JPH0315792B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic ink character recognition method.

The magnetic ink character recognition method involves dividing the data on the amount of magnetic change of the magnetic ink characters into a predetermined number of parts, detecting the positions of each divided area where the positive peak and negative peak correspond to each other, and identifying the positive code and the negative value. There is a method of recognizing read characters by creating a code and comparing this character code consisting of a plus code and a minus code with a specified character code. However, with this method, any magnetic ink character is 1
Although only one peak appears in each divided area, abnormal peaks occur due to bleeding of magnetic ink characters, etc., and a positive peak and a negative peak coexist within one divided area. magnetic ink characters cannot be recognized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic ink character recognition method that can improve the above-mentioned drawbacks and can perform character recognition even when two peaks overlap in one divided area due to abnormal peaks.

The present invention will be described in detail below with reference to the drawings.

The present invention will be explained with reference to FIG. 1. Data on the amount of magnetic change of magnetic ink characters is divided into a predetermined number of blocks, and it is detected to which block each position of a positive peak and a negative peak corresponds. A plus code and a minus code are created, and the read character is recognized from the character code made up of these two codes. and 2 in the same block
When two peaks overlap, one of them is excluded, two types of character codes are created, and the read characters are recognized.

FIG. 2 shows an example of an apparatus used to carry out the invention.

In this example, magnetic ink characters (E13B) are read and recognized from a medium such as a card such as a check on which magnetic ink characters (E13B) are recorded at regular intervals in the horizontal direction. When a read command is input from an external terminal device etc. via the interface 12 and peripheral interface adapter (hereinafter referred to as PIA) 13, the PIA is in a ready state.
It is displayed on the display circuit 15 via 14.
When a card having magnetic ink characters is inserted into the entrance in this state, this card is detected by the sensor 16. MPU11 is from sensor 16
When the card detection signal is sensed through the PIA 14, the motor control circuit 17 is actuated through the PIA 14 to rotate the motor at a constant speed, causing the motor to feed the card horizontally at a constant speed, and the display circuit 15 Show that it is running. A magnetic reading head 18 scans the card in fixed position relative to the card at a constant speed to read the magnetic ink characters. The read signal from the magnetic head 18 becomes a differential waveform representing the amount of magnetic change, is amplified by an amplifier 19, passes through a low-pass filter 20 to remove noise, and is converted into a digital signal by an analog/digital converter 21. The MPU 11 converts the digital signal from the analog/digital converter 21 into the PIA 14.
At a predetermined time interval (one character is divided into 8 blocks in the card feeding direction, 1 block is divided into 8 blocks)
The data is captured at random access memory (time interval corresponding to the sampling time) and then stored in random access memory (hereafter
RAM) 22, the read characters are recognized by performing the processing described below, and the recognized characters are
The data is output to an external terminal device or the like via the PIA 13 and the interface 12 for display or predetermined processing.

