JP3504366B2 - Symbol information reading device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a symbol information reading device for reading symbol information such as a bar code and outputting processing information.

[0002]

2. Description of the Related Art Generally, there is a bar code in which a plurality of bars and spaces are alternately arranged as symbol information representing various kinds of information. This barcode is usually printed directly on the article or printed on a sticker or the like and attached to the article.

However, in the case where it is desired to keep the existence of the bar code secret to a third party, or when the bar code is not printed due to the design of the article but the distribution management is desired, the conventional method is used. Visible printing was inconvenient.

Therefore, Japanese Laid-Open Patent Publication No. 3-15487 discloses that
A bar code printing method has been proposed in which printing is performed with an invisible material such as photoluminescence ink in a normal light source (including sunlight).

When reading this invisible bar code, when light of a specific wavelength (for example, near infrared rays) is irradiated, radiant light of another wavelength is reflected and this radiant light is read.

[0006]

However, since the bar code printed using the ink of the above-mentioned invisible material is invisible, it is difficult to notice the deterioration due to heat, sunlight, etc., and these deteriorations are caused. Causes a read error. Further, deterioration of the label due to use, stains on the surface, and the like also cause reading errors.

Therefore, when the user reads the bar code, he / she first notices that the bar code is in the unreadable state after the reading error. When the bar code printed on the card or the like becomes unreadable, the card is defective. After the revelation of the card failure, to be able to re-issue immediately, until it is re-issued, will not be able to use the card, it has become a problem in the operational aspects of the card. The present invention represents a quality state of the two-dimensional <br/> barcode number, and to provide symbol information reading apparatus capable of grasping the deteriorated state of the two-dimensional bar code.

[0008]

In order to achieve the above object, the present invention comprises a two-dimensional image pickup means for picking up a two-dimensional bar code representing information in a bar and a space as a two-dimensional image. State detection for detecting the state of the two-dimensional barcode as a numerical value from the two-dimensional barcode image obtained by the two-dimensional image capturing means and comparing it with a predetermined threshold to detect the state of the two-dimensional barcode. Means, decoding means for decoding the two-dimensional barcode image captured by the two-dimensional image capturing means into original information, and output for selectively outputting information output from the state detecting means and the composite means The state detecting unit includes a selecting unit and a displaying unit that displays a state of the two-dimensional barcode selected by the output selecting unit, and the state detecting unit includes a state of the two-dimensional barcode.
Is the bar width and radiant light conversion rate, or each codeword
Weight of each block of 2D barcode output in units
The value found, or the number of 2D barcode errors,
From the weighting value for each block of the 2D barcode
Determined error count or 2D bar code
Error determined from the weighting value of each block
Error corrections that could not be corrected when the error was corrected.
One of the number
Storage means for storing each threshold value corresponding to the type of numerical value
There is provided a symbol information reading device having:

[0009]

[Action] above structure symbol information reading device, a two-dimensional imaging means images the two-dimensional bar code as a two-dimensional image, based on the image information, the weighting only young properly condition detecting means bar The bar code status is detected as a numerical value by the width and the radiant light conversion rate. The numerical value is compared with a predetermined threshold value, and if it is equal to or less than the threshold value, it can be read on the display means that an error may occur in the bar code reading thereafter even if the reading is possible at present. Display a warning that an error may occur.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a symbol information reading device as an embodiment according to the present invention. This symbol reading device is roughly classified into a two-dimensional image capturing unit 1 that generates a barcode as a video signal (data) of a two-dimensional image and a data processing unit 2 that processes the read data.
And a control unit 3 that controls all of them and a display unit 4 that performs various displays. Further, in this embodiment, the bar code (bar code label) read by the symbol reading device is, for example, the stacked bar code 5 and is printed on the card 6.

The two-dimensional image pickup unit 1 includes an image forming lens 7
And a two-dimensional image pickup device 8 and an image processing unit 9 for determining the label size of the photographed barcode and updating the matrix. The image processing unit 9 may be a CPU. The stacked bar code 5 imaged on the photoelectric conversion surface of the two-dimensional image pickup device 8 by the imaging lens 7 is photoelectrically converted and generated as a video signal, and the bar code together with the label size determined based on the video signal. It is output to the data processing unit 2 as information.

