Image processing apparatus, control method of image processing apparatus and program

Abstract

To provide a mechanism in which an appropriate halftone pattern can be selected according to color components synthesizing an encoding pattern.SOLUTION: An image forming apparatus 102 performs image processing for printing of a printed matter in which additional information is embedded. The image forming apparatus 102 sets a halftone pattern that is used for halftone processing, from a plurality of halftone patterns 1-3. The image forming apparatus 102 determines whether or not an encoding pattern can be uniformly reproduced in a color plane in which encoding patterns generated on the basis of additional information are synthesized, when the set halftone pattern is used for the halftone processing. When it is determined that the encoding pattern cannot be uniformly reproduced, the image forming apparatus 102 changes the halftone pattern used for the halftone processing to other halftone pattern in which the encoding pattern can be uniformly reproduced in the color plane synthesizing encoding patterns when it is used for the halftone processing.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an image processing apparatus, a control method for an image processing apparatus, and a program. [Background technology]

[0002] There is a known digital watermarking technology that embeds additional information other than image information into an image (hereinafter referred to as "multiplexing"). In digital watermarking technology, for example, additional information such as the author's name and usage permission information is multiplexed into an image such as a photograph or painting so that it is difficult to visually distinguish. On the other hand, there are also cases where the additional information is multiplexed to increase the accuracy of extracting the additional information from the image, or to be intentionally seen on a white background, such as warning characters in a background pattern.

[0003] As a method of multiplexing additional information on an image, a technique is known in which pixel values ​​are modulated in a local region of the image, and a pattern image (hereinafter, referred to as "encoding pattern") representing the additional information is synthesized with the image. In Patent Document 1, an image is divided into blocks of 16 pixels (4×4 pixels), and the pixel values ​​of half of the 16 pixels (8 pixels) are modulated in the + direction, and the pixel values ​​of the remaining half of the 16 pixels are modulated in the - direction. The image synthesized with the encoding pattern in this way is printed by a printer or the like after halftone processing. The additional information present on the printed matter generated in this way is extracted by analyzing a scanned image of the printed matter and executing a decoding process. However, when halftone processing is performed on the encoding pattern, the reproducibility of some patterns is reduced, and ultimately the decoding may fail. For example, in a configuration using a dither method as halftone processing, if the screen angle of the color plane into which the encoding pattern is synthesized matches the angle of the encoding pattern, the encoding pattern will disappear. On the other hand, in a configuration using an error diffusion method that does not have a specific frequency component or angle, multiple patterns are not reproduced uniformly depending on the direction of error diffusion, and some patterns can be decoded but others cannot be decoded. In response to this, when a watermark image is synthesized, control is performed to change to a halftone pattern that is less likely to interfere with the encoded pattern (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-305429 A [Patent Document 2] JP 2010-213209 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the color components to be combined with the coding pattern are changed, the color components that interfere with the coding pattern also change, so it is necessary to select a halftone pattern that is less likely to interfere with the color components to be combined. However, in the above-mentioned Patent Document 2, the color components to be combined with the coding pattern are not taken into consideration when selecting a halftone pattern, so it is not possible to select an appropriate halftone pattern according to the color components to be combined.

[0006] An object of the present invention is to provide a mechanism for selecting an appropriate halftone pattern according to the color components with which a coding pattern is synthesized. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the image processing device of the present invention is an image processing device that performs image processing for printing a printed material in which additional information is embedded, and is equipped with a setting means for setting a halftone pattern to be used in the halftone processing from among a plurality of halftone patterns, and a judgment means for judging whether the coding pattern generated based on the additional information can be uniformly reproduced in a color plane into which the coding pattern is synthesized when the set halftone pattern is used in the halftone processing, and is characterized in that when the judgment means judges that the coding pattern cannot be uniformly reproduced, the setting means changes the halftone pattern to be used in the halftone processing to another halftone pattern that is judged to be able to uniformly reproduce the coding pattern in the color plane into which the coding pattern is synthesized when used in the halftone processing. Effect of the Invention

[0008] According to the present invention, an appropriate halftone pattern can be selected according to the color components with which the coding pattern is synthesized. [Brief description of the drawings]

[0009] [Figure 1] 10A and 10B are diagrams for explaining multiplexing of additional information and extraction of additional information in the present embodiment. [Diagram 2] 2 is a block diagram illustrating a schematic hardware configuration of the host PC illustrated in FIG. 1. [Diagram 3] 2 is a block diagram illustrating a schematic hardware configuration of the additional information multiplexing device of FIG. 1. [Figure 4] 4 is a flowchart showing the procedure of a multiplexing control process executed in the additional information multiplexing device of FIG. [Diagram 5] 2 is a diagram showing an example of a coding pattern that is synthesized onto image data by the additional information multiplexing device of FIG. 1. [Figure 6] 4 is a diagram for explaining a method of calculating pixel values ​​when the additional information multiplexing device in FIG. 1 synthesizes encoded patterns. FIG. [Figure 7]2 is a block diagram illustrating a schematic hardware configuration of the image forming apparatus in FIG. 1. [Figure 8] 8 is a flowchart showing a procedure of a control process executed in a controller of FIG. 7. [Figure 9] 3A and 3B are diagrams showing halftone patterns that can be used by the image forming apparatus of FIG. 1. [Figure 10] FIG. 13 is a diagram for explaining reproducibility of an encoding pattern. [Figure 11] FIG. 10 is a diagram showing an example of a coding pattern uniformity table generated in step S812 of FIG. 8. [Figure 12] 2 is a block diagram illustrating a schematic hardware configuration of the additional information extraction device of FIG. 1. [Figure 13] 2 is a flowchart showing the procedure of additional information extraction processing executed in the additional information extraction device of FIG. [Figure 14] 10 is a schematic diagram showing a difference in frequency characteristics in a two-dimensional frequency domain in the Y plane of the present embodiment. FIG. [Figure 15] FIG. 1 is a diagram illustrating an example of an HPF having a specific frequency vector directionality. [Figure 16] FIG. 14 is a diagram for explaining detection of multiplexed blocks in step S1302 of FIG. [Figure 17] FIG. 13 is a diagram showing an example of a printed matter on which additional information is multiplexed. [Figure 18] 2 is a flowchart showing the procedure of a PDL data transmission process executed in the host PC of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the embodiments are essential to the solution of the present invention. Note that the same components are given the same reference numbers and descriptions are omitted.

[0011] FIG. 1 is a diagram for explaining multiplexing of additional information and extraction of additional information in this embodiment.

[0012] In this embodiment, multiplexing of additional information is performed by a host PC 100, an additional information multiplexing device 101, and an image forming device 102 shown in FIG.

