JPH09231298A - Recording medium bearing bar code and bar code reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record the information with high density by adding no identification mark pattern of a two-dimensional set itself nor a mark pattern that is formed by symbolizing the information on the two-dimensional set itself into this set of reflecting and non-reflecting surfaces with different optical reflection factors. SOLUTION: In regard to a bar code where a two-dimensional set or reflecting and a non-reflecting surfaces with different optical reflection factors suggests the information based on a prescribed rule, the two-dimensional set includes no recognition mark pattern of the set itself nor a mark pattern that is formed by symbolizing the information on the set itself. For instance, the bar code has a 4-row/3-column constitution consisting of a unit called code word 1 that includes a symbol length descriptor code word 2, a data code word 3 and an error correction code word 4. The word 2 shows the number of code words included in the bar code, the word 3 shows a part formed by encoding the data, and the word 4 detects the loss caused by the stains of the bar code, etc., and recovers the loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium on which a two-dimensional bar code capable of high density recording is displayed, and a bar code reader for decoding the bar code.

[0002]

2. Description of the Related Art Conventionally, various techniques have been developed for an optical reading device and an optical scanning device for reading a bar code symbol attached to the surface of a label or an article. The bar code symbol itself is a coded pattern of display consisting of a series of adjacent bars and spaces of varying width, with the bars and spaces having different reflective properties.

Further, in recent years, many two-dimensional bar code standards have been proposed due to the demand for high density bar code information. These standards include, for example, Code16K,
Code49, PDF417, Datacode, Ma
xicode etc. These two-dimensional bar codes can be roughly classified into the stacked type and the matrix type according to the code notation.

For example, Japanese Patent Laid-Open No. 3-204793 discloses a symbol notation method and a barcode reading method of PDF417 which is a typical stacked type two-dimensional barcode. That is, in this publication,
Each (n, k) type code has a 1-bit k-line (ie, k bars) and a 0-bit k-run (ie, k).
It is like stacking (17, 4) type one-dimensional bar code (stacked type) against the technology of expressing characters by a string of n bits including (spaces).
A technique for encoding / decoding a two-dimensional bar code of a format by introducing a method such as a two-step signal, cluster, scan stitching, and error correction is disclosed.

[0005]

However, in the above-mentioned prior art, when the scanner recognizes the barcode, it is usually necessary to use a redundant pattern that is unrelated to the information contained in the barcode. This is a pattern for clearly distinguishing the information around the barcode and the information about the barcode itself, and the pattern is determined by the barcode system.

Further, the above-mentioned two-dimensional bar code PDF41
In FIG. 7, in addition to such a redundant pattern, there is a pattern including the information of the barcode itself (the number of rows, the number of columns, the error correction level), but such a redundant component is one of the barcodes that have been desired in recent years. This is against the demand for higher density.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a recording medium on which a bar code is displayed for realizing high density recording of information as compared with PDF417, and the bar code. It is to provide a bar code reading method for reading.

[0008]

In order to achieve the above object, a recording medium in which a barcode according to the first aspect of the present invention is written has alternating reflective surfaces and non-reflective surfaces with different optical reflectances. A recording medium having a bar code in accordance with a bar code notation in which a plurality of mark patterns are arranged such that the two-dimensional set of the reflective surface and the non-reflective surface has information according to a predetermined rule. It is characterized in that the two-dimensional set does not include a characteristic mark pattern for recognizing the set itself and a mark pattern obtained by encoding information about the set itself.

In the bar code reading method according to the second aspect, the reflective surface and the non-reflective surface having different optical reflectances are alternately arranged, and the two-dimensional set of the reflective surface and the non-reflective surface follows a predetermined rule. A plurality of mark patterns are arranged so as to suggest information, and a plurality of codeword rows formed by the mark patterns are adjacent to each other in the vertical direction,
Each codeword row is composed of a codeword, each codeword corresponds to character information determined by the configuration of each width of the mark pattern, and each codeword row has a different characteristic for each row. A bar code for identifying adjacent lines together with each other, and not including a codeword that encodes information about the characteristic pattern and the symbol itself in each codeword line to recognize the symbol notation itself. Is a bar code reading method for reading a bar code from a recording medium in which the code word line is sequentially scanned by a relative position change with a symbol written in the recording medium, and a line number of the code word line. Is determined for each row using a different feature, and the result of decoding the above codeword row for each scan is an array stored in advance in a volatile storage medium. And wherein the storing.

Furthermore, the bar code reading method according to the third aspect includes mark patterns having different optical reflectances, each mark pattern having alternating reflective surfaces and non-reflective surfaces. A plurality of codeword rows to be written are vertically adjacent to each other, each codeword row is composed of codewords, and each codeword corresponds to character information determined by the configuration of the width of each mark pattern. Each codeword line has a different feature for each line, it is possible to identify adjacent lines, and each codeword line has a characteristic required for recognizing the symbolic notation itself. What is claimed is: 1. A bar code reading method for decoding a symbol, which includes at least one codeword that encodes information about a pattern and a symbol itself. If at least one of the codeword that encodes the characteristic pattern necessary for recognizing the symbolic notation itself included in the code line and the information about the symbol itself cannot be decoded, the line number of the above codeword line is set. It is characterized in that each row is determined by using a different feature, and the result of decoding the codeword row is stored for each scan in an array previously stored in a volatile storage medium.

