Information code and code reading method

Abstract

The information code (CQ2) is formed by combining a public code (Cd1) and a hiding code (Cd2) for recording information in a two-dimensional arrangement of a plurality of cells (Ce), and includes a bright color cell (Cc1) and a dark color cell (Cc2) in addition to a white cell (Cew) and a black cell (Ceb). The bright color cells (Cc1) are discriminated in the same manner as white cells (Cew) during the reading of the public code (Cd1), and are discriminated as black cells (Ceb) during the reading of the secret code (Cd2). The dark color cell (Cc2) is discriminated in the same manner as the black cell (Ceb) during reading of the public code (Cd1), and is discriminated as the white cell (Cew) during reading of the secret code (Cd2). The secret code (Cd2) is amplified with respect to the public code (Cd1), and one cell (Ce) of the secret code (Cd2) is synthesized across a plurality of cells (Ce) of the public code (Cd1).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Japanese Patent Application No. 2022-87899 filed in Japan on May 30, 2022, and the entire contents are incorporated herein by reference. Technical Field

[0003] The disclosure of this specification relates to the technology of information codes for recording information. Background Art

[0004] Patent document 1 describes an information code formed by synthesizing other QR codes into a basic QR code (registered trademark). In this information code, in addition to black cells and white cells, light gray cells and dark gray cells are also included, and through the two-dimensional arrangement of these cells, the information recorded in multiple QR codes can be read separately.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-196762

[0006] Gray cells, which are intermediate colors, are more difficult to distinguish than black cells and white cells. Therefore, when each cell forming the information code is thin or when light irradiates only a portion of the information code, reading of the additional code is likely to fail. Summary of the invention

[0007] An object of the present disclosure is to provide an information code and a code reading method capable of reducing reading failures.

[0008] In order to achieve the above-mentioned purpose, a disclosed method is an information code, which is an information code formed by synthesizing a first code and a second code that record information through a two-dimensional arrangement of multiple cells, including: light cells; dark cells; quasi-bright cells, which are colors closer to light cells than dark cells, and are distinguished the same as light cells in reading the first code, and are distinguished as dark cells in reading the second code; and quasi-dark cells, which are colors closer to dark cells than light cells, and are distinguished the same as dark cells in reading the first code, and are distinguished as light cells in reading the second code, the second code is enlarged relative to the first code, and one cell of the second code spans multiple cells of the first code for synthesis.

[0009] Another disclosed method is a code reading method, which is a code reading method that reads a second code from an information code formed by synthesizing a first code and a second code that record information through a two-dimensional arrangement of multiple cells. The method includes the following steps in the processing performed by at least one processing unit: making a quasi-bright cell whose color is closer to a light cell than a dark cell into a dark cell; making a quasi-dark cell whose color is closer to a dark cell than a light cell into a light cell; and reading the second code by treating multiple cells in the first code as one cell.

[0010] In these methods, since the second code is enlarged relative to the first code, the size of the cell of the second code is larger than the size of the cell of the first code. Therefore, even for an information code including quasi-dark cells and quasi-bright cells, the reading failure can be reduced.

[0011] Another disclosed method is an information code, which is an information code formed by synthesizing a first code and a second code that record information through a two-dimensional arrangement of multiple cells, including: light cells; dark cells; quasi-bright cells, which are colors closer to light cells than dark cells, and are distinguished the same as light cells when reading the first code, and are distinguished as dark cells when reading the second code; and quasi-dark cells, which are colors closer to dark cells than light cells, and are distinguished the same as dark cells when reading the first code, and are distinguished as light cells when reading the second code, and the second code is smaller in size than the first code and is synthesized in the center of the first code.

[0012] Another disclosed method is a code reading method, which is a code reading method that reads a second code from an information code formed by synthesizing a first code and a second code that record information through a two-dimensional arrangement of multiple cells. The processing implemented by at least one processing unit includes the following steps: determining a formation range of the second code synthesized in the center of the first code; making quasi-bright cells in the cells of the formation range that are closer to light cells than dark cells as dark cells; and making quasi-dark cells that are closer to dark cells than light cells as light cells.

[0013] In these methods, the second code is smaller than the first code and is synthesized in the center of the first code. Therefore, the quasi-dark cells and quasi-bright cells are not formed near the outer edge of the information code. In this way, by avoiding the outer edge that is easily affected by light, even if the information code contains quasi-dark cells and quasi-bright cells, the failure of reading can be reduced.

[0014] In addition, the reference numbers in brackets in the claims are only an example of the corresponding relationship with the specific configuration in the embodiment described later, and do not limit the technical scope in any way. In addition, if the combination does not particularly cause obstacles, the combination of claims not explicitly stated in the claims can also be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing an information code according to one embodiment of the present disclosure.

[0016] Figure 2 This figure shows the overall picture when the traceability system is used together with the existing distribution management system.

[0017] Figure 3 This is a diagram for explaining the details of the synthesis area of ​​the synthesized concealment code.

[0018] Figure 4 This is a diagram for explaining the details of the magnification factor set for the concealment code.

[0019] Figure 5 It is magnified Figure 1 An enlarged view of area V of the information code.

[0020] Figure 6 This is a diagram for explaining the rules for synthesizing a public code and a private code.

[0021] Figure 7 This is a flowchart showing the details of the code generation process performed by the history management server.

[0022] Figure 8 This is a flowchart showing the details of the code reading process performed by a code scanner or the like.

[0023] Fig. 9 This is a diagram showing the details of image processing for extracting a concealment code from an information code.

[0024] Fig.10 This is a diagram for explaining the influence of light generated when reading a confidential code.

[0025] Fig.11 This is a diagram for explaining the details of the magnification factor set for the concealment code according to the first modification.

[0026] Fig.12 This is a detailed diagram showing the synthesis area set for the information code in variant example 2.

[0027] Fig.13 This is a diagram for explaining the details of the magnification factor set for the concealment code according to the second modification. DETAILED DESCRIPTION

[0028] Generated by synthesizing two QR codes Figure 1 The information code CQ2 of one embodiment of the present disclosure is shown. The two-dimensional code that forms the basis of the information code CQ2 is, for example, a QR code (registered trademark), etc., which records information through a two-dimensional arrangement of multiple cells Ce. The information code CQ2 is printed on a paper medium, etc., and is used in the form of a code printing medium such as a label, a sticker, and a tag. The information code CQ2 can also be displayed on a display device such as a display and electronic paper.

