JPH05334482A - Bar code symbol reader - Google Patents

Abstract

PURPOSE:To obtain a sure double reading preventing function by inhibiting the reading of a bar code symbol until the separation of the bar code symbol from a bar code symbol reader is detected. CONSTITUTION:An image of a sheet including a bar code symbol 1 stored in a frame memory 4 is scanned by a rapid arithmetic circuit 5 and the detection of the existence of the symbol 1 and decoding are executed. At the time of ending the decoding, the circuit 5 clears a decoding permission flag 7, i.e., inhibits decoding. At the time of receiving the detection, decoding and check end signal of the symbol 1 from the circuit 5, a CPU 8 controls the operation of respective parts, and when the symbol 1 is not included in an image inputted to the memory 4, the removal of the symbol 1 is judged and sets up the flag 7. Consequently the sure double reading preventing function can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code symbol reading device for reading a bar code symbol, and more particularly to a "double reading" in a bar code symbol reading device using a two-dimensional image pickup device such as a video camera. Prevention ”function.

[0002]

2. Description of the Related Art At present, bar code symbols are used in many countries, and the types thereof are very large. Typical bar code symbols are JAN / UPC / EAN code, ITF (Interleaved 2 of 5) code, CODE
39, NW-7 code, CODE128, etc. Also, recently, two-dimensional bar code symbols having a large amount of information and a high recording density have begun to be proposed due to demands for expressing more information, sticking in a narrower space, and the like. As such a two-dimensional barcode symbol, C
ODE16K, CODE49, PDF417, DATA
CODE, etc.

These JAN / UPC / EAN codes, I
TF (Interleaved 2 of 5) code, CODE39, N
There are many types of devices for reading one-dimensional bar codes such as W-7 code and CODE128, and typical types include a pen type, a touch type, and a laser type. On the other hand, there are few types of devices for reading a two-dimensional barcode symbol, and the reading technique has not been established yet.

However, the basic method of reading a barcode symbol is almost the same as in the case of a conventional one-dimensional barcode even in the case of a two-dimensional barcode symbol. That is, the barcode symbol is irradiated with light from the light source, and the light reflected by the barcode symbol is condensed on the light receiving element inside the reading device. A barcode symbol is read by decoding the collected signal with an electric circuit configured by a microcomputer or the like.

Here, there are important problems other than reading technology,
That is, one of the functions required as a barcode symbol reading device is a "double-reading prevention" function that a once read barcode symbol cannot be read again. Especially at cash registers such as supermarkets,
This function is of course necessary.

The conventional bar code is JAN / UPC /
EAN code, ITE (lnterleaved 2 of 5) code,
In a device for reading a one-dimensional bar code such as CODE39, NW-7 code, CODE128, etc., if the read data is the same as the last time, the data is not transferred to the host computer as a "double reading prevention" function. There are employed methods such as a method of not reading the next bar code for a certain period of time after the data is transferred to the host computer, and a method of providing a switch for starting the reading and operating the switch by an operator.

[0007]

However, if the read data is the same as the previous one, the method of not transferring the data to the host computer does not cause a problem with the conventional bar code having a very short reading time. However, it is not a good method for a two-dimensional barcode symbol having a long reading time.

In addition, it is very difficult to set the fixed time by the method that the next bar code is not read for a fixed time after the data is transferred to the host computer. If the set time is long, it is difficult to read the next bar code. Moreover, there is still a problem that the same bar code is read twice when the set time is short. Further, if the operator leaves the sheet on which the barcode symbol is recorded, the operator will "read twice".

Further, in the method in which a switch for starting reading is provided and the operator operates the switch, there is a problem in that the number of parts is increased and the labor for operating the switch is required because the switch is provided. The present invention has been made in view of the above points, and provides reliable "double reading prevention".
An object is to provide a barcode symbol reading device having a function.

