JP2677805B2 - Code reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]   The present invention uses a code (for example, bar code) displayed on the medium.
Scanning) with a photoelectric conversion unit, etc.
Decode the information shown into a signal that can be processed by a calculator
The present invention relates to a code reading device for outputting, in particular, a code reading and
The present invention relates to a code reading device that improves the accuracy of decoding.
You. [Conventional technology]   Generally, this type of code reading device is used for documents, surface of articles, etc.
Displayed on various media according to various code systems
The code is photoelectrically converted by a scanner such as an optical reader,
The obtained electrical signal is calculated by a computing device such as a microprocessor.
It is decoded and output so that it can be processed. This
In the case of, the displayed codes are bar code and carla.
There are special display codes such as codes and general characters.
In order to code, the display method has a certain standard.
ing. This standard is a rule regarding display interval and display range.
For example, for barcodes,
Standard [JIS X 0502] (Issued the first printing on April 30, 1987) No.
Items from pages 3 to 9 and American National St.
andard [ANSI: MH10.8M-1983] page 8 etc.
There are things that are. When reading these displays
Is a typical optical reader used as a scanner,
Among them, not only pen type but also self scan
Training hand wand model or stationary model
It may be a different one.   FIG. 10 shows an optical system that is a typical example of a known code reading device.
Circuit of code reading device (hereinafter referred to as bar code reader)
It is a block diagram which shows an example of a structure.   Further, FIGS. 11 to 14 show the known bars shown in FIG.
FIG. 4 is an explanatory diagram illustrating an operating state of the code reader.   In FIG. 10, 101 is a photoelectric conversion unit and 102 is a fast
Space detector, 103 is the first edge detector, 104 is a counter
Part 105, a start margin determination part (start determination
Section), 107 is a decoder section, and 110 is a stop margin determination section.
(Stop determination unit).   In FIG. 10, the photoelectric conversion unit 101 includes photoelectric converters 1 and 2
The photoelectric conversion device 1 is composed of a binarization circuit 2 and an optical converter on the medium.
Two, a space with high emission efficiency and a bar with high light absorption rate
In this state, the signs displayed alternately are detected and the specified voltage level is detected.
The binarization circuit 2 converts the bell electric signal a and outputs it.
Upon receiving the electrical signal a, for example, a white space with high light reflectance
As a low level (hereinafter referred to as "L"),
For example, the black bar with high light absorption is at a high level (hereinafter referred to as “H”
It is converted into the binarized signal b.   The fast space detector 102 includes a switch 3 and a space.
And a binary detector from the photoelectric conversion unit 101.
No. b through the switch 3 and space detector 4 or switch
5 The switch 3 initially applies the reset signal.
Is switched to the space detector 4 side. Photoelectric
The conversion unit 101, as shown in FIG.
Display position when scanning starts from the front of the display position
"L" in the space in front of (first space)
The signal is supplied to the space detector 4. Space detector 4
Is connected to the first counter circuit 8 of the counter unit 104.
The signal c generated by the space detector 4 is changed to the above-mentioned display position.
Is the "L" signal obtained by the space in front of the table
Then, the detection signal e is supplied to the first counter circuit 8. First
The counter circuit 8 is cleared by the supply of the detection signal e.
Start counting the clock signal input after that.
I do.   At this time, the switch 3 is switched to the first position by applying the detection signal e.
Switch to the 1-edge detection unit 103 side to detect the 1st edge
Wait for The first counter circuit 8 detects the detection signal e
Count the number of clock signals during the duration of
The count value of the counter circuit 8 is set in the first constant register 9.
Overflow value (for example, the photoelectric conversion unit 101
When you reach a state where you are stopped on the space)
The overflow comparator 10 outputs a reset signal, and the first counter
The entire circuit including the input circuit 8 is reset.   On the other hand, the count value j of the first counter circuit 8 is
Through 11 the first counter of the start margin determination unit 105
The first margin comparator 14 is supplied to the memory 12, and the first margin comparator 14 will be described later.
The count of the first counter memory 12 when the signal h
The value is compared with the set value of the second constant register 13.   As shown in FIG. 11 a, the first counter circuit 8
Count value j, that is, supplied to the first counter memory 12
Count value of signal line 1_M(The space immediately before the barcode
Count time) and set in the second constant register 13.
Start margin time is t_SAnd then t_M> T_S
Then, as shown in Fig. 12 (a), the scanning
It is determined that the card position is far enough from the barcode.
It is.   Also, as shown in Fig. 11b, the start of scanning
Even if the position is far from the barcode, dirt P
If there is such a problem, the dirt P
Count time at t_M1, Dirt P to bar code position
Count time at t_M2Respectively t_SSmaller,
(T_M1<T_S, T_M2<T_S), After all it is not possible to judge the start
Judge.   On the other hand, as shown in FIG. 11c, the start of scanning
When the position is close to the barcode, it is shown in Fig. 12 (c).
Scan from the scanning start position to the barcode.
Und time t_MIs t_M<T_SAnd this is also the start format
Judge that it is not possible to determine.   In the case shown in Fig. 11 b and c above, starter
A reset signal is output from the gin determination unit 105 and the bar code
No reading is done.   Here, as shown in FIG. 11a, t_M> T_SIs
And the detection output e of the space detector 4 is supplied to the switch 3.
Then, the switching device 3 is switched to the switching device 5 side. First edge inspection
The first edge detector 6 of the output unit 103 is arranged in front of the display position.
