JPH01233593A - Mobile origin estimation system and sheet paper discrimination system using the same - Google Patents

Abstract

PURPOSE:To enable transform data to be compared with true security data at a reference position and to reduce memory capacity to store the true security data by providing a measuring data storage means, a transform data storage means, a comparison means, and a discrimination means. CONSTITUTION:The gradation of the density of each micro area of a security measured by a measuring part 200 is stored in the measuring data storage area 221 of a storage part 220. A CPU 210 reads out measuring data from the area 221, and decides a mobile origin, and performs coordinate transform so that each apex of a security of the measuring data can be located at the reference position setting the mobile origin as reference. Next, the transform data is stored in a measuring data storage area 222, and a discrimination part 230 compares the true security data read out of a true security data storage area 231 with the transform data read out of the area 222 by a comparison part 232, and discriminates the truth/forgery of the security. Thus, by performing coordinate transform by estimating the mobile origin out of the measuring data, it is possible to always compare with the true security data at the reference position, therefore, the memory capacity for the storage of the true security data can be reduced.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial application field Means for solving the problem to be solved by the invention (i) First invention (1j) Second invention action (i) First invention (11) Second invention embodiment ■, Correspondence between the embodiment and FIG. Overall system configuration (ii) Measurement unit configuration (iii) Storage unit configuration (1v) Determination unit configuration ■, Operation of the example (i) Operation of estimating the movement origin (ii) Overall operation ■, Example Summary ■6 Effects of the invention in terms of variations of the invention [(already required)] Regarding the paper sheet identification system, the purpose of reducing the storage area for genuine bill data is to determine the equation of the first straight line including the first side. Then, determine the equation of the second line that is perpendicular to the first line and includes the second side, and
The movement origin is estimated by estimating the intersection of the straight line and the second straight line.

[Industrial application field]

The present invention relates to a paper sheet R discrimination system, and particularly to a method for estimating a movement origin and a paper sheet discrimination system using the method.

[Conventional technology]

In a system for identifying paper sheets such as banknotes and securities, the entire paper sheet to be inspected (for example, securities) is divided into minute areas, and each minute area is detected by optical sensors, thickness sensors, etc. , color, external shape, etc., converts the measured values into gradation signals, etc., and stores them. The securities are identified based on the results of comparing this measured value with genuine bill data that has been previously measured and stored.

FIG. 5 is a block diagram of a conventional securities identification system.

Hereinafter, the securities subject to identification will be simply referred to as securities.

The conveyance unit 503 of the measurement unit 500 carries the image sensor 501
The security is conveyed to the sensing range of the image sensor 501 so that the gradation of the entire security can be measured.

The image sensor 501 senses the gray scale of each minute area on the surface of the security to which each element corresponds, and converts it into an electrical signal. The electrical signal is analog-digital (A/
D) The converter 502 converts it into a digital value representing the gradation, and stores it in the measurement data storage area 521 of the storage unit 520.

Here, the direction in which the two-dimensional elements of the image sensor 501 are arranged is the X direction, and the coordinates of each minute area of the security are expressed as the X direction, respectively, and the measurement data is divided into array elements corresponding to the coordinates of the minute area. shall be stored.

The transport unit 503 transports the securities so that the long sides are generally in the X direction, but due to misalignment that occurs during transport, the long sides of the securities are tilted with respect to the Y axis when the image sensor 501 It is also conceivable that measurements may be performed using The measurement data measured in such a tilted state will be referred to as skew data hereinafter.

The genuine bill data storage area 531 stores the results of measuring a genuine bill using the same image sensor 501 (genuine bill data) in order to compare the measured data to identify the securities. Since the inclinations of the skew data vary, in order to compare this, genuine bill data at all inclination angles are required.

The central processing unit (CPU) 510 determines the inclination angle θ of the security from the measurement data, searches the genuine note data storage area 531 for genuine note data measured at the inclination angle θ, and uses this as genuine note data for comparison. The discriminating unit 530 is instructed to use it as a.

The discrimination unit 530 compares the measurement data of the security stored in the measurement data storage area 521 with the designated genuine note data, identifies the security based on the result, and displays the input/output unit such as a display or printer. 540 to report the results of the discrimination.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional securities identification system, in order to directly compare the oblique data with the genuine note data, it is necessary to store the genuine note data measured at all tilt angles in the genuine note data storage area 531. . Therefore, there was a problem in that a huge amount of capacity was required to store genuine bill data.

The present invention was created in view of these points, and an object of the present invention is to provide a paper sheet discrimination system that reduces the amount of genuine bill data.

[Means to solve the problem]

(i) First invention FIG. 1(A) is a block diagram of the principle of the moving origin estimation method of the present invention.

