JP2018152721A - Image forming apparatus and background pattern area determination method and program using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus and the like which are created by an external device and can accept printing of image data in which a document image and a background pattern image are combined and can output a printed matter to which the background pattern image is added.SOLUTION: The image forming apparatus accepts printing of image data created in an external device and in which a document image 301 and a background pattern image 302 are combined and determines whether a specific image pattern composed of dot images exists for each predetermined area on the accepted image data to be printed. For a region which is determined to have a specific image pattern, a period of the specific image pattern is determined, and it is determined whether a first region in which the determined period is a first period and a second region in which the determined period is a second period exist, and when the first and second regions exist, those regions are determined to be background pattern image regions.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image forming apparatus such as an MFP (Multi Function Peripherals) which is a multi-function digital multi-function peripheral, a tint block area determination method, and a tint block area determination program.

  In recent years, as an application for a personal computer (hereinafter referred to as a PC), a tint block synthesis application capable of creating an image data with a tint block by synthesizing a document image and a tint block image has been provided.

  When the image forming apparatus such as an MFP accepts printing of image data with a background pattern synthesized by an external device such as a PC, there is a problem that the background pattern image intended by the user is not printed. The reason is as follows.

That is, in general, such a problem does not occur when a copy-forgery-inhibited pattern image is synthesized with an original image by the image forming apparatus. For example, when a copy-forgery-inhibited pattern image is synthesized by the image forming apparatus, for example, (a) a line width correction process is executed for “original image”.
(B) For the “background pattern image”, the processing step is passed without executing the line width correction process.
Thus, since the image forming apparatus can distinguish between “original image” and “background pattern image”, the original image and the background pattern image are combined after executing the respective processes ((a) and (b)). By printing, an output image intended by the user can be obtained.

  However, when the copy-forgery-inhibited pattern composition application is used on a PC and a composite image of “original image” and “background pattern image” is transmitted from the PC to the image forming apparatus, Therefore, the processing cannot be divided as in the above (a) and (b), and the processing is uniformly performed by an ASIC (application specific integrated circuit) for output image processing.

  At this time, if the density difference of the dot pattern in the background portion of the background pattern image generated by the background pattern synthesis application is greater than or equal to a certain level, the periphery of the dot is determined as an edge and recognized as a “line”. The dot pattern recognized as “line” is subjected to a line width correction process, and the dots are reduced by the thinning process and are not printed. That is, since the background portion is not printed, the latent image portion becomes obvious and the copy-forgery-inhibited pattern image can be identified. Further, when the dot pattern density is halftone, moire occurs in the background portion due to interference with the screen processing, the latent image portion becomes obvious, and the tint block image can be identified. For this reason, the copy-forgery-inhibited pattern image intended by the user cannot be printed.

  Patent Documents 1 to 4 propose techniques for separating a document image and a tint block image when printing is performed.

Japanese Patent Laying-Open No. 2015-135666 JP 2011-114736 A JP 2008-219418 A JP 2007-288592 A

  However, the techniques described in Patent Documents 1 to 4 have already added information for determining the tint block area to the print data. However, when the image data with a tint block to which such information is not added is transmitted from the PC to the image forming apparatus and printed, the tint block image intended by the user cannot be printed. The techniques described in Patent Documents 1 to 4 cannot provide a solution.

  The present invention has been made in view of such a technical background, and is prepared by an external device such as a PC, accepts printing of image data obtained by combining a document image and a copy-forgery-inhibited pattern image, and adds a copy-forgery-inhibited pattern image. Another object of the present invention is to provide an image forming apparatus capable of outputting a printed matter, a tint block area determination method and a tint block area determination program using the same apparatus.