Photoelectric conversion when reaching the first barcode from pace
Change from "L" to "H" output from section 101 (see FIG. 11)
The change signal f associated with (a point) is detected, and the first change detection signal h
Is output. The change detection signal h indicates that the switch 5 has the second edge.
While switching to the detection unit 7 side, the first of the counter unit 104
Is supplied to the counter circuit 8, and the first counter circuit 8 is
The count of the clock signal is started. In addition, the switch 11
The stop margin is determined by the detection output e of the pace detector 4.
It is switched to the determination unit 110 side. The second edge detector 7
The edge at the end of the first bar code, i.e.
The change from “H” to “L” at the point is detected, and the second change detection
The intelligent signal i is output.   On the other hand, in the first counter circuit 8, the first edge detector 6
Counting starts when the first edge is detected, and
As for the count value, the second edge detector 7 detects the second edge.
At the time (when the signal is output from the signal line i)
Stored in the second counter memory 15 of the margin determination unit 110.
It is. The second counter memory 15 outputs the count value to the signal line o.
To the second change detection signal signal i
From the signal line t through the switch 16 switched by
It is supplied to the coder unit 107. That is, at this point, the 11th
The width of the bar code (bar B1) from point a to point b in the figure
The corresponding count value is supplied to the decoder unit 107.
Become.   Next, the second edge detector 7 operates as shown in FIG.
Change from “H” to “L” at the point and from “L” at the point C in the figure
A change from "H" to "H" is detected sequentially,
The input value is supplied to the decoder unit 107.   Follow the same procedure for each barcode space.
The count value corresponding to the width and the width of the bar is sequentially decoded.
Supplied to 107.   As described above, the start margin determination unit 105 displays
The space in front of the position satisfies the start margin
If you are not satisfied, check the
Output a set signal to start barcode reading.
Absent.   The switching unit 22 detects the first change from the first edge detection unit 103.
When the signal h is supplied, the stop margin determination unit 110
The signal u output from the above is supplied to the decoder unit 107.   In this case, the second constant value of the start margin determination unit 105
The register 13 has a preset constant corresponding to the start margin.
Is set, and the set value n is stored in the first margin comparator 14.
Supplied. The first margin comparator 14 receives the first change detection signal.
When the signal h is input, the operation starts and the first counter
The count value m from the memory 12 and the setting of the second constant register 13 are set.
Outputs a reset signal when comparing m with a fixed value n
The bar code reading operation.
You.   After scanning some barcodes, scan again.
When entering the space, that is, the "H" at the two points in FIG.
At the time of the change from "L" to "L", the first counter circuit 8
Start counting the check signal, and the count value
Stored in the second counter memory 15 of the margin determination unit 110.
It is. The second margin comparator 15 includes a second counter memory 15
Count value t_NAnd the 7th constant register 42 is set
The value t corresponding to the stop margin_CCompare with   Note that this set value t_CIs the bar code reader operator.
Or, set it after considering the fluctuation of the scan speed during operation.
Is a constant that is determined and is shown in a or b of FIG.
When the scan speed is slow or fast
As shown in the waveforms of Figures 14 (a) and (b), t_N> T_CThat
For example, it is determined that the barcode reading is completed and the
The switching device 22 is switched, and the first comparison from the second margin comparator 15 is performed.
The signal v is supplied to the decoder unit 107, and the decoder unit 107
Command command.   On the other hand, as shown in Figure 13c, stop merge
There is dirt P'on the space reserved as
, T_N<T_CWhen it becomes, as shown in Fig. 14 (c).
In addition, the dirt P'is mistakenly read as a bar code,
It may cause malfunction. On the other hand, the seventh constant
In the register 42, the constant s corresponding to the stop margin is preset.
Is set, and the set value s is set to the second margin comparator 20.
Supply to a bar or space count value set above
When the value exceeds s, the second margin comparator 15
2 The comparison signal v is supplied to the decoder unit 107 via the switch 22.
Then, a decoding stop instruction is given to the decoder unit 107.   In the above description, the space is white and the bar is black.
The signal levels are set to "L" and "H" respectively.
It is not limited to.   As for the related art of this type,
There is one described in JP-A-60-35707. [Problems to be solved by the invention]   In the above-mentioned conventional technique, the display position of the barcode is
A certain distance with the space in front (from the wide space width
Over a large distance) or over a certain time (wide space)
(The time is greater than the count time of the scan width)
When it is detected, the barcode reading starts and the
The space in front of the bar code display position is
As a service, a certain distance or more or a certain time or more
As a result, when displaying the barcode,
It is difficult to increase the density of bar code display.
However, there is a high possibility that the space will become dirty and
There is a problem that the operation is likely to occur.   Further, in the above-mentioned conventional technique, a bar or a space is used.
If the count value for the
-Decode operation is considered to be the end of code reading.
Since it is controlled to start, the barcode reader
Depending on the scan speed, the space required for the stop margin
As the pace / bar width changes, a faster scan
Wide stop margin width to accommodate high speed
The barcode must be displayed as a result.
When displaying, it is difficult to make the bar code display high density
And, moreover, there is a possibility that the margin will get dirty.
However, there is a problem in that the malfunction is likely to occur due to the increase in the value.   The present invention solves the above-mentioned problems of the prior art,
Its purpose is to enable high density bar code display and
Code reading that reduces the occurrence of malfunctions during signal reading
It is to provide a device. [Means for solving the problem]   In order to achieve the above object, the present invention provides a display on a medium.
Photoelectric conversion unit that reads the generated code and outputs a binary signal
And a change detection signal and a change detection indicating the change of the binary signal
Count that counts the time interval of the signal with the clock signal
The timing part that outputs the signal and the number of times the change detection signal is supplied
Judged as reading the first code when the constant number is reached
And a start determination section that outputs a start determination signal.
