JP2009194538A - Apparatus, method, program and storage medium for processing two-dimensional code - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To print a two-dimensional code in the number of pixels in accordance with the performance of a printing means in printing the two-dimensional code including each component formed of a plurality of elements with a printing means. <P>SOLUTION: The number of pixels of each element suitable for the printing of the two-dimensional code is compared with the number of pixels of each element of the two-dimensional code as a printing object. When matching cannot be attained, a changing means is provided which can change the number of pixels of each element of the two-dimensional code as the printing object before the printing means prints the two-dimensional code as the printing object. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that superimposes additional information on an image and outputs the image, and an image processing method. In particular, when the image forming apparatus that generates the additional information and the image forming apparatus that prints the additional information on the image are different, regardless of the difference in the characteristics of the image forming apparatus that generates the additional information and the image forming apparatus that prints, The present invention relates to an image forming apparatus having means for printing additional information in a desired state.

  Image forming apparatuses such as printers and copiers have become more sophisticated due to improved performance, making it possible to perform various image processing on originals. Specifically, there has been a request such as a copy prohibition setting for a document, a user restriction function for copying, or a serial number of a device printed for document tracking is embedded in an image.

  Therefore, in recent years, when an image is printed on recording paper, the information described above is generated as a dot pattern, and is printed on a document by superimposing it on the image (hereinafter, using the dot pattern). Information to be superimposed on the image is referred to as additional information). As a result, when the image printed with the additional information superimposed is copied by the image forming apparatus or scanned by the image reading apparatus, the image forming apparatus and the image reading apparatus read the dot pattern to stop the copying or scanning process or the user. Authenticate.

  FIG. 9 is a block diagram illustrating an example of a method for embedding additional information in an image. In FIG. 9, an image to be printed is stored in the image memory 901. The image data stored in the image memory 901 is stored in various states such as RGB, CMYK, YUV, and K.

  The image data output from the image memory 901 is input to the color conversion unit 902 and converted into four components of C (cyan), M (magenta), Y (yellow), and E (black).

  In addition, various correction processing units 903 perform correction processing on each component of CMYK. Next, the pseudo gradation processing unit 904 performs pseudo gradation processing using a method such as a systematic dither method or an error diffusion method.

  By superimposing (adding) the additional information generated by the additional information generation unit 905 on the Y component to the image data subjected to the above processing, and inputting the respective components to the printer engine 906, the image information Print an image with information other than.

  Hereinafter, an example of a method for embedding additional information in a dot pattern will be described with reference to FIGS. 10, 11, and 14.

  In FIG. 10, reference numeral 1001 denotes a part of a region where a dot pattern is formed, and black dots shown in FIG. 10 indicate reference points for embedding additional information in the dot pattern. The reference points are arranged in the printable area on the document at intervals of N pixels in the main scanning and sub-scanning directions. The additional information is embedded in the image using the positional relationship between the reference point shown in FIG. 10 and the dots actually printed near the reference point. FIG. 10 illustrates an example in which values are embedded according to the positional relationship between 16 reference points surrounded by a dotted line 1003 and each dot pattern printed near the reference point.

  FIG. 11 is an enlarged view of the vicinity of each of the reference points shown in FIG. 10, and each square shown in the figure represents a pixel that performs printing. FIG. 11 is composed of a total of 25 pixels, 5 pixels in the main scanning direction and 5 pixels in the sub-scanning direction. A pixel indicated by 1101 in the figure (represented by e in the figure) represents a reference point in FIG. 10, and FIG. 11 shows the ± 2 pixels in the main scanning direction and ± 2 pixels in the sub-scanning direction centering on the reference point. Represents an area.

  In FIG. 11, the dot pattern can be embedded with the values shown in FIG. 14 depending on which position of the pixel a, b, c, d, f, g, h, i is printed. It becomes.

  For example, when a dot pattern is printed at the position a (the position of −2 pixels in the sub-scanning direction and −2 pixels in the main scanning direction with respect to the reference point), the dot pattern represents a value of 0. Similarly, when a dot pattern is printed at the position b (the position of -2 pixels in the sub-scanning direction with respect to the reference point), a value of 1 is represented. Hereinafter, when a dot pattern is printed at each of the positions c, d, f, g, and h, values of 2, 3, 4, 5, and 6 are represented, and the position of i (the sub-scanning direction with respect to the reference point). When the dot pattern is printed at 2 pixels and 2 pixels in the main scanning direction), a value of 7 is represented.

  As described above, one dot pattern can represent a value of 0 to 7 depending on the reference point and the position where the dot pattern is printed, thereby embedding 3-bit information. When the dot pattern is printed on the reference point (position e in FIG. 11), this indicates that the dot pattern has no information.

  In 1003 of FIG. 10, the dot pattern described in FIG. 11 is composed of 16 pieces. Therefore, 16 dots surrounded by a dotted line 1003 in FIG. 10 can embed information of a maximum of 48 bits (3 bits × 16 pieces).

  However, if information is embedded in all the dots included in 1003 and dots are printed at positions different from the reference position, complicated processing is required to extract the reference position from the printed dot positions. Therefore, in this description, 8 dots that are not adjacent to each other in 1003 (indicated by 1002 in FIG. 10) are printed with dots at the reference position (denoted by e in FIG. 11) without embedding information. To do. Then, information is embedded in 8 dots other than 1002 and other than 1002 by the method shown in FIG. 11 to print the dots. As a result, 24-bit (3 bits × 8) additional information is embedded in the area 1003.

