JPH10240852A - Code information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent code information from being misread by counting matches while regarding the same code information obtained from the same scanning line as one piece of code information. SOLUTION: When a read frequency (m) recorded in a read frequency area reaches a certain value (>N), a bar code information decision part compares or retrieves pieces of bar code information by scanning lines which are stored in a bar code information area of a bar code information storage memory 24 and judges bar code information having more than one match as correct bar code information. Further, a scanning line number (n) is managed and bar code information obtained from the same scanning line is handled as one piece of bar code information even in case of a match. Therefore, even when code information is misread on only one scanning line and unreadable on other scanning lines, the number of matches of the misread code information does not increase, so the misread code information is never judged as proper code information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a code information reading apparatus. For example, the present invention relates to a code information reading device such as a raster scan type bar code reader.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional bar code reader 1 of a raster scan system. In the bar code reader 1, a light beam 2 emitted from the bar code reader 1 is scanned on a bar code 4 along a plurality of scanning lines 3, and the light beam 2 reflected by the bar code 4 is converted into a bar code. Reader 1
And bar code information is decoded based on the light intensity signal received by the bar code reader 1.

The raster scanning method in which the light beam 2 is scanned along a plurality of scanning lines 3 as described above can improve the bar code reading rate and the reading accuracy as compared with a single scanning line bar code reader. There are advantages that can be done. That is, if the light beam is scanned along a single scanning line, the barcode is printed thinly, a part of the barcode is chipped or dirty, and wrinkles are formed on the barcode printed label. For this reason, when the barcode reading conditions are poor, there is a high possibility that the barcode becomes unreadable or misread. Therefore, by reading the barcode 4 at a plurality of positions by scanning the light beam 2 along the plurality of scanning lines 3, the reading rate and reading accuracy of the barcode 4 are improved.

In such a raster scan type bar code reader, even when the same bar code is being read, the reading conditions are different depending on the position of the scanning line. The barcode information decoded corresponding to the scanning line may not coincide with each other. Further, depending on the position of the scanning line, the bar code may not be able to be decoded. Therefore, in the conventional raster scan type bar code reader, when the bar codes decoded for each scan match a predetermined number of times (a plurality of times) consecutively, it is determined that the bar code information is correct and the reading is completed. I am trying to do it. As an example, as shown in FIG. 2, the light beam 2 is transmitted along N scanning lines of scanning line numbers n = 1 to N (the total number N of the scanning lines is determined by the number of surfaces of the polygon mirror, etc.). For example, in the case of a barcode reader that reads a barcode by scanning, and completes the barcode reading by, for example, four consecutive matches, if the read barcode information matches at scanning lines n = j to j + 3, another bar code is read. Even if the code information has been read, the barcode information read by the scanning lines n = j to j + 3 is determined to be correct barcode read information, and the reading is completed. This prevents erroneous reading of the barcode and improves reliability.

[0005]

In the raster scan type bar code reader 1 as described above, if the decoded bar code information matches a plurality of times consecutively, it is determined that the bar code information is correctly read. However, since the barcode reader repeatedly scans all the scanning lines over and over again, if an erroneous reading is performed only on one scanning line, a barcode is consecutively matched a plurality of times and erroneous reading occurs. . That is, in the case shown in FIG. 2, the bar code reader scans the scanning lines n = 1, n = 2,... N = N, and returns to the scanning line n = 1 again when the scanning of the scanning line n = N is completed. To scan each scanning line, and repeatedly scan all the scanning lines many times. For this reason,
When the reading condition is very bad and the reading is erroneous at the scanning line n = j and the reading is not possible at all the other scanning lines n ≠ j, the same bar code information is erroneously read at the same scanning line n = j. As a result, a plurality of consecutive matches may be established on the same scanning line. In this case, the erroneously read barcode information is output as correct barcode information.

For this reason, in a conventional raster scan type bar code reader, reading is completed with a plurality of consecutive matches, but the bar code reading reliability has not always been improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to read code information by a method of reading code information by scanning light beams on a plurality of scanning lines. An object of the present invention is to prevent code information from being erroneously read.

