JPH0668774B2 - Bar code reading method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barcode reading method, and more particularly to a method capable of reading a barcode of a special character which is out of a predetermined rule.

(Prior Art) There are various types of barcodes, and there are predetermined rules for each type.

As one of the typical ones of these barcode formats,
There is a code format called "NW-7". This code has 4 bars (black bars) and 3 spaces (white bars) for each character, as shown in the code table of FIG.
And usually only the numbers "0" to "9" are used as data. As is clear from the above code table, each of the numeric characters and "\" and "-" is wide in only one of the four bars and in only one of the three spaces. There is. Also, "a", which is mainly used as a start code and a stop code,
Special characters such as "b" ... are 1 out of 4 bars
Only one is wide, and two of the three spaces are wide. Furthermore, for special characters such as “.”, “+”, ..., 3 of the 4 bars are wide,
And all three spaces are narrow. And
A wide bar and a space mean a binary value "1", and a narrow bar and a space mean a binary value "0".

Various methods have been conventionally proposed as a method for reading the above bar code, but the present applicant has proposed the method to the utmost with respect to changes in the scanning speed of the reader and slight changes in the width of the bar and space. We have already applied for a barcode reading method that allows accurate reading.

The first method is Japanese Patent Application No. 59-221970 (Japanese Patent Laid-Open No. 61-101880).
The value corresponding to the width of each area consisting of the bar and the space is stored by scanning the bar code by the reader, and the comparison reference is based on the value corresponding to the width of each of the stored areas. This is a method of calculating a value, comparing the calculated comparison reference value with a value corresponding to the width of each of the areas, and determining the width of each of the areas according to the magnitude relationship.

The second method is disclosed in Japanese Patent Application No. 60-121570 (JP-A-62-9077).
6), the barcode is scanned by the reader to store the value corresponding to the width of each area consisting of the bar and the space, and the predetermined value among the values corresponding to the width of each of the stored areas is stored. Calculate the total value by adding up the values of the numbers, calculate the quotient of the calculated total value and the value corresponding to the width of each area, and compare this calculated value with the preset comparison value. Then, the width of each area is determined according to the magnitude relation.

The specific contents of the first and second reading methods will be described in detail in the embodiments of the present invention described later, but with respect to changes in the scanning speed of the reader, changes in the width of bars and spaces, and the like. Even though it has the advantage that accurate reading can be performed, the above-mentioned ".", "+" ...
・ There was a problem that special characters consisting of etc. could not be read. This is to calculate the comparison reference value or total value based on the value corresponding to the width of the bar and space for each character, and use the calculated comparison reference value or total value to determine the size of the area width of each bar and space. This is because the judgment method is adopted.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and basically, by adopting the first and second reading methods, a change in the scanning speed of the reader, a bar and a space are provided. It is an object of the present invention to provide a bar code reading method capable of coping with a slight change in width of the bar code and also capable of reading a special character.

(Outline of the Invention) In the present invention, a bar code is scanned by a reader to store a value corresponding to each area width consisting of a bar and a space, and a standard character is stored based on the stored value of each area width. Decoding is performed for each character in the decoding process, and a character having a decoding error in the standard character decoding process is decoded again in the special character decoding process.

(Embodiment) An embodiment of the barcode reading method according to the present invention will be described in detail below with reference to FIGS. 1 to 13.

FIG. 1 shows a circuit diagram of the reading device. The CPU 2 uses the bus line 1 to store the program storage circuit 3, the data storage circuit 4,
It is connected to the digital input / output circuit 5 and the display control circuit 6, respectively. The CPU 2 controls the entire operation according to the program of the program storage circuit 3 composed of ROM. In addition, the data storage circuit 4 configured by a RAM stores a region width storage unit M1, a storage unit M2 that stores a reference value or a total value, a read data storage unit M3, a temporary storage unit M4, and a storage that stores other data. It has a part M5.

A manual optical reader 7 for scanning a bar code is connected to the digital input / output circuit 5, and the digital input / output circuit 5 detects whether the reader 7 is scanning the area of the bar or the area of the space. It is configured to detect whether scanning is in progress and output the state to the bus line 1 as a binary signal. The display control circuit 6 is for displaying the contents on the display unit 8 such as a CRT display according to the display data converted based on the read data of the barcode stored in the read data storage unit M3. .

