JPS6356587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information code reading device for a label reader device that optically scans a barcode to read the information code in the barcode.

Conventional information code reading devices for label reader devices sequentially detect each digit of the information code and each pulse width array of the stop code from the start code of the scanned barcode, and simultaneously decode all information of the barcode for each scan. There is something I tried to do. However, in such a configuration,
If a barcode symbol has a defect such as dirt, this defect may adversely affect the entire barcode decoding result for each scan, making the entire scan invalid. There were drawbacks such as a decrease in the reading rate of the information code when scanning the information code twice, leading to a decrease in reading accuracy.

The present invention was made in order to eliminate the above-mentioned drawbacks, and its purpose is to be able to perform stable reading without being affected by the quality of barcode symbols, thereby improving the barcode reading rate. The object of the present invention is to provide a very innovative information code reading device for a label reader device.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a label 1 on which an example of a barcode applied in the present invention is printed. That is, the above barcode has, for example, two decimal digits of information, and each of the five black zones has one digit of information code A.
and B, and these information codes A and B.
A start code ST and a stop code SP are placed between them, and a top margin consisting of a white area is placed before and after each barcode.
TM and bottom margin BM are provided. In the above barcode, the width of each white zone between the black zones is kept constant to reduce code reading errors, and the information codes A and B are each made up of five black stripes. A 2out of 5 cord is used, with only two of the zones being thicker than the others. In this case, the width of the thin black zone and the width of the white zone are set equal, the width of the thick black zone is set to three times the width of the thin black zone, and the widths of the top margin TM and bottom margin BM are set equal. Each width is set to be larger than four times the width of the thick black zone.

FIG. 2 shows a schematic configuration of an optical head section 2 for scanning a bar code on a label 1. As shown in FIG.
That is, the laser beam output from the laser beam generator 3 is reflected by the mirror 4 and has its beam diameter adjusted by the condenser lens 5, and then passes through the hall mirror 6.
The light passes through the hole 6a and is reflected by the vibrating mirror 7, which vibrates back and forth as indicated by the arrow in the figure. The reflected beam is reflected by the label 1 due to the reciprocating vibration of the vibrating mirror 7.
The barcode on the label 1 is scanned by such scanning light. The light reflected by the label surface 1 by this scanning is further reflected by the vibrating mirror 7 and the hall mirror 6, and then is received by the photomultiplier tube 11 via the filter 8, the condenser lens 9, and the pinhole 10. Therefore,
By scanning the barcode on the label 1 with laser scanning light, a photoelectric conversion signal P ₀ in the form of a pulse train corresponding to the black and white pattern of the scanned barcode is outputted from the photomultiplier tube 11 as a time-series signal. In this embodiment, the scanning speed of the bar code by the optical head section 2 is set to 200 times/second.

By the way, the photoelectric conversion signal P ₀ obtained by the above-described scanning has a property that its signal level fluctuates due to unstable factors described in (i) to (v) below.

(i) Shading due to distortion of the optical system.

(ii) Changes in the surface condition of the barcode.

(iii) Distance change between the optical head section 2 and the scanned barcode.

(iv) Effect of reflected light on the background of label 1.

(v) Fluctuations and modulations in the received light level due to disturbance light.

Photoelectric conversion signal due to unstable factors as mentioned above
An amplification conversion circuit 12 shown in FIG. 3 is provided to cope with level fluctuations of P ₀ . That is, the third
In the figure, numeral 13 denotes an AGC circuit which receives the photoelectric conversion signal P ₀ via a preamplifier 14, which optimizes the alternating current component of the signal P ₀ . like this
The photoelectric conversion signal P ₀ that has passed through the AGC circuit 13 is amplified to a required level by an AC amplifier 15, then sliced by a peak detector 16, and then processed by a flip-flop 17 to produce a low level signal corresponding to a black zone and a low level signal corresponding to a white zone. It is converted into a slice signal _P1 which is binarized into a high level signal and a high level signal.
The slice signal _P1 is inputted via the interface section 18 to a decoder/controller 19, which will be described later, and which is a control circuit device. The optical head section 2, amplification/conversion circuit 12, and interface section 18 described above are integrated into a unit to constitute a barcode reader head section.

