JP2002329164A - Mark decision method and its device and medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a method which decides a mark within a fixed time and makes the decision processing fast even under conditions of variations or the like of pattern, gray level, scraping, dirt reflection factor of the mark, and a mark detection sensor, as long as the mark has clasly partial features of a mark. SOLUTION: A signal waveform obtained by scanning marks (201, 202) formed on the surface of a card 306 by a mark detection part 301 is differentiated twice. Each time the mark waveform is detected, the optimum value of a threshold of binarization is uniquely determined and data of a bit sequence obtained by binarizing the signal waveform by using the threshold are compared with data of a reference bit sequence to decide the marks, thereby making the decision within a fixed time irrelevant to the states variations of the pattern, gray level, scraping, dirt, reflection factor of the marks, of the mark detection sensor, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mark judging method and apparatus for judging the type of a card, such as a prepaid card, a credit card, and an IC card, from a mark provided on the surface of the card, and a medium. Things.

[0002]

2. Description of the Related Art Such a conventional mark judging method includes:
There are the following first to third methods. A first method of calculating a threshold value by calculating a maximum value and a minimum value of data obtained by sampling a mark detection signal waveform;
This method binarizes a mark detection signal waveform using the threshold value, and compares a predetermined number of marks with the number of detected marks, or determines a mark type by comparing a mark length with a reference value. In this method, for example, an average value of the maximum value and the minimum value is used as the threshold value for binarization. If the mark type cannot be determined in one determination, the threshold value is calculated again. It is general to improve the reliability of the determination by performing a series of processes including correction, binarization, and determination a predetermined number of times. The second method is a method of comparing a mark detection signal waveform with each of a plurality of reference waveforms stored in advance, and reading mark position information from a reference waveform having the highest correlation with the mark detection signal waveform. This method is mainly used when precise mark positioning is required in the field of an exposure apparatus. The third method is a method of determining a mark from the number of edges and the distance between edges of a waveform obtained by performing first-order differentiation processing on a mark detection signal waveform.

[0003]

However, the above-mentioned first conventional mark determination method has the following problems. -The threshold for binarization of the mark detection signal waveform is not uniquely determined, the threshold is appropriately analogized from the maximum value and the minimum value, and the number of trials is increased because the determination is performed by repeating the trial several times. In such a case, there is a problem that the determination time becomes longer. This indicates that when the mark determination must be performed in combination with an apparatus having a transport mechanism, the determination may not be completed within the allowed time, which is a problem. -Depending on the density of marks, rubbing, dirt, differences in reflectance, or variations in the sensitivity of mark detection sensors, etc.
In some cases, the threshold value obtained from the maximum value, the minimum value, etc., does not always succeed in binarization, although there is a clear mark feature, and there is a problem that a determination error occurs. -In the case where judgment is made from the management of the number of marks and the mark length as a result of scanning the binarized data from the beginning of the data, measurement errors and mark length errors are likely to accumulate, There is a problem that determination accuracy is ambiguous and it is difficult to manage and specify a determination range, for example, there is a possibility that a non-mark is recognized as a mark.

[0004] The second conventional mark determination method is useful for precise positioning, but since the measurement accuracy depends on the amount of the reference waveform stored in the memory, a large-capacity memory is required for the device, and the mark can be deleted. When the scanning time is limited, there is a problem that the restriction on the apparatus side is large, such as the necessity of a CPU (Central Processing Unit) capable of high-speed processing. Especially the mark is not for alignment,
When used only for specifying the type of the object on which the mark is applied from the mark shape or pattern, a large-scale device is unnecessary, and there is a problem that it is not suitable for the technical field to which the present invention belongs.

In the third conventional mark determination method, if the signal waveform has irregularities due to differences in the shading, rubbing, smearing, reflectance, etc. of the mark, there is a possibility that a signal which is not originally an edge may be recognized as an edge. However, there is a problem that a determination error occurs depending on the error and the accumulation of the error of the distance between edges, which is not suitable for the technical field to which the present invention needs to perform determination while allowing mark deterioration.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. The first object of the present invention is to solve the problems such as mark patterns, shading, rubbing, dirt, reflectance, and variations in mark detection sensors. Judgment can be made within a certain time regardless of
It is another object of the present invention to provide a mark determination method that can speed up the determination process.

