Information code and code reading method

Abstract

This information code (CQ2) is synthesized from a public code (Cd1) and a confidential code (Cd2) which record information by using a two-dimensional array of a plurality of cells (Ce), and in addition to a white cell (Cew) and a black cell (Ceb), also contains a light color cell (Cc1) and a dark color cell (Cc2). The light color cell (Cc1) is determined to be the same as the white cell (Cew) when retrieving the public code (Cd1), and is determined to be a black cell (Ceb) when retrieving the confidential code (Cd2). The dark color cell (Cc2) is determined to be the same as the black cell (Ceb) when retrieving the public code (Cd1), and is determined to be a white cell (Cew) when retrieving the confidential code (Cd2). The confidential code (Cd2) is enlarged relative to the public code (Cd1), and one cell (Ce) of the confidential code (Cd2) is synthesized across a plurality of cells (Ce) of the public code (Cd1).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2022-87899 filed in Japan on May 30, 2022, and the contents of the original application are incorporated by reference in their entirety. [Technical Field]

[0002] The disclosure of this specification relates to a technology for an information code for recording information. [Background technology]

[0003] Patent Document 1 describes an information code that is created by combining a basic QR code (registered trademark) with another QR code. This information code includes light gray cells and dark gray cells in addition to black and white cells, and the two-dimensional arrangement of these cells makes it possible to read out the information recorded in each of the multiple QR codes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-196762 Summary of the Invention

[0005] Gray cells, which are a neutral color, are harder to distinguish than black and white cells. Therefore, when the individual cells that make up the information code are small, or when only part of the information code is illuminated, reading of the added code may be more likely to fail.

[0006] The present disclosure aims to provide an information code and a code reading method that can reduce reading failures.

[0007] In order to achieve the above object, one disclosed embodiment is an information code formed by combining a first code and a second code that record information by a two-dimensional array of multiple cells, and includes light cells, dark cells, semi-light cells that are closer in color to the light cells than the dark cells, and are judged to be the same as the light cells when reading the first code, and are judged to be dark cells when reading the second code, and semi-dark cells that are closer in color to the dark cells than the light cells, and are judged to be the same as the dark cells when reading the first code, and are judged to be light cells when reading the second code, and the second code is enlarged relative to the first code, and one cell of the second code is an information code that is composed across multiple cells of the first code.

[0008] Another disclosed aspect is a code reading method for reading a second code from an information code formed by combining a first code and a second code, each of which records information using a two-dimensional array of multiple cells, the code reading method including, in processing performed by at least one processing unit, the steps of: defining semi-light cells, which are closer in color to light cells than dark cells, as dark cells; defining semi-dark cells, which are closer in color to dark cells than light cells, as light cells; and reading the second code by treating multiple cells in the first code as one cell.

[0009] In these embodiments, since the second code is enlarged relative to the first code, the size of the cells of the second code is larger than the size of the cells of the first code, and therefore, even for an information code that includes semi-dark cells and semi-light cells, it is possible to reduce reading failures.

[0010] Another disclosed embodiment is an information code formed by combining a first code and a second code that record information using a two-dimensional array of multiple cells, and includes light cells, dark cells, semi-light cells that are closer in color to the light cells than the dark cells and are judged to be the same as the light cells when the first code is read and are judged to be dark cells when the second code is read, and semi-dark cells that are closer in color to the dark cells than the light cells and are judged to be the same as the dark cells when the first code is read and are judged to be light cells when the second code is read, and the second code is smaller in size than the first code and is an information code that is combined in the center of the first code.

[0011] Another disclosed aspect is a code reading method for reading a second code from an information code formed by combining a first code and a second code, which record information using a two-dimensional array of multiple cells, and includes the steps of: identifying a formation range of the second code combined in the center of the first code; and, among the cells in the formation range, designating semi-light cells whose color is closer to the light cells than the dark cells as dark cells; and designating semi-dark cells whose color is closer to the dark cells than the light cells as light cells, in processing performed by at least one processing unit.

[0012] In these embodiments, the second code is smaller than the first code and is centered on the first code. Therefore, the semi-dark cells and semi-light cells are not formed near the outer edge of the information code. By avoiding the outer edge, which is susceptible to light, it is possible to reduce the chance of reading failure even for information codes that include semi-dark cells and semi-light cells.

[0013] It should be noted that the reference numerals in parentheses in the claims merely indicate examples of correspondence with specific configurations in the embodiments described below, and do not limit the technical scope in any way. Furthermore, claims not explicitly stated in the claims may be combined together unless there is a particular problem with the combination. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 illustrates an information code according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram showing an overall view of a case where a traceability system is operated together with an existing distribution management system. [Figure 3] FIG. 10 is a diagram for explaining details of a synthesis area into which a confidentiality code is synthesized. [Figure 4] 10A and 10B are diagrams for explaining details of the magnification rate set for the confidentiality code. [Figure 5] 2 is an enlarged view of an area V of the information code in FIG. 1. [Figure 6] FIG. 10 is a diagram for explaining rules for combining a public code and a confidential code. [Figure 7] 10 is a flowchart showing details of a code generation process performed by a history management server. [Figure 8] 10 is a flowchart showing details of a code reading process performed by a code scanner or the like. [Figure 9] 10A and 10B are diagrams illustrating details of image processing for extracting a confidentiality code from an information code. [Figure 10] 10A and 10B are diagrams for explaining the influence of light that occurs when reading a secret code. [Figure 11] 10 is a diagram for explaining details of the magnification rate set in the confidentiality code of the first modified example. FIG. [Figure 12] FIG. 10 is a diagram showing details of a synthesis area set in an information code of Modification 2. [Figure 13] 10 is a diagram for explaining details of the magnification rate set in the confidentiality code of the second modification. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] The information code CQ2 according to an embodiment of the present disclosure shown in FIG. 1 is generated by a process of combining two two-dimensional codes. The two-dimensional code that is the basis of the information code CQ2 is, for example, a QR Code (registered trademark), and records information using a two-dimensional array of multiple cells Ce. The information code CQ2 is printed on a paper medium or the like and is used in the form of a code printing medium such as a label, sticker, or tag. The information code CQ2 may be displayed on a display device such as a display or electronic paper.

