JP2009093443A - Two-dimensional code and its scanning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-dimensional code and its scanning device in which encryption is difficult to be identified by a user of the two-dimensional code, without causing an increase in equipment cost and running cost. <P>SOLUTION: In a QR code 10, a key pattern 18 in which a designated encryption key is coded is recorded on a pattern using a bright module and a dark module which are a unit module 11 used for coding the QR code by overlapping at least on either a data pattern 15 or an error correction pattern 16. Thus the key pattern 18 is composed of the bright module and the dark module which are the unit module 11 constituting the data pattern 15 for the QR code 10, and a different shape cell is not needed. Accordingly, since a label printer can print the data pattern 15 constituting the QR code 10, its error correction pattern 16, and also the key pattern 18 such as this, either necessity to especially enhance printing precision or a unique printing characteristic is not needed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a two-dimensional code and a reading device thereof.

  Data code word in which part or all of the encrypted data is encoded with the code specification of the two-dimensional code, and error correction data in which the error correction data that can detect and correct the error of this data code word is encoded with the code specification As a two-dimensional code in which a code word is recorded, for example, there is a “two-dimensional code” disclosed in Patent Document 1 below.

According to this, in order to give confidentiality to the data recorded as a two-dimensional code, the character string information that can specify the encryption key is made to correspond to the shape of the dark unit cell constituting the two-dimensional code. To do. For example, for a unit cell composed of 10 dots × 10 dots, 10 types of shapes are formed by a missing region of 2 dots × 2 dots and the number and position of the missing regions, and 10 corresponding to each shape. By associating with types of characters (for example, numbers 0, 1 to 9), a character string that can specify the encryption key is configured.
JP 2006-4378 A

  However, according to the technique disclosed in Patent Document 1, although an encryption key can be specified from a combination of character strings corresponding to the irregular shape of the unit cell, the irregularly shaped cell having such a missing area. When printing on a display medium such as paper or film, it is necessary to increase the printing accuracy, and in terms of printing characteristics such as ink bleed, ink bleed or ink on the ink and paper used for printing. What is required is high.

  For this reason, since it is difficult to cope with a highly versatile label printer or label paper, there is a problem that an increase in equipment cost and running cost is caused.

  In addition, for a user who can recognize that the two-dimensional code is encrypted because the two-dimensional code includes such a strangely shaped cell having an uncomfortable appearance, Security problems may also arise because it may give inadvertent motivation to attempt to decrypt the code.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to cause an increase in equipment cost and running cost and to be encrypted by a user of the two-dimensional code. It is an object of the present invention to provide a two-dimensional code and a reading device thereof that are difficult to recognize.

  In order to achieve the above object, in the two-dimensional code of claim 1 according to the claims, a data code word obtained by encoding a part or all of the encrypted data with the code specification of the two-dimensional code, A two-dimensional code that records error correction code words in which error correction data that can detect and correct errors in a data code word is encoded according to the code specifications, and is a unit cell used for the encoding A technical feature is that a key code pattern obtained by encoding key data used for decrypting the data in a pattern using a light / dark module is recorded in duplicate in at least one of the data code word and the error correction code word. And Here, the “module” is a minimum component constituting the two-dimensional code, and the “bright / dark module” is a light color (for example, a color with high brightness such as white) and a dark color (for example, black). This is a concept representing both a light color module (light module) and a dark color module (dark module) in the case of two types of low-lightness colors.

  In the two-dimensional code of claim 2 according to the claims, in the two-dimensional code of claim 1, the key code pattern is arranged avoiding a function pattern required to decode the data code word. Is a technical feature.

  The two-dimensional code reader according to claim 3, which decodes the two-dimensional code according to claim 1 and 2 and decrypts the encrypted data using the key data. A dimension code reader, wherein error detection means for detecting an error in the data code word, and the position where the error detected by the error detection means is the range information in which the key code pattern is recorded. If it is within a predetermined range specified based on what it has in advance, the key code pattern acquisition means for acquiring the key code pattern recorded in the predetermined range, and the key code pattern acquisition means Key data decoding means for decoding the key code pattern to generate the key data, and decoded by the key data decoding means And technical features in that it comprises a decryption means for decrypting the encrypted data using the key data.

  5. The two-dimensional code reader according to claim 4, wherein the key code pattern acquisition means is configured such that the position where the error occurs is within the predetermined range. The key feature is that the key code pattern recorded in the predetermined range is acquired only when there are a plurality of the key code patterns in the predetermined range.