Decode count signal by supplying code start signal
The decoder unit to be processed and the start judgment signal are not yet supplied.
Not using the count signal, the second and subsequent marks
Of the sign to the count value of the code and the count value of the code immediately before it.
Compare the size with the value multiplied by the constant that represents the allowable range,
If the count value of the second and subsequent codes is larger, read
It is determined that the detected code is non-code, and
Output a reset signal to return to the state before scanning
The unsigned judgment unit and the start judgment signal have not been supplied yet.
In addition, using the count signal, the second and subsequent codes
Of the sign to the count value of
Compare the size with the value obtained by multiplying the constant that represents the volume range, and
Normal if the count value of the sign after the th is larger
It is judged that the reading of the code of
And a code reading end determination unit that outputs a decoding start signal to
The first means comprises.   Further, in order to achieve the above object, the present invention
Photoelectric that reads the code displayed on the screen and outputs a binary signal
A conversion unit, a change detection signal indicating when the binary signal changes, and a change detection signal.
The time interval of the aging detection signal is counted by the clock signal.
Timing signal output unit and the change detection signal
The first code was read when the number of salaries reached a predetermined number
Start judgment that outputs a start judgment signal
The count signal is supplied by the constant section and the decode start signal.
And the start decision signal
Not supplied yet, and using the count signal, the second
The count value of the code after the eye and the count of the code immediately before it
The ratio with the value is larger than the constant that represents the allowable range of the sign.
If the ratio is larger, the code read
Is determined to be unsigned, and each part in the device is read before reading.
Non-code determination unit that outputs a reset signal to restore the state
And the start judgment signal has already been supplied, and
Count value of the second and subsequent codes using the count signal
And the ratio of the count value of the code immediately before it to the code allowance
Compare whether it is larger than the constant that represents the range, and then use that ratio
If the normal code is read when is large,
To output a decoding start signal to the decoder section.
The second means is provided with a signal reading end determination unit.   Further, in order to achieve the above object, the present invention provides a medium
Light that reads the code displayed above and outputs a binary signal
An electric conversion unit, a change detection signal indicating a change in binary signal, and
The time interval of the change detection signal is counted by the clock signal
Timing unit that outputs a count signal and change detection signal supply
I read the first code when the number of times reached a predetermined number
Start judgment that outputs start judgment signal
Section and the decoding start signal
If the start decision signal is
Not supplied, and using the count signal, the second
Subsequent code count values are constants that represent the allowable range of codes.
The divided value is larger than the count value of the code immediately before it.
If the squid is compared and the divided value is larger, read
It is determined that the code that has been
An unsigned symbol that outputs a reset signal to restore the state before taking
No. judgment unit and start judgment signal have already been supplied,
Moreover, using the count signal, the code of the second and subsequent codes is
The value obtained by dividing the und value by a constant indicating the allowable range of the sign is
Compare if it is greater than the count value of the code immediately before it,
Reads the normal code when the divided value is larger
Is judged to have ended, and the decoding start signal is sent to the decoder section.
Means for outputting a code reading end determination unit
Is provided. [Action]   According to the first means, the start determination unit is
When the number of times the intelligent signal is supplied reaches a predetermined number, the first code is
A start mark indicating that it is possible to start by judging that it has been read
A constant signal is output, and the start judgment signal is
If not supplied yet, use count signal
For the count value of the descending sign and the count value of the preceding sign
The size is compared with the value multiplied by a constant that represents the allowable range of the code.
If the count value of the second and subsequent codes is greater than
Then, it is judged that the read code is non-code and
After resetting, the code reading end determination unit displays the start determination signal.
If the count signal is already supplied, the second signal is used.
Subsequent code count values are constants that represent the allowable range of codes.
The divided value is larger than the count value of the code immediately before it.
Compare the squid, and if the divided value is larger, the regular mark
No. of the count signal
Start decoding.   Further, according to the second means, the start determination unit is
When the number of times the change detection signal is supplied reaches a predetermined number, the first
A star indicating that the code can be read and the start is possible.
Output the start judgment signal and the non-code judgment unit
If the signal is not supplied yet, the count signal is used and 2
Count value of the code after the th and count of the code immediately before it
Value is larger than the constant that represents the allowable range of the code.
Compare the squid and read if the ratio is larger
Reset the inside of the device by determining that the sign is a non-sign,
The code reading end determination unit has already supplied the start determination signal.
If the count signal is detected, the count signal is used
The ratio between the count value and the count value of the code immediately before it is
It is compared whether it is larger than the constant representing the allowable range of the code, and the
If the ratio of is larger, the normal code reading is terminated.
It is judged that the count signal has been completed and the decoding of the count signal is started.
Let   Further, according to the third means, the start determination unit
Is the maximum when the number of times the change detection signal is supplied reaches the specified number.
Judge that the first code has been read and indicate that the start is possible
Outputs the start judgment signal, and the non-code judgment unit starts
If the judgment signal is not yet supplied, use the count signal
The count value of the second and subsequent codes to the allowable range of codes
The value divided by the constant is the count value of the code immediately before it.
If the divided value is greater than
Then, it is judged that the read code is non-code and
After resetting, the code reading end determination unit displays the start determination signal.
If the count signal is already supplied, the second signal is used.
Subsequent code count values are constants that represent the allowable range of codes.
The divided value is larger than the count value of the code immediately before it.