The decoder/controller 19 whose block diagram is shown in FIG.
We aim to speed up and parallelize signal processing as a dual MPU system using That is, the master MPU 2 which is the decoding means in FIG.
0 is a slave that performs task management and is a means of decoding.
The MPU 2 executes signal processing under the control of the master MPU 20, and an outline of the arithmetic processing assignment of each MPU 20 and 21 is as follows. That is,
The slave MPU 21 processes all the signals from the barcode reader head section, and also transfers the intermediate code of the barcode in response to a request from the master MPU 20. In addition, the master MPU 20 controls the operation panel CP, manages external synchronization signals, executes output programs of various specifications, etc.
The slave MPU 21 is managed by decoding the intermediate code of the bar code from the slave MPU 21 . In addition, each MPU 20, 21 is equipped with a so-called operation self-test system that mutually monitors each other's operations to check whether the operations are normal or not.
We also check for disconnections in the transmission line between the controller 19 and the barcode reader head, and check the operating status of the head.If there is a problem, check the display panel.
Display error on DP.

Furthermore, in FIG. 4, the slice signal _P1 output from the barcode reader head section is sent to the own width data counter 2 via the interface section 22.
3 and a scanning synchronization signal inputted to the black background width data counter 24 and outputted from the barcode reader head section in synchronization with the scanning by the optical head section 2.
P ₂ is input to the control signal generation circuit 25 via the interface section 22 . Each data counter 23, 24 is controlled by a counter control signal _P3 outputted by the control signal generation circuit 25 in response to the scanning synchronization signal _P2 , and receives slice signals corresponding to the white zone and black zone of the barcode. _P1 is counted and a digital data signal _D0 corresponding to the white background width and black background width is sequentially output. The data signal D ₀ thus output is sent to the first data buffer 28 or the second data buffer 2 via either the pass switch 26 or 27 which is turned on alternately.
9 is stored. In this case, slave MPU2
1, while the bus switch 27 is turned on and the data signal _D0 is stored in the second data buffer 29, the bus switch 30 is turned on to read the stored contents of the first data buffer 28, and the bus switch 26 is turned on. The operation of turning on the bus switch 31 while storing the data signal D ₀ in the first data buffer 28 and reading out the stored contents of the second data buffer 29 is repeated. Therefore, the processing of the data signal D ₀ by the slave MPU 21 is performed one after another without waiting until the data signal D 0 is stored, and the processing speed is increased. Further, _T1 is a decoding result output terminal, which outputs a decoding signal _P4 corresponding to the content of the scanned barcode decoded by the decoder/controller 19 via the input/output interface section 19a. _T2 is an external synchronization signal input terminal, and the decoder/controller 19 starts decoding the scanned barcode when receiving the external synchronization signal _P5 from this terminal _T2 via the interface section 19a. The operation panel CP is provided with a synchronous mode switching switch, and only when this switch is switched to the "external synchronous mode", the external synchronous signal input terminal _T2 is enabled.
Furthermore, when the synchronization mode changeover switch is switched to "internal synchronization mode (AUTO)", the decoder controller 19 starts decoding the barcode when the barcode enters the scanning field of view of the optical head section 2. automatically starts, and if the slice signal _P1 corresponding to the barcode is not input for a predetermined period of time, it is assumed that the barcode has passed through the scanning field and the decoding result is displayed on the panel.
DP and outputs a predetermined mode decoding signal _P4 from the output terminal _T1 . Such "internal synchronization mode (AUTO)" is effective when it is difficult to input the external synchronization signal _P5 .