  According to the first aspect of the present invention, a key code pattern obtained by encoding key data used for data decryption into a pattern using a light / dark module, which is a unit cell used for encoding, is at least one of a data code word and an error correction code word. Are duplicated. As a result, the key code pattern is configured using the light / dark module, which is a unit cell that constitutes the data code word of the two-dimensional code, and therefore does not require an irregularly shaped cell as disclosed in Patent Document 1 described above. . For this reason, such a key code pattern can also be printed by a printing technique necessary for recording the data code word constituting the two-dimensional code and its error correction code word, so that it is particularly necessary to increase printing accuracy or special printing. Does not require characteristics. Further, since such a key code pattern is recorded in duplicate in at least one of the data code word and the error correction code word, it is difficult to visually distinguish them from these code words. Accordingly, it is possible to make it difficult for the user of the two-dimensional code to recognize that it is encrypted without causing an increase in equipment cost or running cost.

  In the invention of claim 2, the key code pattern is arranged avoiding the function pattern required to decode the data code word. Thereby, in the reading device that reads the two-dimensional code, the reading device can read the key data based on the key code pattern without hindering the decoding process.

  According to the third aspect of the present invention, an error in the data code word is detected by the detecting means, and the position where the error detected by the error detecting means is preliminarily stored in the range information in which the key code pattern is recorded. If the key code pattern exists within the specified range, the key code pattern recorded in the predetermined range is acquired by the key code pattern acquisition means. The key code pattern acquired by the key code pattern acquisition means is decoded by the key data decoding means to generate key data, and the encrypted data is decrypted using the key data decoded by the key data decoding means. Decrypt by means. As a result, when a normal two-dimensional code in which a key code pattern is not recorded in duplicate in at least one of the data code word and the error correction code word is read, an error in the data code word is accidentally within such a predetermined range. Except when it occurs, it is possible to prevent a code pattern that is not a key code pattern from being erroneously read as a key code pattern. Therefore, it is possible to decode these data by distinguishing between a two-dimensional code including such a key code pattern and a normal two-dimensional code not including the key code pattern.

  In the invention of claim 4, since the key code pattern acquisition means acquires the key code pattern recorded in the predetermined range only when there are a plurality of positions where the error has occurred in the predetermined range, Even if a data code word error occurs accidentally within the predetermined range, the key code pattern recorded in the predetermined range is not changed unless such accident occurs in more than one place within the same predetermined range. Never get. Therefore, it is possible to decode these data after more accurately distinguishing between a two-dimensional code including such a key code pattern and a normal two-dimensional code not including the key code pattern.

  Hereinafter, embodiments of the two-dimensional code and the reading device of the present invention will be described with reference to the drawings. First, an embodiment according to the two-dimensional code of the present invention will be described with reference to FIGS. In this embodiment, the QR code is described as an example of the two-dimensional code. However, the function pattern required for decoding the data encoded in the two-dimensional code, the data and the information associated therewith are encoded. The present invention can be applied to, for example, a data matrix code, a maxi code, a veri code, a carla code, a CP code, etc., as long as the data pattern is a two-dimensional code recorded therein.

  As shown in FIG. 1, the QR code 10 according to the present embodiment is configured substantially in accordance with the basic specifications of the QR code (Japanese Industrial Standard; JIS X 0510: 2004, hereinafter simply referred to as “JIS standard”). The function pattern includes a finder pattern 12, an alignment pattern 13, a timing pattern 14, and the like, a data pattern 15, an error correction pattern 16, and a key pattern 18. The QR code 10 shown in FIG. 1 corresponds to a 7-type in which the unit modules 11 are arranged in a matrix of 45 rows and 45 columns, and an error correction level H is set.

  The finder pattern 12 is also referred to as a cutout symbol or an alignment pattern, and is an aggregate of a plurality of unit modules 11 arranged in a square located at three corners of the QR code 10, and the position and size of the QR code. Now, it is structured and recorded so that the inclination can be detected. Specifically, for example, a 3 × 3 dark module in which black unit modules 11 are arranged in a matrix of 3 rows and 3 columns, and a white unit module 11 are arranged in a matrix of 5 rows and 5 columns so as to surround it. It is composed of a 5 × 5 light module and a 7 × 7 dark module in which black unit modules 11 are arranged in a matrix of 7 rows and 7 columns so as to surround these. For this reason, when light / dark information is scanned so as to traverse or traverse the finder pattern 12, the continuous ratio of the same color modules becomes 1: 1: 3: 1: 1 in the order of dark, bright, dark, bright, dark. Utilizing this, the image range is the finder pattern 12 and the center position of the finder pattern 12 is detected. That is, the finder pattern 12 enables detection of the QR code 10 in all directions of 360 degrees.