MPU11 is read-only memory (hereinafter referred to as
Predetermined processing is performed according to the program in the ROM (ROM) 23, but the main processing is specifically carried out by the third
This is carried out as shown in FIGS. That is, when the card is running, as shown in FIG. 3, digital signals from the analog/digital converter 21 are read at the above-mentioned time intervals and are sequentially stored in consecutive addresses of the read buffer (RBUF) in the RAM 22 as read data. After reading all the read data for one card and storing it in the RAM 22, character recognition starts. First, in order to detect the starting point of one character from the read data, the beginning of the character is detected and the recognition of that character is performed. start. A positive peak value and its address, and a negative peak value and its address are detected from the data of one character in the read data (data for one character from the beginning of the detected character) and are stored separately in the RAM 22. Create a plus table (PTB) and a minus table (MTB). As shown in FIG. 8, the RAM 22 is allocated with a read buffer (RBUF) in which read data is stored, a PTB, an MTB, a plus peak table (PPTB), a minus peak table (MPTB), etc. Then PTB,
The contents of MTB are rearranged in descending order of peak value and stored in PPTB and MPTB (in this example, the first plus peak value of PTB and its address are stored first in PPTB without being rearranged).
Character codes are created from the contents of PPTB and MPTB in order of the largest peak value, two or three at a time (addresses in RBUF, not PPTB and MPTB), and stored in the code table of the RAM 22. In this case, the plus peak address and the minus peak address are the plus peak and minus peak positions of the read waveform obtained from the magnetic head 18 when the magnetic ink characters are scanned by moving the card and read by the magnetic head 18. Since they are compatible, the character code can be determined by creating a plus code and a minus code by looking at how many blocks are separated between the first plus peak address, other plus peak addresses, and minus peak addresses. Create and store in code table. However, the magnetic ink characters are constructed so that the first plus peak appears in every character in the first block. Next, when a plus peak and a minus peak overlap in the same block, a plus code is recreated by invalidating the plus peak of the two duplicated peaks. By creating a character code of 1 and re-creating the negative code by invalidating the negative peak of the two duplicated peaks, a second character code consisting of this negative code and the first positive code created above is created. Create a character code for . Originally, peaks are not duplicated in any character in one block, and if two peaks overlap in the same block, it is highly likely that one of them is an abnormal peak. Therefore, there is a high possibility that either the first character code or the second character code is the correct character code.
Next, the above character code is compared with a plurality of fixed codes pre-stored in the fixed code table of the ROM 23, and if it matches any fixed code, the read character is recognized as a character of that code.
If it does not match any of the fixed codes, it will be considered unrecognizable and the character “?” will be added to it.
The read data is set in the RAM 22, and each character is sequentially recognized from the read data in the same manner.

FIG. 4 is a flowchart specifically showing the portion of FIG. 3 in which character beginning detection and peak detection are performed. The start of the data is detected by sequentially reading the read data from the RBUF, i.e., the point where the read data exceeds a predetermined level for each character or 25% of the maximum peak value of the previous character is detected as the start of the data. The address of the start of this data is set as the character start address (MHAD), and MHAD + 70 (hexadecimal) is set as the character end address (MEAD). and RBUF's MHAD
The data from to MEAD is taken as one character and its peak value is detected. However, as a noise countermeasure, data below a certain level are not subject to peak value detection. If the detected peak value is a plus peak value, enter this plus peak value and its address.
Set the detected peak value to the PTB, and set the detected peak value to the negative peak value and its address to the MTB.

FIG. 5 is a flowchart specifically showing the part of FIG. 3 in which the contents of PTB and MTB are rearranged in descending order of peak values. First, the contents of the first address of the PTB (the first plus peak value and its address) are set in the PPTB, and all the contents of the other addresses of the PTB are transferred to the peak data buffer (PDBF). Then, find the one with the largest peak value from the contents of PDBF, delete this maximum peak value and its address from PDBF, and set it in PPTB. By repeating this operation until PDBF is empty, 2nd peak value in PPTB is deleted. The peak value and the addresses are set in the order of the largest peak value for the address after the address.

Also, after all the contents of MTB are transferred to PDBF, they are similarly set in order of highest peak value.