That is, in the recording medium in which the bar code is written according to the first aspect of the present invention, the reflective surface and the non-reflective surface having different optical reflectances are alternately arranged, and the two reflective surface and the non-reflective surface are provided. A bar code is represented by a bar code notation method in which a plurality of mark patterns are arranged so that the dimension set suggests information according to a predetermined rule, and the two-dimensional set has a characteristic mark for recognizing the set itself. The pattern and the mark pattern that symbolizes the information about the set itself are not included.

In the bar code reading method according to the second aspect, the codeword rows are sequentially scanned due to the relative position change with respect to the symbols written on the recording medium, and the row numbers of the codeword rows are line by row. The result of decoding the codeword row for each scan, determined using different features, is stored in a pre-stored array on the volatile storage medium.

Further, in the bar code reading method according to the third aspect, the characteristic pattern necessary for recognizing the symbol notation itself included in the specific code word row and the information about the symbol itself are coded in a small number. If either one cannot be decoded, the row number of the codeword row is determined using a different feature for each row, and the result of decoding the codeword row for each scan is stored in advance in a volatile storage medium. Stored in the array.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A shows the structure of a recording medium in which the barcode of the present invention is written and described. In this figure, in this example, the barcode has a configuration of 4 rows and 3 columns, and is configured with a unit called a codeword 1 as a reference. Each codeword 1 is composed of a bar and a space. In the present invention, the barcode of such a system is attached to a recording medium such as paper or a label.

The detailed construction of the bar code is shown in FIG. 1B and will be described. As shown in the figure, the bar code includes a symbol length descriptor codeword 2, a data codeword 3 and an error correction codeword 4.

The symbol length descriptor codeword 2 is
It represents the number of codewords included in the barcode. This is the number of codewords including the symbol length descriptor codeword 2 itself. The data codeword 3 is a portion in which data transmitted as information is encoded. The error correction codeword 4 is, for example, Lin, Costello Jr.
Co-authored `` Error Control Coding Fundamentals and Applic
ations ", Prentice-Hall (1983), and is a codeword for detecting and recovering the loss of the codeword due to stains on the barcode.

Next, the codeword 1 will be described in detail with reference to FIG. This barcode is (17,
4) Type 5 code, so bar 5 and space 6
There are four each, and each width is a unit of code (that is, "x
It is an integer multiple of the specified minimum width, referred to as a "dimension" or "module"). The width of one codeword is 17 units, and the maximum unit of each bar and space is 6 units.
It is.

At the right end of FIG. 1, there is a bar having a width of 1 unit which is not related to a codeword, but this is necessary because of the nature of the codeword starting with a bar and ending with a space, so-called stop mark ( Stop code) is different.

The method of decoding the codeword 1 will be described in detail below. First, the width information of each bar and space is extracted from the codeword 1 to form a total of eight numeric strings. This is called the x series. In the example shown in FIG. 2, the x-series is “2, 1, 3, 2, 2, 5, 1, 1”.

Next, each adjacent x-series is added to form a total of seven numerical sequences. This is called a t series.
In the example of FIG. 2, the t series is “3, 4, 5, 4, 7,
6, 2 ”. The maximum value of each value of this t series is 9. Further, the t series has a function of alleviating the phenomenon that the bar becomes thick and the space becomes thin due to the diffusion of the printer ink by the printing of the bar code.

A predetermined look-up table is referred to by using this t series and a cluster described later, and a value between 0 and 928 is converted. This value is called a codeword value.
This process corresponds to the low-level decoding of the two-step decoding described later.

The cluster will be described in detail with reference to FIG. According to the description method of programming language C,
Assuming that the t series is stored in the array from t [0] to t [6], the cluster of each codeword is calculated by the following equation.

Cluster = (t [0] -t [1] + t [4] -t
[5] +9) mod9 Here, mod represents a remainder expression, for example, 5 mod3 = 2.
Becomes In the code system of the present invention, the cluster of every codeword included in the barcode becomes 0, 3 or 6. That is, when the values of the other clusters are obtained by the calculation of the above equation, it can be considered that some misreading has occurred.

For example, in the codeword example of FIG. 2, (3
-4 + 7-6 + 9) mod9 = 0, that is, 0 clusters. Further, as shown in FIG. 3, by unifying the clusters of codewords in each line of the barcode and alternately using different clusters for each line, it is possible to clearly distinguish between lines that are in contact with each other vertically. You can

Next, the two-step decoding will be described in detail.
Two-stage decoding consists of low-level decoding and high-level decoding. As described above, each codeword is converted from its t series and cluster into a codeword value between 0 and 928 by a predetermined look-up table. This corresponds to low level decoding.