  The alignment pattern 13 is also an aggregate of a plurality of unit modules 11 arranged in a square, and is recorded so as to be able to correct the distortion of the QR code 10, and is within a square range defined by the three finder patterns 12. It is located at a predetermined location. Specifically, for example, 1 unit module 11 minutes of independent black 1 × 1 dark module, 8 white 3 × 3 light modules surrounding the 1 × 1 dark module, and the square 3 It consists of 16 black 5x5 dark modules surrounding the periphery of the x3 light module. This alignment pattern 13 facilitates detection of the center coordinates.

  The timing pattern 14 is a repeating pattern of the unit module 11 in which the white and black unit modules 11 appear repeatedly, which enables timing extraction for obtaining the center coordinates of each unit module 11. The white 1 × 1 bright module and the black The 1 × 1 dark modules are alternately arranged in a straight line. For example, when the QR code 10 is distorted or an error occurs in the pitch of the unit module 11, it is used to correct the center coordinates of the unit module 11. The timing pattern 14 is recorded in each of the vertical direction and the horizontal direction of the QR code 10 so as to pass through the center of the alignment pattern 13.

  The data pattern 15 is configured by arranging the unit modules 11 in 4 rows and 2 columns, for example, and can express data of 8 bits from bit 0 to bit 7. In FIG. 1, an example including 66 words of data code words D1 to D66 is shown. As will be described later, a part or all of the data pattern 15 is obtained by converting data encrypted by a predetermined encryption key (key data) (hereinafter referred to as “encrypted data”) into a QR code data pattern. . Therefore, even if the QR code 10 is read by a two-dimensional code reader of a normal specification, the encrypted portion of data is decoded as an unknown character string.

  Similarly to the data pattern 15, the error correction pattern 16, for example, is configured by arranging the unit modules 11 in 4 rows and 2 columns, and can express 8-bit data. The data pattern (data code word) For example, error correction data necessary for executing a Reed-Solomon error correction algorithm is configured for 15. FIG. 1 illustrates an example including 130 words of error correction code words E1 to E130.

  The data pattern 15 and the error correction pattern 16 are recorded in a data pattern area other than the function pattern area in which the finder pattern 12, the alignment pattern 13, and the timing pattern 14 are arranged. In addition, a quiet zone having a width of 4 modules (4 unit modules 11) is secured around the QR code 10 because the reader of the QR code 10 needs to recognize the outline and presence of the finder pattern 12 described above. ing.

  The QR code conforming to the JIS standard is configured in this way, for example. However, the QR code 10 according to the present embodiment overlaps, for example, by overwriting the error correction pattern 16 as shown in FIG. Thus, the key patterns 18 are arranged so as to overlap each other. In the example shown in FIG. 1, the key pattern 18 is arranged overlapping the E45, E68, and E118 portions of the error correction pattern 16.

  The key pattern 18 is used for decrypting the encrypted data of the encrypted portion of the data pattern 15. For example, the key pattern 18 is arranged so as to overwrite the error correction pattern 16 or the data pattern 15. Yes. By arranging the key pattern 18 so as to overlap the error correction pattern 16 or the like in this way, the data of a part of the overlapped error correction pattern 16 is broken. It is corrected by the error correction function it has. Therefore, the maximum range in which the key pattern 18 is arranged is determined by the error correction level of the QR code.

  That is, according to the JIS standard, when the error correction level of the QR code 10 is set to “L”, the restoration capability by Reed-Solomon error correction is 7%, so the data pattern 15 and the error correction pattern 16 It is possible to arrange the key pattern 18 up to a range of 7% with respect to the whole. Further, when the error correction level is set to “M”, the restoration capability is 15%, so that the key pattern 18 can be arranged in a range of 15% of the whole, and the error correction level is “Q”. ”Is set, the key pattern 18 can be arranged in a range of 25% of the whole because the restoration ability is 25%. Further, as in the example of the present embodiment, when the error correction level is set to “H”, the restoration ability is 30%, so the entire 30% range, that is, 58 words (= (66 words). The key pattern 18 can be overlapped with the area up to the area occupied by +130 words) × 0.3).

