JPH10198753A - Two-dimensional code reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-dimensional(2D) code reader that can read bast while suppressing the loss of time to the minimum when reading of image data has to be tried again. SOLUTION: A CCD can perform processing M2 and M3 for detecting the next 2D image without waiting for judging processing S1 or decoding processing D1 due to a control circuit and storing it in the other image memory and address memory which are not processing objects. Therefore, even when the reading of 2D code is failed by any factor, the image is detected before the failure becomes clear by the judging/decoding processing of control circuit so that the judging/decoding processing of the next frame can be speedily started and the control circuit can repeat the judging/decoding processing at a high speed. Accordingly, the high-speed read of 2D code is enabled while suppressing the loss of time caused by the failure of read to the minimum. As a result, the conveying speed of load can be accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional code for reading data represented by a binary code and reading a two-dimensional code arranged as a pattern on a two-dimensional matrix.
The present invention relates to a dimension code reader.

[0002]

2. Description of the Related Art A two-dimensional code can record a larger amount of information and has a two-dimensional spread as compared with a bar code. Therefore, it takes a longer time to read image data. As an example of such a two-dimensional code reading device, there is one described in Japanese Patent Application Laid-Open No. 8-180125.

[0003] The two-dimensional code reading device has a configuration as shown in FIG. 9 and reads a two-dimensional code in a procedure as shown in FIG. That is, upon receiving an image signal from the CCD sensor 502 that has detected the image of the two-dimensional code, the binarization circuit 504 binarizes the image at a predetermined reference level, and temporarily converts the binarized image data into an image memory 506.
After that, the control circuit 508 decodes the two-dimensional code based on the image data stored in the image memory 506. The image memory 506 stores binarized data at addresses corresponding to the two-dimensional position of the image by the clock circuit 510 and the address setting circuit 512.

In order to execute decoding of a two-dimensional code, it is necessary to determine the position of the two-dimensional code. In the prior art, as one of the methods, a positioning symbol having a characteristic shape is first used. To check for the presence of
When the image data near the center of the positioning symbol is sent to the image memory 506, the change point detection circuit 514
And a ratio detection circuit 516 for detecting a specific dimensional ratio. Each time, the address of the image memory 506 in which the positioning symbol is stored is stored in the address storage memory 5.
18 is stored. Therefore, the control circuit 508
Inspects the image data near the address of the positioning symbol preferentially.

When it is determined that the positioning symbol exists, the control circuit 508 determines that the number of the positioning symbol is a predetermined number, for example, three.
Check if it is an individual. When the number of positioning symbols is three, the control circuit 508 determines the position of the two-dimensional code by obtaining the center of each positioning symbol, and then decodes the area where the data is recorded.

When the number of positioning symbols is not three, the threshold value as a reference for binarizing image data is not appropriate for the brightness of an image of a two-dimensional code. Since it is determined that the image data does not correctly represent the image of the two-dimensional code, the control circuit 508 stops the data processing and executes the detection of the image data from the CCD sensor again.

FIG. 10B shows an example in which the first and second image data readings have failed, and the two-dimensional code has been correctly read in the third image data detection.

[0008]

However, compared to a bar code or the like, a two-dimensional code has a large amount of image data, and if reading of the image data fails, a large amount of time is lost. In fact, due to various causes, the reading of the two-dimensional code is not successful once, and the reading is repeated twice or three times at a considerable frequency.

For this reason, when the two-dimensional code attached to the baggage being transported is read and the transport control is performed based on the information, even if the reading of the two-dimensional code fails, there is a time margin for re-reading. It is necessary to convey at a speed with the two-dimensional code, but the disadvantage that the time required for reading the image data is long,
There have been inconveniences such as the need to keep the transport speed low.

The present invention minimizes the time loss that occurs when re-reading of image data occurs,
An object of the present invention is to provide a two-dimensional code reader capable of high-speed reading.

[0011]

Means for Solving the Problems and Effects of the Invention Here, one or more inventions are described, each having the structure and effect described below. 2 of the present invention
The two-dimensional code reader is a two-dimensional code reader for reading data represented by a binary code into cells and reading a two-dimensional code arranged as a pattern on a two-dimensional matrix. Two-dimensional image detecting means for detecting, a plurality of image storing means for storing a two-dimensional image detected by the two-dimensional image detecting means for each frame, and one image storing means from among the plurality of image storing means Sequentially, and in the selected image storage means, an image storage control means for storing a two-dimensional image repeatedly detected from the two-dimensional image detection means, and in the order stored,
Decoding means for reading two-dimensional image data from the plurality of image storage means and decoding a code represented by the two-dimensional image data.

The two-dimensional image detection means repeatedly detects a two-dimensional image, and the image storage control means stores the repeatedly obtained two-dimensional image in a plurality of image storage means. At the time of this storage, one image storage means is sequentially selected from a plurality of image storage means, and a two-dimensional image is stored in the selected image storage means. That is, consecutive frames are not stored in the same image storage unit.

Thus, even if the two-dimensional image detection means repeatedly detects an image, the decoding means can store the two-dimensional image data while the image storage control means stores the image in another image storage means. Image storage means
Decryption processing can be performed.