Codeword values between 900 and 928 are used to represent special control codes other than normal information. Therefore, normal information is assigned to codeword values 0 to 899.

Here, it is considered that the codeword value is decomposed by the radix 30. That is, VH = xdiv30 and VL = xmod30. Here, x is a codeword value, VH and VL are values after decomposition, and div is a division formula. For example, 5
When the codeword value of 20 is decomposed, 520 = 17 ×
Since 30 + 10, VH = 17 and VL = 10.

And these two values (17 and 10)
Is converted into the corresponding character by searching the table as shown in FIG. The table illustrated in FIG. 4 shows 30 decoding modes including alpha, subordinate, mixed, and punctuation modes. In this example,
Alpha mode is the default mode. Therefore, the t-sequences 3, 4, 5, 4, 7, 6, 2, of the samples are
Finally, the codeword value 520 and the radix 30 number sequence 1
It will be converted into a two character string RK through steps 7 and 10.

The high level decoding process according to the present invention will now be described with reference to the state transition diagram of FIG. Arrows in the figure represent movement between modes. In the figure, "a1" is an alpha latch, "ll" is a lower latch, "ml" is a mixed latch, "pl" is a punctuation latch,
“As” indicates an alpha shift, and “ps” indicates a punctuation shift. The latch indicated by the solid arrow in the figure is
The mode continues to stay until the next movement instruction is given, and the shift indicated by the broken line arrow in the figure moves the mode by the next one character. Here, as an example, it is assumed that the decoder is currently in alpha mode.

To change from the alpha mode to the mixed mode as shown in FIG. 3, the V of a sequence of two digits and thirty bases is used.
Either H or VL must equal 28.
In alpha mode, the 28 VH signals the decoder to switch to mixed mode ("ml" in Figure 5).
That is, shown as a mixed mode latch). Therefore, VL of the VH and VL pairs will be interpreted in mixed mode. At VL of 28, the decoder interprets the VH of the VH.VL pair in the current mode (ie, alpha mode) and then switches to mixed mode.

Regarding error correction, the above-mentioned Japanese Patent Laid-Open No. 3-2
04793 and Lin, Costello Jr, "Error Cont
rol Coding Fundamentals and Applications '', Prenti
Since it is described in ce-Hall (1983), the explanation is omitted here.

Next, the barcode reading method of the present invention will be described in detail. FIG. 6 is a diagram showing the configuration of an apparatus that realizes the barcode reading method of the present invention. As shown in the same figure, this device includes an imaging lens 12 and a one-dimensional imaging device 1.
4 and a data processing device 15. Data processing device 1
Reference numeral 5 is composed of a CPU, a memory and the like (not shown), and performs various operations for decoding the barcode information. Further, the memory in the data processing device 15 is configured with various registers for storing various constants and variables as described later.

In such a structure, the bar code label 11 having the above-mentioned format is used for the imaging lens 1.
2 forms an image on the photoelectric conversion surface 13 mounted on the one-dimensional image pickup device 14. The label information photoelectrically converted by the one-dimensional imaging device 14 is taken into a memory in the data processing device 15 as a video signal. At this time, the relative position of the one-dimensional image pickup device 14 and the barcode label 11 changes, so that the one-dimensional image pickup signal is sequentially transferred to the memory, and the reading process described later is performed each time.
In FIG. 6, the position of the one-dimensional image pickup device 14 is fixed, and the barcode label 11 is shown to move. The bar code label 11 has the code shown in FIG. 1 described above. Data processing device 1
In 5, the barcode information is decoded based on an algorithm described later and output to a host device (not shown) or the like.

FIG. 7 shows the configuration of an improved example of the apparatus shown in FIG. 6 and will be described. As shown in the figure, this device has a configuration in which a host computer 24 and a card reader 21 are connected by a cable 25, an LED 23 is provided on the card reader 21, and a bar code label 1 is further provided. An insertion port 22 for inserting the card 20 marked with is provided.

In such a structure, when the operator inserts the card 20 into the insertion slot 22 of the card reader 21,
The contents of the barcode label 1 are read and the information of the barcode label 1 is transferred to the host computer 24 or a terminal device (not shown). LED 23 of the card reader 21
Indicates the operating state of the card reader 21.

As described above, in this improved example, the barcode label 1 is automatically set, so that the barcode label 1 is not relatively displaced, so that highly accurate reading is realized.

Hereinafter, referring to the flow chart of FIG.
An algorithm for decoding the barcode information by the data processing device 15 will be described. The following description will follow the description method of the programming language C.

First, various parameters such as threshold values and various global variables are initialized (step S1), and an image capturing routine is called to capture a one-dimensional image in the memory of the data processing device 15 (step S2). .