[0008]

SUMMARY OF THE INVENTION A code information reader according to claim 1 reads code information for each scan by scanning a light beam along a plurality of different scanning lines, and based on the number of coincidences of each code information. In a code information reading apparatus that determines proper code information, the same code information obtained from the same scanning line is provided with a code information determination unit that counts the number of matches as one code information.

According to the first aspect of the present invention, the same code information obtained from the same scanning line is one.
Since the number of matches is counted as two pieces of code information, even if the same code information is repeatedly misread on the same scanning line, the number of matches does not keep increasing, and the number of matches of the code information is only one.

Therefore, even if the code information is erroneously read on one scanning line and cannot be read on another scanning line, the number of coincidences of the erroneously read code information does not increase. It is not determined that the code information is appropriate.

According to a second aspect of the present invention, there is provided a code information reading apparatus.
In a code information reading device that reads code information by scanning a light beam along a plurality of different scanning lines and determines appropriate code information, a light beam is scanned along each scanning line to perform scanning for each scanning. Read the sign information,
It is characterized by including code information determining means for determining appropriate code information based on the read rate obtained from the code information.

According to a second aspect of the present invention, there is provided a code information reading apparatus.
Since the proper code information is determined based on the reading rate, even if the same code information is repeatedly misread on the same scanning line,
As a result, the reading rate does not increase.

Therefore, even if the code information is erroneously read only on one scan line and cannot be read on another scan line, the read rate of the erroneously read code information does not increase. It is not determined that the code information is appropriate.

According to a third aspect of the present invention, there is provided a code information reading apparatus.
In a code information reading device that reads code information by scanning a light beam along a plurality of different scanning lines and determines appropriate code information, each code information is read along one of all scanning lines.
It is characterized by comprising code information discriminating means for scanning the light beam to read and determine the code information, and then erases all the stored code information.

According to a third aspect of the present invention, there is provided a code information reading apparatus.
After reading the code information of one scan (one raster scan), all the code information is erased. Therefore, the code information is read and the proper code information is determined using only the code information of one scan. . Therefore, even if the same code information is repeatedly erroneously read, it is merely code information for a different determination, and does not affect each other's determination.

Therefore, even if the code information is erroneously read only on one scanning line and cannot be read on another scanning line, the erroneously read code information is not judged as proper code information.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) The code information to be read by the code information reading apparatus of the present invention is not limited to various barcodes, but includes any type such as a matrix code. An example of a target barcode reader will be described.

FIG. 3 is a schematic block diagram showing a bar code reader 6 according to one embodiment of the present invention. The light projecting system of the bar code reader 6 mainly includes a semiconductor laser element (L
D) 7, an LD drive circuit 8, a light projecting lens 9 and a polygon mirror 10. When the semiconductor laser element 7 is driven by the LD drive circuit 8, the semiconductor laser element 7 emits pulse light. The light beam 2 emitted from the semiconductor laser element 7 is collimated by the light projecting lens 9 and is incident on the mirror surface of the polygon mirror 10. The light beam 2 reflected by the mirror surface is projected toward the bar code 4. Is done. The polygon mirror 10 is a polygonal mirror in which a mirror surface is formed on an outer peripheral surface of a regular polygonal prism, and is rotated at a constant speed by a servomotor (not shown). Therefore, the light beam 2 reflected by the polygon mirror 10 is scanned in a direction orthogonal to the rotation axis of the polygon mirror 10 as the polygon mirror 10 rotates. Further, since each mirror surface of the polygon mirror 10 is inclined at a different angle with respect to its rotation axis, the light beam 2 reflected by each mirror surface is raster-scanned on a different scanning line 3 as shown in FIG. Is done. For example, if the number of mirror surfaces of the polygon mirror 10 is 10, the light beam 2 is 1
Scanning is performed sequentially along zero scanning lines 3.

Reference numeral 11 denotes an end detecting light receiving element provided at the end of the scanning area of the light beam 2 scanned by the polygon mirror 10, and receives light when the light beam 2 reaches the end of the scanning area. The end of the optical scan along each scan line is detected.