[0010]

In order to achieve the above object, a bar code symbol reading apparatus according to the present invention comprises an image pickup means for picking up an image of a bar code composed of a bar and a space, and an output signal of the image pickup means. A bar code symbol detecting means for detecting the presence or absence of a bar code symbol from the bar code, a state holding means for holding state information indicating a bar code symbol decoding permission / non-permission state, and a state information held by the state holding means. A bar code symbol decoding means for interpreting the content of the bar code symbol from the image of the bar code symbol imaged by the imaging means when indicating that the code symbol is in a decoding enabled state; and the bar code symbol decoding means. After decoding the bar code symbol by, the contents of the state information in the state holding means are And code disallowed state, then, at least once by the bar code symbol detection unit,
And a control means for setting the content of the status information in the status holding means to the decoding enabled state when the barcode symbol cannot be detected.

[0011]

That is, in the bar code symbol reading apparatus of the present invention, the control means sets the content of the state information in the state holding means to the decoding disallowed state after the bar code symbol is decoded by the bar code symbol decoding means.
After that, when the barcode symbol cannot be detected at least once by the barcode symbol detecting means, the content of the state information in the state holding means is set to the decode enable state so that the barcode symbol is read. The bar code symbol is not read (decoded) until it is detected that the bar code symbol has been removed from the device, thus preventing "double reading".

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration thereof. A sheet or the like including the barcode symbol 1 is illuminated by an illumination device (not shown), and the reflected light is incident on the video camera 2. The video camera 2 converts the optical signal into an electric signal, further adds a synchronizing signal or the like to form a video signal, and sends the video signal to the video circuit 3. The video circuit 3 separates the sync signal from the input video signal, and further A / D converts it to digitize it. The digitized signal is stored in the frame memory 4.

The image of the sheet containing the barcode symbol 1 stored in the frame memory 4 is scanned by the high-speed arithmetic circuit 5 (image information is detected from the memory 4) to detect the presence or absence of the barcode symbol 1 and the barcode. Decoding of symbol 1 is performed. The decoded contents are temporarily stored in the decoding result storage memory 6. The high-speed arithmetic circuit 5 clears the decoding permission flag 7 (decoding is prohibited) upon completion of the decoding.

The CPU 8 controls each component, for example, outputs a capture start signal for instructing capture of an image to the frame memory 4 to the video circuit 3, and outputs the barcode symbol 1 to the high-speed arithmetic circuit 5. The detection start signal of and the decoding start signal of the barcode symbol 1 are output,
Further, it receives the detection state signal of the bar code symbol 1 and the decoding and check end signal of the bar code symbol 1 from the high speed operation circuit 5 and controls the operation of each part. Further, when the barcode symbol 1 can be detected, the decoding permission flag 7 indicating whether or not the barcode symbol 1 can be decoded is set (decoding permitted), and is recorded in the barcode symbol 1 from the decoding result storage memory 6. Extracted information and controls the host interface circuit 9,
The information is transferred to a host computer (not shown).

The operation of the "double-reading prevention" mechanism in the bar code symbol reading apparatus having such a structure will be described below with reference to the flow chart of FIG. First, the CPU
8 outputs a capture start signal to the video circuit 3 to capture an image in the frame memory 4 (step S
1). After the completion of capturing the image, the CPU 8 outputs a barcode symbol 1 detection start signal to the high-speed arithmetic circuit 5, and the high-speed arithmetic circuit 5 detects the presence or absence of the barcode symbol 1 (step S2). Various methods are known for detecting the barcode symbol, and as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-23483,
A method of determining that there is a bar code symbol when it is confirmed that there are a plurality of parallel bars is known. Also,
With a two-dimensional barcode symbol such as PDF417 or DATA CODE, it is possible to detect the presence of the barcode symbol by confirming the presence of a characteristic portion such as a start big bar or an L-shaped outer frame. .. Then, the high speed operation circuit 5 outputs the detection result of the barcode symbol 1 to the CPU 8 as a detection state signal.