  As an arrangement example of the key pattern 18, for example, as shown in FIG. 2, in the error correction pattern area or the data pattern area, the key pattern 18α (broken line) arranged so as to straddle the data pattern 15 or the error correction pattern 16 in the horizontal direction. a range of α), a key pattern 18β (range of broken line β) arranged so as to straddle the data pattern 15 or the error correction pattern 16 or a data pattern 15 or error correction pattern 16 so as to straddle the four directions. There is a key pattern 18γ (range of broken line γ). The “horizontal direction” here means the column direction (short direction) with respect to the unit module 11 of 4 rows and 2 columns constituting the data pattern 15 and the error correction pattern 16, and “vertical direction” means , Meaning the row direction (longitudinal direction) for the unit module 11 of 4 rows and 2 columns.

  Although not shown, a horizontal key pattern 18α and a vertical key pattern 18β are mixed, a horizontal key pattern 18α and a four-way key pattern 18γ are mixed, and a vertical key. Even a combination of the pattern 18β and the vertical key pattern 18β or a combination of the horizontal key pattern 18α, the vertical key pattern 18β, and the four-direction key pattern 18γ. good.

  As in the example shown in FIG. 2, when the key pattern 18α or the like is scattered in a plurality of locations in the error correction pattern region or the data pattern region, the total area of the scattered key pattern 18α or the like is described first. The key pattern 18 must be within the maximum range (L: 7%, M: 15%, Q: 25%, H: 30%). The error correction pattern area and the data pattern area are as shown in FIG. 3, and the key pattern 18α and the like are preferentially arranged from the error correction pattern area in a range excluding the function pattern such as the finder pattern 12. Thereby, in the two-dimensional code reader 20 that reads the QR code 10 to be described later, it is possible to read the key data by the key pattern 18 into the two-dimensional code reader 20 without hindering the decoding process.

  Next, a method for generating the QR code 10 will be described with reference to FIGS. This generation method is performed by, for example, an information processing apparatus such as a personal computer (hereinafter referred to as “personal computer”). Here, the generation method is performed by a label printer that is generated by a personal computer (not shown) and connected to the personal computer. In the following description, it is assumed that a QR code is printed on the label and output.

  As shown in FIG. 4, first, a data fetching process for fetching data to be coded as a QR code is performed in step S011. This data is configured according to a data format as shown in FIG. 5, for example. Disclosure data A and disclosure data B shown in FIG. 5 are data that does not need to be encrypted, and secret data C and secret data D need to be encrypted that you do not want to disclose to third parties (you want to keep secret). It is data with. A secret identifier and a data length of the entire secret data are stored before the secret data C and the like.

  And the process which encrypts a part or all of this taken-in data by following step S013 is performed. The encryption process in step S013 is performed using the predetermined encryption key described above, and in the example of data shown in FIG. 5, the secret data C and the secret data D are to be encrypted.

  In the subsequent entire data pattern generation process in step S015, the entire data composed of the encrypted data (secret data C, D) encrypted in step S013 and the unencrypted non-encrypted data (disclosure data A, B) is obtained. Based on the specifications of the JIS standard, a process for generating a QR code data pattern 15 and an error correction pattern 16, that is, a patterning process is performed. The QR code data pattern 15 and error correction pattern 16 are not printed and output, but are stored in the memory space of the personal computer.

  In step S017, key data pattern generation processing is performed. In this process, the key data that is the above-described predetermined encryption key is generated as a QR code pattern, and the pattern generated thereby is the above-described key pattern 18, 18α, 18β, 18γ (hereinafter referred to as “key pattern 18 etc.”). ").

  In step S019, pattern data synthesis processing is performed. That is, a process of overwriting the data pattern 15 and error correction pattern 16 generated in step S015 with the key pattern 18 and the like generated in step S017 is performed. This overwriting is performed in the memory space, and as described above, the key pattern 18 and the like are overlaid on the error correction pattern 16 in preference to the error correction pattern area, that is, overwritten.

  The pattern data synthesized in this way is output to the label printer in step S021, whereby the QR code 10 according to the present embodiment is printed on the label. Here, the description has been made assuming that the output device is a label printer. However, the present invention is not limited to this, and in addition to a printer capable of printing on a print medium such as paper or film, the output device may be a display medium such as a liquid crystal display. A configuration for outputting the QR code 10 may be adopted.

  As described above, according to the QR code 10 according to the present embodiment, a predetermined encryption key (key) is used in a pattern using a light module and a dark module (light / dark module) which are unit modules 11 used for coding the QR code. A key pattern 18 or the like obtained by encoding (data) is recorded in duplicate in at least one of the data pattern 15 (data code word) and the error correction pattern 16 (error correction code word).

