JP2004013260A - Two dimensional code reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two dimensional code reader of which adjustment work can be performed accurately in its installation by transmitting status of its decryption processing to an external device and displaying the status externally and which is capable of coping with aging of a marker to print a code and a label printer and deterioration of a light source. <P>SOLUTION: The two dimensional code reader is capable of transmitting information on a cause of a decryption error to an external device when there occurs a decryption error in a decrypting part that decrypts informationof the two dimensional code. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a two-dimensional code reader that reads a two-dimensional code using an image sensor.
[0002]
[Prior art]
Today, barcodes are widely used as a means of inputting information to computers. In recent years, two-dimensional codes having an information recording density several tens of times higher than barcodes have been widely used in production management systems and distribution management systems in factories. It is beginning to be used for various purposes. Currently, international standardization of two-dimensional codes is being promoted, and further spread is expected in the future.
[0003]
FIG. 5 shows an example of the bar code (a) and the two-dimensional code (b). As shown in the figure, the two-dimensional code (b) records information in the X and Y directions as compared with the bar code (a) recording information only in the X direction. Can be improved. As described above, in the two-dimensional code, information is recorded in the area. Therefore, a sensor that reads the code uses an image sensor in the area. FIG. 6 shows a configuration example of a two-dimensional code reader. 1 is a two-dimensional code, 2 is a light receiving lens that forms an image of the two-dimensional code 1 on the image sensor 3, 3 is an image sensor that converts the image of the two-dimensional code 1 into an electric signal, and 4 is an image. A circuit section for converting an output signal of the sensor 3 into a digital signal; 5, an image memory for storing the output signal of the circuit section 4; A processor 7 is a communication unit for transmitting decoding information of the microprocessor 6 to an external device, and a monitor interface 8 is for transmitting an image captured by the image sensor 3 to an external image monitor. Reference numeral 9 denotes an external display unit for externally displaying information such as completion of decoding, which is constituted by an LED or a buzzer. FIG. 7 shows an example in which the two-dimensional code reader shown in FIG. 6 is installed at a production site. Reference numeral 101 denotes a processed product on which a two-dimensional code 1 is printed. An illumination light source 11 illuminates the two-dimensional code 1. 10 is a two-dimensional code reader. Reference numeral 12 denotes an image monitor that displays an image captured by the image sensor 3 in the two-dimensional code reader 10. Reference numeral 13 denotes an information terminal for processing decoding information and the like from the two-dimensional code reader 10, and a personal computer or a sequencer is used. As shown in FIG. 7, when the two-dimensional reader 10 is installed at the production site, the focus of the light receiving lens 2 and the adjustment of the aperture and the illumination light source 11 are checked while checking the image of the two-dimensional code 1 on the image monitor 12 of FIG. In general, a method of adjusting the amount of light and the irradiation angle and adjusting the installation is performed.
[0004]
[Problems to be solved by the invention]
However, in the installation / adjustment using the image monitor 12, when the two-dimensional code cannot be read, it takes time to elucidate the cause of the decoding error. Since it is unknown, a slight change in conditions after installation, for example, a variation in the printing density of the two-dimensional code 1 may cause frequent reading defects. In addition, even during operation after installation, the reading rate is reduced during operation due to deterioration of printing quality due to the aging of the marker or label printer that prints the two-dimensional code, and deterioration of image contrast due to the decrease in the amount of light of the illumination light source 9. Phenomenon occurs.
[0005]
The present invention solves this problem by transmitting the status of the decoding process of the two-dimensional code reader to an external device, or displaying the status of the decoding process to the outside, thereby making the adjustment work at the time of installation more accurate. It is another object of the present invention to provide a two-dimensional code reader capable of coping with a marker for printing a code, a change over time of a label printer, and deterioration of an illumination light source.