  Additional information by the dot pattern indicated by 1003 in FIG. 10 is repeatedly formed a plurality of times in the main scanning direction and the sub-scanning direction. Thus, for example, even if the dot pattern overlaps with the image of the document and the dot pattern cannot be read when the image is scanned, the added information is read by reading the dot pattern having the same information in other parts of the document. Can be acquired.

  Further, in FIG. 11, the dot pattern printing position is described as a position two pixels away from the reference point. However, in the method described above, additional information can be embedded in the dot pattern even at a distance other than two pixels.

  However, it is desirable to print at a distance of 2 pixels or more so that the embedded information can be acquired even if the dot pattern printing position is shifted by about 1 pixel due to factors such as the system of the image forming apparatus. It is. In general, dots are printed at a distance of about 2 to 4 pixels from the reference point in the main scanning direction and the sub-scanning direction, respectively.

  In the above description, the dot size printed as the dot pattern is described as one pixel. However, in order to detect the dot pattern by the image reading apparatus, a dot having a certain number of pixels is required. Therefore, in general, the size of the dot pattern is expressed by about 4 to 9 pixels (2 pixels × 2 pixels to 3 pixels × 3 pixels).

  FIG. 12 shows a flowchart for extracting the additional information embedded in the image as a dot pattern from the image on which the additional information is superimposed.

  In order to extract additional information from an image on which additional information is superimposed, first, an image having a size greater than or equal to a predetermined size (the size of a dot in which additional information is embedded) is deleted to delete a dot embedded with additional information. Extraction is performed (1201). Thereby, the dots for information addition and reference point detection shown in FIG. 10 are extracted.

  However, in the processing of step 1201, image data having the same size as the dot in which the additional information is embedded remains, or the dot embedded with the additional information having a size larger than a predetermined value because it overlaps with the image data may be deleted. is there.

  Here, the dots extracted in step 1201 are formed in a certain size such as 2 pixels in the main scanning direction × 2 pixels in the sub scanning direction, or 3 pixels in the main scanning direction × 3 pixels in the sub scanning direction. Therefore, in the following description in FIG. 12, when the distance between dots (the number of pixels) is described, it represents the distance (number of pixels) from a predetermined position of one dot to a predetermined position of the other dot. Here, the predetermined position of the dot is, for example, an intersection of a line segment that bisects the maximum width of the dot in the main scanning direction and a line segment that bisects the maximum width in the sub-scanning direction (hereinafter, this position is referred to as a dot It can be considered as “center”.

  Next, for each dot pattern after the processing in step 1201, the distance (number of pixels) in the main scanning direction and the distance (number of pixels) in the sub-scanning direction to the closest dot are measured. For all dot patterns.

  FIG. 13 shows an example of a histogram of distances in the main scanning direction and the sub-scanning direction with the closest dot created in step 1202.

  In FIG. 13, the horizontal direction represents the distance (number of pixels) in the main scanning direction or sub-scanning direction from the target dot to the closest dot, and the vertical direction represents the number of corresponding dots.

  In FIG. 13, n is the number of pixels in the main search direction or sub-scanning direction moved from the reference point in order to embed information in each dot, and N is the distance (number of pixels) between the reference points.

  Hereinafter, the reason why the histogram as shown in FIG. 13 is constructed will be described with reference to FIG.

  In FIG. 11, for example, when the position of the target dot is a (−2 pixels in the main scanning direction and −2 pixels in the sub-scanning direction with respect to the reference point), the dot closest to the target dot is main scanned with respect to the target dot. A reference point dot on the left side in the direction or a reference point dot on the upper side in the sub-scanning direction.

  At this time, for example, if the closest dot is a reference point dot located on the left side in the main scanning direction, the distance between the target dot and the reference point dot located on the left side in the main scanning direction is N-2 pixels (N is a reference point). The number of pixels between points) is 2 pixels in the sub-scanning direction.

  If the closest dot is a reference point dot located on the upper side in the sub-scanning direction, the distance between the target dot and the reference point dot located on the upper side in the sub-scanning direction is 2 pixels in the main scanning direction and N-2 in the sub-scanning direction. This is a pixel (N is the number of pixels between reference points).

  Next, when the position of the target dot is b (-2 pixels in the sub-scanning direction with respect to the reference point), the dot closest to the target dot is the reference point dot located on the upper side in the sub-scanning direction with respect to the target dot. is there. At this time, the distance between the target dot and the reference point dot located on the upper side in the sub-scanning direction is 0 pixel in the main scanning direction and N-2 pixels in the sub-scanning direction.

  When the position of the target dot is c (2 pixels in the main scanning direction and -2 pixels in the sub scanning direction with respect to the reference point), the dot closest to the target dot is on the right side of the main scanning direction with respect to the target dot. It is a reference point dot that is located or a reference point dot that is located on the upper side in the sub-scanning direction. At this time, for example, if the closest dot is a reference point dot located on the right side in the main scanning direction, the distance between the target dot and the reference point dot located on the left side in the main scanning direction is N-2 pixels in the main scanning direction, and the sub scanning direction. 2 pixels. If the closest dot is a reference point dot located on the upper side in the sub-scanning direction, the distance between the target dot and the reference point dot located on the upper side in the sub-scanning direction is 2 pixels in the main scanning direction and N-2 in the sub-scanning direction. This is a pixel (N is the number of pixels between reference points).