Therefore, in the following, each data buffer 2
Slave MPU21 that processes the data signal _D0 stored in
FIG. 5, which shows in block form the operating functions of the master MPU 20 that manages the MPU 21, will be described. That is, 32 is a white background margin (corresponding to the top margin TM and bottom margin BM) input section, which corresponds to the white area among the data signals D ₀ from the data buffers 28 and 29 (hereinafter referred to as white background width data Wd). ) are input in scanning order. 33 is a white background margin comparison unit, which compares the white background width data Wd from the white background margin input unit 32 and the white background width reference value Ws from the reference value setting unit 34;
When Ws>Wd, a re-input command signal _S1 is output and fed back to the white background margin input section 32 by the OR circuit 35, thereby inputting the white background margin input section 32 to the new white background width data Wd. Make it ready for input. In addition, the white background margin comparison section 33
outputs an input command signal S ₂ and supplies it to the start-or-stop code input section 36 when the relationship Ws≦Wd holds. In addition, the above white background width reference value
Ws is determined according to the width of the top margin TM and bottom margin BM of label 1,
It can be changed by the user. On the other hand, the start or stop code input section 36
When receiving the input command signal S ₂ , the data signal
The white background width data Wd and the black background width data Bm (data signals corresponding to the black area of the barcode) in D ₀ are input in scanning order, specifically, the start code ST or bottom margin following the top margin TM. Enter stop code SP following BM. Reference numerals 37 and 38 are a start code checking section and a stop code checking section, respectively, which convert the input of the start or stop code input section 36 into the widths of the black zone and white zone of the start code ST or the black zone and white zone of the stop code SP. When the input matches the start code ST or stop code SP, a proper signal _S3 is output, and when they do not match, an improper signal S4 is output, and the _improper signal _S4 is output. is applied to the blank margin input section 32 as a re-input command signal via an AND circuit 39 and an OR circuit 35. Each of the functional parts described so far corresponds to the start code/stop code detection part.