[0029] The information code CQ2 of this embodiment is generated by synthesizing the public code Cd1 and the concealed code Cd2. Figure 2 ) reads the information code CQ2, 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, by using the code scanner 23 described later (refer to Figure 2 ) etc., can read the confidentiality code Cd2. In this case, the information recorded in the confidentiality code Cd2 (hereinafter referred to as confidential information) is read.

[0030] exist Figure 2 The circulation management system 110 and the traceability system 120 shown both use the information code CQ2. The circulation management system 110 and the traceability system 120 are management systems for managing the supply chain SC constructed by many traders TR. The supply chain SC is a connection between traders for delivering industrial products, agricultural products, and aquatic products to end users. As an example, in the supply chain SC for delivering agricultural products to consumers, farmers TR1, agricultural cooperatives TR2 as purchasing facilities, transporters TR3, and retailers TR4 are included in the traders TR.

[0031] The circulation management system 110 collects transaction records of transaction items between traders TR using the public code Cd1. In other words, the public code Cd1 is a QR code used by the circulation management system 110. The circulation management system 110 is composed of an input terminal 11, a label printer 12, a code reader 13, and a system server 10. The input terminal 11, the label printer 12, and the code reader 13 are appropriately installed in the facilities of each trader TR. The input terminal 11, the label printer 12, and the code reader 13 are connected to the system server 10 installed in a data center or the like through a network.

[0032] The input terminal 11 is, for example, a personal computer or a tablet terminal. Basic information (hereinafter referred to as item information) of the transaction items supplied to the supply chain SC is input into the input terminal 11 in a prescribed format. For example, the item name, production location, production equipment, and producer are item information. The input terminal 11 sends the item information of the transaction items shipped from the trader TR to the system server 10.

[0033] The label printer 12 is an output device for printing the public code Cd1 on a paper medium. The label printer 12 can print in color or grayscale. The paper medium printed with the public code Cd1 is attached to the packaging or outer box of the shipped transaction item and circulated as an attachment to the transaction item.

[0034] 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 .

[0035] The system server 10 is a host node that can communicate with the input terminal 11, the label printer 12, and the code reader 13. The system server 10 registers the project information obtained from the input terminal 11 in the database. The system server 10 prepares public information associated with the project information and generates a public code Cd1 that records the public information. The system server 10 sends the image data of the generated public code Cd1 to the label printer 12, which is the source of the project information, as a process of issuing the public code Cd1. The issued public code Cd1 is circulated together with the transaction item. If it is read by the code reader 13 of another trader TR, the system server 10 accumulates the transaction record of the transaction item of the trader TR.

[0036] The traceability system 120 is used together with the circulation management system 110, and accumulates transaction records in the same manner as the circulation management system 110. In detail, the circulation management system 110 is equivalent to the old management system, and the traceability system 120 is equivalent to the new management system. The traceability system 120 does not actually make any changes to the existing circulation management system 110, but is used together with the circulation management system 110. In addition to the record generation function of accumulating transaction records, the traceability system 120 also has a record reference function of providing accumulated transaction records in a referenceable manner. In the traceability system 120, blockchain technology is used in the management of transaction records for the purpose of preventing tampering of transaction records.

[0037] The traceability system 120 collects transaction records using the information code CQ2 based on the public code Cd1 issued by the system server 10. The traceability system 120 is composed of a code output machine 22, a code scanner 23, and a history management server 20. In addition, the traceability system 120 uses the input terminal 11 and the label printer 12 of the circulation management system 110. The code output machine 22, the code scanner 23, and the input terminal 11 are connected to the history management server 20 set in the data center through a network.

[0038] The code output machine 22 is installed in the facility of the trader TR where the label printer 12 is installed. The code output machine 22 is installed in the form of inserting the communication line between the system server 10 and the label printer 12, and obtains the data of the public code Cd1 sent from the system server 10 to the label printer 12. The code output machine 22 sends the obtained data of the public code Cd1 to the history management server 20.

[0039] The code output machine 22 receives data of the information code CQ2 generated based on the sent public code Cd1 from the history management server 20. The information code CQ2 further records the confidential information used in the traceability system 120. The code output machine 22 sends the data of the information code CQ2 to the label printer 12 instead of the data of the public code Cd1. With the intervention of the code output machine 22, the label printer 12 does not recognize the change (replacement) of the acquired code data, but prints the information code CQ2 on the paper medium. As a result, the code printing medium printed with the information code CQ2 instead of the public code Cd1 is affixed to the transaction item and circulated together with the transaction item.

[0040] The code scanner 23 is a device for reading the information recorded in the information code CQ2 and the confidential information added to the information code CQ2 independently of the public information. The code scanner 23 is configured to scan the same object as the code reader 13, so it can also be physically integrated with the code reader 13. The code scanner 23 is composed of a photographing sensor in which CCD elements are arranged two-dimensionally, and a signal processing unit 41. The photographing sensor can read the information recorded in a plane with a higher resolution than the code reader 13. The photographing sensor outputs a photographed image (hereinafter referred to as a code photographed image) on which the information code CQ2 is reflected to the signal processing unit 41.

[0041] The signal processing unit 41 includes a storage unit for storing a code reading program and the like, and performs a code reading process described later based on the code reading program (see Figure 7) processor and RAM. The signal processing unit 41 decodes the read signal (code captured image) of the imaging sensor according to the prescribed rules through code reading processing, and obtains 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 leave a transaction record.

[0042] Alternatively, a smartphone 23s having a camera function may be used (see Fig.10 ) and tablet terminals as the code scanner 23. In such a method, a dedicated application (hereinafter referred to as a code reading application) equivalent to a code reading program is provided and installed on a smartphone 23s, etc. The code reading application reads not only the concealed code Cd2 but also the public code Cd1.

