JPH02148382A - Paper money discriminating device - Google Patents

Abstract

PURPOSE:To accurately identify the propriety and kind of a paper money by providing photosensors which measure quantities of light at each point on the surface of the paper money after the light is passed through the paper money. CONSTITUTION:Light transmissive type photosensors P1-Pn measure quantities of light at each point on the surface of a paper money after the light is passed through the paper money to be identified. Data of the light quantities measured by the sensors P1-Pn at each point except the whole marginal section of the paper money to be identified are collected to an arithmetic section 1 and the standard deviation value Sk of the frequency distribution of the data above a set value is found. On the other hand, standard deviation values So related to the watermark of each kind of paper money is set at a setting section 3. A identifying section 2 detects the coincidence between the deviation values Sk and So within a prescribed allowable range and, when the values Sk and So coincide with each other, the kind of the paper money is identified. When the paper money does not coincide with any kind of paper money, the paper money is identified as a counterfeit paper money.

Description

[Detailed description of the invention] [Industrial application field]

The present invention particularly relates to a banknote discrimination device that discriminates the authenticity or denomination of banknotes based on the characteristic amount related to the watermark portion of banknotes.

[Conventional technology]

Conventional banknote identification devices detect magnetic patterns on banknotes,
The authenticity or denomination of a banknote is discriminated based on the optical pattern based on transmission and two reflections related to the picture, or the dimensions, either alone or in combination.

[Problem to be solved by the invention]

It is desired to accurately grasp the characteristics of banknotes using new technical clues that are not based on the conventional techniques as described above, and to discriminate banknotes with high accuracy based on this. In other words, this is an appropriate measure against counterfeiting or alteration of banknotes. To this end, we have focused on watermarks that are unique to banknotes, and have considered identifying these watermarks and understanding their characteristics. It is an object of the present invention to provide a banknote validating device that solves the above-mentioned problems of the conventional techniques and accurately determines authenticity or denomination based on features related to the watermark portion of banknotes.

[Means to solve the problem]

In order to solve this problem, the banknote validation device according to the present invention includes: an optical sensor that measures the amount of light transmitted at each location on the surface of the banknote to be validated; Based on the amount of transmitted light determined by the optical sensor as ff1l+, the characteristics of the watermark portion, such as the tendency of the frequency distribution of the amount of transmitted light related to the watermark portion, the area of the watermark region, or the position of the center of gravity of this region, etc. a calculation unit that calculates the value of; and a determination unit that identifies the authenticity or denomination of the banknote to be verified based on the output of the calculation unit and the set value for each denomination among the characteristics.

[For use]

The arithmetic unit calculates the characteristics of the watermark of the banknote to be verified, such as the tendency of the frequency distribution of the amount of light transmitted in the watermark, the area of the watermark area, or the position of the center of gravity of this area. The authenticity or denomination of the banknote to be verified is specified based on the values between the features and the denomination-specific set values between the features.