[0013] The host PC 100 converts image and document data into PDL data using a printer driver 212 (described later in FIG. 2) and transmits this PDL data to the additional information multiplexing device 101 via a network 240 (described later in FIG. 2). Note that PDL is an abbreviation for Page DeScription Language. The PDL data includes ON / OFF information for the multiplexing function, additional information, etc.

[0014] The additional information multiplexing device 101 rasterizes the PDL data received from the host PC 100. For example, when the multiplexing function is OFF, the additional information multiplexing device 101 transmits image data obtained by rasterization to the image forming device 102 via a network 240, which will be described later. On the other hand, when the multiplexing function is ON, the additional information multiplexing device 101 encodes the additional information into binary data represented by binary numbers, and converts this binary data into an encoding pattern. The additional information multiplexing device 101 also combines this encoding pattern with the image data obtained by rasterization. The additional information multiplexing device 101 transmits the image data combined with the encoding pattern to the image forming device 102 via the network 240, which will be described later. Details of the processing by the additional information multiplexing device 101 will be described later.

[0015] The image forming apparatus 102 converts the received image data into image data for printing, and performs printing processing based on this image data for printing, thereby generating a printed matter on which additional information is multiplexed.

[0016] In this embodiment, the extraction of additional information is performed by an additional information extraction device 103 shown in FIG. 1(b).

[0017] The additional information extraction device 103 reads a printed matter and generates scanned image data of the printed matter, or receives image data obtained by photographing the printed matter via a network 240, which will be described later. If additional information is multiplexed in the image data, the additional information extraction device 103 extracts a coding pattern. In addition, the additional information extraction device 103 converts the extracted coding pattern into binary data represented by binary numbers, and decodes this binary data into the original additional information. In this way, the additional information can be extracted from the printed matter on which the additional information is multiplexed.

[0018] Next, the host PC 100 in this embodiment will be described.

[0019] Fig. 2 is a block diagram showing a schematic hardware configuration of the host PC 100 in Fig. 1. In Fig. 2, the host PC 100 includes a CPU 201, a ROM 202, a RAM 203, a network I / F 204, an auxiliary storage device 210, and an input / output I / F 220. These are connected to each other via an internal bus 200.

[0020] The CPU 201 controls the entire host PC 100 in accordance with programs stored in the ROM 202, RAM 203, and auxiliary storage device 210. The ROM 202 stores various programs. The RAM 203 is used as a work area when the CPU 201 performs various processes. The auxiliary storage device 210 stores an application 211, a printer driver 212, an operating system (OS) 213, and the like.

[0021] The network I / F 204 is an interface for the host PC 100 to transmit and receive data to and from an external device connected to the network 240, for example, the additional information multiplexing device 101. The input / output I / F 220 is connected to an input / output device 230. The input / output device 230 is, for example, a keyboard 231, a pointing device 232, a camera 233, a microphone 234, and a monitor 235. The keyboard 231 and the pointing device 232 are input devices for a user to input various instructions to the host PC 100. The camera 233 has a photographing function. The microphone 234 has a sound collecting function. Note that in a configuration in which the host PC 100 has a photographing function and a sound collecting function, the camera 233 and the microphone 234 do not need to be connected to the input / output I / F 220. The monitor 235 displays various screens based on display data acquired from the input / output I / F 220.

[0022] Here, the operation of the printer driver 212 will be described. When the printer driver 212 receives a print instruction from the OS 213, it displays the print setting screen of the printer driver 212 on the monitor 235. The printer driver 212 saves the print setting information input by the user in the RAM 203. The print setting information includes, for example, ON / OFF information of the multiplexing function, additional information, color component information of the coding pattern, image processing settings to be described later, and the like. The color component information of the coding pattern is information indicating the color planes to be combined with the coding pattern. In addition, the printer driver 212 generates PDL data according to a GDI command provided by the OS 213, and saves this PDL data in the RAM 203. The generated PDL data is transmitted to the additional information multiplexing device 101 via the network I / F 204.

[0023] Next, the additional information multiplexing device 101 according to this embodiment will be described.

[0024] Fig. 3 is a block diagram showing a schematic hardware configuration of the additional information multiplexing device 101 in Fig. 1. The additional information multiplexing device 101 includes a CPU 301, a RAM 302, a ROM 303, and a network I / F 304. These are connected to each other via an internal bus 305.

[0025] The CPU 301 controls the entire additional information multiplexing device 101. The RAM 302 is used as a work area when the CPU 301 executes various commands. The ROM 303 stores programs executed by the CPU 301 when the additional information multiplexing device 101 is started up, setting data for the additional information multiplexing device 101, and the like. The network I / F unit 304 is an interface that enables the additional information multiplexing device 101 to transmit and receive data to and from external devices connected to the network 240, such as the host PC 100 and the image forming device 102. For example, when the additional information multiplexing device 101 receives PDL data from the host PC 100, it stores the PDL data in the RAM 302 and executes the image data generation process of FIG. 4.

[0026] Fig. 4 is a flowchart showing the procedure of the multiplexing control process executed in the additional information multiplexing device 101 of Fig. 1. The multiplexing control process of Fig. 4 is realized by the CPU 301 executing a program stored in the ROM 303. Fig. 4(a) shows the procedure of the entire multiplexing control process.

[0027] In FIG. 4(a), first, the CPU 301 analyzes the PDL data read from the RAM 302 (step S401). The CPU 301 generates image data and attribute data in a bitmap format. The image data in the bitmap format is image data in an RGB color space (hereinafter referred to as "RGB image data"). The attribute data is data generated for each pixel based on the type of drawing command of the object. The attribute data is determined according to the following criteria. Specifically, the attribute data of pixels in an area specified by a character drawing command (character type and character code) is determined to be character attributes. The attribute data of pixels in an area specified by a line drawing command (coordinate points, length, thickness) is determined to be line attributes. The attribute data of pixels in an area specified by a figure drawing command (rectangle, shape, coordinate points) is determined to be figure attributes. The attribute data of pixels in an area specified by an image drawing command (a set of points) is determined to be image attributes. The CPU 301 also obtains print setting information from the PDL data and stores this print setting information in the RAM 302. As described above, the print setting information includes ON / OFF information of the multiplexing function, additional information, color component information of the coding pattern, image processing settings, etc. The image processing settings are, for example, information indicating a halftone pattern used in halftone processing described later. This halftone pattern is, for example, a halftone pattern specified by a user who instructed the host PC 100 to transmit PDL data, or a default halftone pattern.

[0028] Next, CPU 301 performs color space conversion to convert the generated RGB image data into image data in the CMYK color space (hereinafter referred to as "CMYK image data") (step S402). In this color space conversion, a four-dimensional LUT is used that can convert the RGB image data into a CMYK color space that can form desired color (Lab) values ​​on paper. This four-dimensional LUT may be one that has been obtained in advance through experiments or simulations, or may be one that has been calculated using a formula or the like. The CMYK image data obtained in step S402 is stored in RAM 302.

