JP2018082285A - Information processing apparatus, information processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a change of an embedding method of a digital watermark, in a state where the digital watermark is readable.SOLUTION: An information processing apparatus for embedding additional information in a print image by multiple embedding methods includes a first additional information acquisition unit for acquiring additional information to be embedded in the print image, a first embedding method acquisition unit for acquiring the embedding method applied when embedding the additional information in the print image, out of the multiple embedding methods, an execution unit for embedding the additional information, acquired by the first additional information acquisition unit, in he print image by applying the embedding method acquired by first embedding method acquisition unit, and a registration unit for registering the embedding method applied to embedding processing by the embedding execution unit in association with the print image being the embedding processing object .SELECTED DRAWING: Figure 5

Description

  The present invention relates to an information processing apparatus, an information processing method, and a program.

  Electronic watermarking is known as a technique for embedding additional information in a printed material. In the conventional digital watermark technology, the embedded position of the digital watermark is set in advance, and is shared between the printing apparatus that prints the digital watermark and the reading apparatus that reads the digital watermark. The reading device was able to acquire additional information included in the digital watermark by reading the digital watermark embedded by a preset embedding method.

  However, in the above-mentioned conventional digital watermark technology, since the digital watermark is embedded in any printed matter by the same embedding method, the digital watermark embedding method (for example, the embedding position) can be grasped by a third party, and the digital watermark is added. There was a risk of information being stolen or altered by a third party.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to change the method for embedding a digital watermark while the digital watermark can be read.

  An information processing apparatus according to an embodiment is an information processing apparatus that embeds additional information in a print image by a plurality of embedding methods, and includes a first additional information acquisition unit that acquires additional information embedded in a print image, Among the embedding methods, a first embedding method acquisition unit that acquires the embedding method applied when embedding additional information in a print image, and the embedding method acquired by the first embedding method acquisition unit are applied. Then, an embedding execution unit for embedding the additional information acquired by the first additional information acquisition unit in a print image, the embedding method applied to the embedding process by the embedding execution unit, and the target of the embedding process A registration unit that registers the print image in association with each other.

  According to each embodiment of the present invention, it is possible to change the digital watermark embedding method while the digital watermark can be read.

The figure which shows an example of a structure of an information processing system. 1 is a diagram illustrating an example of a hardware configuration of an image forming apparatus. FIG. 3 is a diagram illustrating an example of a software group included in the image forming apparatus. The figure which shows an example of the hardware constitutions of a server. 2 is a diagram illustrating an example of a functional configuration of an image forming apparatus. FIG. The figure which shows an example of an internal structure of a digital watermark control part. The sequence diagram which shows an example of a printing process. The flowchart which shows an example of the production | generation process of embedding information. The figure which shows the specific example of the production | generation process of embedding information. 10 is a flowchart illustrating an example of a digital watermark generation process. The figure which shows the specific example of the production | generation process of a digital watermark. 5 is a flowchart illustrating an example of an identifier image generation process. The figure which shows the specific example of the production | generation process of an identifier image. The figure which shows an example of the identifier memorize | stored in the server, and embedding information. The sequence diagram which shows an example of a reading process. The flowchart which shows an example of the acquisition process of an identifier. 10 is a flowchart illustrating an example of an electronic watermark information acquisition process. The sequence diagram which shows an example of the addition process of an option. The figure which shows an example of the screen transition of the operation panel in an addition process. The sequence diagram which shows an example of the deletion process of an option. The figure which shows an example of the screen transition of the operation panel in a deletion process. The sequence diagram which shows an example of the change process of an option. The figure which shows an example of the screen transition of the operation panel in a change process. The figure which shows an example of an overlap area | region. 10 is a flowchart illustrating an example of a digital watermark generation process. The figure which shows the specific example of the production | generation process of a digital watermark. 10 is a flowchart illustrating an example of an electronic watermark acquisition process.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, regarding the description of the specification and the drawings according to each embodiment, constituent elements having substantially the same functional configuration are denoted by the same reference numerals and overlapping description is omitted.

(First embodiment)
An information processing system (hereinafter referred to as “system”) according to the first embodiment will be described with reference to FIGS. First, the system configuration will be described. FIG. 1 is a diagram illustrating an example of a system configuration. The system shown in FIG. 1 includes image forming apparatuses 1 a and 1 b, a server 2, a user terminal 3, and a network 4.

  The image forming apparatuses 1a and 1b are examples of information processing apparatuses, and are apparatuses that include at least one of a printing function and a scanner function. The image forming apparatuses 1a and 1b are, for example, a printing apparatus, a reading apparatus, and an MFP (Multi-Functional Peripheral). In the example of FIG. 1, the system includes two image forming apparatuses 1, but may include one or three or more image forming apparatuses 1. Hereinafter, when the image forming apparatuses included in the system are not distinguished, they are referred to as image forming apparatuses 1.

  The server 2 is an example of an information processing apparatus and is a server computer. The server 2 stores the embedded information transmitted by the image forming apparatus 1 and the identifier in association with each other. Details of the embedded information and the identifier will be described later.

  The user terminal 3 is a client computer used by a system user. The user terminal 3 is, for example, a PC (Personal Computer), a tablet terminal, a smartphone, or a mobile phone. The user can transmit a print image to be printed on the print medium from the user terminal 3 to the image forming apparatus 1. In addition, the user can transmit a print instruction or a read instruction from the user terminal 3 to the image forming apparatus 1. In the example of FIG. 1, the system includes one user terminal 3, but may include two or more user terminals 3.

  The network 4 is configured by a LAN (Local Area Network) or the Internet, and connects the image forming apparatus 1, the server 2, and the PC 3 so that they can communicate with each other by wire or wirelessly.

  Next, the hardware configuration of the image forming apparatus 1, the server 2, and the user terminal 3 will be described. However, since the hardware configuration of the user terminal 3 is the same as that of the server 2, description thereof is omitted.

  FIG. 2 is a diagram illustrating an example of a hardware configuration of the image forming apparatus 1. 2 is an MFP, and includes a controller 11, an operation panel 12, an FCU (Fax Control Unit) 13, a USB (Universal Serial Bus) device 14, an MLB 15, and an engine 16. . Although not shown, the image forming apparatus 1 includes a paper conveyance device, an imaging device, a printing device, a reading device, and the like.

  The controller 11 includes a CPU (Central Processing Unit) 111, a system memory 112, an ASIC (Application Specific Integrated Circuit) 113, and an HDD (Hard Disk Drive) 114. The controller 11 includes a TPM (Trusted Platform Module) chip 115, a PHY (Physical Layer) chip 116, and a data transfer bus 117.

  The CPU 111, the system memory 112, the HDD 114, and the PHY chip 116 are connected to the ASIC 113 via the data transfer bus 117. In the example of FIG. 2, the TPM chip 115 is mounted on the ASIC 113, but may be an independent LSI.

  The CPU 111 controls each component by executing a program to realize the functions (printing function, scanner function, etc.) of the image forming apparatus 1. The system memory 112 provides a work area for the CPU 111. The system memory 112 is a RAM (Random Access Memory), an SRAM (Static RAM), a DRAM (Dynamic RAM), or the like. The HDD 114 stores various data including programs executed by the CPU 111.

  The TPM chip 115 encrypts data stored in the HDD 114 using an encryption key. Since the TPM chip 115 holds the encryption key in the built-in memory, it is resistant to external attacks. By using the TPM chip 115, the risk of information leakage due to theft or analysis of data from the HDD 114 can be reduced.

  The PHY chip 116 converts the logic signal output from the ASIC 113 into an electrical signal and outputs the electrical signal. The PHY chip 116 converts an electrical signal input from an external device into a logic signal and inputs the logic signal to the ASIC 113.

  The operation panel 12 is an input / output device of the image forming apparatus 1. The operation panel 12 includes a hardware key and a touch panel as an input device. The operation panel 12 includes a display device such as a liquid crystal display and a speaker as an output device. The operation panel 12 is connected to the ASIC 113 by a data transfer bus 117.

  The FCU 13 controls the fax function. Specifically, the FCU 13 controls fax transmission / reception using a public switched telephone network (PSTN) or an integrated services digital network (ISDN). The FCU 13 controls registration and citation of various fax data managed by the backup memory, fax reading, fax reception printing, and the like.