[0043] The history management server 20 is a host node that can communicate with the input terminal 11 in addition to the code output machine 22 and the code scanner 23. The history management server 20 is mainly composed of a computer having a processing unit 31, a RAM 32, a storage unit 33, an input / output interface, and a bus connecting them. The processing unit 31 is hardware for calculation processing combined with the RAM 32. The processing unit 31 performs various processes related to data management by accessing the RAM 32. The storage unit 33 stores a code generation program for causing the processing unit 31 to execute the code generation method disclosed in the present invention as one of the management programs related to data management.

[0044] The history management server 20 acquires the item information sent from the input terminal 11 to the system server 10. Based on the acquisition of the item information, the history management server 20 generates a blockchain associated with the transaction item, and is a blockchain for storing the item information and transaction records. If the history management server 20 acquires a notification of the fact that the information code CQ2 has been read from the code scanner 23 of each trader TR, the transaction record of the trader TR of the notification source is accumulated in the blockchain associated with the transaction item.

[0045] 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 trader TR of the notification source. In addition to the transaction records of this time, the new block also contains a hash value calculated based on the previous block. The hash value is generated using a hash function such as SHA-256. The hash value is data that maintains a specified number of bits (for example, 256 bits) and reflects the project information and transaction records.

[0046] The history management server 20 performs the code generation process described later (see Figure 6), generates 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. Thus, the hash value reflecting the item information and the transaction record is recorded in the information code CQ2 and can be circulated together with the transaction item.

[0047] In addition, in the traceability system 120, one information code CQ2 can continue to be used across multiple traders TR, or a new information code CQ2 can be issued for each trader TR. In the method of issuing a new information code CQ2 for each trader TR, based on the generation of transaction records of each trader TR, a latest hash value reflecting the transaction record is generated. The history management server 20 newly generates an information code CQ2 that records the latest hash value as confidential information, and provides the data of the new information code CQ2 to the label printer 12 of the facility of the trader TR who conducted the transaction. As a result, as the transaction of the item proceeds, the content (hash value) of the information code CQ2 is continuously updated to reflect the content of the transaction record so far. In addition, since the confidential information is content based on the hash value, the amount of confidential information data can be maintained constantly even as the transaction of the item develops in the supply chain SC.

[0048] The history management server 20 can further issue a traceability code QRt. The traceability code QRt is a two-dimensional code such as a QR code attached to the final product FP supplied through the supply chain SC. The traceability code QRt enables consumers who have obtained the final product FP to confirm the transaction record. As an example, the traceability code QRt records a hash value calculated based on the last block of the blockchain and an IP address or URL indicating the inquiry destination of the transaction record.

[0049] The consumer of the final product FP can browse the transaction record of the final product FP by using a user terminal 50 such as a smartphone or a tablet terminal, for example, and using a traceability confirmation application. Specifically, if the user terminal 50 reads the traceability code QRt attached to the final product FP, it sends a reference request for the transaction record together with the hash value to the history management server 20 that is the destination of the inquiry. If the history management server 20 receives the reference request, it extracts the item information and transaction record associated with the hash value and generates provision data. The history management server 20 sends the generated provision data to the user terminal 50 that is the request source of the reference request. The consumer of the final product FP can confirm the history of the transaction record by expanding the provision data received from the history management server 20 using the traceability confirmation application.

[0050] Next, based on Figure 1 as well as Figure 3 to Figure 6 The information code CQ2 is further described in detail.

[0051] As described above, the information code CQ2 is generated by synthesizing the public code Cd1 and the concealed code Cd2 (see Figure 1 ). The public code Cd1 and the hidden code Cd2 record information through the two-dimensional arrangement of white cells Cew and black cells Ceb respectively. The public code Cd1 and the hidden code Cd2 are two-dimensional codes with different numbers of cells (versions). The hidden 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 hidden code Cd2. Therefore, the number of cells in the public code Cd1 is greater than the number of cells in the hidden code Cd2. The information code CQ2 formed by overlapping the hidden code Cd2 on the public code Cd1 becomes a two-dimensional code with the same number of cells (version) as the public code Cd1.

[0052] The hidden code Cd2 is enlarged by an integer multiple of the public code Cd1 and then synthesized with the public code Cd1. Therefore, one cell Ce of the hidden code Cd2 is synthesized across multiple cells Ce of the public code Cd1. As an example, when the hidden code Cd2 is enlarged by two times, the enlarged one cell Ce overlaps with four (2×2) cells Ce of the public code Cd1. At this time, the four sides of the enlarged cell Ce overlap with the four boundaries that become the periphery without deviation. The hidden code Cd2 avoids the specific area SA of the public code Cd1 (refer to Figure 3 ), and overlapped at the center of the public code Cd1. As an example, at least the positioning pattern FiP and the format information area FiA of the public code Cd1 are the specific area SA.

[0053] The positioning pattern FiP is a pattern used to detect 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 the format information of the two-dimensional code, specifically, the information indicating the error correction level and the mask pattern. The format information area FiA is defined as an I-shape or an L-shape at the position adjacent to each positioning pattern FiP.

[0054] By avoiding the above-mentioned specific area SA, in the public code Cd1, the central area except for the eight cells or nine cells adjacent to the four outer edges becomes the composite area CA where the concealed code Cd2 can be configured. That is, the number of cells in the composite area CA is seventeen cells less in both the vertical and horizontal directions than the number of cells in the public code Cd1. The composite area CA becomes a configuration that further avoids the version information area ViA, the timing pattern TiP, and a part of the alignment pattern AlP in addition to the above-mentioned positioning pattern FiP and the format information area FiA. The version information area ViA is an area that records the information representing the version of the two-dimensional code. The version information area ViA is defined at a position adjacent to the two positioning patterns FiP that are configured diagonally.

[0055] The magnification ratio of the concealed code Cd2 is set so that the magnified concealed code Cd2 (hereinafter referred to as the magnified code Cde) is stored in the synthesis area CA. Therefore, the magnification ratio of the concealed code Cd2 is determined based on the versions of the public code Cd1 and the concealed code Cd2 to be synthesized (see Figure 4 As an example, when the version of the public code Cd1 is 17 (the number of cells is 85×85), the size of the composite area CA is 68×68. In this case, if the version of the concealed code Cd2 is 4 (the number of cells is 33×33), the magnification factor can be set to two times (refer to Figure 4 dotted line).