[0029] Next, CPU 301 determines whether the multiplexing function is ON based on ON / OFF information of the multiplexing function included in the print setting information stored in RAM 302 (step S403). If it is determined in step S403 that the multiplexing function is ON, CPU 301 acquires additional information from RAM 302 (step S404). Next, CPU 301 performs the additional information multiplexing process of FIG. 4B (step S405).

[0030] FIG. 4B is a flow chart showing the procedure of the additional information multiplexing process in step S405 of FIG.

[0031] In FIG. 4B, the CPU 301 performs encoding processing on the acquired additional information (step S411). In the encoding processing, the numbers and characters indicated by the additional information are converted into binary data, which is binary data represented only by "0" and "1", based on a character code. The character code defines information indicating what binary data the numbers and characters are converted into. Here, as an example, a case will be described where encoding processing is performed on the additional information "hello" based on the character code "Shift JIS". In this case, the additional information "hello" is converted into binary data "0110100001100101011011000110110001101111".

[0032] Next, CPU 301 converts the binary data obtained in step S411 into a coding pattern for each numerical value ("0" or "1") constituting the binary data (step S412). Here, the coding pattern to be combined with the image data will be explained with reference to FIG. 5. FIG. 5(a) is a coding pattern composed of 10px (pixels) x 10px corresponding to the numerical value "0". FIG. 5(b) is a coding pattern composed of 10px x 10px corresponding to the numerical value "1".

[0033] By synthesizing the coding pattern in FIG. 5(a) and the coding pattern in FIG. 5(b) with image data, the image data will have different periodicities in units of 10px x 10px blocks. The method of synthesizing coding patterns will be described later. When a printed matter is generated by printing the image data with such a coding pattern synthesized, if the image data obtained by reading the printed matter can be subjected to frequency analysis to identify the arrangement of the coding patterns with two periodicities, binary data consisting of "0" and "1" can be read.

[0034] Next, the CPU 301 acquires the CMYK image data obtained in step S402 and the color component information of the coding pattern included in the print setting information from the RAM 302. The CPU 301 sets the position coordinates of the blocks to be combined with each coding pattern for the image of the color plane indicated by the color component information of the coding pattern in the CMYK image data (step S414). For example, the image size is 640px vertical and 480px horizontal. The block size is the size of the coding pattern, that is, 10px vertical and 10px horizontal. In this case, the number of vertical blocks is 640÷10=64 blocks, and the number of horizontal blocks is 480÷10=48 blocks. The total number of blocks is 64×48=3072 blocks. In step S414, for example, the upper left coordinates of the target block are set as the position coordinates of the block.

[0035] Here, the size of the additional information that can be expressed will be described. The additional information multiplexing device 101 multiplexes the same data in multiple locations so that the additional information extraction device 103 can extract the additional information even if only a part of the printed matter is read. For example, if the same additional information is multiplexed in 32 locations, and the total number of blocks in the image is 3072 as found in step S414, the size of the additional information is such that it can be expressed using 3072÷32=96 blocks. Since one block is 1-bit information of "0" and "1", the additional information can handle 96-bit information. However, in Shift JIS, 8 bits of "11111111", which are not expressed as characters, are included at the beginning of the character so that the starting position of the 96 bits can be known. Therefore, it is possible to define 96-8=88-bit data as the additional information. In this embodiment, in step S411, binary data that fits within 88 bits and is made up of "0" and "1" is obtained.

[0036] Next, the CPU 301 synthesizes each coding pattern obtained in step S412 with the CMYK image data obtained in step S402 at the position coordinates of each block set in step S414 (step S415). Here, a method of calculating pixel values ​​when synthesizing coding patterns will be described with reference to FIG. 6. In this embodiment, a case will be described in which a print instruction is given to synthesize the coding pattern on a Yellow plane (hereinafter referred to as "Y plane") having a high lightness component in the CMYK color space so that the coding pattern is not noticeable. FIG. 6(a) corresponds to the coding pattern in FIG. 5(a), and FIG. 6(b) corresponds to the coding pattern in FIG. 5(b). The numerical values ​​in the diagram indicate the pixel values ​​of Yellow to be added to the CMYK image data obtained in step S402. For example, if the pixel values ​​of the Y plane to which the coding pattern in FIG. 6 is synthesized are all 20, the pixel with a numerical value of 0 in FIG. 6 will be 20+0=20, and the pixel with a numerical value of 72 in FIG. 6 will be 20+72=92. If the pixel value of the Y plane of the block to which the coding pattern is to be synthesized is 184 or more, the result will be 184+72=256, which exceeds the 8-bit maximum value. In such a case, the pixel value is clipped to the 8-bit maximum value of 255. By synthesizing the coding pattern in this way, the Y plane will have a predetermined period due to the coding pattern in units of 10 pix x 10 pix blocks. The CMYK image data with which the coding pattern has been synthesized is stored in the RAM 302, and the multiplexing control process ends. After that, this CMYK image data and image processing settings are transmitted to the image forming apparatus 102.

[0037] On the other hand, if it is determined in step S403 that the multiplexing function is not ON but OFF, the multiplexing control process ends. After that, the CMYK image data and image processing settings stored in the RAM 302 are transmitted to the image forming apparatus 102.

[0038] In the present embodiment, the configuration has been described in which the additional information acquired from the PDL data is converted into a coding pattern and the coding pattern is synthesized with the CMYK image data, but the present invention is not limited to this configuration. For example, instead of the additional information acquired from the PDL data, additional information previously stored in the ROM 303 of the additional information multiplexing device 101 may be converted into a coding pattern and the coding pattern may be synthesized with the CMYK image data.

[0039] Next, the image forming apparatus 102 according to the present embodiment will be described.

[0040] Fig. 7 is a block diagram showing a schematic hardware configuration of the image forming apparatus 102 in Fig. 1. In Fig. 7, the image forming apparatus 102 includes a controller 700, a UI 720, a scanner 730, and a printer 740. The controller 700 is connected to the UI 720, the scanner 730, and the printer 740. The controller 700 also includes a network I / F 701, a CPU 702, a RAM 703, a ROM 704, a printer image processing unit 705, an engine I / F 706, and an input / output I / F 707. These are connected to each other via an internal bus 708.

[0041] The network I / F 701 is an interface through which the image forming apparatus 102 transmits and receives data to and from an external device connected to the network 240, such as the additional information multiplexing device 101. The CPU 702 controls the entire image forming apparatus 102. The RAM 703 is used as a work area when the CPU 702 executes various commands. The ROM 704 stores programs executed by the CPU 702 when the image forming apparatus 102 is started up, setting data for the controller 700, and the like. The printer image processing unit 705 converts image data and document data received from an external device into print data. The engine I / F 706 transfers this print data to the printer 740. The input / output I / F 707 is an interface through which the controller 700 transmits and receives data to and from the UI 720 and the scanner 730.