As shown in FIG. 2, the data processing unit 2 is
A barcode information memory 11 for temporarily storing barcode information input as a video signal from the two-dimensional image pickup unit 1, and various registers for storing various constants and variables for determining the state of the barcode. And a reading unit 13 for reading necessary barcode information or constants and variables from the barcode information memory 11 or the memory 12, and a state of the barcode 5 from the barcode information and various constants and variables. State detector 14
And a decoding unit 15 that decodes the barcode information into the original information from the two-dimensional image, and an output selection unit 16 that selectively outputs the information output from each of the above-mentioned components. The state detection unit 14 determines the quality of the barcode 5 based on the detected state of the barcode 5, and even if the barcode 5 is currently readable, an error will occur in barcode reading in the near future. If such a situation is possible, a warning to that effect is displayed on the display unit 4 via the output selection unit 16.

FIG. 3 shows an example of the label structure of the stacked bar code 5 used in this embodiment. The bar code label is composed of a combination of a bar code and a space, and is a label portion 21 which is an area of an information component to be composited composed of a bar code character group and start / stop characters arranged before and after the label portion. Start code 22
And a stop code 23.

Then, one code is a stop code 23.
It consists of 4 bars and a space. Also,
The start and stop codes 22 and 23 start from large bars 22A and 23A called "big bars".

The label section 21 is a label composed of a code called a row indicator 21A existing next to the start code 22 and the stop code 23 and a plurality of data columns 21B in which actual data sandwiched between them is described. It is composed of Marix 21C. The row indicator 21A describes the size of the label in the row and column directions, the security level, and the like.

Therefore, by decoding the information of the row indicator, the label information, size, etc. can be determined. The barcode label 5 shown in FIG. 3 is a barcode label having a 4 * 2 label matrix.

Next, the data processing device 2 in this embodiment
Reads label information based on the algorithm shown in the flowchart of FIG. 4 and outputs various generated data to a host computer (not shown) or the like. Here, the operation of reading the label information and decoding it is described in Japanese Patent Application Laid-Open No. HEI-2.
It is described in Japanese Patent Application Laid-Open No.-268383 and Japanese Patent Application Laid-Open No. 3-204793, and detailed description thereof is omitted.

First, the barcode is captured as an image by the two-dimensional image capturing unit 1 and is input to the image processing unit 9 (step S1). It is determined whether or not the image photographed by the image processing unit 9 has a barcode label (step S2).

When it is determined that the bar code label is present (YES), the label size is determined as will be described later (step S3), and the number of columns and the security level are determined.

Next, it is judged whether the label size or the like has been decided (step S4). If not decided (NO), the process returns to the step S1 again, and again.
Take a bar code label.

When the label size and the like are determined in step S4 (YES), the matrix update described later is performed (step S5), and the cluster number and the value are calculated.

Here, the cluster number and value will be briefly described. The cluster number in the bar code shown in FIG. 3, those that are provided to minimize the probability of error occurrence is present in the code word of Te all except the start / stop pattern. The same type of cluster appears repeatedly every third row. For example, row 0
, The codeword of cluster 0, the codeword of cluster 3 in row 1, the codeword of cluster 6 in row 2, and so on.

The value is a codeword value (cod
It is a singular value called "evaluvalue" and has a one-to-one correspondence with a codeword in a cluster. After the matrix is fixed by the matrix update routine, an erasure error is issued.
And the error is corrected (step S6). The erasure error is a state in which the codeword is missing or unreadable. In this case, the position of the codeword is known, but the codeword value is unknown.

Next, it is judged whether or not the error in the bar code is correctly corrected (step S7), and if the error correction is completed properly (YES), the process is moved to the data conversion (step S8) and the process returns. . If the error cannot be corrected (NO), the process returns to step S1 and the
Take a barcode.

In this step S8, the above-mentioned step S2
Then, in step S3, the read and corrected information is decoded into user data (information) and output to a host computer (not shown) or the like.

The subroutine of each item in the flowchart of FIG. 4 described above will be described. The label size determination shown in step S3 of FIG. 4 will be described with reference to the flowchart shown in FIG. In determining the label size, the number of columns and rows are mainly used.
The number and security level are determined.