Next, a method of reading a bar code as shown in FIG. 12 with a reading device equipped with the above circuit will be described.
This bar code is of the type shown in the table of Fig. 13, and the ratio of the wide bar and the narrow bar to the bar and space is 3: 1.

First, a bar code reading method obtained by improving the first reading method described above will be described.

FIG. 2 shows the entire operation, and the counting operation is started first. This counting operation shows an operation in which the reader 7 scans the bar code shown in FIG. 12 to count and store a value corresponding to the width of each area consisting of a bar and a space. Details of this counting operation will be described with reference to FIG.

After each circuit shown in FIG. 1 is initially set,
The reader 7 determines whether or not the blank portion corresponding to the start margin indicated by L1 in FIG. 12 has been scanned. When the scanning of the preset start margin L1 is completed, it is judged whether or not the start margin L1 is completed, and when it is completed, it is judged in step 3-4 whether or not the reader 7 is scanning the bar. It If the start margin L1 is completed, the reader 7 is naturally in the process of scanning the bar, and the count value B of the bar set at the predetermined address of the storage unit M5 is incremented by one. While the reader 7 is scanning the first bar BA1, step 3-4
And 3-5 are repeated, and the value corresponding to the width of the first bar BA1 is counted. When the reader 7 finishes scanning the first bar BA1, the bar count value B stored in the storage unit M5 is stored in the area width storage unit M1.

Next, it is judged whether or not the reader 7 is scanning the space, and if the space is being scanned, the count value of the space is incremented by 1 and set in a predetermined address of the storage unit M5. Then, it is judged whether or not the count value of this space has reached the value of the width corresponding to the stop margin shown by L2 in FIG. 12, and if not, the operations of steps 3-7 to 3-9 are performed. Repeated first space SP
The value corresponding to the width of 1 is counted. When the reader 7 finishes scanning the first space SP1, the count value S of the space set in the memory M5 is stored in the area width memory M1 and then the process returns to step 3-4.

Similarly, in steps 3-4 to 3-6, the values corresponding to the widths of the second and subsequent bars BA2, BA3, BA4 ... Are counted and stored in the area width storage unit M1. From 3-7 to step 3-10, the values corresponding to the widths of the second and subsequent spaces SP2, SP3 ... Are counted and stored in the area width storage unit M1 respectively, so that the bar and space of the entire bar code are stored. A value corresponding to the area width of is counted. When the reader 7 counts the value corresponding to the area width of the stop margin L2 shown in FIG. 12, it is considered that the scanning of the bar code is completed, and the reference value calculation is started. The bar counts up by 1 in 2 steps 3-4, 3-5, and the space counts up by 1 in 3 steps 3-7, 3-8, 3-9. Conditions are different. For this reason,
It is preferable to equalize the bar and space counting conditions by adding a meaningless pseudo step after step 3-5.

By the above counting operation, the value corresponding to the width of the area formed by each bar and space of the entire bar code shown in FIG. 12 is stored in the area width storage unit M1. Next, the reference value calculation of the standard character shown in step 2-2 in FIG. 2 is started. Details of the reference value calculation operation will be described with reference to FIG.

First, in step 4-1, the digit number A of the character of the entire bar code is obtained. The number of digits A of this character represents how many characters the entire barcode is composed of.
(The number of digits A = 5 in the example of FIG. 12) is set in a predetermined address of the storage unit M5.

Then, the count values of the four bars corresponding to the first character are summed up, and the summed value is stored in the program storage circuit 3
The comparison reference value corresponding to the bar of the first character by dividing by the preset constant K1 stored in
It is stored in the storage unit M2 as N1. Next, the count values of the three spaces for the first character are summed, and this total value is divided by a preset constant K2 stored in the program storage circuit 3 to obtain the space for the first character. The comparison reference value N2 is stored in the storage unit M2. The above-mentioned constant K1 is set to 3 so that the comparison reference value N1 is approximately the intermediate value between the count value corresponding to the narrow bar and the count value corresponding to the wide bar, and the comparison reference value N2 is set to the narrow space. The constant K2 is set to 2.5 so as to be an approximately intermediate value between the count value corresponding to and the count value corresponding to the wide space.

