JPS6249579A - Bar code reading method - Google Patents

Abstract

PURPOSE:To read special characters by decoding again characters having a decoding error in a decoding process of standard characters in a decoding process of special characters. CONSTITUTION:Bar codes are operated by a reader 7 to store values corresponding to respective areas consisting of bars and spaces in a data storing circuit 4. Then respective characters are decoded in a standard character decoding process according to the value stored in each area. The character having a decoding error in the standard character decoding process is decoded again in the special character decoding process. In such a way, not only the standard character but also the special characters can also be read completely. This omits a process to decide whether the characters to be decoded are equal to standard or special characters.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a barcode reading method, and more particularly to a method capable of reading barcodes with special characters that deviate from predetermined rules.

(Prior Art) There are various types of barcodes, and each type has its own predetermined rules.

One of the typical barcode formats is
There is a code format called rNW-7J. As shown in the code table in Figure 13, this code consists of four bars (black bars) and three spaces (white bars) for each character, and is usually a number between "0" and "9". only used as data. As is clear from the code table above, each numeric character, "\" and "-" have only one wide bar out of four bars and one wide out of three spaces. There is. Also, raJ is mainly used as a start code and stop code.
, rbJ, etc., only one of the four bars is wide.

And two of the three spaces are wide. Furthermore, special characters such as r, ", r+", etc.
Three of the bars are wide, and all three spaces are narrow. Both the bar and the space are defined so that a wide one means a binary value rlJ, and a narrow one means a binary value "0".

Various methods have been proposed in the past for reading barcodes such as those mentioned above, but the applicant has developed a method that takes into account changes in the scanning speed of the reader, slight changes in the width of bars and spaces, etc. An application has already been filed for a barcode reading method that allows accurate reading.

The first method, filed as Japanese Patent Application No. 59-221970, stores a value corresponding to the width of each area consisting of bars and spaces by scanning a bar code with a reader, and each of the stored values is A comparison reference value is calculated based on the value equivalent to the width of the area, and the calculated comparison reference value is compared with the value equivalent to the width of each of the above areas, and the width of each of the above areas is determined according to the size relationship. This is the way to do it.

The second method, which has been filed as Japanese Patent Application No. 121570/1982, stores a value corresponding to the width of each area consisting of bars and spaces by scanning a barcode with a reader. A total value is calculated by summing a predetermined number of values corresponding to the width of each area, and the quotient of this calculated total value and the value corresponding to the width of each area above is calculated to obtain this calculated value. In this method, the width of each area is determined based on the magnitude relationship between the two and a preset comparison value.

The specific contents of the first and second reading methods will be explained in detail in the embodiments of the present invention to be described later, but it is possible to Although it has the advantage of being able to perform accurate readings even when using
There remained the problem that special characters such as ・ etc. could not be read. This calculates a comparison reference value or total value for each character based on the value equivalent to the width of the bar and space, and then uses the calculated comparison reference value or total value to calculate the width of the area made up of each bar and space. This is because a method of judgment is adopted.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and basically, by adopting the reading method described in Section 1-1, the scanning speed of the reader can be changed, the bar and To provide a barcode reading method that can cope with slight changes in the width of a space and can also read special characters.

(Summary of the Invention) In the present invention, by scanning a barcode with a reader, values corresponding to the widths of each region consisting of bars and spaces are stored, and based on the stored values of the widths of each region, standard characters are Each character is decoded in the decoding process, and any character that results in a decoding error in the standard character decoding process is decoded again in the special character decoding process.

(Example) Hereinafter, an example of the barcode reading method according to the present invention will be described in detail with reference to FIGS. 1 to 13.

FIG. 1 shows a circuit diagram of a reading device, in which a CPU 2 is connected to a program storage circuit 3, a data storage circuit 4, . Digital input/output circuit 5° and display control circuit 6
are connected to each other. This CPU 2 is designed to control the overall operation according to a program stored in a program storage circuit 3 constituted by a ROM. Also, R.A.
The data storage circuit 4 includes an area width storage section Ml, a storage section M2 .
Read data storage section M3. It has a temporary storage section M4° and a storage section M5 for storing other data.