[0006]
[Means for Solving the Problems]
In order to solve such a problem, a first two-dimensional code reader according to the present invention includes a light receiving lens for forming an image of a two-dimensional code on an image sensor, and an image sensor for converting the image of the two-dimensional code into an electric signal. An A / D converter for converting an output signal of the image sensor into a digital signal; an image memory for storing the output signal of the A / D converter; and processing of information in the image memory to obtain information of the two-dimensional code. A decoder for decoding, and a communication unit for transmitting decoding information of the decoder to an external device, and when the decoder fails to decode the information of the two-dimensional code and a decoding error occurs, the cause of the decoding error from the communication unit. The information is transmitted to an external device.
[0007]
A second two-dimensional code reader according to the present invention includes a light receiving lens that forms an image of a two-dimensional code on an image sensor, an image sensor that converts the two-dimensional code image into an electric signal, and an output signal of the image sensor. An A / D converter for converting the signal into a digital signal; an image memory for storing the output signal of the A / D converter; a decoder for processing information in the image memory to decode the two-dimensional code information; When the decoder decodes the information of the two-dimensional code, the contrast value of the pattern of the bright part and the dark part at a predetermined position constituting the two-dimensional code is determined by the communication unit that transmits the decoding information to an external device. The communication unit transmits the dimensional code decoding information to an external device together with the decoding information.
[0008]
The third two-dimensional code reader of the present invention has a display function of comparing the contrast value with a preset value, and displaying the result to an external device when the comparison result is smaller than a predetermined value.
[0009]
The fourth two-dimensional code reader of the present invention has a function of comparing the contrast value with a preset value, and transmitting warning information from the communication unit to an external device when the comparison result is smaller than a predetermined value. It is a thing.
[0010]
A fifth two-dimensional code reader according to the present invention includes a light receiving lens that forms an image of a two-dimensional code on an image sensor, an image sensor that converts the two-dimensional code image into an electric signal, and an output signal of the image sensor. An A / D converter for converting the signal into a digital signal; an image memory for storing the output signal of the A / D converter; a decoder for processing information in the image memory to decode the two-dimensional code information; A communication unit configured to transmit decoding information to an external device, and error correction information calculated by the decoder when decoding the two-dimensional code information is transmitted from the communication unit to the external device together with the two-dimensional code decoding information. Things.
[0011]
The sixth two-dimensional code reader of the present invention has a display function of comparing the error correction information with a preset value, and displaying the error correction information to an external device when the comparison result is larger than a predetermined value.
[0012]
The seventh two-dimensional code reader of the present invention has a function of comparing the error correction information with a preset value, and transmitting a warning information from the communication unit to an external device when the comparison result is larger than a predetermined value. It is provided.
[0013]
As shown in the above configuration, in the first two-dimensional code reader of the present invention, the error determination content of the decoder that has performed the decoding process at the time of the decoding error is transmitted to the external device, so the factor that caused the error is the print quality. It is possible to easily estimate whether the adjustment is an adjustment of an illumination light source or a light receiving lens.
[0014]
Further, in the second and fifth two-dimensional code readers of the present invention, the contrast value of the pattern of the bright part and the dark part at the time of decoding or the error correction information at the time of decoding is transmitted to the external device together with the decoding information. Can be checked, and more accurate installation adjustment can be performed.
[0015]
In the third, fourth, sixth, and seventh two-dimensional code readers of the present invention, the contrast value of the bright part and the dark part of the two-dimensional code at the time of decoding processing or the margin of error correction information is compared and determined for each decoding processing. However, since the result is communicated or displayed to an external device, a decrease in the reading rate during operation can be prevented in advance.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a two-dimensional code reader according to an embodiment of the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a flowchart showing one embodiment of the first two-dimensional code reader of the present invention. The microprocessor 6 processes the image information stored in the image memory 5 and performs a binarization process for separating the image information into a bright part and a dark part (processing a). If a bright part and a dark part cannot be determined and a binarization error occurs, the binarization error information is transmitted to the external device, and the processing is completed (processing a, c). If the binarization has been performed normally, a two-dimensional code position detection process is performed (processes a and d). The two-dimensional code position detection process is a process of detecting three rectangular position detection patterns in the example of the two-dimensional code shown in FIG. 2, for example. If the position cannot be detected, the position detection error information is transmitted to the external device and the process is completed (processes d and e). If the position is detected normally, an error correction process using a Reed-Solomon code is performed (processes d and f). If the error correction processing results in an error, the error correction processing error information is transmitted to the external device, and the processing is completed (processing f). When the error correction processing is performed normally (processing f), the two-dimensional code information is decoded (processing h), the decoding result is transmitted to an external device (processing k), and the decoding processing is completed normally. According to the above processing, for example, when the two-dimensional code reader 10 as shown in FIG. 7 is installed at the site, the installation can be performed with reference to the error information transmitted to the information processing terminal 13 connected to the two-dimensional code reader 10. For example, when a binarization error is transmitted, there is a high possibility that the luminance of the external illumination light source 11 or the light receiving lens 2 is incorrectly adjusted, and when an error correction processing error is transmitted, a printing error of the two-dimensional code 1 itself is caused. Can be estimated to be high, so that the work efficiency can be improved as compared with the installation work using only the image monitor 12.