On the other hand, 40 is a first digit size prediction unit which is a first digit width prediction means, and this unit calculates the digit width of the start code ST or stop code SP, for example, as in the well-known pulse width measurement method. It is calculated by counting clock pulses of a constant period from a pulse generation source (not shown) during each input period of the stop code SP, and the digit width of the start code ST or stop code SP calculated in this way is multiplied by a predetermined coefficient K. By doing so, the digit width of the first digit of the barcode, that is, the first scanned information code, is predicted, and the prediction result is output as the first digit size signal _S5 .
The above coefficient K is calculated based on the digit width of the information code A (or B) printed on the label 1 and the start code ST.
(or stop code SP). Therefore, the predicted digit width based on the first digit size signal _S5 is the digit width of the first digit information code. It will be shown accurately. Reference numeral 41 denotes a digit counter which receives the appropriate signal _S3 from the start code inspection section 37 and stop code inspection section 38 as a counting clear signal from the OR circuit 42. 1 manages 2 digits). That is, this digit counter 41 is initialized when receiving the proper signal _S3 , in other words, when the start code ST or stop code SP is detected.
The number of digits of the barcode corresponding to one scan can be counted, and as will be understood later, the count is increased every time one digit of the information code of the barcode is scanned. In addition, the digit counter 41 sequentially outputs a numerical signal _S6 corresponding to the counted content from the output terminal _N0 , and when the counted content reaches "1", it outputs a first digit switching signal from the other output terminal _N1 . Output S ₇ . Reference numeral 43 denotes a changeover switch, which turns on the contacts (J-K) when it receives the appropriate signal _S3 , in other words, when the digit counter 41 is initialized, and switches on the first digit changeover signal _S7 . In other words, when the count of the digit counter 41 reaches "1" or more, the contacts (J-L) are turned on. 44
is the nth digit data input section (n represents a natural number)
Although this is not shown, when receiving the proper signal _S3 from the start code inspection section 37 or the stop code inspection section 38 as an input command signal, the black background width data Bd and the white background width data Wd of the data signal _D0 are determined.
Enter. Therefore, this n-digit data input section 44
Inputs the information code of the barcode following the start code ST or stop code SP. 45 is the nth digit dimension calculation section, which is 1
The digit width data of the information code actually obtained when the information code for digits is scanned based on the first digit size signal S ₅ is converted into black background width data Bd inputted to the n-th digit data input section 44. and white background width data Wd
The calculation result is output as the n-th digit size signal _S8 . in this case,
The calculation of the digit width data of the information code for one digit by the n-th digit size calculation section 45 is performed, for example, as follows. That is, the n-th digit dimension calculation unit 45
In this case, the n-digit data input section 44 is the black background width data Bd.
When you start inputting (in other words, the start code
Counting of clock pulses of a fixed period is started from the point in time when the information code starts scanning after ST or stop code SP is scanned, and this counting operation is controlled by an input command signal _S11 from the digit size comparison section 48, which will be described later. It stops when the input operation of the nth digit data input section 44 is completed as the output is stopped, and the nth digit dimension signal _S8 is obtained based on the final counting result. It's summery. At this time, as will be understood from the explanation that follows, the output of the input command signal _S11 is stopped when the information code currently being scanned has been scanned for the predicted digit width. The eye size signal _S8 corresponds to the size data when the information code is actually scanned by the optical head section 2. and,
The n-th digit size signal _S8 is obtained from between the contacts (J-L) of the changeover switch 43 as a second digit width prediction means (n+
1) The first digit dimension signal S ₅ input to the digit dimension prediction section 46 and output from the first digit dimension prediction section 40 is the (n+1) digits from between the contacts (J-K) of the changeover switch 43. This is input to the eye size prediction section 46. still,
The reason why such a changeover switch 43 is provided is that the calculation algorithms for obtaining the first digit size signal _S5 and the nth digit size signal _S8 are different.
On the other hand, the (n+1)th digit size prediction unit 46 calculates the predicted digit width of the first digit information code and the predicted digit width of the second and subsequent information codes indicated by the first digit size signal _S5 . This is to add correction based on the digit width data obtained when the information code is actually scanned by the optical head 2.
Specifically, the (n+1)th digit size prediction unit 46
The first digit size signal S ₅ indicates the predicted digit width of the second digit information code and the predicted digit width of the first digit information code.
and the n-th digit size signal _S8 indicating the digit width data obtained when the first digit information code is actually scanned, and the predicted digit width obtained in this way is calculated as the second digit width. Output as the dimension standard value signal _S9 for the digit. Further, the (n+1)th digit size prediction unit 46
Dimension standard value signal S ₉ indicating the predicted digit width of the information code from the third digit onward and the predicted digit width of the nth digit information code.
It is obtained by averaging the nth digit size signal _S8 indicating the digit width data obtained when the nth digit information code is actually scanned, and the predicted digit width obtained in this way is ) is output as the dimension standard value signal _S9 for the digit. 47 is black background width data Bd and white background width data sent sequentially from the n-th digit data input section 44.
The adder calculates the sum of Wd (corresponding to the sum of the black area and white area of the scanned information code), and sequentially outputs the addition result as a data sum signal _S10 . 4
8 is the dimension reference value signal _S9 and data sum signal
This is a digit size comparison unit that compares S ₁₀ , which outputs an input command signal S ₁₁ for a period in which S ₉ >S ₁₀ and continues the input operation of the n-th digit data input unit 44 so that S ₉ ≦
When the relationship S ₁₀ is reached, the output of the input command signal S ₁₁ is stopped and the digit division end signal S ₁₂ is output, and this signal S ₁₂ clears the adder 47 to the initial state and also resets the digit counter 41. Make the count up. Reference numeral 49 denotes a divided data buffer as a storage means, which divides and stores the black background width data Bd and white background width data Wd from the n-digit data input section 44 for each digit of the barcode (in other words, each information code). The storage area is specified by the numerical signal _S6 from the digit counter 41. 50
is the numerical signal _S6 from the digit counter 41 and the digit setting section 5
This is a digit number comparison unit that compares the digit setting signal S ₁₃ from 1 to 1, and outputs a digit division processing stop signal S ₁₄ when the numerical signal S ₆ becomes equal to the digit setting signal S ₁₃ . Note that the digit setting signal _S13 by the digit setting section 51 is set according to the number of information codes that the barcode to be scanned has. 2), set the digit setting signal _S13 to "2". 52 is a final code input section, which receives the data signal when receiving the digit division processing stop signal _S14 .
Input the black background width data Bd and white background width data Wd of D ₀ . Therefore, the stop code SP or start code SP following the last information code of the scanned barcode is input to the final code input section 52. When the stop code SP or start code ST is input in this way, it is checked by the stop code checking section 53 or the start code checking section 54 to see if it is appropriate. A signal S ₁₅ is output. Reference numeral 55 denotes an AND circuit into which the proper signals _S3 and _S15 from the start code tester 37 and the stop code tester 53 are respectively input; Each appropriate signal S ₃
and S ₁₅ , and therefore each
The AND circuits 55 and 56 output a digit division success signal _S16 only when both the start code ST and stop code SP are detected from the data signal _D0 , and this output is sent to the OR circuit 57 for subsequent statistics. This is used as a start signal for determination, and such statistical determination is performed using data stored in the divided data buffer 49.

Next, regarding the data decoding operation according to the configuration shown in FIG. 2 is the first
An example of scanning in the direction of arrow Y in the figure will be described.

