JPH055143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a barcode detection device for detecting code information of a barcode of an object to be inspected.

[Technical background of the invention and its problems]

2. Description of the Related Art Conventionally, barcode detection devices have detected barcodes in which a code is formed using a prescribed number of bars in one column, for example as shown in FIG. Here, one column refers to an array of bars at six arbitrary positions in the example shown in FIG. 1, and FIG. 1 is an example of a 2-out-of-5 code format. This is an arrangement in which bars are arranged at any two of the five bar positions excluding the start bar S.

Next, a detection device for detecting the above barcode will be explained with reference to FIGS. 2 and 3 a to 3 d. FIG. 2 is a block diagram of the barcode detection device, and FIGS. 3a to 3d are timing charts for explaining the operation of the barcode detection device. It is assumed that a barcode signal (shown in FIG. 3b) corresponding to the barcode shown in FIG. 3a is input to the barcode detection device. When a clock is generated from the oscillator 3, the synchronization circuit 1 inputs the barcode signal and the clock, creates and outputs a signal (shown in FIG. 3c) synchronized with the rising edge of the barcode signal. The pitch clock generation circuit 2 is
The output of the synchronous circuit 1 and the clock from the oscillator 3 are input, and a bar code pitch signal (as shown in FIG. 3d, pitch=T ₁ ) is output. The output of the pitch clock generating circuit 2 is used as a clock signal, and the bar code signal is input as data to the register 4. In the register 4, the presence or absence of a bar is stored one bit at a time, and the contents are decoded by the decoder 5.

In this way, if the barcode to be detected is reliably printed on the object to be inspected, barcode detection can be performed accurately.

However, in recent years, inkjet printers and the like that can print on objects to be inspected in a non-contact manner have been adopted as devices for printing barcodes. This is a method of spraying ink in the form of dots, so if the air pressure of the inkjet printer is not properly adjusted, the ink may fly off, especially on the first bar, as shown in Figure 4. This occurs during printing, and is a cause of false detection in conventional circuits.

[Purpose of the invention]

This invention was made in view of the above circumstances, and although it has a relatively simple configuration, it is not affected by dirt caused by ink splatters etc. that occur when using an inkjet printer etc. It is an object of the present invention to provide a barcode detection device that can reliably detect barcodes.

[Summary of the invention]

The outline of this invention for achieving the above object is as follows:
In a barcode detection device that detects the code form of a specified number of barcodes in one column,
means for supplying a barcode signal corresponding to a barcode attached to an object to be inspected; and a means for supplying the barcode signal supplied by the means, having a period corresponding to the pitch of the barcode, and ,
bar pitch signal generating means for generating first and second bar pitch signals having different phases; and a bar pitch signal generating means for generating first and second bar pitch signals having different phases, and using the first and second bar pitch signals generated by the means as clocks to generate the bar code signal for at least one column. a delay means for holding;
a first counting means for counting the barcode signals using the first bar pitch signal; a first determining means for determining whether the number of barcode signals counted by the means corresponds to a specified number; a second counting means for counting the barcode signals using the second bar pitch signal; a second determining means for determining whether the number of barcode signals counted by the means corresponds to a prescribed number; means for selecting a first or second bar pitch signal determined to correspond to a specified number of bar pitches based on the determination results of the first and second determination means; and a first or second bar pitch signal selected by the means. This feature is characterized in that barcode detection is performed using the following methods.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram of a barcode detection device which is an embodiment of the present invention. In FIG. 5, the barcode detection device includes a bar pitch signal generating means 10, a barcode signal authenticity determining means 20, and a barcode information delaying means 30.
, a signal selection means 40 , a register 61 , and a decoder 62 .

The bar pitch signal generating means 10 generates two types (first and second) bar pitch signals having different phases in synchronization with the bar code signal.
The bar pitch signal generation means 10 includes a first AND circuit 11, a synchronization circuit 12, an oscillation circuit 13, a pitch pulse generation circuit 14, and a first flip-flop (referred to as first FF, hereinafter the same) 15. It consists of. The first AND circuit 11 is
A barcode signal and the output of the first F.F 15 are input, and the ANDed result is output. The transmitting circuit 13 generates a clock signal. The synchronization circuit 12 inputs the output of the first AND circuit 11 and the clock signal from the oscillation circuit 13, and creates a leading edge signal g having a predetermined pulse width from the first rise of the barcode signal. and output it. The pitch pulse generation circuit 14 inputs the tip signal g and the clock signal, and generates two pulses having different phases similar to the pitch of the barcode signal.
The seed bar pitch signals h and i are output. Further, the pitch pulse generating circuit 14 closes the gate of the first AND circuit 11 via the first F/F 15 in order to take in only the first data in one column.

