JP2014096650A - Image processing device and method for controlling image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunction peripheral that performs ground color removal processing using ground color density calculated for each document irrespective of the number of documents or the number of copies.SOLUTION: A multifunction peripheral 10 that reads a document to generate first image data of the document, performs image processing on the first image data to generate second image data, performs color conversion on the second image data on the basis of a color conversion table, and prints it, comprises: a ground color density calculating unit 38 that calculates ground color density of the document from the first image data; and a storage unit 50 that stores the second image data and the ground color density in an associated manner.

Description

  The present invention relates to an image processing apparatus and a control method for the image processing apparatus.

  Multi-function machines that realize a scanner function, a printer function, and a copy function with a single unit are in widespread use. In such a multi-function machine, as shown in Patent Document 1 below, one color is obtained by calculating the background color density of an original and performing color conversion processing by a printing apparatus using a color conversion table based on the background color density. There is known a ground color removal processing function for converting a light color of a document to white by conversion processing and generating a copy image from which the background color (ground color) or show-through color of the document is removed.

Japanese Patent Laid-Open No. 1-213073

  However, when the background color removal is performed using the color conversion process of the printing apparatus, an image that is not ground-color-removed is stored by copying a plurality of pages of a document over a plurality of copies. Further, since the background color density of the document of each page is not retained, the first copy of each document is removed using the color conversion table based on the calculated background color density. Subsequent copies do not hold the background color density for each page, and are therefore color-converted using a prescribed color conversion table, so that appropriate background color removal according to the original on each page cannot be performed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The image processing apparatus according to this application example reads a document to generate first image data of the document, performs image processing on the first image data to generate second image data, and generates the second image data. An image processing apparatus for color-converting and printing data based on a color conversion table, wherein a ground color density calculating unit that calculates a ground color density of the document from the first image data, the second image data, and the ground image And a storage unit for storing the color density in association with each other.

  According to such a configuration, the background color density for each document calculated by the background color density calculation unit is stored in the storage unit in association with the document. Therefore, by using the stored background color density, Appropriate color conversion can be performed accordingly.

[Application Example 2]
In the image processing apparatus according to the application example, it is preferable that the ground color density calculation unit calculates the ground color density by statistically processing a density distribution of the first image data.

  According to such a configuration, the ground color density can be calculated with high accuracy by statistically processing the density distribution of the first image data.

[Application Example 3]
The image processing apparatus according to the application example includes a color conversion table generation unit that generates the color conversion table based on the background color density, and the color conversion table generation unit prints a plurality of copies of the document. In this case, when printing the first number of copies, the color conversion table is generated based on the background color density calculated by the background color density calculation unit, and when the second and subsequent copies are printed, stored in the storage unit. It is preferable to generate the color conversion table based on the ground color density.

  According to such a configuration, when the second and subsequent copies are printed, the color conversion table is generated based on the ground color density stored in the storage unit, so that the color is converted with the same color conversion table as the first copy. Can be converted.

[Application Example 4]
The image processing apparatus according to the application example may include a layout processing unit that performs layout processing on the second image data subjected to the image processing.

[Application Example 5]
In the image processing apparatus according to the application example described above, it is preferable that the image processing apparatus further includes a layout processing unit that performs a layout process on the third image data obtained by color-converting the second image data based on a color conversion table.

  According to such a configuration, since the color conversion of each document image is performed before the layout processing is performed, a plurality of images subjected to the ground color processing for each document can be assigned to one surface.

[Application Example 6]
The image processing apparatus according to this application example reads a document to generate first image data of the document, performs image processing on the first image data to generate second image data, and generates the second image data. An image processing apparatus for color-converting and printing data based on a color conversion table, wherein a ground color density calculating unit that calculates a ground color density of the document from the first image data, and the ground color density based on the ground color density A color conversion table generation unit that generates a color conversion table; and a storage unit that stores the second image data and the color conversion table in association with each other.

  According to such a configuration, the background color density for each document calculated by the background color density calculation unit is stored in the storage unit in association with the document. Therefore, by using the stored background color density, Appropriate color conversion can be performed accordingly.

