JPS58225487A - Bar code reader - Google Patents

Abstract

PURPOSE:To read only normal bar code by disregarding the lead-off data of data in one character if an error occurs in decoding and the data has an extremely large width value. CONSTITUTION:One character data obtained by scanning a bar code with a hand scanner 1 is inputted to a CPU5 through an A/D converting circuit 2, pulse detecting circuit 3, and AND gate 4. The CPU5 decodes the one character data and if an error occurs in decoding, whether the data has an extremely large width value or not is detected. If the extremely large width value is found in the data, the lead-off data of the one-character data is disregarded to decode again one-character data to be led-off with the next data.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a barcode reading device that reads barcode information from a medium in which character information is recorded as a barcode.

Conventional 1 This type of device, for example, irradiates light onto a medium on which predetermined character information is recorded (printed) as a black and white barcode, and converts the difference in light reflectance into an electrical signal (size of current). Optical reading devices that read barcode information have been put into practical use.

This type of optical reading device has the advantage of being cheaper than media such as magnetic tape and magnetic cards because it only needs to print the Nihar code on ordinary paper, and it is also useful for electronic cash registers, etc. It is widely used as a data input means for PO8 systems.

By the way, there are various types of barcodes used in this type of reading device. For example, NW-7 is a black and white barcode (bright/dark) with a narrow width.
Each character consists of four black bars and three white bars. This NW-
7, a blank space that is much wider than the width of the barcode may be inserted between predetermined characters. For example, if this code format is used for a price tag, the blank above will be
It may be inserted between the product code, etc. and the price. In this type of device, when changing the price on a price tag, a small piece of paper on which the price is printed in the form of a bar code is pasted onto the price area with the blank space as the border. Therefore, in such a case, if the pieces of paper to be pasted together are thick, there is a risk that the edges of the pieces of paper within the blank space may be read as black bars.

This invention was made against the background of the above-mentioned circumstances, and its purpose is, for example, to ensure that accurate barcodes are used even when the price is changed by pasting a piece of paper on top of the price tag. An object of the present invention is to provide a barcode reading device that reads barcodes.

Hereinafter, the present invention will be specifically described based on an embodiment shown in the drawings. 1 in the figure indicates a manually operable hand scanner. This hand scanner 1 converts the reflectance of light (strength of light) when a barcode is irradiated into an electrical signal (magnitude of current), and converts it into an A/D (analog/digital) conversion circuit 2.
Output for. The digital signal (rectangular wave signal) converted by the A/D conversion circuit 2 is input to the pulse detection circuit 3. The pulse detection circuit 3 outputs a trigger in synchronization with the rise and fall of the input rectangular wave pulse.
is input as an interwoven signal 1NTI.

The CPU 5 includes FL and FW registers that store x, y, zt, registers and flags for calculation, and B and 8 that store data.
In addition to having various registers such as registers, memory M
When writing and reading data to and from the memory M, the configuration includes an address section AV for storing write address data of the memory M, an address section AR for storing the write address data of the memory M, an address section AR for storing the write address data, and a logic operation circuit ALU. It becomes. Then, the CPU 5 outputs control signals to the S and Rλ input terminals of the SR type flip-flop (SR-FF) 6, respectively, and sets the 5R-FF 6. This 5R-FF6 converts its Q output into an AND gate 4
It is applied to the other input terminal of , and controls the opening and closing of the acid gate 4. Further, the CPU 5 uses a time counter T
The count value data obtained at step o is read, and a clear signal C- is output to the time counter TO. The time counter To counts fleck signals of a predetermined frequency and is 9, and the count value data read into the CPU 5 corresponds to the time interval from when the interwoven signal lNTl is input to the CPU 5 until the next interwoven signal lNTl is input. do. Also, the time counter TO sends the carry signal to the CPU.
5, the interlaced signal INT and [ are output. Furthermore, the CPU 5 is connected in each direction so that it can exchange data with the memory M, and can also exchange data with the data memory D.

The memory M is configured, for example, by a RAM (random access memory) and executes writing and reading of data. That is, an area of the memory M that is addressed according to the contents of the address section AV has a time counter. Count value data from Tc is written through 0PU5, and data in the area of 5 memory M, which is addressed according to the contents of address section A, is read to 0PU5.

The contents of data memory D include, for example, 0PU5 outputs a strobe signal ST to ll0R (1! slave type cash register) not shown, and data transfer request signal aO is input to 0PU5 from E, :a i side. Sometimes 0P
The data is transferred from U5 to the KOR side as data DT. Note that the 0PU5 outputs a sound command to the speaker 7 to notify the error.

