JP2011061376A - Image processor, image processing method, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily distinguish information on an original color image from a printed monochromatic image, when printing the color image as a monochromatic image in an image processing technology. <P>SOLUTION: When a color image is acquired, a control unit 102 identifies a character area and a photograph area from the color image acquired. The control unit 102 converts areas (graph areas) other than the identified character area and photograph area into monochromatic patterns different by hue area. Then, the control unit 102 outputs a printing command to a printing section 108, so that it prints the image data converted into a pattern, together with image data monochrome-converted in areas other than pattern conversion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing technique for printing a color image as a monochrome image, and to an image processing apparatus, an image processing method, and an image processing program therefor.

  Conventionally, when a color image is printed as a monochrome image, only the lightness (density) of the three color elements (lightness, saturation, and hue) becomes information, and the hue may not be distinguished. This is because even if the colors are different in saturation and hue, they are printed as the same color (density) if the density is the same.

  In order to prevent this, an image processing technique for converting a color with a different hue into a density based on the hue is known (for example, see Patent Documents 1 and 2).

JP 2005-124172 A JP 2007-96391 A

  However, in the image processing techniques described in Patent Documents 1 and 2, monochrome printed images can be differentiated only by density, and thus the number of densities that can be recognized with the naked eye is limited. For example, as in the graphs and legends (explanation) shown in FIGS. 14 and 15, for color images 500 and 510 that need to distinguish the same density (hue) at a distant position, only density conversion is performed based on the hue. Then, it becomes more difficult to distinguish between monochrome printed images 520 and 530 shown in FIGS.

  The present invention has been made in view of the above-described circumstances. When a color image is printed as a monochrome image, the image processing apparatus and image which make it easy to distinguish information of the original color image from the printed monochrome image. An object is to provide a processing method and an image processing program.

  In order to achieve the above object, the present inventor, when printing a color image as a monochrome image, replaces each hue of the color image with a different monochrome pattern, so that the original color image is changed from the printed monochrome image. I thought that it would be easier to distinguish the information.

  The specific invention based on this idea is as follows.

  An image processing apparatus according to a first aspect of the present invention includes an acquisition unit for acquiring color image data, and an identification unit for identifying a character region and a photographic region from the color image data acquired by the acquisition unit. Pattern conversion means for converting areas other than the character area and photo area identified by the identification means into different monochrome patterns for each hue area, and image data pattern-converted by the pattern conversion means Printing means for printing together with image data that has been monochrome-converted in an area other than pattern conversion.

  In the above configuration, when a color image is acquired, a character area and a photograph area are identified from the color image. The areas other than the identified character area and photograph area (graph area) are converted into different monochrome patterns for each hue area. The pattern-converted image data is printed together with image data that has been subjected to monochrome conversion in an area other than the pattern conversion. Therefore, when a color graph is printed in monochrome, it is converted into a different monochrome pattern, so that the graph printed in monochrome can be easily distinguished.

  In one embodiment, the color image data is data read by an original reading unit, and the image processing apparatus counts for each hue of an area other than a character area and a photographic area to generate a hue frequency distribution. And a hue peak specifying means for specifying a hue having a high frequency based on the frequency distribution of the hue generated by the generating means, and the pattern converting means is provided by the hue peak specifying means. Means for converting each specified hue into a different monochrome pattern is included.

  According to this aspect, when the color image data is data read by a document reading unit such as a scanner, the area other than the character area and the photograph area (graph area) is counted for each hue and the frequency distribution of the hue Is generated. Based on the frequency distribution of the generated hue, a hue having a high frequency (hue that forms a peak) is specified. The identified hue is converted into a monochrome pattern that is different for each hue. Hue other than the specified color is converted into monochrome. Therefore, even color image data read by the document reading unit can be easily distinguished when performing monochrome printing. In particular, by extracting only hues with high frequencies (hues that form peaks), noise extracted due to document stains, etc. is removed, areas with uneven density and uneven colors are recognized as the same color, and a relatively wide range. The hue used in can be converted into a monochrome pattern.

  In another aspect, the color image data is print data sent from an external device for printing, and the image processing device recognizes a color region included in the graph by analyzing the print data. Graph recognition means is further included, and the pattern conversion means includes means for converting each color region recognized by the graph recognition means into a different monochrome pattern.