The CPU 8 judges whether or not the bar code symbol 1 is present in the image taken into the frame memory 4 by judging the detection state signal from the high speed operation circuit 5 (step S3). Then, when the bar code symbol 1 does not exist, the process returns to step S1 to instruct the image capture again. When the bar code symbol 1 is present, a decode start signal for the bar code symbol 1 is output to the high-speed arithmetic circuit 5,
The high speed operation circuit 5 is caused to decode the bar code symbol 1 (step S4). The high-speed arithmetic circuit 5 confirms that the decoding permission flag 7 is set (decoding is permitted) in response to the decoding start signal, and then, from the image of the barcode symbol 1 fetched in the frame memory 4, the barcode symbol concerned. Decode the information in. Further, the high speed operation circuit 5 checks the decoding result (step S5). This decoding content check is only for confirming the decoding result (JAN / UP
C / EAN code, ITF ((lnterleaved 2 of 5) code, CODE39, NW-7 code, CODE12
8, etc.), but with error correction (PDF41
There are also two-dimensional bar code symbols (7, DATA CODE, etc.). Then, the high-speed arithmetic circuit 5 outputs the decoding and check completion signal of the barcode symbol 1 including the information of the check result to the CPU 8.

Here, the CPU 8 judges the decoding and check end signal from the high-speed operation circuit 5 (step S6), and when the decoding is not correctly performed, the process returns to the step S1 and the image capturing is repeated again. .. Also, when the decoding is successful, the CPU8
Outputs a decode result holding signal to the high speed arithmetic circuit 5. The high-speed operation circuit 5 temporarily stores the decoded contents in the decoding result storage memory 6 and clears the decoding permission flag 7 (prohibits decoding) according to the decoding result holding signal (step S7).

Next, the CPU 8 takes out the information recorded in the bar code symbol 1 from the decoding result storage memory 6, controls the host interface circuit 9, and transfers the information to a host computer (not shown) (step S8). ..

The subsequent processing is the "double reading prevention" function part. That is, the CPU 8 outputs the image capture start signal to the video circuit 3 again to the frame memory 4 to capture the image (step S9). After the capture of this image is completed, the high speed arithmetic circuit 5 outputs the barcode symbol 1 Presence / absence is detected (step S10). Here, when the bar code symbol 1 exists in the image captured in the frame memory 4, it is confirmed that the decoding permission flag 7 is cleared (step S11), and the image capturing in step S9 is repeated. That is, when the barcode symbol 1 is still present after the transfer to the host is completed, it is determined that the barcode symbol 1 that has been transferred to the host has not been removed from the reading device, and I am trying not to proceed to the processing of.

On the other hand, when the bar code symbol 1 does not exist (step S11), the CPU 8 again outputs an image capture start signal to the frame memory 4 to the video circuit 3 to capture the image (step S12). After the image is captured, the high speed operation circuit 5 detects the presence or absence of the barcode symbol 1 (step S13). Here, when the bar code symbol 1 is present in the image captured in the frame memory 4, it is confirmed that the decode permission flag 7 is cleared (step S14), and the image capturing in step S9 is repeated. That is, steps S12 to S14
As a result, the same processing as the processing of steps S9 to S11 is repeated.

When it is determined in step S14 that the bar code symbol 1 does not exist, the CPU 8 sets the decode permission flag 7 (step S15). That is, the decoding permission flag 7 is set when the bar code symbol 1 is not present in the image captured in the frame memory 4 twice in a row. Then, the process returns to step S1 and the above-described process is repeated.

Here, in this embodiment, when the bar code symbol 1 does not exist in the image captured twice in the continuous frame memory 4, it is determined that the bar code symbol 1 has been removed, and the decoding permission flag 7 is set. However, if it does not exist even once, it means that the barcode symbol 1 has been removed and the decoding permission flag 7 is set.
Even if this is set, the function of "preventing double reading" can be fulfilled. As in this embodiment, when it is determined that the decoding permission flag 7 does not exist twice consecutively, the decoding permission flag 7
When the reading device or the bar code symbol 1 vibrates for some reason, if the image is taken into the frame memory 4 at that timing, the bar code symbol 1 is not removed. Even when it is determined that the barcode symbol 1 does not exist, and further during the removal operation, that is, when the barcode symbol 1 is being moved, the image is blurred and it is determined that the barcode symbol 1 does not exist. However, if the one-sided bar code symbol 1 stops during this process, it will be decoded twice even if it is a bar code symbol 1 that has already been decoded, that is, twice even if it is read twice. Since reading can be prevented, reliability is improved. Furthermore, the effect is not limited to two consecutive times, and the same effect can be obtained by three times or more.