[0042] The printer 740 prints an image on paper based on the print data. The UI 720 is a user interface that allows the user to give instructions such as selecting paper information to the image forming apparatus 102. The scanner 730 reads a printed material and generates image data of the printed material.

[0043] Here, an overview of the operation of the controller 700 will be described.

[0044] Fig. 8 is a flowchart showing the procedure of the control process executed in the controller 700 of Fig. 7. Fig. 8(a) shows the procedure of the entire control process. This control process is realized by the CPU 702 of the controller 700 executing a program stored in the ROM 704. This control process is executed when the additional information multiplexing device 101 executes a multiplexing control process to generate CMYK image data and transmits this CMYK image data and image processing settings to the image forming device 102.

[0045] 8A, first, the CPU 702 acquires CMYK image data and image processing settings from the additional information multiplexing device 101 via the network I / F 701 (step S801). As described above, the image processing settings are information indicating the halftone pattern used in the halftone process.

[0046] Here, a case where the user switches the halftone pattern will be described First, halftone pattern candidates in this embodiment will be described with reference to FIG.

[0047] Fig. 9 is a diagram showing halftone patterns that can be used by the image forming apparatus 102 in Fig. 1. In Fig. 9, halftone pattern 1 is a halftone pattern with a low screen ruling, halftone pattern 2 is a halftone pattern with a high screen ruling, and halftone pattern 3 is a halftone pattern with a higher screen ruling than halftone pattern 2. The image forming apparatus 102 can switch between these three halftone patterns. In this embodiment, halftone pattern 1 is the default halftone pattern with a low screen ruling, and halftone pattern 2 is the default halftone pattern with a high screen ruling.

[0048] In the dithering method using a threshold matrix, the higher the number of lines, the more small dots the image data after halftone processing is composed of. This improves the reproducibility of small points and characters with low signal values, but the reproducibility of the dots themselves becomes unstable and the gradation of the image area decreases.

[0049] On the other hand, in the dithering method using a threshold matrix, the lower the number of lines, the fewer the number of large dots the image data after halftone processing is composed of. Therefore, the reproducibility of small points and characters with low signal values ​​decreases (increased jaggedness, etc.), but the reproducibility of the dots themselves is stable and the gradation of gradations and the like is improved. In this way, there is a trade-off between low line count and high line count. The image forming device 102 obtains the attribute data obtained in step S401 from the additional information multiplexing device 101 and performs halftone processing based on this attribute data. For example, the image forming device 102 performs halftone processing by the dithering method with a low line count threshold matrix on the image attribute region in the image data. Also, the image forming device 102 performs halftone processing by the dithering method with a high line count threshold matrix on the character attribute region, line attribute region, and graphic attribute region in the image data. By controlling the halftone processing according to the attribute in this way, the trade-off relationship of the line count is eliminated, and it is possible to output a printed matter of good image quality for each attribute.

[0050] For example, a user may be more concerned about jaggy characteristics than gradation and may select halftone pattern 2, which has a higher screen ruling than halftone pattern 1, as the default halftone pattern for the image part. Anticipating such user requests, the image forming apparatus 102 holds a plurality of halftone patterns. Note that, for ease of explanation, the following describes a case where halftone patterns are not switched for each attribute, but only a default halftone pattern with a low screen ruling is used. In other words, in this embodiment, it is assumed that halftone pattern 1, which is the default halftone pattern with a low screen ruling, is set as the halftone pattern used in halftone processing.

[0051] Returning to the explanation of FIG. 8(a), the CPU 702 acquires ON / OFF information of the multiplexing function from the additional information multiplexing device 101 via the network I / F 701. Next, the CPU 702 determines whether the multiplexing function is ON or not based on the acquired ON / OFF information of the multiplexing function (step S802). If it is determined in step S802 that the multiplexing function is OFF, not ON, the process proceeds to step S806, which will be described later. If it is determined in step S802 that the multiplexing function is ON, the CPU 702 performs the coding pattern uniformity determination process of FIG. 8(b) (step S803).

[0052] However, when halftoning is performed on image data with a coded pattern combined therewith, the coded pattern may not be reproduced uniformly. Here, a case where the coded pattern cannot be reproduced uniformly will be described with reference to FIG.

[0053] Fig. 10(a) shows an example in which the coding patterns of Fig. 5(a) and Fig. 5(b) are combined with the Y plane of CMYK image data. Fig. 10(b) shows the threshold matrix for Yellow in halftone pattern 1. Fig. 10(c) shows the result of halftone processing of the image data of Fig. 10(a) using the threshold matrix of Fig. 10(b).

[0054] In FIG. 10(a), 1001 and 1004 are obtained by combining the coding pattern in FIG. 5(a) with a signal value of 72, and 1002 and 1003 are obtained by combining the coding pattern in FIG. 5(b) with a signal value of 72. The image data combined with the coding pattern in this way is subjected to halftone processing using the yellow threshold matrix of halftone pattern 1 shown in FIG. 10(b). Note that the 134 lpi, 117 deg line screen shown in FIG. 9 is used by default for the Y plane of halftone pattern 1. Through the above halftone processing, the image data shown in FIG. 10(a) becomes the binary image shown in FIG. 10(c).

[0055] In 1006 and 1007 in FIG. 10(c), even if the coded patterns are binary-coded by the halftone process, dots corresponding to the coded patterns still exist, so that the periodicity of the coded patterns can be maintained on the paper even if the coded patterns are printed as is. On the other hand, in 1005 and 1008 in FIG. 10(c), dots corresponding to the coded patterns do not exist and disappear due to the halftone process, so that additional information cannot be extracted from the printout obtained by the printing process of such image data. This is because the angle of the coded pattern matches the screen angle of the Y plane of the halftone pattern 1 used in the halftone process, and binary dots are not formed due to the threshold arrangement or initial phase of the screen matrix. Specifically, the dashed line parts of 1001 and 1004 are compared only with the parts with high thresholds in the screen matrix in FIG. 10(b), and as a result, binary dots are not formed. In this way, if the angle of the coded pattern matches the screen angle of the color plane with which the coded pattern is synthesized in the halftone pattern used in the halftone process, the coded pattern cannot be reproduced uniformly.

[0056] In contrast to this, in this embodiment, a coding pattern uniformity determination process is executed in step S803.

[0057] FIG. 8B is a flowchart showing the procedure of the coding pattern uniformity determination process in step S803 of FIG. 8A.

[0058] In Fig. 8(b), the CPU 702 acquires color component information of the coding pattern from the additional information multiplexing device 101 via the network I / F 701 (step S811). The color component information of the coding pattern is information indicating a color plane into which the coding pattern is synthesized in the CMYK image data. In this embodiment, information indicating the Y plane is acquired in step S811.

