JP2002352185A - Barcode reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a barcode decoder by which a barcode can speedily and precisely decoded using a simple constitution. SOLUTION: A barcode reader 10 generates a scanning beam L1 by a scanning mechanism 12 from an optical beam emitted from a light source, scans a barcode label 14 with this scanning beam, photodetects its reflected light with a photodetecting part 15, converts an analog signal from the photodetection part to a binary digital signal, decodes the barcode with a decoder 17 and outputs the result of decoding to an external device with an outputting device 19. The scanning mechanism generates the patterns of a plurality of scanning beams L1a and L1b, and a comparison and discrimination device 18 compares the decoding results of the barcodes obtained by the pattern of the beams L1a and L1b, to output the decoding results to the output device, only when the decoding results coincide with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader, and more particularly to a technique for reading a bar code in a bar code reader.

[0002]

2. Description of the Related Art Conventionally, a bar code reader is configured as shown in FIG. In FIG. 3, a bar code reader 100 includes a light source 110, a high-speed rotating polygon mirror 120 as a scanning mechanism for scanning light from the light source 110, and a bar code label 1 to be read.
A light receiving unit 140 that receives the reflected light from the light receiving unit 30;
An AD converter 150 that converts the detection signal from the A / D converter 40 into a digital signal, a decoder 160 that decodes a barcode based on the digital signal from the AD converter 150, and a decoding result that is decoded by the decoder 160. And an output device 170 for outputting the data to

The light source 110 is composed of, for example, a laser oscillator or the like, and emits a light beam such as a laser beam having a predetermined wavelength. The high-speed rotating polygon mirror 120 is composed of mirrors attached to each surface of the polyhedron. The high-speed rotating polygon mirror 120 is rotated at a high speed by a driving unit (not shown) to reflect a light beam from the light source 110 and convert the scanning beam L1. Is to be generated.

[0004] The light receiving section 140 receives the scanning beam L1.
Is a bar code label affixed to the surface of, for example, luggage
Scanning over the bar code label 13
The reflected light L2 reflected by the barcode label 130 is received to detect a level change of the reflected light L2 due to the barcode 131 on the barcode label 130, that is, to output an analog signal based on the level of the reflected light L2. Has become.

Here, in the case shown in the figure, the bar code label 1
The reflected light L2 from 30 is again reflected toward the light source 110 by the high-speed rotating polygon mirror 120, and is reflected by the perforated mirror 180 as a light branching unit, so as to be incident on the light receiving unit 140. I have. In this case, the light beam from the light source 110 is
It passes through 80 holes.

When the analog signal from the light receiving unit 140 is equal to or larger than a predetermined threshold, the AD converter 150
By outputting an H-level signal and outputting an L-level signal when the signal is less than the threshold value, an H-level signal is generated for the reflected light L2 from the white bar portion of the barcode 131 on the barcode label 130. And outputs an L-level signal for the reflected light L2 due to the black bar portion.

The decoder 160 decodes a bar code 131 on a bar code label 130 from a series of digital signals obtained by scanning the scanning beam L1 based on the digital signal from the AD converter 150, and decodes the result. Is output. The output unit 170 outputs the decoding result decoded by the decoding unit 160 to an external device (not shown).

[0008] The bar code reader 10 having the above-described structure is used.
According to 0, a light beam from a light source 110 passes through a perforated mirror 180, is reflected by a high-speed rotating polygon mirror 120, and is scanned with a scanning beam L1 scanned on a barcode 131 on a barcode label 130. Become.

When the scanning beam L1 scans the barcode 131 on the barcode label 130, the light L2 reflected by the barcode 131 is reflected again by the high-speed rotating polygon mirror 120 and returns toward the light source 110. , Reflected by the perforated mirror 180,
It is incident on 40.

Thus, the light receiving section 140 detects the reflected light L2, outputs an analog signal, and outputs the analog signal.
50 is a bar code 13 based on the analog signal.
A binary digital signal corresponding to the white bar portion and the black bar portion is output. Then, the decoder 160 decodes the barcode based on the binary digital signal from the AD converter 150, and outputs the decoding result to the output unit 170.
Is output to an external device via the.