Therefore, the two-dimensional image detecting means can detect the next two-dimensional image without waiting for decoding by the decoding means, and can store the next two-dimensional image in the image storage means which is not targeted for decoding at that time. For this reason, even if the reading of the two-dimensional code fails due to some cause, for example, disturbance light or noise, the next two-dimensional image data can be read without waiting until the failure is determined by the decoding means. Since it is stored in another image storage means, the decoding means can quickly proceed to the decoding processing of the two-dimensional image of the next frame without a large loss time.

Therefore, even when the package to which the two-dimensional code is attached is moving at a high speed, the reading process can be repeated at a high speed based on the repeatedly obtained image.
Even when re-reading of two-dimensional image data due to decoding failure occurs, the loss of time that occurs can be minimized, and high-speed reading of two-dimensional codes becomes possible.

As a result, it is possible to increase the transport speed of the load. Further, a positioning symbol pattern detecting means for detecting the presence of a predetermined positioning symbol pattern from the two-dimensional image detected by the two-dimensional image detecting means, and a positioning symbol pattern detected by the symbol pattern detecting means. A plurality of symbol pattern storage means for storing the position for each frame, and the decoding means, based on the position of the pattern of the positioning symbol stored in the symbol pattern storage means, in the order of storage, It is preferable in terms of high-speed processing of the decoding itself that the two-dimensional image data is read from the plurality of image storage units and the code represented by the two-dimensional image data is decoded.

The image storage control means includes a binarization processing means for binarizing a two-dimensional image repeatedly detected by the two-dimensional image detection means using a threshold value, and the plurality of image storage means. And a storage processing means for sequentially selecting one image storage means from among the storage means and storing the two-dimensional image binarized by the binarization processing means in the selected image storage means. It can be.

As the binarization processing means, 2
The two-dimensional image repeatedly detected by the two-dimensional image detecting means may be configured to be binarized using a threshold value that changes every frame. With this configuration, for example, the illumination light to the two-dimensional code changes,
Even if reading failure due to an inappropriate threshold for binarizing a two-dimensional image occurs, the two-dimensional image that is repeatedly detected is binarized while changing the threshold. Binarization is appropriately performed with a threshold value. In addition, the above-described operation can minimize the time loss that occurs, thereby enabling high-speed reading of the two-dimensional code.

The binarization processing means binarizes the two-dimensional image repeatedly detected by the two-dimensional image detection means using different thresholds set according to the stored image storage means. It may be configured as follows. The same effect as in the case of binarization using the threshold value that changes for each frame described above is obtained.

Further, the binarization processing means may use, for example, a smoothing process on a two-dimensional image repeatedly detected by the two-dimensional image detection means, by using a signal of the two-dimensional image, in addition to using a fixed threshold value. The binarization may be performed using the threshold value obtained by the above. In this case, the speed of following the two-dimensional image signal by the smoothing process may be changed for each frame. As described above, even when the speed of the following of the threshold value is changed, a similar effect can be obtained as an effect when the illumination light to the two-dimensional code changes.

The same applies to a configuration in which the speed of following the two-dimensional image signal by the smoothing process is changed in accordance with the stored image storage means. Further, the two-dimensional code reading device includes a two-dimensional image detection unit that detects a two-dimensional image, a plurality of image storage units that store the two-dimensional image detected by the two-dimensional image detection unit for each frame,
Binarization processing for obtaining a plurality of two-dimensional image data by binarizing the same frame of the two-dimensional image repeatedly detected by the two-dimensional image detection unit using each of a plurality of threshold values of the image storage unit Means, storage processing means for storing a plurality of two-dimensional image data obtained by binarization by the binarization means in the plurality of image storage means, respectively, and two-dimensional image data sequentially from the plurality of image storage means. Decoding means for reading out the image data and decoding the code represented by the two-dimensional image data; and when the decoding means has finished decoding the two-dimensional image data stored in all the image storage means, An image detection control unit for causing the two-dimensional image detection unit to detect the next image may be provided.

That is, in this two-dimensional code reader, one two-dimensional image data is stored in a plurality of image storage means.
It is binarized at different thresholds and stored. Therefore,
Since the decoding means stores the two-dimensional image data at once in a plurality of image storage means, it becomes possible to continuously process the two-dimensional image data. And 2 each
Since the thresholds for the binarization are different, even if the reading of the two-dimensional image data binarized by one threshold has failed, the probability of succeeding the decryption by another threshold is very high. Therefore, 2
Reading of the dimensional code can be performed at high speed.

Also in this case, a configuration is provided in which the above-mentioned positioning symbol pattern detection means and a plurality of symbol pattern storage means are provided, and the decoding means decodes the code represented by the two-dimensional image data based on the position of the pattern of the positioning symbol. The same effect can be obtained.

[0024] As the binarization processing means, the smoothing processing in which the speed of following the signal of the two-dimensional image is changed according to the stored image storage means is performed on the signal of the two-dimensional image. The same frame of the two-dimensional image repeatedly detected by the two-dimensional image detecting means may be binarized using the threshold value obtained by the above to obtain a plurality of two-dimensional image data. A similar effect is obtained as an effect when the illumination light to the dimensional code changes.