A second object of the present invention is to provide a mark having a partially distinctive mark characteristic even under conditions such as a mark pattern, shading, rubbing, dirt, reflectance, and variations in a mark detection sensor. It is another object of the present invention to provide a mark determination method that improves the determination rate by performing the determination.

A third object of the present invention is to easily manage the judgment accuracy and error without accumulating measurement errors and mark length errors.
An object of the present invention is to provide a mark judgment method for improving the judgment rate by specifying the mark.

A fourth object of the present invention is to provide the above-described first to third aspects.
In order to realize the object of the present invention, it is an object of the present invention to provide a mark determination device which can determine the type of a marked object by performing a mark determination with a simple configuration and a novel method.

[0010] A fifth object of the present invention is to provide a medium including a program which, when realizing the fourth object, can cause a mark determination device to process according to a procedure determined toward realizing each of the above objects. It is in.

[0011]

According to the mark determination method of the present invention, a mark provided on an object is scanned by a mark detection means,
In a mark determination method for determining the type of the object by determining the mark from a signal obtained by scanning, a signal waveform of the signal is differentiated twice, and each time a mark waveform is detected, a threshold value for binarization is obtained. Is uniquely determined, and the mark is determined by comparing the bit string data obtained by binarizing the signal waveform with the reference bit string using the threshold value. According to this, the determination can be performed within a fixed time regardless of the state of the mark pattern, shading, rubbing, smearing, reflectance, variation of the mark detection sensor, and the speed of the determination process can be increased. In addition, even under conditions such as mark patterns, shading, rubbing, dirt, reflectance, and variations in mark detection sensors, the determination rate can be improved by making a determination if the mark has a partly clear mark characteristic. It will be possible.

In the mark judging method according to the present invention, the reference bit string includes one corresponding to a maximum allowable value of the mark width and one corresponding to a minimum allowable value of the mark width. By comparing the measured data obtained, the mark is determined while managing the determination accuracy and error. According to this, the judgment accuracy and the error can be easily managed and designated without accumulating the measurement error and the mark length error, and the judgment rate can be improved.

Further, the mark determination device of the present invention comprises a mark detection means for optically detecting a mark on an object,
Transport means for transporting the object to scan the mark at the time of mark detection, and twice differentiating the detection signal waveform detected by the mark detection means during the transport of the object by the transport means to detect a mark waveform. In each case, the optimum value of the threshold value for binarization is uniquely determined, and the type of the mark is determined by comparing the bit sequence data obtained by binarizing the signal waveform with the reference bit sequence using the threshold value. And a control unit for determining the type of the object from the type of the mark determined by the determination unit. According to this configuration, it is possible to determine the type of the object that has been marked during the transportation by the transportation unit.

Further, in the mark judging device according to the present invention, the reference bit string is composed of two types, one corresponding to the maximum allowable value of the mark width and the other corresponding to the minimum allowable value of the mark width. By comparing the measured data with the measured data, the mark is determined while managing the determination accuracy and error. According to this configuration, the judgment accuracy and the error can be easily managed and specified without accumulating the measurement error and the mark length error, and the judgment rate can be improved.

Further, the mark judging device of the present invention further comprises a signal converting means for converting the detection signal detected by the mark detecting means into a digital signal, and the judging means comprises a digital signal converted by the signal converting means. The configuration is provided with means for obtaining a waveform from which noise has been removed by filtering a signal waveform. According to this, mark determination can be performed from an ideal waveform from which noise has been removed by filtering.

Further, the medium of the present invention provides a mark detection process for optically detecting a mark on an object by scanning the mark with mark detection means, and twice differentiating a signal waveform obtained in the mark detection process. The computer sequentially executes a double differentiation process of binarizing to obtain a binary bit sequence, and a mark determination process of comparing the bit sequence data binarized by the double differentiation process with a reference bit sequence to determine the mark. This is a configuration including a program for causing the program to execute. According to this, it is possible to realize a mark determination method and apparatus capable of easily managing and specifying the determination accuracy and error without accumulating the measurement error and the mark length error and improving the determination rate.