The light receiving system of the bar code reader 6 mainly includes a light receiving lens 12, a light receiving element 13 such as a photodiode (PD), an I / V (current / voltage) conversion circuit 14,
It comprises an AGC circuit (auto gain controller) 15, a binarization circuit 16, a decoder 17, a barcode information discriminator 18 and an output circuit 19. The light beam 2 scanned on the bar code 4 is diffusely reflected on the surface of the bar code 4 and then condensed on the light receiving element 13 by the light receiving lens 12. Since a photocurrent according to the amount of received light flows through the light receiving element 13, the photocurrent is converted into a light receiving signal (voltage) by the I / V conversion circuit 14. Light reception signal is bar code 4
AGC circuit 15 performs processing so that the signal amplitude becomes a constant value so that the signal can be stably read even if the state changes, and then a time corresponding to the bar code width is obtained by the binarization circuit 16. It is converted into a width binarized signal (hereinafter referred to as read data). The read data obtained every time the light beam is scanned in this manner is translated (decoded) by the decoder 17 as bar width information of the bar code 4. Bar code information obtained by translating the read code by the decoder 17 is sent to the bar code information discriminating unit 18. The barcode information determining unit 18 determines whether there is barcode information that can be determined to be correct by comparing or searching for a plurality of barcode information obtained for each scanning line, and determines whether the barcode information can be determined to be correct. If the information exists, the barcode information is extracted and output from the output circuit 19 to an external device.

The decoder 17 used here is composed of 2
In order to capture the quantified read data at high speed, DM
A (direct memory access) method is used. The configuration of the decoder 17 is shown in the block diagram of FIG. The decoder 17 logically alternately switches between two buffer memories (RAMs) 22 and 23 by the DMA controller 20 to execute data reading processing and translation processing in parallel, and is translated by the central processing unit (CPU) 21. The barcode information stored in the barcode information storage memory 24
Is to be written to. FIGS. 5A and 5B are diagrams showing the data structure of the buffer memories 22 and 23 for storing read data. FIG. 5A shows a read data area for storing read data, and FIG. And a scanning line number area for storing the scanning line numbers of the above. FIG. 5C shows a barcode information storage memory 24 for storing the translated barcode information.
Is a diagram showing a data structure of a scan line number n = 1
To N, and a read count area for recording the read count m of the translated bar code information.

Thus, the binarization circuit 16 sends the decoder 1
When the read data is input to 7, the DMA controller 20 stores the read data together with the corresponding scan line number in one buffer memory. For example, FIG.
As shown in (a), the scan line number ni and the read data Ri are stored in the scan line number area and the read data area of the buffer memory (RAM) 22, respectively. At the same time, the DMA controller 20 reads out the read data and its scan line number stored in the other buffer memory 23 and transfers them to the central processing unit 21. For example, a buffer memory (RAM) as shown in FIG.
The read data Rj and the scan line number nj stored in the read data area 23 and the scan line number area are read and transferred to the central processing unit 21. Central processing unit 2
1 is read data transferred based on a barcode rule stored in a memory (ROM) 25 in advance;
For example, Rj is translated (decoded) into barcode information Tj,
This is stored in the storage location (n = nj) designated by the corresponding scanning line number nj in the barcode information storage memory 24. However, if the read data cannot be translated, an unacceptable code such as “?” Is stored at the corresponding position in the barcode information area. The value m of the read count area is incremented by one each time the translation is successful.

When the number of readings m recorded in the number-of-readings area reaches a certain value (> N), the barcode information discriminating section 18 stores each barcode information stored in the barcode information area of the barcode information storage memory 24. The barcode information for each scanning line is compared or searched, and the barcode information that matches a plurality of times is determined to be correct barcode information, and the reading is completed. n is managed, and even if the barcode information obtained from the same scanning line matches, the barcode information is treated as one barcode information, and is not determined as a match for a plurality of times. More specifically, as shown in FIG. 5C, the storage location of the barcode information area is set equal to the number of scanning lines, and when barcode information of a certain scanning line number is stored, the barcode information area is stored. The barcode information stored in the barcode information area is overwritten. Therefore, only one barcode information corresponding to each scanning line number is stored in the barcode information area, and the barcode information discriminating section 18 simply checks the barcode information stored in the barcode information area for the coincidence of the barcode information. You just need to search for the number.

