JP2011234193A - Image processing device, image processing method, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly determine attributes even when a small colored image is astride small areas.SOLUTION: When identifying the attributes of the small area, the surrounding portion of the same is included in a range to be identified. A frame line 601 surrounding a small area (4, 3) is set to be the range to be determined, so that even when the colored image is astride two small areas, the continuous length of a colored pixel 501 reaches a predetermined length. This allows the colored image to be identified as a colored original.

Description

  The present invention relates to an image processing apparatus, an image processing method, a program, and a recording medium that read an original, determine attributes of original images such as a color original and a monochrome original, and perform different processes.

  A full-color image forming process in a color copying machine is performed by executing a process of four colors of cyan (C), magenta (M), yellow (Y), and black (Bk), copying on a single transfer sheet, and monochrome. When the copy mode process is executed, an image of one color is copied onto the transfer paper in one process. Since the amount of toner used and the cost of copying differ between full color mode and single color mode, the user must be careful to switch between color mode and single color mode, and operate the mode appropriately according to the type of document. There must be.

  In order to eliminate the hassle of switching modes, a technology that automatically identifies whether a document is a chromatic or achromatic document and automatically switches the operation mode of the copier according to the identification result (automatic color selection: ACS) ) However, when the ACS determination is incorrect, especially when a black and white original is erroneously determined as a chromatic original, it is printed in the four versions of CMYBk, which is not only different from the image desired by the user, but also increases the cost required for copying. Since processing time is also required, highly accurate determination is required.

  A color copier is not a single unit, but is fused with a facsimile function, a printer function, a distribution scanner function, and the like, and is called a multi function printer (MFP). When the MFP is used as a distribution scanner, brightness information is required for a monochrome document. However, if this is mistakenly determined as a color document, color information is required. As a result, the file size increases and the capacity of the HDD drive of the PC is compressed.

  The MFP is equipped with a large-capacity storage medium, and can store images scanned once or images input from other media. These stored images can be read out again and reused for different purposes from the time of storage. For example, if an image scanned by the scanner and transmitted by the distribution scanner function is stored in the HDD, the image can be distributed to another place or read out again without reading the document again by the scanner. Furthermore, it is possible to copy at the same magnification during the first scan, and then output the same document as a 200% enlarged copy image.

  By the way, in image area separation processing such as character / picture separation and document recognition such as color / monochrome document determination, filter processing, color correction processing, and γ are performed in order to switch processing so as to perform appropriate processing according to the recognition result. Perform before processing. For example, in Patent Document 1, image data and its accompanying information (for example, image area separation results) are accumulated so that the user can reuse the image data. In Patent Document 2, ACS determination results and their images are accumulated. Stored on the device.

  The ACS function described above is a function necessary for eliminating the troublesome mode switching even when image data is reused. The ACS determination result is stored as supplementary information of the stored image. However, if the use of the image is different between the image storage and the reuse, the stored ACS determination result is what the user intends. It will be different. This will be described below.

  Consider a case where the color / monochrome mixed original shown in FIG. 5A is copied onto a transfer sheet having the same size as the original. FIGS. 5B, 5C, and 5D are images of transfer paper that are output when copying at the same magnification, 200% enlargement, and 50% reduction, respectively. Since the color area of the original in FIG. 5A is biased to a specific area, no color image exists on the transfer paper in FIG. 5C. In such a case, the ACS determination must be determined as monochrome from the viewpoint of the user.

  Further, even when the same size copy is made with respect to the original in FIG. 5A, when copying is made on a transfer paper smaller than the original (for example, when an A3 size original is copied on A4 transfer paper), FIG. As shown in (e), there may be no color image on the transfer paper. Even in such a case, the ACS determination must be determined to be monochrome.

  The same applies when the MFP is used as a distribution scanner device. When the size of the image distribution file is specified to be smaller than the original, even if there is a color area on the original, the image data distributed to the user will be in color. The area does not exist. In that case, the ACS determination must be determined to be monochrome, assuming that the user needs only a monochrome portion and has specified a small size as the distribution image size.

  As described above, the ACS determination range may be an area corresponding to the output image, not the entire input image. If the user's application is different between image storage and reuse, for example, when copying an A3 size document onto an A3 size transfer paper, the image is first stored at the same time as copying at the same time. In the case of 200% enlargement copy, at the same magnification copy, the entire original is within the ACS determination target range, is determined as a color original, and is stored in the HDD together with the determination result. When a 200% enlarged copy is output in the ACS mode at the time of reuse, it is output in four versions of CMYK even though it is a monochrome image on paper output, and both cost and time are wasted. In order to avoid this, the inside of the dotted line 401 in FIG. However, considering a wide variety of uses at the time of reuse, even if an ACS determination result corresponding to only 200% scaling is accumulated, a problem occurs when copying at the same magnification.

  In the above-mentioned Patent Document 1, a plurality of sets of image data and determination results are held, and a set of image data and determination results corresponding to a large number of reuse forms are held. Even in this case, an image corresponding to all the variable magnifications that can be specified for one document is held, and an extremely large capacity HDD drive is required.

  Therefore, a method that can flexibly cope with various uses of the user at the time of reuse will be described with reference to FIGS. As shown in FIG. 6A, the image area at the time of image accumulation is subdivided into small areas, and ACS determination is performed with each of the small areas as a determination range. FIG. 6B shows the result when C is determined when the small area in FIG. 6A is determined to be color, and N when the small area is determined as monochrome. Set the determination range and determination result for each small area, save a plurality of sets in the HDD, and selectively use the determination result for each small area according to the output range of the image to obtain the ACS determination result of the output image. Ask. For example, if all the results of the small areas included in the output range are achromatic, the ACS determination result of the output image is monochrome, and otherwise, the color is determined. In the example of FIG. 6B, if even one C exists in the output range, the output image is determined to be color, and if no C exists, the output image is determined to be monochrome. When the enlargement / reduction ratio is 200%, the black hatched portion 402 in FIG. 6C is an output image area. However, all the small areas included in this range are determined to be monochrome, and therefore the output image is determined to be monochrome. The

  However, in the case where the ACS determination of the small area is performed using the divided small area as the ACS determination range, there are the following problems when a small chromatic image exists over the small area. That is, as shown in FIG. 7A, an example in which short thin color lines 501 and 502 exist over two areas will be described.