When the decoding of the two-dimensional image data stored in one of the image storage means is completed, the decoding means determines that the next two-dimensional image has not been detected by the two-dimensional image detection means. May be configured to wait for the detection. Further, an image detection control means for instructing the two-dimensional image detection means to detect the next image when the decoding of the two-dimensional image data stored in all the image storage means is completed is provided. May be.

Also in this case, a configuration is provided in which the above-mentioned positioning symbol pattern detection means and a plurality of symbol pattern storage means are provided, and the decoding means decodes the code represented by the two-dimensional image data based on the position of the pattern of the positioning symbol. The same effect can be obtained.

The decoding means, if the decoding is successful, the two-dimensional image obtained using the same threshold value as when the decoding was successful or the same speed of the smoothing process as when the decoding was successful. May be subjected to learning control so as to be processed first in the decoding of the next plurality of two-dimensional images,
By performing such learning control, reading can be performed more quickly.

The function of executing each unit of the two-dimensional code reader in a computer system is provided, for example, as a program activated on the computer system side. In the case of such a program, for example, a floppy disk, a magneto-optical disk,
It can be used by storing it in a storage medium such as a D-ROM, loading it into a computer system as needed, and starting up. In addition, ROM and backup RAM
The above program may be stored as a storage medium (including a nonvolatile RAM), and the ROM or the backup RAM may be incorporated in a computer system and used.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] FIG. 1 is a block diagram showing a schematic configuration of a two-dimensional code reader 2 to which some of the above-mentioned inventions are applied.

The two-dimensional code reader 2 includes CCDs 4, 2
Value conversion circuit 6, image memories 8, 10, 12, clock signal output circuit 14, address generation circuit 16, change point detection circuit 18, ratio detection circuit 20, address storage memories 22, 2.
4 and 26 and a control circuit 28.

The control circuit 28 includes a CPU, ROM, RA
It is configured as a computer system having M, I / O, and the like.
Each component of the dimensional code reader 2 is controlled. In addition,
The program may be stored in a nonvolatile RAM instead of the ROM.

Here, an example of a two-dimensional code detected by the two-dimensional code reader 2 is shown in FIG. The two-dimensional code 52 is printed on a white mount 53,
It comprises a plurality of positioning symbols 54, a data area 56, and an origin cell Cst. All of them are arranged in a square shape having the same number of cells vertically and horizontally (21 cells × 21 cells). Each cell is selected from two types of cells that are optically different from each other, and is distinguished between white (bright) and black (dark) in the drawings and description. In FIG. 2, the pattern of the data cell in the data area 56 is omitted for convenience.

The positioning symbols 54 are arranged at three of the four vertices of the two-dimensional code 52. The light / dark arrangement of the cells is such that a reduced frame-shaped square 54b composed of a white portion is formed at the center of a frame-shaped square 54a composed of a black portion, and a further reduced square 5 composed of a black portion is formed at the center thereof.
4c is a pattern formed.

The control circuit 28 performs reading control as described below. First, according to an instruction from the control circuit 28, the CCD 4 detects a two-dimensional image of a position where the two-dimensional code 52 passes. When detecting the two-dimensional image, the CCD 4 outputs two-dimensional image data by a signal having multiple levels as shown in FIG. The two-dimensional image data is binarized by the binarization circuit 6 using a threshold value specified by the control circuit 28, and has two levels of 1 (high) / 0 (low) as shown in FIG. Into a signal consisting of

On the other hand, in response to the synchronization pulse output from the CCD 4, the clock signal output circuit 14 outputs a clock pulse finer than the pixels of the two-dimensional image data output from the CCD 4. The address generation circuit 16 counts this clock pulse and generates an address for the image memories 8, 10, and 12. The two-dimensional image data binarized from the binarization circuit 6 is supplied from the control circuit 28 with an address offset value to the address generation circuit 16.
First image memory 8 of image memories 8, 10, and 12
Is generated by the address generation circuit 16 so that the two-dimensional image data is written into the first image memory 8 in 8-bit units.

On the other hand, when the signal from the binarization circuit 6 changes from "1" to "0" or from "0" to "1", the change point detection circuit 18 outputs a pulse to the ratio detection circuit 20. Output a signal. The ratio detection circuit 20 includes a change point detection circuit 18.
Between the pulse signal input from
By counting the clock pulses output from the clock signal output circuit 14, the continuous length of light (1) and the continuous length of dark (0) in the two-dimensional image are obtained. From this length ratio, a pattern corresponding to the positioning symbol 54 of the two-dimensional code 52 is detected.

As shown in FIG. 3A, the light and dark patterns of the scanning lines (a), (b) and (c) of the CCD 4 which cross the substantially center of the positioning symbol 54 at a representative angle are shown in FIG. As shown in (B), all have a structure having the same light-dark component ratio. That is, each scanning line (a), (b), (c) crossing the center of the positioning symbol 54
Is a dark: bright: dark: bright: dark = 1: 1: 3: 1:
It is 1. Of course, the scanning lines (a), (b), (c)
The ratio is also 1: 1: 3:
1: 1. Further, even if the figure of FIG. 3A is arranged on a plane oblique from the CCD 4 side, the light-dark component ratio of the scanning lines (a), (b) and (c) is dark: light: dark:
Light: dark = 1: 1: 3: 1: 1. FIG. 3B
Corresponds to the binarized signal from the binarization circuit 6.