Next, the operation of the above embodiment will be explained. Now, assume that a barcode expressed in the code format of MW-7 is to be read. For example, as shown in Figure 2, this NW-7 has character information of numbers and symbols expressed in a 7-bit binary code, and also has four black bars and three white bars (a total of seven bars). A barcode (bar) constitutes one character, and regardless of whether it is a black or white bar, a binary ``0'' is represented by a narrow bar and a ``1'' is represented by a wide bar.

And the black bars and white bars are arranged alternately,
The black bar is arranged at the beginning.

If you use NW-7 bar food like this on the price tag,
For example, as shown in FIG. In this case, in the NW-7 for hand scanner reading, the data length is a maximum of 20 characters, and the barcode area A for the product code etc. and the barcode area B for the price are separated, and there are 0 blank spaces between them. In addition, a left margin is provided at the left end of the price tag, as well as a barcode area for the start code, and a right margin is provided at the right end of the price tag, as well as a stop code. A barcode area is provided. For such price tags, if you change the price by pasting a piece of paper on top of the price tag, the blank space will be 0.
The edge of the piece of paper may get stuck inside, and a black bar may be formed at the edge.

Figure 4 shows this state.
If a piece of paper is pasted on the price tag, Figure 4 (2)
~(9) shows two pieces of paper, and Figure 4 (10)~(19) shows the case of three pieces of paper stacked on top of each other. The position may be as shown in the figure. Note that the boxed area in the figure indicates the regular barcode area.

By the way, when a piece of paper is pasted on a price tag and a black bar as shown in Figure 4 (1) is formed at the edge of the piece of paper, when the price tag is scanned with hand scanner 1, A The output of the /D conversion circuit 2 is as shown in FIG. 5 (1). FIG. 5 (1) shows that the character "3" at the end of code area A shown in FIG. A / when scanning the first character "\" of code area B with
0 shows the output of the D conversion circuit 2, and indicates that the edge of the piece of paper in the blank area 0 has been read as a black bar b. , /D
When the output from the conversion circuit 2 is input to the pulse detection circuit 3, the output becomes as shown in FIG. It is input to 0PU5 via. As a result, the 0PU5 executes the interrupt processing of the interconnected signal NTI. In other words, when the interwoven signal NTI arrives, the 0PU5 increments the contents of the address field AV by 1, and then the count value of the time counter To. Read the data and write it to the area of the memory M that is addressed according to the contents of the address part Aw,
Subsequently, the process of clearing the contents of the time counter To is repeatedly executed every time the interconnected signal NTi is input. As a result, the count value data of the time counter TO read into the 0PU5 corresponds to the time interval of the pulses in the output of the pulse detection circuit 3, in other words, the width value of the black and white barcode area. They are sequentially written into areas of memory M. In this case, when the carry signal is output from the time counter TO, the 0PU5 executes the interrupt processing of the interconnected signal engineer NTII. by this,! 9R-FF6 is reset to disable the interrupt processing of the interconnected signal engineer NTi. That is, this process is executed, for example, when the next bar does not arrive even after a certain period of time has elapsed, and prohibits the barcode reading operation.

Thus, the main operation of 0PU5 is executed according to 74- in FIG. That is, first, when the power is turned on or after interrupt processing, step S is executed, and the memory M1 is
Initialization processing is executed to set initial values to the contents of various registers in data memory D and opU5. Next, step S! Then, set 5R-11'lP6 to open Antogame) 4, and connect Interconnected Signal Works NT.
Set the interrupt processing in (2) to an executable state. This causes the time counter T to be stored in the memory M.

In other words, the barcode width value data is read out by executing step 81. That is, the width value data is read from the area of the memory M addressed according to the contents of the address section AR and transferred to the X register. Next, the process proceeds to step si, and the process of incrementing the contents of the address field AR by 1 is executed to update the address.

Next, the process proceeds to step S, where it is checked whether the contents of the address field AR precede the contents of the address field AV.

In other words, since the read operation of data in the memory M must be executed without preceding the write operation, step S is a process to check whether the read operation is normal. Ba,
The contents of the address field AR exceed the contents of the address field Ay, and the process proceeds to the next step S, , S. Step S,,S
, is a process executed to read one character's worth of data from memory M. In NW-7, one character consists of seven barcodes, so the width is determined according to the seven barcodes. To read the value data, step S6
At step S, the contents of the Y register are incremented by +1, and then at step S, the contents of the Y register are
”, and if it is not “7”, the process returns to step S8, and steps S and S are repeatedly executed until the contents of the Y register become “7”.