  As a result, the key pattern 18 and the like are configured using the light / dark module, which is the unit module 11 that configures the data pattern 15 of the QR code 10, and thus requires an irregularly shaped cell as disclosed in Patent Document 1 described above. And not. For this reason, such a key pattern 18 can be printed (recorded) by a label printer or the like that can print the data pattern 15 and the error correction pattern 16 constituting the QR code 10. Does not require printing characteristics.

  In addition, such a key pattern 18 and the like is printed (recorded) casually and overlaps at least one of the data pattern 15 and the error correction pattern 16, so that it is difficult to visually distinguish them from these patterns. Become. As a result, for example, when managing products such as lucky bags that have different appearances but the appearance of the product is uniform and cannot be distinguished by appearance and cannot be opened, the product information of the contents is encrypted data By attaching a label or the like on which the QR code 10 is printed, the encrypted data of the QR code 10 can be read by the two-dimensional code reader 20 described later or the QR code reading function can be provided by a shopper's personal mobile phone. You can configure an application example that cannot read the contents of the lucky bag.

  As described above, in the QR code 10 according to the present embodiment, it is possible to make it difficult for the user of the QR code 10 to recognize that it is encrypted without causing an increase in equipment cost or running cost.

  Next, the configuration of the two-dimensional code (QR code) reader 20 according to the two-dimensional code reader of the present invention will be described with reference to FIGS. FIG. 6 is a block diagram illustrating a hardware configuration example of the two-dimensional code reader 20 according to the present embodiment.

  As shown in FIG. 6, the two-dimensional code reader 20 mainly includes an optical system such as an illumination light source 21, a light receiving sensor 23, and an imaging lens 22, a memory 35, a control circuit 40, an operation switch 42, and a liquid crystal display 46. And a power supply system such as a power switch 41 and a battery 49. These are mounted on a printed wiring board (not shown) or housed in a housing (not shown), and are configured in the same manner as a QR code reader (reading device) of general specifications in hardware.

  The optical system includes an illumination light source 21, a light receiving sensor 23, an imaging lens 22, and the like. The illumination light source 21 functions as an illumination light source capable of emitting illumination light Lf, and includes, for example, a red LED and a diffusion lens, a condensing lens, and the like provided on the emission side of the LED. In the present embodiment, illumination light sources 21 are provided on both sides of the light receiving sensor 23, and the illumination light Lf can be irradiated toward the label P through a reading port of a case (not shown). The QR code 10 described above is printed on the label P.

  The light receiving sensor 23 is configured to be able to receive the reflected light Lr irradiated and reflected on the label P or the QR code 10, and for example, a light receiving element which is a solid-state imaging element such as a C-MOS or CCD is two-dimensionally arranged. The arranged area sensor corresponds to this. The light receiving sensor 23 is mounted on a printed wiring board (not shown) so that incident light incident through the imaging lens 22 can be received by the light receiving surface 23a.

  The imaging lens 22 functions as an imaging optical system capable of condensing incident light incident through the reading port from the outside and forming an image on the light receiving surface 23a of the light receiving sensor 23. And a plurality of condensing lenses housed in the lens barrel.

  Next, a configuration outline of the microcomputer system will be described. The microcomputer system includes an amplification circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control circuit 40, an operation switch 42, an LED 43, a buzzer 44, a liquid crystal display 46, and a communication interface 48. Etc. As the name suggests, this microcomputer system is composed of a control circuit 40 and a memory 35 that can function as a microcomputer.

  An image signal output from the light receiving sensor 23 of the optical system is amplified by a predetermined gain by being input to the amplification circuit 31 and then converted from an analog signal to a digital signal when input to the A / D conversion circuit 33. Is done. When the digitized image signal, that is, image data is input to the memory 35, it is stored in the image data storage area. The synchronization signal generation circuit 38 is configured to generate a synchronization signal for the light receiving sensor 23 and the address generation circuit 36. The address generation circuit 36 is based on the synchronization signal supplied from the synchronization signal generation circuit 38. Thus, the storage address of the image data stored in the memory 35 can be generated.

  The memory 35 is a semiconductor memory device, and corresponds to, for example, a RAM (DRAM, SRAM, etc.) or a ROM (EPROM, EEPROM, etc.). In addition to the above-described image data storage area, the RAM of the memory 35 is configured so as to be able to secure a work area used by the control circuit 40 during each processing such as arithmetic operation and logical operation. In addition, the ROM stores in advance a predetermined program capable of executing a decoding process described later, a system program capable of controlling each hardware such as the illumination light source 21 and the light receiving sensor 23, and the like.