[0018]
FIG. 3 is a flowchart showing an embodiment of the second, third, and fourth two-dimensional code readers of the present invention. After decoding the two-dimensional code information (processing step c), the microprocessor 6 calculates the brightness difference (contrast value) between the bright and dark parts at a predetermined position with respect to the light and dark patterns (cells) constituting the two-dimensional code. Calculate (processing). In the present embodiment, as shown in FIG. 2, the average of the bright part pattern (cell) and the dark part pattern (cell) at the position of the center (scanning lines a and b) in the X and Y directions of the two-dimensional code. The difference between the values was determined and used as the contrast value. In the present embodiment, two scanning lines a and b are used. However, the number of scanning lines is increased to increase the contrast value or the contrast value in the central area of the two-dimensional code (near the intersection of the scanning lines a and b). It is also possible to calculate. Further, the contrast value calculation result and the decoding result information are transmitted to the external device, and the decoding process is completed (processing steps S and S).
[0019]
Further, the contrast value calculation result is compared with a predetermined value (processing step). If the comparison result is smaller than the predetermined value, a warning is displayed on the external display unit 9 (processing step), and the decoding result is transmitted to the external device. Processing is completed (processing section). In the present embodiment, the red LED is lit on the external display unit 9.
[0020]
Further, in the embodiment of the present invention, the warning information is transmitted to the external device together with the decryption result information, and the processing is completed (processing steps S and S). In the present embodiment, no warning display is performed on the external display unit 9, but it is also possible to transmit warning information and also to turn on the warning display 9.
[0021]
FIG. 4 is a flowchart showing one embodiment of the fifth, sixth, and seventh two-dimensional code readers of the present invention. After decoding the two-dimensional code information (processing step h), the microprocessor 6 performs error correction processing information calculation processing (processing step). In a main two-dimensional code whose international standardization is being advanced, an error correction function using a Reed-Solomon code is used. The Reed-Solomon code is arranged in the data display area of the two-dimensional code for data recovery, and by performing numerical processing in the decoding process, data lost due to dirt or the like can be recovered. An error locator polynomial is generated in the calculation process of the data restoration. By detecting the degree of the polynomial, it is possible to detect the number of errors in the code undergoing the decoding process. In the present embodiment, the ratio of the number of errors to the decryption information is calculated and used as error correction information. In the fifth two-dimensional code reader according to the present invention, the error correction information is transmitted to the external device together with the decoding result, and the decoding process is completed (process T, G).
[0022]
Further, in this embodiment, the error correction information calculation result is compared with a predetermined value (processing H), and if the comparison result is larger than the predetermined value, a warning is displayed on the external display unit 9 (processing H), and the decoding result is obtained. Is transmitted to the external device to complete the process (process G). In this embodiment, the red LED is turned on on the external display unit 9.
[0023]
Further, in the present embodiment, the warning information is transmitted to the external device together with the decryption result information, and the process is completed (processes g and n). In the present embodiment, the warning display is not performed on the external display unit 9, but the warning information can be transmitted and the warning display 9 can be turned on.
[0024]
As described in the above embodiment, the contrast value or the error correction information is transmitted to an external device, or is compared with a predetermined value, and when the comparison result exceeds a predetermined range, warning information is externally displayed. Alternatively, by transmitting, it is possible to detect a change in code printing quality and a change in luminance of the illumination light source, and for example, it is possible to prevent a decrease in the reading rate during operation of the production line in advance.
