JPH0528626A - Card reader - Google Patents

Abstract

PURPOSE:To prevent the generation of a reading error by changing a bar-code on a card to an electric positional data and reading it while correcting a positional shift every one bit. CONSTITUTION:This reader is constituted of a position detector 22 for integrating pulses corresponding to the moving distance of the card and generating the positional data of the card, an edge detector 23 for generating a first interrupting signal 25 to a microcomputer 21 by detecting the edge of the rising and falling of a bar-code signal, an interruption generating circuit 27 for generating a second interrupting signal 26 when a position is set beforehand and the positional data of the card become equal and a RAM 24 for temporarily storing data. The positional data when the first interrupting signal 25 is generated is stored in the RAM 24 and depending on whether the positional data is stored in the RAM 24 or not when the second interrupting signal, 26 is generated, whether the bar-code is 1 or 0 is decided and the logical position of a next bar is calculated from the positional data stored in the RAM 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a card reader for reading and processing information on a prepaid card or a premium card.

[0002]

2. Description of the Related Art In many cases of prepaid cards and premium cards, a bar code is provided on the card for the purpose of preventing forgery of the card. FIG. 5 shows an example of the structure of the card, in which a bar code 2 composed of m (m is an integer) line segments (hereinafter referred to as a bar) is formed on the card 1. The bar pitch is P or 2P. When a center line is drawn at a constant pitch P, data 1 indicates that there is a bar on the center line, data 0 indicates that there is no bar on the center line, and 1101 ... It composes the bar code data of ...

Conventionally, the bar code 2 on the card is detected,
The bar code detecting circuit for generating a pulse corresponding to the bar code had a structure as shown in FIG. 6 (a).
Further details will be described with reference to FIGS. 6A, 6B, 7 and 8. In FIG. 6A, 3 is a sensor,
Reference numeral 4 is an amplifier, and 5 is a binarization circuit. For the sensor 3, a magnetic detection element, an optical detection element, or the like is used corresponding to the bar code on the card, and various methods such as a contact type and a non-contact type are adopted.

FIG. 6B is a bar code signal waveform diagram showing an example of the output signal of the bar code detecting circuit. Corresponding to each bar, the signal changes only where the bar is. When the sensor 3 in FIG. 6A makes relative movement along the bar code on the card at a constant speed, the signal interval corresponding to each bar is a constant time T or 2T.

FIG. 7 shows a bar used in a conventional card reader for converting the bar code signal shown in FIG. 6 (b) into a bit string of 0 and 1 and generating bar code data having a predetermined bit length. It is a block diagram which shows the structure of a code recognition means. A ROM (Read Only Memory) 6 in which a program is stored, a microcomputer 7 that performs processing according to the contents of the ROM 6, a counter 8 that accumulates clock pulses of a constant cycle, a rising edge of a bar code signal shown in FIG. An edge detector 9 that detects a falling edge and generates an interrupt signal to the microcomputer 7, a RAM (random access memory) 10 that stores data of the counter 8 at the time of rising and falling of the barcode signal, and It is configured to include.

FIG. 8 shows a flow chart of a program stored in the ROM 6. The operating principle of the conventional barcode recognition means will be described below with reference to this drawing. However, the card and the sensor 3 first move relative to each other, and the count values at the rise or fall of all bar code signals are stored in the RAM.
10 is stored.

In process 11, n stored in the RAM 10 is stored.
The center value B of the signal using the rising data and the falling data of the th bar code signal (n is an integer)
Calculate n. The central value Bn at this time is an integrated amount of clock pulses of a constant cycle, and the unit is time. In process 12, the central value Bn calculated in process 11 is set to R
Save to the specified address of AM10. Then, the address is updated. In the processing 11 to 12, the branch 1
3, the central value Bn of the m bars is calculated,
Repeated until 10 is stored. The process 14 is a step of calculating the time Tn between the bars, and Bn
-Calculate Bn-1. Whether the nth barcode signal is 1 or 0 depending on the value of Tn in the branches 15 and 16.
Is determined. If Tn satisfies the following equation T / 2 ≦ Tn <3T / 2, the nth data is set to 1, and if 3T / 2 ≦ Tn <5T / 2 is satisfied, the nth data is set to 0.

By thus providing the Tn judgment standard with a wide range, the accuracy of reading the bar code is improved.
Processing 17 and processing 18 are for storing the n-th data determined to be 1 or 0 in the RAM in order from the lower bit.

By repeating the above processings 14 to 18 (m-1) times, m bars are converted into an m-bit digital code. However, only for the first bar,
Since there is no bar in front, the above processing cannot be performed, so it is processed separately.

[0010]

However, in such a conventional example, in the ideal case where the card conveying speed is constant and there is no speed jitter, correct bar code detection can be performed by the above-mentioned method. In an actual card reader, there are slippage of the card feed roller and transport system, speed jitter due to load fluctuation, speed fluctuation due to ambient temperature change, etc.
As a result, the judgment of 1 and 0 on the barcode may be mistaken.