  According to this aspect, when the color image data is print data sent from an external device such as a personal computer (hereinafter referred to as “PC”), the color included in the graph is analyzed by analyzing the print data. The area is recognized. The recognized color area is converted into a different monochrome pattern for each color area. Therefore, even when the print data is sent from the external device, it is possible to easily distinguish the print data when performing monochrome printing.

  By the way, if the density is close, it is difficult to distinguish when monochrome printing is performed. For this reason, it is necessary to perform pattern conversion only in regions where the density is close and the hue is different.

  Therefore, in the image processing apparatus, the pattern conversion means includes means for converting into different monochrome patterns when there are different hues in a predetermined range of density.

  An image processing method according to the second aspect of the present invention includes an acquisition step for acquiring color image data, and an identification step for identifying a character region and a photographic region from the color image data acquired in the acquisition step. A pattern conversion step for converting regions other than the character region and the photo region identified in the identification step into different monochrome patterns for each hue region, and image data subjected to pattern conversion in the pattern conversion step. And a printing step for printing together with image data converted into monochrome in an area other than the pattern conversion.

  According to the above configuration, when a color graph is printed in monochrome, it is converted into a different monochrome pattern. Therefore, it is easy to distinguish a graph printed in monochrome.

  An image processing program according to a third aspect of the present invention is for an acquisition step for acquiring color image data in a computer, and for identifying a character region and a photographic region from the color image data acquired in the acquisition step. An identification step, a pattern conversion step for converting areas other than the character area and the photograph area identified in the identification step into different monochrome patterns for each hue area, and pattern conversion in the pattern conversion step. And a printing step for printing the image data together with the image data converted into monochrome in an area other than the pattern conversion.

  According to the above configuration, when a monochrome graph is printed, it is converted into a different monochrome pattern, so that it is easy to distinguish the graph printed in monochrome.

  According to the present invention, when a color image is printed as a monochrome image, information of the original color image can be easily distinguished from the printed monochrome image.

1 is a block diagram illustrating a configuration of an image processing apparatus according to a first embodiment of the present invention. It is a figure which shows an example of monochrome pattern data. It is a figure which shows the program structure of the image processing main routine in a flowchart format in case color image data is the data read by the original reading part. It is a figure which shows the program structure of the monochrome conversion process as an image processing subroutine in case color image data is the data read by the original reading part in a flowchart format. It is a figure which shows an example of hue frequency distribution. It is a figure which shows the program structure of an image processing routine in case a color image data is PDL data sent from PC in a flowchart format. It is a figure which shows the printing output image at the time of printing the color image shown in FIG. 14 with a monochrome image using the method of this invention. It is a figure which shows the printing output image at the time of printing the color image shown in FIG. 15 with a monochrome image using the method of this invention. It is a block diagram which shows the structure of the image processing apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the concept of density scale data. It is a figure which shows the program structure of the monochrome conversion process as an image processing subroutine in case color image data is the data read by the original reading part in a flowchart format. It is a figure which shows an example of density-hue frequency distribution. It is a figure which shows the program structure of an image processing routine in case a color image data is PDL data sent from PC in a flowchart format. It is a figure which shows an example of a color image. It is a figure which shows the other example of a color image. It is a figure which shows the printing output image at the time of printing the color image shown in FIG. 14 with a monochrome image using the conventional method. It is a figure which shows the printing output image at the time of printing the color image shown in FIG. 15 with a monochrome image using the conventional method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the drawings attached to this specification, the same reference numerals are assigned to the same functional parts. The names and functions are also the same. Therefore, description thereof will not be repeated.

[First Embodiment]
<Configuration of image processing apparatus>
FIG. 1 is a block diagram showing a configuration of an image processing apparatus 100 according to the first embodiment of the present invention.

  Referring to FIG. 1, an image processing apparatus 100 according to the present embodiment is an MFP (Multi Function Printer), and includes a control unit 102, a document reading unit 104, a memory 106, a printing unit 108, a communication interface (hereinafter, “ Communication 110) and HDD (Hard Disk Drive) 112.

  The control unit 102, document reading unit 104, memory 106, printing unit 108, communication I / F 110, and HDD 112 are each connected to the BUS 114. The communication I / F 110 is connected to the PC 118 via a LAN (Local Area Network) 116.