A manual optical reader 7 for scanning barcodes is connected to the digital input/output circuit 5, and the digital input/output circuit 5 detects whether the reader 7 is scanning a bar area or a space area. The 0 display control circuit 6, which is configured to detect whether scanning is in progress and output the status as a binary signal to the pass line l, reads the barcode stored in the read data storage section M3. This is for displaying the contents on a display unit 8 made of a CRT display or the like according to display data converted based on the data.

Next, a method of reading a bar code as shown in FIG. 12 using a reading device equipped with the above circuit will be described. It is assumed that this barcode is of the format shown in the table of FIG. 13, and that the ratio of wide to narrow bars and spaces is 3:1.

First, a barcode reading method that is an improved version of the first reading method described above will be described.

FIG. 2 shows the overall operation, and first a counting operation is started. This counting operation shows an operation in which the reader 7 scans the bar code shown in FIG. 12, thereby counting and storing values corresponding to the width of each area consisting of bars and spaces. The details of this counting operation will be explained with reference to FIG.

After each circuit shown in Figure 1 has been initialized,
It is determined by the reader 7 whether a blank area corresponding to the start margin indicated by Ll in FIG. 12 has been scanned. Preset start margin L1
When the scanning of the bar is completed, it is determined whether the start margin Ll has ended or not, and when it is completed, it is determined in step 3-4 whether the reader 7 is scanning the bar or not. If the start margin Ll has ended, the reader 7 is naturally scanning the bar, and adds 1 to the bar count value B set at a predetermined location in the storage section M5. Steps 3-4 and 3-5 are repeated while the reader 7 is scanning the first bar BAI, and the value corresponding to the width of this first bar BAI is counted. When the reader 7 finishes scanning the first bar BAI, the bar count value B stored in the storage section M5 is stored in the area width storage section M1.

Next, it is determined whether the reader 7 is scanning a space or not, and if it is scanning a space, the count value of the space is incremented by 1 and set in a predetermined location in the storage section M5. And the count value of this space is shown in Figure 12.
It is determined whether the width value corresponding to the stop margin shown in 2 has been reached, and if it has not been reached, step 3-
The operations from step 7 to step 3-9 are repeated and a value corresponding to the width of the first space SPI is counted. When the reader 7 finishes scanning the first space SPI, the memory M5
After storing the space count value S set in the area width storage unit Ml, the process returns to step 3-4.

Thereafter, in the same manner, from step 3-4 to step 3-6, the second and subsequent bars BA2, BA3, BA4, etc.
A value corresponding to the width of .
The second and subsequent spaces SP2, 5P3-...
The values corresponding to the width of the bar code are counted and stored in the area width storage section M1, thereby counting the value corresponding to the width of the area consisting of bars and spaces of the entire barcode.

When the reader 7 counts a value corresponding to the area width of the start margin L2 shown in FIG. 12, it is assumed that scanning of the bar code is completed, and the process moves on to the reference value calculation. In addition,
For the bar, count by l using the two steps of 3-4.3-5.

As for the space, it is counted up by 1 in the three steps of 3-7.3-8.3-9, and the counting conditions for both are different. Therefore, it is preferable to equalize the counting conditions for bars and spaces by adding a meaningless pseudo step after step 3-5.

By the above counting operation, a value corresponding to the width of the area consisting of each bar and space of the entire barcode shown in FIG. 12 is stored in the area width storage unit Ml. The standard value calculation for the standard character shown in step 2-2 begins. For details of this standard value calculation operation, see Section 4.
This will be explained with reference to the figures.

First, in step 4-1, the number of character digits A of the entire barcode is determined. The number of digits A of this character represents how many characters the entire barcode is made up of, and the number of digits A obtained is
(In the example of FIG. 12, the number of digits A=5) is set at a predetermined location in the storage section M5.