[0016] The information code CQ2 of this embodiment is generated by combining the public code Cd1 and the confidentiality code Cd2. When the information code CQ2 is read using a normal reader such as the code reader 13 (see FIG. 2) described later, the information code CQ2 is recognized as the public code Cd1. In this case, the information recorded in the public code Cd1 (hereinafter referred to as public information) is read. On the other hand, the confidentiality code Cd2 can be read by using a special reader such as the code scanner 23 (see FIG. 2) described later. In this case, the information recorded in the confidentiality code Cd2 (hereinafter referred to as confidential information) is read.

[0017] The information code CQ2 is used in both the distribution management system 110 and the traceability system 120 shown in FIG. 2. The distribution management system 110 and the traceability system 120 are management systems that manage a supply chain SC that is constructed including a large number of traders TR. The supply chain SC is a connection between traders for delivering industrial products, agricultural products, marine products, etc. to end users. As an example, in a supply chain SC for delivering agricultural products to consumers, the traders TR include a farmer TR1, an agricultural cooperative TR2 that serves as a collection facility, a transporter TR3, and a retailer TR4.

[0018] The distribution management system 110 collects transaction records of transaction items between traders TR using a public code Cd1. In other words, the public code Cd1 is a QR code operated by the distribution management system 110. The distribution management system 110 is composed of an input terminal 11, a label printer 12, a code reader 13, a system server 10, etc. The input terminal 11, label printer 12, and code reader 13 are appropriately installed in the facilities of each trader TR. The input terminal 11, label printer 12, and code reader 13 are connected via a network to the system server 10 installed in a data center or the like.

[0019] The input terminal 11 is, for example, a personal computer or a tablet terminal. Basic information (hereinafter referred to as item information) of a trade item supplied to the supply chain SC is input to the input terminal 11 in a predetermined format. For example, the item information may include the product name, place of production, production equipment, and manufacturer. The input terminal 11 transmits the item information of the trade item shipped from the trader TR to the system server 10.

[0020] The label printer 12 is an output device for printing the disclosure code Cd1 on a paper medium. The label printer 12 is capable of printing in color or grayscale. The paper medium on which the disclosure code Cd1 is printed is affixed to the package or outer box of the trade item to be shipped, and is distributed as an attachment to the trade item.

[0021] The code reader 13 is a reading device that reads the public code Cd1 to obtain the public information recorded in the public code Cd1. The code reader 13 obtains the public information recorded in the public code Cd1 and transmits the obtained public information to the system server 10.

[0022] The system server 10 is a host node capable of communicating with the input terminal 11, label printer 12, and code reader 13. The system server 10 registers item information acquired from the input terminal 11 in a database. The system server 10 prepares public information linked to the item information and generates a public code Cd1 that records this public information. As part of the process of issuing the public code Cd1, the system server 10 transmits image data, etc. of the generated public code Cd1 to the label printer 12, which is the sender of the item information. When the issued public code Cd1 is circulated together with a transaction item and is read by the code reader 13 of another transactor TR, the system server 10 accumulates a transaction record of the transaction item by this transactor TR.

[0023] The traceability system 120 is used in conjunction with the distribution management system 110, and accumulates transaction records in the same way as the distribution management system 110. Specifically, the distribution management system 110 corresponds to the old management system, and the traceability system 120 corresponds to the new management system. The traceability system 120 is operated together with the existing distribution management system 110 without making any substantial changes to the distribution management system 110. In addition to a record generation function that accumulates transaction records, the traceability system 120 also has a record reference function that makes the accumulated transaction records available for reference. The traceability system 120 uses blockchain technology to manage transaction records in order to prevent tampering with the transaction records.

[0024] The traceability system 120 collects transaction records using an information code CQ2 based on a public code Cd1 issued by the system server 10. The traceability system 120 is composed of a code output device 22, a code scanner 23, a history management server 20, etc. Furthermore, the traceability system 120 uses an input terminal 11 and a label printer 12, etc. of the distribution management system 110. The code output device 22, the code scanner 23, and the input terminal 11 are connected via a network to the history management server 20 installed in a data center or the like.

[0025] The code output device 22 is installed at the facility of the trader TR where the label printer 12 is installed. The code output device 22 is installed so as to interrupt the communication line between the system server 10 and the label printer 12, and acquires the data of the disclosure code Cd1 sent from the system server 10 to the label printer 12. The code output device 22 transmits the acquired data of the disclosure code Cd1 to the history management server 20.

[0026] The code output device 22 receives from the history management server 20 the data of the information code CQ2, which is generated based on the transmitted public code Cd1. The information code CQ2 further records confidential information used in the traceability system 120. The code output device 22 transmits the data of the information code CQ2 to the label printer 12, replacing the data of the public code Cd1. With the intervention of the code output device 22, the label printer 12 prints the information code CQ2 on a paper medium without recognizing that the acquired code data has been altered (replaced). As a result, a code printing medium with the printed information code CQ2 is affixed to a transaction item instead of the public code Cd1, and is distributed together with the transaction item.

[0027] The code scanner 23 is a reading device that reads the information recorded in the information code CQ2, i.e., the secret information added to the information code CQ2 separately from the public information. The code scanner 23 is configured to scan the same object as the code reader 13, and therefore may be physically integrated with the code reader 13. The code scanner 23 is composed of an image sensor formed by a two-dimensional array of CCD elements, a signal processing unit 41, etc. The image sensor is capable of reading information recorded in a plane with a higher resolution than the code reader 13. The image sensor outputs an image showing the information code CQ2 (hereinafter referred to as a code image) to the signal processing unit 41.

[0028] The signal processing unit 41 has a memory unit that stores a code reading program and the like, a processor that executes the code reading process (see FIG. 7) described below based on the code reading program, and RAM. The signal processing unit 41 decodes the read signal (code image) from the image sensor according to a predetermined rule through the code reading process, and acquires the confidential information recorded in the information code CQ2. Based on the acquired confidential information, the signal processing unit 41 communicates with the history management server 20 to keep a transaction record.