  The control unit 102 is substantially a computer and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Functionally, the control unit 102 includes an image identification unit 120, a pattern conversion unit 122, a monochrome conversion unit 124, a frequency distribution generation unit 126, a peak identification unit 128, and a graph recognition unit 130.

  The image identification unit 120 identifies a character area and a photograph area from the input (acquired) color image data. Note that the input mode (acquisition mode) of color image data in the image processing apparatus 100 includes a mode by color document scanning in the document reading unit 104 and a PDL (Page Description Language) from the PC 118 via the LAN 116 and the communication I / F 110. It is roughly divided into the mode in which data is input.

  The pattern conversion unit 122 converts regions other than the character region and the photograph region identified by the image identification unit 120, that is, the graph region, into different monochrome patterns for each hue.

  The monochrome conversion unit 124 performs monochrome conversion on an area other than the pattern converted by the pattern conversion unit 122, that is, a character area and a photograph area.

  When the input color image data is data read by the document reading unit 104, the frequency distribution generation unit 126 counts areas (graph areas) other than the character area and the photograph area of the color image data for each hue. To generate a hue frequency distribution. Based on the generated hue frequency distribution, the peak specifying unit 128 specifies a hue having a high frequency, that is, a hue forming a peak. When the hue is specified, the pattern conversion unit 122 converts each of the specified hue areas into a different monochrome pattern.

  On the other hand, when the input color image data is PDL data sent from the PC 118, the graph recognition unit 130 recognizes a color area included in the graph by analyzing the PDL data. When the color area is recognized, the pattern conversion unit 122 converts each recognized color area into a different monochrome pattern.

  The document reading unit 104 includes a scanner. Specifically, the document reading unit 104 includes a CCD (Charge Coupled Device) line sensor, for example, and reads a reflected light image from the document as an RGB (R: red, G: green, B: blue) analog signal. It is configured as follows.

  The memory 106 functions as a working memory or the like of the control unit 102, and is configured by a semiconductor memory such as a flash memory, for example.

  The printing unit 108 includes an image forming unit including, for example, a photosensitive drum, a charger, a laser scanning unit (LSU), a developing unit, a transfer unit, a cleaning unit, and a toner supply unit.

  The HDD 112 has a pattern data storage area 132 for storing monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 shown in FIG.

<Monochrome pattern data>
FIG. 2 is a diagram showing an example of monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154.

  Referring to FIG. 2, monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 is replacement data that is referred to when the above-mentioned pattern conversion unit 122 converts a graph area into a monochrome pattern. However, the patterns (patterns) are different from each other.

<Software configuration>
In the present embodiment, when a color image is printed as a monochrome image, printing is performed by substituting monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 for each hue. The information is programmed so that the information of the original color image can be easily distinguished from the monochrome image.

  More specifically, when a color image is acquired, a character area and a photographic area are identified from the color image, and the areas other than the identified character area and photographic area (graph area) are different for each hue area. It is programmed so that it is converted into a pattern, and this pattern-converted image data is printed together with image data that has been subjected to monochrome conversion in an area other than the pattern conversion.

  This program is configured as software resources for realizing various functions of the image processing apparatus 100 described below, and is stored in the ROM of the control unit 102 which is substantially a computer. These functions are achieved by each functional unit constituting the control unit 102 executing the above program.

(When input color image data is scan data)
FIG. 3 is a flowchart showing the program structure of the image processing main routine in the case where the color image data is data read by the document reading unit 104.

  When the color image data is data read by the document reading unit 104, an area other than a character area and a photograph area (graph area) is counted for each hue to generate a hue frequency distribution. Based on the frequency distribution of hues, hues with high frequencies (hues that form a peak) are identified, and converted into different monochrome patterns for each region of the identified hues.

  Referring to FIG. 3, when color image data is read by document reading unit 104 in step S100, control unit 102 generates pixel data of the read image (step S200).

  When the generation of the image data is completed, the control unit 102 identifies the image data (step S300).

  When the identification of the image data is completed, the control unit 102 performs a monochrome conversion process (step S400). Details of the monochrome conversion process will be described later.

  When the monochrome conversion process ends, the control unit 102 outputs a print command to the print unit 108. In accordance with this command, the printing unit 108 prints a color image as a monochrome image (step S500). As a result, as described later, the color image is replaced with the selected monochrome pattern data and printed out.