  The USB device 14 is a peripheral device connected using USB. The USB device 14 is a two-dimensional code reader or the like.

  The engine 16 controls a printing device and a reading device, and realizes a printing function and a scanner function. The engine 16 includes a print engine that controls the printing apparatus and a scan engine that controls the reading apparatus.

  FIG. 3 is a diagram illustrating an example of the software group 5 provided in the image forming apparatus 1. Each software included in the software group 5 is stored in the HDD 114, read into the system memory 112, and executed by the CPU 111. Thereby, various functions of the image forming apparatus 1 are realized.

  Each software included in the software group 5 is executed in parallel as a process on an OS such as UNIX (registered trademark). The software group 5 includes software included in the application layer 51 and software included in the platform 52.

  The application layer 51 includes software that performs processing unique to various services related to image formation. The application layer 51 includes a printer application (PRINT) 511, a copy application (COPY) 512, and a fax application (FAX) 513. The application layer 51 includes a scanner application (SCAN) 514 and a net file application (NET FILE) 515.

  The platform 52 includes a gateway application programming interface (GWAPI) 53, a control service layer 54, a system resource manager (SRM) 55, and a handler layer 56.

  The GWAPI 53 enables the platform to receive a processing request from the application layer 51 using a predefined function.

  The control service layer 54 includes one or more service modules, interprets a processing request from the application layer 51, and generates an acquisition request for the ASIC 113. The control service layer 54 includes an NCS (Network Control Service) 521, an OCS (Operation Control Service) 542, an FCS (Fax Control Service) 543, and an MCS (Memory Control Service) 544.

  The control service layer 54 includes an ECS (Engine Control Service) 545, a DCS (Delivery Control Service) 546, a CCS (Certification and charge Control Service) 547, and an LCS (Log Control Service) 548. The control service layer 54 includes a user information control service (UCS) 549 and a system control service (SCS) 550.

  The NCS 521 provides a service that can be commonly used by one or more software (applications) that require network I / O. For example, the NCS 521 distributes data received from the network to each software. In addition, the NCS 521 performs mediation for transmitting data from the software to the network.

  The OCS 542 controls the operation panel 12.

  The FCS 543 provides APIs for fax transmission / reception using PSTN and ISDN, registration and citation of various types of fax data managed in a backup memory, fax reading, fax reception printing, and the like.

  The MCS 544 performs memory control such as securing and releasing the system memory 112 and using the HDD 114. The ECS 545 controls the engine 16. The DCS 546 controls distribution of stored documents and the like. The CCS 547 performs control related to authentication and charging. The LCS 548 manages and holds log information. The UCS 549 manages user information.

  The SCS 550 performs management of the ASIC 113 and application, LED display, interrupt application control, and the like.

  The SRM 55 is a lower layer of a service module such as the NCS 521, and arbitrates acquisition requests from the control service layer 54 in accordance with the resource usage status. The SRM 55 controls the ASIC 113 together with the SCS 550.

  When an upper layer such as the NCS 521 generates an acquisition request for the ASIC 113 in response to a processing request from the application layer 51, the SRM 55 determines whether the ASIC 113 requested for acquisition can be used. When the ASIC 113 is available, the SRM 55 notifies the upper layer to that effect. Further, the SRM 55 performs scheduling for using the ASIC 113 in response to an acquisition request from an upper layer, and executes request contents (for example, memory reservation, file generation, imaging, paper conveyance, etc.).

  The handler layer 56 manages the ASIC 113 in response to an acquisition request from the SRM 55. The handler layer 56 includes an FCUH (Fax Control Unit Handler) 561, an IMH (Image Memory Handler) 562, and an MEU 563.

  The FCUH 561 manages the FCU 13.

  The IMH 562 performs allocation of the system memory 112 to processes and management of the allocated system memory 112.

  The MEU 563 performs control related to image conversion.

  As an example of the operation of the image forming apparatus 1, image reading processing will be described. In the image forming apparatus 1, the printer application 511, the copy application 512, and the scanner application 514 execute an image reading process.

  When the application generates a processing request for reading processing, the processing request is input to the controller 11 via the platform 52. The controller 11 controls the imaging device according to the input processing request and executes image reading.

  The read image is stored in the system memory 112, encrypted by the TPM chip 115 and stored in the HDD 114 in accordance with the setting of the application or the device setting that generated the processing request.

  FIG. 4 is a diagram illustrating an example of a hardware configuration of the server 2. 4 includes a CPU 201, a ROM 202, a RAM 203, an HDD 204, an input device 205, a display device 206, a communication interface 207, and a bus 208.

  The CPU 201 executes the program to control each configuration and realize the function of the server 2. The ROM 202 stores various data including a program executed by the CPU 201. The RAM 203 provides a work area for the CPU 201. The HDD 204 stores various data including a program executed by the CPU 201. The input device 205 receives an operation from the user and inputs information corresponding to the received operation to the server 2. The input device 205 is a mouse, a keyboard, hardware keys, a touch panel, or the like. The display device 206 displays images and videos. The display device 206 is a liquid crystal display, an organic EL display, a cathode ray tube display, or the like. The communication interface 207 is an interface for connecting the server 2 to the network 4. The bus 208 connects the CPU 201, the ROM 202, the RAM 203, the HDD 204, the input device 205, the display device 206, and the communication interface 207.

  Next, the functional configuration of the image forming apparatus 1 will be described. FIG. 5 is a diagram illustrating an example of a functional configuration of the image forming apparatus 1. The image forming apparatus 1 in FIG. 5 includes an engine control unit 101, a digital watermark control unit 102, a digital watermark information generation unit 103, an embedded information generation unit 104, an identifier generation unit 105, an image management unit 106, and options. A storage unit 107. These functional configurations are realized by the CPU 111 executing a program.

  The engine control unit 101 transmits an instruction such as a print instruction or a read instruction to the engine 16 to control the engine 16. Upon receiving a print instruction from the engine control unit 101, the engine 16 controls the printing apparatus and executes printing. When the engine 16 receives a reading instruction from the engine control unit 101, the engine 16 controls the reading device and executes reading.

  The digital watermark control unit 102 (registration unit, second embedding method acquisition unit, second additional information acquisition unit, identification information acquisition unit, additional information provision unit, read image acquisition unit) The overall processing related to digital watermarking, such as the reading process, is controlled. The digital watermark here is an image having predetermined additional information embedded (added) in a print image. Additional information included in the digital watermark is referred to as digital watermark information. By embedding the digital watermark in the print image, the digital watermark information can be embedded in the print image. Further, by reading the digital watermark embedded in the print image, the digital watermark information embedded in the print image can be acquired. The digital watermark control unit 102 generates a digital watermark based on the embedded information and the digital watermark information. Details of the internal configuration of the digital watermark control unit 102 will be described later.

  The digital watermark information generation unit 103 (first additional information acquisition unit) acquires digital watermark information by generating digital watermark information. The digital watermark information generation unit 103 may generate digital watermark information based on information held by the image forming apparatus 1, or based on information received from the server 2 or the user terminal 3. May be generated. The digital watermark information can be arbitrarily set. The digital watermark information may include information about the user and information about the image forming apparatus 1. For example, in order to track when, where, and by whom the printed material is printed, the digital watermark information generating unit 103 includes device identification information such as the IP address and machine number information of the image forming apparatus 1 that printed the printed material, Information obtained by acquiring user identification information such as a user ID of a user who has performed printing (for example, a user who has logged in to the image forming apparatus 1) and date / time information indicating the date and time of printing from the image forming apparatus 1. Is generated.

  The embedded information generation unit 104 (first embedding method acquisition unit) acquires (determines) a digital watermark embedding method by generating embedded information based on the digital watermark information. The embedding information is information indicating a method for embedding a digital watermark in a print image. The digital watermark is embedded in the print image using the embedded information. The embedding information includes a digital watermark embedding position, an embedding pattern, an embedding size, and an embedding bit number. However, the embedded information is not limited to these.