[0056] In addition to the white cell Cew and the black cell Ceb, the information code CQ2 also includes a bright color cell Cc1 (refer to Figure 1 as well as Figure 5 light gray range) and dark colored cell Cc2 (ref. Figure 1 as well as Figure 5 The bright color cell Cc1 and the dark color cell Cc2 are arranged only in the composite area CA. The information code CQ2 maintains both public information and private information through a two-dimensional arrangement of white cells Cew, black cells Ceb, bright color cells Cc1, and dark color cells Cc2. The combination of the white cells Cew and the black cells Ceb of the public code Cd1 and the private code Cd2 determines each cell Ce of the information code CQ2 (refer to Figure 6 ).

[0057] Specifically, the cell Ce at the position where both the public code Cd1 and the concealed code Cd2 are black cells Ceb is also black cell Ceb in the information code CQ2. Similarly, the cell Ce at the position where both the public code Cd1 and the concealed code Cd2 are white cells Cew is also white cell Cew in the information code CQ2.

[0058] On the other hand, the cell Ce at the position where the public code Cd1 is the black cell Ceb and the concealed code Cd2 is the white cell Cew becomes a dark color cell Cc2 (see Figure 6 In addition, the cell Ce at the position where the public code Cd1 is a white cell Cew and the concealed code Cd2 is a black cell Ceb becomes a bright color cell Cc1 (refer to Figure 6 The dark color cell Cc2 is a color having a brightness close to that of the black cell Ceb compared to the white cell Cew, and is a color cell Ce having a brightness lower than that of the light color cell Cc1. For example, red, blue, green, etc. can be used as the color of the dark color cell Cc2. The light color cell Cc1 is a color having a brightness close to that of the white cell Cew compared to the black cell Ceb, and is a color cell Ce having a brightness higher than that of the dark color cell Cc2. For example, yellow, etc. can be used as the color of the light color cell Cc1.

[0059] In the information code CQ2, dark gray cells Cg2 and light gray cells Cg1 can be used instead of the above-mentioned dark color cells Cc2 and light color cells Cc1. In the case where the label printer 12 is not capable of color output and can output in grayscale, dark gray cells Cg2 and light gray cells Cg1 are used. The dark gray cell Cg2 is an achromatic cell that is closer to the black cell Ceb than the white cell Cew, and is a cell Ce of an intermediate color with a lower brightness than the light gray cell Cg1. For example, a dark gray color with a brightness of about 25% of the white cell Cew can be used as the color of the dark gray cell Cg2. In addition, the light gray cell Cg1 is an achromatic cell that is closer to the white cell Cew than the black cell Ceb, and is a cell Ce of an intermediate color with a higher brightness than the dark gray cell Cg2. For example, a light gray color with a brightness of about 75% of the white cell Cew can be used as the color of the light gray cell Cg1.

[0060] Here, the code reader 13 (see Figure 2 ) When reading the information code CQ2, the brightness of each cell Ce is detected, in other words, the light reflectivity of each cell Ce is checked. Therefore, the code reader 13 distinguishes the bright color cell Cc1 and the bright gray cell Cg1 as white cells Cew, and distinguishes the dark color cell Cc2 and the dark gray cell Cg2 as black cells Ceb. As a result, the code reader 13 can recognize the information code CQ2 as a two-dimensional code substantially the same as the public code Cd1, and read the public information.

[0061] Next, based on Figure 7 , and refer to Figure 1 , Figure 2 , Figures 4 to 6 The code generation process (code generation method) for generating the information code CQ2 described so far will be described in detail.

[0062] In the code generation process, first, a public code Cd1 and a private code Cd2 are prepared. Specifically, in S11, the history management server 20 obtains the public code Cd1 by receiving it from the code output device 22. Next, in S12, the history management server 20 obtains a hash value reflecting the item information and the transaction record, and prepares private information including the hash value as the main body.

[0063] In S13, the history management server 20 determines the version and magnification of the confidential code Cd2 based on the version of the public code Cd1 obtained in S11. As an example, when the version of the public code Cd1 is 17, the version of the confidential code Cd2 is 4 or less. The history management server 20 determines the version and error correction level of the confidential code Cd2 so that the data amount (number of bits) of the confidential information obtained in S12 can be recorded. Then, the signal processing unit 41 further determines the maximum magnification that can accommodate the determined confidential code Cd2 in the synthesis area CA.

[0064] In S14, the history management server 20 generates a confidentiality code Cd2 of the version and error correction level determined in S13. In S15, the history management server 20 amplifies the confidentiality code Cd2 at the amplification factor determined in S13 to generate an amplified code Cde.

[0065] In S16, the history management server 20 combines the enlarged code Cde generated in S15 with the combined area CA of the public code Cd1 acquired in S11. As described above, in the public code Cd1, the black cell Ceb overlapping the white cell Cew of the enlarged code Cde is converted into a dark color cell Cc2 or a dark gray cell Cg2 (see Figure 6 ). In addition, in the public code Cd1, the white cell Cew overlapping the black cell Ceb of the enlarged code Cde is converted into a bright color cell Cc1 or a bright gray cell Cg1. As a result, an information code CQ2 is generated by two-dimensionally arranging the white cell Cew, the black cell Ceb, the bright color cell Cc1, and the dark color cell Cc2. The information code CQ2 generated in this way is issued to the trader TR in S17.

[0066] Next, based on Figure 8 as well as Fig. 9 , and refer to Figure 1 to Figure 3The code reading process (code reading method) of reading the confidentiality code Cd2 from the information code CQ2 will be described in detail.

[0067] In S31 of the code reading process, the signal processing unit 41 grasps the position and posture of the information code CQ2 reflected in the code shooting image based on the detection of the positioning pattern FiP. Based on the information of the position and posture of the information code CQ2, the signal processing unit 41 applies pre-processing such as keystone correction and color correction to the range where the information code CQ2 is reflected in S32, and prepares a processed image suitable for code reading (hereinafter referred to as the corrected image Pc0). 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 grayscale value of the entire image is adjusted so that the grayscale values ​​of the white cell Cew and the black cell Ceb of the information code CQ2 are approximately the same value.