Determine the equation of a first straight line that includes the first side.

An equation of a second straight line that is perpendicular to the first straight line and includes the second side is determined.

Estimate the intersection between the first straight line and the second straight line.

Therefore, the system is configured to estimate the movement origin as a whole.

(ii) Second invention FIG. 1(B) is a block diagram of the principle of the paper sheet discrimination system of the present invention.

In the figure, a measuring means 104 measures a desired physical quantity in each minute area of the paper sheet.

The storage means 105 stores the measured values of physical quantities of paper sheets measured by the measuring means 104.

The central processing unit 106 estimates the movement origin from the measured values stored in the storage means 105, rearranges the measurement values stored in the storage means 105 with the movement origin as a reference, and performs coordinate transformation.

The discriminating unit 107 includes a genuine bill data recording means 171. It has a comparison means 172 that compares the genuine note data recorded in the genuine note data recording means 171 and the transformation data obtained by coordinate transformation by the central processing unit 106, and discriminates paper sheets.

Therefore, the overall configuration is such that a movement origin is estimated, a measured value is coordinate-transformed to a reference position using the movement origin as a reference, and paper sheets are discriminated by comparing with genuine bill data at the reference position.

[For production]

(i) First invention Hereinafter, reference will be made to FIG. 1(A).

A point that is a candidate for the movement origin is detected, and the equation of the first straight line is determined so as to include the first side that includes the candidate point. The slope of the second straight line is determined to be orthogonal to the first straight line, and the equation of the second straight line is determined so that the number of strokes is on the first side. The intersection between the first straight line and the second straight line is found, and the intersection is set as the origin of movement.

” 1 unit λ skin Hereinafter, reference will be made to FIG. 1(B).

The measurement values in each minute region of the paper sheet measured by the measuring means 104 are stored in the storage means 105.

The central processing unit 106 estimates a movement origin using a movement origin estimation method from the measurement data stored in the storage means 105, and uses the movement origin as a basis to generate conversion data equivalent to when the paper sheet is measured at a reference position. Perform coordinate transformation so that

The discrimination unit 107 compares the genuine note data recorded in the genuine note data recording means 171 with the converted data after the coordinate transformation by the comparing means 172, and discriminates the paper sheet based on the result.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows the configuration of a securities identification system according to an embodiment of the present invention.

1. Correspondence between the 'J embodiment and FIG. 1 Here, the correspondence between the embodiment of the present invention and FIG. 1 will be shown.

The measuring means 104 corresponds to the measuring section 200.

The storage means 105 corresponds to the storage section 220.

The central processing unit 106 is a central processing unit (CPU) 210
corresponds to

The determining unit 107 corresponds to the determining unit 230.

Genuine bill data recording means 171 stores genuine bill data storage area 23
Corresponds to 1.

The comparison means 172 corresponds to the comparison section 232.

Examples of the present invention will be described below assuming that the correspondence relationship as described above exists.

FIG. 6 is an explanatory diagram of the principle of coordinate transformation.

In Figure (a), the rectangle representing the security is tilted by θ with respect to the XY coordinate axes, and is in an oblique state.

At this time, the coordinate axes and origin can be re-determined to conveniently represent the coordinates of each vertex of the rectangle, and the coordinates of each point of the rectangle can be transformed.

For example, by performing coordinate transformation such that vertex A is the origin and sides AB and AC are the coordinate axes, (
The positional relationship in which the measurement data is tilted by an angle θ with respect to the XY coordinate axes as shown in a) is changed to
It is possible to convert to a reference position that is not tilted with respect to the Y coordinate axis.

When measuring a security by dividing it into minute areas, the positional relationship of the elements of the array that stores the measured values in each minute area of the security,
The measurement value is configured to be stored in the storage area so that the positional relationship of each minute area corresponds. In this case, by rearranging the elements of the array, the coordinate transformation described above can be performed, and measurement data (transformed data) equivalent to that when the security is measured at the reference position can be obtained. As a rearrangement method for performing such coordinate transformation, Bresenham's method is known.

In order to perform the coordinate transformation as described above, it is necessary to determine an origin that serves as a reference for representing the positional relationship of each measurement point in the measurement data. The origin of this coordinate transformation is called a movement origin. As the origin of movement, a point that facilitates expression of the positional relationship of each measurement point is appropriate, so for rectangular paper sheets such as securities, the vertices of the four corners are appropriate. For example, the coordinate of the vertex is X.

Detection is also simple if one of the values of the Y coordinate takes the maximum value or the minimum value and the point with the smallest Y coordinate is set as the candidate point of the movement origin.