  The embedding position is information indicating a position where a digital watermark is embedded in a print image. The embedding information generation unit 104 selects any one option from the options of embedding positions registered in advance. The choice of the embedding position may be an area such as “upper left”, “upper right”, “lower left”, “lower right”, or the coordinates of the print image. The embedded information generation unit 104 may randomly select an option from these options, or may select an option according to some logic (for example, ascending or descending order of options).

  The embedding pattern is information indicating the shape of the digital watermark. The embedding information generation unit 104 selects any one option from among pre-registered embedding pattern options. Options for the embedding pattern are, for example, “straight line”, “square”, “triangle”, “circular”, “ellipse”, and the like. The embedded information generation unit 104 may randomly select an option from these options, or may select an option according to some logic (for example, ascending or descending order of options).

  The embedding size is information indicating the size of the digital watermark. The embedding information generation unit 104 selects any one option from among pre-registered embedding size options. The embedded size option may be, for example, a relative value such as “25%”, “50%”, “75%”, “100%”, or “10 mm” with respect to a preset reference size. It may be an absolute value such as “20 mm” or “30 mm”. The embedded information generation unit 104 may randomly select an option from these options, or may select an option according to some logic (for example, ascending or descending order of options).

The number of embedded bits is the number of unit images (bits) constituting the digital watermark. The unit image is an image such as a quadrangle, a triangle, or a circle. The digital watermark is composed of unit images arranged along an embedding pattern. Here, it is assumed that the unit image has one of two preset colors. This corresponds to the fact that each unit image can take either 0 or 1 value. When the number of embedded bits is n bits, the digital watermark can hold 2 ⁿ bits of information.

Note that the color of the unit image is preferably a color that is difficult to visually recognize (yellow or white) so that a digital watermark is not easily grasped by a third party. Further, m (≧ 3) colors may be prepared in advance as the color of the unit image. This corresponds to the fact that each unit image can take one of m values. When the number of embedded bits is n bits, the digital watermark can hold m ⁿ bits of information.

  The embedded information generation unit 104 determines the number of embedded bits based on the data size of the digital watermark information and the number of values (colors) that each unit image can take. When each unit image can take a binary value, the embedded information generating unit 104 converts the digital watermark information into a bit string, and determines the number of bits of the obtained bit string as the number of embedded bits. Therefore, the number of embedded bits is a value corresponding to the data size of the digital watermark information.

  Note that the embedding information generation unit 104 may select one of the options of the number of embedded bits registered in advance. In this case, the embedded information generation unit 104 may select an option larger than the number of bits obtained by the above method from the data size of the digital watermark information.

  Through the above processing, embedding information including a digital watermark embedding position, an embedding pattern, an embedding size, and an embedding bit number is generated.

  The identifier generation unit 105 generates an identifier for uniquely identifying embedded information in the system. The method for generating the identifier is arbitrary. Further, the identifier generation unit 105 generates an identifier image based on the generated identifier. The identifier image is an image indicating an identifier (identification information). That is, the identifier image has an identifier as information. The identifier image may be a text image indicating the identifier or may be an embedded pattern corresponding to the identifier. The method for generating the identifier image will be described later in detail.

  The image management unit 106 (embedding execution unit) holds a print image received from the user terminal 3 or the like, and embeds (synthesizes) a digital watermark and an identifier image in the print image.

  FIG. 6 is a diagram illustrating an example of the internal configuration of the digital watermark control unit 102. The digital watermark control unit 102 in FIG. 6 includes a digital watermark generation unit 1021, a communication unit 1022, an identifier acquisition unit 1023, and a digital watermark information acquisition unit 1024.

  The digital watermark generation unit 1021 generates a digital watermark based on the digital watermark information and the embedded information, and calculates the embedded coordinates of the generated digital watermark. Details of the digital watermark generation method will be described later.

  The communication unit 1022 communicates with the server 2. The communication unit 1022 transmits embedded information and an identifier to the server 2 at the time of print processing. The server 2 stores the embedded information received from the communication unit 1022 and the identifier in association with each other. In the reading process, the communication unit 1022 transmits an identifier included in the identifier image read from the printed material to the server 2 and receives embedded information corresponding to the identifier from the server 2.

  The identifier acquisition unit 1023 reads the identifier image from the print image read from the printed material, and acquires the identifier included in the identifier image. The method for acquiring the identifier will be described later in detail.

  Based on the embedded information, the digital watermark information acquisition unit 1024 reads a digital watermark from a print image read from a printed material, and acquires digital watermark information included in the digital watermark. The method for acquiring the digital watermark information will be described later in detail.

  In the present embodiment, the communication unit 1022, the identifier acquisition unit 1023, and the digital watermark information acquisition unit 1024 are included in the digital watermark control unit 102, but may be provided as independent functional configurations.

  The option storage unit 107 stores options of embedded information registered in advance. Specifically, the option storage unit 107 stores options for an embedding position, an embedding pattern, and an embedding size. The option storage unit 107 may store options for the number of embedded bits. The embedded information generation unit 104 selects one option from the options stored in the option storage unit 107, and generates embedded information.

  Next, the operation of the system according to this embodiment will be described. Hereinafter, a print process for printing a print image on a print medium and a read process for reading the print image from a printed material will be described.

  First, the printing process will be described. FIG. 7 is a sequence diagram illustrating an example of the printing process. It is assumed that the image forming apparatus 1 has received a print image from the server 2 or the user terminal 3 at the start of the sequence in FIG. 7, and the print image is held in the image management unit 106.

  First, the user operates the operation panel 12 of the image forming apparatus 1 and instructs the engine control unit 101 to execute printing (step S101). The user may instruct execution of printing from the user terminal 3.

  When instructed to execute printing, the engine control unit 101 requests the digital watermark control unit 102 to embed a digital watermark in a print image (step S102).

  When requested to embed a digital watermark in a print image, the digital watermark control unit 102 requests the digital watermark information generation unit 103 to generate digital watermark information (step S103).

  When requested to generate digital watermark information, the digital watermark information generation unit 103 generates digital watermark information based on information held by the image forming apparatus 1 or information received from the user terminal 3 (step S104). When generating the digital watermark information, the digital watermark information generation unit 103 passes the generated digital watermark information to the digital watermark control unit 102 (step S105).

  Upon receiving the digital watermark information, the digital watermark control unit 102 requests the embedded information generation unit 104 to generate embedded information (step S106). At this time, the digital watermark control unit 102 passes the digital watermark information to the embedded information generation unit 104.

  When requested to generate embedded information, the embedded information generating unit 104 generates embedded information (step S107). FIG. 8 is a flowchart illustrating an example of the embedded information generation process. The flowchart in FIG. 8 corresponds to the internal processing in step S107. FIG. 9 is a diagram illustrating a specific example of the embedded information generation process.

  First, the embedding information generation unit 104 selects any one of pre-registered embedding position options (step S1071). In the example of FIG. 9, “upper left” is selected from among “upper left”, “upper right”, “lower left”, and “lower right”. In the example of FIG. 9, it is assumed that the print image is divided into four parts. However, the print image may be divided into nine parts or 16 parts.

  Next, the embedding information generation unit 104 selects any one of pre-registered embedding pattern options (step S1072). In the example of FIG. 9, “ellipse” is selected from “straight line”, “square”, “triangle”, and “ellipse”.

  Subsequently, the embedding information generation unit 104 selects any one of pre-registered embedding size options (step S1073). In the example of FIG. 9, “50%” is selected from “25%”, “50%”, “75%”, and “100%”.

  Further, the embedded information generation unit 104 converts the digital watermark information into a bit string and determines the number of embedded bits (step S1074). In the example of FIG. 9, the digital watermark information is “abc”. When this digital watermark information is converted into a bit string, it is represented by 24 bits. Therefore, the number of embedded bits is determined to be 24 bits.

  Through the above processing, embedding information including an embedding position, an embedding pattern, an embedding size, and the number of embedding bits is generated. In the example of FIG. 9, the embedding position of the embedding information is “upper left”, the embedding pattern is “ellipse”, the embedding size is “50%”, and the embedding bit number is “24 bits”. Note that the order of steps S1071 to S1074 is arbitrary.

  When the embedding information is generated, the embedding information generation unit 104 passes the generated embedding information to the digital watermark control unit 102 as shown in FIG. 7 (step S108).