First, one line of the photographed target image is taken out in accordance with the scanning equation obtained by the label detection routine (step S11). Next, this 1-line data is converted into X-sequence (hereinafter, referred to as X-se
q) to T-sequence (hereinafter T-se)
(set to q) (step S12). Where X
-Seq and T-seq are the widths of each pattern (X
-Seq) and the width of the black and white pattern (T-seq)
Is represented.

Next, the start / stop code is detected (step S13). This start / stop code includes a peculiar start / stop code in the bar code as shown in FIG. 3, and is detected by comparing the start / stop patterns converted into T-seq.

Next, the cluster number and the value are obtained from T-seq (step S14). Actually, a value is obtained by a calculation formula and a table preset with the value is referred to. Next, a resync process is performed when the reading light crosses a row (step S1).
5). For example, when scanning across rows, eight pieces of X-seq data do not necessarily describe one codeword. Therefore, it is necessary to perform idle reading until the acquired data length becomes an integral multiple of the codeword. In this process, the process is performed using the cluster number and the value obtained in step S14 described above.

Next, it is judged whether or not the resync processing has been performed (step S16), and if the processing has not been performed (NO), the next row indicator is detected (step S18). However, when the resync processing is performed (YES), NG display (step S17)
Then, the process goes to step S18 to detect the next row indicator. Here, performing the resync process has a risk of lowering reliability because scanning is performed across rows. In order to prevent this, in step S16, the presence or absence of resync execution is detected and a warning is issued.

Then, in step S18, after detection of the next row indicator, v, y, z are calculated,
The reliability of the calculated v, y, z is obtained (step S1
9). These v, y, and z exist according to the rules in the row indicator. Therefore, it is calculated based on the information from the detected row indicators. Also,
Here, v is a value having the number of columns as a variable, y is a value having the number of rows as a variable, and z is a value having the error correction level and the number of rows as a variable.

It is judged whether or not this reliability is equal to or higher than a predetermined value (step S20). The reliability here means v, y, z
The calculated value of is read several times to determine whether the results are equal. If they are equal within a certain range, it is determined that the reliability is high. The predetermined value is an empirically set value.

If it is determined that the reliability is low (NO), the process returns to step S11 until the specified number of times (the number of retries) is reached, and the process is repeated until the reliability becomes the specified value ( Step S23). If the reliability does not reach the specified value even after repeating the specified number of retries and the process (YES), NG is displayed (step S2).
4) and the routine b is ended.

However, if it is determined in step S20 that the reliability is higher than the base value (YES), the number of columns, the number of rows, and the security level are calculated from v, y, and z described above ( Step S21).

Next, a necessary matrix is prepared from the number of columns, the number of rows, and the security level calculated in step S21 (step S22), and the process returns and returns to the routine of FIG.

Next, the matrix updating in step S6 of FIG. 4 will be described with reference to the flowcharts of FIGS. In this subroutine, the cluster number is calculated, the value is calculated, and the data in the matrix is updated.

First, the required number of scans is set based on the label size determined in step S3 of FIG. 4 (step S31). Based on the number of scans, the scan position of each row is set (step S32), and the number of scans of each row (how many scans per row) is set (step S33). In the second and subsequent scans, the center of each row is reset in step S32. Here, scanning means scanning in the horizontal direction (column direction) of the label.

Next, one line of the target image is extracted (step S34), and the data of this one line is Xs.
Convert from eq to T-seq (step S35). These X-seq and T-seq are as shown in FIG.
When the barcode is viewed as black and white repetitions, the width of each pattern (X-seq) and the width of the black and white pattern (T-
seq).

Next, the peak value for each codeword is obtained (step S36). For this peak value calculation, the peak value in each codeword is obtained from T-seq. Specifically, as shown in FIG. 10, consider black and white as one pair,
Find 7 levels of black and white (An, n = 1 to 7),
Take the average.

Next, after setting the absolute white level by the initial value setting (step S37), the PCS value (or bar width and radiant light conversion rate) is calculated (step S38). Specifically, as shown in FIG. 11, the ratio between the white level and the amplitude value of black and white is obtained, and the PCS value is determined using this ratio. Then, this value is output for each codeword (step S39).