The bar code signal authenticity determining means 20 counts the bar code signals using two types of bar pitch signals h and i having different phases, which are output from the bar pitch signal generating means 10, and determines whether this count value is normal in one column. It is determined whether the number is equal to or not. The barcode signal authenticity determination means 20 includes first and second counters (counting means) 21 and 22, and second and third counters (counting means) 21 and 22.
F.F23, 24 (first and second determination means). The first counter 21 counts barcode signals using a bar pitch signal h,
When the count value reaches "3", a high level (hereinafter referred to as "H" level) is output. Similarly,
The second counter 22 counts the barcode signal using the bar pitch signal i, and outputs an "H" level when the count value reaches "3".
This is 2 out of 5 including start bar S.
This is because the specified number of bars is three. The second and third F.Fs 23 and 24 input the outputs of the first and second counters 21 and 22 to their clock terminals, respectively, and input the output of one FF to the other FF.
They are mutually input to the D terminals of the two.

The barcode information delay means 30 uses two types of bar pitch signals h and i having different phases as clocks to create barcode information k and l from the barcode signal, delays this by one column data, and outputs it. . The barcode information delay means 30 includes a first register 31 which is a storage means that inputs the bar pitch signal h and the barcode signal and outputs the barcode information k, and a first register 31 that inputs the bar pitch signal i and the barcode signal and outputs the barcode information k. The second register 32 is a storage means for outputting code information l.

The signal selection means 40 selects the two types of bar pitch signals k, i and the two types of barcode information k,
l and the output of the barcode signal authenticity determination means 20, and the barcode signal authenticity determination means 20
Based on the output of , valid bar pitch signals and bar code information are selected and output. The signal selection means 40 includes second to seventh AND circuits 41, 42,
43, 44, 49, 50, first and second OR circuits 45, 46, and fourth flip-flop 47
and a hexadecimal counter 48. Said second
The AND circuit 41 inputs the output of the second F.F 23 and the output k of the first register 31, ANDs them and outputs the result. Said third AND circuit 42
inputs the second F.F 23 and the bar pitch signal k, ANDs them and outputs the result. The fourth AND circuit 43 inputs the output of the third F.F 24 and the output l of the second register 32, ANDs them and outputs the result. The fifth AND circuit 44 is
The output of the third F.F 24 and the bar pitch signal i are inputted, and the ANDed result is output. The first OR circuit 45 is connected to the second AND circuit 41 and the fourth OR circuit 45.
The output from the AND circuit 43 is inputted, and these are ORed and output. Said second OR circuit 46
are the third AND circuit 42 and the fifth AND circuit 4
The outputs of 4 and 4 are input, and these are logically summed and output. The fourth F.F 47 is for setting the start and end of writing to the register 61, and is set when the output of the first OR circuit 45 becomes "H" level. Advance counter 48
is reset based on the output of The sixth AND circuit 49 inputs the output of the first OR circuit 45 and the output of the fourth F.F. Output. Said seventh AND circuit 5
0 is the output of the second OR circuit 46 and the fourth FF
It inputs the output of 47, ANDs them, and outputs a clock signal to be taken into the register 61 at the subsequent stage. The hexadecimal counter 48 counts the clock signal from the seventh AND circuit 50,
When counting "6", the fourth F.F 47 is reset.

The register 61 writes bar code information from the sixth AND circuit 49 in the signal selection means 40 based on the clock signal from the seventh AND circuit 50. The data written in the register 61 is input to a decoder 62 based on the output of the hexadecimal counter 48, and is decoded by the decoder 62.

The operation of the barcode detection device configured as described above will be explained based on timing charts shown in FIGS. 6A to 6L. FIG. 6A shows a 2-out-of-5 barcode, and ink is splattered near the start bar S by an inkjet printer. A barcode signal based on the barcode shown in FIG. 6A is obtained as shown in FIG. 6B.
Here, _T1 in the figure indicates the pitch of the barcode signal.

This barcode signal is sent to the first AND circuit 11.
When the input is input to the first F.F.
The barcode signal is output as is as the output of the AND circuit 11. The synchronous circuit 12 inputs the output of the first AND circuit 11 and the clock signal from the oscillation circuit 13, creates and outputs the tip signal g of the barcode signal shown in FIG. 6C. _T3 shown in FIG. 6 indicates the pulse width of this tip signal g. The pitch pulse generation circuit 14 is
The tip signal g of the synchronous circuit 12 and the oscillation circuit 1
From the clock signal No. 3, two types of bar pitch signals h and i having different phases approximate to the pitch _T1 of the bar code signal are created and output (as shown in FIGS. 6D and 6E). In this embodiment, bar pitch signals are used whose phases differ by 180°. Furthermore, the bar pitch signal k,i
The pitch T ₂ is a pitch where T ₁ = T ₂ or T ₁ < T ₂ . Further, the pitch pulse generation circuit 14 is connected to the first F.
The gate of the first AND circuit 11 is closed via F15, and operates so that only the first data in one column is input.