  When the digital watermark control unit 102 receives the embedded information, the digital watermark generation unit 1021 generates a digital watermark based on the received embedded information and the digital watermark information, and calculates embedded coordinates for embedding the generated digital watermark. (Step S109).

  FIG. 10 is a flowchart illustrating an example of a digital watermark generation process. The flowchart in FIG. 10 corresponds to the internal processing in step S109. FIG. 11 is a diagram illustrating a specific example of digital watermark generation processing. In the following, it is assumed that a digital watermark is generated based on the embedded information shown in FIG.

  First, the digital watermark generation unit 1021 converts the digital watermark information into a bit string (step S1091). The digital watermark generation unit 1021 may receive a bit string from the embedded information generation unit 104. Here, a 24-bit bit string is generated.

  Next, the digital watermark generation unit 1021 generates an array of unit images corresponding to the generated bit string (step S1092). When the unit image corresponding to the 0 bit is a white square and the unit image corresponding to the 1 bit is a black square, a total of 24 white square and black square arrays are generated.

  Note that the digital watermark generation unit 1021 may add a dummy arrangement of unit images to the end of the arrangement of unit images corresponding to the digital watermark information. The dummy array is an array having no digital watermark information, and can be configured by randomly arranging unit images of respective colors. By adding a dummy array, it is possible to suppress theft or falsification of digital watermark information and improve safety.

  Next, the digital watermark generation unit 1021 calculates reference coordinates (x0, y0) for embedding the digital watermark based on the embedded position of the digital watermark (step S1093). The reference coordinates (x0, y0) are, for example, coordinates such as the center and vertex of the embedding position (area). In the example of FIG. 11, the coordinates of the center of the upper left area of the print image are calculated as the reference coordinates (x0, y0).

  Next, the digital watermark generation unit 1021 calculates the digital watermark embedding start coordinates (xs1, ys1) (step S1094). The embedding start coordinates (xs1, ys1) correspond to the embedding coordinates of the unit image corresponding to the first bit of the digital watermark information. The relative position of the embedding start coordinates (xs1, ys1) with respect to the reference coordinates (x0, y0) is set in advance for each embedding pattern. The digital watermark generation unit 1021 may store a relative position for each embedding pattern in advance or may receive it from the embedding information generation unit 104. The digital watermark generation unit 1021 can calculate the embedding start coordinates (xs1, ys1) based on the relative position and the reference coordinates (x0, y0).

  Next, the digital watermark generation unit 1021 arranges the array of unit images generated in step S1092 along the digital watermark embedding pattern from the embedding start coordinates (xs1, ys1), and calculates the embedded coordinates of each unit image. (Step S1095). Thereby, the coordinates of each unit image constituting the digital watermark are respectively calculated. In the example of FIG. 11, 24 unit images are arranged clockwise from the embedding start coordinates (xs1, ys1) along the ellipse. In step S1095, the digital watermark generation unit 1021 calculates the embedded coordinates of each unit image on the assumption that the size of the digital watermark is the reference size.

  Next, the digital watermark generation unit 1021 adjusts the embedding coordinates of each unit image based on the embedding size of the digital watermark (step S1096). That is, the digital watermark generation unit 1021 calculates the embedded coordinates of each unit image when the size of the digital watermark is adjusted to the embedded size. In the example of FIG. 11, the embedded coordinates of 24 unit images when the size of the ellipse is adjusted to 50% of the reference size are calculated.

  Through the above processing, a digital watermark is generated, and embedded coordinates of each unit image constituting the digital watermark are calculated. Note that step S1095 described above may be omitted.

  When generating the digital watermark, the digital watermark control unit 102 requests the identifier generation unit 105 to generate an identifier as shown in FIG. 7 (step S110).

  When the identifier generation unit 105 is requested to generate an identifier, the identifier generation unit 105 generates an identifier and an identifier image, and calculates embedded coordinates of the identifier image (step S111). An identifier generation method is arbitrary as described above.

  FIG. 12 is a flowchart illustrating an example of an identifier image generation process. The flowchart in FIG. 12 corresponds to the internal processing in step S111. FIG. 13 is a diagram showing a specific example of the identifier image generation process.

  First, the identifier generation unit 105 generates an electronic watermark identifier (step S1111). Here, it is assumed that the identifier is “123”.

  Next, the identifier generation unit 105 converts the identifier into a bit string (step S1112). As a result, a first bit string corresponding to the identifier is generated. When the identifier is “123”, the first bit string “100100011” is generated.

  Next, the identifier generation unit 105 generates a second bit string indicating the number of bits of the first bit string and adds it to the head of the first bit string (step S1113). The number of bits of the second bit string is set in advance.

  When the number of bits of the second bit string is 8 bits, since the number of bits of the first bit string is 9 bits, the second bit string “00000101” is generated. By adding this second bit string to the head of the first bit string “100100011”, a third bit string “0000100001100100011” is generated.

  Next, the identifier generation unit 105 generates an array of unit images corresponding to the generated third bit string (step S1114). The unit images constituting the identifier image may be the same as or different from the unit images constituting the digital watermark. If the unit image corresponding to the 0 bit is a white square, and the unit image corresponding to the 1 bit is a black square, a total of 17 white square and black square arrays are generated.

  The identifier generation unit 105 may add a dummy arrangement of unit images to the end of the arrangement of unit images corresponding to the third bit string. The dummy array is an array that does not indicate an identifier, and can be configured by randomly arranging unit images of each color. By adding a dummy array, it is possible to suppress theft or falsification of identifiers and improve safety.

  Next, the identifier generation unit 105 calculates embedded coordinates of each unit image constituting the identifier image (step S1115). In the present embodiment, the embedding start coordinates and the embedding pattern of the identifier image are set in advance. The embedding start coordinates and the embedding pattern of the identifier image can be arbitrarily set. The identifier generation unit 105 arranges the third array of unit images generated in step S1114 from the embedding start coordinates along the embedding pattern of the identifier image, and calculates the embedding coordinates of each unit image. Thereby, the coordinates of each unit image constituting the identifier image are respectively calculated.

  In the example of FIG. 13, four embedding start coordinates (xs2, ys2) to (xs5, ys5) are set, and 17 unit images are printed images along the horizontal straight line from each embedding start coordinate. It is arranged toward the outside. Specifically, the unit images are arranged in the left direction from the embedding start coordinates (xs2, ys2), (xs4, ys4), and the right direction from the embedding start coordinates (xs3, ys3), (xs5, ys5). Unit images are arranged in In either case, a unit image corresponding to the first bit of the identifier is arranged at the embedding start coordinate.

  Through the above processing, an identifier image is generated, and the embedded coordinates of each unit image constituting the identifier image are calculated.

  When the identifier generation unit 105 generates the identifier and the identifier image, the identifier generation unit 105 passes the identifier, the identifier image, and the embedded coordinates thereof to the digital watermark control unit 102.

  When the digital watermark control unit 102 receives the identifier, the identifier image, and the embedded coordinates thereof, the communication unit 1022 transmits the received identifier and the embedded information received in step S108 to the server 2 (step S113). When the server 2 receives the identifier and the embedded information from the communication unit 1022, the server 2 stores the received identifier and the embedded information in association with each other. As a result, the print image in which the digital watermark information is embedded based on the embedded information and the embedded information (embedding method) are registered in the server 2 in association with each other. The print image and the embedded information registered in association with each other are referred to as registration information. The digital watermark control unit 102 may transmit these pieces of information to the server 2 after receiving a notification of completion of embedding a digital watermark and an identifier image, which will be described later. Further, the digital watermark control unit 102 may transmit these pieces of information to the server 2 after being notified directly or indirectly from the engine 16 that printing has been completed (for example, paper discharge completion). When the electronic watermark control unit 102 is notified of the completion of embedding or the completion of printing and transmits to the server 2, the print image in which the electronic watermark information is embedded based on the embedded information and the embedded information are transmitted to the server 2. (Embedding method) is registered in association with each other.

  FIG. 14 is a diagram illustrating an example of identifiers and embedded information stored in the server 2. In the example of FIG. 14, an identifier, embedding information (embedding position, embedding pattern, embedding size and number of embedding bits), and printing time are stored in association with each other. For example, the identifier “123” is stored in association with “upper left”, “ellipse”, “50%”, “24 bits”, and “7/7 13:00”.