  Similarly, when the position of the target dot is d, f, g, h, i, the distance from the nearest dot is 0 pixel, 2 pixel, or N-2 pixel in both the main scanning direction and the sub-scanning direction. Thereby, a histogram as shown in FIG. 13 is obtained. In the case of FIG. 11, n = 2 in FIG. Thus, a histogram is created by performing the processing of step 1202, and the distance N between the reference points and the number n of pixels moved from the reference point to embed information are obtained from the histogram value (1204).

  If the number N of pixels between the reference points and the number n of pixels moved from the reference points for embedding information are known in advance, steps 1202 and 1203 need not be performed.

  Next, the distance (number of pixels) between the target dot and a dot at a position that is an even multiple (2, 4, 6, 8,...) Of the reference conversion distance N acquired in step 1203 is obtained. A histogram is generated (1204).

  When the target dot is a dot in which information is embedded, the dots at the positions of 2N, 4N, 6N, and 8N pixels are also dots in which information is embedded. Therefore, the distance in the main scanning direction and the sub scanning direction is 0 pixel, n pixel, 2n pixel, 2N-2n pixel, 2N-n pixel, 2N pixel, 2N + n pixel, 2N + 2n pixel, 4N-2n pixel, 4N-n pixel,. A plurality of histograms are generated in the vicinity of the N pixel interval between the n pixels. This makes it possible to detect dots in which information is embedded.

  Further, since the additional information by the dot pattern is repeatedly formed in the main scanning direction and the sub-scanning direction, dots in which the same information is embedded are generated at a predetermined interval. As a result, when the distance between the dots is measured between the dots embedded with the same information, the histogram of the distance in the main scanning direction and the sub-scanning direction appears only in the portions of 0, 2N, 4N, 6N, and 8N.

  For example, in the case of FIG. 10, since one additional information is embedded with 4 dots in the main scanning direction and 4 dots in the sub-scanning direction, the distance between the dots in the main scanning direction and the 4 sub-scanning direction dots is measured. The number of pixels is always 4N. As a result, the number of dots in the main scanning direction and the number of dots in the sub-scanning direction that constitute one additional information can be detected (1205).

  On the other hand, when the target dot is printed at the reference point as indicated by 1002 in FIG. 10, the dots at the positions of 2N, 4N, 6N, and 8N pixels are also printed at the reference point.

  For this reason, the histogram of the distance in the main scanning direction and the sub-scanning direction always appears only in the portions of 0, 2N, 4N, 6N, and 8N. As a result, a dot printed at the reference point (information is not embedded) is detected (1206).

  If the dot in which information is embedded and the dot printed on the reference point are found in steps 1205 and 1206, the embedded information is detected from the positional relationship between the dot in which information is embedded and the reference point (1207).

  Then, the information embedded in all the dots constituting the additional information is detected and the additional information is extracted (1208).

  In the copying operation, when the dot pattern image described in FIGS. 10 to 11 is superimposed and printed, the dot pattern image of the additional information is formed after the image is scanned by the image reading device. After generation, it is superimposed on the image and printed. In addition, when a dot pattern image is superimposed and printed on an image formed by a computer or the like, after obtaining image data and additional information from the computer, a dot pattern image is created from the additional information as shown in FIG. Then, it is superimposed on the image and printed. In these operations, image acquisition, dot pattern image generation from additional information, image and dot pattern image superposition and printing are performed as a series of operations.

  Here, consider an operation in the case where a scanned image or an image transferred to an image forming apparatus is temporarily stored in a storage device, and then printing is performed by designating an image in the storage device. At this time, the scanned or transferred image is stored in the storage device, and the dot pattern image of the additional information is formed and stored in the storage device in the same manner as the image. At the time of printing, the designated image and the dot pattern image corresponding to the image are acquired from the storage device and superimposed to perform printing.

  The reason why the additional information dot pattern image is generated before printing is that it takes time to generate the dot pattern image in which the additional information is embedded, which is unnecessary time for printing. This is a process for avoiding this.

  At this time, the formed dot pattern image is generated by controlling the dot density and the number of pixels (size) on the assumption that printing is performed in the state of the image forming apparatus when the dot pattern image is generated. However, it is conceivable that when the printing is performed, the dot density is printed lightly due to the change of the image forming apparatus with time or the surrounding environment, and the recognition rate of the embedded information is lowered. On the other hand, it is conceivable that the dot density becomes high and the image quality deteriorates due to the dots appearing more than necessary on the document.

  In order to solve the above problem, in Reference 1, calibration data, which is a printing characteristic of an image forming apparatus, is acquired when printing, and the density at which a dot pattern image is actually printed is obtained from the acquired calibration data. calculate.

A method has been proposed in which printing is performed after adjusting the density value to be higher when the dot pattern is output more thinly than when the dot pattern image is formed.
JP 2006-215745 A

  However, in the above conventional example, since the density of the dot pattern is corrected by referring only to the calibration data at the time of printing, the image forming apparatus that generates the dot pattern image of the additional information is the same as the image forming apparatus that performs printing. It is assumed that it is a device. Therefore, for example, after generating a dot pattern image of an image and additional information, when the image and the dot pattern image of additional information are transferred to another image forming apparatus and printed by the destination image forming apparatus, the density is determined by calibration data. Could not be corrected.

  In addition, if the image forming apparatus that generates the dot pattern image of the additional information and the image forming apparatus that performs printing have different performance and specifications such as the number of gradations and the number of gradations, dots can be printed at the desired density and size. There wasn't.

  Furthermore, when the dot pattern image is generated with multi-value data, there is a problem that the capacity of the dot pattern image increases.

  In order to solve the above problems, the apparatus according to claim 1 of the present application has the following means.