Therefore, the ratio detection circuit 20 detects the light-dark component ratio of "1: 1: 3: 1: 1", and when the ratio is detected, the ratio indicated by the address generation circuit 16 at that timing. The address of the second image memory 8 is 1
The address is stored in the second address storage memory 22.

Therefore, the CCD 4 has two frames for one frame.
When detecting the two-dimensional image data, the first image memory 8 stores the binarized two-dimensional image data. The first address storage memory 22 stores the address when the positioning symbol 54 is detected. The address of the first image memory 8 output from the generation circuit 16 is stored.

When the control circuit 28 determines from the signal from the CCD 4 that the one frame of the first two-dimensional image has been detected by the CCD 4 and output to the binarization circuit 6, the control circuit 28 continues. Then, it instructs the CCD 4 to detect the next one-frame two-dimensional image. Therefore, CC
From D4, the two-dimensional image is repeatedly output to the binarization circuit 6, and the storage processing is performed as described above.

However, every time the control circuit 28 instructs the CCD 4 to detect a two-dimensional image, the control circuit 28 switches the offset value to the address generation circuit 16 and sequentially shifts one by one for each frame.
The image memory for storing the two-dimensional image is switched to the second image memory 8, the second image memory 10, and the third image memory 12. When the storage of the two-dimensional image in the third image memory 12 is completed, the process returns to the first image memory 8, and
Switching is repeated in this order. Similarly, the address storage memories 22 to 26 are switched. Each time the control circuit 28 switches the offset value to the address generation circuit 16, the control circuit 28 also switches the threshold value used for the binarization for the binarization circuit 6. That is, three thresholds having different values are prepared, and the image memory 8 to be stored is prepared.
In this case, three thresholds are selected and switched according to the values of .about.12. As a result, different 2 for each of the image memories 8 to 12
Two-dimensional image data binarized at the binarization level is stored.

The control circuit 28 first stores two-dimensional image data in the first image memory 8 and stores the address of the positioning symbol 54 in the first address storage memory 22. The detection of the next two-dimensional image is instructed, and then the determination / decoding process for the first image memory 8 and the first address storage memory 22 is started.

That is, as shown in the timing chart of FIG. 5A, when the storage processing M1 in the first image memory 8 and the first address storage memory 22, which is performed in hardware, is completed, the instruction of the control circuit 28 is issued. Immediately starts the storage processing M2 in the second image memory 10 and the second address storage memory 24. In parallel with the storage processing M2, the control circuit 28 controls the first image memory 8 and the first To determine whether or not three positioning symbols 54 are present at appropriate positions based on the stored contents.
I do.

If three positioning symbols 54 are properly present in the two-dimensional image data, the control circuit 28 subsequently proceeds to the first image memory 8 based on the position of the positioning symbols 54. The position of each cell in the two-dimensional image data is determined, 1/0 is determined from the position, and a decoding process D1 for reading the code content represented by the two-dimensional code 52 is performed.

During the decryption processing D1, the storage processing M2 to the next second image memory 10 and the second address storage memory 24 has been completed, but the second image memory 10 and the second The determination process S2 for the address storage memory 24 is performed after the completion of the decryption process D1 as shown. Further, the third image memories 12 and 3
The instruction to the CCD 4 for the storage process M3 in the second address storage memory 26 is performed by an interrupt process during the decryption process D1, but the instruction process is a short process and the processing speed of the decryption process D1 Has little effect on

The example shown in FIG. 5A shows an example in which reading has been successfully performed in the first decryption processing D1, and the two-dimensional image data stored in the storage processing M2, M3, and M11 is stored. Ends only in the determination processes S2, S3, and S11. The execution of the determination processing S2, S3, S11
This is because the two-dimensional image of the two-dimensional code 52 attached to the package and passing in front of the CCD 4 does not end in one frame, but is detected by the CCD 4 for a plurality of frames continuously.

That is, since the positioning symbols 54 are continuously detected in the determination processes S2, S3, and S11 after the success of the decryption process D1, the same two-dimensional code 5 is obtained.
2 can be determined to continue to be captured.
2, S3 and S11 are performed, and decryption processing D2, D3 and D1 is performed.
1 is not performed.

After that, based on the two-dimensional image data obtained by the storage processing, the decoding processing is performed until the positioning symbol 54 is detected for a certain number of frames for a while in the determination processing. After. for a while,
If the positioning symbol 54 is not detected, it can be seen that the baggage to which the two-dimensional code 52 has been attached has passed the CCD 4 and is no longer detected. This is because it can be determined that the two-dimensional code 52 comes before the CCD 4 and is detected by the CCD 4.

The broken line indicates the flow of the storage process, and the dashed line indicates the flow of the determination / decoding process by the control circuit 28. In FIG. 5B, in the determination processes S1 and S2, three suitable positioning symbols 54 cannot be detected, and the determination is performed on the third image memory 12 and the third address storage memory 26. In the third determination processing S3, an appropriate 3
The three positioning symbols 54 are detected, and the decoding process D3 is performed.
Shows an example of successful decoding. FIG. 10B, which is shown as a conventional technique, is also an example in which decoding was successfully performed in the third decoding process D3, but FIG.
In the case of, it can be seen that the processing time for the determination processes S1 and S2 is shorter.