Next, a subroutine "width information conversion and width number counting" which will be described in detail later is called to convert the image pickup signal in the one-dimensional image into width information and count the number of widths (step S3). Then, it is determined whether or not the result of counting the number of widths in step S3 is equal to or more than a threshold value (step S4). If the number of widths is less than the threshold value, the above step is repeated. The control is transferred to S2, and the image capturing routine is called to capture the next one-dimensional image.

On the other hand, in step S3, if the number of widths is greater than or equal to the threshold value, a subroutine "barcode tilt detection", which will be described in detail later, is called to tilt the bar code label to the left or right. It is determined whether or not (step S5). Then, the codeword income processing routine is called (step S6), and the cluster and the codeword value are obtained from the width information obtained in step S3 by the method described above.

Subsequently, it is determined whether or not a valid codeword is obtained as a result of the codeword income processing in step S6 (step S7). If no valid codeword is obtained, Returns the control to step S2 again to call the image capturing routine.

On the other hand, if a valid codeword is obtained in step S7, the subroutine "line calculation" is executed.
Is called (step S8) to calculate which line of the barcode label the width information of the captured one-dimensional image corresponds to. Next, the subroutine "matrix processing" is called (step S9), and the converted codeword value is stored in the memory portion corresponding to the appropriate row and column.

Next, it is judged whether or not the bar code can be decoded based on the information up to this point (step S10). If not, the control is transferred to the above step S2 again to call the image capturing routine. On the other hand, if possible,
The high-level decoding process described above is performed (step S11),
Quit the program.

The various processing routines will be described in detail below. First, the sequence of the subroutine "width information conversion and width number counting" called in step S3 will be described with reference to the flowchart of FIG. 9 and the drawing for explaining the width information conversion. This subroutine is a process for converting the binarized image pickup information fetched in the memory into a numerical sequence of width values. That is, the process of converting the bar and space 31 shown in FIG. 10 into the width information 33 is performed. The CCD image pickup information 32 in FIG. 10 represents the height of the received light voltage.

In this routine, first, the variables i, widt are
The h _- num and the two-dimensional array width are initialized (step S21). Here, the variable scan _-- num is the number of samples of image information, which is determined by the number of CCD elements. It is also assumed that the sample output from the image capturing routine is stored in the array scan and has already been binarized. Next, it is determined whether the sample of the array scan [0] is 0 or 1 (step S
22).

Here, if it is 1, 1 is assigned to the variable flag (step S23), and if not, the variable flag is set.
0 is substituted for (step S24). Then the variable flag
It is determined whether is 1 (step S25),
If 1, go to step S26, otherwise go to step S27.

In step S26, it is determined whether the array scan [i] is 1, and if it is 1, the array wid
Increment th [width _- num] (step S28). Otherwise, the variable flag is set to 0 and the variable width _-- num is incremented (step S29).

In step S27, it is determined whether the array scan [i] is 0, and if it is 0, the array wid
Increment th [width _- num] (step S30). Otherwise, the variable flag is set to 1 and the variable width _-- num is incremented (step S31).

Next, the variable i is incremented (step S32), and the variable i is changed to the variable scan.
_{-Num is determined whether or not (step S
33). If so,} the value of the _{variable width -} num is returned to the higher-level function, and if it is not likely to return to the higher-level function, the control is transferred again to the step S25 to judge the variable flag.

Next, the sequence of the subroutine "bar code tilt detection" called in step S5 will be described with reference to the flowchart of FIG. 11 and the bar code tilt detection diagram of FIG. This routine detects whether the bar code is tilted left or right from the relative angle formed by the linear sensor and the bar code.

First, it is judged whether or not the variable titt _- flag initialized to 0 in the initialization routine of step S1 is 0 (step S41). And til
If the t _- flag is 0, the tilt _- flag is set to 1 (step S42).

In the above step S42, tilt _-- fl
If ag is 1, the process returns to the higher-level function. These two steps are necessary in the entire bar code decoding process in order to detect the inclination of only the first line of data.

Then, it is determined whether or not the width information array width [0] determined by the width information conversion and width number counting routine is larger than a preset threshold value (step S43). As shown in FIG. 12, wid
th [0] is a margin part, and the threshold is, for example, CCD
Set to half the number of elements in. Here, if it is larger than the threshold value, 1 is assigned to the variable left _-- flag (step S44), and if it is smaller than the threshold value, the variable left.
Substitute 0 for t _- flag (step S45) and return to the higher-level function.

Next, referring to the flow chart of FIG. 13, the subroutine "row calculation" called in step S8 is executed.
Will be described. This routine is to calculate which line of the codeword the codeword value obtained in step S6 is, by using the concept of cluster and row block.

First, the variables col and left _-- pro _-- fl
0 is substituted for ag, right _- pro _- flag and initialized (step S51). Where the variable left _-- pr
o _- flag and right _- pro _- flag are variables used in a routine of a subroutine "bar code inclination processing" described later.