[0029] Note that a smartphone 23s (see FIG. 10) or a tablet terminal or the like having a camera function may be used as the code scanner 23. In such a case, a dedicated application equivalent to a code reading program (hereinafter, a code reading application) is provided and installed on the smartphone 23s or the like. The code reading application reads the public code Cd1 in addition to reading the confidential code Cd2.

[0030] The history management server 20 is a host node capable of communicating with the input terminal 11 in addition to the code output device 22 and the code scanner 23. The history management server 20 is mainly configured as a computer including a processing unit 31, RAM 32, a storage unit 33, an input / output interface, and a bus connecting these. The processing unit 31 is hardware for arithmetic processing coupled to the RAM 32. The processing unit 31 accesses the RAM 32 to execute various processes related to data management. The storage unit 33 stores a code generation program, as one of the management programs related to data management, for causing the processing unit 31 to execute the code generation method according to the present disclosure.

[0031] The history management server 20 acquires item information sent from the input terminal 11 to the system server 10. Based on the acquired item information, the history management server 20 generates a blockchain linked to the traded item, which stores the item information and transaction records. When the history management server 20 acquires a notification from the code scanner 23 of each trader TR that the information code CQ2 has been read, the history management server 20 accumulates the transaction record of the trader TR that sent the notification in the blockchain linked to the traded item.

[0032] Specifically, when the history management server 20 receives a notification from the code scanner 23, it generates a new block that stores the transaction records of the notifying transactor TR. The new block contains not only the current transaction record but also a hash value calculated from the previous block. A hash function such as SHA-256 is used to generate the hash value. The hash value is data that maintains a predetermined number of bits (e.g., 256 bits) and reflects item information and transaction records.

[0033] Based on the data of the public code Cd1 acquired from the code output device 22, the history management server 20 performs the code generation process (see FIG. 6) described below to generate an information code CQ2 that records at least the above-mentioned hash value as confidential information. The history management server 20 issues the generated information code CQ2 to the code output device 22. As a result, the hash value that reflects the item information and transaction record is recorded in the information code CQ2, which can be circulated together with the transaction item.

[0034] In the traceability system 120, a single information code CQ2 may be continuously used across multiple traders TR, or a new information code CQ2 may be issued for each trader TR. In a case where a new information code CQ2 is issued for each trader TR, a new hash value reflecting the transaction record is generated based on the occurrence of a transaction record at each trader TR. The history management server 20 generates a new information code CQ2 that records the new hash value as confidential information and provides the data of the new information code CQ2 to the label printer 12 at the facility of the trader TR that conducted the transaction. As a result, as the transaction of an item progresses, the content (hash value) of the information code CQ2 is continually updated to reflect the transaction record up to that point. Furthermore, because the confidential information is primarily based on the hash value, the amount of confidential information data can be maintained constant even as the transaction of an item progresses in the supply chain SC.

[0035] The history management server 20 can further issue a tracing code QRt. The tracing code QRt is a two-dimensional code such as a QR code attached to the final product FP supplied by the supply chain SC. The tracing code QRt enables the consumer who has acquired the final product FP to check the transaction record. As an example, the tracing code QRt records a hash value calculated from the last block of the blockchain and an IP address or URL indicating the contact point for inquiries about the transaction record.

[0036] A consumer of the final product FP can view the transaction record of the final product FP by using a user terminal 50, such as a smartphone or tablet terminal, and a traceability confirmation app. Specifically, the user terminal 50 reads the tracing code QRt attached to the final product FP and sends a transaction record reference request along with a hash value to the history management server 20, which is the contact point for inquiries. Upon receiving the reference request, the history management server 20 extracts the item information and transaction record linked to the hash value and generates data to be provided. The history management server 20 transmits the generated data to the user terminal 50, which is the source of the reference request. A consumer of the final product FP can use the traceability confirmation app to open the data to be provided received from the history management server 20 and check the history of the transaction record.

[0037] Next, the information code CQ2 will be further described in detail with reference to FIG. 1 and FIGS.

[0038] As described above, the information code CQ2 is generated by a process of combining the public code Cd1 and the concealment code Cd2 (see Figure 1). The public code Cd1 and the concealment code Cd2 each record information using a two-dimensional array of white cells Cew and black cells Ceb. The public code Cd1 and the concealment code Cd2 are two-dimensional codes with different numbers of cells (versions). The concealment code Cd2 is a two-dimensional code with a smaller size than the public code Cd1. In other words, the public code Cd1 is a two-dimensional code with a larger version than the concealment code Cd2. Therefore, the number of cells in the public code Cd1 is greater than the number of cells in the concealment code Cd2. The information code CQ2, which is formed by overlapping the concealment code Cd2 on the public code Cd1, is a two-dimensional code with the same number of cells (version) as the public code Cd1.

[0039] The confidentiality code Cd2 is enlarged by an integral multiple of the public code Cd1 and then combined with the public code Cd1. Therefore, one cell Ce of the confidentiality code Cd2 is combined across multiple cells Ce of the public code Cd1. For example, when the confidentiality code Cd2 is enlarged by two times, the enlarged cell Ce is overlapped with four (2 × 2) cells Ce of the public code Cd1. At this time, the four sides of the enlarged cell Ce are overlapped with the four outer boundaries without any misalignment. The confidentiality code Cd2 is overlapped with the center of the public code Cd1, avoiding the specific area SA (see Figure 3) of the public code Cd1. For example, the finder pattern FiP and format information area FiA of the public code Cd1 are at least the specific area SA.

[0040] The finder pattern FiP is a pattern for detecting the position of the two-dimensional code (public code Cd1), and is a square formed at three of the four corners of the two-dimensional code. The format information area FiA is an area that records format information for the two-dimensional code, specifically, information indicating the error correction level and mask pattern. The format information area FiA is defined in an I-shape or L-shape at the desired position for each finder pattern FiP.