  In the ACS determination, there are several criteria for determining a color original. For example, when the chromatic area is continuous by pixels corresponding to 6 mm (about 144 pixels at 600 dpi), the color is determined to be chromatic. In this case, even if the length of the short color thin line is 8 mm, if it exists across two small areas by 4 mm, each small area is determined to be monochrome, and therefore the entire output image is determined to be a monochrome document. When exactly the same thin color lines 503 and 504 are slightly shifted and exist in a small area (for example, FIG. 7B), the result of the ACS determination in the small area is color, and the output image is determined to be a color original. As described above, even if the document contents are substantially the same (FIGS. 7A and 7B), the ACS determination result varies depending on the positions of the short thin color lines (501 to 504).

  Conventionally, when judging in units of originals, it is determined that there is a continuous portion of 6 mm chromatic pixels in the original, and it is determined as a color original and a color image is output (in this case, however, reusability as described above) Low ACS determination result is accumulated).

  In the ACS determination, as another criterion for determining a color document, it is determined that the pixel is chromatic when a predetermined ratio or more of chromatic pixels are present within a certain area. Even in this criterion, in the example of FIG. Each of the small areas is determined to be monochrome, and in the example of FIG. 7B, since there are many chromatic pixels in the small area and it is determined to be color, there is a similar problem.

The present invention has been made in view of the above problems,
An object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a recording medium that can appropriately determine an attribute of a document image even when a small chromatic image exists over a small area.

  Another object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a recording medium with improved determination accuracy by not referring to an area outside the determination range as a whole document even if the vicinity of the attention area is referred to. Is to provide.

  Another object of the present invention is to provide an image processing apparatus, an image processing method, and an image processing apparatus, in which determination accuracy is improved by changing a method of referring to a peripheral region in a region that does not contact a boundary of a determination range as a whole document. It is to provide a program and a recording medium.

  Still another object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a recording medium that can perform appropriate attribute determination even at the time of reuse and save the cost, time, and capacity of a PC storage device. There is.

  The present invention provides an image processing apparatus comprising: an attribute determination unit that determines an attribute of a document image; and a storage unit that stores an attribute determination result for each determination target area of the document image. The most important feature is that the attribute is determined with reference to the determination target region and its neighboring region.

  According to the present invention, an attribute can be accurately determined even when a small chromatic image exists over a small area in a document image.

1 shows an overall configuration of an image processing apparatus (MFP) according to the present invention. 2 shows a configuration example of a first image processing unit in FIG. 1. An example of a reference chart is shown. 2 shows a configuration example of a second image processing unit in FIG. 1. It is a figure explaining the subject of a prior art. It is a figure explaining the subject of a prior art. It is a figure explaining the subject of a prior art. It is a figure explaining the determination method of Example 1. FIG. It is a figure explaining the determination method of Example 2. FIG. It is a figure explaining the determination method of Example 3, 4. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the overall configuration of an image processing apparatus (MFP) according to the present invention. As shown in FIG. 1, the MFP includes a reading device 101, a first image processing unit 102, a bus control device 103, a second image data processing unit 104, an HDD 105, a CPU 106, a memory 107, Plotter I / F device 108, plotter device 109, operation display device 110, line I / F device 111, external I / F device 112, S.P. B. 113, ROM 114, general-purpose bus 115, and the like. This MFP is configured to be able to perform data communication with an external device such as a FAX 116, a PC 117, and an external medium 118.

  The reading device 101 includes a line sensor composed of a CCD photoelectric conversion element, an A / D converter, and a drive circuit thereof. Based on the density information of the original obtained by scanning the set original, the 8-bit RGB digital data is obtained. Image data is generated and output to the first image processing unit 102. In this embodiment, the reading resolution is 600 dpi, but the resolution is not limited to this.

  The first image processing unit 102 performs processing for unifying the digital image data input from the reading device 101 to a predetermined characteristic and outputs the digital image data. The image data having the unified characteristics is stored inside the image processing apparatus, and is output with characteristics suitable for changing the output destination when reused thereafter.

  The bus control device 103 is a data bus control device that transmits and receives various data such as image data and control commands necessary in the image processing device, and has a bridge function between a plurality of types of bus standards. In this embodiment, the bus control device 103 is connected to the first image processing unit 102, the second image processing unit 104, and the CPU 106 via a PCI-Express bus, and is connected to the HDD 105 via an ATA bus. It has become.

  The second image processing unit 104 performs image processing suitable for an output destination designated by the user on the digital image data whose characteristics predetermined by the first image processing unit 102 are unified, and outputs the digital image data. The HDD (storage device) 105 is a large-sized storage device for storing electronic data that is also used in a desktop personal computer, and mainly stores digital image data and accompanying information of the digital image data. . In this embodiment, as the HDD 105, for example, an ATA bus connection hard disk standardized by expanding IDE can be used.

  The CPU 106 is a microprocessor that controls the entire control of the image processing apparatus. In this embodiment, an integrated CPU in which a + α function is added to a CPU core that has been widely used in recent years can be used. It is possible to use a CPU in which these bus connection functions using the CPU are integrated. The CPU 106 controls reading / writing of the HDD 105 and detects the remaining capacity of the HDD 105 and the like.