FIG. 5 (c) shows an example in which the bag to which the two-dimensional code 52 is attached does not pass in front of the CCD 4 and three suitable positioning symbols 54 cannot be detected in succession. In the first embodiment, as described above, the CCD 4 repeatedly detects the two-dimensional image according to the instruction of the control circuit 28 and sequentially and cyclically detects the image memories 8 to 12.
Then, the address storage memories 22 to 26 are selected, the two-dimensional image is stored in the selected image memories 8 to 12, and the addresses of the positioning symbols are stored in the address storage memories 22 to 26. That is, frames that are repeatedly acquired are not stored in the same image memories 8 to 12 and the address storage memories 22 to 26.

Thus, even when the CCD 4 repeatedly detects an image, the control circuit 28 operates while the other image memories 8 to 12 and the address storage memories 22 to 26 store the image in the address generation circuit 16. The determination / decoding process can be performed on the image memories 8 to 12 and the address storage memories 22 to 26 in which the two-dimensional image data is already stored.

Therefore, the CCD 4 detects the next two-dimensional image without waiting for the judgment and decoding by the control circuit 28, and detects the next two-dimensional image.
To 12 and the address storage memories 22 to 26. Therefore, even if the reading of the two-dimensional code 52 fails due to some cause, for example, disturbance light, noise, or the like, the control circuit 28 does not wait until the failure is found by the determination / decoding process without the next time. Since the two-dimensional image data is taken into the other image memories 8 to 12 and the address storage memories 22 to 26, the control circuit 28 can quickly determine the two-dimensional image of the next frame without a large loss time.・ We can move on to the decryption process.

Therefore, even when the baggage to which the two-dimensional code 52 is attached is moving at high speed, the control circuit 28 can repeat the judgment / decoding processing at high speed based on the repeatedly acquired images, When the re-detection of the two-dimensional image data due to the failure of the two-dimensional image data occurs, the time loss that occurs can be minimized, and the two-dimensional code 5
2 can be read at high speed. As a result, it is possible to increase the transport speed of the load.

The two-dimensional code reader 2 according to the first embodiment binarizes a two-dimensional image repeatedly detected from the CCD 4 using different thresholds according to the image memories 8 to 12. It instructs the binarization circuit 6. With this configuration, for example, even if the illumination light to the two-dimensional code 52 changes and a threshold value for binarizing the two-dimensional image becomes inappropriate, so that decoding failure occurs, Since the two-dimensional image that is repeatedly detected is binarized while changing the threshold, binarization is appropriately performed at one of the thresholds. Moreover, even if the decoding process is repeated in this manner, as described above, the determination and decoding process can be performed during the storage process, so that the time loss that occurs can be minimized.

It is to be noted that the threshold value can be binarized by switching the threshold value for each frame of the two-dimensional image obtained from the CCD 4 without having to correspond to the image memories 8 to 12. Produces an effect. Here, the CCD 4 and the control circuit 28 for instructing the CCD 4 to perform detection correspond to two-dimensional image detection means, the image memories 8 to 12 correspond to a plurality of image storage means, and the binarization circuit 6 performs binarization processing. The address generation circuit 16 and the address generation circuit 1
The control circuit 28 for giving an offset value to the memory 6 corresponds to storage processing means, the control circuit 28 corresponds to decoding means, the change point detection circuit 18 and the ratio detection circuit 20 correspond to positioning symbol pattern detection means, and an address storage memory. 22-2
Reference numeral 6 corresponds to a plurality of symbol pattern storage means.

[Second Embodiment] FIG. 6 is a block diagram showing a schematic configuration of a two-dimensional code reader 102 to which some of the inventions described above as the second embodiment are applied. The two-dimensional code reader 102 includes a CCD 104, a binarization circuit 1
06a, 106b, 106c, image memories 108, 11
0, 112, clock signal output circuit 114, address generation circuits 116a, 116b, 116c, change point detection circuits 118a, 118b, 118c, ratio detection circuit 120a,
120b, 120c, address storage memories 122, 12
4, 126 and a control circuit 128.

Regarding the hardware part of each configuration,
CC of the two-dimensional code reader 2 according to the first embodiment
D4, binarization circuit 6, image memories 8, 10, 12, clock signal output circuit 14, address generation circuit 16, change point detection circuit 18, ratio detection circuit 20, address storage memory 2
2, 24, 26 and the control circuit 28,
Detailed description is omitted.

The difference from the two-dimensional code reader 2 of the first embodiment is that, in terms of hardware, the two-dimensional code readers 106a to 106a
6c, address generation circuits 116a to 116c, change point detection circuits 118a to 118c, and ratio detection circuits 120a to 120c.
120c are provided three each, and the image memory 10
8, 110, 112 and the address storage memory 122,
In addition to 124 and 126, each is a pair.