[Application Example 7]
The control method of the image processing apparatus according to this application example reads a document to generate first image data of the document, performs image processing on the first image data to generate second image data, and A method for controlling an image processing apparatus for performing color conversion on a second image data based on a color conversion table, and printing a background color density of the document from the first image data; A storage step of storing the two image data and the background color density in association with each other.

  According to such a method, the background color density for each document calculated by the background color density calculation unit is stored in the storage unit in association with the document, so that the stored background color density is used to store the document. Appropriate color conversion can be performed accordingly.

1 is a block diagram showing a functional configuration of a multifunction machine according to an embodiment of the present invention. The figure explaining ground color removal. 6 is a flowchart for explaining copy processing.

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

(Embodiment)
FIG. 1 is a block diagram illustrating a functional configuration of a multifunction machine 10 as an image processing apparatus. The multifunction machine 10 includes an image reading unit 20, a control unit 30, a storage unit 50, and a printing unit 60. The control unit 30 includes an image processing unit 32, a layout processing unit 34, a histogram processing unit 36, a ground color density calculation unit 38, and a color conversion table generation unit 40. The printing unit 60 includes a color conversion unit 65.
In the multifunction machine 10, the image reading unit 20 reads a document, the control unit 30 performs a predetermined process on the read document image, and the printing unit 60 prints the image subjected to the predetermined process on a medium. It has a copy function to output. The predetermined process includes a background removal (background color removal) process for removing the background color of the document, and whether or not the background color removal is executed is determined by a user through a predetermined user interface (not shown). Via the MFP 10.

In the present embodiment, it is assumed that the image reading unit 20 includes an automatic document feeder (ADF) and is capable of continuously reading a plurality of documents. The control unit 30 and the storage unit 50 are assumed to be a computer device (not shown) that includes an external storage device such as a hard disk drive and is driven by a predetermined OS. The printing unit 60 is assumed to be an electrophotographic printing apparatus such as a color laser printer. The image reading unit 20, the storage unit 50, the printing unit 60, and the control unit 30 are connected so as to be communicable according to a predetermined communication standard by wire or wireless.
Note that these functional units are not limited to the described modes. For example, the printing unit 60 may be an ink jet printer. Further, the image reading unit 20, the control unit 30, the storage unit 50, and the printing unit 60 may be integrated as the multifunction device 10.

Note that the control unit 30 has functions of each functional unit described later by cooperation of hardware (for example, CPU, RAM, ROM, etc.) of the computer device and software stored in the ROM, the storage unit 50, or the like. Is realized.
The image processing unit 32 acquires RGB (Red, Green, Blue) data (first image data) of the image of the document read by the image reading unit 20, and performs image correction processing, edge processing, and the like on the first image data. The image processing is performed. In addition, the layout processing unit 34 performs layout processing such as rotation on the image of the first image data subjected to image processing, generates second image data composed of RGB data, and stores the second image data in the storage unit 50. .

The histogram processing unit 36 creates a histogram indicating the frequency distribution of the color density in the first image data. The ground color density calculation unit 38 statistically processes the density distribution of the histogram created by the histogram processing unit 36, thereby calculating a ground color density that serves as a reference value for removing the ground color from the document image. The calculated ground color density is stored in the storage unit 50 in association with the second image data stored in the storage unit 50.
The color conversion table generation unit 40 generates a color conversion table for performing ground color removal based on the ground color density calculated by the ground color density calculation unit 38. The color conversion table is used when the color conversion unit 65 of the printing unit 60 performs color conversion on the second image data.