  A memory 107 temporarily stores data in order to absorb a speed difference when bridging between a plurality of types of bus standards and a processing speed difference between connected components themselves, and the CPU 106 controls the image processing apparatus. It is a volatile memory that temporarily stores programs and intermediate processing data when performing the above. Since high speed processing is required, the CPU 106 starts up the system with a boot program stored in the ROM 114 during normal startup, and thereafter performs processing with a program developed in a memory accessible at high speed. In the present embodiment, a standardized DIMM used in a personal computer can be used as the memory 107.

  When the plotter I / F device 108 receives the CMYK digital image data sent via the general-purpose standard I / F integrated with the CPU 107, the plotter I / F device 108 performs a bus bridge process for outputting to the dedicated I / F of the plotter device 109. Do. In the present embodiment, for example, a PCI-Express bus can be used as the general-purpose standard I / F.

  When the plotter device 109 receives the digital image data composed of CMYK, the plotter device 109 outputs the received image data on the transfer paper using an electrophotographic process using a laser beam. S. B. Reference numeral 113 denotes one of chip sets used for a personal computer, which is a general-purpose electronic device called South Bridge. S. B. Reference numeral 113 denotes a bus bridge function often used in constructing a CPU system mainly including PCI-Express and an ISA bridge, and bridges the ROM 114. The ROM 114 is a memory that stores a program (including a boot program) used when the CPU 106 controls the MFP.

  The operation display device 110 is a part that performs an interface between the MFP and the user, and is composed of an LCD (Liquid Crystal Display) and a key switch. Detect. In this embodiment, the CPU 106 is connected via a PCI-Express bus. The line I / F device 111 is a device that connects a PCI-Express bus and a telephone line, and transmits and receives various data via the telephone line. A FAX 116 is a normal facsimile, and transmits / receives image data to / from the MFP via a telephone line. The external I / F device 112 is a device that connects a PCI-Express bus and an external device, and this device enables the image processing apparatus (MFP) to exchange various data with the external device. In this embodiment, a network (Ethernet (registered trademark)) is used for the connection I / F. That is, the MFP is connected to the network via the external I / F device 112. A PC 117 is a personal computer, and a user performs various controls and input / output of image data with respect to an image processing apparatus (MFP) via installed application software and drivers.

(Copy operation)
An outline of the copy operation of the image processing apparatus having the above configuration will be described. The user sets an original on the reading apparatus 101, and performs setting of a desired mode and the like, input of copy start, enlargement / reduction ratio, transfer paper size setting, and the like using the operation display device 110. The operation display device 110 converts information (copy mode or the like) input from the user into control command data inside the device and issues it. The issued control command data is notified to the CPU 106 via the PCI-Express bus.

  The CPU 106 executes a copy operation process program in accordance with the copy start control command data, and executes settings and operations necessary for the copy operation. The operation process is described below.

  First, RGB 8-bit digital image data (hereinafter referred to as RGB image data) obtained by scanning a document with the reading device 101 is unified to characteristics predetermined by the first image processing unit 102, and the bus control device 103. Sent to. As will be described later, the first image processing unit 102 performs ACS determination, and information including a determination range and a determination result together with image data is transmitted together with other auxiliary information (image region separation result and the like). It is done.

  The bus control device 103 stores the RGB image data input from the first image processing unit 102 in the memory 107 via the CPU 106. The RGB image data and supplementary information stored in the memory 107 are sent to the second image processing unit 104 via the CPU 106 and the bus control device 103.

  The second image processing unit 104 converts the received RGB image data into CMYK image data for plotter output, and outputs the converted data to the bus control device 103. However, when the black-and-white copy mode is designated as the copy mode, or when the black-and-white document is determined in the ACS mode, it is converted to K single-color image data instead of CMYK image data and output to the bus control device 103. The bus control device 103 stores the CMYK or K single color image data input from the second image processing unit 104 in the memory 107 via the CPU 106.

  Next, the CMYK or K monochrome image data stored in the memory 107 is sent to the plotter device 109 via the CPU 106 and the plotter I / F device 108. The plotter device 109 outputs the received CMYK or K monochrome image data to a transfer sheet, and a copy of the document is generated.

(Scanner delivery operation)
An outline of the scanner distribution operation of the image processing apparatus (MFP) configured as described above will be described. First, the user sets a document on the reading device 101, and performs setting of a desired mode and the like and input of scanner distribution start using the operation display device 110. Here, the resolution of the distribution image, the range to be read, etc. are specified. The operation display device 110 converts information input by the user into control command data inside the device and issues it. The issued control command data is notified to the CPU 106 via the PCI-Express bus.

  The CPU 106 executes a scanner distribution operation process program according to the scanner distribution start control command data, and sequentially performs settings and operations necessary for the scanner distribution operation. The operation process will be described in order below.

  The RGB image data obtained by scanning the original with the reading device 101 is unified with predetermined characteristics by the first image processing unit 102 and sent to the bus control device 103. As will be described later, the first image processing unit 102 performs ACS determination, and information including a determination range and a determination result together with image data is transmitted together with other auxiliary information (image region separation result and the like). It is done. The bus control device 103 stores the RGB image data input from the first image processing unit 102 in the memory 107 via the CPU 106. The RGB image data and supplementary information stored in the memory 107 are sent to the second image processing unit 104 via the CPU 106 and the bus control device 103.

  The second image processing unit 104 converts the input RGB image data into scanner delivery image data (RGB multi-value, gray scale, monochrome binary, etc.) and outputs the image data to the bus control device 103. Particularly in the ACS mode, if it is determined to be a color document, it is converted to RGB multi-value image data and JPEG compression is performed. If a monochrome document is determined, it is converted to a monochrome binary image and then MMR compression is performed. To generate a TIFF file. If it is determined that the document is a monochrome document, it may be converted into a grayscale multilevel image and JPEG compression may be performed.