Next, an algorithm for reading a bar code in the bar code reader 6 will be described with reference to the flow charts of FIGS. When the barcode reader 6 starts the reading operation, first, an initialization process is executed (S31). That is, the value of the scan line number n stored in the scan line number area [FIGS. 5A and 5B] of the buffer memories 22 and 23 is cleared (n = 0), and the read data area [FIG. ) (B)], the read data stored therein is cleared (an impossible code “?” Is stored). Further, all the barcode information stored in the barcode information area [FIG. 5 (c)] is cleared (impossible code "?" Is stored), and the number of readings area [FIG. 5 (c)]
Is cleared (m = 0).

Next, the process waits until a read instruction is received (S32). When the read instruction is received, the LD driving circuit 8 causes the semiconductor laser element 7 to emit light and scan the light beam 2 (raster scan) (S33). At the same time, the light beam 2 reflected by the bar code 4 is received by the light receiving element 13 and the light receiving signal is processed by the binarization circuit 16 or the like, and the read data R1 is output. This read data R1 is D
The storage is started in the buffer memory 22 specified by the MA controller 20 (S34).

Then, storage of the read data R1 is continued until the edge detecting light receiving element 11 arranged at the end of the scanning area receives the light beam 2 (S35, S52). When it is detected that the beam 2 has reached the end of the scanning area (S35), the storage of the read data R1 in the buffer memory 22 is stopped (S3).
6). When the read data R1 for one scan line is stored in the read data area of the buffer memory 22 in this manner, the data storage destination is switched to the buffer memory 23 by the DMA controller 20, and the next scan line n = 2
Is started to be stored in the buffer memory 23 (S37). Next, the scan line number is incremented by 1 (n = 1) and stored in the scan line number area of the buffer memory 22 in which the read data R1 has been stored.

Thereafter, the central processing unit 21 reads and translates the read data R1 stored in the buffer memory 22 (S41). If the translation is impossible, an unacceptable code “?” Is stored in the storage location (n = 1) in the barcode information area corresponding to the scanning line number stored in the scanning line number area. Store (S4
2, S43).

If the translation is successful in step S42, the bar code information is read from the storage location (n = 1) in the bar code information area corresponding to the scanning line number in the scanning line number area and translated. It is checked whether it matches the barcode information (S44).

If the collation results match, the barcode information stored in the storage location (n = 1) is stored as it is. If the collation results do not match, the corresponding barcode information in the barcode information area is stored. The translated new barcode information is stored in the location and the data is updated (S45).
However, since the bar code information area initially stores an unacceptable code "?", The bar code information that has been successfully translated is stored in the bar code information area, and the number of times of reading in the number of readings area is increased by one ( m = 1) (S46).

When the processing for the scanning line number n = 1 is completed as described above, the edge detection light-receiving element 11 disposed at the end of the scanning area is turned on for the second scanning line (n = 2). Read data R until beam 2 is received
The storage of 2 is continued (S35, S52). When the end of the second scan is detected (S35), the storage of the read data R2 in the buffer memory 23 is stopped (S36), the other buffer memory 22 is cleared, and the next scan line (n = 3) is used. The storage of the read data R3 is started (S37). Next, the scan line number is incremented by 1 (n = 2) and stored in the scan line number area of the buffer memory 23 where the read data R2 has been stored (S38).

Thereafter, the read data R2 in the buffer memory 23 is translated in the same manner as in the case of the first scanning line (S41). If translation is impossible, the barcode information in the barcode information storage memory 24 is read. The impossible code "?" Is stored in the storage location n = 2 of the area (S42, S43). If the translation is successful, the translated barcode information is stored in the storage location n = 2 of the barcode information area ( S42, S4
4, S45), the number of readings m in the number of readings area is increased by 1 (S46).

The above processing is performed by using the number of scanning lines (N lines).
By repeating the above, the translated barcode information T1 to TN or the unacceptable code "?" Is stored in the barcode information area n = 1 to N of the barcode information storage memory 24. At this time, when the scanning line number n increases by 1 and reaches the maximum value N, it is immediately cleared (n = 0) (S38 to S4).
0).