However, the security is not always measured in perfect condition; for example, because one end is bent or torn, the vertex that should serve as the movement origin (for example, vertex A) may not be found. be.

Even in such a case, the origin of movement can be determined by estimating the coordinates of the vertex by utilizing the fact that the sides that sandwich the vertex are orthogonal.

l-14u壓What1戊In Figure 2, the securities identification system includes a measurement unit 200 that measures the density gradation of each minute area of the security, a storage unit 220 that stores measurement data, etc., and a storage unit 220 that processes the measurement data. a central processing unit (CPU) 210 that converts the information into converted data, and a determination unit 230 that determines whether the security is genuine or not.
It is formed by an input/output device 240 that outputs the inspection results of securities by the discrimination section 230.

Hereinafter, the securities subject to identification will be simply referred to as securities.

(ii) Structure of Measuring Unit The measuring unit 200 includes a two-dimensional image sensor 201. Analog-digital (A/D) that converts the output of the image sensor 201 into digital data
Converter 202. It is comprised of a conveyance unit 203 that conveys the securities within the sensing range of the image sensor 201.

Here, the directions in which the elements of the two-dimensional image sensor 201 are arranged are defined as the X direction and the Y direction, respectively.

The coordinates of a minute area with a security within the sensing range of the image sensor 201 correspond to the order in which the elements of the image sensor 201 that sense the density of the minute area are arranged in the X and Y directions, and the positional relationship between the minute areas is Saved.

(iii) The storage unit 220 has a measurement data storage area 221. It is formed by a transformed data storage area 222 that stores transformed data that is the result of coordinate transformation of measurement data.

The measurement data is stored such that the positional relationship of the storage location of the output of each element of the image sensor 201 corresponds to the positional relationship of the elements of the image sensor 201. Therefore, the positional relationship between minute areas is also preserved in the positional relationship of storage locations within the measurement data storage area 221.

(iv) Configuration of Discriminating Unit The discriminating unit 230 stores a genuine bill data storage area 231 that stores the results of measurement by the image sensor 201 (hereinafter referred to as genuine bill data) of genuine bills at a reference position, and converts It is formed to include a comparison section 232 that compares the data and genuine bill data.

Here, the genuine note data is assumed to be measured at a reference position where the long side of the genuine note is parallel to the Y direction, for example.

FIG. 3 is a flowchart showing the operation of estimating the movement origin in the embodiment shown in FIG.

FIG. 4 is an explanatory diagram of measurement data when there is a tear in the security.

Hereinafter, reference will be made to FIGS. 2 to 4.

In FIG. 4, each eye on the base corresponds to one element (pixel) of the image sensor 201, and each eye on the base corresponds to the entire sensing range of the image sensor 201. Further, the directions of thick arrows in the figure are assumed to be the X and Y directions.

The CPU 210 extracts the outline data of the security from the measurement data stored in the measurement data storage area 221. For example, a series of diagonally shaded areas in FIG. 4 corresponds to the outline of a security (step 301).

The CPU 210 detects candidate points for the movement origin from the contour data extracted in step 301. For example, a point Q having the minimum value of the Y coordinate is set as a candidate point for the movement origin. (Step 302).

The CPU 210 examines the change in the Y coordinate increment (ΔY) relative to the X coordinate increment (ΔX) of the contour data coordinates in the vicinity of the point Q detected in step 302, and determines whether the sides sandwiching the candidate point are Check to see if they are orthogonal. For example, in FIG. 4, in area C near point R, ΔX
The ratio of c and ΔYC is 1 knee 5, and in area A, ΔXA and Δ
The YA ratio is 5:1.

Since ΔXA/ΔYA×ΔXc/ΔYc=1,
It can be seen that the sides that sandwich the point R are orthogonal. On the other hand, if ΔXA/ΔYA×ΔXC/ΔY c <> 1, it can be seen that they are not orthogonal (step 303).
.

If the sides that sandwich point Q are orthogonal, point Q is the vertex of one of the four corners of the security, so point Q is set as the movement origin (step 304).

If the sides sandwiching the point Q are not orthogonal, the CPU 210 calculates the equation of the straight line 2 that includes the point Q.

For example, the slope of the side that includes point Q is ΔX:ΔY=5:1, so it is a straight line! is expressed as Y=115X+a (a is a constant) (step 305).

The slope of the straight line m perpendicular to the straight line 2 obtained in step 305 is calculated. For example, the slope of straight line i is ΔX:Δ
Since Y=5:1, the slope of the straight line m is ΔX:Δ
It is expressed as Y=1 knee 5 (step 306).

The slope of the straight line m found in step 306 (ΔX
:ΔY=l knee 5) The contour region (region D) that most closely matches is detected, and the equation of the straight line m is determined so as to include that region. For example, Y=-5X10b (b is a constant) (step 307).