As software, processing as shown in the timing chart of FIG. 7 is executed. That is, the control circuit 1
Reference numeral 28 denotes three image memories 1 as shown in FIG.
08-112 and three address storage memories 122-
The storage processes M1, M2, and M3 in the memory 126 are performed simultaneously and in parallel. As soon as the storage processes M1, M2, and M3 are completed, the control circuit 128 causes the first image memory 108 and the first address storage memory 122, and the positioning symbol 54 is
A determination process S1 is performed to determine whether three exist at appropriate positions.

If three positioning symbols 54 are properly present in the two-dimensional image data, the control circuit 128
Next, based on the position of the positioning symbol 54,
The position of each cell of the two-dimensional code 52 in the two-dimensional image data of the first image memory 108 is determined, and 1 /
By determining 0, a decoding process D1 for reading the code content represented by the two-dimensional code 52 is performed.

The example shown in FIG. 7A shows an example in which the decryption was successful in the first decryption processing D1.
2, for the two-dimensional image data stored in M3,
No processing is performed. Then, again, the three image memories 108 to 112 and the three address storage memories 12
The storage processes M11, M12, and M13 to the memory devices 2 to 126 are performed simultaneously and in parallel. This storage processing M11, M12, M1
Immediately after the step 3, a determination process S11 is performed for the first image memory 108 and the first address storage memory 122 to determine whether three positioning symbols 54 are present at appropriate positions. If it is determined that the same two-dimensional code 52 is detected, it can be determined that the same two-dimensional code 52 is continuously detected, so that the storage processing to the three image memories 108 to 112 and the three address storage memories 122 to 126 is further performed. M21, M22 and M23 are performed simultaneously and in parallel. FIG. 7A shows this state.

If it is determined in the determination processing S11 that the first image memory 108 and the first address storage memory 122
If it is determined that three positioning symbols 54 are not present at appropriate positions for the second image memory 110 and the second address storage memory 124, three positioning symbols 54 are located at appropriate positions. It is determined whether it exists. If it is determined that the two-dimensional code 52 exists, it can be determined that the same two-dimensional code 52 is continuously detected.
08-112 and three address storage memories 122-
The storage processes M21, M22, and M23 to the memory 126 are performed simultaneously and in parallel.

If the second image memories 110 and 2
When it is determined that three positioning symbols 54 are not present at appropriate positions in the third address storage memory 124, the positioning symbols 54 are determined in the third image memory 112 and the third address storage memory 126. It is determined whether three exist at appropriate positions. Here, if it is determined that it exists,
Since it can be determined that the same two-dimensional code 52 is continuously detected, the three image memories 108 to 112 and 3
Storage processing M in one address storage memory 122 to 126
21, M22 and M23 are performed in parallel.

FIG. 7B shows the judgment processes S1 and S2.
, The appropriate three positioning symbols 54 cannot be detected, and in the third determination processing S3 performed on the third image memory 112 and the third address storage memory 126, the appropriate three An example is shown in which three positioning symbols 54 have been detected and have been successfully decoded in the decoding process D3. Compared with the conventional example of FIG. 10A, the time for two storage processes M2 and M3 is shorter. FIG. 5 (c)
Indicates that the bag to which the two-dimensional code 52 is attached does not pass in front of the CCD 4 and three suitable positioning symbols 5
4 shows an example in which detection cannot be performed. Therefore, always 3
The three determination processes S1 to S3 and S11 to S13 are continuously performed.

In the second embodiment, the CCD 1
04 repeatedly detects a two-dimensional image in accordance with an instruction from the control circuit 128, and simultaneously binarizes one frame of the two-dimensional image at different threshold values in the binarization circuits 106a to 106c, Each image memory 108-1
12 and furthermore, each of the address storage memories 122-1
26 also stores the address of the positioning symbol 54.

Thus, a two-dimensional image obtained by binarizing an image detected by the CCD 104 at a time with different threshold values can be sequentially processed.
It is not necessary to detect from D104, and the reading process can be performed at high speed. For this reason, even if reading of the two-dimensional code 52 from one two-dimensional image data fails due to some cause, for example, disturbance light or noise, it is possible to immediately proceed to processing of a two-dimensional image having a different threshold value. ,
The control circuit 128 can quickly perform a two-dimensional image determination / decoding process without a large loss time.

Therefore, even when the package to which the two-dimensional code 52 is attached is moving at a high speed, the control circuit 128 can repeat the determination / decoding processing at a high speed based on the repeatedly acquired images, When the re-detection of the two-dimensional image data occurs due to the failure, the time loss that occurs can be minimized, and the two-dimensional code 52 can be read at high speed. As a result, it is possible to increase the transport speed of the load.

Here, the CCD 104 and the CCD 104
The control circuit 128 for instructing the detection corresponds to two-dimensional image detection means, the image memories 108 to 112 correspond to a plurality of image storage means, the binarization circuits 106a to 106c correspond to binarization processing means, Address generation circuits 116a to 116
c and a control circuit 128 for giving an offset value to the address generation circuits 116a to 116c correspond to the storage processing means, the control circuit 128 corresponds to the decoding means, and the change point detection circuits 118a to 118c and the ratio detection circuits 120a to 120c.
0c corresponds to the positioning symbol pattern detecting means, and the address storage memories 122 to 126 correspond to a plurality of symbol pattern storing means.