(Monochrome conversion processing)
FIG. 4 is a flowchart showing the program structure of a monochrome conversion process as an image processing subroutine when color image data is data read by the original reading unit 104.

  Referring to FIG. 4, in the monochrome conversion process, first, image identification unit 120 determines whether or not a character region is included in the image data as a result of the identification of the image data in step S300 (see FIG. 3). Is determined (step S400A). If a character area is included, the monochrome conversion unit 124 performs monochrome conversion on the character area (step S414A). Thereafter, control proceeds to step S402A. On the other hand, if no character area is included, monochrome conversion is not performed, and control proceeds to step S402A.

  When the control proceeds to step S402A, the image identification unit 120 determines whether the image data includes a photo area as a result of the identification of the image data in step S300. If a photographic area is included, the monochrome conversion unit 124 converts the photographic area into monochrome (step S416A). Thereafter, control proceeds to step S404A. On the other hand, if the photograph area is not included, monochrome conversion is not performed and control proceeds to step S404A.

  When the control proceeds to step S404A, the frequency distribution generation unit 126 generates a hue frequency distribution by counting the regions (graph regions) other than the character region and the photo region identified by the image identification unit 120 for each hue. For example, a frequency distribution of each hue of “red”, “yellow”, and “blue” as shown in FIG. 5 is generated. Thereafter, control proceeds to step S406A.

When the control proceeds to step S406A, the peak specifying unit 128 specifies a hue having a high frequency (hue forming a peak) based on the hue frequency distribution generated by the frequency distribution generating unit 126. For example, in the hue frequency distribution shown in FIG. 5, since any peak of each hue of “red”, “yellow” and “blue” exceeds the threshold value D _TH −1, a peak is formed. The hues that are present are identified as “red”, “yellow” and “blue”. Thereafter, control proceeds to step S408A. The threshold value D _TH -1 can be arbitrarily set.

  When the control proceeds to step S408A, the peak specifying unit 128 notifies the pattern converting unit 122 of the hue forming the peak (hue having a high frequency). For example, in the example illustrated in FIG. 5, three hues of “red”, “yellow”, and “blue” are notified from the peak identifying unit 128 to the pattern conversion unit 122 as the hues that form the peak. Thereafter, control proceeds to step S410A.

  When the control proceeds to step S410A, the pattern conversion unit 122 accesses the pattern data storage area 132 in the HDD 112, and the monochrome pattern data 140, 142, 144, 146, 148, 150 stored in the pattern data storage area 132 is reached. , 152, and 154, monochrome patterns corresponding to the number of hues notified from the peak specifying unit 128 are randomly selected. For example, in the example illustrated in FIG. 5, as described above, three hues of “red”, “yellow”, and “blue” are notified from the peak specifying unit 128 to the pattern conversion unit 122 as the hues that form the peak. Therefore, “three” monochrome pattern data are randomly selected from the monochrome pattern data 140, 142, 144, 146, 148, 150, 152, and 154 in the pattern data storage area 132. Thereafter, control proceeds to step S412A.

  When the control proceeds to step S412A, the pattern conversion unit 122 converts each hue specified as a hue forming a peak in step S406A into monochrome pattern data randomly selected in step S410A. On the other hand, colors other than the notified hue are subjected to monochrome conversion (step S415A). Thereafter, the monochrome conversion process ends.

(When input color image data is PDL data)
FIG. 6 is a flowchart showing the program structure of the image processing routine when the color image data is PDL data sent from the PC 118.

  When the color image data is PDL data sent from the PC 118, the color area included in the graph is recognized by analyzing the PDL data, and each recognized color area is converted into a different monochrome pattern. The

  Here, “PDL” is a language that describes an output image to a printer and instructs the printer when printing a document, an image, or the like created on a computer. When printing a document, it is necessary to convert data such as character and graphic position information and format information into bitmap data. The language for creating this bitmap image is PDL, which can be described without depending on the printer and the resolution of the printer.

  Referring to FIG. 6, when PDL data is acquired from PC 118 via LAN 116 and communication I / F 110 in step S600, control unit 102 outputs a PDL analysis command to graph recognition unit 130. In accordance with this command, the graph recognition unit 130 analyzes the PDL data sent from the PC 118 (step S602).