The above problem is solved by the following means.
(1) An accepting unit that accepts printing of image data created by an external device and composed of a manuscript image and a tint block image, and a dot for each predetermined region with respect to image data to be printed accepted by the accepting unit. An image pattern determination unit that determines whether or not a specific image pattern composed of images exists, and a period of the specific image pattern for an area that is determined by the image pattern determination unit to have a specific image pattern Determining whether there is a first area in which the period of the specific image pattern determined by the period determining means is the first period and a second area having the second period A copy-forgery-inhibited pattern region determination unit that determines a region formed by the first and second regions as a copy-forgery-inhibited pattern image region when the first and second regions exist; An image forming apparatus comprising the.
(2) It further comprises density determination means for determining whether or not the density of the specific image pattern in the area where it is determined that the specific image pattern exists, and the copy-forgery-inhibited pattern area determination means uses the density determination means to determine the specific image. 2. The image forming apparatus according to item 1, wherein the pattern density is determined to be uniform and the areas having the same density are extracted, and whether the first and second areas are present in the extracted areas is determined. .
(3) The image forming apparatus further includes a constituent color determining unit that determines a constituent color of a specific image pattern in an area where it is determined that a specific image pattern exists, and the tint block region determining unit is configured to determine the specific color determined by the constituent color determining unit. 3. The image forming apparatus according to item 1 or 2, wherein regions having the same constituent colors of the image pattern are extracted, and whether or not the first and second regions are present in the extracted regions is determined.
(4) The image processing apparatus further includes area gradation determination means for determining the area gradation of the specific image pattern in the area determined to have the specific image pattern, and the tint block area determination means is determined by the area gradation determination means. 4. The method according to any one of the preceding items 1 to 3, wherein a region having the same area gradation of the specified image pattern is extracted, and whether or not the first and second regions are present in the extracted region is determined. Image forming apparatus.
(5) The image processing apparatus further includes an attribute determination unit that determines an attribute of the image data for each of the predetermined areas, and the attribute determination unit only applies to the area where the attribute of the image data is determined to be a character or a graphic. 5. The image forming apparatus according to any one of items 1 to 4, wherein the image pattern determination unit determines whether or not a specific image pattern exists.
(6) When it is determined that the first and second areas exist, the tint block area determination unit further determines whether or not the low frequency period is equal to or greater than a certain threshold value between the first period and the second period. The image forming apparatus according to any one of the preceding items 1 to 5, wherein when the low frequency period is determined to be equal to or greater than a certain threshold value, the first and second regions are determined to be the copy-forgery-inhibited pattern image region.
(7) When the copy-forgery-inhibited pattern area determination unit determines that the first and second areas exist, an area having a low period among the first and second areas is an area having a high period. And when it is determined that a region with a low cycle is surrounded by a region with a high cycle, the first and second regions are defined as regions of the tint block image. 7. The image forming apparatus according to any one of items 1 to 6 above.
(8) When the copy-forgery-inhibited pattern area determination unit determines that the first and second areas exist, an area having a high period among the first and second areas is a medium having a low period. And when it is determined that a region with a high cycle is surrounded by a region with a low cycle, the first and second regions are defined as regions of the tint block image. 7. The image forming apparatus according to any one of items 1 to 6 above.
(9) When it is determined by the tint block area determination means that the first and second areas exist, an image of an area having a low period among the first and second areas is set as a monochromatic solid pattern, and the period is Image data creation means for creating image data in which an image in an area with a high cycle is erased, and character recognition processing is performed on the image data created by the image data creation means to form characters in an area with a low cycle Character recognition means for determining whether or not a character is formed, and when the character recognition means determines that a character is formed in an area having a low cycle, the copy-forgery-inhibited pattern area determination means 9. The image forming apparatus according to any one of the preceding items 1 to 8, wherein the second area is determined to be a tint block image area.
(10) Image processing means for performing different image processing on the first and second areas determined by the copy-forgery-inhibited pattern area determination means as areas of the copy-forgery-inhibited pattern image and other areas, and the image processing means The image forming apparatus according to any one of the preceding items 1 to 9, further comprising: a printing unit that prints image data subjected to image processing.
(11) An accepting step for accepting printing of image data created by an external device and composed of a manuscript image and a tint block image, and a dot for each predetermined area for image data to be printed accepted by the accepting step. An image pattern determination step for determining whether or not a specific image pattern composed of images exists, and a period of a specific image pattern for an area determined to have a specific image pattern by the image pattern determination step Determining whether there is a first area in which the period of the specific image pattern determined in the period determining step is the first period, and a second area in which the second period is the second period When the first and second areas exist, the area constituted by the first and second areas is defined as the area of the tint block image. The image forming apparatus background pattern area determination method according to, characterized in that it includes a background pattern area determining step of constant, the.
(12) It further includes a density determination step for determining whether or not the density of the specific image pattern is uniform in an area where it is determined that a specific image pattern exists, and in the tint block area determination step, the specific image is determined by the density determination step. 12. The tint block region determination according to item 11 above, wherein a region in which the density of the pattern is determined to be uniform and the concentration is equal is extracted, and whether or not the first and second regions are present in the extracted region is determined. Method.
(13) A composition color determining step for determining a constituent color of a specific image pattern in an area where it is determined that a specific image pattern is present, and in the tint block area determining step, the specific color determined by the constituent color determining step 13. The tint block region determination method according to item 11 or 12, wherein regions having the same constituent colors of the image pattern are extracted, and whether or not the first and second regions are present in the extracted regions is determined.
(14) An area gradation determination step of determining an area gradation of a specific image pattern in an area determined to have a specific image pattern is further provided, and the ground pattern area determination step is determined by the area gradation determination step. 14. The method according to any one of the above items 11 to 13, wherein a region having the same area gradation of the specified image pattern is extracted, and whether or not the first and second regions are present in the extracted region is determined. Background pattern area determination method.
(15) The method further includes an attribute determination step for determining an attribute of the image data for each certain area, and the attribute determination step is performed only on the area where the attribute of the image data is determined to be a character or a graphic. 15. The tint block region determining method according to any one of the preceding items 11 to 14, wherein it is determined whether or not a specific image pattern exists in the image pattern determining step.
(16) In the copy-forgery-inhibited pattern area determination step, when it is determined that the first and second areas exist, it is further determined whether or not the low frequency period is equal to or greater than a certain threshold value among the first period and the second period. The tint block region determining method according to any one of the preceding items 11 to 15, wherein the first and second regions are determined to be the tint block image regions when it is determined that the low frequency period is equal to or greater than a certain threshold.
(17) In the copy-forgery-inhibited pattern area determination step, when it is determined that the first and second areas exist, an area having a low period among the first and second areas is an area having a high period. And when it is determined that a region with a low cycle is surrounded by a region with a high cycle, the first and second regions are defined as regions of the tint block image. 17. The tint block region determination method according to any one of the preceding items 11 to 16.
(18) In the copy-forgery-inhibited pattern area determination step, when it is determined that the first and second areas exist, an area having a high period among the first and second areas is a medium having a low period. And when it is determined that a region with a high cycle is surrounded by a region with a low cycle, the first and second regions are defined as regions of the tint block image. 17. The tint block region determination method according to any one of the preceding items 11 to 16.
(19) If it is determined in the tint block region determination step that the first and second regions exist, an image of a region having a low cycle among the first and second regions is set as a monochromatic solid pattern, and the cycle is An image data creation step for creating image data in which an image in a region with a high cycle is erased, and character recognition processing is performed on the image data created by the image data creation step to form a character in a region with a low cycle A character recognition step for determining whether or not a character is formed, and when the character recognition step determines that a character is formed in an area having a low cycle, 19. The tint block region determining method according to any one of the preceding items 11 to 18, wherein the second region is determined to be a tint block image region.
(20) An image processing step for performing different image processing on each of the first and second regions determined as the region of the copy-forgery-inhibited pattern image in the copy-forgery-inhibited pattern region determination step and the other regions, and the image processing step The tint block region determination method according to claim 11, further comprising a printing step of printing image data on which image processing has been performed.
(21) A tint block area determination program for causing a computer of an image forming apparatus to execute the tint block area determining method by the image forming apparatus according to any one of items 1 to 20.