Also, the medium of the present invention is a mark detection process for optically detecting a mark provided on an object by scanning the mark with mark detection means, and a filter process for a mark detection signal detected in the mark detection process. Noise removal processing for removing noise, double differentiation processing for differentiating the signal waveform obtained in the mark detection processing twice and binarizing to obtain a binary bit string, and binarization in the double differentiation processing The program includes a program for causing a computer to sequentially execute a mark determination process for determining the mark by comparing the data of the bit sequence with a reference bit sequence. According to this,
A mark determination method and apparatus capable of easily managing and specifying the determination accuracy and error and improving the determination rate without accumulating the measurement error and the mark length error can be realized.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment of the present invention, a case where two types of cards, that is, a card A 306 shown in FIG. 2 and a card B 306 shown in FIG. 3 are determined will be described as an example. Instead, it may be something other than a card. At substantially the same position on one surface of the card A 306 and the card B 306, a mark 201 and a mark 202 are provided by printing or the like.
One card is classified into A and B respectively. That is, the mark 201 attached to the card A 306 has a length L
The mark 202 attached to the card B306 is composed of a black mark portion 201a having a length L2, a black portion 201b having a length L3, and a black mark portion 201a having a length L3. L5 and a black mark portion 202b of length L6.

FIG. 1 is a block diagram showing a configuration of a card type determining apparatus shown as an embodiment of the present invention. A card type determination device 300 in FIG. 1 includes a mark detection unit 301 for detecting marks (201, 202) provided on the surface of a card 306, and converts an analog waveform detected by the mark detection unit 301 into a digital signal. A for conversion
/ D conversion unit 302, a determination unit 303 for determining the type of the card 306 based on the digital signal converted by the A / D conversion unit 302, and a card unit 306 disposed immediately below the mark detection unit 301. A transport unit 304 for transporting;
A control unit 305 that controls the transport of the card 306 based on the determination result of the determination unit 303.

The mark detection section 301 detects the marks 201 and 202 provided on the card 306, and can be realized by, for example, a reflection type infrared photoelectric sensor. When the card 306 is inserted into a predetermined card insertion slot (not shown), the card is conveyed directly below the mark detection unit 301 by the conveyance unit 307, and the marks (201, 202) are scanned by the mark detection unit 301 for marks. . Mark detector 3
01 is converted into a digital signal by the A / D conversion unit 302 and input to the determination unit 303.
At 03, the type of the mark is determined and the type of the card 306 (card A, card B) is specified. The control unit 305 is, for example, a personal computer equipped with a CPU, which controls the operation of the entire apparatus, changes the transport speed according to the type of the card 306, or sets the mark 20 on the card 306.
1. If none of the marks 202 is given, the controller 307 instructs the transport unit 307 to pull back the card 306. The control unit 305 controls the entire apparatus according to a predetermined procedure according to a program incorporated in a storage unit (not shown) in advance.

FIG. 4 shows a program incorporated in the storage unit, which causes the control unit 305 to operate the card type determination device 3.
6 is an operation flowchart illustrating a processing procedure for controlling 00. The processing procedure will be described next according to the flowchart.

When the card 306 is inserted into a predetermined card insertion slot and conveyed by the conveying unit 307 directly below the mark detecting unit 301, the marks (201, 202) are scanned to start the mark detection. The signal scanned by the mark detection unit 301 is digitized by the A / D conversion unit 302. In step ST100, noise is removed from the mark detection signal waveform digitized by the A / D conversion unit 302 by a filtering process using a moving average or the like.
FIG. 5 is a diagram showing an example of an ideal signal waveform obtained after filtering the mark detection waveform. FIG. 6 is a diagram showing an example of an actual signal waveform obtained after filtering the mark detection waveform. 5 and 6, the ordinate represents the intensity of the A / D-converted signal (unit is, for example, dB), and the abscissa represents the card 3 that has performed the mark detection.
06 (for example, X coordinate). If the mark is in a good state, an ideal waveform as shown in FIG. 5 can be obtained.
There is a possibility of obtaining a distorted waveform as shown in FIG. In FIG. 6, an area denoted by reference numeral 501 is a mark part 201a of the mark 201, and a reference numeral 502 is a mark part 201b.
, Respectively.