[0059] Next, the CPU 702 generates the coding pattern uniformity table 1101 of FIG. 11 (step S812). The coding pattern uniformity table 1101 is created based on a result of comparing the screen angle of each color plane in the halftone patterns 1 to 3 with the angle of the coding pattern synthesized with the CMYK image data. The coding pattern uniformity table 1101 includes uniformity reproduction possibility information for each of cyan, magenta, yellow, and black for the halftone patterns 1 to 3. The uniformity reproduction possibility information is information indicating whether all the coding patterns synthesized with the CMYK image data can be reproduced uniformly (◯) or not (×). In FIG. 11, for example, the uniformity reproduction possibility information for cyan and yellow in the halftone pattern 1, magenta in the halftone pattern 2, and magenta in the halftone pattern 3 is "×". This indicates that the coding patterns cannot be reproduced uniformly in the cyan and yellow in the halftone pattern 1, the magenta in the halftone pattern 2, and the magenta in the halftone pattern 3. In addition, in the coding pattern uniformity table 1101, even if the angle does not completely match the angle of the coding pattern combined with the CMYK image data, an "X" may be set as the uniformity reproducibility information for a color plane whose angle approximately matches the angle.

[0060] Next, the CPU 702 obtains, from the coding pattern uniformity table 1101, uniformity reproducibility information corresponding to the color plane indicated by the color component information of the coding pattern obtained in step S811 in the halftone pattern 1. The CPU 702 determines whether the obtained uniformity reproducibility information is "o" or not (step S813). If it is determined in step S813 that the obtained uniformity reproducibility information is "o", the process proceeds to step S814. If it is determined in step S813 that the obtained uniformity reproducibility information is "x" rather than "o", the process proceeds to step S815.

[0061] In step S814, the CPU 702 outputs Pattern_Uniformity_Flag=1 as a flag indicating that it has been determined that the coding pattern combined with the CMYK image data can be reproduced uniformly. Then, the coding pattern uniformity determination process ends, and the process proceeds to step S804.

[0062] In step S815, the CPU 702 outputs Pattern_Uniformity_Flag=0 as a flag indicating that it has been determined that the coding pattern combined with the CMYK image data cannot be reproduced uniformly. Then, the coding pattern uniformity determination process ends, and the process proceeds to step S804.

[0063] In step S804, the CPU 702 determines whether the Pattern_Uniformity_Flag is "1". If it is determined in step S804 that the Pattern_Uniformity_Flag is "1", the process proceeds to step S806. If it is determined in step S804 that the Pattern_Uniformity_Flag is "0" rather than "1", the process proceeds to step S805.

[0064] In step S805, the CPU 702 performs the halftone setting switching process of FIG.

[0065] FIG. 8C is a flow chart showing the procedure of the halftone setting switching process in step S805 of FIG. 8A.

[0066] 8(c), the CPU 702 selects halftone patterns to be switching candidates from the coding pattern uniformity table 1101 (step S821). In step S812, halftone patterns for which the uniformity reproducibility information of the Y plane, which is the color plane into which the coding pattern is synthesized, is set to "o" in the coding pattern uniformity table 1101, specifically, halftone patterns 2 and 3 are selected as switching candidates. Next, the CPU 702 determines whether or not there is only one switching candidate selected (step S822).

[0067] If it is determined in step S822 that only one switching candidate has been selected, the CPU 702 changes the halftone pattern used in the halftone process from halftone pattern 1 to the switching candidate selected in step S821 (step S823). Upon completion of the process of step S823, the halftone setting switching process ends, and the process proceeds to step S806 in FIG. 8(a).

[0068] If it is determined in step S822 that a plurality of switching candidates have been selected, rather than one, then the process proceeds to step S824, in which the CPU 702 changes the halftone pattern used in the halftone process from halftone pattern 1 to one halftone pattern selected from the switching candidates (step S824).

[0069] In step S824, for example, the halftone pattern with the highest number of lines is selected from among the switching candidates. This can improve the reproducibility of characters with small points or low signal values. In this embodiment, the selection of the halftone pattern to be switched to is not limited to this configuration. For example, the switching candidates may be displayed on the UI 720, and in step S824, the halftone pattern designated by the user on the UI 720 may be selected from the halftone pattern 1. Also, the priority order may be set in advance by the user for the halftone patterns 1 to 3, and the halftone pattern with the highest priority order may be selected from among the switching candidates. This makes it possible to generate image data that uniformly reproduces the encoding pattern while performing halftone processing using the halftone pattern preferred by the user. When the processing of step S824 is completed, the halftone setting switching processing ends, and the processing proceeds to step S806 in FIG. 8(a).

[0070] In step S806, the CPU 702 executes the printer image processing of FIG.

[0071] FIG. 8D is a flow chart showing the procedure of the printer image processing in step S806 in FIG.

[0072] 8D, the CPU 702 performs gamma correction processing on the CMYK image data acquired in step S801 (step S831). This gamma correction processing is performed using a one-dimensional LUT so that the image data obtained by halftone processing in step S832, which will be described later, has desired density characteristics when transferred to recording paper. The image data that has undergone gamma correction processing is stored in the RAM 703.

[0073] Next, the CPU 702 performs halftone processing on the gamma-corrected image data stored in the RAM 703 (step S832). This halftone processing uses the halftone pattern set up to step S806. That is, when synthesizing an encoding pattern, a halftone pattern capable of uniformly reproducing the encoding pattern is used. The halftone-processed image data is stored in the RAM 703, and this control process ends. Thereafter, the printer 740 forms the halftone-processed image data stored in the RAM 703 on paper. This produces a printed matter. For example, if the multiplexing function is ON, a printed matter is produced on which additional information is multiplexed.

[0074] In the present embodiment, the image forming apparatus 102 generates the coding pattern uniformity table 1101 in step S812, but the present invention is not limited to this configuration. For example, another device such as the host PC 100 or the additional information multiplexing device 101 may generate the coding pattern uniformity table 1101. In such a configuration, the image forming apparatus 102 acquires the coding pattern uniformity table 1101 from the other device in step S812, and performs the process of step S813 using the acquired coding pattern uniformity table 1101.

[0075] Next, the additional information extraction device 103 in this embodiment will be described.

[0076] Fig. 12 is a block diagram showing a schematic hardware configuration of the additional information extraction device 103 of Fig. 1. In Fig. 12, the additional information extraction device 103 includes an additional information extraction control unit 1200, a UI 1210, and an image reading unit 1220. The additional information extraction control unit 1200 is connected to the UI 1210 and the image reading unit 1220. The additional information extraction control unit 1200 also includes a network I / F 1201, a CPU 1202, a RAM 1203, and a ROM 1204. These are connected to each other via an internal bus 1205.