[0056] Next, the address col _- a number that is stored in the index and assign it to a variable cluster, col _-
The index is incremented (step S52).
Here, it is assumed that the address col _- index is set in the codeword income process of step S6.

Next, the value of the variable cluster is 0,
It is determined whether or not other than 3 and 6 (step S5
3). If so, the process proceeds to step S61, and if not, it is determined whether the variable cluster is 0 (step S54). Here, if 0, the variable change _- f
It is determined whether lag is 1 (step S55).

Here, it is assumed that the variable change _-- flag is initialized to 0 in the initialization routine of step S1. If not 0, it is determined whether cluster is 6 (step S56).

If the result of the determination in step S55 is true, the variable row _-- block is incremented, 0 is assigned to the variable scan _-- num, and the variable change _-- fl.
Substitute 0 for ag (step S57). Here, it is assumed that the variables row _-- block and scan _-- num have been initialized to 0 in the initialization routine of step S1.

On the other hand, if the result of the determination in step S55 is false, the process proceeds to step S59. If the result of the determination in step S56 is true, the variable change _-- flag is set to 1
Is substituted (step S58). If false, step S
Go to 59.

The concept of row blocks is introduced in the series of processes from steps S54 to S58. Referring to FIG. 3, the notation code clusters are 0, 3,
It takes a value of 6 and has a row configuration in which 3 clusters are alternately repeated. This cluster 0, 3,
The 3 rows of 6 are defined as a 1-row block. Therefore, when the cluster 6 is first recognized, a flag is set, and when the cluster 0 is recognized the next time this row calculation routine is called while the flag is set, the row block is updated. To S58. Here, the update of the row block is performed focusing on only one arbitrary column.

Then, the calculation result of row _- block * 3 + cluster / 3 is substituted into the array row _- num [col]. For example, if row _- block is 5,
If the codeword cluster is 6, then 5 * 3 + 6/3
= 17, it can be seen that the line is the 17th line (however, the line starts from 0). Next, the barcode inclination processing routine is called (step S60).

This is because the bar code has an angle relative to the linear sensor as shown in FIG.
If the data is fetched across two row blocks, the row block is updated with the code word in the first column, and then the code word in the third column is simply calculated in step S59. Since it is recognized as the cluster 6 and the accurate line number cannot be obtained, the bar code inclination processing routine of step S60 is called to adjust the line.

Then, the variable col is incremented (step S61), and it is determined whether col is greater than or equal to the constant COL _-- NUM (step S62). If it is determined that the above, go to step S63, otherwise, again,
The control is moved to the step S52. Where the constant COL
_- NUM is the number of columns of the bar code set by the initialization routine of step S1.

Next, the variable scan _-- num is incremented (step S63), and it is determined whether or not it is larger than a preset threshold value (step S64). If it is larger, increment the variable row _- block,
Variable scan _- 0 is assigned to num, variable change _-
Substitute 0 for flag (step S65). Otherwise, it returns to the higher-level function.

In the series of processing from steps S63 to S65, if the cluster cannot be recognized due to the influence of dirt on the bar code and the row block is not updated accordingly, the cluster is recognized. It realizes the update of a non-row block. Therefore, the threshold value is preferably set to the number of times the line calculation routine is called before the bar code moves by one line block.

Next, referring to the flowchart of FIG.
The sequence of the subroutine "bar code inclination process" called in step S60 will be described. This routine is a routine for accurately recognizing the line number of the codeword when the barcode is tilted as shown in FIG. 14 and the image pickup information is acquired over two line blocks. In addition, here, the inclination of the barcode is as shown in FIG.
It is assumed that the captured image information to be captured does not extend over three lines or more as shown in FIG.

First, it is determined whether the variable left _-- flag is 1 (step S71). This left _-
The flag is a variable determined by the barcode inclination detection routine of step S5. If this is 1, the barcode is inclined to the left.

[0069] In the step S71, variable left _-
If the flag is 1, then it is determined whether or not the variable col is 0 (step S72). This col is a variable prepared in step S8 and indicates a column number.

When the variable col is 0 in step 72, it is determined whether the variable cluster is 6 (step S73). If it is not 0, it is determined whether the variable cluster is 0 (step S74). On the other hand, in the step S73, the variable clus
If ter is 6, 1 is substituted into the variable left _-- pro _-- flag (step S75). This left _- pr
o _- flag is a variable initialized at the beginning of the row calculation routine in step S8. If not 6, it returns to the higher-level function.

In step S74, the variable cluster
If is 0, 1 is substituted into the variable left _- pro _- flag (step S76). If it is not 0, it returns to the higher-level function. In step S76, the variable left _-- p
If ro _- flag is 1, then the array row _- num [co
3] is added to [l] (step S77). This is a process of correcting the influence of erroneous recognition of row blocks. If the variable left _- pro _- flag is not 1, the process returns to the higher-level function.