[0041] By avoiding the specific area SA, the central area of ​​the public code Cd1, excluding the 8 or 9 cells facing the four outer edges, becomes the composite area CA where the concealment code Cd2 can be placed. In other words, the number of cells in the composite area CA is 17 cells less vertically and horizontally than the number of cells in the public code Cd1. The composite area CA is arranged to avoid not only the finder pattern FiP and format information area FiA described above, but also the version information area ViA, timing pattern TiP, and some alignment patterns AlP. The version information area ViA is an area where information indicating the version of the 2D code is recorded. The version information area ViA is defined to be located facing the two diagonally arranged finder patterns FiP.

[0042] The expansion rate of the concealment code Cd2 is set so that the enlarged concealment code Cd2 (hereinafter referred to as the enlarged code Cde) fits within the combining area CA. Therefore, the expansion rate of the concealment code Cd2 is determined based on the versions of the public code Cd1 and the concealment code Cd2 to be combined (see FIG. 4). As an example, if the version of the public code Cd1 is 17 (85×85 cells), the combining area CA will be 68×68 in size. In this case, if the version of the concealment code Cd2 is 4 (33×33 cells), an expansion rate of 2x can be set (see the dashed square in FIG. 4).

[0043] The information code CQ2 includes a white cell Cew and a black cell Ceb, as well as a light color cell Cc1 (see the light gray area in Figures 1 and 5) and a dark color cell Cc2 (see the dark gray area in Figures 1 and 5). The light color cell Cc1 and the dark color cell Cc2 are located only in the composition area CA. The information code CQ2 holds both public and private information through a two-dimensional arrangement of the white cell Cew, the black cell Ceb, the light color cell Cc1, and the dark color cell Cc2. Each cell Ce in the information code CQ2 is determined based on the combination of the white cell Cew and the black cell Ceb in the public code Cd1 and the private code Cd2 (see Figure 6).

[0044] Specifically, a cell Ce at a position where both the public code Cd1 and the secret code Cd2 are black cells Ceb also becomes black cells Ceb with the information code CQ2. Similarly, a cell Ce at a position where both the public code Cd1 and the secret code Cd2 are white cells Cew also becomes white cells Cew with the information code CQ2.

[0045] On the other hand, a cell Ce where the public code Cd1 is a black cell Ceb and the confidentiality code Cd2 is a white cell Cew becomes a dark color cell Cc2 (see the hatched area in Figure 6). Also, a cell Ce where the public code Cd1 is a white cell Cew and the confidentiality code Cd2 is a black cell Ceb becomes a light color cell Cc1 (see the dotted area in Figure 6). The dark color cell Cc2 is a cell Ce with a chromatic color whose brightness is closer to that of the black cell Ceb than to that of the white cell Cew, but lower than that of the light color cell Cc1. For example, red, blue, green, etc. are used as the color of the dark color cell Cc2. The light color cell Cc1 is a cell Ce with a chromatic color whose brightness is closer to that of the white cell Cew than to that of the black cell Ceb, but higher than that of the dark color cell Cc2. For example, yellow, etc. is used as the color of the light color cell Cc1.

[0046] For the information code CQ2, the dark gray cell Cg2 and the light gray cell Cg1 can be used instead of the dark color cell Cc2 and the light color cell Cc1. If the label printer 12 is configured to be unable to output color but is capable of grayscale output, the dark gray cell Cg2 and the light gray cell Cg1 are used. The dark gray cell Cg2 is an achromatic cell Ce that is closer to the black cell Ceb than to the white cell Cew and has a lower brightness than the light gray cell Cg1. For example, a dark gray with a brightness approximately 25% that of the white cell Cew is used as the color of the dark gray cell Cg2. The light gray cell Cg1 is an achromatic cell Ce that is closer to the white cell Cew than to the black cell Ceb and has a higher brightness than the dark gray cell Cg2. For example, a light gray with a brightness approximately 75% that of the white cell Cew is used as the color of the light gray cell Cg1.

[0047] Here, the code reader 13 (see FIG. 2) of the distribution management system 110, which corresponds to the old management system, detects the brightness of each cell Ce, in other words, the light reflectance of each cell Ce, when reading the information code CQ2. Therefore, the code reader 13 distinguishes the light color cell Cc1 and the light gray cell Cg1 as white cells Cew, and the dark color cell Cc2 and the dark gray cell Cg2 as black cells Ceb. As a result, the code reader 13 recognizes the information code CQ2 as a two-dimensional code that is substantially the same as the public code Cd1, and can read the public information.

[0048] Next, the details of the code generation process (code generation method) for generating the information code CQ2 explained above will be described below based on FIG. 7 and with reference to FIGS. 1, 2, and 4 to 6.

[0049] In the code generation process, first, a public code Cd1 and a confidential code Cd2 are prepared. Specifically, in S11, the history management server 20 acquires the public code Cd1 by receiving it from the code output device 22. Next, in S12, the history management server 20 acquires a hash value that reflects the item information and transaction record, and prepares confidential information that mainly includes the hash value.

[0050] In S13, the history management server 20 determines the version and magnification rate of the concealment code Cd2 based on the version of the public code Cd1 acquired in S11. As an example, if the version of the public code Cd1 is 17, the version of the concealment code Cd2 is set to 4 or lower. The history management server 20 determines the version and error correction level of the concealment code Cd2 so that the data amount (number of bits) of the concealment information acquired in S12 can be recorded. Then, the signal processing unit 41 further determines the maximum magnification rate that can accommodate the determined concealment code Cd2 in the synthesis area CA.

[0051] In S14, the history management server 20 generates a concealment code Cd2 for the version and error correction level determined in S13. Furthermore, in S15, the history management server 20 enlarges the concealment code Cd2 by the enlargement ratio determined in S13 to generate an enlarged code Cde.

[0052] In S16, the history management server 20 superimposes and combines the enlarged code Cde generated in S15 onto the combination area CA of the disclosure code Cd1 acquired in S11. As described above, in the disclosure code Cd1, the black cells Ceb that overlap with the white cells Cew of the enlarged code Cde are converted into dark color cells Cc2 or dark gray cells Cg2 (see FIG. 6). Also, in the disclosure code Cd1, the white cells Cew that overlap with the black cells Ceb of the enlarged code Cde are converted into light color cells Cc1 or light gray cells Cg1. As a result, an information code CQ2 is generated in which the white cells Cew, black cells Ceb, light color cells Cc1, and dark color cells Cc2 are two-dimensionally arranged. The information code CQ2 generated in this manner is issued to the transactor TR in S17.