  As shown in FIG. 14, the server 2 stores the identifiers so as not to overlap. When the server 2 receives an identifier from one image forming apparatus 1, the identifier generation unit 105 of the image forming apparatus 1 may generate an identifier based on, for example, the printing date and time. Thereby, duplication of identifiers can be prevented.

  When the server 2 receives identifiers from a plurality of image forming apparatuses 1, the identifier generation unit 105 of each image forming apparatus 1 is based on, for example, the printing date and the unique identifier (for example, MAC address) of each image forming apparatus 1. An identifier may be generated. Thereby, duplication of identifiers can be prevented.

  When the server 2 receives identifiers from a plurality of image forming apparatuses 1, the server 2 may store the identifier for each image forming apparatus 1. Thereby, even if the identifiers generated by the image forming apparatuses 1 are duplicated, the server 2 can store the identifiers so that the identifiers are not duplicated.

  Next, as shown in FIG. 7, the digital watermark control unit 102 instructs the image management unit 106 to embed a digital watermark and an identifier image in the print image (step S114). At this time, the digital watermark control unit 102 passes the digital watermark and its embedded coordinates, and the identifier image and its embedded coordinates to the image management unit 106.

  When instructed to embed in the print image, the image management unit 106 embeds the digital watermark and the identifier image in the respective embedded coordinates in the print image (step S115). As a result, a print image in which the electronic watermark information and the identifier are embedded as information is generated.

  When the embedding of the digital watermark and the identifier image is completed, the image management unit 106 notifies the digital watermark control unit 102 that the embedding of the digital watermark and the identifier image has been completed (step S116).

  When notified that the embedding is completed, the digital watermark control unit 102 notifies the engine control unit 101 that the embedding of the digital watermark into the print image is completed (step S117).

  When notified of the completion of embedding, the engine control unit 101 instructs the engine 16 to start printing (step S118). In addition, the engine control unit 101 instructs the image management unit 106 to start transfer of a print image (step S119).

  When instructed to start the transfer of the print image, the image management unit 106 transfers the print image in which the digital watermark and the identifier image are embedded to the engine 16 (step S120). The engine 16 controls the printing apparatus and prints the print image received from the image management unit 106.

  Through the above processing, the image forming apparatus 1 can print the print image in which the digital watermark and the identifier image are embedded on the print medium.

  Next, the reading process will be described. The reading process may be executed by the image forming apparatus 1 that has performed the printing process after the printing process, or another image forming apparatus that can communicate with the same server 2 as the image forming apparatus 1 that has performed the printing process. 1 may be executed. For example, in the example of FIG. 1, it is conceivable that the image forming apparatus 1 a executes a printing process and the image forming apparatus 1 b executes a reading process.

  FIG. 15 is a sequence diagram illustrating an example of the reading process. Hereinafter, it is assumed that the image forming apparatus 1 reads a printed matter printed by the printing process of FIG. In this case, the identifier and the embedded information corresponding to the printed matter to be read are stored in the server 2.

  First, the user places a printed material at a predetermined position of the image forming apparatus 1, operates the operation panel 12 of the image forming apparatus 1, and instructs the engine control unit 101 to execute reading (step S201). The user may instruct execution of reading from the user terminal 3.

  When instructed to execute reading, the engine control unit 101 instructs the engine 16 to start reading (step S202). When the engine 16 is instructed to start reading, the engine 16 controls the reading device and executes reading of the printed matter installed by the user. Thereby, the printed image printed on the surface of printed matter is read. The read print image is referred to as a read image. A digital watermark and an identifier image are embedded in this read image.

  When the engine 16 reads the printed matter, the engine 16 transfers the obtained read image to the image management unit 106 (step S203). The image management unit 106 stores the read image received from the engine 16 and passes the read image to the engine control unit 101 (step S204).

  Upon receiving the read image, the engine control unit 101 requests the digital watermark control unit 102 to read the digital watermark from the read image (step S205). At this time, the engine control unit 101 passes the read image received from the image management unit 106 to the digital watermark control unit 102.

  When requested to read the digital watermark, the digital watermark control unit 102 acquires the read image passed from the engine control unit 101. Then, the identifier acquisition unit 1023 reads the identifier image embedded in the acquired read image, and acquires the identifier included in the identifier image (step S206).

  FIG. 16 is a flowchart illustrating an example of an identifier acquisition process. The flowchart in FIG. 16 corresponds to the internal processing in step S206.

  First, the identifier acquisition unit 1023 obtains an array of unit images having a preset number of bits, that is, an array of unit images corresponding to the second bit string, from the embedding start coordinates of the read image along the identifier image embedding pattern. Read (step S2061). Thereby, a second bit string is obtained. Specifically, the identifier acquisition unit 1023 reads the first to eighth unit images in the left direction or the right direction from at least one of the embedding start coordinates (xs2, ys2) to (xs5, ys5). . As a result, the second bit string “00000101” is obtained.

  Next, the identifier acquisition unit 1023 converts the acquired second bit string into a hexadecimal number, and acquires the number of bits of the identifier (step S2062). Specifically, the identifier acquisition unit 1023 acquires the bit number “9” by converting the second bit string “00000101” into a hexadecimal number.

  Next, the identifier acquisition unit 1023 changes the unit image array corresponding to the number of bits from the unit image next to the unit image array corresponding to the second bit string to the first bit string along the identifier image embedding pattern. The corresponding array of unit images is read (step S2063). As a result, the first bit string is obtained. Specifically, the identifier acquisition unit 1023 reads the ninth to seventeenth unit images in the unit image array. As a result, the first bit string “100100011” is obtained.

  Next, the identifier acquisition unit 1023 converts the acquired first bit string into a hexadecimal number and acquires an identifier (step S2064). Specifically, the identifier acquisition unit 1023 acquires the identifier “123” by converting the first bit string “100100011” into a hexadecimal number.

  As described above, the identifier acquisition unit 1023 acquires the identifier by reading the unit image array from the head (embedding start coordinates) by a predetermined number of bits. Therefore, the identifier acquisition unit 1023 can acquire the identifier even when a dummy array is added to the end of the array of unit images corresponding to the third bit string.

  When the identifier acquisition unit 1023 acquires the identifier, the identifier acquisition unit 1023 transmits the identifier to the server 2 and requests acquisition of embedded information corresponding to the identifier (step S207). When the server 2 is requested to acquire the embedded information, the server 2 refers to the registration information and transmits the embedded information corresponding to the received identifier to the identifier acquiring unit 1023 (step S208). The identifier acquisition unit 1023 receives this embedded information. Thereby, the identifier acquisition unit 1023 can acquire embedded information corresponding to the identifier.

  When the identifier acquisition unit 1023 acquires the embedded information, based on the embedded information, the digital watermark information acquisition unit 1024 reads the digital watermark embedded in the read image, and acquires the digital watermark information included in the digital watermark (Step S1). S209).

  FIG. 17 is a flowchart illustrating an example of an electronic watermark information acquisition process. The flowchart in FIG. 17 corresponds to the internal processing in step S209.

  First, the digital watermark information acquisition unit 1024 calculates reference coordinates (x0, y0) based on the embedding position (step S2091). The calculation method of the reference coordinates (x0, y0) is as described above.

  Next, the digital watermark information acquisition unit 1024 calculates the embedding start coordinates (xs1, ys1) based on the reference coordinates (x0, y0) and the relative position corresponding to the embedding pattern (step S2092).

  Next, the digital watermark information acquisition unit 1024 uses each of the unit images included in the array of unit images corresponding to the digital watermark information based on the embedding start coordinates (xs1, ys1), the embedding pattern, and the number of embedding bits. Embedded coordinates are calculated (step S2093). Specifically, the digital watermark information acquisition unit 1024 embeds bits embedded along the embedding pattern from the unit image corresponding to the first bit of the digital watermark information disposed at the embedding start coordinates (xs1, ys1). Calculate the embedded coordinates of the unit image for several minutes. In step S2093, the digital watermark information acquisition unit 1024 calculates the embedded coordinates of each unit image on the assumption that the size of the digital watermark is the reference size.