Next, the start / stop code is detected (step S40). The bar code example shown in FIG. 3 includes unique start / stop codes. Therefore, it can be detected by comparing the start / stop patterns converted into T-seq.

Next, the peak values at the start / stop mark positions are measured (step S41). To measure the peak value, suppose that the start y coordinate of the start code 22 or the stop code 23 is the point p and the end y coordinate is the point q,
Differentiate the data from the point p to the point q. Then, the absolute value of the third peak of this differential data is set to the variable MAX,
This is the peak value.

Here, the reason why the third differential data is used as the peak value is that, empirically, the place where the contrast is the lowest in the bar code-code region, that is, the place where the edge differential peak is the lowest is set as the threshold value. The third edge with the smallest space between the label bar and the space is selected because it is desired. By this selection, stable decoding can be performed without being affected by the label size and label illumination conditions.

A peak value level (threshold value) is set based on the peak value (step S42). Based on the set threshold value, the level of the peak value obtained from the photographed barcode is determined (step S43).

When the peak value level is equal to or higher than the threshold value (YES) in this determination, the display of OK is displayed on the display unit 4 (step S45), and the process proceeds to step S46 of the next stage. However, when the peak value level has not reached the threshold value (NO), NG is displayed on the display unit 4 (step S44), and the series of processes is ended.

Next, in step S46, the cluster number and the value are obtained. Actually, the value is obtained by a calculation formula, and the table is referred to by the value. Next, the conditions for the resync processing are set (step S47). In actual decoding, scanning over rows may be considered, so it is better to loosely set the condition for moving to resync processing.

However, even if there are voids in the label, it is possible to judge that there is no problem as in the case of oblique scanning. Therefore, when performing label verification, it is better to set the conditions for resync to be stricter than in normal reading.

When the conditions for the resync processing are set,
Perform resync processing when crossing a line (step S
48). For example, when scanning across rows, eight pieces of X-seq data do not necessarily describe one codeword. Therefore, it is necessary to perform idle reading until the acquired data length becomes an integral multiple of the codeword. In this process, the process is performed using the cluster number and the value obtained in step S46 described above.

Then, it is determined whether or not the resync processing has been performed (step S49). If there is no resync processing in this determination (NO), the next row indicator is confirmed (step S50). However, when the resync process is performed (YES), NG is displayed on the display unit 4 (step S51), and the series of processes is ended.

When the resync processing is executed,
There is a risk that reliability will drop because scanning is performed across lines. To prevent this, step S
At 49, it is detected whether or not resync processing is performed, and a warning is given.

Next, in step S51, the row indicator is confirmed. To confirm this row indicator,
First, information on v, y, and z is obtained from the row indicator, and a row number is calculated based on the result.
Then, it is confirmed whether or not the line number and the position of the line for which the reliability is calculated at present or later are correct.

Next, the reliability of the value for one line is calculated (step S52). Actually, the reliability is obtained by referring to a table using three cluster numbers including oneself and both sides. Then, the line number of each value for one line is calculated (step S53). The calculation of the line number is performed in order to correctly input each value calculated for one line into the target line.

Next, the matrix is updated (step S5).
4). That is, the matrix is filled with the value for one line determined in steps S32 to S53. Until the target number set in step S31 has been processed, the process returns to step S32 and the same process is repeated (step S55).

After the processing of the set number is completed,
The reliability of each value of all matrices is output (step S56), and the process returns. The data in the matrix at this time point includes an erasure error described later.
It is possible to judge the quality of the label based on the output data of the reliability.

Next, the error correction in step S7 of FIG. 4 will be described with reference to the flowchart shown in FIG. First, using the matrix determined by the matrix update in step S6 of FIG. 4, the data in the matrix is converted into one-dimensional array data (step S61).

Then, one-dimensional array data having a certain reliability or lower is regarded as an erasure error (step S62).
Information indicating the erasure (codeword) position of the one-dimensional array data that has been determined to be an erasure error is prepared (step S63), and the number of erasure errors is output to a host computer or the like not shown.

