JP2732909B2 - Barcode reader - Google Patents

Description

[Contents] Outline Industrial application field Conventional technology (FIGS. 4 to 7) Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Action Embodiment (FIGS. 2 and 3) Effects of the Invention [Overview] The present invention relates to a bar code reading apparatus, which aims to accurately demodulate a bar code even when the white margin outside one guard bar is insufficient. In a bar code reading device provided with guard bars on both sides and reading a bar code having a white margin set outside the guard bar, a margin check means for detecting a white margin of the bar code, and a guard bar check for detecting a guard bar of the bar code Means, character configuration checking means for detecting that the character configuration of the barcode is correct, and a demodulation means for demodulating the barcode. And when the barcode is read,
The bar code can be demodulated when the margin check unit detects that a white margin of a specified length exists outside at least one of the guard bars.

[Industrial applications]

The present invention relates to a bar code reader, and more particularly to a bar code reader capable of accurately reading a bar code even when a white margin outside one guard bar is small.

[Conventional technology]

In response to the recent development and spread of computer systems, POS (Point O
f Sale) method is widely used. POS terminal devices are arranged at each sales floor, and each time a product is sold, an operator at each sales floor reads the barcode printed on the label of the product with these POS terminal devices, decodes the product number, product name, etc., The price is displayed. The POS terminal device calculates and outputs the total price of the product, notifies the sales information host computer, and manages the product accordingly.

Incidentally, the barcode is configured as shown in FIG. 3, for example. Fig. 4 shows an example of a standard version consisting of 13 digits, a left margin of 7 modules or more (11 modules in Fig. 4), a barcode of 95 modules, and a module of 7 modules or more (Fig. 4 (7 modules). The bar code consists of a three-module guard bar with black and white basic unit width from the left,
6 character (1 character 7 module) left data character, 5 module center bar of basic unit width of black and white, black and white, 5 character (1 character 7 module) right data character, 1 character (7 module) modular check character And a three-module guard bar having a basic unit width of black and white.

By the way, the data character on the left side is composed of a combination of odd parity (the sum of the number of modules in the black bar is an odd number) and even parity (the sum of the number of modules in the black bar is an even number), or consists of only the odd number variance. The first digit of the prefix character, that is, the first character (the fourth character) depends on the combination state of odd parity and even parity.
In the example shown in the figure, “4” written in the left margin portion is determined. The right data character and modular check character are composed of even parity.

In the abbreviated version, characters on the left side of the center bar are composed of odd-numbered parities, and characters on the right side are composed of even-numbered characters.

The configurations of these barcodes are all well-known, and further description will be omitted.

When reading a barcode configured in this way, since the barcode is separated by the left guard bar, the center bar, and the right guard bar, a half block between the left guard bar and the center bar, that is, the left block, and the center bar and the right bar It is configured such that it can be read even if a half block between the guard bar and the right block is input.

For example, as shown in FIG. 5, when the time input as the scan lines S ₀ and S ₁ are made to be also read the left block, right block, which is input to the scanning line l ₀ or l ₁ Cannot be read.

[Problems to be solved by the invention]

As described above, the barcode configuration for reading the barcode is accurately determined. As described above, the left margin and the right margin outside the guard bar are prepared and printed in seven or more modules, for example, JIS bar. It is determined by the code printing standard.

However, depending on the maker, particularly in Europe and the like, there is a case where the left margin or the right margin is shorter than the length specified by the printing standard as shown in FIG.

When reading barcodes, if the check is made loose or not so that the white margin outside the guard bar may be short, there is a risk of misreading when demodulating by half blocks as in the conventional method .

For example, as shown in FIG. 7 (A), when it is checked that there are seven or more modules of the white margin, the bar code from the center bar (CB) to the guard bar (GB) is represented by an odd parity of 4 (shown as O4). Accurate demodulation is possible. However, if the check of the white margin is omitted, as shown in the lower part of FIG.
(Indicated as O0). Further, as shown in FIG. 7 (B), the even module 6 (indicated by E6) may be erroneously read as a guard bar (GB).

If the check is made loose so that the width of the white margin may be short, an erroneous reading may occur as indicated by E6 in FIG. 7B.

Accordingly, an object of the present invention is to provide a barcode demodulation method capable of accurately reading a barcode label having a short white margin on one side.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, a margin check unit 1, a guard bar check unit 2, a character configuration check unit 3, a center bar check unit 4, a demodulation unit 5, a sequence control unit 6, a demodulation unit A data storage unit 7 is provided.

Now, a barcode is read, and the obtained barcode data (white / black distinction and its width) is used as a margin check unit 1, a guard bar check unit 2, a character configuration check unit 3, a center bar check unit 4, a demodulation unit 5, and the like. To enter. The bar code, for example, as shown in beams B ₁ of FIG. 6, to the side which does not exist from sufficiently present the side of the white margin, when reading the bar code through manner, the first white at the margin check unit 1 to confirm the presence of the margin, it turns on the margin there flag F _0. Then, the guard bar checker 2 detects the guard bar GB,
The character configuration check unit 3 checks whether or not the subsequent barcode has a predetermined character configuration of seven modules in width and two white bars and two black bars. When the character configuration check unit 3 outputs a character configuration check OK signal, the sequence control unit 6 outputs a demodulation execution signal to the demodulation unit 5.
In this manner, the demodulated data of the left block is sequentially stored in the demodulated data storage unit 7 constituted by, for example, a shift register. At this time, the signal of odd parity or even parity is also stored.

When the center bar check unit 4 detects the center bar CB after, for example, six-digit demodulation, the sequence control unit 6 stores the six-digit demodulated data of the left block held in the demodulated data storage unit 7 into the control unit 8. To be held.

Then, similarly, the demodulated data of the right block is sequentially stored in the demodulated data storage unit 7, and after 6-digit demodulation, this is transmitted to the control unit 8
To be held. At this time, the control unit checks the same number of digits of the left and right blocks, and calculates the first digit of the left block by a combination of the odd parity and the even parity, and outputs 13-digit demodulated data.

Of course, like the beam B ₀ shown in FIG. 6, when read through to the bar code from a not sufficiently right white margin to the left in the presence of white margin, margin flag F for the beginning of the right 6-digit _By demodulating with ₀ turned off and temporarily notifying this to the control unit 8 and detecting the presence of a white margin after demodulating the left block, a completion notification is given, so that it is possible to read it accurately.

[Action]

In this way, the bar code can be read even when the white margin of the left or right one block is short.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a block diagram of one embodiment of the present invention, and FIG. 3 is an explanatory diagram of its operation.

In FIG. 2, the same reference numerals as those in FIG. 1 indicate the same parts, 9 is a reading unit for reading a bar code and converting it into an electric signal, and 10 is a bar width counter for measuring the bar width. Each of them is identified, the identification signal and the bar width are quantized, and a value indicating the width is output, whereby it is possible to determine the width of the white bar and the black bar.

The sequence control unit 6 has a margin presence flag F ₀ indicating that the presence of a white margin has been detected, a half block flag F ₁ indicating that half block data has been detected (four-digit flag F ₁₄ , six-digit flag F ₁₄₎ constituted by a flag F _16), it is provided completion flag F ₂ showing a completion-of-demodulation.

The control unit 8 has a digit number matching unit 11 for detecting whether or not the digit numbers of the demodulated data of the left block and the right block match, and concatenates the data of the left block and the right block. In the case of the version, there is provided a linking unit 12 for linking and outputting also the first digit calculated by the control unit 8 based on the odd / even parity of the left block.

Next, the operation of the present invention will be described with reference to FIG. 2 and FIG.

When reading a bar code, that is, at the start of demodulation, the control unit 8 instructs the sequence control unit 6 to send each flag.
Instructs to turn off all of F ₀ , F ₁ , and F ₂ . Thus, the sequence control unit 6 turns off the half-block flag F ₁ (four-digit flag F ₁₄ , six-digit flag F ₁₆ ), turns off the completion flag F _12, and also turns off the margin presence flag F _0. To

The binary signal output from the reading unit 9 is a bar width counter.
According to 10, the white width and the black width are counted. First, the guard bar check unit 2 detects the presence of a guard bar (GB) having a bar width of 1 module in a pattern of “1” (black bar), “0” (white bar), and “1”, and performs sequence control. When notified to the unit 6, the sequence control unit 6
Checks whether the margin check unit 1 has detected the white margin outside the GB as a margin of, for example, 7 modules or more by that time. The margin to turn the margin presence flag F ₀ if (Sixth
State of the beams B ₁ in the figure).

'However, as in the beam B ₀ of FIG. 6, if no margin Margin - present flag F ₀ is not turned on.

Then, the character configuration checking unit 3 decodes the signal output from the bar width counter 10
When one character having two modules and two black bars and a total module width of 7 modules is detected, a check signal indicating that the character configuration is good is output. As a result, the sequence control unit 6 outputs a demodulation instruction signal to the demodulation unit 5, so that the demodulation unit 5 displays a character having two white bars and two black bars, each having a total module width of 7 modules. Decrypt and demodulate to specific numbers. At this time, it is also decoded whether this character is odd parity O or even parity E. These are sequentially stored in the demodulation data storage unit 7.

The sequence control unit 6 has a built-in counter, and is incremented by 1 based on the output of the check signal from the character configuration check unit 3. Then, when the 4-digit demodulation is completed, if the center bar check unit 4 detects the center bar (CB) next, a detection signal is received and the sequence control unit 6 confirms that the half block of the half block flag has a 4-digit configuration. Turn on F ₁₄ shown.

However, if the center bar is not detected, two more
When six digits are demodulated, the presence or absence of a CB is monitored. If the center bar check unit 4 detects the CB, the sequence control unit 6 sets a half block flag F ₁₆ indicating that the half block has a six digit configuration. Turn on.

In this way, if the margin presence flag F ₀ in the case where demodulation is performed half a block is turned on, the sequence control unit 6 outputs a demodulation completion notice to the control unit 8, also turned on If not, a provisional notification of demodulation completion is output.

After the half-block demodulation, when the sequence control unit 6 subsequently outputs a check signal indicating that the character configuration is good from the character configuration check unit 3,
The demodulation unit 5 outputs a demodulation instruction signal to the demodulation unit 5. As a result, the demodulated data (including odd and even parities) output from the demodulation unit 5 is sequentially stored in the demodulation data storage unit 7.

When the 4-digit demodulation is completed, the sequence control unit 6
If applied GB detection signal from the guard bar check unit 2 are already checked whether the half-block flag F ₁₄ is on for 4-digit, followed if ON margin chromatic signal from the margin check unit 1 is output When this is done, a demodulation completion notification is made. If F ₁₄ is on, the flag with margin F ₀
Is turned on or off, and if it is on, a demodulation completion notification is made. However to check the completion flag F ₂ when the margin signal present from the margin check unit 1 if OFF is outputted,
Although the demodulation completion notification is performed, if the margin presence signal is not output, demodulation control is subsequently performed according to the check signal from the character configuration check unit 3.

Thus six digits when demodulated, the sequence control unit 6 if it is transmitted is GB detection signal from the guard bar checking section 2 checks whether the half-block flag F ₁₆ for 6-digit is on, turned on long as it margin presence flag F ₀ outputs a demodulation completion notice if oN, turns on the completion flag F ₂ when the margin presence flag F ₀ margin chromatic signal is output from a margin check unit 1 to be turned on And outputs a demodulation completion notification. Half block flag F
_{If 16} is not turned on, a demodulation completion notification is made when a margin signal is output.

In this manner, the scanning direction of the beam, even if the not sufficiently direction white margin on the outside of the guard bar as the B ₀ of FIG. 6, sufficiently white margin on the outside of the guard bar as B ₁ Even in the direction from which the bar code exists, if one of the bar codes has a white margin and the bar code is continuously scanned in the order of GB → CB → GB, the bar code can be accurately read.

The control unit 8 determines whether the data obtained from the demodulated data storage unit 7 is correct, for example, whether the number of digits of one half block matches the number of digits of the other half block. The number matching unit 11 checks whether or not the state of odd parity and even parity is correct. If correct, the half blocks are connected by the connection unit 12 at a time, and the half block has six digits each. In the standard version, the first digit is created from the odd and even parity states of the left block as is well known. Then, the correctness of these demodulated data is checked by the modular check character, and if it is correct, this is output.

〔The invention's effect〕

In the present invention, in a bar code, outside the white margin GB exists only one of the left or right, even when the insufficiently other white margin, beam B ₀ or B ₁ shown in FIG. 6
This bar code can be accurately read when these are read continuously as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a block diagram illustrating an embodiment of the present invention, FIG. 3 is a diagram illustrating the operation of the present invention, FIG. 4 is a diagram illustrating a barcode, FIG. FIG. 6 is a diagram for explaining a bar code in which one side block has an insufficient white margin, and FIG. 7 is a diagram for explaining a bar code erroneous reading when the white margin is insufficient. 1 Margin check unit 2 Guard bar check unit 3 Character configuration check unit 4 Center bar check unit 5 Demodulation unit 6 Sequence control unit 7 Demodulation data storage unit

Claims (1)

(57) [Claims] 1. A bar code reading device provided with guard bars on both sides thereof and reading a bar code having a white margin set outside the guard bar, a margin check means for detecting a white margin of the bar code; Guard bar checking means for detecting a guard bar, character configuration checking means for detecting that the character configuration of the barcode is correct, and demodulation means for demodulating the barcode, when the barcode is read, A bar code reader, wherein a bar code can be demodulated when the margin check means detects that a white margin of a specified length exists outside at least one of the guard bars.