This completes the calculation of the reference values N1 and N2 corresponding to the bars and spaces for the first character, and the number of characters A
Is subtracted by 1. Then, it is judged whether or not the number of digits A becomes 0, and if it is not 0, step 4-
The steps 3 to 4 are repeated, and the reference values of the bar and space in charge of the subsequent characters are calculated and stored in the storage unit M2. When it is determined that the number of digits A is 0, it is considered that the calculation of the reference value corresponding to the bar and the space of the entire bar code is completed. When the reference value calculation is completed, step 2-3 in FIG.
Move on to the data comparison of the standard character shown by. Next, details of this data comparison operation will be described with reference to FIG.

First, in step 5-1, the digit number A of the character is set again, and further, the address of the storage unit M2 in which the reference values N1 and N2 of the first character are stored is set in the storage unit M5. When this setting is completed, the total number of bars and spaces for one character D = 8 is set in a predetermined address of the storage unit M5 in step 5-3. Note that the total number of bars and spaces is actually 7 as shown in FIG. 12, but since the intercharacter space CS is added to this, the total number D is set to 8.

Then, in step 5-4, it is determined whether the first count value stored in the area width storage unit M1 is a bar or a space. In the case of a bar, the address of the comparison reference value of the first character set in the storage unit M5 is referred to and the comparison reference value N1 of the bar of the first character stored in the storage unit M2 is set in the register D in the CPU2.・ Set in Ereg. Next, in step 5-6, the count value of the first bar BA1 stored in the area width storage unit M1 and step 5
In -5, the size is compared with the comparison reference value N1 of the bar of the first character set in the register D / Ereg,
If the count value is larger than the comparison reference value N1, the first bar is judged to be a binary value "1", and if the count value is not larger than the comparison reference value N1, it is judged to be a binary value "0". The data of these binary values "1" or "0" is stored in the temporary storage unit M4. In the example of FIG. 12, the first bar BA1 is narrow, and its count value is smaller than the comparison reference value N1. Therefore, the binary value “0” is stored.

Then, after D is decremented by 1, it is judged in step 5-9 whether or not D = 0, and if it is not 0, the process returns to step 5-4. Therefore, since the count value of the first space SP1 is stored in the second of the area width storage unit M1, refer to the address of the comparison reference value N2 corresponding to the space of the first character set in the storage unit M5. And storage
CP of the comparison reference value N2 for the space of the first character from M2
Set to register D • Ereg in U2. Then, the second data stored in the area width storage unit M1, that is, the count value corresponding to the width of the first space SP1 and the register DE
The comparison reference value N2 of the space set in reg is compared with the size relationship. As a result of this comparison, if the count value of the space SP1 is larger than the comparison reference value N2, it is judged as a binary value "1", and if it is not larger, it is judged as a binary value "0". As a result, the binary value "1" or "0" is stored in the temporary storage unit M4. In the twelfth example, the first space SP1 is narrow and the count value is not larger than the comparison reference value N2, so that the binary value “0” is stored. Then, after the value of D is decremented by 1, the process proceeds to step 5-9. By repeating this operation, the data of the bar and space for the first character and the space between characters are compared.

When it is determined that D = 0 in step 5-9,
1 stored in the temporary storage unit M4 in step 5-12
The first 7 bits of the character data, that is, the content corresponding to the bar and space data excluding the inter-character space CS is stored in the read data storage unit M3. Then, in step 5-13, the address data of the comparison reference value of the first character set in the memory M5 is cleared to set the address data of the comparison reference value of the next character, and in step 5-14. The number of digits of the character A
Is subtracted by 1. Next, in step 5-15, it is judged whether or not the number of digits A is 0. If it is not 0, steps 5-3 to 5-15 are repeated to successively compare the data of bars and spaces for each character. Do. Further, the data obtained as a result of this comparison is stored in the read data storage unit M3 in a predetermined order. The space between the characters is the final character.
Since there is no CS and the total number of bars and spaces is 7, the 8th binary value determined in step 5-6 is completely meaningless. The second binary value is discarded, so there is no problem.

When the data comparison of the bars and spaces for all the characters and the data storage of the comparison results are completed in this way, the digit number A of the character becomes 0, and the process proceeds to step 2-4 in FIG.