  The bus control device 103 stores the image data and incidental information input from the second image processing unit 102 in the memory 107 via the CPU 106. The image data stored in the memory 107 is sent to the external I / F device 112 via the CPU 106. The external I / F device 112 transmits input image data to a PC 117 connected via a network. At this time, the incidental information does not need to be transmitted together with the image data. However, in response to the ACS determination result, information indicating whether the document is a color document or a monochrome document may be written and transmitted in the header information of the image file. .

(Image accumulation operation)
The image processing apparatus (MFP) can perform only image storage without performing a copy operation or a scanner distribution operation. An outline of the operation will be described. First, the user sets a document on the reading device 101, and performs setting of a desired mode or the like and an instruction for image reading using the operation display device 110. When image accumulation is performed, reading is performed under general-purpose conditions so that the image can be reused for various purposes after accumulation. That is, the entire original is always read at the same magnification. The operation display device 110 converts information input by the user into control command data inside the device and issues it. The issued control command data is notified to the CPU 106 via the PCI-Express bus. The CPU 106 executes a program for an image accumulation operation process in accordance with control command data for starting image accumulation, and sequentially performs settings and operations necessary for the image accumulation operation. The operation process will be described in order below.

  The RGB image data obtained by scanning the original with the reading device 101 is unified with predetermined characteristics by the first image processing unit 102 and sent to the bus control device 103. As will be described later, the first image processing unit 102 performs ACS determination, and information including a determination range and a determination result together with image data is transmitted together with other auxiliary information (image region separation result and the like). It is done. When the bus control device 103 receives RGB image data and incidental information input from the first image processing unit 102, they are stored in the HDD 105.

(Copy operation / scanner distribution operation + image storage operation)
The image processing apparatus can simultaneously perform a copy operation and an image storage operation. In the copy operation, the bus control device 103 accumulates RGB image data input from the first image processing unit 102 in the memory 107 via the CPU 106. The RGB image data and supplementary information stored in the memory 107 are sent to the second image processing unit 104 via the CPU 106 and the bus control device 103. At this time, the same RGB image data and incidental information sent to the memory 107 via the CPU 106 are sent to the HDD 105 via the CPU 106 and the bus control device 103 and stored in the HDD 105. As a result, the copy operation and the image accumulation operation can be performed simultaneously. Similarly, in the case of a scanner distribution operation, RGB image data and incidental information input from the first image processing unit 102 are sent to the memory and stored in the HDD 105 via the CPU 106 and the bus control device 103. As a result, the scanner delivery operation and the image storage operation can be performed simultaneously.

(Reuse of stored images)
The image data and supplementary information stored in the image processing apparatus (MFP) can be reused even when time has elapsed since the image was stored. An outline of the operation at the time of reuse will be described. First, the user confirms what kind of images are accumulated from the operation display device 110. The operation display device 110 has a function of displaying the file name, date / time, and thumbnail image of images stored at the time of browsing, and can be confirmed by the user. The user selects an image to be reused, and further performs setting input such as a desired mode by the operation display device 110. Here, paper output or electronic file scanner delivery can be selected. In addition, it is possible to reuse the function provided by the MFP such as FAX transmission.

  If the reuse is scanner distribution of an electronic file, as described in the scanner distribution processing, the user designates the resolution of the distribution image, the range to be read, and the like by the operation display device 110. The operation display device 110 converts information input by the user into control command data inside the device and issues it. The issued control command data is notified to the CPU 106 via the PCI-Express bus. The CPU 106 executes a scanner distribution operation process program according to the scanner distribution start control command data at the time of reuse, and sequentially performs settings and operations necessary for the scanner distribution operation. The operation process will be described in order below.

  At the time of reuse, since the data that has been processed by the first image processing unit 102 is accumulated, the CPU 106 sends an instruction to read the corresponding image data to the bus control device 103. The bus control device 103 sends the RGB image data and supplementary information read from the HDD 105 to the second image processing unit 102 via the CPU 106. The subsequent processing is the same as that at the time of scanner distribution described above.

  Here, an example in which accumulated data is reused for scanner delivery has been described, but it can also be reused for paper output. In that case, the flow is almost the same as the reuse for scanner delivery described above. The processing after being sent to the second image processing unit 102 is the same as that at the time of copying described above.

  The above-described problem occurs when the copy operation / scanner distribution operation + image storage operation or reuse is performed after the image storage operation. Here, details of the copy operation + image storage operation will be described.

The user sets an original on the reading device 101, and performs an operation display device 110 to set a desired mode and the like, input a copy start, enlargement / reduction magnification, transfer paper size setting image, and the like. The operation display device 110 converts information (copy mode or the like) input from the user into control command data inside the device and issues it. Here, it is set so that an A3 size original is copied to an A3 size transfer sheet at the same magnification in the ACS mode. The issued control command data is notified to the CPU 106 via the PCI-Express bus. The CPU 106 executes a copy operation process program in accordance with the copy start control command data, and executes settings and operations necessary for the copy operation. The operation process is described below.
As described above, RGB image data obtained by scanning a document with the reading device 101 is converted into predetermined characteristics by the first image processing unit 102 and sent to the bus control device 103.

  FIG. 2 shows a configuration example of the first image processing unit 102 in FIG. As shown in FIG. 2, the first image processing unit 102 includes an image area separation unit 201, a color document determination unit 202, a γ conversion unit 203, a filter processing unit 204, a color conversion processing unit 205, and an image compression unit 206. ing.

  The image area separation unit 201 discriminates the character / picture area and chromatic / achromatic area of the document based on the RGB image data input from the reading device 101, and outputs the image area separation result to the filter processing unit 204. To do. The color document determination unit 202 determines whether the document is a color document or a monochrome document. As a determination method in the image area separation unit 201 and the color document determination unit 202, for example, a determination method described in Patent Document 3 may be used.