The series of processes from step S72 to step S77 described above is a correction process when the bar code is tilted to the left. That is, the case is the opposite of the example of FIG. Next, the case where the barcode is tilted to the right will be described.

In step S71, the variable left _-- fl is set.
If it is determined that ag is 0, it is determined whether the variable col is 0 (step S78). Where the variable co
If l is 0, it is determined whether the variable cluster is 0 (step S79). And the variable co
If l is not 0, it is determined whether the variable cluster is 6 (step S80). If the variable cluster is 0 in step S79, the variable right
_- pro - 1 is substituted for the flag (step S81).
If it is not 0, it returns to the higher-level function.

In step S80, the variable cluster
Is 6, the variable right _-- pro _-- flag is 1
Is determined (step S82). Variable cl
If the user is not 6, the process returns to the higher-level function. If the variable right _-- pro _-- flag is 1 in step S82, 3 is subtracted from the array row _-- num [col] (step S83). If it is not 1, it returns to the higher-level function.

By performing the series of processes from step S83 to S85 described above, it is possible to correct the erroneous recognition of the line number when the bar code is tilted to the right as shown in FIG.

Next, referring to the flowchart of FIG.
The routine of the subroutine "matrix processing" called in step S9 will be described. This routine is to embed a codeword value in a two-dimensional array prepared in advance based on the row information calculated by the row calculation routine in step S8.

First, 0 is assigned to the variable col for initialization (step S90), and the value of the row information array row _-- num [col] calculated in step S8 is assigned to the variable row (step S91). Next, two-dimensional array cwma
The variable value is assigned to trix [row] [col] (step S92). Here, the codeword value determined in step S6 is stored in value. Next, the variable col is incremented (step S9
3), it is determined whether col is larger than a constant COL _- NUM (step S94). If it is larger, the process returns to the higher-level function, and if it is smaller, the control is moved to the step S91 again.

Next, a second embodiment will be described.
In this embodiment, when the start / stop code and the row indicator cannot be read when reading the normal PDF417 two-dimensional bar code, the above method is used as the auxiliary decoding means to enable reading.

In the present embodiment, mark patterns having different optical reflectances are included, each mark pattern has a reflective surface and a non-reflective surface alternately, and a two-dimensional set of each mark pattern has information according to a specific rule. Characterized in that it encloses a characteristic mark pattern necessary for recognizing the set itself in a two-dimensional set of the mark patterns and a mark pattern that encodes information about the set itself. A barcode reading method for decoding a symbol represented by the symbol notation is realized.

At least a characteristic mark pattern necessary for recognizing the set itself in the two-dimensional set of each mark pattern due to the influence of voids, spots, etc. and a mark pattern encoding information about the set itself are at least It is characterized in that the two-dimensional set of each mark pattern is decoded even if one cannot be read.

The sequence of this embodiment will be described in detail below with reference to the flowchart of FIG. First, various parameters such as threshold values and various global variables are initialized (step S101), and the image capturing routine is called to capture a one-dimensional image in the memory of the data processing device 15 (step S102).

Next, the width information conversion converts the image pickup signal in the one-dimensional image into width information (step S103).
Then, it is determined whether or not the start / stop code and the row indicator are present (step S104),
If these codes are present, the normal PDF417 reading process is performed (step S105), it is determined whether the data code is possible (step S106), and if the data cannot be decoded, the process returns to step S102. If possible, high-level signal processing is performed (step S107), and the operation ends.

In step S104, if the start / stop code and the row indicator do not exist, the subroutine "codeword income processing" is called (step S108), and the above-mentioned method is performed from the width information obtained in step S103. To get the cluster and codeword value. Subsequently, it is determined whether or not a valid codeword is obtained as a result of the above codeword income processing (step S
109) If no valid codeword is obtained, the control is transferred again to step S102 to call the image capturing routine.

On the other hand, if a valid codeword is obtained in step S109, the line calculation routine is called (step S110), and the width information of the fetched one-dimensional image indicates the number of lines of the bar code label. Calculate whether it corresponds to eye information. Then, the matrix processing routine is called (step S111), and the converted codeword value is stored in the memory portion corresponding to the appropriate row and column.
Then, the process proceeds to step S106, the same processing as above is performed, and the operation is ended.

As described above, in this embodiment, the PDF
If the 417 start / stop code or row indicator cannot be read, the function is programmed to be called and decoded.

In the above description, the symbol notation from which the start / stop codes and the left and right row indicators have been removed from the PDF417 has been shown.
It goes without saying that the symbol notation excluding the stop code and the symbol notation excluding the left and right row indicators from the PDF 417 are also possible.

As described above, the present invention provides a recording medium in which a barcode having a high density without a redundant component is shown, and a barcode reading method for reading the barcode, which can be used for various physical distribution and others. In applications, the limited surface area of an object can be effectively used to carry information.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various improvements and changes can be made without departing from the spirit of the present invention. For example, the one-dimensional imaging device 14 may scan using a laser device instead of the linear CCD. Of course, it is also possible to replace the one-dimensional imaging device 14 with a two-dimensional imaging device and perform appropriate processing.