  When the analysis of the PDL data is completed, the graph recognition unit 130 recognizes the graph based on the analysis result (step S604).

  When the recognition of the graph is completed, the graph recognition unit 130 determines whether there is a region other than the graph, that is, a character region and a photograph region (step S606). If there is an area other than the graph (character area and photo area), the area is developed in monochrome (step S608). Thereafter, control proceeds to step S610. On the other hand, if there is no area other than the graph (character area and photo area), the control jumps to step S610.

  When the control proceeds to step S610, the graph recognition unit 130 recognizes the hue in the graph.

  When the recognition of the hue in the graph is completed, the graph recognition unit 130 performs color development on the graph area (step S612).

  When the development of the graph is completed, the graph recognition unit 130 notifies the recognized hue to the pattern conversion unit 122 (step S614).

  Then, the pattern conversion unit 122 accesses the pattern data storage area 132 in the HDD 112, and among the monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 stored in the pattern data storage area 132. Then, monochrome pattern data of only the lower figure of the hue notified from the graph recognition unit 130 is selected at random (step S616).

  When the pattern selection is completed, the pattern conversion unit 122 converts each hue into monochrome pattern data randomly selected in step S616 (step S618).

  Thereafter, the control unit 102 outputs a print command to the print unit 108. In accordance with this command, the printing unit 108 prints a color image as a monochrome image (step S620). As a result, the color image is replaced with the selected monochrome pattern data and printed out.

<Operation>
When the color image is acquired, the control unit 102 identifies a character area and a photograph area from the acquired color image. The control unit 102 converts the areas (graph areas) other than the identified character area and photo area into different monochrome patterns for each hue area. Thereafter, the control unit 102 outputs a print command to the printing unit 108 to print the image data subjected to the pattern conversion together with the image data subjected to the monochrome conversion in an area other than the pattern conversion.

  At this time, if the acquired color image data is data read by the document reading unit 104, the control unit 102 counts areas (graph areas) other than the character area and the photographic area for each hue. Generate a frequency distribution of. Based on the frequency distribution of the generated hue, the control unit 102 specifies a hue having a high frequency (hue that forms a peak). Then, the control unit 102 converts each specified hue into a different monochrome pattern.

  On the other hand, when the acquired color image data is PDL data sent from the PC 118, the control unit 102 recognizes a color area included in the graph by analyzing the PDL data. Then, the control unit 102 converts each recognized color area into a different monochrome pattern.

<Action and effect>
(1) When a color image is acquired, a character area and a photograph area are identified from the color image. The areas other than the identified character area and photograph area (graph area) are converted into different monochrome patterns for each hue area. The pattern-converted image data is printed together with image data that has been subjected to monochrome conversion in an area other than the pattern conversion. Therefore, when a color graph is printed in monochrome, it is converted into a different monochrome pattern, so that the graph printed in monochrome can be easily distinguished. In particular, as in the graphs shown in FIGS. 14 and 15 and the legend (explanation), regarding the color images 500 and 510 that need to distinguish the same density at a distant position, the color images 500 and 510 are printed as monochrome images. In this case, by replacing each hue with different monochrome pattern data, the graph and the legend can be easily distinguished as in the monochrome print output images 160 and 170 shown in FIGS.

  (2) When the color image data is data read by the document reading unit 104, a region other than the character region and the photograph region (graph region) is counted for each hue to generate a hue frequency distribution. Based on the frequency distribution of the generated hue, a hue having a high frequency (hue that forms a peak) is specified. The identified hue is converted into a monochrome pattern that is different for each area of the hue. Hue other than the specified hue is converted into monochrome. Therefore, even color image data read by the document reading unit can be easily distinguished when performing monochrome printing. In particular, by extracting only hues with high frequency (hues that form peaks), noise extracted due to document stains, etc. is removed, areas with uneven density and uneven colors are recognized as the same color, Widely used hues can be converted to monochrome patterns.

  (3) When the color image data is PDL data sent from the PC 118, the color area included in the graph is recognized by analyzing the PDL data. The recognized color area is converted into a different monochrome pattern for each color area. Therefore, even when the print data is sent from the external device, it is possible to easily distinguish the print data when performing monochrome printing.

[Second Embodiment]
FIG. 9 is a block diagram showing the configuration of the image processing apparatus 100 according to the second embodiment of the present invention.