[0077] The additional information extraction control unit 1200 extracts additional information from the scan image data generated by the image reading unit 1220 by reading the printed matter. The network I / F 1201 is an interface for the additional information extraction device 103 to transmit and receive data to and from an external device connected to the network 240. The CPU 1202 controls the entire additional information extraction device 103. The RAM 1203 is used as a work area when the CPU 1202 executes various commands. The ROM 1204 stores programs executed by the CPU 1202 when the additional information extraction device 103 is started, setting data of the additional information extraction control unit 1200, and the like. The UI 1210 is a user interface for the user to operate the additional information extraction device 103. The image reading unit 1220 has a scan function. For example, when the user inputs an instruction to read additional information multiplexed on the printed matter to the UI 1210, the image reading unit 1220 reads the set printed matter and generates scan image data of the printed matter. The generated scanned image data is stored in the RAM 1203, and the additional information extraction process of FIG. 13 is executed.

[0078] Fig. 13 is a flowchart showing the procedure of the additional information extraction process executed in the additional information extraction device 103 of Fig. 1. This additional information extraction process is realized by the CPU 1202 executing a program stored in the ROM 1204.

[0079] 13, the CPU 1202 acquires the scan image data generated by the image reading unit 1220 from the RAM 1203 (step S1301). Next, the CPU 1202 detects the position of a multiplexed block corresponding to a block of a coding pattern combined with the acquired scan image (step S1302). Here, a method of detecting the position of a multiplexed block will be described with reference to FIGS. 14, 15, and 16.

[0080] 14 is a schematic diagram showing the difference in frequency characteristics in the two-dimensional frequency domain in the Y plane of the present embodiment. The horizontal axis indicates the frequency in the horizontal direction, and the vertical axis indicates the frequency in the vertical direction. The origin in the center indicates a direct current component, and the frequency range increases as the frequency moves away from the origin.

[0081] 14, the area where the power of frequency components at 117 deg and 297 deg appears is indicated by a straight line 1401, and the area where the power of frequency components at 27 deg and 206 deg appears is indicated by a straight line 1402. Furthermore, the area where the power of frequency components at 134 lpi appears is indicated by a circular line 1403. In other words, an intersection 1411 of the straight line 1401 and the circular line 1403 indicates the location where the power of frequency components at 134 lpi and 117 deg appears, and an intersection 1412 of the straight line 1401 and the circular line 1403 indicates the location where the power of frequency components at 134 lpi and 297 deg appears. An intersection 1413 between the line 1402 and the circle 1403 indicates the location where the power of the frequency component at 134 lpi and 27 deg appears, and an intersection 1414 between the line 1402 and the circle 1403 indicates the location where the power of the frequency component at 134 lpi and 206 deg appears.

[0082] For example, when the frequency components of the coding pattern in Fig. 5(a) are 134 lpi and 117 deg, a large power spectrum occurs at the intersection 1411. When the frequency components of the coding pattern in Fig. 5(b) are 134 lpi and 27 deg, a large power spectrum occurs at the intersection 1413. By detecting the location where a power spectrum above a certain threshold occurs in this way, it is possible to determine which coding patterns are being combined.

[0083] For example, when the halftone pattern is changed to 300 lpi, 0 deg, which can uniformly reproduce the coding pattern in step S805 described above, the frequency component of the Y plane generated by the halftone process appears at point 1415. 300 lpi, 0 deg is a halftone pattern that can uniformly reproduce the coding patterns of FIG. 5(a) and FIG. 5(b). Therefore, when frequency analysis is performed on the scanned image data in which these coding patterns are uniformly reproduced, a large power spectrum appears at intersection 1411 and intersection 1413. On the other hand, when a halftone pattern that cannot uniformly reproduce the coding pattern, for example, a halftone pattern of 134 lpi, 117 deg, is used as it is, the coding pattern of FIG. 5(a) disappears as shown in FIG. 11(c). Therefore, the large power spectrum that should have appeared at intersection 1411 does not appear, and the coding pattern cannot be detected.

[0084] Figures 15(a) and 15(b) are diagrams showing an example of an HPF (high-pass filter) having a specific frequency vector directionality. The HPFs in Figures 15(a) and 15(b) are also used as spatial filters when detecting frequency vectors. That is, the spatial filter in Figure 15(a) can emphasize frequency vectors on a straight line 1401, and the spatial filter in Figure 15(b) can emphasize frequency vectors on a straight line 1402.

[0085] As an example, a case will be described in which a large power spectrum occurs on the frequency vector of the line 1401 in Fig. 14 due to the encoding pattern in Fig. 5(a). In this case, the spatial filter in Fig. 15(a) amplifies the amount of change in the power spectrum, but the spatial filter in Fig. 15(b) hardly amplifies the amount of change in the power spectrum. In other words, when multiple spatial filters are filtered in parallel, amplification occurs only when the spatial filter with the same frequency vector is used, and amplification hardly occurs in other filters. Therefore, it is easy to determine on which frequency vector a large power spectrum occurs.

[0086] As described above, by determining the frequency characteristics, it is possible to extract the coding pattern, but if the position to be extracted is shifted when determining the frequency characteristics, the coding pattern cannot be extracted correctly. For this reason, in this embodiment, in step S1302, the position of the multiplexed block in the acquired scanned image is detected.

[0087] FIG. 16 is a diagram for explaining the detection of the multiplexed block in step S1302 in FIG. 13. An image 1601 shows a part of the scanned image, specifically, an image composed of four blocks of the coding pattern. Regions 1602 and 1603 show the regions to be determined for the frequency characteristics. FIG. 16(a) shows a state in which the determination region 1602 is shifted from the position of the block of the coding pattern. FIG. 16(b) shows a state in which the determination region 1603 coincides with the position of the block of the coding pattern. When the determination region 1603 coincides with the position of the block of the coding pattern as in FIG. 16(b), it is possible to correctly identify the predetermined frequency. On the other hand, when the determination region 1602 is shifted from the position of the block of the coding pattern as in FIG. 16(a), the power spectrum of the specific frequency vector is lowered, making it difficult to identify the predetermined frequency. The CPU 1202 detects the position of the multiplexed block corresponding to the block of the coding pattern based on whether the power spectrum of the specific frequency vector is strong or weak. Therefore, the CPU 1202 detects multiplexed blocks by determining frequency characteristics while shifting the position of the block for the acquired scan image data. This is the method for detecting multiplexed blocks.

[0088] Returning to FIG. 13, the CPU 1202 determines whether the position of the multiplexed block has been detected (step S1303). If it is determined in step S1303 that the position of the multiplexed block has not been detected, the additional information extraction process ends. If it is determined in step S1303 that the position of the multiplexed block has been detected, the CPU 1202 uses the detected position as a reference and extracts the synthesized coding pattern using the determination result of the frequency characteristics (step S1304).