[0068] In S33, the signal processing unit 41 determines the composite area CA in which the concealment code Cd2 is composited with the information code CQ2 reflected in the corrected image Pc0, and cuts out the determined composite area CA from the information code CQ2. In other words, in S33, the central area in which the light color cell Cc1 and the dark color cell Cc2 are arranged is determined and cut out.

[0069] In order to determine the composite area CA, the signal processing unit 41 first generates a first conversion image Pc1 (see FIG. 1 ) by converting the black cell Ceb of the information code CQ2 into the same white as the white cell Cew. Fig. 9 ). Next, the signal processing unit 41 generates a second conversion image Pc2 by converting the bright color cells Cc1 and the dark color cells Cc2 of the first conversion image Pc1 into the same black as the black cell Ceb. Furthermore, the signal processing unit 41 generates an inverted image Pc3 by inverting the brightness and darkness (white and black) of the colors in the second conversion image Pc2. The signal processing unit 41 determines the composite area CA based on the range of the bright color (white) in the inverted image Pc3. In detail, the signal processing unit 41 infers the coordinates of a pair of corners that are diagonally opposite to each other within the white range of the inverted image Pc3 by marking the inverted image Pc3. The signal processing unit 41 obtains a pair of coordinates as coordinates representing the formation range of the composite area CA. Based on the obtained coordinates, the signal processing unit 41 cuts out a cut-out image Pc4 containing the concealment code Cd2 from the composite area CA of the corrected image Pc0.

[0070] In S34, the signal processing unit 41 extracts the concealment code Cd2 from the cut-out image Pc4 by applying the color conversion process. Specifically, the signal processing unit 41 generates an extracted image Pc5 from which the concealment code Cd2 is extracted by black-and-white conversion of the light color cell Cc1 in the cell Ce of the composite area CA to the black cell Ceb and the dark color cell Cc2 to the white cell Cew. Furthermore, the signal processing unit 41 removes the noise and worm-eye pattern generated in the extracted image Pc5 by dilating and contracting the black range in the extracted image Pc5. By applying such a correction process to the extracted image Pc5, the signal processing unit 41 generates a restored image Pc6 from which the concealment code Cd2 is restored.

[0071] The signal processing unit 41 reads the restored image Pc6 as the concealed code Cd2 and reads the concealed information in S35, thereby completing the code reading process. At this time, in the restored image Pc6, one cell Ce of the concealed code Cd2 is equivalent to the size of multiple cells Ce of the public code Cd1. Therefore, the signal processing unit 41 reads the concealed code Cd2 as one cell Ce in the public code Cd1. Therefore, it becomes easy to read the concealed information from the restored image Pc6.

[0072] In addition, the code reading process may be performed by the history management server 20. In such a manner, the captured code image or the corrected image Pc0 is transmitted from the code scanner 23 to the history management server 20. The history management server 20 performs a process of reading the concealment code Cd2 from the captured code image or the corrected image Pc0 obtained by receiving. In addition, in the case where the light gray cell Cg1 and the dark gray cell Cg2 are used instead of the light color cell Cc1 and the dark color cell Cc2, the concealment code Cd2 can also be restored by the above process.

[0073] In the present embodiment described so far, since the concealed code Cd2 is enlarged relative to the public code Cd1, the size of the cell Ce of the concealed code Cd2 is larger than the size of the cell Ce of the public code Cd1. Therefore, even for the information code CQ2 including the dark color cell Cc2 and the light color cell Cc1, the failure of code reading can be reduced.

[0074] In detail, for a two-dimensional code, the smaller the size of a cell Ce is, the more difficult it is to read. In particular, if the information code CQ2 including the bright color cell Cc1 and the dark color cell Cc2 becomes thinner, the recognition performance is further degraded. For such a problem, in the present embodiment, the hidden code Cd2, which is a smaller version than the public code Cd1, is enlarged relative to the public code Cd1 and then synthesized with the public code Cd1. In this way, by enlarging the hidden code Cd2 during synthesis, the size of a cell Ce can be ensured, so even if the bright color cell Cc1 and the dark color cell Cc2 are included, the degradation of the recognizability can be suppressed.

[0075] In addition, in this embodiment, the confidential information recorded in the confidential code Cd2 is mainly composed of hash values. Therefore, the amount of information that needs to be recorded as confidential information can be suppressed, so the version of the confidential code Cd2 can be reduced. As described above, the method of improving the recognizability by amplifying the confidential code Cd2 is suitable for the traceability system 120 that records the hash value as confidential information.

[0076] In addition, in the present embodiment, the concealed code Cd2 is amplified by an integer multiple relative to the public code Cd1 and is synthesized with the public code Cd1. Therefore, it is possible to avoid the situation where a plurality of cells Ce of the concealed code Cd2 are synthesized in one cell Ce of the public code Cd1. Based on the above, the recognizability of the public code Cd1 can be ensured, so the failure of reading the public code Cd1 can be reduced.

[0077] Furthermore, in this embodiment, the concealed code Cd2 is smaller in size than the public code Cd1 and is synthesized in the center of the public code Cd1. Therefore, dark color cells Cc2 and bright color cells Cc1 are not formed near the outer edge of the information code CQ2. In this way, by avoiding the outer edge that is easily affected by light, even if the information code CQ2 includes dark color cells Cc2 and bright color cells Cc1, it is possible to reduce reading failures.

[0078] In detail, Fig.10 As shown, for example, when the code reading application of the smartphone 23s is used to read the information code CQ2 printed on the label, light enters the label side from the periphery of the smartphone 23s, so the light influence occurs near the outer edge of the information code CQ2. As a result, a phenomenon such as white spots appearing around the public code Cd1 read from the information code CQ2 (see Fig.10ellipse range). When the influence of such light reaches the bright color cell Cc1, it becomes difficult to distinguish the bright color cell Cc1 from the white cell Cew, so the bright color cell Cc1 that should be converted into the black cell Ceb is easily misidentified as the white cell Cew due to the influence of light. As a result, it becomes difficult to return the processing of each color cell Cc1 and Cc2 to the black cell Ceb and the white cell Cew. In addition, even when the code scanner 23 is used, the same problem may occur.