[0053] Next, details of the code reading process (code reading method) for reading the concealment code Cd2 from the information code CQ2 will be described below based on FIGS. 8 and 9 and with reference to FIGS. 1 to 3. FIG.

[0054] In S31 of the code reading process, the signal processing unit 41 determines the position and orientation of the information code CQ2 in the captured code image based on the detection of the finder pattern FiP. In S32, the signal processing unit 41 applies preprocessing such as keystone correction and color correction to the area containing the information code CQ2 based on the information on the position and orientation of the information code CQ2, and prepares a processed image (hereinafter referred to as corrected image Pc0) suitable for code reading. The corrected image Pc0 is an image corrected to the shape of the information code CQ2 photographed from the front. In addition, in the corrected image Pc0, the gradation values ​​of the entire image are adjusted so that the gradation values ​​of the white cells Cew and black cells Ceb of the information code CQ2 are approximately the same.

[0055] In S33, the signal processing unit 41 identifies a composite area CA in the information code CQ2 appearing in the corrected image Pc0, where the concealment code Cd2 is composited, and cuts out the identified composite area CA from the information code CQ2. In other words, in S33, the central range in which the light color cell Cc1 and the dark color cell Cc2 are arranged is identified and cut out.

[0056] To identify the synthesis area CA, the signal processing unit 41 first generates a first converted image Pc1 by converting the black cells Ceb of the information code CQ2 to the same white color as the white cells Cew (see FIG. 9). Next, the signal processing unit 41 generates a second converted image Pc2 by converting the light color cells Cc1 and dark color cells Cc2 of the first converted image Pc1 to the same black color as the black cells Ceb. Furthermore, the signal processing unit 41 generates an inverted image Pc3 by inverting the light and dark colors (black and white) in the second converted image Pc2. The signal processing unit 41 identifies the synthesis area CA based on the range of light colors (white) in the inverted image Pc3. More specifically, the signal processing unit 41 determines the coordinates of a pair of diagonally opposite corners in the white range of the inverted image Pc3 by labeling the inverted image Pc3. The signal processing unit 41 acquires the pair of coordinates as coordinates indicating the formation range of the synthesis area CA. Based on the acquired coordinates, the signal processing unit 41 cuts out a cut-out image Pc4 including the concealment code Cd2 from the synthesis area CA of the corrected image Pc0.

[0057] In S34, the signal processing unit 41 applies a color conversion process to extract the concealment code Cd2 from the cut-out image Pc4. Specifically, the signal processing unit 41 converts the light color cell Cc1 of the cells Ce in the synthesis area CA into a black cell Ceb and the dark color cell Cc2 into a white cell Cew to generate an extracted image Pc5 from which the concealment code Cd2 has been extracted. Furthermore, the signal processing unit 41 expands and contracts the black areas in the extracted image Pc5 to remove noise and wormholes from the extracted image Pc5. By applying this correction process to the extracted image Pc5, the signal processing unit 41 generates a restored image Pc6 from which the concealment code Cd2 has been restored.

[0058] In S35, the signal processing unit 41 reads the restored image Pc6 as the concealment code Cd2, reads the concealment information, and then ends the code reading process. At this time, in the restored image Pc6, one cell Ce of the concealment code Cd2 has a size equivalent to the number of cells Ce of the public code Cd1. Therefore, the signal processing unit 41 reads the concealment code Cd2 by treating the number of cells Ce in the public code Cd1 as one cell Ce. This makes it easy to read the concealment information from the restored image Pc6.

[0059] The code reading process may be performed by the history management server 20. In this embodiment, the code captured image or corrected image Pc0 is transmitted from the code scanner 23 to the history management server 20. The history management server 20 then performs a process of reading the concealment code Cd2 from the code captured image or corrected image Pc0 that it has received. Furthermore, even if light gray cells Cg1 and dark gray cells Cg2 are used instead of the light color cells Cc1 and dark color cells Cc2, the concealment code Cd2 can still be restored by the above process.

[0060] In the embodiment described so far, the confidentiality code Cd2 is enlarged relative to the public code Cd1, so the size of the cell Ce of the confidentiality code Cd2 is larger than the size of the cell Ce of the public code Cd1. Therefore, even for the information code CQ2 that includes the dark color cell Cc2 and the light color cell Cc1, it is possible to reduce the failure to read the code.

[0061] More specifically, the smaller the size of each cell Ce of a two-dimensional code, the more difficult it becomes to read. In particular, the finer the information code CQ2, which includes the light color cell Cc1 and the dark color cell Cc2, the worse the recognition performance becomes. To address this issue, in this embodiment, a smaller version of the secret code Cd2 than the public code Cd1 is enlarged relative to the public code Cd1 and then combined with the public code Cd1. In this way, by enlarging the secret code Cd2 during combination, the size of each cell Ce can be ensured, and therefore, even if the code includes the light color cell Cc1 and the dark color cell Cc2, deterioration in recognition performance can be suppressed.

[0062] Additionally, in this embodiment, the confidential information recorded in the confidentiality code Cd2 is mainly composed of hash values. Therefore, the amount of information that needs to be recorded as confidential information is reduced, making it possible to reduce the version of the confidentiality code Cd2. As described above, the method of improving recognizability by expanding the confidentiality code Cd2 is suitable for the traceability system 120 that records hash values ​​as confidential information.

[0063] Furthermore, in this embodiment, the confidentiality code Cd2 is enlarged by an integral multiple of the public code Cd1 and then combined with the public code Cd1. This prevents a situation in which multiple cells Ce of the confidentiality code Cd2 are combined with one cell Ce of the public code Cd1. As a result, the recognizability of the public code Cd1 can be ensured, thereby reducing failures in reading the public code Cd1.

[0064] Furthermore, in this embodiment, the confidentiality code Cd2 is smaller than the public code Cd1 and is combined with the center of the public code Cd1. Therefore, the dark color cells Cc2 and the light color cells Cc1 are not formed near the outer edges of the information code CQ2. By avoiding the outer edges, which are easily affected by light, it is possible to reduce the chance of reading failure even with an information code CQ2 that includes the dark color cells Cc2 and the light color cells Cc1.