When the squid is compared and the divided value is larger, the normal
It is judged that the reading of the code is completed, and the count signal
Start decoding.   The first to third means are all coded
Readability is judged using the ratio of count values.
Therefore, the specifications of the readable code, that is,
Create specifications for code width (length) and scanning speed (residence time)
The start margin and stop margin
There is no need to set a sufficiently large margin,
With specifications that have a start margin and a stop margin
can do. 〔Example〕   Hereinafter, embodiments of the present invention will be described with reference to the drawings.   FIG. 1 shows an embodiment of a code reading device according to the present invention.
FIG. 3 is a block configuration diagram in which the code reading device is a bar code.
1 illustrates an example of a reading device.   In FIG. 1, 101 is a photoelectric conversion unit, and 106 is a code reading end.
End determination unit, 107 a decoder unit, 108 a start determination unit, 10
Reference numeral 9 is a non-code determination unit, and 111 is a clock unit.   As shown in FIG. 1, the photoelectric conversion unit 101 is a bar code.
Scan and read the high level "H" and low level
It is converted into a binary signal consisting of "L". The timekeeping unit 111 uses the light
Detects the change state of the binary signal supplied from the electrical conversion unit 101
Generate a tabulated detection signal when a change is detected, and
The time interval of the detection signal is counted by the clock signal,
A count signal indicating the count value is generated. Start format
The setting unit 108 supplies the change detection signal supplied from the clock unit 111.
Detects the presence or absence of the first code based on the number of pays and detects it
Occasionally a start judgment signal is generated. The decoder unit 107 is
Decodes the count signal supplied from the clock unit 111
Then, the processing result is output as read data. Unsigned
The determination unit 109 receives the start determination signal from the start determination unit 108.
Is supplied from the timekeeping unit 111 only when there is no supply of
Counting the second and subsequent codes based on the count signal
A constant that represents the allowable code in the count value of the value and the code immediately before it
Compared with the multiplication count value multiplied by, the former count
Reset if value is greater than the latter multiply count value
Generate a signal. The code reading end determination unit 106 starts
Only when the start judgment signal is supplied from the judgment unit 108
Based on the count signal supplied from the timer unit 111
The count value of the current code and the count of the code immediately before it.
Value multiplied by a constant that represents the allowable code
And the count value of the former is the multiplication count value of the latter.
Decode start signal is generated when the
It is supplied to the unit 107 to start decoding.   Next, FIG. 2 shows the detailed structure of this embodiment shown in FIG.
It is a block diagram showing a configuration.   In FIG. 2, 101 is a photoelectric conversion unit, and 102 is fast.
Space detector, 103 is the first edge detector, 104 is a counter
Data, 106 is a code reading end determination unit, 107 is a decoder unit, 10
8 is a start determination unit, 109 is an unsigned determination unit, 111 is a time counting unit
And each of the components 101 and 106 shown in FIG.
Through 109 and 111.   Further, 7 is a second edge detection unit, which is a first space detector.
Source detection unit 102, first edge detection unit 103, counter unit 10
4, the second edge detection unit 7 constitutes the clock unit 111 as a whole.
I have.   Then, the photoelectric conversion unit 101 outputs a code such as a bar code as an optical signal.
The signal is read by the electric converter 1 and the read signal is sent through the signal line a.
Is supplied to the binarization circuit 2 for low level "L" and high level.
Convert to a binary signal consisting of "H" and send the converted binary signal.
First space detection section 1 of clock section 111 via line b
Supply to 02.   In the timekeeping unit 111, the first space detection unit 102
The switch 3 is switched to the 3r side shown by the input of the reset signal.
It has been switched, and it is shown in Fig. 3s by the signal input of signal line e.
Switched to the side. Therefore, the switch 3 is configured so that the signal line b
Is connected to the space detector 4 and the binary signal on the signal line c is scanned.
When indicating a pace (eg "L"), signal
A detection signal is generated on the line e, and the switch 3 is switched to the 3s side.
As a result, the binary value obtained on the signal line b of the photoelectric conversion unit 101
The signal passes through the switch 3 to detect the first edge from the signal line d.
It is supplied to the switch 5 of the unit 103. Switch 5 is reset
Since it is switched to the 5r side by the input of the signal,
The line d is connected to the first edge detector 6 via the signal line f.
You.   The first edge detector 6 outputs the binary signal of the signal line f with a space.
Change from a bar to a bar (eg "L" to "H")
When it does, and generates the first change detection signal on the signal line h
I do. The first change detection signal of the signal line h is supplied to the switcher 5.
Then, the switch 5 is switched to the 5s side, and at the same time, the counter
It is supplied to the first counter circuit 8 of the unit 104. First count
Circuit 8 counts by supplying the first change detection signal.
The value becomes 0, and after that, the clock signal CL
Und operation starts. In this case, the first counter circuit 8
Is not only for inputting the reset signal, but also for the second
Second change detection supplied from the detector 7 via the output line i.
Similarly, the count value becomes 0 by the supply of the intelligence signal,
After that, start counting the clock signal CL, and
Also in this case, the count value is output to the signal line i. First count
The count value output from the output circuit 8 is the overflow ratio.
In the comparator 10, the value set in the first constant register 9 is exceeded.
Count value of the first counter circuit 8 compared with the flow value
Overflows (for example, the scanner is stopped midway)
In case of), overflow comparator 10 is reset
Output a signal.   The second edge detector 7 switches the switch 3 to the 3s side and
Corresponding to the switching of the switch 5 to the 5s side, the photoelectric conversion unit 101
A binary signal is supplied, and the first change detection signal of the signal line h
Change from bar to space (“H” to “L”)
And change from space to bar (from "L"
"H") is detected respectively, and the second change detection signal is detected at the time of detection.