[0079] However, in this embodiment, the size of the concealed code Cd2 (enlarged code Cde) is set to be larger than the public code Cd1, and the concealed code Cd2 is arranged in the center of the public code Cd1. Therefore, the influence of light is not easy to affect the color cells Cc1 and Cc2. As a result, the processing of returning the color cells Cc1 and Cc2 to the black cell Ceb and the white cell Cew can be reliably implemented, so the failure of reading the concealed code Cd2 can be reduced.

[0080] Furthermore, if the version of the information code CQ2 increases, the distance between the code scanner 23 or the smart phone 23s and the information code CQ2 tends to become farther in order to read the entire information code CQ2. As a result, light is more likely to enter the outer edge of the information code CQ2. However, according to the central arrangement of the hidden code Cd2, the influence of light on each color cell Cc1 and Cc2 can be suppressed. As described above, the larger the version of the public code Cd1, the more effective it is to reduce the failure of code reading by arranging the hidden code Cd2 in the center of the public code Cd1.

[0081] In addition, in the present embodiment, the concealed code Cd2 avoids the specific area SA of the public code Cd1 and is synthesized with the public code Cd1. Specifically, the positioning pattern FiP and the format information area FiA are the specific area SA, and the bright color cell Cc1 and the dark color cell Cc2 are not arranged in the positioning pattern FiP and the format information area FiA. Thus, the degradation of the recognition of the public code Cd1 can be suppressed, so the failure of reading the public code Cd1 can be reduced.

[0082] In addition, in the present embodiment, in the step of determining the composite area CA, a first conversion image Pc1 is generated by converting the black cell Ceb of the information code CQ2 into the same color as the white cell Cew. Furthermore, a second conversion image Pc2 is generated by converting each color cell Cc1 and Cc2 of the first conversion image Pc1 into the same color as the black cell Ceb, and an inverted image Pc3 is generated by inverting the light and dark of the color in the second conversion image Pc2. Furthermore, the composite area CA is determined based on the range of the bright color in the inverted image Pc3. As described above, by performing the image processing of black and white inversion after turning each color cell Cc1 and Cc2 black, the processing of determining the formation range of each color cell Cc1 and Cc2 can be accelerated. As a result, the hidden information can be quickly read from the information code CQ2.

[0083] In the above embodiment, the signal processing unit 41 is equivalent to the "processing unit" for implementing the code reading method, the public code Cd1 is equivalent to the "first code", and the concealed code Cd2 is equivalent to the "second code". In addition, the white cell Cew is equivalent to the "light cell", the black cell Ceb is equivalent to the "dark cell", the light color cell Cc1 or the light gray cell Cg1 is equivalent to the "quasi-light cell", and the dark color cell Cc2 or the dark gray cell Cg2 is equivalent to the "quasi-dark cell". And the composite area CA is equivalent to the "formation range".

[0084] Technical ideas that can be further grasped from the embodiments described so far are described below as Supplementary Notes 1 to 6.

[0085] (Note 1)

[0086] A code generation method comprises the following steps in a process performed by at least one processing unit (31):

[0087] preparing a first code (Cd1) and a second code (Cd2) for recording information by two-dimensionally arranging a plurality of cells (Ce) (S11 to S14); and

[0088] Generate an information code (CQ2) synthesized from the first code and the second code (S15, S16),

[0089] In the step of synthesizing the first code and the second code,

[0090] By enlarging the second code relative to the first code, one cell of the second code is synthesized across a plurality of cells of the first code,

[0091] The cells at the positions where the first code and the second code are both bright cells (Cew) are bright cells,

[0092] The cell at the position where both the first code and the second code are dark cells (Ceb) is the dark cell,

[0093] The cells at the positions where the first code is the light color cell and the second code is the dark color cell are quasi-light color cells (Cc1, Cg1) whose colors are closer to the light color cells than the dark color cells.

[0094] The cells at the positions where the first code is the dark cell and the second code is the light cell are quasi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell.

[0095] (Note 2)

[0096] A code generation method comprises the following steps in a process performed by at least one processing unit (31):

[0097] preparing a first code (Cd1) and a second code (Cd2) for recording information by two-dimensionally arranging a plurality of cells (Ce) (S11 to S14); and

[0098] Generate an information code (CQ2) synthesized from the first code and the second code (S15, S16),

[0099] In the step of synthesizing the first code and the second code,

[0100] The second code having a smaller size than the first code is synthesized at the center of the first code.

[0101] The cells at the positions where the first code and the second code are both bright cells (Cew) are bright cells,

[0102] The cell at the position where both the first code and the second code are dark cells (Ceb) is the dark cell,

[0103] The cells at the positions where the first code is the light color cell and the second code is the dark color cell are quasi-light color cells (Cc1, Cg1) whose colors are closer to the light color cells than the dark color cells.

[0104] The cells at the positions where the first code is the dark cell and the second code is the light cell are quasi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell.

[0105] (Note 3)

[0106] A code generating device is a code generating device for generating an information code (CQ2) synthesized by a first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional arrangement of a plurality of cells (Ce), comprising:

[0107] A code preparation unit (S11-S14), preparing the first code and the second code; and

[0108] A code synthesis unit (S15, S16) generates the information code synthesized from the first code and the second code,

[0109] The code synthesis unit performs:

[0110] By enlarging the second code relative to the first code, one cell of the second code is synthesized across a plurality of cells of the first code;

[0111] The cells at the positions where the first code and the second code are both bright cells (Cew) are the bright cells;

[0112] The cell at the position where both the first code and the second code are dark cells (Ceb) is the dark cell;

[0113] The cells at the positions where the first code is the light color cell and the second code is the dark color cell are quasi-light color cells (Cc1, Cg1) whose color is closer to the light color cell than the dark color cell; and

[0114] The cells at the positions where the first code is the dark cell and the second code is the light cell are quasi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell.

[0115] (Note 4)

[0116] A code generating device is a code generating device for generating an information code (CQ2) synthesized by a first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional arrangement of a plurality of cells (Ce), comprising:

[0117] A code preparation unit (S11-S14), preparing the first code and the second code; and

[0118] A code synthesis unit (S16) generates the information code synthesized from the first code and the second code.