First acquisition means for acquiring the number of pixels of each element constituting the two-dimensional code to be printed;
Second acquisition means for acquiring the number of pixels of each element of the two-dimensional code when the printing means prints the two-dimensional code on a sheet;
If the number of pixels of each element acquired by the first acquisition unit and the number of pixels of each element acquired by the second acquisition unit do not match, the two-dimensional code to be printed is set as the printing unit. Changing means for changing the number of pixels of each element of the two-dimensional code to be printed before printing.

  According to the present invention, when the device that generates the additional data is different from the device that performs printing by superimposing the image and the additional data, the additional data depends on the setting value of the device that generates the additional data and the setting value of the device that performs the printing. Is corrected.

  As a result, it is possible to superimpose additional data on an image without being affected by differences in setting values and / or product specifications between apparatuses.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a block diagram showing the configuration of the embodiment according to the present invention.
In FIG. 2, a local area network (LAN) 201 connects a computer 202 (to be described later) and a multifunction printer (hereinafter referred to as MFP) 203 as an image forming apparatus. A computer 202 generates and edits image data and additional information to be superimposed on the image data by a user. The computer 202 is connected to the LAN 201, and the generated image data and additional information are sent to the MFP 203 via the LAN 201.

  Reference numeral 203 denotes an MFP connected to the LAN 201, which acquires image data and additional information sent via the LAN 201. Further, a dot pattern image in which the additional information as shown in FIG. 10 is embedded is generated from the acquired additional information, and is printed by being superimposed on the image data at the time of printing.

  In FIG. 2, the computer 202 and the MFP 203 connected to the LAN 201 are described as one for simplification, but a plurality of computers and MFPs are connected to the normal LAN 201. The computer 202 selects a desired MFP from a plurality of MFPs connected to the LAN 201 and outputs image data and additional information. The selected MFP acquires the sent image data and additional information, generates a dot pattern image from the additional information, and superimposes it on the image data for printing.

FIG. 3 is a block diagram showing the internal structure of the computer 202.
In FIG. 3, reference numeral 301 denotes a central processing unit (CPU) that controls the entire computer 202. A ROM 302 stores various control programs processed by the CPU 301. Reference numeral 303 denotes a RAM which loads and stores application programs and the like stored in an external storage device 306 to be described later. The CPU 301 executes processing by a program loaded on the RAM 303. The RAM 303 provides a work area when the CPU 301 executes various controls.

  Reference numeral 304 denotes a display that performs various displays under the control of the CPU 301. Reference numeral 305 denotes an input unit that performs necessary input using a keyboard, a pointing device, or the like. Reference numeral 306 denotes an external storage device that stores various application programs. A network interface 307 performs data communication with other devices connected to the network.

  2 is connected to the network interface 307, and the computer 202 is connected to the LAN 201 via the network interface 307.

  The CPU 201, ROM 202, RAM 203, display 204, input / output device 205, external storage device 206, and network interface 207 are each connected by an internal bus 208 of the computer.

  When additional information is superimposed on image data generated by the computer 202 and printed, the computer 202 outputs the image data and additional information to a predetermined printer.

  FIG. 6 shows an example of a setting screen for outputting image data to the printer in the computer 202. In FIG. 6, reference numeral 601 denotes an area for selecting a printer to output image data. The computer 202 outputs image data and additional information to the printer displayed in this area. In the printer selection area, a plurality of printers connected to the network can be displayed and selected.

  Reference numeral 602 denotes a part for displaying information related to the printer selected in 601. In this embodiment, the printer status, printer model name, installation location, and the like can be displayed. Reference numeral 603 denotes an area for setting the print range of the image data. In this embodiment, the image data can be selected from “print all image data”, “print only one designated page”, and “print by designating the page to be printed”. I can do it.

  Reference numeral 604 denotes a button for shifting to a screen for performing detailed settings for the print operation, and settings such as the size of the document to be printed, the vertical and horizontal directions, and the scaling ratio can be made. The additional information to be superimposed on the image data can also be set by pressing this button and shifting to the setting screen.

  Reference numeral 605 denotes a check box for superimposing additional information on image data. When this check box is checked, the computer 202 outputs image data and additional information to be superimposed on the image data. If the check box 605 is not checked, only the image data is output and no additional information is superimposed.

  Reference numeral 606 denotes a check box for printing a color image in black and white. When this check box is checked, image data is converted into black and white in the computer. Reference numeral 607 denotes an area for designating the number of image data to be printed. The image data is printed the number of times designated by one printing operation.

  Reference numeral 608 denotes a print button. When this button is pressed, the processing of the contents set in 603 to 607 is performed on the image data, and the image data and additional information are output to the printer selected in 601. Reference numeral 609 denotes a cancel button. When this button is pressed, the contents set on the setting screen of FIG. 6 are canceled.

FIG. 4 is a block diagram showing the internal structure of the MFP 203.
Reference numeral 401 in the figure denotes an operation panel unit in which dials and switches operated by the user are arranged. Settings for operation instructions such as copying and fax transmission, enlargement / reduction ratio, and input of a telephone number of a transmission destination are set on this operation panel unit. To do.

  A reader (reading unit) 402 photoelectrically scans a document to form an image signal. An original is placed on the original platen of the reader, and photoelectric elements such as CCDs arranged in a line in the main scanning direction are moved in the direction perpendicular to the element arrangement direction (sub-scanning direction) to read the original to generate electrical image data. . The image data read by the reader is stored in the buffer memory via the reader control unit.