Therefore, after this, the bar code is scanned,
Read data Ri (i = 1 to N) and scan line number ni
Is stored in the buffer memories 22 and 23 (S35 to S35).
(S40), the read data Ri is translated (S41), and if the translation is not possible, the impossible code "?" Is stored in the corresponding storage position ni in the barcode information area (S4).
2). If the translation is successful, the barcode information (old information) stored in the corresponding storage location ni in the barcode information area is compared with the translated barcode information (new information) (S44), and a match is obtained. In this case, the barcode information stored in the storage location ni in the barcode information area is not updated and is stored as it is. If the collation does not match, the data at the storage location ni is updated to new barcode information (S45), and the number of readings m is increased by 1 (S46).

When the light beam is raster-scanned many times over the bar code and repeatedly scanned on the same scanning line,
Barcode information is obtained for each scan and stored in the barcode information area of the barcode information storage memory 24.
As shown in FIG. 5C, the barcode information area includes
There are only storage positions corresponding to the number of scanning lines, and only one barcode information obtained from the same scanning line is updated and stored.

Each time the bar code information is stored in the bar code information area, the number of readings m increases by one. When the number of readings reaches a set value (when the number of scanning lines is N, the set value is set to, for example, 10N). (Set) (S4)
7) The same number of the same data in the barcode information stored in the barcode information area is a specified number (for example, N / 2)
A search is made as to whether there is any more (S48). If the same bar code information is present in the bar code information area in a predetermined number or more, the semiconductor laser element 7 is turned off (S49), and the bar code information is extracted and output from the output circuit 19 (S5).
0), and further outputs a read success (OK) signal (S)
51).

In steps S35 and S52, if it is on standby until the end detecting light receiving element 11 receives the scanning end pulse, it is monitored whether a reading end instruction is received (S52). If you receive
The storage of the read data is interrupted (S53), the semiconductor laser element 7 is turned off (S54), the data in which the reading has failed (NG) is output (S55), and the signal of the reading failure (NG) is output (S56). ).

In step 48, the number of the same data in the bar code information area is searched to determine whether or not the same data is equal to or more than the specified number. In this case, it is preferable to extract the data having the largest number of the same data as the barcode information. Alternatively, in such a case, an error may be set. Further, as the determination method in step 48, it may be determined whether or not the number of consecutive matches of the barcode information that continuously matches in the barcode information area is equal to or greater than a specified number.

(Second Embodiment) FIG. 8 is a diagram showing a data structure of a barcode information storage memory 24 according to another embodiment of the present invention. In this embodiment, as shown in FIG. 8, barcode information obtained from the same scanning line is stored in different storage positions in the barcode information area.
That is, assuming that the number of scanning lines is N and the number of repetitions of the raster scan is 10, for example, 10N storage positions are secured in the barcode information area.

In this embodiment, the bar code information from the same scanning line is stored in the bar code information area in duplicate, and when the central processing unit 21 counts the same data, the same scanning line is used. The same barcode information corresponding to the number is processed by software so as to be counted only once, and the number of the same data is counted.

Although the data of the same scanning line can be prevented from being counted redundantly by such a method, the method of the first embodiment is more memory efficient, and the processing in the central processing unit 21 is also improved. It's easy.

(Third Embodiment) FIGS. 9 and 10 are flowcharts showing an algorithm for reading a barcode by a barcode reader according to another embodiment of the present invention. In this embodiment, every time all the scanning lines are scanned once (hereinafter, this is referred to as one raster scan), it is determined whether or not the barcode information has been read, and every bar scan in the barcode information area is performed every raster scan. This clears the code information. In FIGS. 9 and 10, the same reference numerals are given to portions that execute the same processes as those in the flowcharts of FIGS. 6 and 7. FIG. 11 is a diagram showing the data structure of the barcode information storage memory 24. In the barcode information area of the barcode information storage memory 24 in this embodiment, barcode information and the number of coincidences (the number of times of reading) qi are stored for different data. Since the configurations of the barcode reader and the buffer memory are the same as those of the first embodiment, they are omitted (FIGS. 3, 4 and 5A).
(B)).

Hereinafter, this embodiment will be described with reference to FIGS. As in the case of the first embodiment, the read data read for each scanning line is alternately stored in the buffer memories 22 and 23 together with the scanning line number (S31 to S38).