  According to the inventions described in (1) and (11) above, when the image forming apparatus receives image data created by an external apparatus and composed of a document image and a tint block image, the received image data to be printed is received. On the other hand, it is determined whether or not there is a specific image pattern composed of dot images for each certain area, and the period of the specific image pattern is determined for the area determined to have the specific image pattern. . Further, it is determined whether or not there is a first area whose specific image pattern period is the first period and a second area where the second period is the second period, and the first and second areas exist. In this case, it is determined that these areas are areas of the tint block image, that is, the tint block area.

  That is, since the area of the copy-forgery-inhibited pattern image can be extracted from the image data with the copy-forgery-inhibited pattern image created by the external device, the image forming apparatus can identify the original image and the copy-forgery-inhibited pattern image in the image data. Therefore, since it is possible to perform printing after separately performing image processing for printing a document image and a tint block image, an image forming apparatus capable of outputting a printed matter on which a tint block image intended by a user is printed Become.

  According to the inventions described in (2) and (12) above, the image forming apparatus extracts an area where the density of the specific image pattern is uniform and the density is equal in the area where the specific image pattern is determined to exist. At the same time, since it is determined whether or not the first and second areas are present in the extracted area, it is determined whether or not the area is a copy-forgery-inhibited pattern image. As a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the above items (3) and (13), the image forming apparatus determines the constituent color of the specific image pattern in the area determined to have the specific image pattern, and determines the area having the same constituent color. In addition to the extraction, it is determined whether or not the first and second areas are present in the extracted area, and it is determined whether or not the area is a copy-forgery-inhibited pattern image. As a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the preceding items (4) and (14), the image forming apparatus determines the area gradation of the specific image pattern in the region where it is determined that the specific image pattern exists, and the area gradation is equal. Since the region is extracted and whether or not the first and second regions are present in the extracted region is determined to determine whether the region is the region of the copy-forgery-inhibited pattern image. This can be performed with high accuracy, and as a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the preceding items (5) and (15), the image forming apparatus determines the attribute of the image data for each certain area, and only for the area where the attribute is determined to be a character or a figure. Since it is determined whether or not a specific image pattern exists, it is possible to efficiently determine the area of the tint block image.

  According to the inventions described in the preceding items (6) and (16), when the image forming apparatus determines that the first and second regions exist, the low-frequency cycle of the first cycle and the second cycle. Is determined to be equal to or greater than a certain threshold value, and when it is determined that the low frequency period is equal to or greater than the certain threshold value, the first and second areas are determined to be areas of the tint block image. The image can be identified with higher accuracy, and as a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the above items (7) and (17), when the image forming apparatus determines that the first and second regions exist, the cycle of the first and second regions is a low cycle. If it is further determined whether the region is surrounded by a region having a high cycle, and it is determined that a region having a low cycle is surrounded by a region having a high cycle, the first Since the second area is determined to be the area of the copy-forgery-inhibited pattern image, the original image and the copy-forgery-inhibited pattern image are identified with higher accuracy when the low-frequency copy-forgery-inhibited pattern image is formed in the high-frequency copy-forgery-inhibited pattern background image. As a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the above items (8) and (18), when the image forming apparatus determines that the first and second regions exist, the cycle of the first and second regions is a high cycle. It is further determined whether or not the region is surrounded by a region having a low cycle, and if it is determined that a region having a high cycle is surrounded by a region having a low cycle, the first Since the second area is determined as the area of the copy-forgery-inhibited pattern image, when the high-frequency copy-forgery-inhibited pattern image is formed in the low-frequency copy-forgery-inhibited pattern background image, the document image and the copy-forgery-inhibited pattern image are identified with higher accuracy. As a result, the tint block image intended by the user can be printed more reliably.

  According to the inventions described in the preceding items (9) and (19), when it is determined that the first and second regions exist, the image forming apparatus has a low cycle in the first and second regions. An image of a certain area is set to a single-color solid pattern, image data is created by erasing the image of the area with a high cycle, and the created image data is character-recognized to characterize the region with a low cycle. As a result of determining whether or not a character is formed, if it is determined that characters are formed in an area having a low period, the first and second areas are determined as areas of the copy-forgery-inhibited pattern image. The image and the copy-forgery-inhibited pattern image can be identified with higher accuracy, and as a result, the copy-forgery-inhibited pattern image intended by the user can be printed more reliably.

  According to the inventions described in (10) and (20) above, image data obtained by performing different image processing on the first and second areas determined as the areas of the copy-forgery-inhibited pattern image and the other areas are obtained. Since the printing is performed, the image forming apparatus can output a printed matter on which the tint block image intended by the user is printed.

  According to the invention described in item (21), the tint block area determination method described in any one of items (11) to (19) can be executed by the computer of the image forming apparatus.

1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram of a network system in which the image forming apparatus of FIG. 1 is used. 2 is a block diagram illustrating an internal configuration of the image forming apparatus. FIG. FIG. 4 is a block diagram illustrating a configuration example of a printer image processing module in the image forming apparatus illustrated in FIG. 3. 3 is a diagram illustrating an example of image data with a tint block sent from an external device to the image forming apparatus 1. FIG. FIG. 6 is a diagram illustrating a state where the image data with the tint block shown in FIG. 5 is printed by performing the same image processing as that performed on the original image including the tint block region. It is a flowchart for demonstrating the detection processing method of a tint block image area | region with respect to the image data with a tint block produced with the external device. It is a figure which shows an example of a specific pattern analysis table. 12 is a flowchart illustrating another example of a tint block image area detection processing method for tint block image data created by an external device. It is a flowchart which shows the further another example of the detection processing method of the tint block area | region with respect to image data. 10 is a flowchart illustrating an operation of the image forming apparatus when different image processing is performed in a background pattern area detected by a background pattern area detection processing method and an area other than the background pattern area.