  Reference numeral 403 denotes a printer that forms image data read by the reader or image data sent via the LAN 201 on a recording sheet. An electrophotographic printer is connected to the MFP of this embodiment. The image data is output to the printer by sending the image data stored in the buffer memory to the printer via the printer control unit.

  The internal block of the printer 403 has the same configuration as that shown in FIG. Therefore, when the MFP 203 performs printing by superimposing the image data and the dot pattern image, the dot pattern image in which the image data and the additional information are embedded is stored in the buffer memory. Then, by sending the dot pattern image together with the image data to the printer 403, the image data on which the dot pattern image is superimposed is printed.

  Reference numeral 404 denotes image data read by the reader 402, image data sent via the LAN 201, additional information, dot pattern images and setting values (dot types and dot shapes to be described later) representing information related to the dot pattern images. A storage device for storing. The storage device 404 is composed of a nonvolatile memory such as a hard disk. When image data and a dot pattern image are stored in the storage device, or when image data and a dot pattern image stored in the storage device are read, storage and reading are performed via a buffer memory described later.

  Reference numeral 405 denotes an operation panel control unit that controls the operation panel unit 401. The operation panel control unit 405 analyzes an instruction from the user input through the operation panel and sends the instruction content to a microprocessor unit described later.

  A reader control unit 406 controls the reader 402. The reader 402 is driven by an instruction from the microprocessor unit to read a document on the document table and store the read image data in a buffer memory.

  A printer control unit 407 controls the printer 403. The printer control unit 407 acquires image data and a dot pattern image from the buffer memory according to an instruction from the microprocessor unit, and outputs the image data and the dot pattern image to the printer 403. Further, by driving the printer 403 in accordance with the output of the image data, the image is printed on the recording paper and output.

  A storage device control unit 408 controls the storage device 404 and stores data from the buffer memory to the storage device 404 and outputs data from the storage device 404 to the buffer memory according to instructions from the microprocessor unit.

  Reference numeral 409 denotes a microprocessor unit that controls the overall operation of the MFP 203. By instructing each block, the MFP 203 performs various operations such as scanning, printing, and fax reception / transmission. The microprocessor unit 409 includes a ROM for storing a program for operating the MFP and a RAM for temporarily storing data necessary for control.

  The ROM in the microprocessor unit 409 stores a set value list for determining a dot shape (number of pixels) when generating a dot pattern image from additional information. When generating the dot pattern image from the additional information, the microprocessor unit determines the dot shape (number of pixels) by referring to the setting value list stored in the ROM, and sets the dot according to the specified shape (number of pixels). Forming a dot pattern image.

  Further, when image data, a dot pattern image, and a setting value representing the shape of a dot included in the dot pattern image are transferred from another MFP via the LAN 201, the microprocessor unit 409 performs the following operation. That is, referring to the set value sent and the set value list stored in the ROM, the dot shape (number of pixels) included in the dot pattern image is changed to generate a new dot pattern image.

  Reference numeral 410 denotes a buffer memory. When an operation such as reading a document from the reader 402, reading image data from the storage device 404, or acquiring image data and additional information via the LAN 201 is performed, each image data is once stored in the buffer memory. 410 is stored.

  When performing operations such as printing image data from the printer 403, storing image data in the storage device 404, or outputting image data via the LAN 201, each image data is output from the buffer memory 410.

  An encoding / decoding processing unit 411 encodes (compresses) the image data stored in the buffer memory 410 when necessary, or decodes (decompresses) the compressed image data. Do.

  Reference numeral 412 denotes an image processing unit, which performs image processing and processing for improving image quality instructed by the user through the operation panel 401.

  Reference numeral 413 denotes an internal bus that connects the blocks, and image data is transferred and commands and setting values for operating the blocks are transmitted and received via the internal bus 414.

  Reference numeral 414 denotes a network control unit, and the internal bus 413 is connected to the external LAN 201 via the network control unit. The network control unit 414 performs protocol conversion between the external LAN 201 and the internal bus 413. As a result, image data input via the external LAN can be stored in the buffer memory 410, printed from the printer 403, and stored in the storage device 404 in the same manner as image data read from the reader 402.

  The dot pattern image generated in the present embodiment is generated as a binary image in order to reduce the data amount.

  FIG. 5 is a flowchart illustrating an operation in which the MFP 203 forms a dot pattern image when image data and additional information are acquired from the LAN 201.

  In FIG. 5, first, the MFP 203 acquires image data and additional information output from the computer via the LAN 201 (501). The acquired image data is temporarily stored in the buffer memory 410 and then stored in the storage device 404 via the storage device operation unit 408. The additional information is also stored in the storage device 404 (502).

  When image data and additional information are stored in the storage device 404, the MFP 203 selects a dot type for embedding the additional information (503). This is because when the additional information is superimposed on the image by the dot pattern image, the size of the dots printed on the recording paper is not changed depending on the image forming apparatus due to a difference in each image forming apparatus such as printer engine performance and calibration. It is the structure for making.

  Accordingly, an object is to make the dots of the dot pattern image printed on the recording paper substantially the same size by selecting the same kind of dot type in any image forming apparatus.

Hereinafter, the utility of selecting the dot type will be described with a specific example.
FIG. 15 is an example of a set value list representing the correlation between the dot type and the number of dots forming a dot pattern image in which additional information is embedded when each dot type is selected, and the dot shape. In FIG. 15, four types of dot shapes (number of pixels) can be selected as the dot type. When dot types 1 to 4 are selected, the dot shape (number of pixels) is 5 to 8 pixels respectively. A pattern image is formed.