In this step 2-4, 7-bit data corresponding to the first character stored in the read data storage unit M3 is set in the register Areg in the CPU2. Then, in step 2-5, the 7-bit code “0011000” corresponding to “¥” shown in FIG. 13 is called from the program memory circuit 3 and the register Br in the CPU 2 is
Set to eg.

Next, in step 2-6, the contents of Areg and Breg are compared, that is, it is judged whether or not the first character is "¥". Actually, the data set in the register Areg has the content equivalent to "1", so Ar
When it is judged that eg = Breg is not established, the process proceeds to step 2-7,
A determination is made whether the comparison with all the codes shown in Figure 13 is complete. When the comparison with all the codes is not completed, the code corresponding to the next "-" is set in Breg and then the comparison of Areg = Breg is performed again. By repeating such operation, Breg displays "000001".
With 1 "set, the condition of Areg = Breg is satisfied, and in step 2-9, the character" 1 "corresponding to the code set in Breg is set at a predetermined address of the memory M5.

Next, after clearing the flag set in the predetermined address of the storage unit M5, it is judged in step 2-11 whether or not the decoding of all the characters is completed. If not, the read data is stored. The 7-bit data corresponding to the second character stored in the section M3 is set in the register Areg. This second character is also judged in the same way as the above-mentioned first character,
The character "2" is set at a predetermined address in the storage unit M5.

Next, 7-bit data corresponding to the third character is set in the register Areg and compared with the code under "\" which is sequentially set in the register Breg.
However, the third "/" is a special character in which three of the four bars are wide and the three spaces are all narrow, which is different from the standard character such as numbers. Therefore, since the accurate reference value is not calculated in the reference value calculation of the standard character shown in FIG. 4, the 7-bit data corresponding to the third “/” is “1010001” as shown in FIG. It will not be "0000000".

If the data is "0000000" like this,
Even if the steps 2-6 to 2-8 in FIG. 2 are repeated and the comparison operation with all the codes is completed, the contents of Areg and Breg do not match, and it is determined that there is a decoding error. If a decoding error occurs, it is determined in step 2-13 whether or not the special character is decoded by checking whether the flag in the storage unit M5 is "1". If it is determined that it has not been performed, step 2
Start the calculation of the reference value for the -14 special character. next,
The calculation of the reference value for this special character will be described with reference to FIG.

First, in step 6-1, the count values of the four bars corresponding to the character currently being decoded are summed. And
By dividing this total value by a preset constant K3 stored in the program storage circuit 3, a comparison reference value N3 corresponding to the bar of the character currently being decoded is calculated and stored in the storage unit M2. Next, the count values of the three spaces are summed, and this total value is divided by a preset constant K4 stored in the program memory circuit 3 to store it as a space comparison reference value N4 in the memory unit M2. . The above-mentioned constant K3 is set to 5 so that the above-mentioned comparison reference value N3 is an approximately intermediate value between the count value corresponding to the narrow bar of “.” To “/” and the count value corresponding to the wide bar, and The above-mentioned constant K4 is set so that the comparison reference value N4 is an intermediate value between the count value corresponding to the narrow space and the count value corresponding to the wide space.
It is set to 1.5.

When the calculation of the reference value of the special character is completed in this way, the data comparison of the special character as shown in FIG. 7 is performed.

In this data comparison, first, in step 7-1, the total number of bars and spaces for one character D =
8 is set in a predetermined address of the storage unit M5. Then, in step 7-2, it is determined whether the first count value of the character currently being decoded, which is stored in the area width storage unit M1, is a bar or a space. If it is a bar, the bar comparison reference value N3 stored in the storage unit M2 is set to CP.
Set in register D / Ereg in U2. Next, in step 7-4, the count value of the first bar of the character currently being decoded stored in the area width storage unit M1 and the bar comparison reference value set in the register D • Ereg in step 7-3. If the count value is greater than N3 and the count value is larger than the comparison reference value N3, the first bar is judged to be a binary value "1", and if the count value is not larger than the comparison reference value N3, a binary value "0". Is judged. The data of these binary values "1" or "0" is stored in the temporary storage unit M4. Then, after D is decremented by 1, in step 7-7 D
After it is judged whether or not = 0, if it is not 0, the process returns to step 7-2.

