JPH01156886A - Bar code reader - Google Patents

Abstract

PURPOSE:To decrease an erroneous reading generation rate by calculating a multiplying factor L for the reference module width of a bar width, and then adding a deciding processing whether or not the calculated value L is in a prescribed range, and making the value into a reading error when it is out of the prescribed range. CONSTITUTION:A total sum Si of respective four bar widths Mi, Mi+1, Mi+2, and Mi+3 constituting one character is calculated, and a reference module width Ni is calculated. The multiplying factor for the Ni value of the respective four bars is calculated from the Ni value, and the L value (Li, Li+1, Li+2, Li+3) is made into an integer value. When the value of the L is larger than a prescribed range AX and smaller than AY, L=1 is obtained, when BX<L<BY, L=2 is obtained, when CX<L<CY, L=3 is obtained, when DX<L<DY, L=4 is obtained, and in other cases, the value is made into the decoding error. Thus, the erroneous reading of the bar code generated by the scattering of the printing accuracy of the bar code and the converting error of a converter, etc., can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a barcode reading device that optically scans and reads barcodes.

BACKGROUND OF THE INVENTION FIG. 3 shows a block diagram of a JAN barcode symbol established by JIS X-osol. In the figure, 1 is the left end space (start white margin), 2 is the right end space (end white margin), 3 is the start reference bar consisting of three black and white bars of the same width (reference module width N), and 4 is the start reference bar. A center base single bar consisting of six reference modules of black, white, black and white, 6 is an end reference bar consisting of three basic modules of black and white, 6 is a bar that constitutes a left character, and one character as shown in 8. consists of four black and white bars. Reference numeral 7 indicates a bar constituting the right side character, and as shown in 10, one character consists of four bars: black, white, white, and white. The bar width of the four bars that make up one character is Mt.

Ml+1. M, +2. If Mi+3, the total bar width Si for one character is Si=Mi+Mi+, -
+Ml+20Ml+3=7xN.

There are two types of JAN codes: the IANg quasi code, which consists of 6 characters each on the left and right sides, and the IAN abbreviated code, which consists of 4 characters.

(JAN standard code has 13 digits due to the composition of the six characters on the left to display the beginning of the country code. For details, refer to JIS X-oso1.) Figures 4 and 6 show the conventional bar code. The flow of code reading processing is shown. Fourth
In the figure, processes A and B are processes for searching for a candidate point for the start white margin 1. A white bar larger than a predetermined value is detected in the process and is assumed to be a candidate point for the start white margin. After detecting the candidate point of the start white margin with processing A and B, use processing T, WORK, O, FORCE, KI to set the start reference bar 3. A process is performed to determine whether the end reference bar 61 is the center reference bar 4 or not. When the above determination process is positive, the characters on the left are decoded in steps , , and , and the characters on the right are decoded in steps . If it is determined that the process is not possible, the process returns to process A and the start white margin candidate point detection process is performed again. Processing is JAN standard code decoding - a process of decoding the first character of the code. After completing the decoding of the left and right characters, a check digit is calculated and checked in the processing step. If the check digit is positive, the reading process is completed. FIG. 6 shows the flow of decoding processing for one character. In the fourth time, the processing section calculates each '9-width M1, M1+1, Mi+2 of the four bars constituting one character.
・Sum of Mt+s.

The process to calculate the standard module width Ni constituting one character, the process to calculate the standard module width Ni that constitutes one character, and the process to calculate the Ni value of each of the four bars from the standard module value Ni, Li+1=Mi+L, L Lla i
+1 i+2- The process of calculating i+3, the processing is Lt, Lt-4-4, Lt+2tLi-1-3, rounding off the value to an integer, and then converting it into an integer Li*Li-
1-1*Li+2-Li+3 This is a process of decoding one character into numerical data based on the value.

Problems to be Solved by the Invention As shown in the flows of FIGS. 4 and 6, in the conventional example, Li,
Li+1=Mi+ya1 # Li-1-2m Li+3
The value is rounded to an integer and then decoded. However, converting to integer values by rounding has the disadvantage that if the accurate bar width cannot be input due to variations in printing accuracy or conversion errors in the barcode data input converter, the barcode may be misread. There is.

Means for Solving the Problems In order to solve the above problems, the present invention provides a converter that scans a bar code and converts the bar width information of the bar code into an electrical signal, and a converter that converts the bar width information of the bar code into an electric signal. A conversion circuit that converts information into numerical data corresponding to the information, a memory that stores the numerical data, and a microprocessor that processes the data stored in the memory and decodes the barcode, and the microprocessor includes: Width MW of the four bars 1+11-1-2 Mt-1-3 that make up one character, M Total sum Sl(Si-Ml+Mi+1+Mi+20Ml+
3), a second calculation means for calculating a standard module value N1 (Nl=8./7) for one character from the Si value, and a standard for each bar constituting the one character. Multiplier Li:Mi for module value Ni
/Ni-Li+1='i+1/Ni *Li+2=M
l + 2/N L・LL-1-3=Town+3/N1, and the Li, Li+1=Li+2iLi+
3. After calculating the LLi+1=Mi+LL, the f-direction processor of the microb 1 i+1 i+2e 13 determines whether the calculated value is within a predetermined range. The above calculation value *-i+1s
i+2s i+3 falls within the predetermined range, and L
This is a barcode reading device that determines a decoding error when LL is not present.