[0011]

The light L2 reflected by the bar code 131 on the bar code label 130 is used.
The reflection level fluctuates based on the material of the barcode label 130, the reflection characteristics of the barcode printing, and the like.

For this reason, depending on the incidence condition of the scanning beam L1 on the bar code label 130, the light receiving section 140
, The level of the reflected light L2 in the white bar portion and the level of the reflected light L2 in the black bar portion cannot be determined based on the predetermined threshold value. As a result, the bar code 131 cannot be read accurately, and the decryption device 160 performs an incorrect decryption, and the erroneous decryption result is output to the external device via the output device 170. was there.

In order to prevent such erroneous reading of a bar code, for example, Japanese Unexamined Utility Model Publication No. Hei.
Various methods are disclosed in Japanese Patent Application Laid-Open No. 1-26185 and Japanese Patent Application Laid-Open No. 64-36382. 2-23
In the bar code scanning method disclosed in Japanese Patent No. 764, a light beam is scanned over a plurality of paths on a bar code label, and the head pattern of the digital read signal in each scanning path is compared. However, in this case, since only a part of the digital read signal is compared, there is a problem that accuracy is low.

In the bar code scanning method disclosed in Japanese Patent Application Laid-Open No. 61-26185, a plurality of read data are determined as one data by majority logic for each bar portion of the bar code. However, in this case, at least three or more barcode reading operations are required, and the determination operation is also complicated,
Barcode decoding takes time.

Further, in the bar code reader disclosed in Japanese Patent Application Laid-Open No. 64-36382, image data of the entire bar code is fetched into a memory, and a bar code read signal is obtained from the image data through a plurality of paths. However, in this case, since the image data must be processed, the processed data becomes enormous, and it takes time to decode the barcode.

On the other hand, in order to prevent erroneous reading of a bar code, for example, there is a method of using a plurality of bar code reading devices. It is necessary to compare the bar code decoding results.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and provides a barcode decoding apparatus capable of quickly and accurately decoding a barcode with a simple configuration. With the goal.

[0018]

In order to achieve this object, a bar code reader according to a first aspect of the present invention generates a scanning beam from a light beam emitted from a light source by a scanning mechanism, and generates the scanning beam. The beam is scanned on the bar code label, the reflected light is received by the light receiving unit, the analog signal from the light receiving unit is converted to a binary digital signal, and the bar code is decoded by the decoder, and the decoding result is obtained. A bar code reader, wherein the scanning mechanism is configured to generate a plurality of scanning beam patterns, and the bar is obtained by each of the scanning beam patterns. It is configured to include a comparison / determination unit that compares the decoding results of the codes and outputs the decoding result to the output unit only when the decoding results match.

When the bar code reading apparatus has such a configuration, a plurality of scanning beam patterns are generated by the scanning mechanism, and the bar code is read by each scanning beam pattern, thereby decoding the bar code. The decoding result for each scanning beam pattern is compared by a comparison / determination unit, and only when the decoding results match, the decoding result is output to an external device via an output unit.

Thus, a bar code can be read with a plurality of scanning beam patterns by one bar code reading device without using a plurality of bar code reading devices as in the prior art. Each decoding result is compared by a comparison / determination unit, and only a correct decoding result is output to an external device via an output unit. If the decryption results do not match due to the comparison of the decryption results by the comparison / determination device, each decryption result is discarded and the barcode is read again, so that an incorrect decryption result is output to the external device. There is nothing.

According to a second aspect of the present invention, the bar code reader includes a scanning beam detector for detecting each of the scanning beam patterns, and the comparison / determination unit determines a bar code based on a detection result of the scanning beam detector. Is configured to compare the decoding results. The bar code reader according to claim 3 is
The scanning beam detector is a counter, and outputs a count value that is incremented each time a scanning beam pattern is detected, and the comparison / determination unit performs decoding based on the count value from the scanning beam detector. In this configuration, a count value is assigned to the decryption result from, and the decryption result of the barcode is compared.

When the bar code reader has such a configuration, the comparison / determination unit determines the decoding result from the decryption unit.
By associating with the detection result from the scanning beam detector, that is, the count value, the decoding result of the barcode can be grasped and compared for each scanning beam pattern.