Next, in step 7-2, it is determined that the second count value is a space, and the comparison reference value N4
Is set in a predetermined register D / Ereg in the CPU2. Then, the magnitude relationship between the second count value stored in the area width storage unit M1, that is, the count value corresponding to the width of the first space and the comparison reference value N4 of the space set in the register D • Ereg is calculated. Compare. As a result of this comparison, if the count value of the space is larger than the comparison reference value N4, it is judged to be a binary value "1", and if it is not larger, it is judged to be a binary value "0". As a result, the binary value "1" or "0" is stored in the temporary storage unit M4. Then, after the value of D is decremented by 1, the process proceeds to step 7-7. By repeating this operation, data comparison between the bar and space for the character currently being decoded and the space between characters is performed. When it is determined that D = 0 in step 7-7, it is considered that the data comparison is completed, and the process proceeds to step 2-16 shown in FIG.

In step 2-16, the first 7 bits of the special character data stored in the temporary storage unit M4,
That is, the contents corresponding to the bar and space data excluding the inter-character space CS are registered in the register Areg
set. Then, set the flag to "1", and
After setting the first code in Breg, step 2-6 ~
By repeating step 2-8, it is recognized that the character currently being decoded, that is, the third character shown in FIG. 12 is "/", and the content thereof is set to M5 in step 2-9.

When the above setting is completed, the flag is cleared and the next character data, that is, the fourth character data is set in Areg. The fourth and fifth character data are decoded in the same manner as the first and second character data. When the decoding of all the five characters shown in FIG. 12 is completed in this way, it is judged in step 2-11 that all the characters have ended, and the decoded contents "12/23" are shown in FIG. The image is displayed on the display unit 8 via the display control circuit 6.

If the character cannot be recognized even if the special character is decoded, that is, if the flag is "1" even though the comparison of all the codes is completed, it is judged as a reading error in the display unit 8 in step 2-19. After the error is displayed and the flag is cleared, the process returns to step 2-1.

As described above, the standard characters such as "\", "-", and "numerals" and the special characters including "." To "/" can be accurately read.

It should be noted that "a" to "e" can be read in the process of decoding the standard character, since there is only one wider space than the standard character.
It is also possible to calculate and decode the comparison reference value using the most suitable special constant in the same manner as "." To "/" described above. In particular, since these "a" to "e" are generally used as the start code and the end code, only the first and last characters are compulsorily calculated by using the above special constant to calculate the comparison reference value. It is also possible to do so.

Next, a barcode reading method obtained by improving the above-mentioned second reading method will be described.

In step 8-1 of FIG. 8, a value corresponding to the area width of each bar and space of the bar code is counted. This counting operation is the same as that of the above-described embodiment described with reference to FIG.

By the above counting operation, a value corresponding to the width is stored in the area width storage unit M1 in the area formed by each bar and space of the entire barcode as shown in FIG. When the counting operation is completed, the standard character total value calculation shown in step 8-2 in FIG. 8 is started.

This total value calculation will be explained with reference to FIG.
First, in step 9-1, the digit number A of the character of the entire bar code is obtained. The number of digits A of this character represents how many characters the entire bar code is composed of, and the obtained number of digits A is set in a predetermined address of the storage unit M5.

Then, the count values of the four bars corresponding to the first one character are totaled, and the total value P1 is stored in the storage unit M2. Next, the count values of the three spaces for the first character are summed, and this sum value P2 is stored in the storage unit M2.

This completes the calculation of the total values P1 and P2 corresponding to the bar and space for the first character, and the number of digits of the character A
Is subtracted by 1. Then, it is judged whether or not the digit number A becomes 0, and if it is not 0, step 9-
Steps 3 to 3 are repeated from 3 to calculate the total value of the bar and space corresponding to the subsequent characters and store them in the storage unit M2. If it is determined that the number of digits A is 0, it is considered that the calculation of the total value corresponding to the bar and space of the entire bar code has been completed, and the data comparison of the standard character shown in step 8-3 is performed. Move.

Next, with reference to FIG. 10, an operation of performing data comparison of each bar and space using the total values P1 and P2 calculated as described above will be described.

First, in step 10-1, the digit number A of the character is set again, and further, the address of the storage unit M2 in which the total values P1 and P2 of the first character are stored is set in the storage unit M5. When this setting is completed, the total number of bars and spaces for one character D = 8 including the inter-character space CS is set to a predetermined address of the storage unit M5 in step 10-3.