In order to avoid the above-mentioned fear, the reading cycle from the acquisition of the image of the barcode symbol 1 into the frame memory 4 to the determination of the presence or absence of the barcode symbol 1 is actually closely related. Have. That is, if this read cycle is too long, step S9
The barcode symbol 1 is exchanged between the capture in 1 and the capture in step S12, and the barcode symbol 1 which has not been decoded yet is not decoded. Therefore, in this embodiment, this read cycle is set to about 0.3 seconds.

Further, instead of detecting the bar code symbol 1 from the sequentially captured images as in the above embodiment, for example, the frame memory 4 has a capacity of two screens and the images are captured on each screen at a predetermined time interval. Even if the decoding permission flag 7 is set when the barcode symbol 1 is not detected on both screens, the same effect can be obtained.

In the above embodiment, the kind of bar code symbol to be read is not particularly limited, but the method of detecting the bar code symbol 1 is JAN / U.
PC / EAN code, ITF (lnterleaved 2 of 5) code, CODE39, NW-7 code, CODE12
It suffices to use the method of detecting each bar code such as No. 8, etc., and the two-dimensional bar code symbol (CODE 16K, CO
For DE49, PDF417, DATA CODE, etc.), there is no problem if the detection method of each bar code is used.
As described above, the embodiment is not limited to the type of barcode symbol, but is particularly effective for a two-dimensional barcode symbol having a long reading time.

As described above, in the present embodiment, the "double reading prevention" function can be realized only by detecting the presence or absence of the symbol instead of decoding the bar code symbol 1, so the processing speed is sufficiently high. That is, since the symbol detection processing is always necessary prior to the decoding processing of the barcode symbol 1, in the present embodiment, the time until the symbol detection processing is performed is sufficient.
Conventionally, in addition to this time, time is required until the decoding process is further performed. In addition, even if the sheet on which the bar code symbol 1 is recorded is left behind, it will not be "read twice" and no additional parts such as switches are used, so it is a very preferable method from the viewpoint of the number of parts and operability. It can be said that

Further, as described above, when the bar code symbol 1 does not exist in the images successively fetched into the frame memory 4 twice, it is determined that the bar code symbol 1 has been removed, and the decoding permission flag 7 is set. Therefore, if the reading device or the bar code symbol 1 vibrates for some reason, if an image is taken into the frame memory 4 at that timing,
Even if the bar code symbol 1 is not removed, it is determined that the bar code symbol 1 does not exist, and further, during the removal operation, that is, when the bar code symbol 1 is being moved, the image blurs and the bar code symbol 1 is removed. Although it is determined that the symbol 1 does not exist, if the barcode symbol 1 for a part of the code stops in the middle of this, it is decoded again, that is, read twice even though the barcode symbol 1 has already been decoded. It will not be lost.

[0028]

As described in detail above, according to the present invention,
It is possible to provide a barcode symbol reading device having a reliable "double reading prevention" function.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flow chart for explaining the operation of the embodiment.

[Explanation of symbols]

1 ... Bar code symbol, 2 ... Video camera, 3 ... Video circuit, 4 ... Frame memory, 5 ... High-speed arithmetic circuit, 6 ...
Decoding result storage memory, 7 ... Decoding permission flag, 8
... CPU, 9 ... Host interface circuit.

Claims (1)

[Claims] 1. An image pickup unit for picking up an image of a bar code including a bar and a space, a bar code symbol detection unit for detecting the presence or absence of a bar code symbol from an output signal of the image pick-up unit, and a bar code symbol decoding permission. / State holding means for holding state information indicating a non-permitted state, and the state imaged by the image capturing means when the state information held in the state holding means indicates that the decoding of the bar code symbol is permitted. After decoding the barcode symbol decoding means for interpreting the contents of the barcode symbol from the image of the barcode symbol, and decoding the barcode symbol by the barcode symbol decoding means, the contents of the state information in the state holding means are not decoded. Then, the barcode symbol detection means sets at least 1 When the bar code symbol can not be detected, reading bar code symbols and control means, characterized by comprising comprises a to which the contents of in the state information and the decoding permission state to the state holding means device.