It occurs on the signal line i. The second change detection signal is the first count
Of the start determination unit 108
It is supplied to the second counter circuit 28.   The start determination unit 108 is based on the second change detection signal.
The rising edge of the first element (first code)
First element that is continuously supplied after detection
(First code) Falling element and subsequent elements (code
No.) change and the count value is the fourth constant.
When the number preset in the number register 29 is reached,
Generate a start judgment signal on Line C
Counting the number of spaces and bars to do
).   The second counter circuit 28 uses the second change detection signal of the signal line i.
The counter is sequentially incremented by the application of
Send the count value to line a. The second counter
The circuit 28 has a counter value of 0 when the reset signal is input.
Will be cleared. The fourth constant register 29
Indicates the number of elements (2 or more) used for start judgment
Is set in advance, and the set value
It is supplied to the first margin comparator 30 via. First merge
The comparator 30 sets the count value of signal line A and the setting of signal line A.
Compared with the value, the count value is set in the fourth constant register 29
If it exceeds the value, the start judgment signal is output to the signal line c.
I do.   The switch 31 is a second change detection signal of the second edge detector 7.
To the switch 39 and the switch 32 of the non-code determination unit 109,
Is one of the switching unit 21 and the switching unit 16 of the code reading determination unit 106.
Supply to somebody. Switching of the switching device 31 is performed with a reset signal.
Performed by the start determination signal of the start determination unit 108
It is. The switch 31 is on the 31r side when a reset signal is applied.
And the second change detection signal is applied from the signal line i.
Then it is switched to the 31s side.   The switching unit 11 applies the reset signal and the first edge detector.
It is switched by the application of the first change detection signal from 6,
When the first change detection signal is applied, the counter of the first counter circuit 8 is
The count value is stored in the first counter memory 12 and the second counter memo.
Supply to Ri 15.   The non-code determination unit 109 determines at least the first bar and the space.
Compare the count values of the cells and their elements (sign)
The counter value of (the count value of the first counter memory 12) is
Counter value of the immediately preceding element (code) (second previous count)
Constant value (count value stored in input memory 35)
6 Contents of the constant register 36) Reset when it exceeds
The signal is sent to the signal line service. That is, when determining the start
At least first without looking at the start margin
I made a comparison of the count values of the bar and space of
As you can see, it is not a legitimate element (code) reading
When it is determined that the reset signal is output.   In this case, the first counter memory 12 is
Stores the count value and sends this count value to the signal line m
I do. Then, it is stored by applying the reset signal.
The count value is reset.   The fifth constant register 33 is (wide element / slow).
(Scan speed) A preset count value greater than
The set value is output to the signal line output. Switch 34
When the reset signal is input,
Is connected to and the count value of the fifth constant register 33 is set to the second value.
It is supplied to the counter memory 35 last time and stored there. No.
2 The previous counter memory 35 signals the stored count value.
The second multiplier 37 is supplied to the second multiplier 37 via the line
The count value of the first previous counter memory 35 and the sixth constant number
Wide element / narrowe set in Dista 35
Multiply with a value larger than the element. The product output is
It is supplied to the third margin comparator 38 via the signal line U.   The third margin comparator 38 uses the first count from the signal line m.
The count value of the memory 12 and the multiplication output of the second multiplier 37
In comparison, if the former exceeds the latter 3, the signal line
Output a signal.   The switching device 40 receives a signal (i) when a reset signal is input.
Connect the signal line service and the reset output line to obtain the signal line service.
The signal is output as a reset signal. Also, (ii) signal
When the start judgment signal is input from the line
Separate from the reset output line and reset to the reset output line
No signal is output.   The switching unit 32 of the non-code determination unit 109 changes from the signal line D to the second change.
Signal line m and signal line key only when the signal
And the counter stored in the first counter memory 12
Value is supplied to the second previous count memory 35 to detect the second change.
When no intelligent signal is input, disconnect the signal line m from the signal line key
You.   The switch 39 receives the second change detection signal from the signal line D.
Signal line m and signal line t only when
The count value of the unter memory 12 is supplied to the decoder unit 107.
You.   The switch 21 and the switch 39 are disconnected from the second edge detector 7.
It is turned off by the second change detection signal supplied via the relay 31.
The switching device 39 can be replaced by the
1 Element stored in counter memory 12
No.) count value, and the switch 21
Therefore, as described later, it is stored in the second counter memory 15.
The count value of each element (sign)
And sends it to the decoder unit 107.   The switch 27 receives the start judgment signal from the signal line c.
Only when it is hit, that is, the star from the start determination unit 108
It is switched according to the power judgment signal.
The first value of the code reading determination unit 109
Supplied to the counter memory 17 last time. In this case, the signal line m
The count value of
It is the counter value used for the determination of the element.   In addition, the code reading end determination unit 106 determines that the currently read code is
Element count value, that is, in the second counter memory 15
The stored count value is the count of the previous element.
Value, that is, the value stored in the first previous counter memory 17
A constant with a count value (setting of the third constant register 18
Value) times the output signal is sent to the signal line u
You. The second counter memory 15 is supplied from the signal line 1.
The count value of the first counter circuit 8 of the counter unit 104 is recorded.
The stored count value is sent to the signal line o. switching
The device 16 detects the second edge via the switch 31 and the signal line E.
Only when the second change detection signal from the instrument 7 is input
The signal line o and the signal line p are connected, and the second counter memory 15
The count value is supplied to the first previous counter memory 17. No.