  The feature of the present embodiment is that when there are different hues in a predetermined range of density, they are converted into different monochrome patterns, and the other configurations are the same as in the first embodiment.

  Therefore, as shown in FIG. 9, in addition to the pattern data storage area 132, the HDD 112 is formed with a scale data storage area 180 for storing the density scale data 192 shown in FIG.

<Structure of scale data>
FIG. 10 is a diagram showing the concept of density scale data 192. As shown in FIG.

  In the example of FIG. 10, the density scale data 192 has a number of scales of “4” and the density is divided into “five” ranges.

<Software configuration>
In the present embodiment, in particular, when the density is close, it is difficult to distinguish when monochrome printing is performed, and therefore, programming is performed so that pattern conversion is performed only in an area where the density is close and the hue is different.

  This program is configured as software resources for realizing various functions of the image processing apparatus 100 described below, and is stored in the ROM of the control unit 102 which is substantially a computer. These functions are achieved by each functional unit constituting the control unit 102 executing the above program.

(Monochrome conversion processing when input color image data is scan data)
FIG. 11 is a flowchart showing the program structure of a monochrome conversion process as an image processing subroutine when color image data is data read by the document reading unit 104. Note that the image processing main routine when color image data is read by the document reading unit 104 is the same as that in the first embodiment, and thus the description thereof is omitted.

  Referring to FIG. 11, in the monochrome conversion process when color image data is read by document reading unit 104, first, image identification unit 120 identifies the image data in step S300 (see FIG. 3). As a result, it is determined whether or not a character area is included in the image data (step S400B). If a character area is included, the monochrome conversion unit 124 performs monochrome conversion on the character area (step S416B). Thereafter, control proceeds to step S402B. On the other hand, if no character area is included, monochrome conversion is not performed, and control proceeds to step S402B.

  When the control proceeds to step S402B, the image identification unit 120 determines whether the image data includes a photo area as a result of the identification of the image data in step S300. If the photograph area is included, the monochrome conversion unit 124 performs monochrome conversion on the photograph area (step S418B). Thereafter, control proceeds to step S404B. On the other hand, if the photograph area is not included, monochrome conversion is not performed and control proceeds to step S404B.

  When the control proceeds to step S404B, the frequency distribution generation unit 126 accesses the scale data storage area 180 in the HDD 112, refers to the density scale data 192 stored in the scale data storage area 180, and based on this reference result. Thus, the hues of the areas (graph areas) other than the character area and the photograph area identified by the image identification unit 120 are counted for each density within a predetermined range determined by the density scale data 192 to generate a density-hue frequency distribution. For example, a density-hue frequency distribution as shown in FIG. 12 is generated. In this example, the number of scales of the density scale data 192 is “3”, and the density range is divided into equal intervals in the “three” ranges of “A”, “B”, and “C”. A hue frequency distribution in the range of density “A”, a hue frequency distribution in the range of density “B”, and a hue frequency distribution in the range of density “C” are generated. Thereafter, control proceeds to step S406B.

When the control proceeds to step S406B, the peak specifying unit 128 specifies a hue having a high frequency (hue forming a peak) based on the hue frequency distribution generated by the frequency distribution generating unit 126. Thereafter, the peak specifying unit 128 determines whether or not there are a plurality of peaks having different hues in a predetermined density range (step S408B). In the density-hue frequency distribution shown in FIG. 12, for example, in the range of density “A”, the peaks of the three hues of “red”, “yellow”, and “blue” exceed the threshold value D _TH -2. Therefore, it is determined that there are a plurality of peaks having different hues in a predetermined density range. Similarly, regarding the density “C” range, two different hue peaks exceed the threshold value D _TH -2, and therefore, it is determined that there are a plurality of peaks having different hues in the predetermined density range. The In this way, when it is determined that there are a plurality of peaks having different hues in the predetermined density range, the control proceeds to step S410B. On the other hand, in the density-hue frequency distribution shown in FIG. 12, for example, in the range of density “B”, there is only one peak exceeding the threshold value D _TH -2, and therefore different hues in a predetermined range of density. It is determined that there are no more than one peak. In this way, when it is determined that there are not a plurality of peaks having different hues in the predetermined density range, the control jumps to step S415B. The threshold value D _TH -2 can be arbitrarily set.