The data signal _D0 stored in, for example, the first data buffer 28 by the first scanning of the bar code of label 1 is first searched for a start code ST and a stop code SP. That is, at the start of the data decoding operation, the blank margin input section 3
2 is in an input enabled state, and the other start-or-stop code input section 36, n-digit data input section 44, and final code input section 52 are in an input stopped state. Therefore, the white background width data W ₄ in the data signal D ₀
is applied to the white background margin comparison unit 33 in scanning order via the white background margin input unit 32. If this white background width data Wd corresponds to the top margin TM of label 1, in other words, the white background width data Wd and the white background width reference value Ws from the reference value setting section 34
When the relationship between Ws and Wd becomes Ws≦Wd, the white background margin comparison unit 33 outputs the input command signal S ₂ . In response to the output of the input command signal _S2 , that is, the detection of the top margin TM, the start-or-stop code input section 36 is switched to an input enabled state, and the black background width data Bd and the white background width data Wd in the data signal _D0 are input. are input to the start code checking section 37 and stop code checking section 39 in scanning order. Such input data Bd, Wd is the start code
If it matches ST, the start code checking section 37 outputs a proper signal _S3 . This proper signal
_S3 is given as an input command signal to the n-th digit data input section 44 to switch it to an input enabled state, and is also given to the digit counter 41 as a count clear signal to clear the count contents to the initial state "0". do. If the input data Bd, Wd do not match the start code ST and, of course, also do not match the stop code SP, both the inspection sections 37 and 38 output a rejection signal _S4 , which is sent to the white background margin input section 32. is given as a re-input command signal to
The above-described top margin TM detection operation is then performed again. Now, as mentioned above, the start code
When ST is detected, the first digit size prediction unit 40
By counting the width of the start code ST and multiplying the calculation result by a predetermined coefficient K,
Predict the digit width of the information code A following the start code ST, and use the prediction result as the first digit size signal S ₅
Output as . At this time, the changeover switch 43 is
Contacts (J-K) according to the initialization of the digit counter 41
Therefore, the above first digit dimension signal
S ₅ is input from the changeover switch 43 to the (n+1)th digit dimension prediction unit 46 as a dimension reference value signal S ₉ to the digit dimension comparison unit 48 . On the other hand, the adder 47 outputs a data sum signal S10 that increases sequentially in accordance with the sum of the black background width data Bd and the white background width data Wd that are input in scanning order to the n-th digit data input unit ₄₄ ,
This signal S ₁₀ is also input to the digit size comparison section 48 .
Then, in the digit size comparison section 48, the dimensional reference value signal _S9 and the data sum signal _S10 are compared, and when the relationship _S9 ≦ _S10 is satisfied, a digit division end signal is sent.
Output S ₁₂ . When the digit division end signal _S12 is output in this way, in other words, when the scanning of the first digit information code A is completed, the count content of the digit counter 41 counts up to "1" and the corresponding digit is counted up. counter 41
A numerical signal S ₆ corresponding to "1" and a first digit switching signal S ₇ are output from the numeral 1. Then, the first digit switching signal S ₇
At the same time, the changeover switch 43 is switched to the ON state between the contacts (J-L), and the first digit storage area Q1 of the divided data buffer 49 is specified by the numerical signal _S6 , and the nth digit data is input to this area Q1. Part 4
Black background width data corresponding to information code A from 4
Bd and white background width data Wd are stored. Following the scanning process of the first digit information code A, the second digit information code B is scanned.
First, the (n+1)th digit size prediction unit 46, in response to the switching operation of the changeover switch 43, selects the first
Digit size signal S ₅ (corresponding to the predicted digit width of the first digit information code A) and n from the nth digit size calculation unit 45
The digit size signal _S8 (corresponding to the digit width data when information code A is actually scanned) is averaged and the average value is output as the dimension reference value signal _S9 for the second digit information code B. do. Here, the digital data signal _D0 obtained by scanning the information code is based on the binary slice signal _P1 obtained by slicing the photoelectric conversion signal P0 from the optical head section ₂ . The steepness of the rising and falling waveforms of the signal P ₀ allows the predicted digit width of the information code based on the first digit size signal S ₅ to accurately match the actual digit width obtained when scanning the information code. The above is desirable. however,
It is inevitable that the rising and falling waveforms of the photoelectric conversion signal P ₀ are dulled to some extent, and for this reason, when scanning the information code, the digital data signal D ₀ (particularly the black background width data
Bd) input start time is delayed, the digit width when the information code is actually scanned is reduced by the above delay time, that is, there is an error in the predicted digit width based on the first digit size signal _S5 . A condition may be induced. In order to cope with such a situation, in this embodiment, as described above, the (n+1)th digit size prediction unit 46 generates a first digit size signal indicating the predicted digit width by the first digit size prediction unit 40. By taking the average of S ₅ and the n-th digit size signal S ₈ indicating the digit width data obtained when information code A is actually scanned, the above error is compressed, and the information code to be scanned next. The predicted digit width of B is corrected. Therefore, the dimension reference value signal S ₉ newly outputted as described above and the data sum signal S ₁₀ outputted from the adder 47 corresponding to the second digit information code B are transferred to the digit dimension comparison section 48. When the digit size comparison section 48 outputs the digit division end signal _S12 , the count content of the digit counter 41 counts up to "2" and corresponds to "2". A numerical signal _S6 is output. Then, the second digit storage area _Q2 of the divided data buffer 49 is specified by this numerical signal _S6 , and this area _Q2
Black background width data Bd and white background width data Wd corresponding to the information code B from the n-th digit data input section 44 are stored. At the same time, the digit number comparison unit 50
, the numerical signal S ₆ corresponding to the above "2" is compared with the digit setting signal S ₁₃ which has been set to "2" in advance from the digit setting section 51, and at this time, each of the signals S ₆ and S ₁₃
Since they are equal, the digit number comparison section 50 outputs a digit division processing stop signal _S14 . Then, the final code input section 52 is switched to an input enabled state, and each data Bd, Wd in the data signal _D0 is input to the stop code inspection section 53 and the start code inspection section 54 in scanning order. When such input data Bd and Wd match the stop code Sd, a proper signal is sent from the stop code inspection section 53.
_S15 is output, and as a result, the OR circuit 57 outputs a digit division success signal _S16 .