According to a fourth aspect of the present invention, in the bar code reader, the scanning mechanism is a high-speed rotating polygon mirror. With this configuration of the barcode reader, a scanning beam can be easily obtained by rotating the high-speed rotating polygon mirror at high speed.

According to a fifth aspect of the present invention, there is provided a bar code reading apparatus including a light branching means for branching reflected light from a bar code label toward a light source via a high-speed rotating polygon mirror. According to a sixth aspect of the present invention, the light branching means is a perforated mirror.

When the bar code reading device is configured as described above, the reflected light from the bar code label is transmitted from the optical path of the scanning beam scanned from the light source via the high-speed rotating polygon mirror by the light branching means such as a perforated mirror. It can be easily branched.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of a barcode reader according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating the configuration of the barcode reading device according to the present embodiment.

As shown in FIG. 1, a bar code reader 1
0 indicates a light source 11, a high-speed rotating polygon mirror 12 as a scanning mechanism for scanning light from the light source 11, a scanning beam detector 13 for detecting a scanning beam from the high-speed rotating polygon mirror 12, and a reading target. A light receiving unit 15 for receiving light reflected from the bar code label 14;
The AD converter 16 that converts the detection signal from the AD converter 5 into a digital signal, the decoder 17 that decodes a bar code based on the digital signal from the AD converter 16, and the decoding result decoded by the decoder 17 are compared. And an output unit 19 for outputting the decoding result from the comparison / determination unit 18 to the outside
And is composed of

The light source 11 comprises, for example, a laser oscillator or the like, and emits a light beam such as a laser beam having a predetermined wavelength.

The high-speed rotating polygon mirror 12 is composed of mirrors attached to each surface of a polyhedron.
By being rotated at high speed by a driving means (not shown),
The light beam from the light source 11 is reflected to form the scanning beam L1.
Is generated. Here, in this case, the high-speed rotating polygon mirror 12 alternately generates a double scanning beam L1a, L1b pattern as a scanning beam pattern.

The scanning beam detector 13 is provided in a region where the scanning beam L1 is emitted from a scanning window 10a provided in the main body of the bar code reader 10 to the outside, and detects each scanning beam pattern of the scanning beam L1. It is designed to detect. That is, the scanning beam detector 13 is
Specifically, it is configured as a counter, and outputs a count value that is incremented each time the scanning beam L1 (L1a, L1b) is detected.

The light receiving section 15 is provided with a bar code label 14 on which the scanning beam L1 is attached, for example, on the surface of a load or the like.
By scanning above, the reflected light L2 reflected by the barcode label 14 is received, and the level fluctuation of the reflected light L2 due to the barcode 14a on the barcode label 14 is detected. An analog signal is output based on the level.

Here, in the case shown, the bar code label 1
4 is reflected again by the high-speed rotating polygon mirror 1
2, the light is reflected toward the light source 11 and is reflected by the perforated mirror 20 as a light branching unit, so that the light enters the light receiving unit 15. In this case, the light beam from the light source 11 passes through the hole of the perforated mirror 20.

The AD converter 16 converts an analog signal from the light receiving section 15 into a binary digital signal. That is, when the analog signal from the light receiving unit 15 is equal to or more than the predetermined threshold,
By outputting an H-level signal, and outputting an L-level signal when the value is less than the threshold value, an H-level signal is generated for the reflected light L2 from the white bar portion of the barcode 14a on the barcode label 14. And outputs an L-level signal for the reflected light L2 due to the black bar portion.

Based on the digital signal from the AD converter 16, the decoder 17 converts the bar code label 1 from a series of digital signals obtained by scanning the scanning beam L 1.
4 to decode the bar code 14a and output the decoding result.

The comparison / determination unit 18 compares the decoding results from the decoding unit 17 obtained from the respective scanning beam patterns based on the detection results of the scanning beam detector 13, and when these decoding results match, Only the decryption result is output to the output device 19. That is, the comparison / determination unit 18 converts the detection signal from the scanning beam detector 13 into the scanning beam L1.
a is detected, an even count value is detected when the scanning beam L1b is detected, and an odd count value is detected when the scanning beam L1b is detected. Based on these count values, the decoding result corresponding to the reflected light L2a from the decoder 17 and the reflected light L2b A count value is assigned to the decoding result to be compared, and the decoding results of the two barcodes are compared.