Next, the operation of the barcode signal authenticity determining means 20 will be explained. first and second counters 21,
22 converts the barcode signal into two signals having different phases.
Count the seed bar pitch signals h and i, respectively. Since the first counter 21 counts at the rising edge of the bar pitch signal k, it counts only the signal due to the first jump, and its count value is "1". On the other hand, since the second counter 22 counts at the rising edge of the bar pitch signal i,
The signal caused by the first flying dust is not counted, but
The original number of bars "3" in one column can be counted. Therefore, the second counter 2
2, the three conditions defined in one column are satisfied, and this output provides the output j of the third F.F24 as shown in FIG. 6F. This third FF
Based on the output of 24, it is determined that the bar pitch signal i is the more accurate signal among the two types of bar pitch signals.
The second F.F23 can be set to low level (hereinafter referred to as "low level") by inputting the output of the third F.F24.
(also called "L" level).

Next, the operation of the barcode information delay means 30 will be explained. The first register 31 takes in the barcode signal as barcode information based on the bar pitch signal h (as shown in FIG. 6G). On the other hand, the second register 32 takes in the barcode signal as barcode information based on the bar pitch signal i (as shown in FIG. 6H). Then, the first and second registers 31 and 32 output this content after being delayed by at least one column data, that is, by "6" clocks in this embodiment. For example, the second register 3
2 outputs barcode information l at point S shown in FIG. 6 (see FIG. 6 I).

Next, the operation of the signal selection means 40 will be explained. Since the "L" level of the second F.F 23 is input to one input terminal of the second and third AND circuits 41 and 42, the output thereof is at the "L" level. The fourth AND circuit 43 is connected to the third F.F2.
The output j of 4 and the output l of the second register 32 are ANDed to output the signal l shown in FIG. 6I.
This signal l is obtained as is as the output of the first OR circuit 45.

On the other hand, the fifth AND circuit 44 is connected to the third F.
Input the output j of F24 and the bar pitch signal i,
These are ANDed and a signal n shown in FIG. 6J is output. This signal n is obtained as is as the output of the second OR circuit 46.

The signal l obtained as described above is taken into the register 61 as bar code information, and the signal n is taken in as a clock signal. Here, since the clock signal n is output before the barcode information l is generated, the sixth and seventh AND circuits 4
9, 50, the fourth F.F 47, and the counter 48, a clock signal P (shown in FIG. 6K) necessary for loading the barcode information l into the register 61 is taken out, The barcode information is taken into the register 61. Therefore,
The register 61 receives the signal q shown in FIG. 6L. By decoding the contents of the register, the decoder 62 can accurately detect the 2-out-of-5 code format despite the presence of scatter.

If there is no scattering, the barcode signal authenticity determination means 20 determines that the barcode information based on the bar pitch signal h is valid, and based on this result, the signal selection means 40 selects the bar pitch as a clock signal. The signal h is selected, and the output of the first register 31 is selected as the barcode information. Therefore, accurate barcode detection can be performed regardless of the presence or absence of scattered particles.

It goes without saying that the present invention is not limited to the embodiments described above, and includes various modifications within the scope of the gist of the invention. For example, the bar pitch signal generating means 10 generates a pulse width of the tip signal g.
An auxiliary circuit may be provided to make _T3 variable depending on the position of the flying dot. Furthermore, in this embodiment, the phase difference between the bar pitch signals h and i was set to 180°, but
Not limited to this, depending on the flying dot, 90°,
It is also possible to generate a plurality of bar pitch signals instead of just two types of bar pitch signals.

〔Effect of the invention〕

As explained above, although the present invention has a relatively simple configuration, it is possible to reliably detect barcodes without being affected by dirt caused by flying ink from an inkjet printer, etc. A barcode detection device can be provided. Therefore, highly reliable barcode detection with fewer false positives is possible.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a 2-out-of-5 barcode format, Fig. 2 is a block diagram showing an example of a conventional barcode detection device, and Figs. 3 a to d.
4 is a timing chart for explaining the operation of a conventional barcode detection device, FIG. 4 is a schematic explanatory diagram showing ink scattering by an inkjet printer, and FIG. 5 is a barcode detection according to an embodiment of the present invention. Block diagram of the device, Figure 6A~
L is a timing chart for explaining the operation of the barcode detection device. 10... Bar pitch signal generation means, 20... Bar code signal authenticity selection means, 30... Bar code information delay means, 40... Signal selection means.

Claims (1)

[Claims] 1. In a barcode detection device for detecting the code form of a prescribed number of barcodes provided in one column, means for supplying a barcode signal corresponding to a barcode attached to an object to be inspected, and a barcode signal supplied by this means. bar pitch signal generating means for generating first and second bar pitch signals having a period corresponding to the pitch of the bar code and having different phases, in response to the supply of the bar code signal; a delay means for holding the bar code signal for at least one column using the generated first and second bar pitch signals as clocks; and a first counting means for counting the bar code signal by the first bar pitch signal. , a first determining means for determining whether the number of barcode signals counted by this means corresponds to a prescribed number; and a second counting means for counting the barcode signals using the second bar pitch signal. a second determining means for determining whether the number of barcode signals counted by this means corresponds to a prescribed number; and a determination that the number of barcode signals corresponds to the prescribed number based on the determination results of the first and second determining means. 1. A barcode detection device comprising: means for selecting a first or second bar pitch signal, and detecting a barcode using the first or second bar pitch signal selected by the means.