  When the control proceeds to step S410B, the peak specifying unit 128 notifies the pattern converting unit 122 of the hue forming the peak determined to be plural in step S408B. For example, in the example illustrated in FIG. 12, “5” hues are notified from the peak identification unit 128 to the pattern conversion unit 122. Thereafter, the control proceeds to step S412B.

  When the control proceeds to step S412B, the pattern conversion unit 122 accesses the pattern data storage area 132 in the HDD 112, and the monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 stored therein. As many monochrome patterns as the number of hues notified from the peak specifying unit 128 are selected at random. For example, in the example shown in FIG. 12, as described above, “5” is notified from the peak specifying unit 128 to the pattern conversion unit 122 as the number of hues forming the peak. “5” monochrome pattern data are randomly selected from the monochrome pattern data 140, 142, 144, 146, 148, 150, 152, and 154. Thereafter, the control proceeds to step S414B.

  When the control proceeds to step S414B, the pattern conversion unit 122 converts the region of each hue specified as the hue forming the peak in step S408B into the monochrome pattern data randomly selected in step S412B. To do. Thereafter, control proceeds to step S415B.

  In step S415B, monochrome conversion is performed for colors other than the notified hue for each predetermined density range. That is, the hue that has not undergone pattern conversion is converted into monochrome. Thereafter, the monochrome conversion process ends.

  As a result, the color image is replaced with the selected monochrome pattern data and printed out.

(When input color image data is PDL data)
FIG. 13 is a flowchart showing the program structure of the image processing routine when the color image data is PDL data sent from the PC 118.

  Referring to FIG. 13, when PDL data is acquired from PC 118 via LAN 116 and communication I / F 110 in step S <b> 700, control unit 102 outputs a PDL analysis command to graph recognition unit 130. In accordance with this command, the graph recognition unit 130 analyzes the PDL data sent from the PC 118 (step S702).

  When the analysis of the PDL data is completed, the graph recognition unit 130 recognizes the graph based on the analysis result (step S704).

  When the recognition of the graph is completed, the graph recognition unit 130 determines whether there is a region (character region and photo region) other than the graph (step S706). If there is an area other than the graph (character area and photo area), the area is developed in monochrome (step S708). Thereafter, control proceeds to step S710. On the other hand, if there are no areas other than the graph (character area and photo area), the control jumps to step S710.

  When the control proceeds to step S710, the graph recognition unit 130 recognizes the hue and density in the graph.

  When the recognition of the hue and density in the graph is completed, the graph recognition unit 130 performs color development on the graph area (step S712).

  When the development of the graph is completed, the graph recognizing unit 130 determines whether or not there are a plurality of different hues in the predetermined density range with respect to the recognized hue and density (step S714). If it is determined that there are a plurality of different hues in the predetermined density range, the control proceeds to step 716. On the other hand, if it is determined that there are not a plurality of different hues in the predetermined density range, monochrome conversion is performed (step S724), and control jumps to step S722.

  When the control proceeds to step S716, the peak specifying unit 128 notifies the pattern converting unit 122 of the hue determined to have a plurality of peaks having different hues in the predetermined density range in step S714.

  Then, the pattern conversion unit 122 accesses the pattern data storage area 132 in the HDD 112, and from among the monochrome pattern data 140, 142, 144, 146, 148, 150, 152, 154 stored therein, the peak specifying unit Monochrome pattern data corresponding to the number of hues notified from 128 is randomly selected (step S718).

  When the pattern selection is completed, the pattern conversion unit 122 converts each hue into the monochrome pattern data randomly selected in step S718 (step S720).

  Thereafter, the control unit 102 outputs a print command to the print unit 108. In accordance with this command, the printing unit 108 prints a color image as a monochrome image (step S722). As a result, the color image is replaced with the selected monochrome pattern data and printed out.

<Operation>
When the color image data is acquired, the control unit 102 identifies a character area and a photograph area from the acquired color image data. The control unit 102 converts the areas (graph areas) other than the identified character area and photo area into different monochrome patterns for each hue. At this time, if there are different hues within a predetermined range of density, the control unit 102 converts them into different monochrome patterns.

<Action and effect>
According to this embodiment, in addition to the same operations and effects as (1) to (3) of the first embodiment, the following operations and effects are achieved.