Effect: The above configuration prevents barcode reading failures (erroneous readings) of the barcode reading device caused by variations in barcode printing accuracy, conversion errors of the converter, and the like.

Embodiment FIGS. 1 and 2 are block diagrams and processing flowcharts of an embodiment of the barcode reading device of the present invention. An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 4. In Figure 1, 61 is a barcode, s3
62 is a converter (sensor) that scans the barcode label 61 and converts the bar width information into an electrical signal; 62 is a lens that forms an image of the barcode on the barcode label 61 onto the converter 63; and 64 is a converter. A conversion circuit converts the output of the converter 63 into numerical data corresponding to bar width information, 66 is a memory that stores the numerical data, and 66 processes information in the memory 66 that stores scanning start commands and scanning information for the converter. A microprocessor 67 decodes the barcode information, a timing generation circuit 67 generates drive pulses for the converter 63 according to instructions from the microprocessor 66, and an LED 68 illuminates the barcode. In this embodiment, a one-dimensional image sensor is used as the converter 63. As shown in the flowchart of FIG.

After detecting the start white margin 1 of the barcode using the power and key keys, the right character is decoded using the process, ke, and ko, and the right character is decoded using the process. The decoding process for each character will be explained using FIG. The processing section is the bar width Mi of each of the four bars that make up one character 5M1
-4-1, Mi+2. A process of calculating the sum S1 of Mi+3. Process 4 is a process for calculating the reference module width N1.

In the processing, the multiplier for the Ni value of each of the four bars is calculated from the Ni value.
i-1-1・Li+2・L1+3) is an integer value, if the value of L is larger than the predetermined range Ax and smaller than Aa, L=1, and if larger than Bx and smaller than Ba, L=2 , C! If larger and smaller than Ca, L=3, D! If it is larger and smaller than D, then L=
4, and other cases are treated as a decoding error.

In this embodiment, Ax * A, B, B, C,,C
A, D! , D A, A! =0.5, Ay=1.4
, B, = 1.6, B,: 2.4°C: 2.6. C
=3.4. D=3.6. D, = 5.0.

The I y x processing is a process of decoding one character into numerical data from the integer L value (Li, Li+1.Li+2°Li+1=Mi++3 value).

As shown in this example, after calculating the magnification of the bar width with respect to the standard module width, a process is added to determine whether the calculated value is within a predetermined range, as shown in the processing diagram. By determining a reading error when the value is outside the range, the barcode reading device of the present invention can reduce the rate of misreading to 1/1o or less compared to conventional reading devices.

Effects of the Invention As described above, the present invention has an excellent effect of reducing barcode reading failures (misreading) due to misalignment of barcode label printing and conversion errors of barcode bar width data converters. .

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a barcode reading device showing an embodiment of the present invention, FIG. 2 is a flowchart showing the processing of the same device, FIG. 3 is a configuration diagram of a JAN barcode, and FIGS. 4 and 6 The figure is a flowchart showing the reading process of a conventional barcode reading device. 1...Left end space (start white margin),
2...Right end space (end white margin), 3
...Start reference bar, 4...Center reference bar, 6...End reference bar, 6...
...Character on the left, 7...Character on the right, 8,9...1 character on the left, 10.11.
...1 character on the right side, 61...Barcode label, 62...Lens, 63...
・Converter, 54... Conversion circuit, 66...
・Memory, 66...Microprocessor, 67
...Tie generation circuit, 68...L
ED0 Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure 5 Tono V-Cor V Al 52 --- Red λ' B-LED Figure 2 Rakuge 7-＠fl〒nytt 8・9゛-＼Left (111f〒γ17ta10.1l--
One shoulder, one ear, one h) 7 da Fig. 4

Claims (1)

[Claims] a converter that scans a barcode and converts the bar width information of the barcode into an electrical signal; a conversion circuit that converts the electrical signal into numerical data corresponding to the bar width information; and a memory that stores the numerical data. and a microprocessor for processing the data stored in the memory and decoding the barcode, and the microprocessor has four bar widths M_i, M_i_+_ that constitute one character.
1, M_i_+_2, M_i_+_3 total Si (Si
=M_i+M_i_+_1+M_i_+_2+M_i_
+_3), and a first calculation means for calculating a reference module value N_i (N_i=S
_i/7), and a magnification L_i=M_i/N_i, L_i_+_1=M_i of each bar constituting the one character with respect to the reference module value N_i.
___+_1/N_i, L_i_+_2=M_i_+_2/
a third calculation means for calculating N_i, L_i_+_3=M_i_+_3/N_i; and said L_i, L_i_+_1,
and decoding means for decoding the L_i_+_2, L_i_+_3 values into numerical information, and the microprocessor is configured to decode the L_i, L_i_+_1, L_i_+_2, L_i_
After calculating the value of +_3, a process is performed to determine whether the calculated value is within a predetermined range, and the calculated value L
_i, L_i_+_1, L_i_+_2, L_i_+_
A barcode reading device that determines a decoding error if 3 is not within a predetermined range.