[0065] Specifically, as shown in Figure 10, when reading an information code CQ2 printed on a label or the like using a code reading app on a smartphone 23s, light enters the label from the periphery of the smartphone 23s, causing light effects near the outer edge of the information code CQ2. As a result, a highlight-like phenomenon occurs around the periphery of the public code Cd1 read from the information code CQ2 (see the elliptical area in Figure 10). If this light effect extends to the light color cell Cc1, it becomes difficult to distinguish between the light color cell Cc1 and the white cell Cew. Therefore, the light color cell Cc1, which should be converted to the black cell Ceb, is likely to be mistaken for the white cell Cew due to the light effect. As a result, it becomes difficult to convert the color cells Cc1 and Cc2 back to the black cell Ceb and the white cell Cew. Similar issues can arise even when using a code scanner 23.

[0066] However, in this embodiment, the size of the concealment code Cd2 (enlarged code Cde) is set so that the public code Cd1 is larger, and the concealment code Cd2 is placed in the center of the public code Cd1. Therefore, the influence of light is less likely to reach the color cells Cc1 and Cc2. As a result, the process of returning the color cells Cc1 and Cc2 to the black cells Ceb and the white cells Cew can be reliably performed, thereby reducing the chance of failure to read the concealment code Cd2.

[0067] Furthermore, as the version of the information code CQ2 increases, the distance between the code scanner 23 or smartphone 23s and the information code CQ2 tends to increase in order to read the entire information code CQ2. This allows more light to enter the outer edge of the information code CQ2. However, by arranging the concealment code Cd2 in the center as described above, the influence of light on each of the color cells Cc1 and Cc2 can be suppressed. As described above, arranging the concealment code Cd2 in the center of the public code Cd1 is more effective in reducing code reading failures as the version of the public code Cd1 increases.

[0068] Additionally, in this embodiment, the concealment code Cd2 is combined with the public code Cd1, avoiding the specific area SA of the public code Cd1. Specifically, the finder pattern FiP and the format information area FiA are set as the specific area SA, and the light color cells Cc1 and the dark color cells Cc2 are not placed in the finder pattern FiP or the format information area FiA. This prevents deterioration in the recognizability of the public code Cd1, thereby reducing failures in reading the public code Cd1.

[0069] In this embodiment, in the step of identifying the composite area CA, a first converted image Pc1 is generated by converting the black cells Ceb of the information code CQ2 to the same color as the white cells Cew. Furthermore, a second converted image Pc2 is generated by converting each color cell Cc1 and Cc2 of the first converted image Pc1 to the same color as the black cells Ceb, and an inverted image Pc3 is generated by inverting the brightness of the colors in the second converted image Pc2. The composite area CA is then identified based on the range of bright colors in the inverted image Pc3. As described above, image processing that blackens each color cell Cc1 and Cc2 and then performs black-and-white inversion can speed up the process of identifying the formation range of each color cell Cc1 and Cc2. As a result, confidential information can be quickly read from the information code CQ2.

[0070] In the above embodiment, the signal processing unit 41 corresponds to a "processing unit" that performs the code reading method, the public code Cd1 corresponds to a "first code", and the concealment code Cd2 corresponds to a "second code". Also, the white cell Cew corresponds to a "light cell", the black cell Ceb corresponds to a "dark cell", the light color cell Cc1 or the light gray cell Cg1 corresponds to a "semi-light cell", and the dark color cell Cc2 or the dark gray cell Cg2 corresponds to a "semi-dark cell". Furthermore, the synthesis area CA corresponds to a "forming range".