  The control circuit 40 is a microcomputer capable of controlling the entire two-dimensional code reader 20, and includes a CPU, a system bus, an input / output interface, and the like. The control circuit 40 can constitute an information processing apparatus together with the memory 35 and has an information processing function. The control circuit 40 is configured to be connectable to various input / output devices via a built-in input / output interface. In the case of this embodiment, the power switch 41, operation switch 42, LED 43, buzzer 44, liquid crystal. A display 46, a communication interface 48, and the like are connected.

  Thereby, for example, monitoring and management of the power switch 41 and the operation switch 42, turning on / off the LED 43 functioning as an indicator, turning on / off the buzzer 44 capable of generating a beep sound and an alarm sound, and further reading the QR code This makes it possible to control the screen of the liquid crystal display 46 capable of displaying the code content by the communication, the communication control of the communication interface 48 enabling serial communication with an external device, and the like. The external devices connected to the communication interface 48 include a host computer HST corresponding to the host system of the two-dimensional code reader 20 and the like.

  The power supply system includes a power switch 41, a battery 49, and the like. When the power switch 41 managed by the control circuit 40 is turned on and off, the conduction of the drive voltage supplied from the battery 49 to each of the above-described devices and circuits is performed. Or shut off is controlled. The battery 49 is a secondary battery capable of generating a predetermined DC voltage, and corresponds to, for example, a lithium ion battery. Further, the battery 49 may be configured to receive power supply from an external device such as the host computer HST connected via the communication interface 48 without using the battery 49. In this case, the battery 49 is unnecessary.

  By configuring the two-dimensional code reader 20 in this manner, for example, when the power switch 41 is turned on and a predetermined self-diagnosis process or the like is normally completed and the QR code 10 can be read, the illumination light Lf can be read. An input of an operation switch 42 (for example, a trigger switch) that instructs light emission is received. Accordingly, when the user pulls the trigger switch to turn it on, the control circuit 40 outputs a light emission signal to the illumination light source 21 based on the synchronization signal, and the illumination light source 21 that has received the light emission signal turns on the LED. Light is emitted to irradiate illumination light Lf.

  Then, the illumination light Lf applied to the QR code 10 is reflected, and the reflected light Lr enters the imaging lens 27 through the reading port. Therefore, the image of the QR code 10 is formed on the light receiving surface 23a of the light receiving sensor 23. Is imaged. Thereby, since the image of the QR code 10 exposes the light receiving sensor 23, the image data of the QR code 10 subjected to the image processing by the microcomputer system described above will be described below through the image data storage area of the memory 35. Passed to the decoding process.

  Here, the decoding process will be described with reference to FIGS. FIG. 7 is a flowchart showing the flow of the decoding process. FIG. 8 is a flowchart showing the flow of the error position detection process shown in FIG. FIG. 9 is an explanatory diagram showing the concept of the error position match determination process shown in FIG.

  As shown in FIG. 7, the decoding process is started by the control circuit 40 and the memory 35 that are activated when the two-dimensional code reader 20 is turned on. First, the image data capturing process is performed in step S101. This process reads image data stored in the image data storage area of the memory 35.

  In step S103, the entire decoding process is performed. In this process, the data pattern 15 is decoded based on the finder pattern 12, the alignment pattern 13, the timing pattern 14, and the error correction pattern 16 constituting the QR code 10 according to the JIS standard.

  In the QR code 10, as described above, a part of the data pattern 15 (the secret data C and D) is encrypted. Therefore, even if the disclosed data A and B can be decoded as a meaningful character string, The encrypted data is decoded as a character string with an unknown meaning in this step S103. Further, since the key pattern 18 and the like are arranged and printed (recorded) on the error correction pattern 16 or the data pattern 15, a “data error” always occurs in this process. For this reason, the position where this data error occurs is detected in the next step S105. The details of step S105 are shown in FIG. 8, and will now be described with reference to FIG.

  As shown in FIG. 8, in the error position detection process, first, an error detection process is performed in step S201. This process is performed on the data pattern 15 and the error correction pattern 16 in accordance with a Reed-Solomon error detection algorithm according to the JIS standard. For example, in the example shown in FIG. 1, since the key pattern 18 is arranged redundantly in the portions of E45, E68, and E118 in the error correction pattern 16, an error is detected for the data pattern 15 corresponding thereto. The

  When an error is detected in step S201 (S203; Yes), in step S205, the data pattern 15 having the data error is corrected by the Reed-Solomon error correction algorithm, and then the error in step S207 is detected. The position (corresponding to the code arrangement of the QR code) where an error is detected by the position storage process is stored. On the other hand, if no error is detected from step S201 (S203; No), the process proceeds to step S209.