Then, in step 10-4, it is determined whether the first total value stored in the storage unit M2 is a bar or a space. In the case of a bar, the bar total value of the first character stored in the storage unit M2 is referred to by referring to the address of the total value of the first character set in the storage unit M5.
P1 is set in the register D.Ereg in the CPU2, and in step 10-6, the bar comparison value Q1 previously stored in the program storage circuit 3 is set in the register H.
Set to Lreg.

When the setting of the comparison value Q1 is completed, the quotient is calculated by dividing the total value P1 of the bar of the first character by the count value of the first bar BA1 in step 10-7, and the calculated value and the comparison value of the bar. Comparison with Q1 is made. As a result of the comparison, if the calculated value is larger than the comparison value Q1, the first bar is judged as a binary value "0", and if the calculated value is not larger than the comparison value Q1, it is judged as a binary value "1". . These binary values "1"
Alternatively, the data “0” is stored in the temporary storage unit M4. In the example of FIG. 12, the first bar BA1 is narrow and the calculated value is larger than the comparison value Q1. Therefore, the binary value “0” is stored.

Then, after D is decremented by 1, it is judged in step 10-10 whether or not D = 0, and if it is not 0, the process returns to step 10-4. Therefore, since the count value of the first space SP1 is stored in the second of the area width storage unit M1, the total value P2 of the space for the first character from the storage unit M2 is set in the register D • Ereg, and Step 10-
At 12, the comparison value Q2 of the space previously stored in the program storage circuit 3 is set in the register H • Lreg.

When these sets are completed, in step 10-7, the total value P2 of the spaces of the first character is changed to the first space.
The quotient is calculated by dividing by the count value of SP1, and the calculated value and the comparison value Q2 are compared in magnitude. As a result of this comparison,
When the calculated value is larger than the comparison value Q2, it is determined to be a binary value "0", and when it is not larger, it is determined to be a binary value "1". As a result, the binary value "1" or "0" is stored in the temporary storage unit M4. In the example of FIG. 12, the first space SP1 is narrow and the calculated value is larger than the comparison value Q2, so the binary value “0” is stored. Then, after the value of D is decremented by 1, the process proceeds to step 10-10. By repeating this operation, the data of the bar and space for the first character and the space between characters are compared.

The comparison value Q1 is set to an approximately intermediate value between the total bar value divided by the narrow bar count value and the wide bar count value, and the comparison value Q2 is the total space value. It is set to an approximately intermediate value between the value divided by the count value of the narrow space and the value divided by the count value of the wide space.

After the data comparison of the bar and space for one character is completed and it is determined that D = 0 in step 10-10, the first of the data for one character stored in the temporary storage unit M4 in step 10-14. 7 bits, that is, the contents corresponding to the bar and space data excluding the inter-character space CS are stored in the read data storage unit M3. Then, in step 10-15, the address data of the total value of the first character set in the storage unit M5 is cleared and the address data of the total value of the next character is set,
At the step 10-16, the digit number A of the character is decremented by 1. Next, at step 10-17, the number of digits A is 0.
If it is not 0, it is determined whether or not step 10
-3 to steps 10-17 are repeated to sequentially compare data of bars and spaces for each character. Also, the data obtained as a result of this comparison is
The read data is stored in the read data storage unit M3 in a predetermined order. Since the final character has no inter-character space CS and the total number D of bars and spaces is 7, the eighth binary value determined in step 10-7 has no meaning. , The eighth binary value is discarded in steps 10-14, so no problem occurs.

When the data comparison of the bars and spaces for all the characters and the data storage of the comparison results are completed in this way, the digit number A of the character becomes 0, and the process proceeds to step 8-4 in FIG.

In this step 8-4, 7-bit data corresponding to the first character stored in the read data storage section M3 is set in the register Areg in the CPU2. Then, in step 8-5, the 7-bit code “0011000” corresponding to “¥” shown in FIG. 13 is called from the program memory circuit 3 and the register Br in the CPU 2 is updated.
Set to eg.