Here, at the error correction level, 2
One type of error, the erasure error (era
Sure error) and error (Error). An erasure error is a state in which a codeword is missing or unreadable. In this case, the codeword position is known but the codeword value is unknown. On the other hand, an error is an erroneously encoded code, in which case neither the position nor the value of the codeword is known. From this fact, it is possible to distinguish and output the erasure error and the general error.

In this error correction processing, "code theory" (Hideki Imai, Corona Publishing Co.), ShuLin and DJ Coste
llo Jr: Error Control Coding, Fundamentals and App
lications, Prentice-Hall (1983), etc., and detailed description thereof is omitted here.

With respect to the erasure error, error correction processing is performed within a recoverable range. First, the syndrome polynomial S (x) is obtained (step S65). Then, the error locator polynomial λ (x) is calculated (step S6
6) This is differentiated (step S67). Further, the error evaluation formula Z (x) is obtained (step S68). The error value is determined by these equations (step S69).

Based on this error value, the data at the position causing the erasure error is updated (step S70), and the error-corrected data is put in the erasure error position. After that, verification is performed and the error correction result is confirmed (step S71). Then, the number of errors that cannot be corrected is counted and output to an external host or the like. (Step S72).

If the error can be corrected, the presence or absence of the error and the position thereof can be displayed by comparing the corrected data with the data including the erasure error before the correction. .

As described above, each output data determined by the information reading process, the tilt determination OK display, and the tilt determination N
G display, resync NG display (step S17), reliability NG display (step S24), peak display after each codeword (S36), peak value determination NG display (S4).
4), peak value judgment OK display (S46), resync NG
The display (S52), the reliability output of each value of all matrixes (S56), the erasure error number output (S64), and the error number output (S72) are selectively or simultaneously selected by the output selection unit 16 or the display unit 4 or the outside. Is output to the host computer or the like.

The reading process in the symbol information reading apparatus other than this embodiment is described in, for example, Japanese Patent Laid-Open No. 5-3
Even if it is adapted to the symbol information reading device described in Japanese Patent No. 24887, it is possible to achieve the verification of the stacked barcode targeted by the present invention.

As described above in the present embodiment, the symbol information reading device is provided with the function of outputting the results of various reading processes, so that the verification and reading can be performed reliably and quickly by one device. Can be done in.

Although the description has been made based on the above embodiment, the present invention also includes the following inventions. Image pickup means for picking up a barcode consisting of a bar and a space as a two-dimensional image, state detection means for detecting the image pickup state of the barcode from the two-dimensional image of the barcode obtained from the image pickup means, and state information by the state detection means And (1) a symbol information reading device for outputting information other than the original barcode information in a symbol information device comprising decoding means for decoding the original information from the two-dimensional image of the barcode.

(2) The symbol information reading device according to the above item (1), which is capable of sequentially outputting the read status information of the two-dimensional bar code. Therefore, the verification result (label quality) in the label verification can be seen at a glance for each codeword for the entire label.

(3) The symbol information reading device as described in the item (2), wherein the output bar code status information is a weighted value for each block of the bar code. Therefore, the weighted information can output the weighted information stored in the storage means in block units.

(4) The symbol information reading device as described in the above item (2), wherein the output bar code status information is a PCS value output for each code word. Accordingly, the PCS value can be obtained by the PCS value calculation means from the information stored in the storage means and the reference initial value, and output in block units.

(5) The output bar code status information is PCS
The symbol information reading device according to the item (2), which is a value determination signal. Therefore, the MAX value is determined by differentiating the read information, and by comparing this MAX value with the standard value, it is possible to judge whether the PCS value is proper or not.

(6) The symbol information reading device as described in the item (1), wherein the output barcode information is the number of barcode errors. Therefore, it is possible to clarify what is a problem in terms of quality from the verification result in the label verification.

(7) The symbol information reading device as described in the above item (6), wherein the output bar code status information is an error count number determined from a weight value for each block of the bar code.

Therefore, it is possible to output the error count number determined based on the weighted information. Since this function is intended to send out only the necessary data, only the desired data can be obtained and the transfer time to the host etc. can be reduced.

(8) The output bar code status information is the number of error counts that cannot be corrected when the error determined from the weighted value of each block of the bar code is corrected. Information reader.