1 The previous counter memory 17 has the counter voltage applied from the signal line p.
Memorize the count value and store the stored count value via the signal line q.
And supplies it to the first multiplier 19. The third constant register 18 is
From wide / narrow element of barcode
A large constant is set in advance, and this set value is the signal line.
It is supplied to the first multiplier 19 via r. First multiplier 19
Is the count value stored in the first previous counter memory 17
And the setting value of the third constant register 18 are multiplied, and the multiplication output is
The signal is supplied to the second margin comparator 20 via the signal line s.   The second margin comparator 20 is input via the signal line o.
The second counter memory 15 count value and the first multiplier 19
Compare with the multiplication output, and if the former value exceeds the latter value
Then, the output signal is sent to the signal line u.   When the reset signal is input, the switch 22 receives the signal line u.
And signal line v are separated, and start determination is made via signal line c.
When the start determination signal is applied from the unit 108, the signal line u
And the signal line v are connected. Therefore, the start determination unit 10
Read the code from the time when the start judgment signal from 8 is input.
Start decoding the output signal of the determination unit 106 to the decoder unit 107
It is supplied as a signal and the decoder operation in the decoder unit 107 is performed.
Start the work.   The decoder unit 107 displays the element of the read barcode.
Based on the count value of the clock signal CL corresponding to the
To decode the meaning of the bar code.
Yes, for example, with the configuration shown in FIG.
I have.   Functions of each component block in the decoder unit 107
Is like this:   The bit image converter 23 uses the second edge from the signal line i.
It operates by supplying the second change detection signal of the detector 7;
Count value input from signal line t into bit image
It is converted and recorded in the bit image memory 24 via the signal line w.
Remember If an error occurs during this conversion, reset
Output signal.   The bit image memory 24 is applied from (i) the signal line w.
Stored bit image, (ii) from signal line v
Depending on the decoding start signal applied, the stored
Image to the character converter 25 via signal line x
Send, (iii) When reset signal is input, store
Such as clearing the existing bit image
Perform the operation.   The character converter 25 uses the bit image memory 24
Converts the applied bit image to a character, which
Is supplied to the output circuit 26 via the signal line Y. In addition,
Reset signal if an error occurs during lactate conversion
Is output.   Then, the output circuit 26 is a character applied from the signal line Y.
To a display means (not shown) by sending the output signal to the output line z.
Supply. When the transmission of this character signal is completed,
Output a set signal.   Next, FIG. 3 shows a non-code determination unit used in the present invention.
A first embodiment of the configurations of 109 and code reading end determination unit 106 is shown.
It is a block configuration diagram.   In FIG. 3, 120 is a counter memory (non-code judgment
First counter memory 12 of unit 109, code reading end determination unit 106
(Corresponding to the second counter memory 15) of the
Memory (second previous counter memo of unsigned determination unit 109)
35, first previous counter memo of code reading end determination unit 106
(Corresponding to 17), 140 is a constant register (non-sign determination unit 1
The sixth constant register 36 of 09, the code reading end determination unit 106
3 corresponds to register 18), 150 is a multiplier (unsigned)
The second multiplier 37 of the judging unit 109 and the second multiplier 37 of the code reading end judging unit 106
1 corresponds to the multiplier 19), 160 is a comparator (non-code determination unit 1
09 third margin comparator 38, code reading end determination unit 106
This corresponds to the second margin comparator 20).   The non-code determination unit 109 and the code read end determination with the above configuration
According to the configuration of the constant unit 106, the start margin and the stop
To read the barcode to judge the margin
The current element (code) coun
Value and the count value of the previous element (sign)
It is compared with the value multiplied by a constant. And unsigned decision
When the start judgment signal is not yet supplied, the unit 109
, The second and subsequent codes stored in the counter memory 120
The count value of the
Set to the constant register 140 to the count value of the code immediately before
Is multiplied by a constant that represents the allowable range of the sign
Compare, if the former is greater than the latter, the code read
Is determined to be non-coded, and the code read end
The setting unit 106 has already supplied the start determination signal,
The code of the second and subsequent codes stored in the counter memory 120.
Unt value and the value previously stored in the counter memory 130
The count value of the immediately preceding sign is set in the constant register 140.
Compare with the value multiplied by a constant that represents the allowable range of the sign
However, if the former is larger than the latter, the legitimate code is read.
It is determined that the
The start space is determined by the unit 109 and the code reading end determination unit 106.
The status of the start or stop space.
Things.   Further, FIG. 4 shows the non-code determination unit 10 used in the present invention.
9 shows a second embodiment of the configuration of 9 and code reading end determination unit 106
It is a block block diagram.   In FIG. 4, 170 is a divider,
Same as components shown in Fig. 3 Same as components
It is marked.   In the example shown in FIG. 4, the counter memory 120
The count value of is a constant set in the constant register 140.
The divided value and the previous count value of the counter memory 130
Are comparing. Then, the non-code determination unit 109
Counter memory when the judgment signal is not supplied yet.
The count value of the second and subsequent codes stored in 120 and the previous time
The counter of the previous code stored in the counter memory 130
The ratio with the input value is set in the constant register 140.
Compared with the constant that represents the allowable range of the sign, the former is more than the latter
If it is large, it is judged that the read code is non-code.
In addition, the code reading end determination unit 106
When the constant signal is already supplied, the counter memory 120
The count value of the second and subsequent codes stored in
Counter of the previous code stored in the input memory 130
Sign of the ratio with the value set in the constant register 140
The former is greater than the latter than the constant that represents the allowable range of
If it is not, it is judged that the reading of the legitimate code is completed.