Then, the count values of the four bars corresponding to the first character are totaled, and this total value is stored in the program storage circuit 3.
By dividing by a preset constant Kl stored in , the count value of three spaces for the first character is stored in the storage unit M2 as a comparison reference value Nl corresponding to the bar of the first character. The total value is divided by 2 to a preset constant stored in the program storage circuit 3 to obtain a comparison reference value N2 of the space corresponding to the first character in the memory unit M.
Store in 2. The constant Kl is set to 3 so that the comparison reference value N1 is approximately the middle 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 3 for the count value corresponding to the narrow bar and the count value corresponding to the wide bar. The constant 2 is set to 2.5 so that the count value corresponding to the wide space is approximately the middle value between the count value corresponding to the wide space and the count value corresponding to the wide space.

This completes the calculation of the reference values Nl and N2 corresponding to the bar and space for the first character, and the number of digits A of the character is subtracted by one. Then, it is determined whether this number of digits A has become O, and if it is not O, steps 4-3 to 4-10 are repeated to calculate the standard values of bars and spaces corresponding to subsequent characters. and are respectively stored in the storage unit M2. Also, one digit number A
If it is determined that is O, it is considered that the reference value calculation corresponding to the bars and spaces of the entire barcode has been completed. When the reference value calculation is completed, the process moves on to the data comparison of the standard character shown in step 2-3 in FIG. 2. Next, the details of this data comparison operation will be explained with reference to FIG. 5.

First, in step 5-1, the number of digits A of the character is set again, and the reference values Nl and N of the first character are set again.
The address of the memory section M2 where 2 is stored is set in the memory section M5. When this set is completed, in step 5-3 the total number of bars and spaces D for l characters is
=8 is set at a predetermined location in the storage section M5. The total number of bars and spaces is actually 7 as shown in FIG. 12, but since the inter-character space C5 is added to this, the total number is set to 8.

Then, in step 5-4, it is determined whether the first count value stored in the area width storage section M1 is a bar or a space. If it is a bar, refer to the address of the comparison reference value of the first character set in the storage unit M5 and set the comparison reference value Nl of the bar of the first character stored in the storage unit M2 to the register D in CPUZ. m
0 set in E reg Next, in step 5-6, the count value of the first bar BA1 stored in the area width storage unit M1 and the register D in step 5-5 are set.
++ The bar of the first character set in E reg is compared in size with the comparison reference value Nl, and if the count value is greater than the comparison reference value N1, the first bar is a binary value "
If the count value is not larger than the comparison reference value Nl, it is determined to be a binary value of "0". These binary values “
Data of "1" or "0" is stored in the temporary storage section M4. In the example of FIG. 12, the first bar BAI is narrow and its count value is smaller than the comparison reference value Nl, so a binary value "0" is stored.

After D is subtracted by l, it is determined in step 5-9 whether D=0, and if it is not O, the process returns to step 5-4. Therefore, since the count value of the first space SPi is stored in the second area width storage part M1, the address of the comparison reference value N2 corresponding to the space of the first character set in the storage part M5 is stored. Referring to this, a comparison reference value N2 of the space of the first character is set in the register D*E reg in CPUZ from the storage unit M2. Then, the magnitude relationship between the second data stored in the area width storage unit Ml, that is, the count value corresponding to the width of the first space SPI, and the space comparison reference value N2 set in the register D@Ereg is determined. compare. As a result of this comparison, if the count value of the space SPI is larger than the comparison reference value N2, it is determined to be a binary value "1", and if not, it is determined to be a binary value "0". As a result, the binary value "l" or "0" is stored in the temporary storage M4.

In the twelfth example, the first space SPl is narrow,
Since the count value is not greater than the comparison reference value N2, a binary value of "0" is stored. After the value of D is subtracted by 1, the process moves to step 5-9. By repeating this operation, data comparison between the bar and space for the first character and the inter-character space is performed.