[0071] Further technical ideas that can be understood from the embodiments described above are described below as Supplementary Notes 1 to 6. (Appendix 1) A first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional array of a plurality of cells (Ce) are prepared (S11 to S14). generating an information code (CQ2) by combining the first code and the second code (S15, S16); The process performed by at least one processing unit (31) includes the steps of: In the step of combining the first code and the second code, Expanding the second code relative to the first code to synthesize one cell of the second code across multiple cells of the first code; The cell at a position where both the first code and the second code are light-colored cells (Cew) is defined as the light-colored cell, The cell at a position where both the first code and the second code are dark cells (Ceb) is defined as the dark cell, The cells at the positions where the first code is the light cell and the second code is the dark cell are defined as semi-light cells (Cc1, Cg1) whose color is closer to the light cell than the dark cell; A code generation method in which the cell at a position where the first code is the dark cell and the second code is the light cell is set to a semi-dark cell (Cc2, Cg2) whose color is closer to the dark cell than the light cell. (Appendix 2) A first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional array of a plurality of cells (Ce) are prepared (S11 to S14), generating an information code (CQ2) by combining the first code and the second code (S16); The process performed by at least one processing unit (31) includes the steps of: In the step of combining the first code and the second code, The second code, which is smaller than the first code, is synthesized at the center of the first code; The cell at a position where both the first code and the second code are light-colored cells (Cew) is defined as the light-colored cell, The cell at a position where both the first code and the second code are dark cells (Ceb) is defined as the dark cell, The cells at the positions where the first code is the light cell and the second code is the dark cell are defined as semi-light cells (Cc1, Cg1) whose color is closer to the light cell than the dark cell; A code generation method in which the cell at a position where the first code is the dark cell and the second code is the light cell is set to a semi-dark cell (Cc2, Cg2) whose color is closer to the dark cell than the light cell. (Appendix 3) A code generating device that generates an information code (CQ2) that is a combination of a first code (Cd1) and a second code (Cd2) that record information using a two-dimensional array of a plurality of cells (Ce), a code preparation unit (S11 to S14) that prepares the first code and the second code; a code synthesis unit (S15, S16) that generates the information code by synthesizing the first code and the second code, The code synthesis unit Expanding the second code relative to the first code to synthesize one cell of the second code across multiple cells of the first code; The cell at a position where both the first code and the second code are light-colored cells (Cew) is defined as the light-colored cell, The cell at a position where both the first code and the second code are dark cells (Ceb) is defined as the dark cell, The cells at the positions where the first code is the light cell and the second code is the dark cell are defined as semi-light cells (Cc1, Cg1) whose color is closer to the light cell than the dark cell; A code generation device that sets the cell at a position where the first code is the dark cell and the second code is the light cell as a semi-dark cell (Cc2, Cg2) whose color is closer to the dark cell than the light cell. (Appendix 4) A code generating device that generates an information code (CQ2) that is a combination of a first code (Cd1) and a second code (Cd2) that record information using a two-dimensional array of a plurality of cells (Ce), a code preparation unit (S11 to S14) that prepares the first code and the second code; a code synthesis unit (S16) that generates the information code by synthesizing the first code and the second code, The code synthesis unit The second code, which is smaller than the first code, is synthesized at the center of the first code; The cell at a position where both the first code and the second code are light-colored cells (Cew) is defined as the light-colored cell, The cell at a position where both the first code and the second code are dark cells (Ceb) is defined as the dark cell, The cells at the positions where the first code is the light cell and the second code is the dark cell are defined as semi-light cells (Cc1, Cg1) whose color is closer to the light cell than the dark cell; A code generation device that sets the cell at a position where the first code is the dark cell and the second code is the light cell as a semi-dark cell (Cc2, Cg2) whose color is closer to the dark cell than the light cell. (Appendix 5) A code reading device that reads a second code from an information code (CQ2) that is a combination of a first code (Cd1) and a second code (Cd2) that record information using a two-dimensional array of a plurality of cells (Ce), comprising: an image acquisition unit (S31) that acquires a code image showing the information code; and an image conversion unit (S34, S35) that converts, among the cells of the information code, semi-light cells (Cc1, Cg1) whose color is closer to the light cells (Cew) than the dark cells (Ceb) into dark cells, and converts semi-dark cells (Cc2, Cg2) whose color is closer to the dark cells than the light cells into light cells, The image conversion unit is a code reading device that reads the second code by treating multiple cells in the first code as one cell. (Appendix 6) A code reading device that reads a second code from an information code (CQ2) that is a combination of a first code (Cd1) and a second code (Cd2) that record information using a two-dimensional array of a plurality of cells (Ce), comprising: an image acquisition unit (S31) that acquires a code image showing the information code; an image conversion unit (S33, S34) that specifies a formation range (CA) of the second code combined at the center of the first code, and among the cells in the formation range, defines semi-light cells (Cc1, Cg1) whose color is closer to the light cell (Cew) than the dark cell (Ceb) as dark cells, and defines semi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell as light cells; A code reading device comprising: In the above embodiment, the history management server 20 corresponds to the "code generating device", and the history management server 20 or the code scanner 23 corresponds to the "code reading device".

[0072] (Other embodiments) Although one embodiment of the present disclosure has been described above, the present disclosure should not be construed as being limited to the above embodiment, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0073] In the first modification of the above embodiment, the entire area of ​​the information code CQ2 can be used as the synthesis area CA. In other words, in the first modification, a specific area SA where synthesis should be avoided is not set. As a result, a larger magnification ratio can be set for the concealment code Cd2 than in the above embodiment. As an example, an enlarged code Cde obtained by enlarging the concealment code Cd2 of version 4 by a factor of two can be synthesized with the public code Cd1 of version 13 (see the dashed square in FIG. 11). As a result, in the first modification, the recognizability of the concealment code Cd2 can be further improved.

[0074] In a second modification of the above embodiment, as shown in FIG. 12, a synthesis area CA is offset to one of the four corners of the information code CQ2 where no finder pattern FiP is present. In the second modification, the synthesis area CA can be larger than in the above embodiment, in which the synthesis area CA is set in the center of the information code CQ2. The number of cells in the synthesis area CA is 9 cells less vertically and 8 cells less horizontally than the number of cells in the public code Cd1. For example, if the public code Cd1 is version 15 (77 × 77 cells), the synthesis area CA will be 68 × 69 in size. In this case, it is possible to synthesize an expanded code Cde, which is twice the size of the version 4 confidentiality code Cd2 (33 × 33 cells) (see the dashed square in FIG. 13).

[0075] The above first and second modifications also have the same effect as the above embodiment, and by enlarging the confidentiality code Cd2, it is possible to reduce failures in reading the code.

[0076] In the third modification of the above embodiment, the process of enlarging the confidentiality code Cd2 is omitted. The confidentiality code Cd2 is composited into the composite area CA in the center of the public code Cd1 so as to avoid the specific area SA. In the third modification, the light color cell Cc1 and the dark color cell Cc2 are not positioned near the outer edge of the information code CQ2, so that the deterioration of recognizability due to the influence of light can be avoided.

[0077] In the fourth variation of the above embodiment, the method for identifying the synthesis area CA during the code reading process differs from that of the above embodiment. In the fourth variation, the signal processing unit 41 begins searching for the light color cell Cc1 and the dark color cell Cc2 from a pair of diagonally opposite corners (e.g., the upper left corner and the lower right corner) of the information code CQ2. The signal processing unit 41 then cuts out the cut-out image Pc4, using the positions where the light color cell Cc1 and the dark color cell Cc2 are detected as coordinates indicating the formation range of the synthesis area CA. This method also makes it possible to determine the coordinates of the pair of corners.

[0078] In a fifth modification of the above embodiment, a non-integer magnification ratio (for example, 1.5 times) is set. The boundary of a cell Ce of the concealment code Cd2 may be located within one cell Ce of the concealment code Cd1, provided that this does not interfere with the code reader 13 used in the distribution management system 110 from reading the disclosure code Cd1. Furthermore, in the above embodiment, the concealment code Cd2 is synthesized such that the boundary of the cell Ce of the concealment code Cd2 (enlarged code Cde) overlaps with the boundary of the cell Ce of the disclosure code Cd1. However, as long as the code can be read, the boundary of the cell Ce of the concealment code Cd2 may be shifted from the boundary of the cell Ce of the disclosure code Cd1.