Next, at step 8-6, the contents of Areg and Breg are compared, that is, it is judged whether or not the first character is “¥”. Actually, the data set in the register Areg has the content equivalent to "1", so Ar
When it is judged that eg = Breg is not established, the process proceeds to step 8-7,
A determination is made whether the comparison with all the codes shown in Figure 13 is complete. When the comparison with all the codes is not completed, the code corresponding to the next "-" is set in Breg, and then the comparison of Areg = Breg is performed. By repeating such an operation, the condition of Areg = Breg is satisfied while "0000011" is set in Breg, and the character "1" corresponding to the code set in Breg is set in step 8-9. It is set at a predetermined address in the storage unit M5.

Next, after clearing the flag in the storage unit M5, step 8
At -11, it is determined whether all the characters have been decoded. If not, the 7-bit data corresponding to the third character stored in the read data storage unit M3 is stored in the register Areg. Is set to.
The second character is also determined in the same manner as the first character described above, and the character "2" is set at the predetermined address of the storage unit M5.

Next, 7-bit data corresponding to the third character is set in the register Areg and compared with the code sequentially set in the register Breg. However, the third "/" is a special character in which three of the four bars are wide and the three spaces are all narrow, which is different from the standard character such as numbers. Therefore, since accurate data is not created in the data comparison of the standard characters shown in FIG. 10, the 7-bit data corresponding to the third "/" is not "1010001" as shown in FIG. Without "1111011"
It will be wrong such as.

When the data is "1111011" like this,
Even if the steps 8-6 to 8-8 in FIG. 8 are repeated and the comparison operation with all the codes is completed, the contents of Areg and Breg do not match and it is judged that there is a decoding error. If a decoding error occurs, it is determined in step 8-13 whether or not the special character is decoded by checking whether the flag in the storage unit M5 is "1".
If it is determined that the operation has not been performed, step 8-14
The data comparison of the special character of is started.

Next, the data comparison of this special character will be described with reference to FIG.

First, in step 11-1, the total number of bars and spaces for one character D = 8 is set in a predetermined address of the storage unit M5. Then, in step 11-2, the area width storage unit M1
It is determined whether the first count value of the character currently being decoded stored in is a bar or a space. If it is a bar, the total value P1 of the bar of the character currently being decoded, which is stored in the storage unit M2, is set in the register D.Ereg, and stored in the program storage circuit 3 in advance in step 11-4. The comparative value Q3 of the bar for the special character present is set in the registers H and Lreg.

When these sets are completed, in step 11-5, the quotient is calculated by dividing the bar total value P1 of the character currently being decoded by the count value of the first bar, and the calculated value and the bar comparison value Q3. It is compared with the size. As a result of the comparison,
When the calculated value is larger than the comparison value Q3, the first bar is determined to be a binary value "0", and when the calculated value is not larger than the comparison value Q3, it is determined to be a binary value "1". The data of these binary values "1" or "0" is stored in the temporary storage unit M4. In the example of FIG. 12, the first bar is wide and the calculated value is not larger than the comparison value Q3, so the binary value “1” is stored.

Then, after D is decremented by 1, it is judged in step 11-8 whether D = 0, and if it is not 0, the process returns to step 11-2. Therefore, when it is determined that the second count value is a space, the total value P2 of the spaces of the characters currently being decoded from the storage unit M2 is stored in the register D · Er.
Then, in step 11-10, the comparison value Q4 of the special character space previously stored in the program storage circuit 3 is set in the register H.Lreg.

Then, in step 11-5, the quotient is calculated by dividing the total value P2 of the spaces by the count value of the first space currently being decoded, and the calculated value and the comparison value Q4 are compared in magnitude. As a result of this comparison, if the calculated value is larger than the comparison value Q4, it is judged to be a binary value "0", and if it is not larger, it is judged to be a binary value "1". As a result, the binary value "1" or "0" is stored in the temporary storage unit M4. In the example of Fig. 12, the first space is narrow, and its calculated value is the comparison value Q4.
Since it is larger, the binary value "0" is stored. And
After the value of D is decremented by 1, the process proceeds to step 11-8. By repeating this operation, the data of the bar and space for the first character and the space between characters are compared.

The comparison value Q3 is set to an approximately intermediate value between the total number of bars in the special character divided by the count value of the narrow bar and the value divided by the count value of the wide bar, and the comparison value Q4 is set as the special character. It is set to an approximately intermediate value between a value obtained by dividing the total value of the spaces in the above by the count value of the narrow space and a value obtained by dividing it by the count value of the wide space.