[0119] The code synthesis unit performs:

[0120] Synthesize the second code smaller than the first code at the center of the first code;

[0121] The cells at the positions where the first code and the second code are both bright cells (Cew) are the bright cells;

[0122] The cell at the position where both the first code and the second code are dark cells (Ceb) is the dark cell;

[0123] The cells at the positions where the first code is the light color cell and the second code is the dark color cell are quasi-light color cells (Cc1, Cg1) whose color is closer to the light color cell than the dark color cell; and

[0124] The cells at the positions where the first code is the dark cell and the second code is the light cell are quasi-dark cells (Cc2, Cg2) whose color is closer to the dark cell than the light cell.

[0125] (Note 5)

[0126] A code reading device is a code reading device for reading the second code from an information code (CQ2) synthesized by a first code (Cd1) recording information by a two-dimensional arrangement of a plurality of cells (Ce) and a second code (Cd2), comprising:

[0127] An image acquisition unit (S31) acquires a code-captured image on which the information code is projected; and

[0128] The image conversion unit (S34, S35) makes the quasi-bright color cells (Cc1, Cg1) of the above-mentioned cells of the above-mentioned information code, which are closer to the light color cells (Cew) than the dark color cells (Ceb), dark color cells, and makes the quasi-dark color cells (Cc2, Cg2) of the above-mentioned cells, which are closer to the above-mentioned dark color cells than the above-mentioned light color cells, light color cells,

[0129] The image conversion unit reads the second code by treating a plurality of cells in the first code as one cell.

[0130] (Note 6)

[0131] A code reading device is a code reading device for reading the second code from an information code (CQ2) synthesized by a first code (Cd1) recording information by a two-dimensional arrangement of a plurality of cells (Ce) and a second code (Cd2), comprising:

[0132] An image acquisition unit (S31) acquires a code-captured image on which the information code is projected; and

[0133] The image conversion unit (S33, S34) determines a formation range (CA) of the second code synthesized in the center of the first code, and makes quasi-bright cells (Cc1, Cg1) of a color closer to the light cell (Cew) than the dark cell (Ceb) among the cells of the formation range dark cells, and makes quasi-dark cells (Cc2, Cg2) of a color closer to the dark cell than the light cell as light cells.

[0134] In addition, in the above-mentioned 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".

[0135] (Other Embodiments)

[0136] As mentioned above, although one embodiment of the present disclosure has been described, the present disclosure is not limited to the above embodiment and can be applied to various embodiments and combinations within the scope not departing from the gist of the present disclosure.

[0137] In the first variant 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 variant, the specific area SA that should be avoided from synthesis is not set. As a result, a larger magnification ratio can be set for the concealed code Cd2 than in the above embodiment. As an example, the enlarged code Cde obtained by magnifying the concealed code Cd2 of version 4 by two times can be synthesized with the public code Cd1 of version 13 (see Fig.11 As a result, in the first modification, the recognizability of the concealment code Cd2 can be further improved.

[0138] In the second variation of the above embodiment, Fig.12 As shown, the synthesis area CA is configured to be offset to an angle among the four corners of the information code CQ2 where the positioning pattern FiP does not exist. In variant example 2, compared with the above-mentioned embodiment in which the synthesis area CA is set in the center of the information code CQ2, the area of ​​the synthesis area CA can be expanded. The number of cells in the synthesis area CA is nine cells and eight cells less in the vertical and horizontal directions than the number of cells of the public code Cd1. For example, in the case where the version of the public code Cd1 is 15 (the number of cells is 77×77), the size of the synthesis area CA is 68×69. In this case, it is possible to synthesize an enlarged code Cde (refer to Fig.13 dotted line).

[0139] In the above-mentioned Modifications 1 and 2, the same effect as that of the above-mentioned embodiment is achieved, and the failure of code reading can be reduced by amplifying the concealment code Cd2.

[0140] In the third variation of the above embodiment, the process of enlarging the concealed code Cd2 is omitted. The concealed code Cd2 is synthesized in the synthesized area CA in the center of the public code Cd1 so as to avoid the specific area SA. In the third variation above, since the bright color cell Cc1 and the dark color cell Cc2 are not arranged near the outer edge of the information code CQ2, the reduction in recognition due to the influence of light can also be avoided.

[0141] In the modification 4 of the above embodiment, the method of determining the composite area CA in the code reading process is different from that in the above embodiment. The signal processing unit 41 of the modification 4 starts searching for the bright color cell Cc1 and the dark color cell Cc2 from a pair of diagonally located corners (for example, the upper left corner and the lower right corner) in the information code CQ2. The signal processing unit 41 uses the positions of the detected bright color cell Cc1 and the dark color cell Cc2 as the coordinates representing the formation range of the composite area CA, and implements the cutting out of the cut-out image Pc4. By such a method, the coordinates of a pair of corners can also be inferred.

[0142] In variation 5 of the above embodiment, a magnification factor that is not an integer is set (for example, 1.5 times, etc.). As long as the reading of the public code Cd1 by the code reader 13 used in the circulation management system 110 does not hinder, the boundary of the cell Ce of the hidden code Cd2 can also be located in a cell Ce of the public code Cd1. In addition, in the above embodiment, the hidden code Cd2 is synthesized so that the boundary of the cell Ce of the hidden code Cd2 (magnified code Cde) overlaps with the boundary of the cell Ce of the public code Cd1. However, as long as the code can be read, the boundary of the cell Ce of the hidden code Cd2 can also be offset relative to the boundary of the cell Ce of the public code Cd1.

[0143] In the above embodiment, the light color forming the white cell Cew may not be strictly white. For example, the background color of the label printed with the information code CQ2 (for example, very light gray or ivory) may be equivalent to the light color. Similarly, the dark color forming the black cell Ceb may not be strictly black. For example, the color of the ink used in the label printer 12 (for example, dark blue or dark green) may be equivalent to the dark color.

[0144] The public code Cd1 and the concealed code Cd2 are not limited to QR codes. Two-dimensional codes different from QR codes can be used as the first code and the second code and combined into an information code. Furthermore, when QR codes are used as the codes, the error correction capabilities (error correction levels) can also be different from each other.

[0145] The information code CQ2 disclosed herein may also 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, which are the basis of the information code, is not limited to the above-mentioned public information and confidential information, and may be appropriately changed according to the purpose of the information code.