[0025]
【The invention's effect】
The two-dimensional code reader of the present invention can be easily installed on a production site or the like, and also displays a warning beforehand for a change in printing quality during operation or a decrease in the luminance of an illumination light source before the reading rate is reduced. In addition, measures can be taken.
[Brief description of the drawings]
FIG. 1 is a diagram showing a processing flow of one embodiment of a two-dimensional code reader of the present invention; FIG. 2 is a diagram for explaining a contrast value calculation process according to one embodiment of a two-dimensional code reader of the present invention; FIG. 3 is a diagram showing a processing flow of one embodiment of the two-dimensional code reader of the present invention. FIG. 4 is a diagram showing a processing flow of one embodiment of the two-dimensional code reader of the present invention. FIG. 6 is a diagram showing an example of a two-dimensional code reader. FIG. 6 is a diagram showing a configuration example of a two-dimensional code reader of the present invention. FIG. 7 is a diagram showing an example of installation of a two-dimensional code reader of the present invention at a production site. ]
DESCRIPTION OF SYMBOLS 1 Two-dimensional code 2 Light-receiving lens 3 Image sensor 4 Circuit part 5 Image memory 6 Microprocessor 7 Communication part 8 Monitor interface 9 External display part 10 Two-dimensional code reader 11 Illumination light source 12 Image monitor 13 Information processing terminal

Claims (7)

A light-receiving lens that forms an image of a two-dimensional code on an image sensor; an image sensor that converts the image of the two-dimensional code into an electric signal; and an A / D converter that converts an output signal of the image sensor into a digital signal An image memory that stores the output signal of the A / D converter, a decoding unit that processes information in the image memory and decodes the information of the two-dimensional code, and transmits decoding information of the decoding unit to an external device. A two-dimensional code reader configured to include: a communication unit configured to perform decoding error information from the communication unit to an external device when the decoding unit cannot decode the information of the two-dimensional code and a decoding error occurs. A light-receiving lens that forms an image of a two-dimensional code on an image sensor, an image sensor that converts the image of the two-dimensional code into an electric signal, and an A / D converter that converts an output signal of the image sensor into a digital signal An image memory for storing the output signal of the A / D converter, a decoder for processing the information in the image memory to decode the information of the two-dimensional code, and a communication unit for transmitting the decoded information of the decoder to an external device. When the decoder decodes the information of the two-dimensional code, the decoder contrasts the contrast value of the pattern of the bright part and the dark part at a predetermined position constituting the two-dimensional code together with the decoding information of the two-dimensional code from the communication unit. A two-dimensional code reader that transmits to devices. 3. The two-dimensional code reader according to claim 2, further comprising a display function of comparing a contrast value with a preset value, and displaying a result of the comparison when the comparison result is smaller than a predetermined value to an external device. 3. The two-dimensional code reader according to claim 2, further comprising a function of comparing a contrast value with a preset value, and transmitting a warning information from the communication unit to an external device when the comparison result is smaller than a predetermined value. 4. A light-receiving lens that forms an image of a two-dimensional code on an image sensor, an image sensor that converts the image of the two-dimensional code into an electric signal, and an A / D converter that converts an output signal of the image sensor into a digital signal An image memory that stores the circuit unit output signal, a decoder that processes information in the image memory and decodes the information of the two-dimensional code, and a communication unit that transmits decoding information of the decoder to an external device, A two-dimensional code reader which transmits error correction information calculated at the time of decoding the information of the two-dimensional code of the decoder together with the decoding information of the two-dimensional code from the communication unit to an external device. 6. The two-dimensional code reader according to claim 5, further comprising a display function of comparing the error correction information with a preset value, and displaying the result of the comparison when the comparison result is larger than a predetermined value to an external device. The two-dimensional code reader according to claim 5, further comprising a function of comparing the error correction information with a preset value, and transmitting a warning information from the communication unit to an external device when the comparison result is larger than a predetermined value. .

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