Also, when it is determined that D=0 in step 5-9,
In step 5-12, the first 7 bits of the data for one character stored in the temporary storage section M4, that is, the content corresponding to the bar and space data excluding the inter-character space C5, is read out from the data storage section M3.
Store in. Then, in step 5-13, the storage unit M
Clear the address data of the comparison reference value of the first character set to 5 and set it as the comparison base of the next character? T!
! The address data of the value is set, and the number of digits A of the character is subtracted by 1 in step 5-14. Next, in step 5-15, it is determined whether this number of digits A is O or not. If it is not O, steps 5-3 to 5-15 are repeated to sequentially compare bar and space data for each character. The data obtained as a result of this comparison are stored in the read data storage section M3 in a predetermined order. Note that the final character does not have an inter-character space C3 and the total number of bars and spaces is 7, so the eighth binary value determined in step 5-6 is completely meaningless. , this eighth binary value is discarded in step 5-12, so no problem arises.

In this way, when data comparison of all characters (- and spaces) and data storage of the comparison results are completed, the number of digits A of characters becomes 0, and the process moves to step 2-4 in FIG.

In this step 2-4, the read data storage section M3
Seven bits of data corresponding to the first character stored in is set in register A reg in CPUZ. Then, in step 2-5, the 13th
7-bit code r00 corresponding to “¥” shown in the figure
11000J is called from the program storage circuit 3 and set in the register B reg in CPUZ.

Next, in step 2-6, the contents of A reg and Breg
, that is, it is determined whether the first character is "\". Actually, register A
Since the data set in reg is equivalent to "1", it is determined that Areg==Breg, and the process moves to step 2-7, where comparison with all the codes shown in Figure 13 is performed. A determination is made as to whether the process is complete. If the comparison with all codes has not been completed, the next code corresponding to "-" is set in B reg, and then the comparison of Areg=B reg is performed again. By repeating this operation, ro is added to B reg.
oo.

011” is set A reg = B r
eg cy) condition is satisfied, and in step 2-9 B
The character "1" corresponding to the code set in reg is set at a predetermined location in the storage section M5.

Next, after clearing the flag set at a predetermined location in the storage unit M5, it is determined in step 2-11 whether decoding of all characters has been completed, and if not, the read data is stored. Seven bits of data corresponding to the second character stored in section M3 is set in register Areg. This second character is also determined in the same manner as the first character described above, and the character "2" is set at a predetermined location in the storage section M5.

Next, 7 bits of data corresponding to the third character are set in register A reg, and register B r
A comparison is made with the codes below ``\j'' that are set in eg sequentially.However, for the third ``/'', 3 out of 4 bars are wide and all 3 spaces are narrow. It is a special character and has a different structure from standard characters consisting of numbers, etc. Therefore, in the standard value calculation of the standard character shown in Figure 4, an accurate standard value is not calculated, so the 7-bit data corresponding to the third "/" is converted to rlol as shown in Figure 13.
ooolJ is narazuro o o o o.

It becomes "O".

If the data is ro O00000J in this way, even if steps 2-6 to 2-8 in Fig. 2 are repeated and the comparison operation with all codes is completed, the A reg and B reg The contents do not match, and a decoding error is determined. If a decoding error occurs, step 2-1
In step 3, it is determined whether or not the special character has been decoded by checking whether the flag in the storage unit M5 is "l". If it is determined that the special character has not been decoded, step 2-14 Start standard value calculation for special characters. Next, reference value calculation for this special character will be explained with reference to FIG.

First, in step 6-1, the count values of four bars corresponding to the character currently being decoded are summed. and,
By dividing this total value by 3 to a preset constant 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 is stored in the storage unit M2. Then, the count values of the three spaces are totaled, and this total value is divided by 4 to a preset constant stored in the program storage circuit 3, thereby obtaining the space comparison reference value N4 in the storage section M.
Store in 2. The above comparison standard value N3 is "," to "/
The constant 3 is set to 5 so that the count value corresponding to the narrow bar and the count value corresponding to the wide bar are approximately the middle value, and the comparison reference value N4 is the count value corresponding to the narrow space. The constant 4 is set to 1.5 so that the value is approximately halfway between the numerical value and the count value corresponding to the wide space.

When the calculation of the reference value of the special character is completed in this way, 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 l characters D=
8 at a predetermined location in the storage section M5. Then, in step 7-2, it is determined whether the first count value of the character currently being decoded stored in the area width storage section Ml is a bar or a space. If it's a bar.