[Others] As the binarizing circuit 6 in the first embodiment, a comparator 2 as shown in FIG.
02, the input signal from the CCD 4 and the control circuit 28
By comparing the instruction signal representing the threshold value from the analog signal with the analog voltage signal converted by the D / A converter 204, the signal can be binarized. The control circuit 28 may switch the threshold value with an instruction signal according to the image memories 8 to 12 and the address storage memories 22 to 26 in which data is stored at that time. Instead of switching the threshold value according to the image memories 8 to 12 and the address storage memories 22 to 26, the threshold value may be switched for each frame detected by the CCD 4.

In the first embodiment, the two-dimensional image detection of the CCD 4 is started according to an instruction from the control circuit 28. However, the storage processing M1, M2, M3, M11,...
May be performed continuously, and even if there is no instruction from the control circuit 28, the CCD 4 itself or a specially provided hardware configuration may be used so that the CCD 4 repeatedly detects a two-dimensional image.

The binarization circuits 106a to 106c according to the second embodiment may be those shown in FIG. 8A, but may be fixed value thresholds which are not instructed by the control circuit 128. For example, as shown in FIG. 8C, the comparator 2 compares a voltage output obtained by dividing the power supply voltage by the two resistors 224 and 226 with an input signal from the CCD 104.
A configuration for comparison at 22 may be used. In this case, the resistors having different ratios of the resistance values of the two resistors 224 and 226 may be used so that the divided voltages are different by the number of the binarization circuits 106a to 106c.

In the first and second embodiments, the binarization circuits 6, 106 a to 106 c compare the threshold value set to a predetermined value with the input signal from the CCD 4, 104. Instead, as shown in FIG. 8 (b), a threshold value obtained by subjecting an input signal from the CCDs 4 and 104 to a smoothing process, that is, a time averaging process, by a resistor 214 and a capacitor 216,
The signal may be binarized by comparing the input signal from the comparator 04 with the comparator 212. Resistor 214 and capacitor 21
The control circuits 28 and 128 provide the image memories 8 to 12, 108 to 112 and the address storage memories 22 to 26 and 122 to 126 by adjusting a plurality of impedances with different tracking speeds. , Or by switching every frame.

The image memories 8 to 12, 108 to 11
2 and address storage memories 22 to 26, 122 to 12
6, when the reading (judgment processing and decoding processing) is successful, instead of switching the threshold value or the following speed in accordance with each frame or every frame, the same threshold value as when reading was successful or decoding succeeded Learning control may be performed so that a two-dimensional image obtained by using the same speed of the smoothing process as when the first processing is performed in the next determination and decoding of a plurality of two-dimensional images. . For example, in the first embodiment, in the first storage process M1 of the three storage processes M1, M2, and M3, it can be realized by using the learned threshold value or the following speed. Also, in the second embodiment, of the storage processes M1, M2, and M3, the one that performs the determination process and the decryption process first and selects the one that has been subjected to the binarization process at the learned threshold value or the following speed. Can be realized by: By performing such learning control, reading can be performed more quickly.

In the first and second embodiments, 3
Although two image memories 8 to 12, 108 to 112 and address storage memories 22 to 26, 122 to 126 are used,
As long as the speed of the judgment process and the decoding process is high, two image memories and two address storage memories may be used. If the speed of the judgment process and the decoding process is low, four or more image memories and address storage memories may be used.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a two-dimensional code reader according to a first embodiment.

FIG. 2 is an explanatory diagram of a configuration of a two-dimensional code.

FIG. 3 is an explanatory diagram of light / dark detection when a positioning symbol is scanned.

FIG. 4 is an explanatory diagram of output signals of a CCD and a binarization circuit.

FIG. 5 is a timing chart illustrating a processing procedure of the two-dimensional code reader according to the first embodiment.

FIG. 6 is a block diagram illustrating a schematic configuration of a two-dimensional code reader according to a second embodiment;

FIG. 7 is a timing chart illustrating a processing procedure of the two-dimensional code reader according to the second embodiment.

FIG. 8 is an explanatory diagram of a configuration of a binarization circuit.

FIG. 9 is a block diagram illustrating a schematic configuration of a conventional two-dimensional code reader.

FIG. 10 is a timing chart showing a processing procedure of a conventional two-dimensional code reader.

[Explanation of symbols]

2 2D code reader 4 CCD 6
Binarization circuit 8, 10, 12 image memory 14 clock signal output circuit 16 address generation circuit 18 change point detection circuit
20 ratio detection circuit 22, 24, 26 address storage memory 28 control circuit 52 two-dimensional code 54 positioning symbol 102 two-dimensional code reader 104 CCD 106a, 106b, 106c binarization circuit 108 110, 112: Image memory 114: Clock signal output circuit 116a, 116b, 116c: Address generation circuit 118a, 118b, 118c: Change point detection circuit 120a, 120b, 120c: Ratio detection circuit 122, 124, 126 ... Address storage memory 12
8 Control circuit 202 Comparator 204 D / A converter 212
Comparator 214: resistor 216: capacitor 222: comparator 224, 226: resistor

Claims (12)