  Here, a plurality of dot types, that is, a dot pattern (number of pixels) for forming a dot pattern image, is prepared so that a user or an administrator of the MFP can select the dot shape (number of pixels). It is to do.

  FIG. 16 is an example of a set value list for an image forming apparatus in which an image printed on a recording sheet becomes large due to individual differences such as printer engine performance and calibration. In FIG. 16, when dot types 1 to 4 are selected, a dot pattern image is formed with a dot shape (number of pixels) of 4 to 7 pixels, respectively. Therefore, in the image forming apparatus in which the image printed on the recording paper becomes large due to individual differences, correction is made so that the size of each dot is smaller than when the dot pattern image is formed using the set value list of FIG. Is done.

  FIG. 17 is an example of a set value list for an image forming apparatus in which an image printed on a recording sheet becomes small due to individual differences such as printer engine performance and calibration. In FIG. 17, when dot types 1 to 4 are selected, a dot pattern image is formed with dot shapes (number of pixels) of 6 to 9 pixels, respectively. Therefore, in the image forming apparatus in which the image printed on the recording paper becomes small due to individual differences, correction is performed so that the size of each dot is larger than when the dot pattern image is formed using the setting value list of FIG. Is done.

  As described above, the dots of the dot pattern image are printed on the recording paper to approximately the same size by correcting the individual differences between the image forming apparatuses using the set value list indicating the correlation between the dot type and the number of dot pixels. can do.

  In this embodiment, it is assumed that the set value list is stored in a ROM in the microprocessor 409. Further, the set value list is not fixed, and when the characteristics of the image forming apparatus change, the value of the number of dot pixels for each dot type can be changed.

  As described above, the dot type for forming the dot pattern image is selected (503), and the dot shape (number of pixels) corresponding to the dot type selected in step 503 is selected with reference to the setting list (504). .

  Thereafter, using the dot shape (number of pixels) selected in step 504, a dot pattern image in which additional information is embedded is generated by the method described in FIGS. 10, 11, and 14 (505), and the generated dot pattern image is generated. Is stored in the recording device 404 (506). Further, the dot type selected in step 503 and the shape (number of pixels) of the dot selected in step 504 are stored in the recording device 404 (507).

  Since the dot pattern image in which the additional information is embedded can be generated by the above operation, the additional information is deleted from the recording device 404 (508), and the operation of forming the dot pattern image is ended.

Note that the image data, dot pattern image, selected dot type, and dot shape (number of pixels) information stored in the storage device 404 by the operation shown in FIG. Is done.
(Hereinafter, the selected dot type and dot shape are referred to as “setting values”)
FIG. 1 is a flowchart illustrating an operation in which the MFP 203 re-forms a dot pattern image when image data, a dot pattern image, and a setting value are sent from another image processing apparatus connected to the LAN 201.

  In FIG. 1, first, the MFP 203 acquires image data, a dot pattern image, and setting values from the image forming apparatus connected to the LAN 201 via the LAN 201 (101). The acquired image data is temporarily stored in the dot pattern image buffer memory 410 and then stored in the storage device 404 via the storage device operation unit 408. Similarly, the set value is also stored in the storage device 404 (102).

  When the image data dot pattern image and the setting value are stored in the storage device 404, the MFP 203 performs processing for converting the shape (number of pixels) of the dots forming the dot pattern image into the shape (number of pixels) printed by the MFP 203. This refers to whether or not the relationship between the dot type and the dot shape of the setting value stored in the storage device 404 is the same as the content of the setting value list held by the MFP 203. This is because it is necessary to correct the contents of the list.

  Therefore, the set value stored in the recording device 404 is referred to, and the dot type and the dot shape (number of pixels) forming the dot pattern image are acquired (103, an example of a first acquisition step). That is, the number of pixels of each element (each dot) constituting the two-dimensional code to be printed is acquired. Next, referring to the setting value list of the MFP 203, the dot shape (number of pixels) corresponding to the dot type acquired in step 103 is acquired (104, an example of a second acquisition step). That is, when the printing unit of the MFP 203 prints a two-dimensional code, information indicating how many pixels should be formed for each element is acquired by referring to the setting value list.

  Then, the dot shape (number of pixels) forming the dot pattern image acquired in step 103 is compared with the dot shape (number of pixels) in the MFP 203 acquired in step 104 (105).

  As a result of the comparison, if both are equal (match), the dot pattern image stored in the storage device 404 is in a state where it can be printed superimposed on the image data, so the processing ends.

  On the other hand, as a result of the comparison in step 105, if the dot shapes (number of pixels) of the two are different (do not match), the dot pattern image is changed to a shape that is superimposed on the image data. That is, the two-dimensional code to be printed is changed to a two-dimensional code suitable for printing on the printing unit. Specifically, the number of pixels of each element of the two-dimensional code is changed to the number of pixels acquired in 104. In other words, the dot shape (number of pixels) forming the dot pattern image is changed to the dot shape (number of pixels) of the MFP acquired in step 104 (106).

  The dot pattern image generated in step 106 (dot pattern image after the dot shape is changed to the MFP shape) is stored in the recording device 404 as a new dot pattern image (107). Thereafter, the dot shape of the setting value stored in the recording device 404 is changed to the dot shape of the MFP acquired in step 104 (108).

  With the above operation, even when the dot shape (number of pixels) of the dot pattern image sent from another image processing apparatus is different from the number of pixels to be superimposed at the time of printing, the number of pixels is corrected and superimposed with the image data. A dot pattern image for printing can be generated.