[0146] In the above embodiment, the traceability code QRt is issued separately from the information code CQ2 used in the supply chain SC and attached to the final product FP. However, the information code CQ2 can also be used as the traceability code QRt. In this case, the traceability confirmation application implements the above-mentioned code reading process and provides the user terminal 50 with the function of reading the hidden code Cd2. In addition, the final product FP supplied through the supply chain SC can be appropriately changed. For example, various items such as automobiles, batteries, semiconductors, fresh food, aquatic products, food, flowers, pharmaceuticals, and chemicals can be managed through the traceability system 120.

[0147] The hash function used in the history management server 20 is a cryptographic hash function, which has the characteristics that the same hash value will not be output according to different inputs, and the input cannot be inferred 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 can be appropriately used according to the output length (number of bits) that can be recorded in the hidden code Cd2 as hidden information. In addition, the code generation process implemented by the history management server 20 can also be implemented by the code output machine 22 that becomes the edge side. In such a method, the code output machine 22 is equivalent to a "code generation device".

[0148] In the above-mentioned embodiment, each function provided by the history management server and the code scanner etc. can also be provided by software and hardware executing the software, only by software, only by hardware, or by a combination of them. In the case where such functions are provided by an electronic circuit as hardware, each function can also be provided by a digital circuit or an analog circuit including a large number of logic circuits.

[0149] The processing unit (signal processing unit) of the above embodiment can be configured to include at least one CPU (Central Processing Unit) and GPU (Graphics Processing Unit) and other computing cores. In addition, the processing unit can be configured to further include FPGA (Field-Programmable Gate Array), NPU (Neural Network Processing Unit) and other IP cores with dedicated functions.

[0150] The form of the storage medium (non-transitory tangible storage medium) used as each storage unit of the above-mentioned embodiment and storing each program related to the code generation and code reading of the present disclosure can be appropriately changed. For example, the storage medium is not limited to the configuration provided on the circuit substrate, and can be configured to be provided in the form of a memory card, etc., and inserted into the socket portion, and electrically connected to the bus of the computer. In addition, the storage medium can also be an optical disk and a hard disk drive, etc., which serve as the basis for copying the program to the computer.

[0151] The control unit and method described in the present disclosure may also be implemented by a dedicated computer that is composed of a processor that is programmed to execute one or more functions embodied by a computer program. Alternatively, the device and method described in the present disclosure may also be implemented by a dedicated hardware logic circuit. Alternatively, the device and method described in the present disclosure may also be implemented by one or more dedicated computers that are composed of a processor that executes a computer program and one or more hardware logic circuits. In addition, the computer program may also be stored as an instruction executed by a computer in a non-migratable tangible recording medium that can be read by a computer.

Claims

1. An information code, which is a combination of a first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional arrangement of a plurality of cells (Ce), wherein: Include: bright cells (Cew); dark cells (Ceb); The quasi-bright color cell (Cc1, Cg1) is a color closer to the above-mentioned bright color cell than the above-mentioned dark color cell, and is distinguished in the same manner as the above-mentioned bright color cell in reading the above-mentioned first code, and is distinguished as the above-mentioned dark color cell in reading the above-mentioned second code; as well as The quasi-dark cells (Cc2, Cg2) are closer in color to the dark cells than to the light cells, and are identified as the dark cells in the reading of the first code, and are identified as the light cells in the reading of the second code. The second code is enlarged relative to the first code, and one cell of the second code is synthesized across a plurality of cells of the first code.

2. The information code according to claim 1, wherein: The second code is amplified by an integer multiple of the first code and is synthesized with the first code.

3. The information code according to claim 1, wherein: The second code has a smaller size than the first code and is synthesized at the center of the first code.

4. An information code, which is a combination of a first code (Cd1) and a second code (Cd2) for recording information by a two-dimensional arrangement of a plurality of cells (Ce), wherein: Include: bright cells (Cew); dark cells (Ceb); The quasi-bright color cell (Cc1, Cg1) is a color closer to the above-mentioned bright color cell than the above-mentioned dark color cell, and is distinguished in the same manner as the above-mentioned bright color cell in reading the above-mentioned first code, and is distinguished as the above-mentioned dark color cell in reading the above-mentioned second code; as well as The quasi-dark cells (Cc2, Cg2) are closer in color to the dark cells than to the light cells, and are identified as the dark cells in the reading of the first code, and are identified as the light cells in the reading of the second code. The second code has a smaller size than the first code and is synthesized 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 the specific area (SA) of the first code.

6. A code reading method, comprising: reading the second code from an information code (CQ2) synthesized from a first code (Cd1) and a second code (Cd2) recording information in a two-dimensional arrangement of a plurality of cells (Ce), wherein: The processing performed by at least one processing unit (41) includes the following steps: The quasi-bright cells (Cc1, Cg1) whose colors are closer to the bright cells (Cew) than the dark cells (Ceb) are made the dark cells; The quasi-dark cells (Cc2, Cg2) whose colors are closer to the dark cells than the light cells are made the light cells; and The second code is read by treating the plurality of cells in the first code as one cell.

7. A code reading method, comprising: reading the second code from an information code (CQ2) synthesized from a first code (Cd1) and a second code (Cd2) recording information in a two-dimensional arrangement of a plurality of cells (Ce), wherein: The processing performed by at least one processing unit (41) includes the following steps: determining a formation range (CA) of the second code synthesized at the center of the first code; Among the cells in the formation range, quasi-bright cells (Cc1, Cg1) whose colors are closer to the bright cells (Cew) than the dark cells (Ceb) are made the dark cells; as well as The quasi-dark color cells (Cc2, Cg2) whose colors are closer to the dark color cells than the light color cells are made to be the light color cells.

8. The code reading method according to claim 7, wherein: In the step of determining the above formation range: generating a first conversion image (Pc1) by converting the dark cells of the information code into the same color as the light cells; generating a second conversion image (Pc2) by converting the quasi-bright color cells and the quasi-dark color cells of the first conversion image into the same color as the dark color cells; generating an inverted image (Pc3) in which the brightness of the colors in the second conversion image is inverted; and The formation range is determined based on the range of the bright color in the reverse image.

Images