[Claims] 1. A two-dimensional code reader for converting data represented by a binary code into cells and reading a two-dimensional code arranged as a pattern on a two-dimensional matrix, wherein a two-dimensional image is repeatedly detected. Two-dimensional image detecting means, a plurality of image storing means for storing the two-dimensional image detected by the two-dimensional image detecting means for each frame, and one image storing means out of the plurality of image storing means. An image storage control means for sequentially selecting and storing a two-dimensional image repeatedly detected by the two-dimensional image detection means in the selected image storage means; and Decoding means for reading out the two-dimensional image data and decoding the code represented by the two-dimensional image data. 2. A positioning symbol pattern detecting means for detecting the presence of a predetermined positioning symbol pattern from a two-dimensional image detected by the two-dimensional image detecting means; A plurality of symbol pattern storage means for storing the position of the pattern of the positioning symbol for each frame; andthe decoding means stores the position based on the position of the pattern of the positioning symbol stored in the symbol pattern storage means. 2. The two-dimensional code reader according to claim 1, wherein the two-dimensional image data is read from the plurality of image storage units in a given order, and a code represented by the two-dimensional image data is decoded. 3. The image storage control unit includes: a binarization processing unit that binarizes a two-dimensional image repeatedly detected by the two-dimensional image detection unit using a threshold value; Storage processing means for sequentially selecting one image storage means from among them, and storing the two-dimensional image binarized by the binarization processing means in the selected image storage means. The two-dimensional code reader according to claim 1 or 2, wherein: 4. The binarizing processing unit binarizes a two-dimensional image repeatedly detected by the two-dimensional image detecting unit using a threshold value that changes every frame. 3. The two-dimensional code reader according to 3. 5. The binarization processing unit binarizes a two-dimensional image repeatedly detected by the two-dimensional image detection unit using different thresholds set according to the stored image storage unit. 4. The two-dimensional code reading device according to claim 3, wherein: 6. The two-dimensional image processing apparatus according to claim 1, wherein the two-dimensional image repeatedly detected by the two-dimensional image detecting means is binarized using a threshold obtained by smoothing a signal of the two-dimensional image. The two-dimensional code reading device according to claim 3, wherein the two-dimensional code reading device is used. 7. The two-dimensional code reader according to claim 6, wherein the speed of following the signal of the two-dimensional image by the smoothing process is changed for each frame. 8. The method according to claim 6, wherein a speed of following the signal of the two-dimensional image by the smoothing process is changed in accordance with the stored image storage means.
Dimension code reader. 9. A two-dimensional code reader for reading data represented by a binary code into cells and reading a two-dimensional code arranged as a pattern on a two-dimensional matrix, wherein a two-dimensional image is detected. Two-dimensional image detection means; a plurality of image storage means for storing the two-dimensional image detected by the two-dimensional image detection means for each frame; and the same two-dimensional image repeatedly detected by the two-dimensional image detection means A plurality of two-dimensional image data obtained by binarizing the frame using a plurality of types of threshold values of the image storage unit; and a binarization process obtained by the binarization unit. Storage processing means for storing the plurality of two-dimensional image data in the plurality of image storage means, and reading out the two-dimensional image data from the plurality of image storage means in order. Decoding means for decoding the code being decoded, and, when decoding of the two-dimensional image data stored in all the image storage means by the decoding means is completed, causes the two-dimensional image detection means to detect the next image. A two-dimensional code reader, comprising: image detection control means. 10. A two-dimensional code reader for converting data represented by a binary code into cells and reading a two-dimensional code arranged as a pattern on a two-dimensional matrix, and detecting a two-dimensional image. Two-dimensional image detecting means; a plurality of image storing means for storing the two-dimensional image detected by the two-dimensional image detecting means for each frame; and a speed of following a signal of the two-dimensional image is stored. Smoothing processing changed according to the image storage means,
The same frame of the two-dimensional image repeatedly detected by the two-dimensional image detecting means is binarized using a threshold obtained by performing the signal on the two-dimensional image,
Binarization processing means for obtaining a plurality of two-dimensional image data; storage processing means for respectively storing the plurality of two-dimensional image data obtained by binarization by the binarization means in the plurality of image storage means; Decoding means for sequentially reading two-dimensional image data from the plurality of image storage means and decoding the code represented by the two-dimensional image data; and two-dimensional image data stored in all the image storage means by the decoding means. An image detection control means for causing the two-dimensional image detection means to detect the next image when the decoding of the image data is completed. 11. A positioning symbol pattern detecting means for detecting the presence of a predetermined positioning symbol pattern from a two-dimensional image detected by said two-dimensional image detecting means; A plurality of symbol pattern storage means for storing the position of the pattern of the positioning symbol for each frame; andthe decoding means stores the position based on the position of the pattern of the positioning symbol stored in the symbol pattern storage means. 11. The two-dimensional code reader according to claim 9, wherein two-dimensional image data is read from the plurality of image storage units in a given order, and a code represented by the two-dimensional image data is decoded. 12. The decryption means, if the decryption is successful, obtains a two-dimensional image obtained by using the same threshold value as when the decryption was successful or the same smoothing processing speed as when the decryption was successful. The two-dimensional code reader according to claim 3, wherein an image is to be processed first in the next decoding of a plurality of two-dimensional images.