[0089] FIG. 17 is a diagram showing an example of a printed matter 1701 on which additional information is multiplexed. In FIG. 17, a block 1702 indicates a multiplexed block. The number of multiplexed blocks is 48 blocks horizontally and 96 blocks vertically, totaling 3072 blocks. In FIG. 17, the additional information is encoded to "0" and "1" for each block and synthesized as an encoding pattern. In step S1304, the position is shifted by 3072 blocks in block units based on the position detected in step S1302, and frequency characteristics are determined. In this case, one encoding pattern can be determined for each block, so that a total of 96 bits x 32 bits of data can be extracted. In this way, by determining frequency characteristics while shifting the position, all encoding patterns can be extracted. However, in this embodiment, as described above, 32 pieces of the same data are synthesized, so the size of the additional information itself is 88 bits, excluding "11111111" which indicates the start.

[0090] Next, the CPU 1202 analyzes the extracted coding patterns and decodes them into the format of the original additional information (step S1305). Specifically, the CPU 1202 converts the extracted coding patterns into binary data represented by binary numbers, and decodes this binary data into the original additional information based on the character code. The author can be identified by comparing the decoded additional information with correct answer data stored in an external server, for example. When the process of step S1305 is completed, the additional information extraction process ends.

[0091] According to the above-described embodiment, when it is determined that the coding pattern cannot be uniformly reproduced, the halftone pattern used in the halftone process is changed to another halftone pattern. The other halftone pattern is a halftone pattern that is determined to be capable of uniformly reproducing the coding pattern in the color plane into which the coding pattern is synthesized when used in the halftone process. This makes it possible to select an appropriate halftone pattern according to the color component into which the coding pattern is synthesized.

[0092] In the above-described embodiment, the other halftone patterns are halftone patterns in which the screen angle of the color plane into which the coding pattern is synthesized does not match the angle of the coding pattern, thereby making it possible to select a halftone pattern that can uniformly reproduce the coding pattern according to the color component into which the coding pattern is synthesized.

[0093] The image processing device according to the present embodiment is an image forming device 102 that performs halftone processing using a set halftone pattern and prints a printed matter on which additional information is multiplexed. This makes it possible to select an appropriate halftone pattern according to the color components to be combined with the coding pattern when performing halftone processing.

[0094] In the above-mentioned embodiment, the additional information multiplexing device 101 synthesizes the code patterns, and the additional information extraction device 103 extracts the additional information. However, the present invention is not limited to this configuration. For example, the image forming device 102 may synthesize the code patterns and extract the additional information. When the image forming device 102 synthesizes the code patterns and extracts the additional information, the host PC 100 transmits the PDL data to the image forming device 102, and the image forming device 102 encodes the additional information and performs a printing process of the image data synthesized with the coding pattern. At this time, the coding pattern uniformity determination process and the halftone setting switching process are performed by the image forming device 102. In addition, in the extraction of the additional information, the scanner 730 of the image forming device 102 reads the printed matter and generates the scan image data of the printed matter, and the image forming device 102 performs the above-mentioned additional information extraction process based on the scan image data.

[0095] Furthermore, in this embodiment, if the host PC 100 holds information on the coding pattern and information on the halftone pattern, the host PC 100 may execute the coding pattern uniformity determination process and halftone setting switching process described above.

[0096] Fig. 18 is a flowchart showing the procedure of the PDL data transmission process executed in the host PC 100 of Fig. 1. The PDL data transmission process is realized by the CPU 201 executing a program stored in the ROM 202. The PDL data transmission process is executed when the host PC 100 receives an instruction to print an image / document from a user.

[0097] 18, first, the CPU 201 acquires the print setting information inputted as the print instruction by the user using the keyboard 231 (step S1801). As described above, the print setting information includes ON / OFF information of the multiplexing function, additional information, color component information of the coding pattern, image processing settings, etc.

[0098] Next, CPU 201 determines whether the multiplexing function is set to ON based on the acquired print setting information (step S1802). If it is determined in step S1802 that the multiplexing function is set to OFF, not ON, the process proceeds to step S1806, which will be described later. If it is determined in step S1802 that the multiplexing function is set to ON, the process proceeds to step S1803.

[0099] In step S1803, the CPU 201 performs coding pattern uniformity determination processing (step S1803). The coding pattern uniformity determination processing in step S1803 is the same processing as the coding pattern uniformity determination processing in step S803. Note that information used in the coding pattern uniformity determination processing, specifically, information indicating halftone patterns usable by the image forming apparatus 102 shown in Fig. 9, is acquired by the host PC 100 from the image forming apparatus 102 via the network 240. Alternatively, it is acquired when the printer driver is installed.

[0100] Next, CPU 201 determines whether Pattern_Uniformity_Flag is "1" (step S1804). If it is determined in step S1804 that Pattern_Uniformity_Flag is "1", the process proceeds to step S1806, which will be described later. If it is determined in step S1804 that Pattern_Uniformity_Flag is "0" rather than "1", the process proceeds to step S1805.

[0101] In step S1805, the CPU 201 performs halftone setting switching processing (step S1805). The halftone setting switching processing in step S1805 is the same processing as the halftone setting switching processing in step S805. Next, the CPU 201 converts the image data and the image processing settings into PDL data (step S1806). Here, the image processing settings include information indicating a halftone pattern used in the halftone processing, and if the multiplexing function is ON, this halftone pattern is changed in step S1805 to a halftone pattern that can uniformly reproduce the encoding pattern. Next, the CPU 201 transmits the PDL data to the additional information multiplexing device 101 via the network 240 (step S1807), and ends this processing.

[0102] In this manner, the image processing device according to the present embodiment is a host PC 100 (information processing device) that generates PDL data for causing an image forming device to print a printed matter in which additional information is embedded. This makes it possible to generate PDL data that specifies an appropriate halftone pattern according to the color components to be combined with the coding pattern.

[0103] In the present embodiment, the halftone pattern used in the halftone process is changed to another halftone pattern when it is determined that the coding pattern cannot be reproduced uniformly. However, the present invention is not limited to this configuration. For example, the color plane to be synthesized with the coding pattern may be changed to another color plane in the same halftone pattern that is determined to be capable of uniformly reproducing the coding pattern when used in the halftone process. As an example, a case will be described in which the halftone pattern 1 is set as the halftone pattern to be used in the halftone process, and the color plane to be synthesized with the coding pattern is Yellow. In this case, the color plane to be synthesized with the coding pattern is changed to Magenta, which is a color plane that is determined to be capable of uniformly reproducing the coding pattern when used in the halftone process in the halftone pattern 1, based on the coding pattern uniformity table 1101. This allows the coding pattern to be reproduced uniformly even when halftone process is performed on the image data synthesized with the coding pattern.