  The ACS determination target range will be described. Here, since the A3 size original is set to be copied at the same magnification on the A3 size transfer sheet, the ACS determination range is the entire original. In the prior art, the color / monochrome mixed document shown in FIG. 5A is determined to be in color. In the prior art, the determination result is stored together with the image data. However, the determination unit 202 of the present invention subdivides the determination target region and stores the position information and the determination result of each region. An appropriate determination range and a determination result thereof are read out when being reused, and an output image determination result is determined. The appropriate determination range is determined according to the output image area. In other words, at the time when the output image area is stored without being determined, it is not determined whether the stored image is a color document or a monochrome document, so the image processing apparatus (MFP) may output it. It is necessary to store the ACS determination result in a state that can cope with all of the certain states.

  Specifically, the entire reading range is subdivided into regions as indicated by dotted lines in FIG. 6A, and an attribute that is an ACS determination result is assigned to each small region. However, as described later, the determination range of the ACS determination does not necessarily match the size of the small area. The result of performing the ACS determination in the predetermined determination range is set as the determination result of the image in the small area. The determination result for each small area is stored together with the position information indicating the determination target area together with the image data. Note that a known method may be used as the ACS determination method. For example, using the technique of Patent Document 4, it is determined whether the corresponding area is a color original by looking at the continuity of chromatic pixels, and referring to the upper left, upper, upper right, and left pixels, Is determined to be a color document when the continuous amount of the image is a predetermined number or more.

  Next, the determination range for the small area will be described with reference to an example of the original in FIG. Of the regions subdivided in FIG. 7A, the Xth cell from the left and the Yth cell from the top are (X, Y), and the upper left cell is the origin (1, 1). The 8 mm color thin line 501 extending over (4, 3) and (5, 3) belongs to each of the two squares by 4 mm.

  As an ACS determination example of this embodiment, it is assumed that a color document is determined when 6 mm chromatic pixels are continuous. In this case, when the ACS determination range of each small area is made to coincide with the small area, since there is only a continuous area of 4 mm chromatic pixels in each area, the small areas (4, 3), (5, 3) are It is determined to be monochrome. As a result, although there is actually a chromatic pixel of 8 mm, it does not coincide with the judgment standard of a color document (6 mm chromatic pixels are continuous).

  In the present invention, when determining the attributes of a small area, the peripheral area is included in the determination range. In FIG. 8A, a frame line 601 around the small region (4, 3) is a determination range, and FIG. 8B is an enlarged view thereof. In this way, the above-described problem can be solved by setting the determination range including the periphery of the small region. In the above example, if the determination range is 2 mm around the small area (4, 3), the continuous length of the chromatic pixels 501 reaches 6 mm, so that it can be determined as a chromatic original. In addition to the image shown in FIG. 7A, it is sufficient to add 6 mm to the determination range in order to make an appropriate determination when the chromatic image extends even over a plurality of small areas.

  When a color original is determined when the continuous length of chromatic pixels is equal to or greater than Lc, it is sufficient to set an extra determination range only for the peripheral area Lc of the small area. When one is determined to be a color document, an extra determination range may be provided for the periphery Lc / 2 of the small area.

  In the above-described determination method, the determination range for the small region to be determined is set larger than the small region, but the obtained determination result is attributed only to the original small region. By having a plurality of overlapping determination ranges in this way, it is possible to appropriately determine even when a small chromatic image exists across a plurality of small areas.

  Returning to FIG. 2, the γ conversion unit 203 unifies the brightness of the RGB image data input from the reading device 101 to a predetermined characteristic and outputs the data to the filter processing unit 204. In the present embodiment, for example, the lightness is converted into a linear characteristic. The filter processing unit 204 unifies the input RGB image data with a predetermined characteristic and outputs the data to the color conversion processing unit 205.

  In the present embodiment, for example, when a reference chart as shown in FIG. 3 is scanned, conversion is performed so that an MTF characteristic value predetermined for each number of lines is obtained. Further, when correcting the MTF characteristic value, since the required characteristic value is different between the character part and the picture part, correction is performed for each of the character part / picture part. Therefore, an appropriate filter process is performed according to the character / picture discrimination result discriminated by the image area separation unit 201.

  The color conversion processing unit 205 unifies the input RGB image data with a predetermined characteristic and outputs the data to the image compression unit 206. In the present embodiment, for example, conversion is performed so that the color space becomes the Adobe (registered trademark) -RGB color space. The image compression unit 206 compresses the RGB image data after color conversion processing by changing the compression rate based on the additional information (remaining capacity information) of the HDD 105 input from the CPU 106 via the bus control device 103. Generate image data.

  When the bus control device 103 receives the image data and the accompanying information (image area separation result and ACS determination result) from the first image processing unit 102, the bus control device 103 accumulates them in the memory 107 via the CPU 106. The data stored in the memory 107 is transmitted to the HDD 105 via the CPU 106 and the bus control device 103 and stored / stored in the HDD 105. Thereafter, as described above, the RGB image data in the memory 106 is subjected to image processing by the second image processing unit 104 and then output to the plotter device 109 to generate a copy of the document, but in the ACS mode. In this case, before the image data is sent to the second image processing unit 104, the CPU 106 determines whether the corresponding image is a color document or a monochrome document, and the processing of the second image processing unit 104 is performed. Switch.

  The CPU 106 refers to a plurality of ACS determination ranges and determination results from information attached to one image. At this time, since the image area to be output by the image processing apparatus is determined, only those included in the range are referred to. If any one of them is determined to be in color, it is determined that the document is a color document. Therefore, in the same size copy, all stored determination ranges and determination results are referred to, and it is determined as a color original. Note that the image area output by the image processing apparatus is determined by the scaling factor and transfer paper size specified by the user when the MFP is used as a copying apparatus, and by the resolution and reading designation area when used as a distribution scanner apparatus. It is determined.