The coordinates of the intersection P of the straight line l and the straight line m are determined, and the intersection P is set as the movement origin (step 308).

(ii) The density gradation of each minute area of the security measured by the overall trajectory measurement unit 200 is stored in the measurement data storage area 221 of the storage unit 220.

The CPU 210 reads the measurement data from the measurement data storage area and determines the movement origin as described above.

The CPU 210 performs coordinate transformation based on the movement origin so that each vertex of the security in the measurement data becomes a reference position, and stores the resulting transformation data in the transformation data storage area 2.
22.

The determining unit 230 compares the genuine note data read from the genuine note data storage area 231 and the converted data read from the converted data storage area 222 using the comparing unit 232, and determines whether the security is a genuine note based on the result. The input/output device 240 reports the result of the discrimination.

uLf soup point [Δ As mentioned above, the candidate point of the movement origin is detected from the contour data, and by examining how the regions (sides) of the contour that sandwich the candidate point intersect, the candidate point is determined from the security. If it is one of the four corners, that vertex is set as the movement origin. A straight line that includes a candidate point even if the candidate point is not in one of the four corners! Find the area of the contour that matches the straight line m perpendicular to straight line 2, and find the straight line! , the origin of movement can be estimated by finding the intersection of straight lines m.

As a result, even if the security is torn or has bent edges, the measurement data can be rearranged based on the estimated movement origin and coordinate transformation can be performed so that the positional relationship of the four corners of the security corresponds to the reference position. Therefore, it is possible to compare the measured data of the genuine note at the reference position.

■1 Modification of the invention In the above-described embodiment of the invention, a case was considered in which the vertices of the four corners of the security were estimated and used as the origin of movement. It can be applied as long as it estimates points convenient for representation. Furthermore, it is possible to process values measured by various sensors, not just a two-dimensional image sensor.

In addition, in r [, Correspondence between Examples and FIG. 1],
Although the correspondence between the present invention and the embodiments has been described above, those skilled in the art will be able to easily infer that the present invention is not limited to this and that there are various modifications.

(Effects of the Invention) As described above, according to the present invention, the movement origin is estimated from the measurement data and the coordinate transformation is performed to rearrange the measurement data, and the paper sheets are measured at the reference position. Equivalent data can be obtained.

This makes it possible to always compare the genuine bill data at the reference position, and therefore the storage capacity for storing the genuine bill data can be made extremely small, which is extremely useful in practice.

[Brief explanation of the drawing]

Figure 1 (A) is a principle block diagram of the moving origin estimation method of the present invention. Figure 1 (B) is a principle block diagram of the paper sheet discrimination system of the present invention. Figure 2 is an embodiment of the present invention. A block diagram of the configuration of the securities identification system. Figure 3 is a flowchart showing the moving origin estimation operation according to the embodiment shown in Figure 2. Figure 4 is an explanatory diagram of measurement data when there is a tear in the security. Figure 5 is FIG. 6, a block diagram of a conventional securities identification system, is an explanatory diagram of the principle of coordinate transformation. In the figure, 104 is a measuring means, 105 is a storage means, 106 is a central processing unit, 107 is a discrimination section, 171 is a genuine bill data recording means, 172 is a comparison means, 200, 500 is a measuring section, 201.501 is an image sensor , 202.502 is an analog-to-digital (A/D) converter, 203.503 is a confirmation section, 210.510 is a central processing unit (CPU), 220.5
20 is a storage unit, 221.521 is a measurement data storage area, 222 is a conversion data storage area, 230.530 is a determination unit, 231.531 is a genuine bill data storage area, 232.532
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Claims (2)

[Claims] (1) determining the equation of a first straight line that includes the first side; determining the equation of a second straight line that is orthogonal to the first straight line and including the second side; A moving origin estimation method that estimates the intersection of and estimates the moving origin. (2) Measuring means (104) for measuring desired physical quantities in each minute region of paper sheets; and storage means (105) for storing the measured values of the physical quantities of paper sheets measured by the measuring means (104). and a central processing unit that estimates a movement origin from the measured values stored in the storage means (105), rearranges the measurement values stored in the storage means (105), and performs coordinate transformation using the movement origin as a reference. (106); genuine bill data recording means (171) for recording genuine bill data that is the result of measuring a genuine bill of the same type as the paper sheet at a certain reference position by the measuring means (104); Comparing means (172) for comparing genuine note data recorded in the note data recording means (171) and transformed data coordinate-transformed by the central processing unit (106);
A paper sheet discrimination system comprising: a discriminating unit (107) for discriminating paper sheets, and configured to estimate a movement origin.