In the case shown in FIG. 1, the scanning lines are L1a, L1
b Since scanning is performed alternately, the count value is assigned to data from the decoder as follows.

[0037]

[Table 1]

As described above, by assigning the scan count value to the decoding result and storing it in the internal memory together with the decoding result, when the counting process is performed later, it is possible to specify which scanning line was used for decoding. can do. In the above case,
An even-numbered scan count value is assigned to data read by the scanning line L1a, and an odd-numbered count value is assigned to data read by the scanning line L1b.

The comparison / determination unit 18 sums up the decoding results of L1a and L1b within a fixed time from the start of reading or within the reading time using an external trigger.
The comparison and determination of the decoding result in each scanning line are performed. When the decoding results do not match, the comparing / determining unit 18 determines that at least one of the decoding results is an erroneous reading,
Discard these decryption results.

That is, for example, when the respective scanning lines obtain the decoding results of 1234 and 1235 within the reading time as described above, if 1234 is the correct answer data and 1235 is the erroneous reading data, the following applies to the scanning line L1a. Data is obtained. 2: 1234 4: 1234 6: 1235 The following data is obtained on the scanning line L1b: 3: 1235 5: 1235 7 :? (No read) When the majority decision of the data is performed, the result of the scanning line L1a is 1234, and the result of the scanning line L1b is 1235. In this case, since the same barcode label is scanned, different results are produced depending on the scanning line. Therefore, it is not known which data is correct, that is, it is understood that one of the decoding results has an erroneous reading. Therefore, the decoding result is discarded because the decoding result is not reliable.

The output unit 19 outputs the decoding result from the comparison / determination unit 18 to an external device (not shown).

Next, the bar code reader 1 of the present embodiment
The operation of 0 will be described with reference to FIG. 2, the light beam emitted from the light source 11 passes through the hole of the perforated mirror 20 and is reflected by the high-speed rotating polygon mirror 12, thereby forming a double scanning beam. L1a and L1b are scanned for the barcode 14a on the barcode label 14.

At this time, the scanning beam detector 13 detects the scanning beams L1a and L1b, as indicated by reference numeral A2, counts up, and outputs the count value to the comparison / determination unit 18. In this case, if the scanning beam detector 13 outputs an even count value for the scanning beam L1a, the scanning beam detector 13 outputs an odd count value for the scanning beam L1b.

Then, the scanning beam L 1 scans the bar code 14 a on the bar code label 14, whereby
Light L2a, L2b reflected by the bar code 14a is reflected again by the high-speed rotating polygon mirror 12, and
The light returns toward 1 and is reflected by the perforated mirror 20 and enters the light receiving unit 15 as indicated by reference numeral A3.

As a result, the light receiving section 15 detects the reflected lights L2a and L2b, respectively, and outputs an analog signal corresponding thereto, as indicated by reference numeral A4. In response to this, the AD converter 16 outputs a binary digital signal corresponding to the white bar portion and the black bar portion of the bar code 14a based on these analog signals, as indicated by reference numeral A5. Then, as indicated by the symbol A6, the decoder 17 outputs each of the scanning beams L1a, L1 from the AD converter 16.
Based on a series of binarized digital signals by the reflected lights L2a and L2b corresponding to 1b, the barcodes are respectively decoded, and the decoding results are output to the comparison / determination unit 18.

In response to this, the comparison / determination unit 18 sets the code A
As shown by 7, based on the count value as a detection signal from the scanning beam detector 13, the count value is assigned to the decoding result from the decoder 17 and the bar code decoding result is compared. That is, the comparison / determination unit 18 is
By assigning an even-numbered count value to the decoding result corresponding to the reflected light L2a and an odd-numbered count value to the decoding result corresponding to the reflected light L2b, two even-numbered and odd-numbered count values are assigned. Decryption results can be obtained. Accordingly, the comparison / determination unit 18 classifies the decoding results based on the count value and compares the decoding results, thereby comparing the decoding results of the reflected lights L2a and L2b corresponding to the scanning beams L1a and L1b. .