【Example】

Embodiments of the banknote validating device according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram commonly showing the configuration of this embodiment, in which PL, P2. P3. -, Pn
are translucent optical sensors that measure the amount of light transmitted at each location on the banknote. Calculation units 1 and 11 identify the watermark portion of the banknote and determine the characteristics of the watermark portion, such as the tendency of the frequency distribution of the amount of light transmitted in the watermark portion, or the center of gravity of the watermark region. 3.13 is a setting section, which sets setting values corresponding to each of the above-mentioned features. 2.12 is a determination unit that compares the outputs from the calculation units 1 and 11 with the outputs from the setting units 3 and 13 to identify the authenticity or denomination of the banknote. E is the special @ quantity of the watermark part, K is a setting value, and J is a judgment signal. Note that the calculation section 111 constant section 2. The setting unit 3 constitutes one embodiment, and handles standard deviation indicating a tendency of variation in the frequency distribution of the amount of transmitted light related to the watermark portion as a feature. In addition, the calculation unit 111 and the determination unit 12. Another embodiment is configured with a setting unit 13, and the center of gravity position of the watermark area is treated as a feature. FIG. 2 is a plan view of the transported banknotes and the optical sensor array, and in the figure, optical sensors PI, P2. P3. ..., Pn, the rows of which are perpendicular to the conveyance direction parallel to the short side of the banknote Bi,
And they are arranged so as to have a slightly wider range than the longitudinal dimension of the banknote BiO. Note that the banknotes Bi are i=1, 2, .
3 represents a 1,000 yen bill, a 5,000 yen bill, and a -10,000 yen bill, respectively. In FIG. 2, depending on each transport position of the banknote Bi, the amount of light transmitted at each location on the surface of the banknote Bi is determined by the optical sensor P1. P2.
P3. ..., measured by Pn. Because the watermark part is thin and has no pattern printed on it, the amount of light transmitted is thicker than other parts (and exceeds a certain setting value C.The entire periphery of the banknote Since there is no pattern, it is necessary to pay attention to the fact that the amount of light transmitted is slightly higher than other parts.Therefore, it is possible to identify the watermarked part by the part where the amount of light transmitted is higher than this set value C. Figure 3 is an explanatory diagram schematically showing the watermark part of a banknote, in which Ti is the watermark part of the banknote Bi, Ai is the area of the watermark area, Gi is the center of gravity of the watermark area, and Xi ,
Yi is the position of the center of gravity Gi, and is expressed as a distance measured in the horizontal and vertical directions from the lower left corner when viewed from the front side of the banknote Bi in the normal direction. Note that i-1, 2, and 3 represent a 1,000 yen bill, a 5,000 yen bill, and a 20,000 yen bill, respectively, as described above. FIG. 4 is a frequency distribution diagram (histogram) of the amount of light transmitted in the watermark portion of a banknote, in which the horizontal axis represents the light transmitted IH, and the vertical axis represents the frequency N. In this frequency distribution diagram, all the values of the amount of transmitted light are equal to or higher than the previously set value C, and are distributed with a certain spread around a certain value. in general,
The trends in the frequency distribution are related to its central position and to halakki (fluctuation). The former is expressed by the average value, median value, maximum value, etc., and the latter is expressed by each value such as standard deviation, 2 variance, and range. In the frequency distribution diagram of the amount of transmitted light in FIG. 4, the average value Mi and the standard deviation value Si are shown. Returning to FIG. 1 again, the operation of one embodiment will be described. The calculation unit 1 collects data on the amount of light transmitted at each location of the banknote to be verified, excluding the entire periphery, as measured by each optical sensor. The standard deviation value Sk of the frequency distribution is determined based on the frequency distribution. On the other hand, the setting unit 3 sets the standard deviation values S ol , S o2 . So3 is set. In the determination unit 2, the standard deviation value Sk and each standard deviation value Sol, So2. The degree of matching with So3 is tested within a predetermined tolerance range, and the denomination that is tested as matching is the discrimination result that should be obtained. If the banknote does not match any denomination, it is determined to be a counterfeit banknote. The operation of another embodiment is as follows. The calculation unit 11 collects data on the amount of light transmitted at each location of the banknote to be discriminated, excluding the entire periphery, measured by each optical sensor. The centroid positions IXk and Yk of the watermark area are determined based on the watermark area. On the other hand, the setting unit 13 determines the center of gravity position of the watermark area of each denomination banknote Xol, Yol; Xo2. Y
o2; Xo3. Yo3 is set. In the determination unit 12, the previous center of gravity position Xk. Yk and each center of gravity position Xol, Yol; Xo2.
Yo2; Xo3. The degree of coincidence with Yo3 is tested within a predetermined tolerance range, and if the denomination fails, the denomination tested is the discrimination result to be obtained. If the banknote does not match any denomination, it is determined to be a counterfeit banknote. In the above example, the standard deviation value of the frequency distribution of the amount of transmitted light related to the watermark area and the center of gravity of the watermark area were selected independently as the feature values, but the frequency distribution The average value, 1 variance, and the area of the watermark area can be selected. Further, by testing the degree of coincidence for each denomination by combining a plurality of denominations instead of using each denomination individually, it is possible to naturally improve the identification accuracy. [Effects of the Invention] According to the present invention, compared to conventional techniques, as a result of focusing on the watermark portion that clearly expresses the characteristics of banknotes, the excellent effect is that highly accurate identification results can be obtained by relatively simple means. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram commonly showing the configuration of an embodiment according to the present invention, FIG. 2 is a plan view of conveyed banknotes and an optical sensor array, and FIG. 3 is an explanatory diagram schematically showing a watermark portion of a banknote. FIG. 4 is a frequency distribution diagram of the amount of light transmitted in the watermark portion of banknotes. Code explanation Bj: Banknote (i=1.2.3), PI, P2. P3s..., Pn: Optical sensor, 1.1
1: calculation section, 2.12 = judgment section, 3.13: setting section. 1st invitation 2nd drawing

Claims (1)

[Claims] 1) An optical sensor that measures the amount of light transmitted at each location on the surface of the banknote to be verified; a calculation unit that calculates the value of the feature amount of the watermark portion based on the amount of transmitted light;
A bill validating device comprising: a determining unit that identifies the authenticity or denomination of the banknote to be validated based on the output of the calculation unit and the set value for each denomination of the feature amount. 2) The bill validating device according to claim 1, wherein the feature amount is a tendency of the frequency distribution of the amount of light transmitted in the watermark portion. 3) A bill validating device according to claim 1, wherein the feature amount is an area of a watermark region. 4) The bill validating device according to claim 1, wherein the feature amount is the position of the center of gravity of the watermark area.