[0104] The present invention can also be realized by supplying a program that realizes one or more functions of the above-mentioned embodiments to a system or device via a network or a storage medium, and having one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0105] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) An image processing device that performs image processing for printing a printed material with embedded additional information, comprising: a setting means for setting a halftone pattern to be used in the halftone processing from among a plurality of halftone patterns; and a judgment means for judging whether the coding pattern generated based on the additional information can be uniformly reproduced in a color plane into which a coding pattern is synthesized when the set halftone pattern is used in the halftone processing, and when the judgment means judges that the coding pattern cannot be uniformly reproduced, the setting means changes the halftone pattern to be used in the halftone processing to another halftone pattern that is judged to be able to uniformly reproduce the coding pattern in the color plane into which the coding pattern is synthesized when used in the halftone processing. (Configuration 2) In the case where there are a plurality of halftone patterns that are determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing, the setting means changes the halftone pattern to be used in the halftone processing to another halftone pattern having the highest number of lines among the plurality of halftone patterns that are determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing. (Configuration 3) The image processing device according to Configuration 1, further comprising a display means, and a means for causing the display means to display a selection screen for allowing a user to select a halftone pattern to be used in the halftone processing from among a plurality of halftone patterns determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing, when there are a plurality of halftone patterns determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing. (Configuration 4) The image processing device according to configuration 1, characterized in that a priority order is preset for each of the plurality of halftone patterns, and when there are a plurality of halftone patterns that are determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing, the setting means changes the halftone pattern to be used in the halftone processing to another halftone pattern having the highest priority among the plurality of halftone patterns that are determined to be capable of uniformly reproducing the encoding pattern in the color plane into which the encoding pattern is synthesized when used in the halftone processing. (Configuration 5) An image processing device according to any one of configurations 1 to 4, characterized in that the other halftone pattern is a halftone pattern in which the screen angle of a color plane into which the encoding pattern is synthesized does not match the angle of the encoding pattern. (Configuration 6) The image processing device according to any one of configurations 1 to 5, characterized in that the image processing device is an image forming device that performs the halftone processing using the halftone pattern set by the setting means, and prints a printed matter in which the additional information is embedded. (Configuration 7) The image processing device according to any one of configurations 1 to 5, which is an information processing device that generates PDL data for causing an image forming device to print a printed matter in which the additional information is embedded. [Explanation of symbols]

[0106] 100 Host PC 102 Image forming device 201 CPU 235 Monitor 702 CPU 720 UI

Claims

1. An image processing device that performs image processing for printing a printed matter in which additional information is embedded, a setting means for setting a halftone pattern to be used in halftone processing executed on an image in which an encoded pattern is synthesized so as to be recognizable by a user from among a plurality of halftone patterns; a determining means for determining whether the coding pattern can be uniformly expressed after the halftone process is performed using the halftone pattern set by the setting means; and a change means for, when the determination means determines that the coding pattern cannot be uniformly expressed, changing the halftone pattern used in the halftone processing to another halftone pattern that can uniformly express the coding pattern.

2. The image processing device described in Claim 1, characterized in that the modification means changes the halftone pattern used in the halftone processing to another halftone pattern with the highest number of lines among multiple halftone patterns that can uniformly express the encoding pattern in the image synthesized with the encoding pattern.

3. A display means; 2. The image processing device according to claim 1, further comprising a display control means for displaying on said display means a selection screen for allowing a user to select a halftone pattern to be used in said halftone processing from a plurality of halftone patterns that can uniformly express said encoding pattern.

4. a priority order is set in advance for each of the plurality of halftone patterns; 2. The image processing device according to claim 1, wherein, when there are a plurality of halftone patterns that can uniformly express the encoding pattern, the change means changes the halftone pattern used in the halftone processing to another halftone pattern that has the highest priority among the plurality of halftone patterns that can uniformly express the encoding pattern.

5. 2. The image processing apparatus according to claim 1, wherein the other halftone pattern is a halftone pattern in which a screen angle of the image combined with the coding pattern does not match an angle of the coding pattern.

6. 2. The image processing apparatus according to claim 1, further comprising a printing means for printing a printed matter on which the coded pattern subjected to another halftone process using the other halftone pattern changed by the changing means is combined.

7. 2. The image processing apparatus according to claim 1, wherein the image processing apparatus is an information processing apparatus that generates PDL data for causing a printing apparatus to print a printed matter on which the coded pattern has been combined.

8. A control method for an image processing device, comprising: a setting step of setting a halftone pattern from among a plurality of halftone patterns to be used in halftone processing executed on an image in which the coded pattern is synthesized in a manner recognizable by a user; a determination step of determining whether the coding pattern can be uniformly expressed after the halftone process is performed using the halftone pattern set in the setting step; and a change step of changing the halftone pattern used in the halftone processing to another halftone pattern that can uniformly express the coding pattern if it is determined in the determination step that the coding pattern cannot be uniformly expressed.

9. A program for causing a computer to execute a control method for an image processing device, The control method for the image processing device includes: a setting step of setting a halftone pattern from among a plurality of halftone patterns to be used in halftone processing executed on an image in which the coded pattern is synthesized in a manner recognizable by a user; a determination step of determining whether the coding pattern can be uniformly expressed after the halftone process is performed using the halftone pattern set in the setting step; and a change step of changing the halftone pattern used in the halftone processing to another halftone pattern that can uniformly express the coding pattern if it is determined in the judgment step that the coding pattern cannot be uniformly expressed.

10. The program described in Claim 9, characterized in that in the modification process, the halftone pattern used in the halftone processing is modified to another halftone pattern with the highest number of lines among multiple halftone patterns that can uniformly express the encoding pattern in the image synthesized with the encoding pattern.

11. The program described in Claim 9, characterized in that the control method of the image processing device further includes a display control step of displaying on a display means a selection screen that allows a user to select a halftone pattern to be used in the halftone processing from a plurality of halftone patterns that can uniformly express the encoding pattern.

12. A priority order is preset for each of the plurality of halftone patterns, The program according to claim 9, characterized in that, when there are multiple halftone patterns that can uniformly express the encoding pattern, in the change process, the halftone pattern used in the halftone processing is changed to another halftone pattern that has the highest priority among the multiple halftone patterns that can uniformly express the encoding pattern.

13. The program described in Claim 9, characterized in that the other halftone pattern is a halftone pattern in which the screen angle of the image into which the encoding pattern is synthesized does not match the angle of the encoding pattern.

14. The control method for the image processing device comprises:

10. The program according to claim 9, further comprising a printing step of printing a printed matter on which the coding pattern subjected to another halftone process is synthesized using the other halftone pattern changed in the change step.

15. The program described in Claim 9, characterized in that the image processing device is an information processing device that generates PDL data for printing a printed material into which the encoding pattern has been synthesized on a printing device.

Images