  Next, the digital watermark information acquisition unit 1024 adjusts the embedding coordinates of each unit image based on the embedding size (step S2094). That is, the digital watermark information acquisition unit 1024 calculates the embedded coordinates of each unit image when the size of the digital watermark is adjusted to the embedded size. The embedded coordinates calculated in step S2094 correspond to the actual embedded coordinates of the unit image embedded in the read image.

  Next, the digital watermark information acquisition unit 1024 reads an array of unit images corresponding to the digital watermark information based on the embedded coordinates of the unit images (step S2095). Thereby, a bit string corresponding to the digital watermark information is obtained.

  Next, the digital watermark information acquisition unit 1024 converts the acquired bit string into a hexadecimal number, and acquires digital watermark information (step S2096).

  In this way, the digital watermark information acquisition unit 1024 acquires digital watermark information by reading the unit image array from the head (embedding start coordinates) by the number of embedded bits. Therefore, the digital watermark information acquisition unit 1024 can acquire digital watermark information even when a dummy array is added to the end of the array of unit images corresponding to the digital watermark information.

  Upon acquiring the digital watermark information, the digital watermark information acquisition unit 1024 transmits (provides) the digital watermark information to the operation panel 12 (step S210). When receiving the digital watermark information, the operation panel 12 displays the digital watermark information on the display device. Also, the digital watermark information acquisition unit 1024 may provide the acquired digital watermark information to another device such as an administrator PC or a management server via a network. In this case, another apparatus can store or display the digital watermark information provided from the image forming apparatus 1, and can create a report based on the provided digital watermark information.

  Through the above processing, the image forming apparatus 1 can read the digital watermark from the read image and acquire the digital watermark information.

  As described above, according to the present embodiment, the digital watermark embedding position, embedding pattern, and embedding size can be changed while the digital watermark can be read. This makes it difficult for a third party to know where the digital watermark is embedded in the print image. As a result, it is possible to suppress the stealing and falsification of digital watermark information by a third party.

(Second Embodiment)
A system according to the second embodiment will be described with reference to FIGS. In the present embodiment, a method for updating options of embedded information registered in advance will be described. Specifically, an option adding method, a deleting method, and a changing method will be described. In the following, it is assumed that the user updates the options by operating the operation panel 12.

  First, the addition of options will be described. FIG. 18 is a sequence diagram illustrating an example of an option addition process. FIG. 19 is a diagram illustrating an example of screen transition of the operation panel 12 in the addition process.

  First, as shown in FIG. 18, the user selects a setting update button on the operation panel 12 (step S301). The setting update button may be a software key displayed on the operation panel 12 or a hardware key provided in the operation panel 12. When the user selects the setting update button, the operation panel 12 displays an update screen for selecting an option update method (step S302). The update screen displays selectable update methods. In the example of FIG. 19, “addition”, “deletion”, and “change” are displayed as selectable update methods.

  When the update screen is displayed, the user selects “add” displayed on the update screen as shown in FIG. 18 (step S303). When “add” is selected, the operation panel 12 displays a selection screen for selecting the embedded information to which the option is added (step S304). This selection screen displays embedded information to which options can be added. In the example of FIG. 19, “embedding position” and “embedding size” are displayed as embedding information to which options can be added.

  When the selection screen is displayed, as shown in FIG. 18, the user selects desired embedding information from the embedding information displayed on the selection screen (step S305). When the user selects embedded information, the operation panel 12 displays an addition screen for adding an option for the embedded information. The addition screen displays setting items constituting options of embedded information, input fields for inputting setting values of the setting items, and a registration button for executing addition of options. In the example of FIG. 19, the embedded size addition screen displays “registered name” and “magnification” as setting items. “Magnification” is a relative value with respect to the reference size.

  When the addition screen is displayed, as shown in FIG. 18, the user inputs a desired setting value in the input field of each setting item, and selects a registration button (step S307). When the registration button is selected, the operation panel 12 requests the embedded information generation unit 104 to register options (step S308). At this time, the operation panel 12 transmits the setting value of the setting item of the embedded information input by the user to the embedded information generation unit 104.

  When the registration of the option is requested, the embedded information generating unit 104 stores the option having the setting value received from the operation panel 12 in the option storage unit 107 and registers it as a new option (step S309). As a result, a new option of embedded information is added to the option storage unit 107. Thereafter, the added option is used to generate embedded information.

  Next, deletion of options will be described. FIG. 20 is a sequence diagram illustrating an example of the option deletion process. FIG. 21 is a diagram illustrating an example of screen transition of the operation panel 12 in the deletion process. Note that steps S401 and S402 in FIG. 20 are the same as steps S301 and S302 in FIG.

  When the update screen is displayed, the user selects “delete” displayed on the update screen as shown in FIG. 20 (step S403). When “delete” is selected, the operation panel 12 requests the embedded information generation unit 104 to acquire embedded information (step S404). When the embedded information generation unit 104 is requested to acquire embedded information, the embedded information generation unit 104 acquires the registered option of the embedded information from the option storage unit 107, and transmits the acquired option to the operation panel 12 (step S405).

  When the operation panel 12 receives the registered option of the embedded information, the operation panel 12 displays a deletion screen for selecting the option to be deleted (step S406). The deletion screen displays a list of registered options of embedded information and a delete button for executing the deletion of options.

  In the example of FIG. 20, the deletion screen displays “upper left”, “upper right”, “lower left”, and “lower right” as registered options of the embedded position, and “extra large” as registered options of the embedded size. (100%), “large (75%)”, “medium (50%)” and “small (25%)” are displayed.

  When the delete screen is displayed, as shown in FIG. 20, the user selects a desired option from the options displayed on the delete screen, and selects a delete button (step S407). When the delete button is selected, the operation panel 12 requests the embedded information generation unit 104 to delete the option (step S408). At this time, the operation panel 12 transmits the embedded information option selected by the user to the embedded information generation unit 104. When the embedded information generation unit 104 is requested to delete the option, the embedded information generation unit 104 deletes the option received from the operation panel 12 from the registered options stored in the option storage unit 107 (step S409).

  Next, the change of options will be described. FIG. 22 is a sequence diagram illustrating an example of the option change process. FIG. 23 is a diagram illustrating an example of screen transition of the operation panel 12 in the change process. Note that steps S501 and S502 in FIG. 22 are the same as steps S301 and S302 in FIG.

  When the update screen is displayed, the user selects “change” displayed on the update screen as shown in FIG. 22 (step S503). When “change” is selected, the operation panel 12 requests the embedded information generation unit 104 to acquire embedded information (step S504). When the embedded information generation unit 104 is requested to acquire embedded information, the embedded information generation unit 104 acquires the registered option of the embedded information from the option storage unit 107, and transmits the acquired option to the operation panel 12 (step S505).

  When the operation panel 12 receives the registered option of the embedded information, the operation panel 12 displays a change screen for selecting the option to be changed (step S506). The change screen displays a list of registered options of embedded information.

  In the example of FIG. 22, the change screen displays “upper left”, “upper right”, “lower left”, and “lower right” as registered options of the embedded position, and “extra large” as the registered options of the embedded size. (100%), “large (75%)”, “medium (50%)” and “small (25%)” are displayed.

  When the change screen is displayed, the user selects a desired option from the options displayed on the change screen as shown in FIG. 22 (step S505). When the user selects an option, the operation panel 12 displays a change screen for changing the option. The change screen displays setting items constituting the options, input fields in which setting values of the setting items are input, and a registration button for executing the change of the options. In the example of FIG. 23, the embedded size addition screen displays “registered name” and “magnification” as setting items. The setting value of “registered name” is “medium”, and the setting value of “magnification” is “50”.

  When the change screen is displayed, as shown in FIG. 22, the user changes the set value input in the input field of each setting item to a desired set value. For example, in the example of FIG. 23, it is conceivable to change the “magnification” of the embedding size. After changing the setting value, the user selects a registration button (step S507).

  When the registration button is selected, the operation panel 12 requests the embedded information generation unit 104 to register options (step S508). At this time, the operation panel 12 transmits the setting value changed by the user to the embedded information generation unit 104.