Next, the data read from the buffer memories 22 and 23 are translated into bar code information (S61), and it is determined whether the translation is successful (S62). If translation is impossible, the data of the next scanning line is processed. . If the translation is successful, a search is made to determine whether the barcode information matches any of the barcode information already stored in the barcode information area (S65). The code information is registered in an empty area of the bar code information area, and the number of matches qi of the bar code information is registered.
Is stored as 1 (S66, S67).

On the other hand, if any of the bar code information stored in the bar code information area matches the translated bar code information, the corresponding bar code information in the bar code information area is displayed. The number of information matches qi is increased by 1 (S68). Then, it is determined whether or not the number of matches qi has reached a specified value (for example, N / 2) (S6).
9) If the specified value has not been reached, step S35
The following process is repeated, and when the specified value is reached, the process is terminated and the barcode information is output from the output circuit 19 (S49 to S51). That is, in this embodiment,
Manages only different barcode information and the number of matches qi,
Barcode information in which the number of matches qi (that is, the reading rate qi / N) reaches the specified value earliest with respect to the number N of scanning lines is extracted and output.

In steps S63 and S64, when the scanning line number is managed and the scanning line number becomes equal to the maximum value, that is, the total number N of the scanning lines, initialization processing is performed and the buffer memories 22, 23 and Since the data in the barcode information storage memory 24 has been cleared, the number of matches qi
Is calculated only within one raster scan, and bar code information from the same scanning line is not evaluated redundantly. Therefore, as described in the conventional example, even when the reading is erroneous on only one scanning line and the translation is impossible on all other scanning lines, the number of coincidences qi of the erroneously read barcode information is only one, and Misread bar code information is not output.

The specified value for the number of matches may be a fixed value or may be settable by the user.

(Fourth Embodiment) FIGS. 12 and 13 are flowcharts showing an algorithm for reading a barcode by a barcode reader according to still another embodiment of the present invention. In this embodiment, the reading rate of barcode information is managed, and if the reading rate is equal to or greater than a specified value, it is determined that the barcode has been successfully read. 12 and 13, the same reference numerals are given to the portions that execute the same processes as those in the flowcharts of FIGS. 6 and 7. FIG. 14 shows a barcode information storage memory 24.
FIG. 3 is a diagram showing a data structure of FIG. In the barcode information area of the barcode information storage memory 24 in this embodiment, barcode information and the number of coincidences (the number of times of reading) qi are stored for each different data. The number of times J is stored. The configuration of the barcode reader and buffer memory is the first
Since it is the same as the embodiment of FIG.
(FIGS. 5A and 5B). However, the center axis of the polygon mirror is inclined with respect to the rotation axis of the motor for raster scanning.

Hereinafter, this embodiment will be described with reference to FIGS. As in the case of the first embodiment,
The read data read for each scanning line is alternately stored in the buffer memories 22 and 23 together with the scanning line number (S31 to S38). In this embodiment, the number of raster scans J stored in the number of raster scans area is also cleared in the initialization processing of step S31 (J = 0).

Next, the data read from the buffer memories 22 and 23 are translated into bar code information (S71), and it is determined whether or not the translation is successful (S72). If translation is impossible, the data of the next scanning line is processed. . If the translation is successful, a search is made to see if the barcode information matches any of the barcode information already stored in the barcode information area (S73). The code information is registered in an empty area of the bar code information area, and the number of matches qi of the bar code information is registered.
Is stored as 1 (S74, S75).

On the other hand, if any of the bar code information stored in the bar code information area matches the translated bar code information, the corresponding bar code information in the bar code information area is displayed. The number of information matches qi is increased by 1 (S76).

Thus, the buffer memories 22 and 23
The barcode information is alternately translated, and if the translation is successful, new barcode information is stored in the barcode information area, or the number of matches qi of the already registered barcode information is increased by one. Processing (S71-S
When the scanning line number n reaches the maximum value N by repeating (76) for one raster scan (S77), the number of raster scans J in the raster scan count area is increased by 1 (S78).

Next, the bar code information discriminating section 18 obtains a reading rate. That is, the reading rate qi / (N × J) is calculated from the number of matches qi of each barcode information Ti stored in the barcode information area of the barcode information storage memory 24 (S79). Then, the obtained reading rate qi / (N
× J), it is determined whether or not there is one having a specified value (for example, 0.5) or more (S80). If there is one having the specified value or more, the barcode information is determined to be correct barcode information. The determination is made, and the barcode information is output from the output circuit 19 (S49 to S51). At this time, if a plurality of barcode information whose reading rate is equal to or more than the specified value is extracted,
Of these, the barcode information with the largest read rate may be determined to be correct barcode information.