When the decryption results to be compared match, the comparison / determination unit 18 outputs to the output unit 19 that the decryption result is correct, as indicated by reference numeral A8. When the decryption results to be compared do not match, the comparison / determination unit 18 determines that at least one of the decryption results is an erroneous read and discards both decryption results, as indicated by reference numeral A9. In order to perform reading, symbols A1 to
The operation of reference numeral A7 is repeated. Finally, the output unit 19 outputs the correct decryption result from the comparison / determination unit 18 to an external device, as indicated by reference numeral A10.

As described above, according to the bar code reader 10 of the embodiment of the present invention, the double scanning beams L1a, L1a,
The bar code 14 on the bar code label 14 is obtained by L1b.
a is scanned. Then, these scanning beams L1
a, the decoding result of the barcode by the pattern of L1b,
The comparison is made by the comparison / determination unit 18, and only when the two decoding results match, the decoding result is output to the external device via the output unit 19 as being correct. Therefore, only a correct decoding result is output from the output device 19.

In this case, the comparison / judgment unit 18 compares the decoding result consisting of a series of binarized digital signals by the reflected lights L2a and L2b corresponding to the respective scanning beams L1a and L1b, thereby decoding the entire decoded bar code. Since the comparison is performed, a more accurate decoding result can be obtained, and when the decoding results do not match, both decoding results are discarded, so that an incorrect decoding result is not output. Further, according to the barcode reading device 10, it is possible to output a high-precision decoding result at low cost without using a plurality of barcode reading devices.

In the above-described embodiment, the high-speed rotating polygon mirror 12 is used as the scanning mechanism.
However, the present invention is not limited to this, and other scanning mechanisms can be used. Further, in the above-described embodiment, the perforated mirror 20 is used as the light splitting means. However, the present invention is not limited to this, and other light splitting means such as a half mirror and a beam splitter may be used. is there.

[0051]

As described above, according to the present invention, a bar code is decoded by generating a plurality of scanning beam patterns by a scanning mechanism and reading a bar code by each scanning beam pattern. The decoding result for each scanning beam pattern is compared by a comparison / determination unit, and only when the decoding results match, the decoding result is output to an external device via an output unit. This allows a single barcode reader to read barcodes using a plurality of scanning beam patterns without using a plurality of barcode readers as in the related art, and decodes each scanning beam pattern. The results are compared by a comparison / determination unit, and only correct decoding results are output to an external device via an output unit.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a barcode reading device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the barcode reading device of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of an example of a conventional barcode reading device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 bar code reader 10 a scanning window 11 light source 12 high-speed rotating polygon mirror (scanning mechanism) 13 scanning beam detector 14 bar code label 14 a bar code 15 light receiving unit 16 AD converter 17 decoder 18 comparison / determiner 19 output device 20 hole Opening mirror (light splitting means) L1a, L1b Scanning beam L2a, L2b Reflected light

Claims (6)

[Claims] 1. A scanning mechanism generates a scanning beam from a light beam emitted from a light source, scans the scanning beam on a bar code label, receives the reflected light at a light receiving unit, and receives the reflected light from the light receiving unit. The analog signal was converted to a binary digital signal, the bar code was decoded by a decoder, and the decoding result was output to an external device by an output device.
A barcode reading device, wherein the scanning mechanism is configured to generate a plurality of scanning beam patterns, and a decoding result of a barcode obtained by each of the scanning beam patterns is compared, and the decoding results match. Only when
A bar code reader comprising a comparison / determination unit that outputs a decoding result to an output unit. 2. The apparatus according to claim 1, further comprising a scanning beam detector for detecting each of the scanning beam patterns, wherein the comparison / determination unit compares the decoding result of the barcode based on the detection result of the scanning beam detector. The bar code reader according to claim 1, wherein 3. The scanning beam detector is a counter, and outputs a count value which is incremented each time a scanning beam pattern is detected. The comparison / determination unit outputs a count value from the scanning beam detector. 3. The bar code reader according to claim 2, wherein a count value is assigned to the decoding result from the decoding device based on the result, and the decoding result of the bar code is compared. 4. The barcode reader according to claim 1, wherein said scanning mechanism is a high-speed rotating polygon mirror. 5. The bar code reader according to claim 4, further comprising a light branching unit that branches reflected light from the bar code label toward the light source via the high-speed rotating polygon mirror. 6. The bar code reader according to claim 5, wherein the light splitting means is a perforated mirror.