When the process of reading data for one character from the memory M and transferring it to the X register is completed in this way, the process proceeds to the next step Ss, and the contents of the
Decode in LU and transfer the result to 2 registers. Next, the process proceeds to step S0, where it is checked whether or not an error has occurred in the decoding as a result of the decoding with the above-mentioned Suffix No. 8. If no error has occurred, the process proceeds to step S.

Proceed to O In this step 810, it is checked whether a start code has arrived, and if it is a start code, the process proceeds to step Sll and sets "1" in the FS register. In this step Stt, when the start code comes, step st! is executed to advance 70- through step 81°. Further, (step sty is to check whether the contents of the νLS register is "1", and is the same as step sl described above).

If it is determined that the start code is not the start code, the process returns to step Sa through step 812, and the above-described operations are executed until the start code is received.

If the barcode is scanned normally, the start code comes first, and the process proceeds from step Stt to Stella/Customer 8. Step SSS is for checking whether a stop code has been received. If the stop code has not been received, the process advances to step S14.

Here, the contents of two registers are transferred to data memory D. Therefore, the data memory D has the above-mentioned step SC.
Character information of decoded numbers or symbols is written. When such processing is completed, steps 8111 to S8111, which are preprocessing for executing error processing to be described later, are performed.
, move on to execution. That is, in step ste, the contents of the address section AR are incremented by 1, and data in the area of the memory M that is addressed according to the contents is saved in the S register. In this case, the data transferred to the S register is barcode F(7) data corresponding to the rear end (tail) of one character that is currently being decoded. Next, step 816 determines whether the data transferred to the S register is a narrow bar or a wide bar, that is, "0" or "
If it is "1", proceed to step S, 7, and set 91" in the FW register. If it is "0", proceed to step SI8, and set "OI'1" in the 7w register. Therefore, 1 depending on the contents of the FW register.
You can know whether the rear end bar of the character is a narrow bar or a wide bar. Facing step 81? Alternatively, following Flta, step S1. is executed, and after clearing the contents of the S register in advance, the process returns to step S1, and the same operation is repeated thereafter. That is, if the data for one character is read from memory M and decoded, and the decoding is successful, step 814 is executed until the stop code is received.
The character information read sequentially is written into the data memory 12, and by executing steps 816 to S4, the trailing bar of the character information read last time is
Narrow bar or wide bar is searched. Then, when the stop code is received, the process starts from step 818 to step st.
Proceed to step o, reset 5R-FF6, and disable interrupt processing of the interconnected signal engineer NTI. Next, proceeding to step s21, first, the strobe signal S is sent to the ICOR side.
Sends a data transfer request signal 00 from the l1liOR side.
When the signal CO arrives, the contents of the data memory D are serially transferred, for example, one character at a time, to the EoR side. After that, the process returns to step s1 and the same operation is repeated.

If the step island is not decoded and an error is determined, the process advances to step B22 and subsequent error processing is executed. That is, step S■ checks whether the rear end bar of one character that was successfully decoded last time is a four-bar or a wide bar, depending on the contents of the FW register, and
If the content of the W register is "1", that is, a wide bar, the process proceeds to step BIS; if the content is "0", that is, a narrow bar, the process proceeds to step 8+14. Step s! s multiplies the contents of the S register by a constant by 1, and also performs step s, 4
The contents of the S register are multiplied by a constant 1 cte, and the data in each S register is made into extremely wide value data. Then, step S, 3. S,, (When processing 71 is completed, the process proceeds to the next step s21+, where it is checked whether there is a bar thicker than the data in the S register in the data in the This is to check whether or not there is a very thick bar in the data in one character read this time by comparing it with the rear end bar of one character.

In this case, since the barcode is read with a hand scanner in this embodiment, the scanner speed may change. As a result, if the judgment in step 81!1 is made by comparing it with the previous rear end bar, then...
H' Speed 0: No difference, 1: High reliability.

Then, step S2. As a result, if it is determined that there is a very thick bar, it can be seen that the blank 0 part in FIG. 3 has been read. In this case, step s26. Go to S
The contents of the register are incremented by 1, and then the process proceeds to step "h7" to check whether the contents of the S register are "3". Step 811 like this? This process causes error processing to be executed up to three times based on the following reasons, which will be explained later, and as a result, the contents of the S register become "3".
”, the next step 826 is executed.

Here, processing is performed to increment the contents of the address field AR by "-5". Next, the process proceeds to step StO, the contents of the X register are cleared, and the process returns to step S. As a result, by executing step Sρ, among the data in memory M, the data in the first black bar of one character read this time is ignored, and decoding is restarted as data for one character from the data in the next black bar. . That is, by setting the contents of the address field AR to "-5" in step 821, the second black bar is read out, which means that the first black bar is canceled.