However, in the above-mentioned conventional bar code recognition means, since the method of counting the clock pulses of a constant period irrelevant to the actual movement of the card is used,
The reading performance greatly depends on the accuracy of the card transportation speed, and reading errors are likely to occur due to fluctuations in the transportation speed. Further, if the count value shifts midway due to slippage of the transport system, the error is accumulated, and the longer the movement distance (the larger the number of bits of the barcode, the more likely it is that a detection error will occur. Had a point.

The present invention solves the above-mentioned conventional problems, and causes a bar code detection error even when the card feed roller in the card reader and the conveyance system are slipped, and the conveyance system has uneven speed and fluctuations in speed. It is intended to provide a non-card reader.

[0013]

In order to achieve the above object, a card reader of the present invention comprises a sensor for detecting a bar code on a card composed of a plurality of line segments having two kinds of pitches and having a constant width. A bar code detecting means for amplifying the output of the sensor and converting it into a pulse; a position recognizing means for detecting the position of the card and outputting position data; and a first interrupt for detecting a rising edge and a falling edge of the pulse. The edge detecting means for generating a signal, and the second when the preset position data and the position data become equal
Interrupt generating means for generating the interrupt signal, storage means for temporarily storing data, and position data when the first interrupt signal is generated are stored in the storage means,
When the second interrupt signal is generated, it is determined whether the bar code data is 1 or 0 depending on whether or not the position data is stored in the storage means, and the next bar is read from the position data stored in the storage means. The barcode is read while performing correction for each bit by an arithmetic processing unit programmed to calculate a theoretical position.

[0014]

According to the above structure, when the card transport speed changes, the time interval of the pulse output from the bar code detecting means changes, but the bar position interval using the position data for detecting the card position is changed. Is always constant and is not affected by speed fluctuations. Also, since the theoretical position of the bar to be detected next can be calculated from the position data of the bar detected earlier, the position can be corrected bit by bit, so that it is possible to use the actual position due to slippage during card transportation. Even if an error occurs between the position and the position data, the error is not accumulated and the reading reliability can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the bar code recognizing means used in the card reader of the present invention. The bar code signal shown in FIG. 6 (b) is converted into a bit string of 0 and 1. A bar code with a specified bit length
It generates data.

In FIG. 1, 20 is a ROM that stores a program that realizes the barcode recognition method that is a feature of the present invention, 21 is a microcomputer that executes processing in accordance with the contents of the ROM 20, and 22 is the movement distance of a card. Position recognition means for accumulating the generated pulses and generating the position data of the card, and 23 detects the rising or falling edge of the bar code signal shown in FIG. 6B and generates the first interrupt signal 25 to the microcomputer 21. An edge detector 24, a RAM 24 for storing the position data output from the position recognizing means 22 at the rising and falling edges of the bar code signal, and a microcomputer 27 when the preset position data and the card position data match. 21 is an interrupt generating means for generating a second interrupt signal 26 .

FIG. 2 is a block diagram of an embodiment for realizing the position recognizing means 22. 28 is a motor for card transportation, 29 is a coaxially mounted motor 28, and a tacho generator (hereinafter referred to as TG) that outputs a sinusoidal signal corresponding to the rotation angle of the motor 28, and 30 is a TG.
A binarization circuit that amplifies the sinusoidal position signal of 29 to generate a rectangular wave position pulse, and 31 is an integrating counter that integrates the position pulse and generates the position data of the card. Motor 2
The rotation of 8 is transmitted to the card transport roller by a pulley, a belt or the like. The amount of movement of the card carried by the card carrying roller is proportional to the amount of rotation of the carrying roller, and finally proportional to the amount of rotation of the motor 28. Therefore, the TG 29, which rotates simultaneously with the motor 28, indirectly outputs a signal proportional to the movement amount of the card.

FIG. 3 is a bar code signal waveform diagram showing an example of the output signal of the bar code detecting circuit shown in FIG. 6 (a), and is a diagram for explaining the operation principle of the present invention. Figure 6
When the sensor 3 shown in (b) performs relative movement along the bar code on the card, the interval between the signals corresponding to each bar should be calculated by integrating the number of position pulses output from the binarization circuit 30. Can be known as distance data,
A constant distance X or 2X is obtained.

FIG. 4 shows a flow chart of a program stored in the ROM 20. The operating principle of the barcode recognition means used in the card reader of the present invention will be described below with reference to FIGS. 3 and 4.

Process 40 is the edge detector 23 shown in FIG.
Is a first interrupt processing routine generated by the output of the RAM 24, and the position data of the position recognizing means 22 is stored in the RAM 24 at the rising or falling timing of the bar code signal.
Store to the address specified by. After that, the address is updated. The process 41 detects the rising or falling of the bar code signal and sets 1 to the process flag indicating that the position data has been processed.

The processes 42 to 51 are executed by the interrupt generating means 27.
It is a second interrupt processing routine generated by. The process 42 calculates the center position Xn of the signal shown in FIG. 3 using the rising data and the falling data of the n-th barcode signal (n is an integer) stored in the RAM 24. Process 43 is a routine for setting the next interrupt generation condition in the interrupt signal generation means 27, and n +
To process the first bar code signal, set the card position Xi at which the interrupt should be generated. Position Xi
Is calculated by Xi = Xn + 3X / 2.

The branch 44 checks the processing flag. If the processing flag is 1, the branch is taken. If the processing flag is 0, the processing 45 is carried out.
Branch processing to. The process 45 is a routine for setting 0 to the n-th data bit. When the processing flag is 0, it indicates that the rising or falling of the barcode signal has not been detected. Branch 46 and branch 4
Reference numeral 7 is a routine for checking whether or not the detected bar code is in conformity with the specified format, so that different kinds of cards are not processed by mistake. Specifically, whether the position data at the rising edge and the position data at the falling edge of the n-th barcode signal are within the width formed by the threshold values a and b of the data shown in FIG. To check. If it is within the width, it is determined that the card has the specified format, and the process 48 is branched. If it is not within the width, it is regarded as out of the specified format, and error processing is performed in process 49. The process 48 is a routine that sets 1 to the n-th data bit. Process 5
0 is the theoretical center position Xr of the (n + 1) th barcode
Is a routine for calculating
Based on the actually measured center position Xn of the n-th bar code calculated in step 1, the bar pitch X on the card is added thereto.

The Xr = Xn + X processing 51 is a routine for calculating the threshold values a and b for the (n + 1) th bar code data, and a new threshold value of positive and negative constant width is centered on the theoretical center position Xr. Calculate a and b.

The above is the processing for one bit of the bar code, and similarly, the processing is repeated for the number of bars, and
By determining 1 or 0 for each bit and arranging in order from the lower bit, bar code data can be obtained.

In the embodiment of the present invention configured as described above, since the position information of the card is used for detecting the bar code, the fluctuation of the card conveying speed corresponding to the ambient temperature, which has been a problem in the past, is caused. Even if there is, stable barcode detection is possible regardless of fluctuations. Also, process 5
As shown in 0, in order to read the (n + 1) th bar, the theoretical center position is calculated with reference to the actually measured center position of the nth bar, and therefore the count value in the middle due to slippage of the transport system or the like. Even if the (position data) shifts, the shift is corrected bit by bit, and the accumulation of errors, which has been a problem in the conventional example, does not occur. Therefore, even in the case of a bar code with many bits (the relative movement distance between the sensor and the card is long),
Stable bar code detection is possible regardless of the number of bits.

[0027]

As is apparent from the above description, the card reader of the present invention prevents the occurrence of a reading error with respect to the change of the card transport speed by using the position recognition means for reading the bar code. It is also effective for the above, and by using the arithmetic processing means for calculating the theoretical position of the next bar from the reading result of the current bar for each bit, a read error occurs even when the transport system slips or the like. It is effective to prevent the above, and as a result, the barcode reading error can be significantly reduced, and a stable and highly reliable card reader can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of bar code recognition means used in a card reader of the present invention.

FIG. 2 is a block diagram of a position recognition unit in the same embodiment.

FIG. 3 is a bar code signal waveform diagram for explaining bar code recognition in the card reader of the present invention.

FIG. 4 is a flow chart of a program in one embodiment of the card reader of the present invention.

FIG. 5 is a structural diagram of a card for explaining a barcode.

6A is a block diagram of a conventional bar code detection circuit, and FIG. 6B is a bar code signal waveform diagram for explaining the principle of a conventional bar code reader.

FIG. 7 is a block diagram of a conventional barcode recognition means.

FIG. 8 is a flow chart of a program in a conventional card reader.

[Explanation of symbols]

20 ROM 21 Microcomputer (arithmetic processing means) 22 Position recognition means 23 Edge Detector (Edge Detection Means) 24 RAM (storage means) 25 First interrupt signal 26 Second interrupt signal 27 Interrupt generation means

Claims (2)

[Claims] 1. A sensor for detecting a bar code on a card composed of a plurality of line segments having two kinds of pitches and having a constant width,
A bar code detecting means for amplifying the output of the sensor and converting it into a pulse, a position recognizing means for detecting the position of the card and outputting position data, and a first interrupt signal for detecting a rising edge and a falling edge of the pulse. An edge detecting means for generating an interrupt, an interrupt generating means for generating a second interrupt signal when preset position data and the position data become equal, a storage means for temporarily storing the data, and a first interrupt The position data when the signal is generated is stored in the storage means, and whether the bar code data is 1 or 0 is determined depending on whether the position data is stored in the storage means when the second interrupt signal is generated. An arithmetic processing means programmed to perform a theoretical position of the next bar from the position data stored in the storage means Card reader with. 2. A position recognition means for detecting the position of a card and outputting position data, a card conveying motor, a rotation angle signal generating means for generating a signal according to the rotation angle of the motor, and a rotation angle of the motor. The card reader according to claim 1, further comprising means for accumulating signals according to the above.