Here, according to the conventional method, the data is binarized by appropriately calculating a threshold value from the maximum value and the minimum value of this signal. However, as shown in FIG. If there is a difference in density between the mark portion 201a and the mark portion 201b, the waveform heights in the region 501 and the region 502 are not uniform, and as a result, it is impossible to make a determination while clearly having mark characteristics. There was a problem. In addition, there is a method of performing a first differentiation process on a detection signal waveform to determine a mark from the number of edges of the waveform and the distance between edges. However, as shown in an area 503, the signal waveform has irregularities due to mark contamination. In such a case, there is a possibility that an edge that is not originally an edge may be recognized as an edge, or a determination error may occur depending on the accumulated error of the distance between edges.

Therefore, in the present invention, step ST1
00 for the signal waveform obtained in step ST101.
Is subjected to double differential processing. Here, the double differentiation processing is performed according to the following equation (1).

Y (i) = {x (i) −x (i + Δd1)} − {x (i + Δd2) −x (i + Δd1 + Δd2)} {Equation (1)

Here, x (i) is the i-th data of the signal waveform obtained in step ST100, y (i) is the i-th double differential value, １d1 and △ d2 are the first derivative and the second derivative, respectively. Data interval for differentiation.

FIG. 7 shows the result of performing a double differentiation process on the signal waveform of FIG. In FIG. 7, the vertical axis represents the intensity of the digital signal subjected to the double differentiation processing (unit is, for example, d
B), and the horizontal axis represents the card 306 that has performed mark detection.
Represents an upper position (for example, X coordinate). As is clear from FIG. 7, the distortion of the waveform as shown in FIG. 6 is removed by the double differentiation process, and the binarization can be performed using 0 as a threshold value.

The binarization is performed as a bit conversion process in step ST102. That is, in the above equation (1), the bit is turned on if y (i) is positive, and turned off if y (i) is negative. Steps ST101 and ST102
Is repeated by the number of data samples to obtain a binary bit string (step ST103).

A bit string Mark resulting from performing the above-described processing on the data of FIG. 6 will be described below as an example. Where 1
The bit interval becomes the resolution for scanning the mark, and its value corresponds to a value obtained by dividing the total mark length L1 + L2 + L3 by the number of data samples.

Mark = 00007FFFFFFFFF00000000FFFFFF80000000 {Formula (2)}

The bit data thus obtained is:
In step ST104, the first mark is determined. In the mark determination process of step ST104, the reference bit string of the corresponding mark is stored in the maximum allowable value T_max and the minimum allowable value T_min, and the bit string obtained in step ST103 and the two reference bit strings T_max, T_min are stored. Compare with.

For example, the mark 201 is used as the first mark.
T_max, T of the mark 201
Assuming that _min is defined as in the following expressions (3) and (4), the mark determination process in step ST104 is realized by the following expressions (5) and (6). That is, if the detection data Mark satisfies the equations (5) and (6) simultaneously, the mark 201 is determined. Here, & indicates an AND operation of a bit operation.

T_max = 03FFFFFFFF00007FFFFFFFFFFF8FF FFF {Equation (3)

T_min = 0001FFFE00000003FFFFFFF00000 000 {Equation (4)

(Mark & T_min) == T_min (5)

(Mark & T_max) == Mark {Equation (6)

As is apparent from equations (5) and (6), high-speed processing can be expected because mark determination can be performed only by bit operation. In addition, when a determination error occurs, there is no repetitive processing for recalculating the threshold, so that determination can be made within a fixed time regardless of the mark pattern or shape. Further, since the determination range can be clearly specified in units of the resolution at which the mark is scanned, setting of the determination accuracy and error management become easy. For example, in the determination of the mark 201,
If dirt is allowed in the white plain region L2 between the mark portion 201a and the mark portion 201b, it is only necessary to newly change T_Max shown in Expression (3) to a value shown in Expression (7).

T_max = 03FFFFFFFFFFFFFFFFFFFFFFFF8FF FFF ‥‥‥ (Equation 7)

By adopting such a method, it is possible to avoid the occurrence of a determination error due to the accumulation of errors, as compared with a case in which a plurality of marks are measured separately and their lengths are determined.

If the detection data simultaneously satisfies the formulas (5) and (6) in step ST105, the determination is completed as the mark 202. If not, the process proceeds to step ST106 as another mark.