The non-code determination unit 109 and the code read end determination
Depending on the fixed part 106, the start space or stop space
The state of the source is determined. In this configuration
Therefore, the non-code determination unit 109 and the code shown in FIG.
A function similar to that of the read end determination unit 106 can be achieved.   Further, FIG. 5 shows a non-code determination unit used in the present invention.
A third embodiment of the configurations of 109 and the code reading end determination unit 106 is shown.
It is a block configuration diagram.   In FIG. 5, the same structure as the components shown in FIG. 4 is used.
The same symbols are attached to the components.   In the example shown in FIG. 5, the counter memory 120
Of the count value of the previous counter memory 130
The value divided by the divider 170 and set in the constant register 140
The comparator 160 compares it with a constant. And unsigned
The start determination signal is not yet supplied to the signal determination unit 109.
Sometimes, the second and subsequent ones stored in the counter memory 120
The sign count value is set in the constant register 140
The value obtained by dividing by the constant indicating the allowable range of the sign and the previous count
Count value of the immediately preceding code stored in the data memory 130
And compare if the former is larger than the latter, read
Code is judged to be non-code, and the code is read.
The end determination unit 106 has already supplied the start determination signal.
2nd and later stored in the counter memory 120 when
The count value of the sign of is set in the constant register 140
Value divided by a constant that represents the allowable range of the sign
Counter of the previous code stored in the input memory 130
Value, and if the former is greater than the latter, the
It is judged that the reading of the code is completed.
From the non-code determination unit 109 and the code reading end determination unit 106,
Determining start space or stop space status
Is what you are doing. Even with this configuration, FIG.
And the non-code determination unit 109 and the code reading end shown in FIG.
A function similar to that of the end determination unit 106 can be achieved.   Here, the operation of the code reading device in the present invention will be described in the sixth
This will be described with reference to FIGS.   FIG. 6 shows the start code in the code reading device of the present invention.
FIG. 7 is an explanatory view of the constant operation, and FIG. 7 is a start judgment of FIG.
It is a related waveform diagram of constant operation.   In FIG. 6, line a is the scan start position.
Scan line when is far enough from the barcode
Then, FIG. 7 (a) is a read waveform at the time of the scan.
You. In this case, the first bar (first bar code) B1
The counter value corresponding to the reading time is t_A,first
At the time of reading space (first space code) S1
The corresponding count value is t_B, Where A is a constant, t_B<
A × t_AAnd the barcode can be read.
Is determined.   Also, as shown in line b in FIG. 6, the scan
Even if the start position of the
If dirt P exists in the middle of the process, it is shown in Fig. 7 (b).
As shown, the read waveform is a false read due to the dirt P.
Taken signal is obtained and counted against the read signal
Value t_A1Is obtained. In this case, the space following the dirt P
Count value t_B1Is t_B1＞ A × t_ASo the dirt P is a bar
Not considered a code. And the original barcode
Count value of first bar (first bar code) B1
t_AFollowed by the first space (the first space
Code) t of the count value of S1_BBetween and t_B<A × t_Abecome
Therefore, at this point, the bar code reading
It is judged to be acceptable.   Furthermore, as shown in line c in FIG.
Even if the start position of the
Stbar (first bar code) B1 count value t_AAnd fur
Of space count (first space code) S1
t_BBetween and t_B<A × t_ARead the barcode.
It is determined that the tori can be started.   In this way, in this embodiment, the barcode
The count value t of the first bar code (first bar code) B1_AWith
Value of A times A × t_AThan the barcode fasts
Count value of pace (first space code) S1_BIs small
When it is determined that the barcode reading has started
Therefore, the space just before the barcode can be short.
And Therefore, the barcode is displayed in a high-density state.
Of the first bar code
The probability that dirt P will adhere to the space located in front is low.
It becomes difficult to cause malfunctions when reading due to dirt P
It gets harder. In this case, some constant A is as described above.
And larger than wide element / narrow element
Any value will do.   Next, FIG. 8 shows a code in the code reading device of the present invention.
FIG. 9 is an explanatory diagram of a read determination operation, and FIG. 9 is a symbol of FIG.
It is a related waveform diagram of a read determination operation.   In FIG. 8, line a has a slow scan speed.
The scan line at that time is shown in FIG. 9 (a).
Waveform read at time, line b is scan speed
Figure 9 (b) shows the scan line when scanning is fast.
This is the read waveform during scanning, and line c is the scan scan
The speed is fast and there is dirt P at the position after the last barcode.
Figure 9 (c) shows a scan line at the time of the scan
Is a read waveform of.   In FIGS. 8 and 9 (a) to (c), the scan
Count value of the element (code) read by the
Is the count value (t_AAlso
Is t_B) Is larger than a certain constant A times,
It is determined that the reading is completed, and the decoding operation is executed.   Thus, according to this embodiment, the barcode is scanned.
Regardless of the scan speed when scanning
The space required for the gin and the width of the bar are determined, and the stop
It is now possible to use barcodes with a small width
Enabled to display barcodes in high density
And the dirt P adheres to the position after the last barcode.
Readability based on dirt P that can reduce the possibility
Malfunctions at times are reduced.   Even in this case, a constant A is as described above.
And larger than wide element / narrow element
Any value can be used, for example, A = 8 can be selected and implemented.
it can. 〔The invention's effect〕   As described above, the respective inventions according to claim 1 to claim 3
According to the above, whether or not the code can be read is checked by the change detection signal.