According to the above embodiment of the present invention, the following inventions are also included. (1) The reflective surface and the non-reflective surface having different optical reflectances are alternately arranged, and a plurality of mark patterns are arranged so that the two-dimensional set of the reflective surface and the non-reflective surface suggests information according to a predetermined rule. In the recording medium in which a barcode is written by the barcode notation method, a characteristic mark pattern for recognizing the set itself and a mark pattern obtained by encoding information about the set itself are added to the two-dimensional set. A recording medium on which a bar code is written that is not included. (2) In the bar code, a plurality of codeword rows composed of the mark patterns are vertically adjacent to each other, the codeword rows are composed of codewords, and the codewords are composed of the codewords. Corresponding to character information determined by the configuration of the width of the mark pattern, each codeword line has a different characteristic for each line and is distinguished from the adjacent line, and the code notation itself is recognized in each codeword line. The recording medium on which the barcode is written according to claim 1, wherein the recording medium does not include a characteristic pattern for doing so and a codeword that encodes information about the symbol itself. (3) The above-mentioned barcode is a two-dimensional barcode system PDF417, and the PDF417 is added to the codeword line.
Characteristic patterns and PDs required to recognize oneself
The recording medium having the bar code according to claim 1, wherein the recording medium does not include a codeword that encodes information about the F417 itself. (4) The recording medium on which the barcode is written according to claim 3, wherein the barcode is a PDF417 which is a two-dimensional barcode system from which start / stop marks and row indicators are removed. (5) The recording medium in which the barcode is written according to claim 3, wherein the barcode is a two-dimensional barcode system PDF417 from which a start mark and a stop mark are removed. (6) The recording medium described in claim 3, wherein the bar code is a two-dimensional bar code system PDF417 excluding the row indicator. (7) A reflective surface and a non-reflective surface having different optical reflectances are alternately arranged, and a plurality of mark patterns are arranged so that the two-dimensional set of the reflective surface and the non-reflective surface suggests information according to a predetermined rule. A plurality of codeword rows formed by the mark patterns are adjacent to each other in the vertical direction, the codeword rows are formed by codewords, and the codewords have the widths of the mark patterns. Corresponding to the character information determined by the above, each of the codeword lines has a different feature for each line and identifies adjacent lines, and each of the codeword lines has a characteristic for recognizing the symbolic notation itself. A bar code from a recording medium on which a bar code is written, which does not include a code word that encodes information related to various patterns and the mark itself. A method of reading a barcode, wherein codeword rows are sequentially scanned by a relative position change with respect to a symbol written on the recording medium, and the row number of the codeword row is determined using a different feature for each row. A method of reading a barcode, wherein the result of decoding the codeword row is stored for each scan in an array prestored in a volatile storage medium. (8) The barcode reading method according to claim 7, wherein the feature different for each row is a cluster of PDF417, which is a two-dimensional barcode system. (9) Reflective and non-reflective surfaces having different optical reflectances are alternately arranged, and a plurality of mark patterns are arranged so that the two-dimensional set of the reflective and non-reflective surfaces suggests information according to a predetermined rule. A plurality of codeword rows composed of the mark pattern are adjacent in the vertical direction, each codeword row is composed of a codeword,
Each of the codewords corresponds to character information determined by the configuration of each width of the mark pattern, each codeword row has a different characteristic for each row, and identifies adjacent rows. Bar code reading that reads a bar code from a recording medium on which a bar code is written, characterized in that the word line does not include a characteristic pattern for recognizing the symbol notation itself and a code word that encodes information about the symbol itself A method, in which codeword rows are sequentially scanned by a relative position change with respect to a symbol written on the recording medium, and the row number of the codeword row is determined using a different feature for each row. The relative angle between the symbol and the scanning device is detected, the line number of the codeword line is determined using the information on the relative angle, and the line number is determined for each scan. Bar code reading method characterized by storing the results of decoding the quadword line to previously stored sequence in the volatile storage medium. (10) The barcode reading method according to claim 9, wherein the feature different for each row is a cluster of PDF417, which is a two-dimensional barcode system. (11) A mark pattern having different optical reflectance is included, each mark pattern has a reflective surface and a non-reflective surface alternately, and a plurality of codeword rows described by each mark pattern are vertically adjacent to each other. Each codeword line is composed of codewords, each codeword corresponds to the character information determined by the configuration of the width of each mark pattern, and each codeword line is different for each line. A codeword that has a characteristic and is capable of identifying adjacent rows, and encodes information about the characteristic pattern and the symbol itself necessary for recognizing the symbolic representation itself in each codeword line. A barcode reading method for decoding a symbol including at least one of, and a feature necessary for recognizing the symbol notation itself included in a specific codeword line. If at least one of the codewords encoding the information about the pattern and the symbol itself could not be decoded, the line number of the codeword line is determined using different features for each line, and the code is determined for each scan. A method of reading a bar code, characterized in that the result of decoding a word row is stored in an array previously stored in a volatile storage medium. (12) The above symbols are PDF41 of the two-dimensional barcode system.
12. The bar code reading method according to claim 11, wherein the characteristic is 7 and the feature that differs for each row is a cluster.