Therefore, when the error in the above item (3) is error-corrected, the error count number that cannot be error-corrected can be output. (9) Item (3), item (4), item (5), item (7),
The barcode status information output obtained in item (8) is
The symbol information reader according to the item (1), which is selectively output.

(10) The symbol information reading device as described in the above item (1), which judges whether the width of the bar code is proper and outputs the judgment result. Therefore, it is possible to determine the appropriateness of the width information for each block by the width information determination unit for each block and output the determination result.

(11) Item (3), item (4), (5)
Item (1), which comprehensively determines the quality of the barcode based on the barcode status information obtained in items (7), (8), and (10), and outputs a determination signal. The described symbol information reading device.

Therefore, the above items (1), (2) and (3)
The output signals of the terms (4) and (6) are output simultaneously or selectively by the output switching means. (12) The symbol information reading device according to the above item (1), which is capable of setting conditions when performing the determination according to the above item (11).

[0078]

As described in detail above, according to the present invention, 2
Represents the quality status of the dimension bar code numerically, it is possible to provide symbol information reading apparatus capable of grasping the deteriorated state of the two-dimensional bar code.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a symbol information reading device as an embodiment according to the present invention.

FIG. 2 is a diagram showing a configuration example of a data processing unit shown in FIG.

FIG. 3 is a diagram showing a label structure example of a stacked barcode used in this embodiment.

FIG. 4 is a flowchart for explaining a schematic operation of the symbol information device according to the present embodiment.

FIG. 5 is a flowchart for explaining a subroutine of label size determination processing shown in FIG.

6 is a first half of a flowchart for explaining a subroutine of the matrix updating process shown in FIG.

7 is the second half of the flowchart for explaining the subroutine of the matrix updating process shown in FIG.

FIG. 8 is a flowchart for explaining a subroutine of the error correction processing shown in FIG.

FIG. 9: X-sequence and T-sequence
It is a figure for demonstrating e.

FIG. 10 is a diagram for explaining determination of a peak value for each codeword in FIGS. 6 and 7.

FIG. 11 is a diagram for explaining the PCS value calculation of FIGS. 6 and 7.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Two-dimensional image imaging part, 2 ... Data processing part, 3 ... Control part, 4 ... Display part, 5 ... Stacked bar code (bar code, bar code label), 6 ... Card, 7 ... Imaging lens, 8 ... Two-dimensional image pickup device, 9 ... Image processing unit, 11 ...
Bar code information memory, 12 ... Memory, 13 ... Read-out section, 14 ... Status detection section, 15 ... Decoding section, 16 ... Output selection section.

Claims (2)

(57) [Claims] 1. A two-dimensional image capturing means for capturing a two-dimensional barcode representing information as a two-dimensional image in which information is represented by a bar and a space, and the two-dimensional image from the two-dimensional barcode image obtained by the two-dimensional image capturing means. State detecting means for detecting the state of the barcode as a numerical value and comparing it with a predetermined threshold to detect the state of the two-dimensional barcode; and the two-dimensional barcode image captured by the two-dimensional image capturing means. Decoding means for decoding the original information into the original information, output selecting means for selectively outputting the information output from the status detecting means and the decoding means, and the status of the two-dimensional bar code selected by the output selecting means and a display means for displaying said status detection
The means determines the state of the two-dimensional bar code by the bar width and the radiation.
Emission conversion rate or output for each codeword
Weighting value for each block of 2D barcode,
Is the number of 2D barcode errors or 2D barcode
Error determined from the weighting value of each block
Count number or each block of 2D barcode
When the error determined from the weight value of is corrected
Any of the error counts that could not be corrected
Is detected as the numerical value and each threshold value corresponding to the type of the detected numerical value is stored.
A symbol information reading device having a storage means . 2. The state detecting means is configured to detect the detected secondary
Depending on the state of the original barcode, the two-dimensional barcode product
Even if it is possible to read it now,
Error occurs in reading the 2D barcode
If the quality is lower than the empirically determined quality,
A read error occurs on the display means via the output selection means.
The symbol information reading device according to claim 1, wherein a warning indicating that there is a possibility of life is displayed .