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

  FIG. 1 is a perspective view of an image forming apparatus 1 according to an embodiment of the present invention. In this embodiment, as the image forming apparatus 1, the above-mentioned MFP, which is a multifunction digital multi-function machine having a copy function, a printer function, a scan function, a facsimile function, and the like, is used, and data can be transmitted and received via a network. It is.

  As shown in FIG. 1, the image forming apparatus 1 has a plurality of USB (Universal Serial Bus) insertion ports 20, 21, and 22. By connecting to an external device having a USB interface, both data Transmission / reception is possible. The interface of the removable external storage device is not limited to USB, but the USB interface is adopted in the illustrated example. Various media such as USB memory, USB HDD, CF card, etc. are assumed as the removable external storage device.

  As shown in FIG. 1, the image forming apparatus 1 includes a plurality of keys 11 a, an operation unit 11 that receives various instructions by the user's operation on the keys, and input of data such as characters and numbers, and an instruction menu for the user And a display 12 that displays information about the acquired image, a scanner unit 13 that optically reads a document to obtain image data, and a printer unit 14 that prints an image on a recording sheet based on the image data.

  Further, a feeder unit 17 for feeding a document to the scanner unit 13 is provided on the upper surface of the main body of the image forming apparatus 1, a paper feeding unit 18 for supplying a recording sheet to the printer unit 14 is provided at the lower part, and a printer unit 14 is provided at the central part. A tray 19 from which a recording sheet on which an image is printed is ejected, and a detection sensor 19a that detects the presence or absence of the recording sheet, and a communication unit 16 that transmits and receives image data and the like with an external device via a network, and image data The memory | storage part 23 which memorize | stores etc. is provided. Although not shown, the image forming apparatus has a network interface, and the communication unit 16 is connected to the network via the network interface so that various types of data can be transmitted to and received from external devices. ing.

  The communication unit 16 transmits / receives facsimile data via a public telephone line, and transmits / receives data to / from an external device connected to the network via a network such as a LAN or the Internet. To do. As a result, the image forming apparatus has not only a function as a facsimile apparatus that performs normal facsimile communication but also a function as an e-mail transmission / reception terminal. Therefore, various image data can be transmitted and received as an attached file of an e-mail. Note that network communication performed by the image forming apparatus may be wired or wireless.

  The display 12 is used for various displays including a list display of data transmission destinations. The operation unit 11 is used for various inputs including selection of a transmission destination by the user. These function as the main part of the user interface.

  Further, a human body detection device 30 for detecting a user is provided on the front surface of the main body of the image forming apparatus 1. As the human body detection device 30, various devices such as detection by an image from an image captured by an infrared sensor or a camera are assumed.

  The scanner unit 13 acquires image data by photoelectrically reading image information such as photographs, characters, and pictures from a document. The acquired image data (density data) is converted into digital data by an image processing unit (not shown), subjected to various kinds of known image processing, and then sent to the printer unit 14 and the communication unit 16 for image printing and data. Or is stored in the storage unit 23 for later use.

  The printer unit 14 prints an image on a recording sheet based on image data acquired by the scanner unit 13, image data received from an external device by the communication unit 16, or image data stored in the storage unit 23.

  FIG. 2 is a configuration diagram of a network system in which the image forming apparatus 1 of FIG. 1 is used. The image forming apparatus 1 is connected to a network 5 by one or a plurality of PCs 2 and 3 by wire or wirelessly via an access point 4. The user issues a print instruction for image data created by the applications of the PCs 2 and 3 to the image forming apparatus 1 via the network 5, and the image forming apparatus 1 that has received the print instruction can print the designated image data. Yes.

  FIG. 3 is a block diagram showing the internal configuration of the image forming apparatus 1. As shown in FIG. 3, the image forming apparatus 1 operates the CPU 101 that performs overall control of the entire image forming apparatus 1, the RAM 102 that is a work area when the CPU 101 operates, the additional RAM 119, and the CPU 101. ROM 118 for storing data such as a program for executing the program, a storage device 103 including a hard disk device (HDD), an operation panel 104 for operating the image forming apparatus 1, a network module 105 for performing network communication, and a surface of a document The first scanner 107 and the second scanner 113 for reading the back side and the back side, and the first and second scanner image processing modules for processing the image data of the originals read by the first scanner 107 and the second scanner 113, respectively. 108 and 114, and each scanner image processing module 108 114, first to third image control modules 109, 115, 117 for compressing and decompressing images processed by the external controller interface module 116, and a printer image processing module for processing image data to be printed 110, a printer 111 that prints image data processed by the printer image processing module 110, a FAX controller 112 that performs facsimile (FAX) communication, a USB interface module 106 for connecting to a USB device, a PC, and the like A wireless communication module 120 for wirelessly communicating with an external terminal is provided. The wireless technology employed in the wireless communication module 120 may be wireless LAN, Bluetooth (registered trademark), or the like, but is not limited thereto.

  FIG. 4 is a block diagram illustrating a configuration example of the printer image processing module 110 in the image forming apparatus 1 illustrated in FIG. 3. In this embodiment, the printer image processing module 110 includes a background pattern area detection unit 201 that detects a background pattern image area (background pattern area) of image data to be printed. The tint block area detection unit 201 may be configured as a part of the function of the CPU 101. Different image processing is executed for the background pattern area detected by the background pattern area detection unit 201 and the area other than the background pattern area.

  Specifically, for areas other than the tint block area, the first image correction processing unit 202 performs first sharpness processing, smoothing processing, and first color correction processing, and then the screen processing unit 204 performs screen processing. The first line width correction processing is performed by the first line width correction processing unit 205 after the screen processing.

  On the other hand, when the copy-forgery-inhibited pattern area detection unit 201 detects a copy-forgery-inhibited pattern area, the second image correction processing unit 203 performs the second sharpness process and the second color correction process on the copy-forgery-inhibited pattern area. The second line width correction processing unit 206 performs the second line width correction process without performing the screen process.