  Next, the operation of the second image processing unit will be described in detail. FIG. 4A shows a configuration example of the second image processing unit 104 in FIG. As shown in FIG. 4A, the second image processing unit 104 includes an image expansion unit 301, a filter processing unit 302, a color conversion processing unit 303, a resolution conversion unit 304, a γ conversion unit 305, and a halftone processing unit 306. , And a format conversion unit 307. The image expansion unit 301 expands the image compressed by the first image processing unit 102.

  The filter processing unit 302 corrects the sharpness of the RGB image data so that the reproducibility when output to the plotter device 109 is improved. Specifically, a sharpening / smoothing process is performed with reference to an image area separation result which is supplementary information of the image data. For example, emphasis processing is performed in order to make the character clear and improve legibility in the character region, and smoothing processing is performed in the pattern region to smooth the image. The filter processing unit 204 in the first image processing unit 102 performs conversion so as to obtain a predetermined MTF characteristic value for each number of lines in order to improve reusability, whereas the second image processing unit A filter processing unit 302 in 104 performs processing for performing processing according to a user's output application (paper output, electronic output). For example, when the user designates the character mode as the image quality mode, the degree of enhancement processing is increased, and when the user designates the photo mode, processing for increasing the degree of smoothing processing is performed.

  When receiving RGB 8-bit image data, the color conversion processing unit 303 converts CMYK 8-bit image data, which is a color space for the plotter device 109, or K-monochromatic 8-bit image data. In the ACS mode, if it is determined to be a color document, it is converted to CMYK image data, and if it is determined to be a monochrome document, it is converted to K single color.

  The resolution conversion unit 304 converts the resolution when enlarging / reducing the image. The γ conversion unit 305 converts the gradation characteristics of the image according to the characteristics of the output destination to which the image is output. When copying through the plotter device 109, the gradation of the output image can be kept good. Thus, the conversion is performed in consideration of the output characteristics of the plotter 109. When the halftone processing unit 306 receives CMYK 8-bit image data or K-monochromatic 8-bit image data, the halftone processing unit 306 performs gradation number conversion processing according to the gradation processing capability of the plotter device 109. For example, the number of gradations is converted into CMYK or K 2-bit image data using an error diffusion method which is one of pseudo halftone processing. In the case of outputting a multi-value image, the halftone processing unit 306 does not perform processing. The format conversion unit 307 performs JPEG compression, MMR compression, or the like according to the application, or creates a PDF file, but sends image data to the subsequent stage without performing any processing during paper output.

  As described above, the first image processing unit 102 unifies the characteristics of the image data so that the image data input from the reading apparatus 101 can be used for both the plotter apparatus 109 and the external apparatus, and the characteristics are improved. The unified image data is stored in the HDD 105, and the second image processing unit 104 processes the image data with characteristics suitable for the output of the plotter device 109 and the external device, so that the user can store the image data inside the image processing device (MFP). When outputting the stored / stored image data, the image data can be output to an application different from the application used when storing / saving the image data in the image processing apparatus. In the above description, the same-size copy + accumulation operation is performed, and as described above, the attributes (color document, monochrome document) of the image stored without determining the output image area are not determined, and the output image When the area is determined, the ACS determination result of the output image can be determined.

  Subsequently, when the accumulated image is reused and the paper is output at 200% magnification, the user confirms the accumulated image on the operation display device 110. The operation display device 110 has a function of displaying the file name, date / time, and thumbnail image of images stored at the time of browsing. The user selects an image to be reused and displays an input of desired mode setting and the like. This is performed by the apparatus 110. Here, in the ACS mode, a setting is made to output the paper at 200% magnification on the A3 size transfer paper. When the previously accumulated image data is output and it is decided to output the paper on an A3 size transfer paper with 200% enlargement, the image area output by the image processing apparatus is determined. In this example, since the hatched portion 402 in FIG. 6C is output, the ACS determination refers only to the determination result of the small area included in the hatched portion 402. Since only the image determined to be monochrome is in the small area of the hatched portion 402, it is finally determined to be a monochrome document.

  As described above, by subdividing the data into a plurality of determination ranges and the respective determination results, the data is stored, and the ACS determination result of the output image is determined when the image region output by the image processing apparatus is determined. It is possible to perform ACS determination appropriately corresponding to various reuse modes. In this embodiment, an example is shown in which the subdivision is divided into 8 in the main scanning direction and 10 in the sub-scanning direction, but the number of divisions is not limited to this. In addition, the smaller the determination range is, the more various types of reuse can be handled. However, the smaller the determination range, the larger the capacity of the HDD that stores the determination range and determination result set is required. A lot of processing time is required for the ACS determination range and the determination result. Therefore, the operation display device 110 may allow the user to select the number of divisions. For example, in the above example, (number of main scanning divisions, number of sub-scanning divisions) = (8, 10), but the user uses the operation display device 110 to change this to (4, 5), (6, 8), ( 8, 10), (16, 20), (32, 40) may be selected in five stages. When the user selects and accumulates it, the first image processing unit 102 subdivides the determination target area, and determines the degree of subdivision when storing each position information and determination result as necessary. Can be changed. This makes it possible to appropriately change the correspondence to the reuse mode according to the processing time when the stored image is reused in the ACS mode and the capacity of the HDD drive. The number of divisions that can be selected is not limited to the above example.

  In the second embodiment, when a part of the document is cut out as the image output area, the outside of the output image area is out of the determination range. That is, in Example 2, even if a color region is included outside the ACS determination range, it is not determined as a color.

  For example, when the rectangular area having the range indicated by the thick line 602 in FIG. 9A, the small area (2, 3) at the upper left, and the small area (6, 7) at the lower right is cut out and reused, the image output range The outside is outside the ACS determination range.