In step ST106, T_max and T_min corresponding to the mark 202 are newly defined, and a determination is made by the equations (5) and (6) as in the step ST104 (step ST7). If it is neither the mark 201 nor the mark 202, it is determined that there is no corresponding mark, and the determination ends.

[0042]

As described above, according to the present invention, the threshold value for binarization is uniquely determined by differentiating the signal waveform twice, and the signal waveform is binarized using the threshold value. Since the mark is determined by comparing the data with the reference bit string, regardless of the state of the mark pattern, shading, rubbing, dirt, reflectance, mark detection sensor variation, etc.
The determination can be made within a certain time. In addition, it is possible to speed up the determination process, and even if the mark has partially distinctive mark characteristics even under conditions such as mark pattern, shading, rubbing, dirt, reflectance, and variation in the mark detection sensor. By performing the determination, the determination rate can be improved. Furthermore, a mark determination method and apparatus having an excellent effect that a measurement error and a mark length error do not accompany accumulation, and a determination accuracy and an error can be easily managed and designated, thereby enabling an improvement in a determination rate. Can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a card type determination device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a card A in the present embodiment.

FIG. 3 is a schematic configuration diagram of a card B in the present embodiment.

FIG. 4 is a flowchart showing the operation of the card type determination device according to the embodiment.

FIG. 5 is a diagram showing an example of an ideal signal waveform obtained after filtering a mark detection waveform.

FIG. 6 is a diagram showing an example of an actual signal waveform obtained after filtering a mark detection waveform.

FIG. 7 is a signal waveform diagram obtained after performing a double differentiation process on the signal waveform of FIG. 6;

[Explanation of symbols]

 201 mark 202 mark 300 card type determination device 301 mark detection unit 302 A / D conversion unit 303 determination unit 304 transport unit 305 control unit 306 card

Claims (7)

[Claims] 1. A mark determination method for scanning a mark on an object by mark detection means and determining the mark from a signal obtained by scanning to determine the type of the object, wherein a signal waveform of the signal is By differentiating twice, each time a mark waveform is detected, an optimal value of a threshold value for binarization is uniquely determined, and the data of the bit sequence obtained by binarizing the signal waveform using the threshold value is compared with a reference bit sequence. A mark determination method, wherein the mark is determined. 2. The reference bit string is composed of one corresponding to a maximum allowable value of a mark width and one corresponding to a minimum allowable value of the mark width. By comparing both allowable values and measurement data obtained by the scanning, 2. The mark judging method according to claim 1, wherein said mark is judged while managing judgment accuracy and error. 3. Mark detection means for optically detecting a mark on an object, conveyance means for conveying the object to scan the mark upon detection of the mark, and conveyance of the object by the conveyance means During the detection, the detection signal waveform detected by the mark detection means is differentiated twice, and each time a mark waveform is detected, an optimum threshold value for binarization is uniquely determined. Determining means for determining the type of the mark by comparing the data of the coded bit string with a reference bit string; andcontrol means for determining the type of the object from the type of the mark determined by the determining means. A mark determining device. 4. The reference bit string is composed of two types, one corresponding to the maximum allowable value of the mark width and the other corresponding to the minimum allowable value of the mark width, and the determination means compares the two allowable values with the measured data. 4. The mark determination device according to claim 3, wherein the mark is determined while managing determination accuracy and error. 5. A signal conversion device for converting a detection signal detected by the mark detection device into a digital signal, wherein the determination device performs a filtering process on a digital signal waveform converted by the signal conversion device to reduce noise. 4. A means for obtaining a waveform from which noise has been removed.
Or the mark judging device according to 4. 6. A mark detection process for optically detecting a mark provided on an object by scanning the mark with mark detection means, and a signal waveform obtained in the mark detection process is differentiated twice to be binarized and binary. And a mark determination process of comparing the bit sequence data binarized by the double differentiation process with a reference bit sequence to determine the mark. Including medium. 7. A mark detection process for optically detecting a mark on an object by scanning the mark with mark detection means, and a noise removal for filtering a mark detection signal detected in the mark detection process to remove noise. Processing, double differentiation processing to obtain a binarized bit string by differentiating the signal waveform obtained in the mark detection processing twice and binarizing, and based on the bit string data binarized by the double differentiation processing A mark determination process for determining the mark by comparing with a bit sequence.