  In this way, the image data with a tint block on which different image processing is performed in the tint block region and the non-ground pattern region is then printed by the printer 111.

  Image data with a background pattern from which the background pattern area is detected by the background pattern area detection unit 201 is created by an external device other than the image forming apparatus 1, for example, the PCs 2 and 3, and the image forming apparatus 1 via the network 5 Image data may be received, or image data stored in a USB memory, USB HDD, CF card, or the like may be received via the USB interface 105 or the like.

  FIG. 5 shows an example of image data 300 with a background pattern sent from the PCs 2 and 3 to the image forming apparatus 1. The image data 300 includes a document image portion 301 composed of characters “SAMPLE”, a tint block latent image region 302a composed of characters “COPY”, and a tint block background region 302b arranged so as to surround the tint block latent image region 302a. Yes. A tint block area 302 is composed of the tint block latent image area 302a and the tint block background area 302b.

  In FIG. 5, as shown in P2 by enlarging a part P1 of the image data, the copy-forgery-inhibited pattern latent image region 302a and the copy-forgery-inhibited pattern background region 302b are both from a specific dot pattern (halftone dot) in which a large number of dots are arranged. It is configured. In this embodiment, the dots in the tint block latent image area 302a are larger in size than the dots in the tint block background area 302b, and the interval between the dots is set wider. That is, the dot cycle of the dot pattern is set to be low in the tint block latent image region 302a (low cycle) and high in the tint block background region 302b (high cycle). Note that the dot size and the dot pattern cycle may be reversed in the background pattern latent image area 302a and the background pattern background area 302b.

  When the image data with the tint block shown in FIG. 5 is printed by performing the same image processing as that performed on the original image including the tint block region, the tint block background region 302b disappears as shown in FIG. 302a becomes a manifested printed material, and a printed material intended by the user cannot be obtained.

  A background pattern image area detection processing method by the background pattern area detection unit 201 for image data with a background pattern created by an external apparatus will be described with reference to the flowchart of FIG. The processing shown in this flowchart and the flowcharts of FIG. 9 and the subsequent steps are specifically executed by the CPU 101 of the image forming apparatus 1 operating according to an operation program stored in the ROM 118 or the like. This detection process is performed in units of one page, and is performed by dividing one page into regions of a certain pixel range.

  In step S101, all parameters of the specific pattern analysis table are set to zero and initialized. FIG. 8 shows an example of the specific pattern analysis table. The specific pattern analysis table has parameters of density, period, constituent color, area gradation, primary determination, and secondary determination for each region of a certain pixel range to which region numbers are assigned.

  Then, the following determination is performed for each fixed region. First, in step S102, it is determined whether or not a specific image pattern (specific dot pattern) (hereinafter also referred to as a specific pattern) exists in a certain area. If not (NO in step S102), a specific pattern analysis is performed in step S103. Both “non-halftone dots” are set in the primary determination and secondary determination parameters of the table. This result is shown in the table of FIG. It corresponds to 1. No. For the region 1, the subsequent steps are not processed.

  If it is determined in step S102 that the specific pattern exists (YES in step S102), halftone dots are set as the primary determination parameters in the specific pattern analysis table in step S104. As a result, the area No. in the table of FIG. It corresponds to 2-9.

  Next, in step S105, it is determined whether or not the density of the specific pattern is uniform. If not (NO in step S105), "halftone" is set in the secondary determination parameter of the specific pattern analysis table in step S106. This result is shown in FIG. It corresponds to 2. No. For the area 2, the subsequent steps are not processed.

  If the density is uniform in step S105 (YES in step S105), the density value is set in the density parameter of the specific pattern analysis table in step S107. In step S108, the period of the specific pattern is determined, and the determination result is set in the period parameter of the specific pattern analysis table. There are two cycles in the boundary area between the tint block latent image area 302a and the tint block background area 302b, but one of them may be adopted.

  Further, after determining the color of the specific pattern in step S109 and setting the determination result in the parameter of the constituent color of the specific pattern analysis table, the area gradation of the specific pattern is determined in step S110, and the area level of the specific pattern analysis table is determined. Set the judgment result in the key parameter.

  Next, in step S111, it is checked whether or not the processing for one page has been completed. If it has not been completed (NO in step S111), the process returns to step S102, and steps S102 to S110 are repeated for the next area.

  When the processing for one page is completed (YES in step S111), in step S112, a region in which the secondary determination parameter of the specific pattern analysis table is 0 and the density, component color, and area gradation parameters are equal to each other is determined. Extract. The secondary determination parameter of the specific pattern analysis table is 0 at the stage of executing this processing because the area No. in the table of FIG. It corresponds to 3-9.

  The region where the parameters of density, component color, and area gradation are the same is not only a region where the values of the parameters are completely the same, but also a region where the values are approximated and approximately the same considering the measurement error. Is also included. It may be determined that the parameters are equal if the difference between the regions for each parameter is within a preset fixed range.

  In step S113, as a result of the extraction in step S112, it is checked whether or not there is a region where the secondary determination parameter of the specific pattern analysis table is 0 and the density, constituent color, and area gradation parameters are equal. If it does not exist (NO in step S113), in step S114, "halftone dots" are set for all of the specific pattern analysis table whose secondary determination parameters are 0. The area subjected to this processing is the area No. in the table of FIG. 5-No. 7.

  When there are regions having the same density, component color, and area gradation parameters (YES in step S113), two or more extracted regions exist, and the period of these regions is 2 in step S115. Judge whether the type. If there are two types of cycles (YES in step S115), the region is a tint block region. The two types of cycles are compared.