Here, background color removal will be described with reference to FIG. The upper graph in FIG. 2 is an example of a histogram created by the histogram processing unit 36, and shows a frequency distribution of color density in the first image data. This histogram shows the frequency at which the density of the background of the document near white is high. The background color density calculation unit 38 sets the density B within a predetermined range from the peak A as the background color density. The ground color density may be set for each RGB, and one value may be set as the luminance value.
The lower graph of FIG. 2 shows the characteristics of the color conversion table generated by the color conversion table generation unit 40 based on the density B, which is the background color density. When a density less than density B is input, this color conversion table outputs the input density so that the density has a linear relationship with the input density, and the whiteness is enhanced as the input density approaches density B. When a density of B or higher is input, it is created so as to output a density of “white”. As a result, the background of the original and the portion having a lighter density than the background are output in white.

In the present embodiment, when printing a plurality of copies of a document composed of a plurality of pages, the control unit 30 generates the second generated by the layout processing unit 34 when printing each first page of the first copy. After the image data and the ground color density calculated by the ground color density calculation unit 38 are stored in the storage unit 50 in association with each other, the creation of the color conversion table and the printing process are instructed. Then, when printing the second and subsequent copies, the control unit 30 does not acquire the image of the document by the image reading unit 20 and the second image data and the ground color of the first copy stored in the storage unit 50. The density is acquired for each page, a color conversion table is created using the acquired second image data and the ground color density, and a printing process is instructed to the printing unit 60.
The printing unit 60 acquires the second image data stored in the storage unit 50, performs color conversion on the second image data based on the color conversion table created by the color conversion table generation unit 40, and further performs predetermined color conversion. Based on a table (for example, a three-dimensional lookup table), third image data composed of CMYK (Cyan, Magenta, Yellow, Black) data is generated. An image based on the generated third image data is formed on a medium such as paper by a print engine (not shown) of the printing unit 60.
FIG. 3 is a flowchart for explaining processing of the copying function by the multifunction machine 10. This process is started when the user sets a plurality of documents on the ADF, selects the ground color removal process, and instructs a plurality of copies.

When this process is started, the CPU of the control unit 30 initializes the page counter (step S100), and determines whether or not the process is the first copy (step S102).
In this case, since the process is the first copy (Yes in step S102), the CPU of the control unit 30 instructs the image reading unit 20 to read the first document, and the first image data of the first document. Is acquired (step S104).
Next, the CPU of the control unit 30 calculates the ground color density of the first image data by histogram processing (step S106).
Next, the CPU of the control unit 30 performs image processing and layout processing on the first image data to generate second image data (step S108).

Next, the CPU of the control unit 30 associates the second image data with the ground color density and writes them in a predetermined area of the storage unit 50 (step S110).
Next, the CPU of the control unit 30 generates a color conversion table based on the background color density (step S114), and generates third image data obtained by color-converting the second image data based on the generated color conversion table. Accordingly, the printing unit 60 is instructed (step S116).
Next, the CPU of the control unit 30 instructs the printing unit 60 to print based on the third image data. As a result, a copy image of the first original is output from the printing unit 60 (step S118).

Next, the CPU of the control unit 30 determines whether all pages have been printed (step S120). In this case, since it is the first page (No in step S120), the page counter is incremented (step S122), and the process returns to step S102. As a result, the steps S102 to S120 are repeated for the next page of the document, and the second image data and the ground color density of each page are written in the storage unit 50 in association with each other.
If each of the steps S102 to S120 is executed for all pages (Yes in step S120), whether or not the CPU of the control unit 30 performs the next number of copies (second number) is printed. Is determined (step S124).

When printing the next number of copies (Yes in step S124), the CPU of the control unit 30 returns to step S100 to initialize the page counter, and is not the first copy in the determination in step S102 (No). Then, the second image data and the ground color density corresponding to the page are read from the predetermined area of the storage unit 50 (step S112).
Subsequently, the CPU of the control unit 30 repeats steps S114 to S120 until the copy images of all pages are printed.
Then, the CPU of the control unit 30 repeats the same processing as the second copy for the third and subsequent copies, and when the designated number of copies is completed (No in step S124), the series of processing ends.