  When the embedded information generation unit 104 is requested to register options, the setting value received from the operation panel 12 is overwritten with the original setting value stored in the option storage unit 107, and the option overwritten with the setting value is displayed. Registration is performed (step S509). As a result, the embedded information options registered in the option storage unit 107 are changed. Thereafter, the changed option is used to generate embedded information.

  As described above, according to the present embodiment, it is possible to update (add, delete, and change) registered options of embedded information. When the user updates the options, it becomes more difficult for a third party to know where the digital watermark is embedded in the print image. As a result, it is possible to further suppress the stealing and falsification of digital watermark information by a third party. Moreover, the user can reduce the amount of information held by the option storage unit 107 by deleting unnecessary options.

  Note that the embedded information options may be updatable by an operation of the user terminal 3. The update of options by the user terminal 3 can be realized by replacing the operation panel 12 in the above description with the user terminal 3.

  Further, the embedded information options registered (stored) in the option storage unit 107 may be transmitted to the server 2. Thus, the embedded information options registered in the plurality of image forming apparatuses 1 can be centrally managed by the server 2, and the embedded information options can be shared among the plurality of image forming apparatuses 1. Also, the embedded information options may be directly registered in the server 2.

(Third embodiment)
A system according to the third embodiment will be described with reference to FIGS. In the present embodiment, a method for suppressing duplication of an embedded area of a digital watermark and an identifier image will be described.

  When the image forming apparatus 1 that performs the printing process overlaps the area in which the digital watermark and the identifier image are embedded in the print image, the image forming apparatus 1 that performs the reading process cannot correctly read the digital watermark and the identifier image. There is a risk that digital watermark information cannot be acquired. By preparing options for the embedding pattern and embedding size so that the digital watermark does not overlap the identifier image, duplication of the embedding area of the digital watermark and the identifier image can be prevented. However, in the above method, the degree of freedom of options decreases. In addition, when the user can update the options as in the second embodiment, the above method cannot prevent the digital watermark and the identifier image from being embedded.

  Therefore, in this embodiment, the digital watermark generation unit 1021 determines whether the digital watermark overlaps the identifier image when generating the digital watermark. For this determination, in the present embodiment, an overlapping region R is preset in the print image.

  The overlapping region R is a region where the digital watermark and the identifier image may overlap when a digital watermark unit image is included. The overlapping region R is set with reference to the embedding start coordinates of the identifier image. In this embodiment, when a digital watermark unit image is included in the overlap area R, it is determined that the digital watermark embedding area (first area) and the identifier image embedding area (second area) overlap.

  FIG. 24 is a diagram illustrating an example of the overlapping region R. In the example of FIG. 24, four overlapping regions R1 to R4 (shaded portions) are set in the print image. The overlapping regions R1 to R4 correspond to regions outside the embedding start coordinates (xs2, ys2) to (xs5, ys5) of the identifier image, respectively. Specifically, the overlapping area R1 is an upper left area from the embedding start coordinates (xs2, ys2), and the overlapping area R2 is an upper right area from the embedding start coordinates (xs3, ys3). The overlapping region R3 is a lower left region from the embedding start coordinates (xs4, ys4), and the overlapping region R4 is a lower right region from the embedding start coordinates (xs5, ys5). As illustrated in FIG. 24, when the digital watermark unit image is included in the overlapping region R, the digital watermark unit image and the identifier image unit image may overlap.

  In the example of FIG. 24, four overlapping regions R are set, but any number of overlapping regions R can be set. Further, the overlapping region R is not limited to a quadrangle as shown in FIG. 24, and can be set to an arbitrary shape.

  In the present embodiment, when the digital watermark unit image is included in the overlapping region R as shown in FIG. 24, the digital watermark generation unit 1021 moves the digital watermark so that the digital watermark does not overlap the identification image. Specifically, the digital watermark generation unit 1021 recalculates the embedded coordinates of each unit image so that all unit images of the digital watermark are not included in the overlapping region R.

  FIG. 25 is a flowchart illustrating an example of digital watermark generation processing in the present embodiment. The flowchart in FIG. 25 corresponds to a process in which steps S1097 to S1099 are added after step S1096 in FIG. FIG. 26 is a diagram illustrating a specific example of digital watermark generation processing. Hereinafter, steps S1097 to S1099 will be described.

  When the digital watermark generation unit 1021 adjusts the embedding coordinates of each unit image of the digital watermark, the digital watermark generation unit 1021 determines whether there is a unit image included in the overlapping region R (step S1097). Specifically, the digital watermark generation unit 1021 determines whether the embedded coordinates of each unit image are included in the overlapping region R. If there is no unit image included in the overlapping region R (NO in step S1097), the digital watermark generation process ends.

  On the other hand, when there is a unit image included in the overlapping area R (YES in step S1097), the digital watermark generation unit 1021 moves the movement distance (Δx, Δy) (change of the embedding area (first area) of each unit image. Amount) is determined (step S1098). Specifically, the digital watermark generation unit 1021 calculates the difference between the x coordinate and the y coordinate between the embedding coordinates of each unit image included in the overlapping area R and the embedding start coordinates of the identifier image serving as a reference for the overlapping area R. Calculate each. Then, the digital watermark generation unit 1021 determines the maximum value of the x-coordinate difference as the movement distance Δx in the x-axis direction, and determines the maximum value of the y-coordinate difference as the movement distance Δy in the y-axis direction.

  In the example of FIG. 26, unit images i, j, and k are included in the overlapping region R1. The embedded coordinates of the unit images i, j, and k are (xi, yi), (xj, yj), and (xk, yk), respectively. In this case, the digital watermark generation unit 1021 calculates | xi-xs2 |, | xj-xs2 |, | xk-xs2 |, | yi-ys2 |, | yj-ys2 |, | jk-ys2 |. The maximum value of the x coordinate difference is | xk−xs2 |, and the maximum value of the y coordinate difference is | yi−ys2 |. Therefore, the digital watermark generation unit 1021 determines the movement distance Δx in the x-axis direction as | xk−xs2 |, and determines the movement distance Δy in the y-axis direction as | yi-ys2 |.

  Note that the digital watermark generation unit 1021 considers the size of the unit image of the digital watermark and the identifier image, and calculates a movement distance (Δx, Δy) by adding a predetermined value to the maximum value of the difference between the x and y coordinates. ) May be determined.

  In the present embodiment, when the movement distance of each unit image is determined, the determined movement distance is transmitted as embedded information to the server 2 (step S113). The movement distance is stored by the server 2 in association with the embedding position, the embedding pattern, the embedding size, and the embedding bit number. That is, the embedded information stored in the server 2 includes an embedded position, an embedded pattern, an embedded size, the number of embedded bits, and a movement distance. If the movement distance is not determined, the movement distance is blank.

  Next, as shown in FIG. 25, the digital watermark generation unit 1021 moves the embedded coordinates of each unit image adjusted in step S1096 in a predetermined direction by a movement distance (Δx, Δy) (step S1099). The moving direction is a direction in which the digital watermark (each unit image) moves away from the overlapping region R (embedding start coordinates). In the present embodiment, the embedded coordinates of each unit image after movement correspond to the actual embedded coordinates of each unit image.

  In the example of FIG. 26, each unit image i, j, k is moved by the movement distance Δx in the right direction (x-axis positive direction) and moved by the movement distance Δy in the downward direction (y-axis positive direction). The embedded coordinates of the unit images i, j, and k after movement are (xi + Δx, yi + Δy), (xj + Δx, yj + Δy), and (xk + Δx, yk + Δy), respectively. Although not shown in FIG. 26, the digital watermark generation unit 1021 similarly moves the embedded coordinates of all unit images constituting the digital watermark.

  FIG. 27 is a flowchart illustrating an example of a digital watermark reading process according to this embodiment. The flowchart in FIG. 27 corresponds to a process in which steps S2097 to S2099 are added between steps S2094 and S2095 in FIG. Hereinafter, steps S2097 to S2099 will be described. In the present embodiment, the embedding information received by the image forming apparatus 1 in step S208 includes a moving distance.