  In step S209, it is determined whether or not errors have been detected for all data patterns 15. If all data has not been completed (S209; No), the process returns to step S201 to perform error detection processing for the next data pattern 15. Done.

  If it is determined in step S209 that all data has been completed (S209; Yes), this error position detection process is terminated, and the process proceeds to step S107 in FIG.

  Returning to FIG. 7, an error location analysis process is performed in step S107. In this process, each error position stored in the error position storage process (S207) of the error position detection process described above is analyzed, for example, as shown in FIG. FIG. 9A schematically shows data patterns 15 that can be decoded and read in a row, and FIG. 9B schematically shows a predetermined error occurrence position. 9 (C) to 9 (G) schematically show error positions actually generated.

  In step S107, for example, as shown in FIG. 9B, an error is detected in advance at positions B3, B4, and B7 in the data pattern 15 by overlapping the key pattern 18 and the like. If scheduled, these positions are compared with the error detected positions (corresponding to the code arrangement of the QR code). Note that the position (range information) where errors are scheduled to be detected in advance is stored in the memory 35 when the two-dimensional code reader 20 is adjusted at the factory or at the time of shipment.

  As a result, for example, as shown in FIG. 9C, positions (B3, B4, B7) where errors are scheduled to be detected in advance and positions (C3, C4, C7) where errors are detected are obtained. If they match completely, it is assumed that C3, C4, and C7 are all due to the arrangement of the key pattern 18 and the like. Therefore, in the subsequent step S109, errors concentrate on a specific range. (S109; Yes), and in step S111, it is determined that the key pattern 18 and the like coincide with each other (S111; Yes), and the process proceeds to step S113.

  On the other hand, for example, as shown in FIG. 9 (D), a position where an error is detected at a position that is not related to a position (B3, B4, B7) that is scheduled to be detected in advance. When (D2, D6) varies, it is assumed that these D2, D6 are not due to the arrangement of the key pattern 18 or the like, but are data errors due to completely different factors. In subsequent step S109, it is determined that the errors are not concentrated in the specific range (S109; No), and the process proceeds to step S117.

  Further, as shown in FIGS. 9E and 9F, positions (B3, B4, B7) where errors are scheduled to be detected in advance and positions (E3, E4, E5) where errors are detected. , E7) and (F3, F4, E7, F8) are not completely coincident with each other but include the planned positions (B3, B4, B7), these E3, E4, E5, E7, Since F3, F4, E7, and F8 are all assumed to be due to the arrangement of the key pattern 18 and the like, it is determined in the subsequent step S109 that errors are concentrated in a specific range (S109; In step S111, it is determined that the key pattern 18 or the like is matched (S111; Yes), and the process proceeds to step S117.

  Further, for example, as shown in FIG. 9 (G), a position (B3, B4, B7) where an error is scheduled to be detected in advance and a position (G3, G4, G5) where the error is detected are one. In the case of partial match, as in the case of FIG. 9D, it is presumed that it is not due to the arrangement of the key pattern 18 and the like, so in the subsequent step S109, errors are concentrated on a specific range. Even if it is determined (S109; Yes), it is determined in step S111 that it does not coincide with the position of the key pattern 18 or the like (S111; No), and the process proceeds to step S117.

  In step S113, a process for obtaining the key pattern 18 and the like is performed, and the key data is decoded from the image data obtained thereby in the next step S115.

  In the following step S117, the key data decoded in step S115, that is, the encrypted data is decoded using a predetermined encryption key, so that the encrypted data decoded as an unknown character string in step S103 is stored as the secret data C, D Can be decoded as

  In step S119, the data decoded in step S103 (disclosure data A and B) and the data decoded in step S117 (secret data C and D) are output to the liquid crystal display 46 or via the communication interface 48. Data output processing to be output to the host computer HST is performed.

  As described above, according to the two-dimensional code reader 20 according to the present embodiment, an error in the data pattern 15 is detected by the control circuit 40 or the memory 35 (hereinafter referred to as “control circuit 40 or the like”) (S105, 203). A predetermined range in which the position where the detected error has occurred is specified based on the position (range information) that is expected to be detected in advance because the key pattern 18 or the like is recorded. (S111; Yes), the key pattern 18 or the like recorded in the predetermined range is acquired by the control circuit 40 or the like (S113). The acquired key pattern 18 and the like are decoded by the control circuit 40 and the like to generate a predetermined encryption key (key data) (S115), and the data encrypted using the predetermined encryption key is transmitted to the control circuit 40 and the like. (S117).