  An example of a method for changing the dot shape of the dot pattern image in step 106 in FIG. 1 is pixel value control using pattern matching. FIG. 18 shows an example of a circuit that changes the pixel value by the pattern matching.

  In FIG. 18, reference numeral 1801 denotes a pixel of interest (in FIG. 18, the i-th pixel in the main scanning direction and the j-th pixel in the sub-scanning direction) -2 pixels to 2 pixels in the main scanning direction and -2 pixels to 1 in the sub-scanning direction. This is a buffer that holds binary image data for 20 pixels existing in a pixel area.

  Of the image data held in the buffer, image data for 19 pixels excluding the target image is input to the data comparison unit 1802.

  Reference numeral 1802 denotes a pattern matching unit. When the 19 binary image data input from the buffer 1801 satisfy all the conditions set in 1802, 1 is output from the Result. When the binary image data does not satisfy the set condition, 0 is output from the Result.

  Reference numeral 1803 denotes a change value holding unit that holds a value in order to forcibly change the value of the pixel of interest when Result, which is the output of the pattern matching unit, is 1. When the target pixel when 1 is output from the Result is set to 0, 0 is set, and when 1 is set, 1 is set to 1803.

  Reference numeral 1804 denotes a selector which outputs the value of B from Y when the value input to SEL is 1, and outputs the value of A from Y when the value input to SEL is 1. The Result, which is the output of the pattern matching unit 1803, is input to the SEL input, and the value of the target pixel is input from the buffer 1801 to the A input. In addition, a value set in the change value holding unit 1803 is input to the B input.

  With the above configuration, the selector 1804 outputs the value set in the change value holding unit 1803 when the Result value is 1 (that is, when all the conditions for setting the binary image data value to 1802 are satisfied). On the other hand, when the Result value is 0 (that is, when there is image data that does not satisfy the condition set to 1802 in the binary image data), the value of the target pixel is output.

  FIG. 7 shows an example of processing for reducing the dot shape (reducing the number of pixels) using the pattern matching circuit shown in FIG. FIG. 7 illustrates a case where the dot shape of dot type 2 (dot pixel number 5) in FIG. 16 is changed to dot type 2 (dot pixel number 4) in FIG.

In FIG. 7, the following conditions are set in the pattern matching unit 1802.
D (i-2, j) = 1 Pixel value at the position of i-2, j = 1 (black)
D (i-1, j) = 1 Pixel value at the position of i-1, j = 1 (black)
D (i-2, j + 1) = 1 Pixel value at the position of i-2, j + 1 = 1 (black)
D (i-1, j + 1) = 1 Pixel value at the position of i-1, j + 1 = 1 (black)
Further, 0 (white) is set in the change value holding unit 1803.

  After the above setting, the dot image represented by 701 (dot of dot type 2 (dot pixel number 5 in FIG. 16)) is input to the pattern matching circuit. In 701, pixels indicated by diagonal lines are black (value is 1), and white pixels are pixels having a value of 0.

  In FIG. 7, when the pixel indicated by 702 in the dot image 701 becomes the position (i, j) of the target pixel in the buffer 1801, all the conditions described in the pattern matching unit 1802 are satisfied. Therefore, when the pixel 702 reaches the position (i, j) of the target pixel, the value 1 set in the change value holding unit 1803 is not output from the selector 1804 without outputting the value of the target pixel (1 in the case of 702). Is output.

  Further, when a pixel other than 702 becomes the position (i, j) of the target pixel in the buffer 1801, all the conditions described in the pattern matching unit 1802 are not satisfied. Therefore, the selector 1804 outputs the pixel value at the position (i, j) of the target pixel in the buffer 1801.

  With the above operation, as indicated by reference numeral 703, the pattern matching circuit outputs dots in which only the pixels 704 are changed to zero. Thereby, the dot shape of dot type 2 (dot pixel number 5) in FIG. 16 is changed to dot type 2 (dot pixel number 4) in FIG.

  FIG. 8 shows an example of processing for increasing the dot shape (increasing the number of pixels) using the pattern matching circuit shown in FIG. The process of reducing the number of pixels is described in another place. FIG. 8 illustrates a case where the dot shape of dot type 2 (dot pixel number 6) in FIG. 15 is changed to dot type 2 (dot pixel number 7) in FIG.

In FIG. 8, the following conditions are set in the pattern matching unit 1802.
D (i-1, j-2) = 1 Pixel value at the position of i-1, j-2 = 1 (black)
D (i, j-2) = 1 Pixel value at position i, j-2 = 1 (black)
D (i + 1, j-2) = 1 Pixel value at the position of i + 1, j-2 = 1 (black)
D (i-1, j-1) = 1 Pixel value at the position of i-1, j-1 = 1 (black)
D (i, j-1) = 1 Pixel value at the position of i, j-1 = 1 (black)
D (i + 1, j−1) = 1 Pixel value at the position of i + 1, j−1 = 1 (black)
Further, 1 (black) is set in the change value holding unit 1803.

  After the above setting, the dot image represented by 801 (dot of dot type 2 (dot pixel number 6 in FIG. 15)) is input to the pattern matching circuit.

  In FIG. 8, all the conditions described in the pattern matching unit 1802 are satisfied when the pixel indicated by 802 in the dot image 801 is the position (i, j) of the target pixel in the buffer 1801. Therefore, when the pixel 802 reaches the position (i, j) of the target pixel, the value 1 set in the change value holding unit 1803 without outputting the value of the target pixel (0 in the case of 802) from the selector 1804. Is output.