  In this embodiment, since the cycle of the specific pattern of the tint block latent image region 302a is lower than the cycle of the specific pattern of the tint block background region 302b, in step S117, the secondary determination of the specific pattern analysis table is performed for the low cycle region. Set the “background tint latent image” to the parameter of. On the other hand, in step S118, “background pattern background” is set in the secondary determination of the specific pattern analysis table for the high cycle region. In the table of FIG. 3 and no. No. 4 area and No. 4 8 and no. 9 regions. No. 3 and no. No. 4 area and No. 4 8 and no. Nine areas are areas of different tint block images.

  In step S115, if the cycle is one type or more than three types, “halftone dot” is set as the secondary determination parameter in the specific pattern analysis table in step S116.

  Next, in step S119, it is checked whether or not there is an area where the secondary determination parameter in the specific pattern analysis table is 0. If it exists (YES in step S119), the process returns to step S112 until it does not exist. Steps S112 to S119 are repeated. In the table of FIG. 3 and no. 4 is first extracted to determine whether it is a tint block image area, and in steps S112 to S119, No. 4 is determined. 8 and no. Nine areas are extracted, and it is determined whether the area is a tint block image area. When there is no area where the parameter for secondary determination is 0 (NO in step S119), the process ends.

  As described above, with the method of detecting the tint block area described in the flowchart of FIG. 7, “non-halftone dot”, “halftone dot”, “latent tint latent image”, “ It can be classified into four areas of “background pattern background”. The area of “background pattern latent image” and “background pattern background” is the background pattern area 302.

  In addition, as a result of determining whether or not there are two types of periods in step S115, if there are two types of periods (YES in step S115), the period of the lower period is equal to or greater than a predetermined threshold value. It is also possible to determine whether the area is a tint block area when it is further determined whether the area is equal to or greater than a certain threshold value. This is because, in the case of a cycle smaller than a certain threshold value, it is possible to determine that the pattern is not a tint block because the dot interval is too large to exhibit the tint block function.

  FIG. 9 is a flowchart illustrating another example of a method for detecting a tint block area for image data with a tint block created by an external device. In this example, step S201 is implemented between step S101 and step S102 shown in FIG. Note that the same processes as those in the flowchart of FIG. 7 are denoted by the same step numbers as in FIG.

  That is, in step S101, all values in the specific pattern analysis table are initialized by setting them to zero. Then, in step S201, it is determined whether or not the image attribute of a certain area is a character or an image (graphic). If the image attribute of the certain area is a character or an image (graphic) (YES in step S201), the process proceeds to step S102, and it is determined whether or not a specific pattern exists in the certain area. If the image attribute of the certain area is not a character or an image (graphic) (NO in step S201), in other words, if it is a photograph or the like, a background pattern is not generally added to the photo area. Both “non-halftone dots” are set in the primary determination and secondary determination parameters of the analysis table.

  After step S201, steps S102 to S111 are performed in the same manner as in the detection method of FIG. 7. In step S111, it is checked whether or not the processing for one page has been completed. NO), the process returns to step S201, and steps S301 to S110 are repeated for the next region.

  When the processing for one page is completed (YES in step S111), steps S112 to S119 are performed as in the detection method of FIG.

  In this way, the attribute of the image data is determined for each fixed area, and it is determined whether or not the specific pattern exists only for the area where the attribute is determined to be a character or an image (figure). A region that is not a character or image (graphic) and is clearly not a tint block region is determined as a non-halftone dot, and it is not determined whether or not a specific pattern exists, so that the tint block region detection process can be performed efficiently. it can.

  In the embodiment of FIGS. 7 and 9, it is determined whether or not the density of the specific pattern is uniform in step S105. If the density is uniform in step S107, the density is set in the specific pattern analysis table, and the specific pattern is determined in step S109. Are determined and set in the specific pattern analysis table. In step S110, the area gradation of the specific pattern is determined and set in the specific pattern analysis table. In step S112, the density, the configuration color, and the area gradation are determined. An area with the same is extracted to determine whether it is a tint block area.

  However, it is not always necessary to analyze the density, constituent color, and area gradation, and at least the period of the specific pattern may be determined. Further, it may be configured to determine at least one of density, constituent color, and area gradation in addition to the period determination. By determining at least one of density, component color, and area gradation, the determination accuracy of the background pattern region can be improved, and by determining the combination of two of density, component color, and area gradation, the background pattern The determination accuracy of the region can be further improved, and the accuracy can be further improved by determining all of the density, the constituent color, and the area gradation as in the embodiment of FIGS.

  FIG. 10 is a flowchart showing still another example of a tint block region detection processing method for image data to be printed.

  In step S301, primary detection processing is executed. This primary detection process is the same as the detection process shown in the flowchart of FIG.

  In this embodiment, as a result of the detection processing in step S301, the background pattern background region in which the background pattern latent image region 302a having a specific pattern cycle of a low cycle is a high cycle in the region determined as a background pattern latent image or a background pattern background. It is further determined whether or not it is surrounded by 302b. As shown in FIG. 5, if the copy-forgery-inhibited pattern background image region 302 a having a low cycle is surrounded by a copy-forgery-inhibited pattern background region 302 b having a high cycle, these regions can be determined as the copy-forgery-inhibited pattern region 302. is there.

  That is, in step S302, it is determined whether or not the X-coordinate minimum value of the tint block latent image area is larger than the X-coordinate minimum value of the tint block background area (YES in step S302). It is determined whether the X coordinate maximum value is smaller than the X coordinate maximum value of the tint block background area. If the X coordinate maximum value of the tint block latent image area is smaller than the X coordinate maximum value of the tint block background area (YES in step S303), the Y coordinate minimum value of the tint block latent image area is the Y coordinate minimum value of the tint block background area in step S304. Determine if greater than. If the minimum Y coordinate value of the tint block latent image area is greater than the minimum Y coordinate value of the tint block background area (YES in step S304), the maximum Y coordinate value of the tint block latent image area is the maximum Y coordinate value of the tint block background area in step S305. Determine if less than. If the maximum Y coordinate value of the tint block latent image area is smaller than the maximum Y coordinate value of the tint block background area (YES in step S305), it is determined that the tint block latent image area is surrounded by the tint block background area, and the tint block latent image The background pattern area is determined to be a background pattern area, and the “background pattern latent image” and the “background pattern background” set in the secondary determination parameters of the specific pattern analysis table are maintained as they are.