Therefore, for example, as shown in Figure 4, when a piece of paper is pasted on a price tag and the price is changed, 1 even if a black bar is formed at the edge of the piece of paper, the black bar should be ignored. I can do it. In this case, if there is one irregular black bar as shown in Fig. 4 (1) to (3), the first black bar is ignored and one character is added from the next black bar in the first error processing. If the decoding is restarted as data for 20 minutes, it can be immediately decoded to predetermined character information, but if there are two irregular black bars as shown in FIG. 4 (4) to (9), step SIl will cause an error in decoding again. Therefore, error processing 74- is executed again. In this case, step S! s is determined to be jyi sJ, so in step ste the contents of the S register are
2'', and the process proceeds to step 828- via step Sta.
After executing ``sho'', the process returns to step Ss and the same process is repeated. As a result, it is possible to similarly cancel the leading black bar (in this case, the second irregular black bar) and restart decoding from the next black bar (regular black bar). Similarly, as shown in FIG. 4 (10) to (19),
If there are 3 non-regular Kuronoku-, error handling should be done 3 times.
By repeating this process twice, the third irregular black bar can also be canceled. Then, when error processing is executed three times in a row, when the fourth error processing starts, the contents of the S register becomes "4", so the steps also change from step S to step S. The process proceeds to step s1, an error alarm is sounded, and the process returns to step s1. Therefore, when the error process is executed for the fourth time, the contents of each memory etc. are returned to the initial state by executing step s1, and the operator has to scan the price tag again. In other words, in aw-7, there are four black bars in one character, so if there are up to three black bars, it can be determined whether they are regular black bars or not, but if there are four non-regular black bars, Since it is impossible to determine whether the bar is a regular bar or not, the content of the S register is "4".
When this occurs, an error notification is performed in step Sso, and the operator is notified to scan the price tag again. Therefore, the determination in step 827 above is based on M
This takes into account the unique code format of Y-7.

Therefore, if it is determined that AV<AR in step 82B, and if it is determined that [oJ] in step 82B, the process returns to step S via step SSO.

In the above embodiment, the NW-7 code format and a hand scanner were used as an example, but other code formats may also be used. You can also do this.

As detailed above, according to the barcode reading device according to the present invention, if an error occurs in decoding as a result of decoding data for one character obtained by scanning a barcode, the data As a result, when it is detected that a very large width value is included, the first data of the data in that one character is Since the data for one character is ignored and the next data is decoded again, for example, if you change the price by attaching a piece of paper to a price tag, the edge of the piece of paper will be marked with a black bar. Even if it is formed as , the black bar can be ignored and only the regular barconide can be read.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with FIG. 1 being an overall block circuit diagram, and FIG. 2 being a diagram showing the code form of NW-7.
Figure 3 shows the barcode formed on the price tag;
The figure shows what happens when a piece of paper is pasted on a price tag and the price is changed.
A diagram showing the black bar formed by the edge of the piece of paper, FIG.
1) is the output waveform diagram of the A/D conversion circuit not shown in Figure 1 when the barcode on the price tag in the state shown in Figure 4 is read, and Figure 5 (2) is the output waveform diagram in Figure 1 in this case. The output waveform diagram of the pulse detection circuit shown in Fig. 6 is the OPU shown in Fig. 1.
3 is a flowchart showing the main operation of FIG. 1...Hand scanner, 2...A/
D conversion circuit, 3...Pulse detection circuit, 5...
...OPUSM, river, memory, To...
Time counter, D...Data memory. =498 4th ==0=21110 01.mouth 111 mouth 12.mouth 111 mouth 13.mouth 1110 ・14.mouth I 11 mouth (15.mouth I II- 06.mouth 1110 (17.mouth 1110, ,, S II 1 mouth... 9 mouth 1110

Claims (1)

[Claims] In a barcode reading device for reading barcode information from a medium in which a plurality of character information is recorded as a barcode and a space having a width much wider than the barcode is inserted between predetermined pieces of character information. , a reading means for reading the width value corresponding to the area of each bar of the barcode, a storage means for sequentially storing the width value data read by the reading means, and a width for one character stored in the storage means. a decoding means for generating predetermined character information based on value data; and a detection means for detecting whether or not a very wide value is included in the character information when an error occurs during decoding by the decoding means. and control means which ignores the first width value data in the storage means and restarts decoding from the next width value data when the detection means detects that a very wide width value is included. A barcode reading device comprising: