JPH05233866A - Bar code demodulator - Google Patents

Abstract

PURPOSE:To provide the bar code demodulator for surely demodulating an add-on bar code even when a symbol is scanned from the right side concerning the bar code demodulator for demodulating the add-on bar code expressed by the add-on bar code symbol from the read output of this symbol. CONSTITUTION:This device is provided with a character length estimating means 11, a first width detecting means 12 and a module number calculating means 13 for demodulation and a character demodulating means 14 and based on the estimated length of a character and the detected width of a block excluding a module number calculating block for demodulation, which one terminal part is coincident with one terminal part of this character, from the character, the number of modules in the module number calculating block for demodulation is calculated. By using this calculated result, the character is demodulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code demodulating device for demodulating an add-on bar code represented by this add-on bar code symbol from a read output.

In recent years, in an information management system using a bar code, a combination of two bar codes having different code systems may be used as a bar code with the diversification of management information.

When using such a bar code,
A bar code demodulating device capable of demodulating any of the two bar codes is required.

[0004]

2. Description of the Related Art A bar code with an add-on bar code is a bar code that combines two bar codes having different code systems.

FIG. 5 shows a UPC system bar code (UPC / A, EAN8, EAN1) having a right block and a left block.
It is a figure which shows the symbol structure of the barcode with an add-on barcode which makes 3) the main barcode.

The main bar code symbol MBS includes a left margin portion LM, a left guard bar LGB, a left character portion LC, a center bar CB, a right character portion RC, a right guard bar RGB, and a right margin portion RM.
It is composed of 1.

The add-on bar code symbol ABS is composed of a special left guard bar SLGB, an add-on character portion AC, and a right margin portion RM2.

The left guard bar LGB is provided to determine whether the read output is the read output of the bar code symbol. Also, this left side guard bar LGB is
It is located at the left end of the left character portion LC and also has a function of separating it from the left margin portion LM.

Although not described in detail, the other guard bars RGB and SLGB also have the same function as the left guard bar LGB.

The center bar CB has a left character portion LC.
It is a partition located at the right end portion of the partition for distinguishing it from the right character portion RC.

The add-on bar code symbol ABS
Does not have a left margin part because the right margin part RM1 of the main bar code symbol MBS fulfills the function of this left margin part.

FIG. 6 is a diagram showing a symbol structure of a bar code with an add-on bar code having a UPC bar code (UPC / E) having only one block as a main bar code.

The structure in this case is that there is one block of the main bar code symbol MBS, and for this reason,
Except that there is no center bar CB, the configuration is almost the same as in the case of having two blocks.

When demodulating the add-on bar code as described above, the number of modules is calculated for each of a plurality of predetermined sections, as in the case of demodulating the main bar code. Hereinafter, this section is referred to as a demodulation module number calculation section. The number of modules in each demodulation module number calculation section is obtained from the detection width of this section and the detection length of the character.

However, in such a configuration, when the add-on barcode symbol ABS is scanned from the right side, it may not be possible to demodulate the add-on barcode.

That is, when scanning a bar code symbol, the detection width of the black bar that is scanned first may be apparently large. The reason for this is that the amplitude level of the symbol read output changes due to dust or the like on the margin.

Even if such a situation occurs, there is no problem if the first black bar scanned is that of the guard bar. This is because in the case of the guard bar, the relative position of the two black bars is more important than the detection width of the black bar.

On the other hand, in the case of a character, demodulation is performed based on the detection width of the demodulation module number calculation section and the detection length of the character. Therefore, if the detection width of the bar changes, these also change and the demodulation is not successful. There are cases where it becomes possible.

This will be described with reference to FIGS. 7 and 8.
FIG. 7 is a diagram showing a symbol scanning direction. In the figure, shows the case where the symbol is scanned from the left side,
Indicates the case of scanning from the right side. FIG. 8A shows
8B shows the read output of the symbol in the case of FIG.
Indicates the read output in the case of.

In the case of FIG. 8, as shown in FIG. 8A, the black bar RB at the right end portion of the add-on character portion AC does not become thick. On the other hand, in the case of, as shown in FIG. 8B, the black bar RB may become thick.

As a result, the detection width and the character detection length of the demodulation module number calculation section including the black bar RB are increased. As a result, the number of modules in the demodulation module number calculation section including the black bar RB deviates from the original value, and the character including the black bar RB cannot be demodulated.

In particular, when the stationary reading device is used as the reading device for the bar code symbol, the scanning with and the scanning are performed alternately, and therefore the above-mentioned problems are likely to occur.

[0023]

As described above, the conventional add-on bar code demodulating device has a problem that demodulation may not be possible when the symbol is scanned from the right side.

Therefore, an object of the present invention is to provide a bar code demodulating device which can surely demodulate an add-on bar code even when a symbol is scanned from the right side.

[0025]

FIG. 1 is a block diagram showing the configuration of the invention according to claim 1. As shown in FIG.

In the figure, 11 is a character length estimating means for estimating the length of the character based on the read output of the bar code symbol. Reference numeral 12 is a width detecting means for detecting a width of a section excluding the demodulation module number calculation section in which one end of the character matches the one end of the character.

Reference numeral 13 is a demodulation module number calculation means for calculating the number of modules in the demodulation module number calculation section based on the estimation result of the character length estimation means 11 and the detection result of the width detection means 12.

Reference numeral 14 is a character demodulation means (14) for demodulating the character, with the calculation result of the demodulation module number calculation means 13 as the number of modules in the demodulation module number calculation section.

[0029]

In the above structure, the number of modules in the demodulation module number calculation section is calculated based on the detection width of sections other than this section and the estimated length of the character.

Therefore, even if the detection width of the demodulation module number calculation section or the detection length of the character changes apparently,
Accordingly, the number of calculation modules does not change. As a result, even if the add-on barcode symbol is scanned to the right, the character at the right end can be reliably demodulated.

[0031]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is a block diagram showing the configuration of a bar code reading device equipped with a bar code demodulating device according to an embodiment of the present invention.

Before describing the configuration and operation of FIG. 2, here will be described a conventional demodulation processing mode (hereinafter referred to as “first demodulation processing mode”) and this embodiment with reference to FIG. The demodulation processing mode (hereinafter, referred to as “second demodulation processing mode”) will be described.

First, the first demodulation processing mode will be described.
FIG. 4 is a diagram showing the read outputs of the first character C1 and the second character C2 from the right of the add-on character portion AC.

As shown in the figure, in the case of an add-on bar code,
Each of the characters C1 and C2 is composed of four bars. The color of each bar is set from the left to white → black → white → black. Hereafter, these bars will be
1, B1, W2 and B2.

The characters C1 and C2 are separated by a bar called a delineator (D). The delineator (D) is composed of a pair of white and black bars having the same width.

The number of modules of each character C1 and C2 is set to 7 modules. These 7 modules are
Contents of characters C1 and C2 (“0”, “1”,
According to "2", ...), four bars W1, B1, W2
It is appropriately assigned to B2.

Therefore, if the demodulation module number calculation section is set for each bar W1, B1, W2, B2, the characters C1, C2 can be demodulated.

However, in general, the demodulation module number calculation section is not set in bar units, but is set in edge, two, or edge units in which white bars and black bars are combined. This is to avoid the influence of the printing error of the symbol as much as possible.

Generally, the section for calculating the number of demodulation modules in units of edge, two, and edge is the section from the rising edge of the black bar B1 to the rising edge of the black bar B2, and the falling edge of the black bar B1 to the black bar B2. The interval to the falling edge of is used.

The module numbers M1 and M2 in both demodulation module number calculation sections are obtained based on the following equations (1) and (2), respectively.

M1 = (T1 / Lc) × 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (1) M2 = (T2 / Lc) × 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (2 )

Here, T1 and T2 are detection widths of each demodulation module number calculation section, and are usually called delta distances. Lc is the detected length of the character. These delta distances T1 and T2 and the character detection length Lc are detected from the read output of the symbol.

The number M of modules thus obtained
The array of M1 and M2 (M1, M2) is collated with a regular array registered in the table in advance for each character, for example. As a result, the character is demodulated.

The characters "1" and "7" and "2" and "8" cannot be distinguished only by calculating the number of modules M1 and M2. So, in fact,
The above distinction is made by calculating the number of modules of any one bar, for example, the white bar W1.

The above is the contents of the demodulation processing in the first demodulation processing mode. Next, the second demodulation processing mode will be described.

If the symbol is scanned from the right side (see FIG.
In this case), in the character C1, the bar located at the right end, that is, the black bar B2, becomes thicker as shown by the broken line in FIG.

As a result, the character detection length Lc and the delta distance T2 become larger than their original values. As a result, the module number M2 calculated in the first demodulation processing mode deviates from the original module number, and the character C1
Cannot be demodulated.

Therefore, in the second demodulation processing mode, the number of modules M2 is set to the detection length Lc of the character C1.
And the character C, not from Delta Distance T2
This is obtained from the estimated length of 1 and the delta distance T3.

Here, the delta distance T3 is the detection width of the section from the falling edge of the black bar of the delineator (D) to the falling edge of the black bar B1. In other words, it is the detection width of a section excluding the demodulation module number detection section corresponding to the delta distance T2 from the character.

The demodulation module number detection section corresponding to the delta distance T2 is a section including the black bar B2. In other words, the right end is a section where the right end matches the right end of the character C1.

The demodulation process in the first demodulation process mode described above basically comprises the following five processes.

(1) Based on the read output of the symbol,
A process of estimating the length of the character C1. (2) A process of detecting the delta distance T3 from the read output of the symbol. (3) Estimated length of character C1 and delta distance T
3 and the number M3 of modules in the section corresponding to this T3
The process of calculating.

(4) A process of subtracting M3 from the number of modules of the character C1. (5) The number of modules obtained by this subtraction is used as the number of modules M2 in the section corresponding to the delta distance T2, and using this and the number of modules M1, the character C
The process of demodulating 1.

As an estimation method of (1), for example, the length Lc of the clutter C1 is set to the character C immediately adjacent to it.
A method of substituting a length Lc of 2 is used.

The above is the contents of the demodulation processing in the second demodulation processing mode. Next, with reference to FIG. 2, the configuration and operation of the entire bar code reader having the demodulation function as described above will be described.

In FIG. 2, the laser beam emitted from the laser beam emitting unit 21 is deflected by the beam deflecting unit 22 and is applied to the label on which the bar code symbol is printed. Thereby, the barcode symbol is scanned by the laser beam.

In this scanning, the laser beam reflected from the label is received by the beam receiving section 23 and then converted into an electric signal. The waveform of the converted output is shaped by the waveform shaping unit 24.

This waveform shaping output is supplied to the bar width detecting section 25 and used for detecting the bar width. The width data of each bar obtained by this detection processing is sequentially supplied to the barcode detection unit 26 and stored in the data buffer 27.

In the bar code detector 26, a process of detecting a bar code from the input data and outputting various pointer signals necessary for demodulating the bar code is executed.
The width data stored in the data buffer 27 is based on this pointer signal, and the central processing unit (hereinafter, “CPU”)
28).

The demodulated output is stored in a random access memory (hereinafter referred to as “RAM”) 29, and then transferred to a host computer (not shown) via the interface section 30.

The operations of the laser beam emitting section 21 and the beam deflecting section 22 are controlled by the control section 3 under the control of the CPU 28.
Controlled by 1.

Various control programs for the CPU 28 are stored in a read-only memory (hereinafter referred to as "ROM") 32.

FIG. 3 is a flow chart showing the contents of the demodulation control program stored in the ROM 32. Here, the demodulation processing by the CPU 28 will be described with reference to FIG.

In this process, first, a main bar code demodulating process is executed (step S1). next,
If necessary, add-on barcode demodulation processing is executed (steps S2 to S6, S13 to S17). Finally,
The demodulation result inspection process is executed (steps S7 to S1).
2, S18-S20).

The demodulation of the main bar code is performed by the first method described above.
The demodulation processing mode is executed. This demodulation result is
It is stored in the demodulation area of the RAM 29.

When this storing process is completed, a process for determining whether or not an add-on flag indicating a request for demodulating an add-on bar code is set is executed (step S2). Whether or not this add-on flag is set is determined by the operator.

When the determination result that the add-on flag is set is obtained, a process for determining whether the parity of the right character part RC is an odd parity is executed (step S3). By this determination process, the main barcode is
It is determined whether the barcode is a UPC-based barcode having two blocks as described with reference to FIG.

When the determination result that the parity is odd is obtained, a process for determining the scanning direction of the bar code symbol is then executed (step S4).

When the determination result that the scanning is performed from the left side is obtained by this determination process, the demodulation process of the add-on bar code is executed based on the first demodulation mode (step S5). The demodulation result is stored in the demodulation area of the RAM 19.

Upon completion of this demodulation process, a process of setting an add-on flag indicating that the demodulation process of the add-on barcode has been executed is executed (step S6).

When this process ends, a process for determining whether the add-on process flag is set is executed (S).
7). When the determination result that the add-on flag is set is obtained, the process of storing the demodulated output of each bar code in the inspection area of the RAM 29 is executed (step S).
8).

When this storing process is completed, a process for checking whether the demodulated output of each bar code is normal is executed (steps S9 to S12). If it is determined by this processing that the output is normal, the process proceeds to a transfer processing routine that transfers the demodulated output to the host computer. On the other hand, if it is determined that the error is not normal, there is a possibility that a reading error or the like has occurred, so the process proceeds to an error processing routine for coping with these.

When the determination result that the scanning is performed from the right side is obtained in step S4, first, the process of determining whether or not the character to be demodulated is the character C1 located at the right end portion is executed (step S13). ..

When a result of the determination that the character C1 is the character C1 is obtained by this determination process, a process of determining whether or not the detection width XB2 of the black bar B2 of the character C1 is larger than a predetermined width is executed (step). S14). Here, the predetermined width is set to be 6 times the detection length Ld of the delineator D.

By this determination processing, the detection width XB2 is 6L.
If it is determined that it is larger than d, the demodulation processing in the second demodulation processing mode is executed (step S15). The demodulation result is stored in the demodulation area of the RAM 19.

After this, the determination process of step S13 is executed again. In this determination process, since the demodulation of C1 has been completed, the process proceeds to step S5.

As a result, the demodulation processing in the second demodulation processing mode is executed only for the character C1, and the demodulation processing in the first demodulation processing mode is executed for the other characters.

In step S14, the detection width XB
When the determination result that 2 is not larger than 6Ld is obtained, the process proceeds to the error processing routine. This is because if the symbol is scanned from the right side, it is highly possible that the determination condition of step S14 is satisfied, but the fact that this condition is not satisfied means that a reading error or the like may have occurred. Because it is expensive.

When it is determined in step S3 that the parity of the right-side character portion RC is not odd parity, a process of determining whether the main bar code is a UPC / E code is executed (step S16).

When the determination result that the code is the UPC / E code is obtained by this determination processing, since the add-on barcode is added in this case as well, the demodulation processing according to the scanning direction is executed (step S4). S5, S13 ~ S
15).

On the other hand, when the determination result is not the UPC / E code, the add-on barcode is not added, so that it is not necessary to execute the demodulation processing of the add-on barcode. Thus, in this case, step S
The inspection process of the bar code demodulated in 1 is executed (steps S18, S19, S20). This is step S
The same applies to the case where the determination result that the add-on flag is not set in 2 is obtained.

According to this embodiment described in detail above, the following effects can be obtained.

(1) Since the module number M2 is calculated based on the estimated length of the character C1 and the delta distance T3, the character C1 can be surely demodulated even when the symbol is scanned from the right side. it can.

(2) Further, as the method of estimating the length of the character C1, the method of substituting this for the detection length Lc of the character C2 immediately adjacent thereto is used, so that the reliability of the estimated length can be improved.

(3) Further, a scanning direction determination function is provided,
When the symbol is scanned from the left side, the demodulation processing in the first demodulation processing mode is executed, so that it is possible to prevent the demodulation processing speed from decreasing in this case.

(4) Further, a bar width determination function is provided, and when the detection width XB2 of the black bar B2 is smaller than the predetermined width,
Since the process shifts to the error processing routine, it is possible to avoid the inconvenience that the demodulation process is executed even if a reading error or the like has occurred.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to such an embodiment.

(1) For example, in the above embodiment, the case where the length of the character C1 is substituted by the detection length Lc of the character C2 has been described. However, in addition to this, for example, the detection length of the delineator (D) It is also possible to substitute Ld by 3.5.

(2) In the previous embodiment, as a method of calculating the module M2, first, the number of modules M3 is obtained, and then M2 is obtained by subtracting this M3 from the number of modules of the character C1. explained.

However, in the present invention, first, the character C
Alternatively, the delta distance T2 may be obtained from the estimated length of 1 and the delta distance T3, and the module number M2 may be obtained from the estimated length of the delta distance T2 and the character C1.

(3) In the above embodiment, the case where the demodulation processing of the second demodulation processing mode is executed only when the scanning is performed from the right side has been described. The demodulation process may be executed.

(4) In the above embodiment, the case where the demodulation processing in the second demodulation processing mode is executed only for the character C1 has been described, but this demodulation processing is performed for the entire add-on character section AC. It may be executed.

(5) The case where the present invention is applied to a bar code demodulating device which sets the demodulation module number calculation section in units of edge, two, and edge has been described. It is also applicable to such devices.

(6) Further, although the case where the present invention is applied to demodulation of an add-on bar code has been described in the above embodiment, the present invention can also be applied to demodulation of other bar codes.

In this case, like an add-on bar code,
It can be applied not only to a bar code having no guard bar only at one end but also to demodulation of a bar code having no guard bar at both ends. Further, it can be applied not only to demodulation of a bar code having no guard bar, but also to demodulation of a bar code having a guard bar.

(7) In addition to this, it goes without saying that the present invention can be variously modified without departing from the scope of the invention.

[0097]

As described in detail above, according to the present invention,
Even when the add-on barcode symbol is scanned from the right side, it is possible to provide the barcode demodulating device that can surely demodulate the character at the right end portion.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an invention according to claim 1.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 3 is a flowchart showing a demodulation process of an embodiment of the present invention.

FIG. 4 is a diagram for explaining an outline of demodulation processing according to an embodiment of the present invention.

[Fig. 5] UPC / A to which an add-on barcode is added,
It is a figure which shows the symbol structure of EAN8 and EAN13 code.

FIG. 6 is a diagram showing a symbol structure of a UPC / E barcode to which an add-on barcode is added.

FIG. 7 is a diagram showing a symbol scanning direction.

FIG. 8 is a signal waveform diagram for explaining a conventional problem.

[Explanation of symbols]

11 Character Length Estimating Means 12 First Width Detecting Means 13 Demodulation Module Number Calculating Means 14 Character Demodulating Means

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuo Watanabe 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (9)

[Claims] 1. From the read output of the bar code symbol,
In a bar code demodulating device for demodulating a bar code represented by this symbol, based on the read output of the bar code symbol, a character length estimating means (11) for estimating the length of the character, and one end from the character is Width detection means (12) for detecting the width of the section excluding the demodulation module number calculation section that coincides with one end of this character, the estimation result of the character length estimation means (11) and the width detection means (12) The demodulation module number calculation means (13) for calculating the number of modules in the demodulation module number calculation section, and the calculation result of the demodulation module number calculation means (13) As the number of modules in the module number calculation section,
A bar code demodulating device comprising a character demodulating means (14) for demodulating the character. 2. The demodulation module number calculation means (13)
Is a first module number calculation means for calculating the number of modules in the section based on the estimation result of the character length estimation means (11) and the detection result of the width detection means (12); The bar code demodulating device according to claim 1, further comprising a second module number calculating unit that calculates the number of modules in the demodulation module number calculating section based on the calculation result of the module number calculating unit. 3. The demodulation module number calculation means (13)
Is a width calculation means for calculating the width of the demodulation module number calculation section based on the estimation result of the character length estimation means (11) and the detection result of the width detection means (12), and the character length estimation 2. A module number calculation means for calculating the number of modules in the demodulation module number calculation section based on the estimation result of the means (11) and the calculation result of the width calculation means. Bar code demodulator. 4. The character demodulation means (1) only when the width of the demodulation module number calculation section detected from the read output of the bar code symbol is larger than a predetermined width.
The bar code demodulating device according to claim 1, further comprising a first demodulating process control means for controlling the demodulating process so that the demodulating process according to 4) is executed. 5. The bar code demodulating device according to claim 1, wherein the bar code symbol is configured so as not to have a guard bar between the character part and the margin part. 6. The demodulation process is controlled so that the demodulation process by the character demodulation means (14) is executed only when the character is a character that is in contact with the margin portion without passing through the guard bar. 6. The bar code demodulating device according to claim 5, further comprising: 2 demodulation processing control means. 7. The bar code demodulator according to claim 5, wherein the bar code symbol is configured not to have the guard bar only at one end of the character part. 8. A third demodulator controlling the demodulating process so that the demodulating process by the character demodulating means (14) is executed only when the bar code symbol is scanned from one end side of the character part. 6. The bar code demodulating device according to claim 5, further comprising demodulation processing control means. 9. The bar code demodulator according to claim 5, wherein the bar code is an add-on bar code.