The bar comparison reference value N3 stored in the storage unit M2 is
Set in register D m E reg in PUZ. Next, in stay and poor 4, the count value of the first bar of the character currently being decoded, which is stored in the area width storage unit Ml, and the register D a in step 7-3.
A comparison is made with the comparison reference value N3 of the bar set in E reg, and if the counted value is greater than the comparison reference value N3, the first bar is determined to be a binary value "1", and the counted value is set to the comparison reference value. If it is not larger than N3, it is determined that the binary value is "0". These binary values rlJ or "0" data are stored in the temporary storage section M4. After D is subtracted by 1, it is determined in step 7-7 whether D=0, and if it is not O, the process returns to step 7-2.

Next, in step 7-2, it is determined that the second count value is a space, and a space comparison reference value N4 is set in a predetermined register D e E reg in the CPUZ from the storage unit M2. 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 space comparison reference value N4 set in the register DmEreg. Compare. As a result of this comparison, if the count value of the space is larger than the comparison reference value N4, it is determined to be a binary value "1", and if not, it is determined to be a binary value "0". As a result, the binary value "1"
Alternatively, rQJ is stored in temporary storage M4. After the value of D is subtracted by 1, the process moves to step 7-7. By repeating this operation, data comparison between bars and spaces for the character currently being decoded and spaces between characters is performed. Further, if it is determined that D=0 in step 7-7, it is assumed that the data comparison has been completed, and the process moves to step 2-16 shown in FIG.

In step 2-16, the first 7 bits of the data for the special characters stored in the temporary storage M4, that is, the contents corresponding to the bar and space data excluding the intercharacter space C5, are stored in the register in the CPUZ. Set A reg. And set the flag to rlJ
and after setting the first code in B reg, by repeating steps 2-6 to 2-8, the character currently being decoded, that is, the third character shown in FIG. It is recognized that there is, and its contents are set in M5 in step 2-9.

When the above set is completed, the flag is cleared and A re
The next character data, that is, the fourth character data is set in g. The fourth and third character data are decoded in the same manner as the first and second character data. When all five characters shown in FIG. 12 have been decoded in this manner, it is determined in step 2-11 that all characters have been decoded.

The decoded contents "r12/23" are displayed on the display section 8 via the display control circuit 6 shown in FIG.

In addition, if the character cannot be recognized even after decoding the special character, that is, if the flag is "1" even though all the codes have been compared, this is determined to be a reading error and the display screen 8 displays in step 2-19. After displaying an error and clearing the flag, the process returns to step 2-1.

In the manner described above, standard characters such as "\J, r-", "r digit", and special characters such as "," to "/" can be read accurately.

Note that "a" to "e" only have one more wide space than standard characters! ! :4
It can be read in the process of decoding quasi-characters, but it can also be decoded by calculating a comparison reference value using the most suitable special constant in the same way as for "," to "/" described above. In particular, these raJ to reJ are often used as start codes and end codes, so it is also possible to force only the first and last characters to use the above special constants to calculate the comparison reference value. It is.

Next, an eight-code reading method that is an improved version of the second reading method described above 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-mentioned embodiment explained using FIG. 3, so the explanation will be omitted.

As a result of the above counting operation, a value corresponding to the width of the desired area consisting of each bar and space of the entire barcode as shown in FIG. 12 is stored in the area width storage section Ml. When the counting operation is completed, step 8-
Let us move on to the calculation of the total value of the standard characters indicated by 2.

This total value calculation will be explained with reference to Figure 9.
First, in step 9-1, the number of character digits A of the entire barcode is determined. This number of digits A of characters represents how many characters the entire barcode is made up of, and the obtained number of digits A is set in a predetermined location in the storage section M5.

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

This completes the calculation of the total values PI and P2 corresponding to the bar and space for the first character, and the number of digits A of the character is subtracted by 1. Then, it is determined whether this number of digits A has become O, and if it is not O, steps 9-3 to 9-8 are repeated to calculate the total value of bars and spaces corresponding to subsequent characters. and are respectively stored in the storage unit M2. Also, the number of digits A
is determined to be 0, the / of the entire barcode is determined to be 0.
It is assumed that the calculation of the total value corresponding to the spaces and spaces is completed, and the process moves on to the standard character data comparison shown in step 8-3.