  In the first embodiment, as shown in FIG. 9B, the attribute determination range of the small area (6, 3) is within the frame line 601 extending over the eight small areas in the vicinity of the small area. However, the right and upper sides of the small area (6, 3) are outside the output image range, and the area outside the determination range is included in the determination range. It is not appropriate to count the color pixels 505 outside the determination range as the continuous length of the chromatic pixels, and it is better not to refer to the surrounding area when determining the attribute of the small area. Therefore, for the region indicated by 603 in FIG. 9D (region including the peripheral portion of the output image), the result of matching the range of the small region in which the attribute is accumulated with the determination range is used. For the other image output areas, as shown in the first embodiment, when determining the attributes of the small area, the determination range uses a result obtained by viewing the vicinity of the small area wide. As a result, the small area (5, 6) in which some of the color pixels 506 are present (FIG. 9C) can be determined as a color document. On the other hand, the small areas (6, 6) in which some of the color pixels 505 exist are determined as monochrome originals. Here, the color line extending over the small areas (5, 6) (6, 6) has a total length of 8 mm and extends over the two areas by 4 mm, and a continuous chromatic original serving as a reference for determining the color original. The length was set to 6 mm.

  As described above, the determination range used for the ACS determination for each small area to be stored differs depending on the positional relationship between the image to be output and the image to be stored. In order to improve the reusability of the stored image, it is necessary to be able to cope with the case where the user cuts out an arbitrary area of the document. For each small region, two types of “ACS determination result in which the size of the small region and the ACS determination range are matched” and “ACS determination result in which the range expanded to the vicinity of the small region is the ACS determination range” are accumulated. The ACS determination result of an appropriate small area can be referred to according to the image range to be output.

  When the user reuses the stored image, the peripheral area of the output image range refers to the “ACS determination result in which the size of the small area and the ACS determination range are matched”, and the small image corresponding to the other image output area. For the region, refer to the “ACS determination result in which the range expanded to the vicinity of the small region is the ACS determination range” as described in the first embodiment. If at least one of these small region ACS determination results is a color document determination, the output image is finally determined to be in color, and otherwise is determined to be monochrome.

  The third embodiment is an embodiment in which the periphery of the document is not included in the determination range. Although the configuration is the same as that of the first embodiment, the periphery of the document is not included in the ACS determination range. Even if the color area is included only in the peripheral area of the document, it is not determined as color. For example, the peripheral area 8 mm of the document is excluded from the ACS determination range. This is because when reading the edge of the document or outside the document area, it may erroneously determine that the monochrome area is color by reading noise components other than the image data. In rare cases, a color area may exist only at the edge of the document. However, when the edge (boundary) of the document is read, there is a problem that a monochrome document is always erroneously determined as a color document.

  For example, when reading an edge of a document or outside the document area, for example, when the document is scanned while being moved by an automatic document feeder (ADF), the document is skewed depending on the transport of the ADF. May be read outside the document area. Further, in the case of a reading method in which a document is fixed and a scanner is operated, even if the user places the document slightly obliquely, the end of the document or outside the document area is read.

  Therefore, the peripheral portion of the document is outside the ACS determination range. In FIG. 10A, the shaded portion 701 around the document is outside the determination range, and pixels outside this range are not counted as continuous pixels of the number of chromatic pixels. For example, the length of the color line 507 existing across the small regions (7, 3) and (8, 3) in FIG. 10 (a) is 6 mm, the inside of (7, 3) is 3 mm, (8, 3) The inside is 3 mm. The vicinity of the small area (7, 3) is shown enlarged in FIG.

  In the first embodiment, the determination range of the small area (7, 3) is shown as a line 702 that extends from the small area (7, 3) to the surrounding eight small areas. In the first embodiment, the small area (7, 3) is determined to be a color. However, when a part of the color line 507 is included in the peripheral area of the original by 1 mm, the determination process is different from that in the first embodiment. This is shown in FIG. In FIG. 10C, since 1 mm on the right side is outside the determination range, it is recognized that the color region is continuous by 5 mm. When the continuous length of chromatic pixels is 6 mm as a reference for color document determination, this is determined to be monochrome.

  As in the first embodiment, by referring to the periphery of each small region, even when the ACS determination accuracy of the small region is increased, the determination in the appropriate determination range can be performed without referring to the outside of the ACS determination range. In this case, when accumulating the ACS determination result belonging to the subdivided area by the first image processing unit 102, the result of the determination outside the ACS determination range is not included in the determination range in advance.

  Note that, as the ACS determination, when it is determined that an original including small color pixels only in the peripheral portion is color, the following processing is performed. That is, chromatic pixels near the boundary of the ACS determination range are counted, and the count is weighted for processing. For example, in a normal area, if a chromatic pixel having a pixel equivalent to 6 mm (144 pixels at 600 dpi) is continuously counted, it is determined as a color document, but if there is a chromatic pixel that touches the boundary of the ACS determination range, 2 pixels equivalent to 2 mm (48 pixels) are added to the count value of the continuous pixels. Therefore, if there is a continuous pixel corresponding to 4 mm (96 pixels) within the determination range, it is determined as a color original. This process assumes that when there is a chromatic pixel near the boundary of the determination range, there is a high probability that color pixels exist continuously outside the determination range. As a result, even if chromatic pixels exist only in the peripheral portion of the document, it can be determined to be a color document to some extent.

  In the embodiment described above, an example of the ACS determination that determines a color document when a predetermined number or more of chromatic pixels are continuous has been described, but the ACS determination is not limited thereto. For example, there is a method of determining a color original when the number of chromatic pixels existing within a predetermined area is greater than a certain ratio. For example, if the number of chromatic pixels existing in the determination target area reaches 5% or more, it is determined as a color original.