  If there are different hues in a predetermined range of density, they are converted into different monochrome patterns, so that pattern conversion is performed only in areas where the density is close and the hue is different. Therefore, even when the density is close, the monochrome print output image can be easily distinguished.

  The present invention is not limited to the above embodiment.

  For example, in the above-described embodiment, an example is described in which, in the monochrome conversion process when color image data is read by the document reading unit 104, the character area and the photograph area are converted into a monochrome pattern and then the graph area is converted into a monochrome pattern. did. However, the present invention is not limited to such a configuration. In the monochrome conversion process when color image data is read by the document reading unit 104, the graph area may be converted into a monochrome pattern while the character area and the photograph area are being converted into monochrome. In this case, the image processing speed is increased.

  In the above embodiment, when the color image data is PDL data sent from the PC 118, the area other than the graph (character area and photo area) is developed as monochrome data, and then the graph area is converted into a monochrome pattern. An example of conversion was described. However, the present invention is not limited to such a configuration. When the color image data is PDL data sent from the PC 118, the graph area may be converted into a monochrome pattern while the area other than the graph (character area and photo area) is expanded as monochrome data. . Also in this case, the image processing speed is increased.

  Furthermore, regarding the scale data 192 shown in FIG. 10, if the scale interval is made finer than the state shown in the figure, the conversion to the monochrome pattern can be performed finely.

  It goes without saying that various design changes and modifications can be made within the scope of the claims attached to this specification.

  That is, the embodiment disclosed in this specification is merely an example, and the present specification is not limited to the embodiment described above. The scope of the present invention is indicated by the appended claims after taking into account the description of the present specification, and includes all modifications within the meaning and scope equivalent to the words described therein.

DESCRIPTION OF SYMBOLS 100 Image processing apparatus 102 Control unit 104 Original reading part 108 Printing part 112 HDD
118 PC
120 Image identification unit 122 Pattern conversion unit 124 Monochrome conversion unit 126 Frequency distribution generation unit 128 Peak identification unit 130 Graph recognition unit 132 Pattern data storage area 140, 142, 144, 146, 148, 150, 152, 154 Monochrome pattern data 180 Scale Data storage area 192 Concentration scale data

Claims (6)

An acquisition means for acquiring color image data;
An identification unit for identifying a character region and a photo region from the color image data acquired by the acquisition unit;
Pattern conversion means for converting areas other than the character area and the photograph area identified by the identification means into different monochrome patterns for each hue area;
An image processing apparatus comprising: a printing unit configured to print the image data subjected to pattern conversion by the pattern conversion unit together with image data subjected to monochrome conversion in an area other than the pattern conversion. The image processing apparatus according to claim 1.
The color image data is data read by a document reading unit,
The image processing apparatus includes:
Generating means for generating a frequency distribution of hues by counting for each hue of a region other than the character region and the photo region;
A hue peak specifying means for specifying a hue with a high frequency based on the frequency distribution of the hue generated by the generating means;
The image processing apparatus, wherein the pattern converting means includes means for converting each of the hue regions specified by the hue peak specifying means into different monochrome patterns. The image processing apparatus according to claim 1.
The color image data is print data sent from an external device for printing,
The image processing apparatus includes:
A graph recognizing unit for identifying a color region included in the graph by analyzing the print data;
The image processing apparatus, wherein the pattern conversion means includes means for converting each color region identified by the graph recognition means into a different monochrome pattern. The image processing apparatus according to any one of claims 1 to 3,
The pattern conversion means includes an means for converting into different monochrome patterns when there are different hues in a predetermined range of density. An acquisition step for acquiring color image data;
An identification step for identifying a character region and a photo region from the color image data acquired in the acquisition step;
A pattern conversion step for converting areas other than the character area and the photograph area identified in the identification step into different monochrome patterns for each hue area;
A printing step for printing the image data subjected to pattern conversion in the pattern conversion step together with image data subjected to monochrome conversion in a region other than the pattern conversion. On the computer,
An acquisition step for acquiring color image data;
An identification step for identifying a character region and a photo region from the color image data acquired in the acquisition step;
A pattern conversion step for converting areas other than the character area and the photograph area identified in the identification step into different monochrome patterns for each hue area;
An image processing program for executing a printing step for printing the image data subjected to pattern conversion in the pattern conversion step together with image data subjected to monochrome conversion in an area other than the pattern conversion.

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