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

First, in step 10-1, the number of character digits A is set again, and the total value PL of the first character is set again.
The address of the storage section M2 where P2 is stored is set in the storage section M5. Once this set is complete, step 10-
3, the total number of bars and spaces for one character D=8 including the inter-character space C5 is stored in the storage unit M5.
Set it to the specified location.

Then, in step 10-4, it is determined whether the first total value stored in the storage section M2 is a bar or a space. If it is a bar, the address of the total value of the first character set in the memory section M5 is referred to, and the total value P1 of the bar of the first character stored in the memory section M2 is stored in the register D m in CPUZ. E re
g, and in step 10-6, the bar comparison value Ql previously stored in the program storage circuit 3 is set in the (7) register H*L reg in the CPUZ.

When the setting of the comparison value Q1 is completed, in step 10-7, the quotient is calculated by dividing the total value P1 of the bars of the first character by the count value of the first bar BAI, and the comparison value of this calculated value and the bar is calculated. A comparison is made in size with Q1. As a result of the comparison, if the calculated value is greater than the comparison value Q1, the first bar is determined to be a binary value of "0", and if the calculated value is not greater than the comparison value Ql, it is determined to be a binary value of "1". . The data of these binary values rlJ or rQJ is stored in the temporary storage section M4.
Stored in In the example of Figure 12, the first bar BAI
is narrow and its calculated value is greater than the comparison value Q1, so the binary value "0" is stored, and after D is subtracted by 1, it is determined whether D=0 in step 10-10. After that, if it is not O, the process returns to step 10-4. Therefore, since the count value of the first space SPI is stored in the second area width storage part M1, the total value P2 of spaces for the first character is set from the storage part M2 to the register D e E reg, and step 10-
At step 12, the space comparison value Q2 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 quotient is calculated by dividing the total space value P2 of the first character by the count value of the first space SPI, and this calculated value and the comparison value Q2 are calculated. A comparison is made in size. As a result of this comparison, if the calculated value is larger than the comparison value Q2, it is determined to be a binary value "0", and if it is not larger, it is determined to be a binary value rlJ. As a result, the binary value rlJ or "0" is stored in the temporary storage section M4. In the example of FIG. 12, the first space SP1 is narrow, and its calculated value is the comparison value Q2.
Since the value is greater than 0, the binary value ``0'' is stored. and,
After the value of D is subtracted by 1, the process moves to step 10-10. By turning this operation green again, data comparison between the bar and space for the first character and the inter-character space is performed.

The comparison value Ql is set to approximately the midpoint between the total value of the bars 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 Q2 is set by dividing the total value of the bars by the count value of the wide bar. It is set to approximately the middle 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 data comparison of bar and space for one character is completed and it is determined that D=O in step 1O-1o,
The first 7 bits of data for l characters stored in the temporary storage unit M4 in step 10-14,
In other words, the data storage unit M reads the contents corresponding to the bar and space data excluding the inter-character spaces CS.
Sudoor to 3. Then, in step 10-15, the address data of the total value of the first character set in the storage section M5 is cleared, and the address data of the total value of the next character is set, and in step 10-16, the address data of the total value of the first character is cleared. Subtract 1 from the number of digits A. Next, step 10-
In step 17, it is determined whether the number of digits A of the lever is 0, and if it is not 0, steps 10-3 to 10 are performed.
-17 is repeated to sequentially compare bar and space data for each character, and the data obtained as a result of this comparison is stored in the read data storage M
3 in a predetermined order. Note that the final character does not have an inter-character space C5 and the total number of bars and spaces is 7, so the eighth binary value determined in step 10-7 is completely meaningless. , this eighth binary value is discarded in steps 10-14, so no problem arises.

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

In this step 8-4, the read data storage section M3
Seven bits of data corresponding to the first character stored in is set in register A reg in CPUZ. Then, in step 8-5, the thirteenth
7-bit code r00 corresponding to “¥” shown in the figure
11000J is called from the program storage circuit 3 and set in the register B reg in CPUZ.

Next, in step 8-6, the contents of A reg and Breg
, that is, it is determined whether the first character is "\". Actually, register A
Since the data set in reg corresponds to rLJ, it is determined that Areg is not Breg, and the process moves to step 8-7 to determine whether the comparison with all the codes shown in FIG. 13 has been completed. A judgment will be made. If the comparison with all codes is not completed, click the following "-
" After setting the code corresponding to "Are
A comparison is made: g=B rag. By repeating this operation, B reg becomes roooooit.
With J set, the condition A reg = B reg is satisfied, and in step 8-9, the character "1" corresponding to the code set in B reg is written.
It is set at a predetermined location in part i M5.

Next, after clearing the flag in the storage unit M5, it is determined in step 8-11 whether decoding of all characters has been completed, and if not, the read data is stored in the read data storage unit M3. 7 bits of data corresponding to the second character in the character are set in register A reg. This second character is also determined in the same manner as the first character described above, and the character "2" is set at a predetermined location in the storage section M5.

Next, 7 bits of data corresponding to the third character are set in register A reg, and register B r
A comparison is made with the codes sequentially set in eg.

However, the third "/" is a special character in which three of the four bars are wide and all three spaces are narrow, and its structure is different from standard characters consisting of numbers and the like. Therefore, since accurate data is not created in the data comparison of the standard character shown in No. 101, the 7-bit data corresponding to the third "/" is rlolooolJ as shown in FIG.
Instead, it becomes incorrect, such as rllllollJ.

If the data is "rlllloll" in this way, even if steps 8-6 to 8-8 in FIG. 8 are repeated and the comparison operation with all codes is completed, A reg and B
The contents of reg do not match and a decoding error is determined. If a decoding error occurs, it is determined in step 8-13 whether or not the special character has been decoded by checking whether the flag in the storage unit M5 is rlJ. If so, the special character data comparison in step 8-14 is started.

Next, we will discuss the data comparison of this special character in the 11th section.
This will be explained with reference to the figures.

First, in step 1 it, a total of bars and spaces for the character character aD=8 is set at a predetermined location in the storage section M5. Then, in step 11-2, it is determined whether the first count value of the character currently being decoded stored in the area width storage unit Ml is a bar or a space. If it is a bar, the total value P1 of the bars of the character currently being decoded stored in the storage section M2 is set in the register D++E reg, and in step 11-4, the total value P1 of the bars of the character currently being decoded is stored in the memory section M2, and in step 11-4, the total value P1 of the bars of the character currently being decoded is stored in the memory section M2. The comparison value Q3 of the special character bar is set in the register He L reg.

When these sets are completed, in step 11-5, a quotient is calculated by dividing the total value Pl of the bars of the character currently being decoded by the count value of the first bar, and a comparison value Q3 between this calculated value and the bar is calculated. A comparison is made in size. As a result of the comparison, if the calculated value is greater than the comparison value Q3, the first bar is determined to be a binary value of "0", and if the calculated value is not greater than the comparison value Q3, it is determined to be a binary value of "1". . These binary values "1" or rQJ data are stored in the temporary storage section M4. In the example of FIG. 12, the first bar is wide and its calculated value is not greater than the comparison value Q3, so the binary value rlJ is stored.

After D is subtracted by 1, it is determined in step 11-8 whether D=O, and if it is not O, the process returns to step 11-2. Therefore, when it is determined that the second count value is a space, the total space value P2 of the character currently being decoded is set in the register DφE reg from the storage unit M2, and the step tt-to
The comparison value Q4 of the special character space stored in advance in the program storage circuit 3 is stored in the register H.
@ Set to L reg.