FIG. 6 is a flowchart showing the part of FIG. 3 in which a character code is created. One character is divided into eight blocks and each block is read by sampling eight times, but the first half of the first block (four samplings) and the second half of the last block (four samplings) are always blank, so one character is essentially It is 7 blocks long. In addition, the read data is designed so that the peak of any character appears only once in one block, and each character always has two or three normal positive peaks and negative peaks. Furthermore, the magnetic ink characters are constructed so that the first plus peak of any character appears at the center of the first block. Therefore, first set the set data (SETD) to 80 (10000000 in binary) and set the plus code (PCODE) to 80.
Calculate the difference between the address PPTB(1) of the first plus peak value stored first and second in PPTB and the address PPTB(2) of the largest plus peak value among the other plus peak values. 4 from the difference
Subtract (half block) and divide by 8. The result of this calculation, Z, when rounded down to the decimal point, indicates how many blocks apart the first plus peak is from the largest plus peak among the other plus peaks. Therefore, if SETD is set to 40 and shifted to the right by Z, SETD becomes data that shows how many blocks away the largest positive peak among the other positive peaks is from the first positive peak, and OR with PCODE. Totsute 1st
Set the plus code in the code table. Address of the third plus peak value in PPTB
If PPTB(3) exists, similarly calculate the difference between PPTB(1) and PPTB(3), subtract 4 from the difference, divide by 8, and round off the decimal parts. and set SETD to 40 (2
01000000) and shift to the right by the calculation result Z, data indicating how many blocks apart the second largest positive peak among the other positive peaks is obtained from the first positive peak. This data is ORed with PCODE (first plus code) to become a second plus code and set in the code table. Since every letter has two or three regular plus peaks,
If there is no PPTB(3), set the first plus code in the code table and finish creating the plus code, and even if there is PPTB(4) or below, it is unnecessary, so set the second plus code. Set this in the code table to finish creating the plus code.

In addition, following the creation of the positive code, create the negative code in the same way based on PPTB (1), that is, create two or three negative peak values in descending order of negative peak value.
The addresses MPTB(1), MPTB(2),
Look at how far apart MPTB(3) and PPTB(1) are, create a negative code, and set it in the code table as shown in Figure 9.

FIG. 7 is a flowchart showing the portion of FIG. 3 in which peak duplication within the same block is detected, character code is re-created, and comparison is performed with a fixed code. By taking the logical product of the plus code and the minus code, it is detected whether a plus peak and a minus peak coexist in the same block. In this case, if two plus or minus codes were created, the last one was created (there are many "1"s)
The second plus code or second minus code fixes each character code consisting of each combination of plus code and minus code on the code table if two peaks do not coexist in the same block. It sequentially compares each fixed code on the code table, and if it matches any fixed code, the read character is determined to be a character of that fixed code and this code is set in the RAM 22. If there is no match, it is considered unrecognizable. Judge? the code of
Set to RAM22. If two peaks coexist in the same block, for example, if the minus code is "01000001" and the plus code is officially "10000010" but is actually "11000010", they will overlap. Recreate the plus code by ignoring the bit "1" for each plus code (in the above plus code, create it as "10000010"), and create the first type character code with this and the minus code. Set to code table. Furthermore, the minus code is recreated by ignoring the overlapping bit "1" for each minus code (in the above minus code, it is created as "00000001"), and the first created plus code (before re-creation). Create a second type character code and set it in the code table. Then, the first type character code and the second type character code are sequentially compared with each fixed code on the fixed code table, and if they match with any fixed code, this code is determined to be the code of the read character and is stored in the RAM 22. What if I set it and it doesn't match? The code of RAM2
Set to 2.

As described above, according to the present invention, when a plus peak and a minus peak overlap in the same block due to abnormal peaks, each one is ignored and two types of character codes are created to recognize the read characters. , the character recognition rate can be increased, and since the character code consists of a plus code and a minus code, it is possible to easily detect overlapping peaks in the same block.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the present invention, FIG. 2 is a block diagram showing an example of the apparatus used in the embodiment of the invention, FIGS. 3 to 7 are flowcharts showing the program of the same apparatus, and FIG. The figure shows the same device.
Figure 9 shows the RAM memory map.
FIG. 3 is a diagram showing a code table of RAM. 11...MPU, 22...RAM, 23...
ROM.

Claims (1)

[Claims] 1 Divide the magnetic variation data of magnetic ink characters into a predetermined number of blocks, detect which position of the blocks the peak position of the magnetic variation corresponds to, create a character code, and recognize the read character. In the magnetic ink character recognition method, a character code is created by creating a plus code and a minus code for each of the positive and negative peak positions among the above-mentioned peak positions. A magnetic ink character recognition method in which when two peaks overlap in the same block, each one of these peaks is excluded, two types of character codes are created, and the read characters are recognized.