When the first scanning of the barcode on label 1 is completed in this way, the second and subsequent operations are repeated in the same way, and the information codes A and B on label 1 are stored in a predetermined storage area of the divided data buffer 49. are stored sequentially. Furthermore, during the above-described scanning, if the white background width data counter 23 and the black background width data counter 24 shown in FIG. 4 overflow, that is, if there is an excessive defect in the width of the white zone or black zone of the barcode. (For example, when there is a defect of 30 mm or more), the master MPU 20 interrupts the barcode decoding process and converts the data signal D stored in the first data buffer 28 or the second data buffer 29 by this scanning. Exclude ₀ from processing. If label 1 is attached to the product in the upside down direction as shown in Figure 2, the stop code SP will be detected first by the above scanning, and subsequent barcodes will be detected. Decoding is performed backwards. Therefore, two types of table values are prepared for the program for executing the barcode decoding process: forward and reverse.

However, mast MPU20, slave MPU2
1 determines whether or not a predetermined standard amount DS of data for each digit (information code A, B) of the bar code of label 1 has been stored in the divided data buffer 49 based on the digit division success signal _S16 , and
The stored data is deciphered by statistical judgment. In this embodiment, so-called "majority match determination" and "N consecutive match determination" can be arbitrarily selected by an internal switch.

In other words, if "majority match determination" is adopted,
The read data of each digit of the barcode (data corresponding to information codes A and B) stored in the divided data buffer 49 after each scan has reached the standard amount DS. Each item is statistically judged independently. At this time, the read data may include defective data that cannot be deciphered as information code A or B, but this defective data is not treated as valid data for majority match determination. The data that occupies the largest number of valid data is determined to be appropriate data and is output. Note that the minimum value of the reference quantity for majority judgment can be set using an internal switch, and digits whose valid data count is less than this minimum value will not be decoded, and only that digit will be displayed as an error. Do the following. Furthermore, since the configuration of this embodiment has the feature that each digit (information code A, B) of the scanned barcode is processed independently, even if only one information code has a defect, the other normal information code will be used as valid data for majority match determination. Therefore, the number of valid data required for majority match determination is increased compared to the conventional configuration in which the read data obtained for each scan is treated as valid data only when all information (all digits) is normal. This improves the throughput (data processing efficiency) of the entire device.

On the other hand, when "N consecutive match determination" is selected, when the read data of each digit of the stored barcode matches N times in a row in the scanning order, the read data is determined to be proper data and output. do. In this case, if the read data includes defective data, it is determined that the defective data does not exist. That is, even if the same read code continues N times with defective data in between, this is treated as proper data. Note that the number of matches N can be arbitrarily set (for example, 1 to 7 times) by an internal switch.