[0090]

According to the present invention, it is possible to provide a recording medium on which a barcode is displayed, which realizes high density recording of information as compared with PDF417, and a barcode reading method for reading the barcode.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a recording medium in which a barcode of the present invention is written.

FIG. 2 is a diagram for explaining the codeword 1 in detail.

FIG. 3 is a diagram for explaining the line configuration of the code in FIG. 1 in detail using clusters.

FIG. 4 is a diagram showing an example of a correspondence table required for a high level signal.

5 is a diagram showing a state transition diagram according to a feature of the method using the table of FIG.

FIG. 6 is a diagram showing a configuration of a barcode reading apparatus that realizes a barcode reading method of the present invention.

7 is a diagram showing a configuration of an improved example of the barcode reading device in FIG.

8 is a flowchart showing an algorithm for decoding barcode information in the data processing device 15. FIG.

[Fig. 9] Subroutine "width information conversion and width count"
3 is a flowchart showing the sequence of FIG.

FIG. 10 is a diagram for explaining width information conversion for converting imaging information of bars and spaces into width information.

FIG. 11 is a flowchart showing a sequence of a subroutine “bar code inclination detection”.

FIG. 12 is a diagram for explaining a method for detecting the left / right inclination of a barcode.

FIG. 13 is a flowchart showing a sequence of a subroutine “row calculation”.

FIG. 14 is a diagram showing how data is fetched across a data block of a barcode.

FIG. 15 is a flowchart showing a sequence of a subroutine “bar code inclination processing”.

FIG. 16 is a flowchart showing a sequence of a subroutine “matrix processing”.

FIG. 17 is a flowchart for explaining in detail the barcode reading method according to the second embodiment.

[Explanation of symbols]

 1 Codeword 2 Symbol Length Descriptor Codeword 3 Data Codeword 4 Error Correction Codeword 5 Bar 6 Space 11 Barcode Label 12 Imaging Lens 13 Photoelectric Conversion Surface 14 One-dimensional Imaging Device 15 Data Processing Device

Claims (3)

[Claims] 1. A reflective surface and a non-reflective surface having different optical reflectances are alternately arranged, and a plurality of mark patterns are provided so that a two-dimensional set of the reflective surface and the non-reflective surface suggests information according to a predetermined rule. A recording medium in which a bar code is written according to a bar code notation to be arranged, wherein a characteristic mark pattern for recognizing the set itself and a mark pattern in which information about the set itself is symbolized in the two-dimensional set. A recording medium on which a barcode is written, which does not include and. 2. A plurality of mark patterns are provided such that reflective surfaces and non-reflective surfaces having different optical reflectances are alternately arranged, and a two-dimensional set of the reflective surface and the non-reflective surface suggests information according to a predetermined rule. A plurality of codeword rows arranged by the mark patterns are vertically adjacent to each other, each codeword row is composed of codewords, and each codeword has each width of the mark pattern. Corresponding to the character information determined by the configuration, each codeword line has a different characteristic for each line and identifies adjacent lines, for identifying the code notation itself in each codeword line The barcode is recorded from a recording medium on which a barcode characterized by not including a codeword that encodes information about the characteristic pattern and the symbol itself is included. A bar code reading method for reading, in which code word lines are sequentially scanned according to a relative position change with respect to a symbol written on the recording medium, and a line number of the code word line is determined using a different feature for each line. Then, the bar code reading method is characterized in that the result of decoding the code word row is stored for each scan in an array previously stored in a volatile storage medium. 3. A mark pattern having different optical reflectance is included, each mark pattern has a reflective surface and a non-reflective surface alternately, and a plurality of codeword rows described by each mark pattern are arranged in the vertical direction. Adjacent to each other, each codeword line is composed of codewords, each codeword corresponds to character information determined by the configuration of the width of each mark pattern, each codeword line is line by line. It is possible to discriminate adjacent rows having different characteristics, and each of the above codeword rows is encoded with a characteristic pattern necessary for recognizing the symbolic notation itself and information about the symbol itself. A barcode reading method for decoding a symbol including at least one codeword, which is necessary for recognizing the symbol notation itself included in a specific codeword line. If at least one of the codewords encoding the characteristic pattern and the information about the symbol itself could not be decoded, the row number of the codeword row is determined using different characteristics for each row, and for each scan. A method of reading a bar code, characterized in that the result of decoding the code word row is stored in an array stored in advance in a volatile storage medium.