  As a result, when a normal QR code in which the key pattern 18 or the like is not recorded in duplicate in at least one of the data pattern 15 and the error correction pattern 16 is read, an error in the data pattern 15 happens to occur within such a predetermined range. Except when it occurs, it is possible to prevent a code pattern other than the key pattern 18 or the like from being erroneously read as the key pattern 18 or the like. Therefore, these data can be decoded by distinguishing the QR code 10 including the key pattern 18 and the like from the normal QR code not included.

  It should be noted that the steps after step S109 are performed only when there are a plurality of positions where errors occur as shown in FIGS. 9C to 9G within a predetermined range where error detection is planned in advance. You may comprise so that the process of this may be performed. As a result, for example, even if an error in the data pattern 15 occurs accidentally within the predetermined range, the key recorded within the predetermined range unless such an accident occurs at a plurality of locations within the same predetermined range. The pattern 18 or the like is not acquired. Therefore, it is possible to decode these data after more accurately discriminating between the QR code 10 including the key pattern 18 and the like and the normal QR code not including the key pattern 18 and the like.

It is explanatory drawing which shows the structural example of QR Code which concerns on embodiment of this invention. It is explanatory drawing which shows the other structural example of QR Code which concerns on embodiment of this invention. It is explanatory drawing which shows the general structure of QR Code. It is a flowchart which shows the production | generation method of QR Code which concerns on this embodiment. FIG. 5 is an explanatory diagram illustrating a format example of data processed by the QR code generation method illustrated in FIG. 4. It is a block diagram which shows the structural example of the two-dimensional code reader which concerns on embodiment of this invention. It is a flowchart which shows the flow of the decoding process by the two-dimensional code reader which concerns on this embodiment. It is a flowchart which shows the flow of the error position detection process shown in FIG. It is explanatory drawing which shows the concept of the error position matching determination process shown in FIG.

Explanation of symbols

10, 10 '... QR code (two-dimensional code)
11 ... Unit module (unit cell)
12 ... Finder pattern (function pattern)
13 ... Alignment pattern (functional pattern)
14 ... Timing pattern (function pattern)
15 ... Data pattern (data code word)
16 ... error correction pattern (error correction code word)
18, 18α, 18β, 18γ ... key pattern (key code pattern)
20 ... Two-dimensional code reader (two-dimensional code reader)
35 ... Memory (error detection means, key code pattern acquisition means, key data decoding means, decryption means)
36 ... Address generation circuit 38 ... Synchronization signal generation circuit 40 ... Control circuit (error detection means, key code pattern acquisition means, key data decode means, decryption means)
46 ... Liquid crystal display 48 ... Communication interface S201 (error detection means), S113 (key code pattern acquisition means), S115 (key data decoding means), S117 (decryption means)

Claims (4)

A data code word obtained by coding a part or all of the encrypted data with the code specification of the two-dimensional code, and an error obtained by coding the error correction data that can detect and correct the error of the data code word with the code specification. A two-dimensional code recording correction code words,
A key code pattern obtained by encoding key data used for decrypting the data into a pattern using a light / dark module which is a unit cell used for the coding overlaps at least one of the data code word and the error correction code word. Two-dimensional code characterized by being recorded.   2. The two-dimensional code according to claim 1, wherein the key code pattern is arranged so as to avoid a functional pattern required to decode the data code word. A two-dimensional code reader for decoding the two-dimensional code according to claim 1 or 2 and for decrypting the encrypted data using the key data,
Error detection means for detecting an error in the data code word;
If the position where the error detected by the error detecting means is within a predetermined range specified based on the range information in which the key code pattern is recorded in advance, the position is recorded in the predetermined range. Key code pattern acquisition means for acquiring the key code pattern being performed;
Key data decoding means for decoding the key code pattern acquired by the key code pattern acquiring means to generate the key data;
Decryption means for decrypting the encrypted data using the key data decoded by the key data decoding means;
A two-dimensional code reader comprising:   The key code pattern acquisition means acquires the key code pattern recorded in the predetermined range only when there are a plurality of positions where the error has occurred in the predetermined range. Item 2. A two-dimensional code reader according to item 3.

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