  In other cases, that is, when the X coordinate minimum value of the tint block latent image area is not larger than the X coordinate minimum value of the tint block background area (NO in step S302), the X coordinate maximum value of the tint block latent image area is X of the tint block background area. If not smaller than the coordinate maximum value (NO in step S303), if the Y coordinate minimum value of the tint block latent image area is not larger than the Y coordinate minimum value of the tint block background area (NO in step S304), the Y coordinate of the tint block latent image area If the maximum value is not smaller than the Y coordinate maximum value of the background pattern background area (NO in step S305), it is not the background pattern area. Therefore, in step S306, the “background pattern latent image” set as the secondary determination parameter in the specific pattern analysis table. ”And“ background pattern background ”are all changed to“ halftone dots ”.

  As described above, in the embodiment described with reference to FIG. 10, for the area determined to be the tint block latent image or the tint block background, the tint block latent image region having the low period of the specific pattern is the tint block background region having the high cycle. Since it is further determined whether or not the image is surrounded by the document image, the original image and the copy-forgery-inhibited pattern image can be identified with higher accuracy, and as a result, the copy-forgery-inhibited pattern image intended by the user can be printed more reliably.

  When the period of the specific pattern of the tint block latent image area 302a is higher than the period of the tint block background area 302b, the copy-forgery-inhibited pattern latent image area having a high cycle has a low period, contrary to the process shown in FIG. It may be determined whether or not it is surrounded by a periodic background pattern background area, and if it is surrounded, these areas may be determined as a background pattern area.

  Next, during printing, an image when different image processing is performed on the tint block area detected by the tint block area detection processing method described with reference to the flowcharts of FIGS. 7, 9, and 10 and other areas other than the tint block area The operation of the forming apparatus 1 will be described with reference to the flowchart of FIG.

  When printing is started, the tint block region detection processing described in FIG. 7, FIG. 9, or FIG. 10 is performed in step S401. As a result, in step S402, the parameters for secondary determination in the specific pattern analysis table are checked, and the area where the parameter is “non-halftone” (step S403) and the area where it is “halftone” (step S404). On the other hand, in step S407, first sharpness processing, first smoothing processing, and first color correction processing are performed as first image correction processing, and then screen processing is performed in step S408, and further in step S409. A first line width correction process is performed. For the area where the secondary determination parameter in the specific pattern analysis table is the “background pattern latent image” (step S405) and the area where the background pattern was “background pattern background” (step S406), the second image is displayed in step S410. As the correction process, the second sharpness process and the second color correction process are performed, and then the second line width correction process is performed in step S411. Thereafter, the image processed image data is printed.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, as a result of the detection process in step S301 in FIG. 10, the image of the tint block latent image region in which the cycle of the specific pattern is a low cycle is set as a single-color solid pattern for the region determined as the tint block latent image or the tint block background. Image data obtained by erasing an image of a certain background pattern background area may be created, and the created image data may be subjected to character recognition processing to determine whether or not a character is formed in an area having a low cycle. As a result, if it is determined that characters are formed in the tint block latent image area, it is considered that the function is being performed as a tint block pattern. The region may be determined. With such a configuration, the document image and the tint block image can be identified with higher accuracy.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2, 3 Personal computer 5 Network 101 CPU
DESCRIPTION OF SYMBOLS 110 Image processing module for printer 111 Printer 201 Background pattern detection part 300 Image data with a background pattern 301 Original image 302 Background pattern image 302a Background pattern latent image area 302b Background pattern background area

Claims (21)

