the following equation (7) as in the following equation (10).

R3 = R1-R2 = 54> 20 G3 = G1-G2 = -52 <-20 B3 = B1-B2 = -14 <-10

The values -20, 2
0 and 10 are the above-described allowable ranges, which differ for each denomination, and are stored in the reference table memory 12f.

Next, the bill 100 is a counterfeit note or the above-mentioned specific portion 2.
When the graphic 21 of the fluorescent light emitting portion of 0 is forged with a highlighter pen, the above signals are R1 ≒ R2, G1 ≒ G2, B1 ≒ B2.
And the above conditional expressions are not satisfied, and R1-G1 <0 is rejected.

[0043]

As described above, in the method according to the present invention, the probability of an error in the authenticity determination by the fluorescent sensor is reduced, and even if the paper sheet has a missing part such as a tear, the mutual wavelength is not increased. Since there is no influence on the pattern matching, the ability to determine the authenticity is further enhanced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a sensor input unit for paper sheets.

FIG. 2 is a diagram illustrating another configuration example of a sensor input unit for paper sheets.

FIG. 3 is a functional block diagram showing one embodiment of the present invention.

FIG. 4 is a diagram showing an example of a density value histogram of each of RGB signals in a fluorescence emission portion when an excitation wavelength is 254 nm.

FIG. 5 is a diagram illustrating an example of a density value histogram of each of RGB signals in a fluorescence emission portion when an excitation wavelength is 365 nm.

FIG. 6 is a flowchart showing an operation example of a bill authenticity determination according to the present invention.

FIG. 7 is a diagram showing a specific portion including a fluorescent light emitting portion of a bill.

FIG. 8 is a diagram illustrating an example of a density value histogram of each of RGB signals in a fluorescent light emitting portion when forged with a highlighter pen.

FIG. 9 is a functional block diagram showing another embodiment of the present invention.

FIG. 10 is a flowchart showing an example of the operation of determining the authenticity of a bill according to the present invention.

11 is a flowchart illustrating a detailed operation example of signal processing in FIG. 9;

FIG. 12 is a diagram illustrating a relationship between pixels and data in a specific unit.

FIG. 13 is a flowchart illustrating a detailed operation example of a determination process in FIG. 10;

FIG. 14 is a flowchart illustrating a detailed operation example of signal processing in FIG. 10;

FIG. 15 is a diagram showing a density histogram of R at two wavelengths and a difference between the histograms.

FIG. 16 is a diagram illustrating a specifying unit that binarizes a background that is a fluorescent light emitting portion and other portions.

[Explanation of symbols]

 Reference Signs List 1 amplifying unit 2, 7 multiplexer 3, 8 A / D converter 4, 11 memory 5, 12 arithmetic processing unit 6 sensor input unit 9 serial / parallel conversion unit 10 horizontal / vertical filter circuit 13 light source 15 light receiving unit 20 specifying unit 100 banknote

Claims (4)

[Claims] 1. A method for judging the authenticity of a sheet that emits a different fluorescent color when a specific portion is irradiated with ultraviolet rays having different wavelengths, wherein the specific portion of the sheet is irradiated with two ultraviolet rays having different wavelengths. A first ultraviolet light irradiating means and a second ultraviolet light irradiating means; a first light receiving means and a second light receiving means for respectively receiving the respective excitation lights from the specific portion based on the first and second ultraviolet irradiating means; And the first
And a second light receiving means for recognizing the color distributions of the three primary colors and determining the authenticity of the paper sheet by comparing it with a reference color distribution registered in advance. False judgment method. 2. A method for judging the authenticity of a paper sheet that emits a different fluorescent color when a specific portion is irradiated with ultraviolet light having a different wavelength, wherein the specific portion of the paper sheet is irradiated with two ultraviolet rays having different wavelengths. Means for receiving the respective excitation lights from the specific portion based on the ultraviolet irradiation means.
The light receiving means and the second light receiving means are provided, and the excitation light is received by the first and second light receiving means and stored as color image data in a memory, respectively, in the specific part of the color image data. A method of judging the authenticity of a paper sheet, wherein the authenticity of the paper sheet is determined by comparing the data with corresponding data. 3. The method according to claim 1, wherein the excitation light excited from the specific portion of the paper sheet is received by one light receiving unit. 4. The method according to claim 2, wherein the shape comparison of the fluorescent light emitting portion is added to the data comparison.