On the other hand, if there is no bar code information with the reading rate qi / (N × J) being equal to or more than the specified value, only the scanning line numbers in the scanning line number areas of the buffer memories 22 and 23 are cleared ( S81). In this case,
Continue reading and translating the barcode, update the number of coincidences qi of the barcode information, and each time one raster scan process is performed, determine whether or not there is one with a reading rate equal to or greater than a specified value. If the reading rate is equal to or more than the specified value, the reading is completed, and if not, processing for one raster scan is further executed.

Therefore, in this embodiment, the reading rate of different bar code information is searched for each raster scan to find one having a specified rate or more. Extract and output information.
With such a method of managing the reading rate, as described in the related art, even if the reading error occurs only on one scanning line and the translation cannot be performed on all the other scanning lines, the error reading bar can be read. The read rate of the code information is J / (N × J) =
This is only 1 / N, and misread bar code information is not output.

Further, in the conventional bar code reader, the reading rate is confirmed by a field test before the actual operation, but the reading rate cannot be confirmed during the actual operation. However, in this method, it is possible to output and display the barcode reading rate even during actual driving.

Note that the prescribed value relating to the reading rate may be a fixed value or may be settable by the user.

(Other Methods) As still another method, the method of the first embodiment and the method of the third or fourth embodiment are used together, and when the output results from both methods match. Only the barcode information may be output. As a result, the accuracy of the barcode information determination can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a conventional raster scan type bar code reader.

FIG. 2 is a diagram showing a plurality of scanning lines scanned on a barcode.

FIG. 3 is a schematic block diagram illustrating a configuration of a barcode reader according to an embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a decoder according to the embodiment.

FIGS. 5A, 5B, and 5C are diagrams showing a data structure of a buffer memory and a barcode information storage memory used in the decoder of the above.

FIG. 6 is a flowchart showing an algorithm for reading a barcode in the barcode reader according to the embodiment.

FIG. 7 is a partial flowchart showing a part of the flowchart of FIG. 6;

FIG. 8 is a diagram showing a data structure of a barcode information storage memory in a barcode reader according to another embodiment of the present invention.

FIG. 9 is a flowchart illustrating an algorithm for reading a barcode in a barcode reader according to yet another embodiment of the present invention.

FIG. 10 is a partial flowchart showing a part of the flowchart in FIG. 9;

FIG. 11 is a diagram showing a data structure of a barcode information storage memory in the embodiment.

FIG. 12 is a flowchart illustrating an algorithm for reading a barcode in a barcode reader according to yet another embodiment of the present invention.

FIG. 13 is a partial flowchart showing a part of the flowchart of FIG. 12;

FIG. 14 is a diagram showing a data structure of a barcode information storage memory in the embodiment.

[Explanation of symbols]

 2 light beam 4 bar code 7 semiconductor laser element 10 polygon mirror 13 light receiving element 17 decoder 18 bar code information discriminating unit 20 DMA controller 21 central processing unit (CPU) 22, 23 buffer memory 24 bar code information storage memory

Claims (3)

[Claims] 1. A code information reading apparatus which reads code information for each scan by scanning a light beam along a plurality of different scanning lines and determines appropriate code information based on the number of coincidences of each code information. A code information reading apparatus comprising: code information determination means for counting the number of coincidences as the same code information obtained from the same scanning line as one code information. 2. A code information reading apparatus for reading code information by scanning a light beam along a plurality of different scanning lines and determining proper code information, wherein the light beam is scanned along each scanning line. A code information reading device comprising: code information reading means for reading code information for each scan and determining appropriate code information based on a reading rate obtained from the code information. 3. A code information reading apparatus for reading code information by scanning a light beam along a plurality of different scanning lines and determining proper code information, wherein each of the light beams is scanned once along all the scanning lines. A code information reading device comprising: code information reading means for scanning and performing code information reading and determining, and then deleting all stored code information.