Accepting means for accepting printing of image data created by an external device and composed of a manuscript image and a tint block image;
Image pattern determination means for determining whether or not there is a specific image pattern composed of dot images for each predetermined region for the image data to be printed received by the reception means;
A period determining means for determining a period of a specific image pattern for an area determined by the image pattern determining means to have a specific image pattern;
It is determined whether there is a first region in which the cycle of the specific image pattern determined by the cycle determination unit is the first cycle and a second region in which the second cycle is the second cycle. A copy-forgery-inhibited pattern region determination unit that determines a region formed by the first and second regions as a copy-forgery-inhibited pattern image region when a second region exists;
An image forming apparatus comprising: A density determination means for determining whether or not the density of the specific image pattern in the region where it is determined that the specific image pattern exists;
The copy-forgery-inhibited pattern area determining means extracts areas in which the density of the specific image pattern is determined to be uniform and the density is equal by the density determining means, and the first and second areas are extracted from the extracted areas. The image forming apparatus according to claim 1, wherein the image forming apparatus determines whether the image exists. The apparatus further includes a configuration color determination unit that determines a configuration color of the specific image pattern in an area where it is determined that the specific image pattern exists.
The copy-forgery-inhibited pattern area determination unit extracts an area having the same configuration color of the specific image pattern determined by the configuration color determination unit, and whether or not the first and second areas exist in the extracted area The image forming apparatus according to claim 1, wherein: Area gradation determination means for determining the area gradation of the specific image pattern in the region where it is determined that the specific image pattern exists,
The copy-forgery-inhibited pattern determination unit extracts a region having the same area gradation of the specific image pattern determined by the area gradation determination unit, and the first and second regions exist in the extracted region. The image forming apparatus according to claim 1, wherein the image forming apparatus determines whether or not. Attribute determination means for determining an attribute of the image data for each of the certain areas;
The image pattern determination unit determines whether or not a specific image pattern exists only for an area where the attribute determination unit determines that the attribute of the image data is a character or a graphic. The image forming apparatus according to any one of the above.   When it is determined that the first and second areas exist, the copy-forgery-inhibited pattern area determination unit further determines whether or not the low frequency period is equal to or greater than a certain threshold value among the first period and the second period, The image forming apparatus according to claim 1, wherein when it is determined that the frequency period is equal to or greater than a certain threshold value, the first and second areas are determined as areas of a tint block image.   When it is determined that the first and second areas are present, the area having the low period is surrounded by the area having the high period among the first and second areas. And when it is determined that a region having a low cycle is surrounded by a region having a high cycle, the first and second regions are determined as regions of the tint block image. Item 7. The image forming apparatus according to any one of Items 1 to 6.   When determining that the first and second areas exist, the tint block area determining unit surrounds the first and second areas having a high cycle period in the low cycle period. And when it is determined that a region with a high cycle is surrounded by a region with a low cycle, the first and second regions are determined as regions of the tint block image. Item 7. The image forming apparatus according to any one of Items 1 to 6. When it is determined by the tint block region determining means that the first and second regions exist, an image of a region having a low cycle among the first and second regions is set as a monochromatic solid pattern, and the cycle is a high cycle. Image data creating means for creating image data in which an image in a certain area is erased;
Character recognition means for performing character recognition processing on the image data created by the image data creation means, and determining whether or not a character is formed in a region having a low cycle;
Further comprising
2. The copy-forgery-inhibited pattern region determination unit determines that the first and second regions are regions of a copy-forgery-inhibited pattern image when it is determined by the character recognition unit that a character is formed in a region having a low cycle. The image forming apparatus according to any one of 8 to 8. Image processing means for performing different image processing on the first and second areas determined as the areas of the copy-forgery-inhibited pattern image by the copy-forgery-inhibited pattern area determination means and the other areas;
Printing means for printing image data subjected to image processing by the image processing means;
The image forming apparatus according to claim 1, further comprising: An accepting step for accepting printing of image data created by an external device and composed of a manuscript image and a tint block image;
An image pattern determination step for determining whether or not a specific image pattern composed of dot images exists for each predetermined area for the image data to be printed received by the reception step;
A period determining step for determining a period of a specific image pattern for an area determined to have a specific image pattern by the image pattern determining step;
Determining whether there is a first region in which the cycle of the specific image pattern determined in the cycle determination step is a first cycle and a second region in which the second cycle is a second cycle; A copy-forgery-inhibited pattern region determining step for determining a region formed by the first and second regions as a copy-forgery-inhibited pattern image region when a second region exists;
A tint block region determination method using an image forming apparatus. A density determination step of determining whether or not the density of the specific image pattern in the region where the specific image pattern is determined to exist is uniform;
In the copy-forgery-inhibited pattern area determination step, the density determination step determines that the density of the specific image pattern is uniform and the areas having the same density are extracted, and the first and second areas are extracted from the extracted areas. The tint block region determination method according to claim 11, wherein it is determined whether or not it exists. A composition color determining step for determining a component color of the specific image pattern in the region where it is determined that the specific image pattern exists;
In the copy-forgery-inhibited pattern area determining step, an area having the same constituent color of the specific image pattern determined in the constituent color determining step is extracted, and whether or not the first and second areas exist in the extracted area The tint block region determination method according to claim 11 or 12, wherein the determination is made. An area gradation determination step for determining the area gradation of the specific image pattern in the region where it is determined that the specific image pattern exists;
In the copy-forgery-inhibited pattern area determination step, an area having the same area gradation of the specific image pattern determined in the area gradation determination step is extracted, and the first and second areas exist in the extracted area. The tint block region determination method according to claim 11, wherein whether or not the pattern is determined is determined. An attribute determination step of determining an attribute of the image data for each of the predetermined areas;
15. The image pattern determination step determines whether or not a specific image pattern exists only in a region where the attribute determination step determines that the attribute of the image data is a character or a graphic. The tint block region determination method according to any one of the above.   In the copy-forgery-inhibited pattern area determination step, when it is determined that the first and second areas exist, it is further determined whether or not the low frequency period of the first period and the second period is greater than or equal to a certain threshold value. The tint block region determination method according to claim 11, wherein when it is determined that the frequency period is equal to or greater than a certain threshold value, the first and second regions are determined to be tint block image regions.   In the copy-forgery-inhibited pattern area determining step, when it is determined that the first and second areas exist, the area having a low period among the first and second areas is surrounded by the area having a high period. And when it is determined that a region having a low cycle is surrounded by a region having a high cycle, the first and second regions are determined as regions of the tint block image. Item 17. The tint block region determination method according to any one of Items 11 to 16.   In the copy-forgery-inhibited pattern area determining step, when it is determined that the first and second areas exist, the area having a high period among the first and second areas is surrounded by the area having a low period. And when it is determined that a region with a high cycle is surrounded by a region with a low cycle, the first and second regions are determined as regions of the tint block image. Item 17. The tint block region determination method according to any one of Items 11 to 16. When it is determined that the first and second areas exist in the tint block area determination step, an image of an area having a low period among the first and second areas is set as a monochromatic solid pattern, and the period is a high period. An image data creation step for creating image data in which an image in a certain area is erased;
Character recognition processing for character recognition processing of the image data created by the image data creation step to determine whether or not a character is formed in a region having a low cycle;
Further comprising
12. When it is determined by the character recognition step that characters are formed in an area having a low period, the first and second areas are determined as areas of a tint block image in the tint block area determining step. The tint block area determination method according to any one of -18. An image processing step for performing different image processing on the first and second regions determined as the region of the copy-forgery-inhibited pattern image and the other regions determined by the copy-forgery-inhibited region determination step;
A printing step for printing the image data subjected to the image processing in the image processing step;
The tint block area determination method according to claim 11, further comprising:   A program for determining a tint block area for causing a computer of an image forming apparatus to execute the tint block area determining method by the image forming apparatus according to any one of claims 1 to 20.

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