Then, in step 11-5, a quotient is calculated by dividing the total space value P2 by the count value of the first space currently being decoded, and a comparison is made between this calculated value and the comparison value Q4. As a result of this comparison, if the calculated value is larger than the comparison value Q4, it is determined to be a binary value "0", and if it is not larger, it is determined to be a binary value "l". As a result, the binary value “1
” or “0” is stored in the temporary storage unit M4. 1st
In the example of FIG. 2, the first space is narrow and its calculated value is greater than the comparison value Q4, so a binary value of "0" is stored. Then, after the value of D is subtracted by 1, step 1
Move on to 1-8. By repeating this operation, data comparison between the bar and space for the first character and the inter-character space is performed.

The comparison value Q3 is set to approximately the midpoint between the total value of the 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. The total value of spaces in is set to approximately the midpoint between the value obtained by dividing the total value of spaces by the count value of narrow spaces and the value obtained by dividing the count value of wide spaces.

” If it is determined that D=O in step 11-8, it is considered that the data comparison is completed,
Proceed to step 8-15 shown in FIG.

In step 8-15, the first 7 bits of the data for the special characters stored in the temporary storage M4, that is, the contents corresponding to the bar and space data excluding the inter-character space C5, are stored in the CPUZ. Set in register A reg. And set the flag to r
After setting IJ and setting the first code in B reg, repeating steps 8-6 to 8-8 determines that the character currently being decoded, i.e. the third character shown in FIG. 12, is "/". This is recognized and its contents are set in M5 in steps 8-9.

The flag is cleared when the above set is completed.

The next character data, that is, the fourth character data is set in A reg. The fourth and third character data are decoded in the same manner as the first and second character data. When all five characters shown in FIG. 12 have been decoded in this way, it is determined in step 8-11 that all characters have been decoded, and the decoded content "12/23" is shown in FIG. The image is displayed on the display section 8 via the display control circuit 6.

Note that if the character cannot be recognized even after decoding the special character, that is, if the flag is "1" even though all the codes have been compared, it is assumed that a reading error has occurred and the display section 8 is displayed in step 8-18. After displaying an error and clearing the flag, the process returns to step 8-1.

In the above manner, ``¥J, r-J, r
Standard characters consisting of numbers, etc., and characters from , to /
” can be read accurately. Also, regarding “a” to reJ, the above “,
” ~ Prepare the most suitable comparison value in the same way as “/” and select “,
” to “/” can be decoded in a special character decoding process different from that of “/”.

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

(Effects) As described above, in the present invention, values corresponding to each region consisting of bars and spaces are stored by operating a barcode with a reader, and a standard value is determined based on the stored value of each region width. Each character is decoded in the character decoding process, and any character that results in a decoding error in the standard character decoding process is decoded again in the special character decoding process. Therefore, not only standard characters but also special characters can be reliably read, and there is no need to make a complicated judgment in advance as to whether a character to be decoded is a standard character or a special character.

[Brief explanation 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. 2 is a block diagram showing a circuit diagram of a reading device. 3 is a flowchart showing the counting operation, FIG. 4 is a flowchart showing the standard value calculation operation of the standard character, FIG. 5 is a flowchart showing the data comparison operation of the standard character, and FIG. 6 is a flowchart showing the standard value calculation operation for special characters, FIG. 7 is a flowchart showing the data comparison operation for special characters, and FIGS. 8 to 11 show the second embodiment.
Figure 9 is a flowchart showing the entire reading operation, Figure 9 is a flowchart showing the total value calculation operation for standard characters, Figure 10 is a flowchart showing the data comparison operation for standard characters, and Figure 11 is data comparison for special characters. FIG. 12 is a flow chart showing the operation, FIG. 12 is a diagram showing an example of a bar code, and FIG. 13 is a code table of the bar code shown in FIG. In the drawing, 2...CPU 3-...Program storage circuit No. 4/Meeting data storage circuit 6...Meeting reader 8...Display section

Claims (1)

[Claims] (1) In a barcode reading method for reading a barcode in which at least one of alternately arranged bars and spaces has two or more widths, and a bit value is expressed depending on the width. , by scanning the barcode with a reader, a value corresponding to the width of each area consisting of bars and spaces is stored, and based on the stored area width value, each character is decoded in a standard character decoding process. A bar code reading method is characterized in that a character that causes a decoding error in this standard character decoding process is decoded again in a special character decoding process.