  Further, when a pixel other than 802 is the position (i, j) of the target pixel in the buffer 1801, all the conditions described in the pattern matching unit 1802 are not satisfied. Therefore, the selector 1804 outputs the pixel value at the position (i, j) of the target pixel in the buffer 1801.

  With the above operation, as indicated by reference numeral 803, only 804 pixels are changed to 1 from the pattern matching circuit. Thereby, the dot shape of dot type 2 (dot pixel number 6) in FIG. 15 is changed to dot type 2 (dot pixel number 7) in FIG.

  When the dot shape (number of pixels) forming the dot pattern image is changed by the method described in FIG. 1, FIG. 7 and FIG. 8, the center position of the dot before changing the dot shape is changed. The position of the center of the dot later changes. However, such dot shape change is performed for all dots included in the dot pattern image.

  Therefore, since the center positions of all the dots forming the dot pattern image change in the same manner, the distance between the center positions between the dots does not change. Therefore, even if the shape (number of pixels) of the dots forming the dot pattern image is changed, the additional information embedded in the image as the dot pattern is extracted from the image on which the additional information is superimposed by the method described in FIG. Is possible.

  In step 105 of FIG. 1, the dot shape (number of pixels) of the current dot pattern image stored in the storage device 404 is compared with the dot shape (number of pixels) designated by the MFP.

  Here, when both shapes (the number of pixels) are different, the number of pixels is changed in steps 106 to 108. This is performed in order to make the shape of the dot pattern printed on the recording paper the same size without depending on the image forming apparatus.

  However, in order to extract additional information embedded in an image as a dot pattern by the method described with reference to FIG. Therefore, if the dot shape (number of pixels) of the current dot pattern image stored in the storage device 404 in step 105 in FIG. 1 is greater than or equal to the dot shape (number of pixels) specified by the MFP, the number of pixels is changed. There is no need to do it.

  FIG. 19 is a flowchart showing an operation of re-forming a dot pattern image in consideration of the above contents. In FIG. 19, the dot shape (number of pixels) of the current dot pattern image is compared with the dot shape (number of pixels) designated by the MFP (1901). Only when the dot shape of the current dot pattern image is smaller than the dot shape (number of pixels) designated by the MFP, the number of pixels of the dot is changed.

Flow chart showing operation for re-forming dot pattern image Block diagram showing device configuration A block diagram showing an internal structure of the computer 202 Block diagram showing the internal structure of the MFP 203 A flowchart showing an operation in which the MFP 203 forms a dot pattern image. Example of setting screen for outputting image data to a printer An example of processing to reduce the dot shape An example of processing to increase the dot shape The block diagram which shows an example of the method of embedding additional information in an image Illustration of how to embed additional information in a dot pattern Illustration of how to embed additional information in a dot pattern Flow chart for extracting additional information Example of histogram of distance between dots in main scanning direction and sub-scanning direction Illustration of how to embed additional information in a dot pattern Example of setting value list Example of setting value list Example of setting value list An example of a circuit that changes the pixel value of a dot by pattern matching Flow chart showing operation for re-forming dot pattern image

Claims (9)

First acquisition means for acquiring the number of pixels of each element constituting the two-dimensional code to be printed;
Second acquisition means for acquiring the number of pixels of each element of the two-dimensional code when the printing means prints the two-dimensional code on a sheet;
If the number of pixels of each element acquired by the first acquisition unit and the number of pixels of each element acquired by the second acquisition unit do not match, the two-dimensional code to be printed is set as the printing unit. And changing means for changing the number of pixels of each element of the two-dimensional code to be printed before printing. Image acquisition means for acquiring images;
Generation means for generating additional data for adding information to the acquired image Storage means for storing the acquired image and additional data Addition means for generating an output image by adding the image and additional data stored in the storage means In the image forming apparatus having printing means for printing the added output image,
Setting value acquisition means for acquiring the setting value of the image forming apparatus;
Correction means for correcting the additional data;
The setting value of the image forming apparatus when the image is acquired by the image acquisition unit is acquired from the setting value acquisition unit, and the setting value is stored in the storage unit in association with the acquired image and the generated additional data.
When the image stored in the storage unit is printed by the printing unit, the setting value acquisition unit acquires the setting value of the image forming apparatus, and the setting value acquired from the setting value acquisition unit and the storage unit store the setting value. An image forming apparatus that corrects additional data by a correcting unit based on a stored set value, adds the corrected additional data to an image, and generates an image for output.   The image forming apparatus according to claim 2, wherein the additional data includes dots having a predetermined number of pixels.   The image forming apparatus according to claim 2, wherein the additional data is represented by a binary image.   The image forming apparatus according to claim 2, wherein the set value is the number of pixels constituting a dot.   The image forming apparatus according to claim 2, wherein the correcting unit increases or decreases the number of pixels constituting the dot. A first acquisition step of acquiring the number of pixels of each element constituting the two-dimensional code to be printed;
A second acquisition step of acquiring the number of pixels of each element of the two-dimensional code when the printing unit prints the two-dimensional code on the sheet;
If the number of pixels of each element acquired in the first acquisition step does not match the number of pixels of each element acquired in the second acquisition step, the two-dimensional code to be printed is printed as the printing unit. And a changing step of changing the number of pixels of each element of the two-dimensional code to be printed before printing on the apparatus.   A computer-readable program for causing a computer to execute the method for controlling an apparatus according to claim 7.   A computer-readable storage medium storing the program according to claim 8.

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