According to the embodiment described above, the following effects can be obtained.
(1) When printing a plurality of copies of a document composed of a plurality of pages, the second image data and the background color density are stored when printing each page of the first first copy, and the second and subsequent copies are printed. When printing, the stored second image data and ground color density are read and printed. Therefore, even in the second and subsequent copies, the same ground color processing effect as that in the first copy can be enjoyed, and optimal ground color removal can be performed according to each page.
(2) Since the control unit 30 generates a color conversion table corresponding to the ground color process and performs the color conversion process in the color conversion unit 65 provided in the subsequent printing unit 60, the control unit 30 is newly provided with a color conversion unit. There is no need, and the multifunction machine 10 can be produced at low cost.

  As mentioned above, although preferred embodiment was described referring an accompanying drawing, suitable embodiment is not restricted to the said embodiment. The embodiment can of course be modified in various ways without departing from the scope, and can also be implemented as follows.

(Modification 1) In the above-described embodiment, the second image data and the ground color density are linked and stored in the storage unit 50. However, the color conversion table generated by the color conversion table generation unit 40 based on the ground color density is used. An aspect in which the second image data is associated with the second image data and stored in the storage unit 50 can be assumed. In such an aspect, the process of generating a color conversion table based on the ground color density in the second and subsequent copies becomes unnecessary, and the printing efficiency can be improved.
(Modification 2) In the embodiment, the layout process is executed before the color conversion process. However, it is also possible to assume a mode in which the layout process unit 34 is provided in the printing unit 60 and the layout process is executed after the color conversion process. . In such an aspect, the ground color removal processing can be applied even when performing layout printing in which a plurality of pages are allocated to one sheet.
Moreover, the apparatus which implements the above methods may be realized by a single apparatus or may be realized by combining a plurality of apparatuses, and includes various aspects.
Each configuration and the combination thereof in the above embodiment is an example, and the addition, omission, replacement, and other changes of the configuration can be made without departing from the spirit of the present invention. In addition, the present invention is not limited to the embodiments, and is limited only by the scope of the claims.

  DESCRIPTION OF SYMBOLS 10 ... MFP, 20 ... Image reading part, 30 ... Control part, 32 ... Image processing part, 34 ... Layout processing part, 36 ... Histogram processing part, 38 ... Ground color density calculation part, 40 ... Color conversion table generation part, 50: storage unit, 60: printing unit.

Claims (7)

A document is read to generate first image data of the document, image processing is performed on the first image data to generate second image data, and the second image data is color-converted based on a color conversion table. An image processing apparatus for printing
A ground color density calculating unit that calculates the ground color density of the document from the first image data;
An image processing apparatus comprising: a storage unit that stores the second image data and the background color density in association with each other. The image processing apparatus according to claim 1.
The ground color density calculation unit calculates the ground color density by statistically processing the density distribution of the first image data. The image processing apparatus according to claim 1,
A color conversion table generating unit that generates the color conversion table based on the background color density;
The color conversion table generation unit is configured to print the color conversion table based on the ground color density calculated by the ground color density calculation unit when printing the first copy when printing a plurality of copies of the plurality of documents. An image processing apparatus that generates the color conversion table based on the ground color density stored in the storage unit when generating and printing the second and subsequent copies. The image processing apparatus according to any one of claims 1 to 3,
An image processing apparatus comprising: a layout processing unit that performs a layout process on the second image data subjected to the image process. The image processing apparatus according to any one of claims 1 to 3,
An image processing apparatus comprising: a layout processing unit that performs layout processing on third image data obtained by color-converting the second image data based on a color conversion table. A document is read to generate first image data of the document, image processing is performed on the first image data to generate second image data, and the second image data is color-converted based on a color conversion table. An image processing apparatus for printing
A ground color density calculating unit that calculates the ground color density of the document from the first image data;
A color conversion table generating unit that generates the color conversion table based on the ground color density;
An image processing apparatus comprising: a storage unit that stores the second image data and the color conversion table in association with each other. A document is read to generate first image data of the document, image processing is performed on the first image data to generate second image data, and the second image data is color-converted based on a color conversion table. An image processing apparatus control method for printing
A background color density calculating step of calculating the background color density of the document from the first image data;
A storage step of storing the second image data and the ground color density in association with each other.

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