Further, there is an example in which even if the ratio of chromatic pixels is insufficient in only a small area, the ratio of determining a color original is reached by referring to the periphery. For example, in FIG. 10D, when Sa is a hatched area and Sb is an area within a line 703 drawn outside the hatched area (508 is a chromatic pixel), in the normal method, a color document is determined. The existence ratio Ci of chromatic pixels used as an index is defined by the following equation.
Ci = (number of chromatic pixels in Sa) / (area of Sa)
On the other hand, in the method of the present invention, the existence ratio Ci ′ of chromatic pixels used as a color original determination index is defined by the following equation.
Ci ′ = (number of chromatic pixels in Sb) / (area of Sa)
By making the denominator coincide with the area of the small region and expanding the reference range Sb of the chromatic pixel more than the small region, it is possible to appropriately determine even the small chromatic region 508 existing across the small region. In the case of the normal method (Ci), even if the criteria for color originals are not met, the method (Ci ′) of the present invention can satisfy the criteria.

  In the first to third embodiments, the CPU 106 determines the color document of the output document with reference to information attached to one image, but the present invention is not limited to this. As shown in FIG. 4B, it may be determined whether or not the output document is a color document (determination made by the CPU 106 in the first embodiment) in the second image processing unit. Further, although the embodiment has been described using ACS determination as an example of document attribute determination, the present invention is, for example, a document type determination that determines any one of a character document, a photographic document, and a mixed character / photograph document as the document type. Is also applicable.

  For example, instead of determining a color document, the output document attribute determination unit 308 performs document type determination. The document type determination is performed in exactly the same manner as the image area separation, and the number of pixels of the character determination result is counted. If the number of pixels is equal to or greater than a predetermined number, the document is determined to be a character document. Further, the number of pixels of the halftone dot determination result is counted, and if the number of pixels is equal to or larger than a predetermined number, it is determined that there are a lot of patterns in the printed document and the photograph document is determined. If both counts are greater than or equal to a predetermined number, it may be determined that the original is a mixed text / photograph. A known method may be used for character determination and halftone dot determination itself.

  Even if the document as a whole satisfies the criterion that it is a character document, but the character exists across a plurality of small areas, it is the same as in the ACS determination that each of the small areas does not satisfy the criterion. In such a case, it is possible to make an appropriate determination by performing document type determination after referring to the peripheral portion of the small area. The present invention can be similarly applied to the determination of the attributes of various originals such as inkjet originals, photographic paper originals, printed originals, copy originals, and map originals, in addition to original type determinations of character originals, photo originals, and mixed character / photo originals.

  Even if the image processing apparatus of the present invention is applied to a system constituted by a plurality of devices (for example, a host computer, an interface device, a scanner, a printer, etc.), the image processing device is applied to an apparatus (host computer, etc.) constituted by one device. It may be applied. Another object of the present invention is to supply a recording medium recording a program code of software for realizing the functions of the above-described image processing apparatus to the system or apparatus, and the computer of the system or apparatus (or CPU, MPU, It can also be achieved by the DSP) executing the program code stored in the recording medium. In this case, the program code read from the recording medium itself realizes the functions of the image processing apparatus described above, and the program code or the recording medium storing the program constitutes the present invention. As a recording medium for supplying the program code, for example, a hard disk, an optical disk, a magneto-optical disk, a nonvolatile memory card, a ROM, or the like can be used. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on an instruction of the program code. A case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included. Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. A case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing is included. Further, the program for realizing the functions and the like of the embodiments of the present invention may be provided from a server by communication via a network.

DESCRIPTION OF SYMBOLS 101 Reading apparatus 102 1st image processing part 103 Bus control apparatus 104 2nd image processing part 105 HDD
106 CPU
107 Memory 108 Plotter I / F Device 109 Plotter Device 110 Operation Display Device 111 Line I / F Device 112 External I / F Device 113 B.
114 ROM
115 General-purpose bus 116 FAX
117 PC
118 External media

JP 2007-251835 A Japanese Patent Laid-Open No. 2002-369012 JP 2003-46772 A Japanese Patent No. 3983101

Claims (10)

  In the image processing apparatus, comprising: an attribute determination unit that determines an attribute of the document image; and a storage unit that stores an attribute determination result for each determination target region of the document image. An image processing apparatus characterized in that an attribute is determined with reference to a neighboring region.   The image processing apparatus according to claim 1, further comprising a dividing unit that divides the document image into a plurality of small areas, wherein the attribute determining unit determines an attribute with reference to the small area and its neighboring area. .   The attribute determining unit determines whether a pixel of the document image is a chromatic pixel or an achromatic pixel, and the reference neighboring region is a region including a chromatic pixel of a predetermined size. The image processing apparatus according to claim 2.   The image processing apparatus according to claim 1, further comprising: a unit that outputs a part of the document image as an output image, wherein the attribute determination unit determines the attribute without referring to a region outside the output image. .   The image processing according to claim 1, wherein the storage unit stores a determination result determined with reference to the determination target region and its vicinity region, and a determination result determined without referring to the vicinity region. apparatus.   The image processing apparatus according to claim 1, wherein the attribute determination unit determines the attribute without referring to a peripheral area of the document image.   2. The image according to claim 1, wherein the attribute determining unit determines the attribute based on a predetermined number of chromatic pixels in the vicinity of the boundary of the determination range when a peripheral region of the document image is set as a determination range. Processing equipment.   In an image processing method, comprising: an attribute determination step for determining an attribute of a document image; and a storage step for storing an attribute determination result for each determination target region of the document image. The attribute determination step includes: An image processing method characterized in that an attribute is determined with reference to a neighboring region.   A program for causing a computer to implement the image processing method according to claim 8.   A computer-readable recording medium on which a program for causing a computer to implement the image processing method according to claim 8 is recorded.

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