  After adjusting the embedded coordinates of each unit image of the digital watermark, the digital watermark information acquisition unit 1024 determines whether the embedded information has a movement distance (whether the movement distance is blank) (step S2097). If there is no movement distance (NO in step S2097), that is, if the embedded coordinates of each unit image of the digital watermark are not moved, the process proceeds to step S2095.

  On the other hand, if there is a movement distance (YES in step S2097), that is, if the embedding coordinates of each unit image of the digital watermark are moved, the digital watermark information acquisition unit 1024 embeds each unit image adjusted in step S2096. The coordinates are moved in a predetermined direction by a movement distance (Δx, Δy) (step S2098). The moving direction is a direction in which the digital watermark (each unit image) moves away from the overlapping region R (embedding start coordinates). In the present embodiment, the embedded coordinates of each unit image after movement correspond to the actual embedded coordinates of each unit image. Thereafter, the process proceeds to step S2095.

  As described above, according to the present embodiment, the image forming apparatus 1 that performs the printing process moves the embedded coordinates of the digital watermark, thereby suppressing the overlap of the digital watermark and the identifier image. Thereby, the image forming apparatus 1 that performs the reading process can correctly read the digital watermark and the identifier image and acquire the identifier and the digital watermark information. That is, it is possible to improve the acquisition accuracy of the identifier and digital watermark information by the image forming apparatus 1 that performs the reading process.

  Further, according to the present embodiment, it is possible to suppress duplication of the digital watermark and the identifier image without depending on the choice of embedded information. Accordingly, it is possible to suppress duplication of the digital watermark and the identifier image while maintaining the flexibility of the choice of embedded information. Further, even when the choice of the embedded information is a buyable update by the user, it is possible to suppress duplication of the digital watermark and the identifier image.

  In each of the above embodiments, the case where the information processing apparatus that stores the identifier and the embedded information is the server 2 has been described as an example. However, the information processing apparatus may be the user terminal 3 or the image forming apparatus. 1 itself may be sufficient. When the information processing apparatus is the image forming apparatus 1, the image forming apparatus 1 that performs the printing process stores the identifier and the embedded information generated by itself and transmits them to the other image forming apparatuses 1. Thereby, the identifier and the embedded information generated by each image forming apparatus 1 are shared by each image forming apparatus 1 included in the system. As a result, the printing process and the reading process can be respectively executed by different image forming apparatuses 1 included in the system.

  In each of the above embodiments, generation of digital watermark information, embedded information, digital watermark and identifier, embedding in a print image, transmission of embedded information and identifier to the server 2, acquisition of embedded information from the server 2, identifier image The case where each process such as reading of the digital watermark and the digital watermark is performed in the image forming apparatus 1 has been described as an example. However, some or all of these processes may be performed in a server device (for example, server 2) connected to the image forming apparatus 1 via a network. In this case, the server apparatus may receive information necessary for each process from the image forming apparatus 1, execute each process, and return the execution result of each process to the image forming apparatus 1. The execution result includes the generated digital watermark information, embedded information, digital watermark or identifier, embedded print image, embedded information and transmission result of the identifier, embedded information acquired from the server 2, identifier read from the read image, or Digital watermarks are included. Note that when the server apparatus executes the above-described plurality of processes as a series of processes, the intermediate execution result does not have to respond to the image forming apparatus 1.

  In each of the above embodiments, the case where the embedding and reading of the digital watermark is performed in the image forming apparatus 1 has been described as an example. However, embedding and reading of the digital watermark may be performed in different image forming apparatuses.

  It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

1: Image forming apparatus 2: Server 3: User terminal 4: Network 101: Engine control unit 102: Digital watermark control unit 103: Digital watermark information generation unit 104: Embedded information generation unit 105: Identifier generation unit 106: Image management unit 1021 : Digital watermark generation unit 1022: Communication unit 1023: Identifier acquisition unit 1024: Digital watermark information acquisition unit

JP 2007-71008 A

Claims (10)

An information processing apparatus for embedding additional information in a print image by a plurality of embedding methods,
A first additional information acquisition unit that acquires additional information embedded in a print image;
A first embedding method acquisition unit that acquires the embedding method applied when embedding additional information in a print image from the plurality of embedding methods;
Applying the embedding method acquired by the first embedding method acquisition unit, and embedding the additional information acquired by the first additional information acquisition unit in a print image;
A registration unit that associates and registers the embedding method applied to the embedding process by the embedding execution unit and the print image that is the target of the embedding process;
An information processing apparatus comprising: The embedding execution unit embeds identification information for identifying the embedding method applied to the embedding process for the print image in the print image,
The registration unit associates and registers the embedding method applied to the embedding process for the print image by the embedding execution unit and the identification information embedded in the print image by the embedding execution unit. The information processing apparatus according to 1. The embedding execution unit changes the first area when the first area in which the additional information is embedded and the second area in which the identification information is embedded overlap in the print image. Embed information in the printed image,
The information processing apparatus according to claim 2, wherein the registration unit registers information indicating a change amount, the embedding method, and the print image in association with each other when the first area is changed. . A read image acquisition unit that acquires a read image generated by reading a printed matter on which a print image is printed;
From the registration information in which the print image and the embedding method applied when additional information is embedded in the print image among a plurality of embedding methods are registered in association with each other, A second embedding method acquisition unit for acquiring the embedding method corresponding to the print image;
A second additional information acquisition unit that acquires the additional information from the read image acquired by the read image acquisition unit based on the embedding method acquired by the second embedding method acquisition unit;
An additional information providing unit that provides the additional information acquired by the second additional information acquiring unit;
An information processing apparatus comprising: An identification information acquisition unit for acquiring identification information for identifying the embedding method from a specific position of the read image acquired by the read image acquisition unit;
The information processing apparatus according to claim 4, wherein the second embedding method acquisition unit acquires the embedding method corresponding to the identification information from the registration information based on the identification information acquired by the identification information acquisition unit. . The information according to any one of claims 1 to 5, wherein the embedding method includes at least one of an embedding position, an embedding pattern, an embedding size, and an embedding bit number when embedding the additional information in the print image. Processing equipment. An information processing method for embedding additional information in a print image by a plurality of embedding methods,
A first additional information acquisition step of acquiring additional information embedded in the print image;
A first embedding method acquisition step of acquiring the embedding method applied when embedding additional information in a print image from the plurality of embedding methods;
Applying the embedding method acquired in the first embedding method acquisition step and embedding the additional information acquired in the first additional information acquisition step in a print image; and
A registration step of registering the embedding method applied to the embedding processing in the embedding execution step and the print image that is the target of the embedding processing in association with each other;
An information processing method comprising: A read image acquisition step of acquiring a read image generated by reading a printed matter on which a print image is printed;
From the registration information in which the print image and the embedding method applied when additional information is embedded in the print image among a plurality of embedding methods are registered in association with each other, A second embedding method acquisition step of acquiring the embedding method corresponding to the print image;
A second additional information acquisition step for acquiring the additional information from the read image acquired by the read image acquisition step based on the embedding method acquired by the second embedding method acquisition step;
An additional information providing step of providing the additional information acquired in the second additional information acquisition step;
An information processing method comprising: A program for causing a computer to execute an information processing method for embedding additional information in a print image by a plurality of embedding methods,
A first additional information acquisition step of acquiring additional information embedded in the print image;
A first embedding method acquisition step of acquiring the embedding method applied when embedding additional information in a print image from the plurality of embedding methods;
Applying the embedding method acquired in the first embedding method acquisition step and embedding the additional information acquired in the first additional information acquisition step in a print image; and
A registration step of registering the embedding method applied to the embedding processing in the embedding execution step and the print image that is the target of the embedding processing in association with each other;
A program for causing a computer to execute the information processing method. A read image acquisition step of acquiring a read image generated by reading a printed matter on which a print image is printed;
From the registration information in which the print image and the embedding method applied when additional information is embedded in the print image among a plurality of embedding methods are registered in association with each other, A second embedding method acquisition step of acquiring the embedding method corresponding to the print image;
A second additional information acquisition step for acquiring the additional information from the read image acquired by the read image acquisition step based on the embedding method acquired by the second embedding method acquisition step;
An additional information providing step of providing the additional information acquired in the second additional information acquisition step;
A program that causes a computer to execute.

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