By the way, the following is described on the scanned barcode side.
If a failure such as (vi) to (x) occurs, the slice signal _P1 obtained by the scanning may not be correctly binarized.

(vi) Decreased contrast ratio values of black and white areas of the barcode.

(vii) Label 1 soiled.

(viii) White areas in black areas when printing barcodes.

(ix) Light reflected by the resin coating on the surface of label 1.

(x) If the product to which Label 1 is attached is wrapped in a transparent resin sheet, the light reflected from that sheet.

Therefore, the device according to the present invention can improve the problem that the barcode reading rate decreases due to the above-mentioned obstacles. That is, 2
When the decoder/controller 19 having MPUs 20 and 21 reads the start code ST or stop code SP of the scanned barcode, the decoder/controller 19 reads the first digit of the scanned barcode based on the dimensions of the read code ST and SP. In addition to predicting the size of the information code, the size of the information code after the second digit is corrected based on the digit width data of the information code obtained by actually scanning the information code in the previous step. The bar code to be scanned is divided into each digit (each information code), and the subsequent decoding process is performed independently for each digit divided as described above. Therefore, as in the case of scanning a barcode with uniformly scattered defects as described in (vi) to (x) above multiple times, the information code of all digits of the barcode cannot be obtained each time it is scanned. Even in such a case, the information code can be processed independently for each readable digit, and as a result, the barcode reading rate can be improved. An example is shown in FIG. 6 to supplement the above explanation. Label 1 in Fig. 6 shows an example in which dirt OB is scattered on its surface, and the scanning of its barcode is indicated by the arrows SC 1 to SC ₁ in the figure.
Assume that the process is performed n times as indicated by SCn. In this case, in the first to third scans SC ₁ to SC, the start code ST, information code B, and stop code SP
is readable, but information code A becomes unreadable. At this stage, information code B is determined as proper data by "majority match determination" or "N consecutive match determination", and the decoding result is displayed on the display panel DP and output from the output terminal _T1 . . After that, the 4th to 6th scans
When SC to SC are performed, information code A also becomes readable and is determined to be proper data. Therefore, even barcodes that are normally difficult to read can be read.

Incidentally, it goes without saying that the present invention is not limited to the above embodiments.

According to the information code reading device of the label reader device according to the present invention, as is clear from the above description, even when the quality of the barcode symbol is low due to obstacles such as dirt, it is possible to stably read the barcode symbol. This has an extremely excellent effect of improving the barcode reading rate.

[Brief explanation of the drawing]

The drawings relate to one embodiment of the present invention.
The figure shows an example of a label, Figure 2 shows an outline of the optical head section, Figure 3 is an electrical configuration diagram of the amplification conversion circuit of the barcode reader head, and Figure 4 shows the decoder controller (control circuit). 5 is a block diagram showing the main functional parts of the decoder/controller, and FIG. 6 is a diagram corresponding to FIG. 1 for explaining the operation. In the figure, 1 is a label, 2 is an optical head section, 19 is a decoder controller (control circuit device), and 20 is a label.
is the master MPU (decoding means), 21 is the slave MPU
(Decoding means), 40 is a first digit size prediction unit (first digit width prediction unit), 46 is an (n+1)th digit size prediction unit (second digit width prediction unit), 49 is a divided data buffer (storage means).

Claims (1)

[Claims] 1 Scan the bar code multiple times from a label displaying a series of bar codes in which an information code of a predetermined number of digits is placed between the start code and stop code, read the information code in the bar code, and read the information code in the bar code. In a label reader device that decodes the contents of an information code by statistical judgment based on the reading results of each scan, the start code or stop code that is scanned first in the scanned barcode is scanned after that based on the digit width of the start code or stop code. A first digit width prediction means predicts the digit width of the first digit information code, and the predicted digit width by this first digit width prediction means and the information code of the nth digit (n is a natural number) are actually scanned. a second digit width prediction means for predicting the digit width of the (n+1)th digit information code based on the digit width obtained by the digit width prediction means; a storage means for storing data divided into digits based on the width;
An information code reading device for a label reader device, characterized in that a control circuit device is provided with a decoding means for independently decoding the information code stored in the storage means for each digit.