[0079] In the above embodiment, the light color forming the white cell Cew does not have to be strictly white. For example, the color of the base material of the label on which the information code CQ2 is printed (e.g., very light gray or ivory) can correspond to the light color. Similarly, the dark color forming the black cell Ceb does not have to be strictly black. For example, the color of the ink used in the label printer 12 (e.g., dark navy blue or dark green) can correspond to the dark color.

[0080] The public code Cd1 and the secret code Cd2 are not limited to QR codes. Two-dimensional codes different from QR codes may be used as the first code and the second code and combined into the information code. Furthermore, when QR codes are used as each code, the error correction capabilities (error correction levels) may be different from each other.

[0081] The information code CQ2 according to the present disclosure may be used by a system different from the distribution management system 110 and the traceability system 120. Furthermore, the information recorded in the first code and the second code that are the basis of the information code is not limited to the above-mentioned public information and confidential information, and may be changed as appropriate depending on the use of the information code.

[0082] In the above embodiment, a tracing code QRt is issued and attached to the final product FP, separate from the information code CQ2 used in the supply chain SC. However, the information code CQ2 may be used as the tracing code QRt. In this case, the traceability confirmation application performs the above-described code reading process and provides the user terminal 50 with a function for reading the concealment code Cd2. Furthermore, the final product FP supplied by the supply chain SC may be changed as appropriate. For example, various items such as automobiles, batteries, semiconductors, fresh produce, seafood, food, flowers, pharmaceuticals, and chemicals can be managed by the traceability system 120.

[0083] The hash function used in the history management server 20 is a cryptographic hash function, which has the property that it never outputs the same hash value from different inputs and that it is virtually impossible to guess the input from the output hash value. For example, instead of the above-mentioned SHA-256, encryption algorithms such as SHA-1, SHA-2, and SHA-3 may be used as appropriate in accordance with the output length (number of bits) that can be recorded in the confidential information in the confidentiality code Cd2. Furthermore, the code generation process performed in the history management server 20 may be performed by a code output device 22 or the like on the edge side. In such a configuration, the code output device 22 corresponds to the "code generation device."

[0084] In the above embodiment, the functions provided by the history management server, code scanner, etc. can be provided by software and hardware that executes it, software only, hardware only, or a combination of these. When such functions are provided by electronic circuits as hardware, each function can also be provided by digital circuits including multiple logic circuits, or analog circuits.

[0085] The processing unit (signal processing unit) in the above embodiment may be configured to include at least one arithmetic core such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit).Furthermore, the processing unit may be configured to further include an FPGA (Field-Programmable Gate Array), an NPU (Neural network Processing Unit), an IP core with other dedicated functions, etc.

[0086] The form of the non-transitory tangible storage medium employed as each storage unit in the above embodiments and storing each program related to code generation and code reading of the present disclosure may be modified as appropriate. For example, the storage medium is not limited to a configuration mounted on a circuit board, but may be provided in the form of a memory card or the like, inserted into a slot, and electrically connected to a computer bus. Furthermore, the storage medium may be an optical disk or hard disk drive from which the program is copied to the computer.

[0087] The controller and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by special-purpose hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers comprising a processor executing a computer program in combination with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

Claims

1. An information code formed by combining a first code (Cd1) and a second code (Cd2) that record information by a two-dimensional array of a plurality of cells (Ce), a light cell (Cew); a dark cell (Ceb); semi-light cells (Cc1, Cg1) that are closer in color to the light cells than the dark cells, are determined to be the same as the light cells when reading the first code, and are determined to be the dark cells when reading the second code; semi-dark cells (Cc2, Cg2) that are closer in color to the dark cells than the light cells, that are determined to be the same as the dark cells when the first code is read, and that are determined to be the light cells when the second code is read, An information code in which the second code is expanded relative to the first code, and one cell of the second code is synthesized across multiple cells of the first code.

2. 2. The information code according to claim 1, wherein the second code is expanded by an integral multiple of the first code and combined with the first code.

3. The information code according to claim 1 , wherein the second code is smaller than the first code and is combined with the first code at the center thereof.

4. An information code formed by combining a first code (Cd1) and a second code (Cd2) that record information by a two-dimensional array of a plurality of cells (Ce), a light cell (Cew); a dark cell (Ceb); semi-light cells (Cc1, Cg1) that are closer in color to the light cells than the dark cells, are determined to be the same as the light cells when reading the first code, and are determined to be the dark cells when reading the second code; semi-dark cells (Cc2, Cg2) that are closer in color to the dark cells than the light cells, that are determined to be the same as the dark cells when the first code is read, and that are determined to be the light cells when the second code is read, The second code is an information code that is smaller in size than the first code and is combined at the center of the first code.

5. The information code according to any one of claims 1 to 4, wherein the second code is synthesized while avoiding a specific area (SA) of the first code.

6. A code reading method for reading a second code from an information code (CQ2) obtained by combining a first code (Cd1) and a second code (Cd2) that record information by a two-dimensional array of a plurality of cells (Ce), the method comprising: The dark cells are semi-bright cells (Cc1, Cg1) whose color is closer to the light cell (Cew) than the dark cell (Ceb), semi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell are defined as the light cells; reading the second code by treating the plurality of cells in the first code as one cell; A code reading method including the steps of:

7. A code reading method for reading a second code from an information code (CQ2) obtained by combining a first code (Cd1) and a second code (Cd2) that record information by a two-dimensional array of a plurality of cells (Ce), the method comprising: Identifying a forming area (CA) of the second cord synthesized at the center of the first cord; Among the cells in the formation range, the semi-light cells (Cc1, Cg1) whose color is closer to the light cell (Cew) than the dark cell (Ceb) are defined as the dark cells, The semi-dark cells (Cc2, Cg2) whose color is closer to the dark cells than the light cells are defined as the light cells. A code reading method including the steps of:

8. In the step of specifying the formation range, generating a first converted image (Pc1) by converting the dark cells of the information code into the same color as the light cells; generating a second converted image (Pc2) by converting the semi-light color cells and the semi-dark color cells of the first converted image into the same color as the dark color cells; generating an inverted image (Pc3) by inverting the brightness of the colors in the second converted image; The code reading method according to claim 7 , wherein the forming range is specified based on a range of light colors in the reverse image.

Images