Since the judgment is made using the
Possible code specifications, ie code width (length) and scan
When determining the specifications of speed (residence time),
Margin (scan start position and first sign
Interval) and stop margin (of the last code and scan)
It becomes possible to select the minimum distance between the end position)
Therefore, the width of the displayed code is narrowed by that amount and the code is displayed.
Codes can be densified and read
There is an effect that it is possible to reduce mistakes at the time of
On top of that, there is no
The next code is read because the code is not decoded.
There is also an effect that the time required for preparation is unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block configuration diagram showing an embodiment of a code reading device according to the present invention, and FIG. 2 is a block configuration diagram showing a detailed configuration of the embodiment shown in FIG. FIG. 3 is a first diagram of the configurations of the non-code determination unit and the code reading end determination unit used in the present invention.
FIG. 4 is a block configuration diagram showing an embodiment, and FIG. 4 is a second configuration of a non-code determination unit and a code reading end determination unit used in the present invention.
FIG. 5 is a block configuration diagram showing an embodiment, and FIG. 5 is a third configuration of a non-code determination unit and a code reading end determination unit used in the present invention.
FIG. 6 is a block diagram showing an embodiment, FIG. 6 is an explanatory diagram of a start judgment operation in the code reading apparatus of the present invention, FIG. 7 is a waveform diagram related to the start judgment operation of FIG. 6, and FIG. FIG. 9 is an explanatory diagram of the code reading determination operation in the reading device, FIG. 9 is a waveform diagram relating to the code reading determination operation of FIG. 8, and FIG. 10 is a block configuration diagram of a bar code reader which is a known code reading device. 12 and FIG. 12 are explanatory diagrams of the start determination operation of the bar code reader shown in FIG. 10, and FIGS. 13 and 14 are explanatory diagrams of the code reading determination operation of the bar code reader shown in FIG. 101 ... Photoelectric conversion section, 104 ... Counter section, 106 ... Code reading end determination section, 107 ... Decoder section, 108 ... Start determination section, 109 ... Non-code determination section.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-57-6977 (JP, A)                 JP 58-3073 (JP, A)                 JP-A-58-221467 (JP, A)

Claims (1)

(57) [Claims] A photoelectric conversion unit that reads the code displayed on the medium and outputs a binary signal, a change detection signal that represents the time when the binary signal changes, and a count signal that counts the time interval of the change detection signal with a clock signal. A time measuring unit for outputting, a start judging unit for judging that the first code is read when the number of times of supplying the change detection signal reaches a predetermined number and outputting a start judging signal, A decoder unit that decodes the count signal, and the start determination signal has not been supplied yet, and
Using the count signal, the magnitudes of the count value of the second and subsequent codes and the value obtained by multiplying the count value of the immediately preceding code by a constant indicating the allowable range of the code are compared, and the magnitudes of the second and subsequent codes are compared. When the count value is larger, the read code is determined to be non-code, and the non-code determination section that outputs a reset signal that returns each unit in the apparatus to the state before reading and the start determination signal have already been output. The count signal is supplied and the magnitudes of the count value of the second and subsequent codes and the count value of the code immediately before that are multiplied by a constant representing the allowable range of the code are compared. If the count value of the second and subsequent codes is larger, it is determined that the reading of the regular code is completed, and the code read end determination unit that outputs the decoding start signal to the decoder unit. Code reading device, characterized in that it comprises. 2. A photoelectric conversion unit that reads the code displayed on the medium and outputs a binary signal, a change detection signal that represents the time when the binary signal changes, and a count signal that counts the time interval of the change detection signal with a clock signal. A time measuring unit for outputting, a start judging unit for judging that the first code is read when the number of times of supplying the change detection signal reaches a predetermined number and outputting a start judging signal, A decoder unit that decodes the count signal, and the start determination signal has not been supplied yet, and
If the ratio between the count value of the second and subsequent codes and the count value of the immediately preceding code is greater than a constant representing the allowable range of the code using the count signal, and if the ratio is greater In, the read code is determined to be non-code, a non-code determination unit that outputs a reset signal for returning each unit in the apparatus to the state before reading, and the start determination signal has already been supplied, and, If the ratio between the count value of the second and subsequent codes and the count value of the immediately preceding code is greater than a constant representing the allowable range of the code using the count signal, and if the ratio is greater The code reading device further comprises: a code reading end determining unit that determines that the reading of the regular code is completed and outputs the decoding start signal to the decoder unit. 3. A photoelectric conversion unit that reads the code displayed on the medium and outputs a binary signal, a change detection signal that represents the time when the binary signal changes, and a count signal that counts the time interval of the change detection signal with a clock signal. A time measuring unit for outputting, a start judging unit for judging that the first code is read when the number of times of supplying the change detection signal reaches a predetermined number and outputting a start judging signal, A decoder unit that decodes the count signal, and the start determination signal has not been supplied yet, and
Using the count signal, it is compared whether the value obtained by dividing the count value of the second or subsequent code by a constant representing the allowable range of the code is greater than the count value of the code immediately before, and the value obtained by the division. Is large, the read code is determined to be non-code, and a non-code determination section that outputs a reset signal that restores each unit in the apparatus to the state before reading, and the start determination signal have already been supplied. Moreover, by using the count signal, it is compared whether the value obtained by dividing the count value of the second and subsequent codes by a constant representing the allowable range of the code is greater than the count value of the code immediately before that, and performing the division. When the value is larger, it is determined that the reading of the regular code is completed, and a code reading end determination unit that outputs the decoding start signal to the decoder unit is provided. Winding device.