If it is determined that D = 0 in step 11-8 as described above, it is considered that the data comparison is completed, and
Move to steps 8-15 shown in the figure.

In step 8-15, the contents corresponding to the first 7 bits of the data for the special characters stored in the temporary storage unit M4, that is, the bar and space data excluding the inter-character space CS are stored in the CPU2. register
Set to Areg. Then, after the flag is set to "1" and the first code is set to Breg, step 8-
By repeating steps 6 to 8-8, it is recognized that the character currently being decoded, that is, the third character shown in FIG. 12 is "/", and its content is set to M5 in step 8-9. .

When the above setting is completed, the flag is cleared and the next character data, that is, the fourth character data is set in Areg. The fourth and fifth character data are decoded in the same manner as the first and second character data. When the decoding of all the five characters shown in FIG. 12 is completed in this way, it is judged in step 8-11 that all the characters have ended, and the decoded contents "12/23" are shown in FIG. The image is displayed on the display unit 8 via the display control circuit 6.

If the character cannot be recognized even if the special character is decoded, that is, if the flag is "1" even though the comparison of all codes is completed, it is determined as a reading error in the display unit 8 in step 8-18. After the error is displayed on the screen and the flag is cleared, the process returns to step 8-1.

As described above, the standard characters such as "\", "-", and "numerals" and the special characters including "." To "/" can be accurately read. Also, for “a” to “e”, the most suitable comparison value is prepared similarly to the above “.” To “/”, and in a special character decoding process different from “.” To “/”. Can be decoded.

In the above embodiment, only the reading of the code called "NW-7" was explained, but the code called "code 39" in which each character consists of 5 bars and 4 spaces. Etc. can be applied. In this "code 39", the standard character has two wide bars and one wide space set, but the special character has no wide bar and has three wide spaces.

(Effect) As described above, in the present invention, the bar code is operated by the reader to store the value corresponding to each area consisting of the bar and the space, and the standard value is stored based on the value of each area width stored. Decoding is performed for each character in the character decoding process, and a character having a decoding error in the standard character decoding process is decoded again in the special character decoding process. Therefore, not only the standard character but also the special character can be surely read, and there is no need to make a complicated judgment in advance as to whether the character to be decoded is the standard character or the special character. Further, the standard character and the special character can be distinguished regardless of the number of characters.

[Brief description of drawings]

Each drawing shows an embodiment of the present invention, FIG. 1 is a block diagram showing a circuit diagram of a reading device, FIGS. 2 to 7 show a first embodiment, and FIG. FIG. 3 is a flow chart showing the entire operation, FIG. 3 is a flow chart showing the counting operation, FIG. 4 is a flow chart showing the reference value calculation operation of the standard character, and FIG. 5 is a flow chart showing the data comparison operation of the standard character. 6 is a flow chart showing the reference value calculation operation of the special character, FIG. 7 is a flow chart showing the data comparison operation of the special character, and FIGS. 8 to 11 show the second embodiment.
FIG. 9 is a flowchart showing the whole reading operation, FIG. 9 is a flowchart showing the total value calculation operation of standard characters, FIG. 10 is a flowchart showing the data comparison operation of standard characters, and FIG. 11 is the data comparison of special characters. FIG. 12 is a flowchart showing the operation, FIG. 12 is a diagram showing an example of the barcode, and FIG. 13 is a code table of the barcode shown in FIG. In the drawing, 2 ... CPU, 3 ... Program storage circuit 4 ... Data storage circuit, 6 ... Reader 8 ... Display unit

Claims (1)

[Claims] 1. At least one of a bar and a space arranged alternately has a width of two or more kinds, and a bit value is expressed by the size of the width, and a standard character and the same code format as the standard character. However, in a bar code reading method for reading a bar code configured to represent a special character having a wide bar and a narrow bar, and a number ratio for a wide space and a narrow space different from that of the standard character, By scanning the bar code, all the values corresponding to the width of each area consisting of the bar and the space are stored, and based on the stored value of each area width, the comparison reference according to the configuration of the standard character. Decodes each character in the standard character decoding process using values,
By comparing this decoded code with the stored code, error judgment is made for all characters. For characters that have a decoding error in this standard character decoding process, comparison is made according to the structure of the special character. A bar code reading method characterized in that it is decoded again in a special character decoding process using a reference value, and a reading error is finally judged in the special character decoding process.