JP2007060049A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of efficiently reducing an image data amount of even an original wherein a color signal/a monochrome signal changes on a midway of a line. <P>SOLUTION: Image data in each color by one page acquired by CCDs 21R, 21G, 21B are subjected to various processes such as A/D conversion, shading correction, and gamma correction and thereafter the resulting data are stored in a RAM 4. The image data by one page are demarcated into a plurality of regions, in each of which color/monochrome is discriminated. As to the regions discriminated to be color regions, the image data of each color component are read from the RAM 4 and outputted to an image memory 5, and as to the regions discriminated to be monochrome regions, monochrome image data are produced from the image data of each color component and the produced monochrome image data are outputted to the image memory 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image reading apparatus such as a color copying machine that reads an original by dividing it into a plurality of color components, and more particularly to an image reading apparatus that outputs image data by dividing the original into a color area and a monochrome area.

  In a color copying machine, either color processing or monochrome processing is executed in accordance with a user input designating color reading or monochrome reading. When reading an original in color, the amount of image data for one page is larger than when reading in monochrome. There are many originals that are partially color images, but the rest are monochrome images.

In such an original, instead of reading all the images in color, it is more efficient to read the monochrome image portion in monochrome because the amount of image data for one page is reduced. Therefore, a technique for determining whether each line is a color image or a monochrome image has been proposed (see Patent Document 1).
JP-A-11-27542

  However, there are many actual originals in which a color portion and a monochrome portion are mixed in one line. In the technique of Patent Document 1, whether such a document is a color image line or a monochrome image line is uniquely determined, and the amount of image data cannot be reduced efficiently. There's a problem.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an image reading apparatus capable of efficiently reducing the amount of image data even for a document whose color / monochrome changes in the middle of a line. To do.

  In an image reading apparatus according to the present invention, an image reading apparatus that reads an original by dividing it into a plurality of color components, storage means for storing the read image data of each color component, and image data stored in the storage means in a grid pattern A determination means for determining whether each divided area is color or monochrome, and for the area determined to be color by the determination means, the image data of each color component is output from the storage means and determined as monochrome. An output control means for generating and outputting monochrome image data is provided for the region thus formed.

  In the image reading apparatus of the present invention, a document is read while being divided into a plurality of color components, the read image data of the plurality of color components is divided into grid-like areas, and whether each divided area is color or monochrome is determined. Then, the acquired image data of each color component is output for the area determined to be color, and the monochrome image data is generated and output for the area determined to be monochrome. Therefore, it is possible to prevent the amount of image data from increasing more than necessary even for a document whose color / monochrome changes in the middle of a line.

  The image reading apparatus according to the present invention is characterized in that, in the above configuration, the output control means generates monochrome image data from image data of at least one color component.

  In the image reading apparatus of the present invention, monochrome image data is generated using image data of at least one color component. Therefore, monochrome image data is easily generated.

  An image reading apparatus according to the present invention includes a first storage unit that stores a read monochrome image data and a read image data of each color component in an image reading apparatus that reads a document in monochrome and reads it into a plurality of color components. A second storage means for storing the image data, a determination means for dividing the image data stored in the second storage means into a grid area, and determining whether each of the divided areas is color or monochrome, and a color by the determination means And output control means for outputting image data of each color component from the second storage means for the area determined to be monochrome, and outputting monochrome image data from the first storage means for the area determined to be monochrome. It is characterized by.

  In the image reading apparatus of the present invention, the original is read in monochrome and divided into a plurality of color components, and the read image data of the plurality of color components is divided into grid-like areas. It is determined whether the image is monochrome, and for each region determined to be color, the acquired image data of each color component is output, and for the region determined to be monochrome, the acquired monochrome image data is output. Therefore, it is possible to prevent the amount of image data from increasing more than necessary even for a document whose color / monochrome changes in the middle of a line.

  In the present invention, the document is divided into grid-like areas, and each divided area is determined whether it is color or monochrome. For each area determined to be color, the obtained image data of each color component is output, and the area determined to be monochrome. Since monochrome image data is generated and output, it is possible to efficiently reduce the amount of image data even for a document whose color / monochrome changes in the middle of a line.

  In the present invention, since monochrome image data is generated from image data of at least one color component, monochrome image data can be easily generated.

  Further, in the present invention, the original is divided into grid-like areas, and each divided area is determined whether it is color or monochrome, and for each area determined to be color, the obtained image data of each color component is output, and the area determined as monochrome Since the obtained monochrome image data is output, the amount of image data can be efficiently reduced even for a document whose color / monochrome changes in the middle of a line.

  Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. In addition, this invention is not limited to the following embodiment.

(First embodiment)
FIG. 1 is a block diagram showing a configuration example of an image reading apparatus according to a first embodiment of the present invention (Claims 1 and 2). The image reading apparatus includes a microprocessor unit (MPU) 1, a reading unit 2, a ROM 3, a RAM 4, an image memory 5, an operation unit 6, an external interface 7, and the like.

  The MPU 1 is connected to the above-described hardware units of the image reading apparatus via a bus, controls them, and executes various software functions according to a control program stored in the ROM 3.

  The reading unit 2 includes an image sensor 21 having CCDs 21R, 21G, and 21B that acquire analog color signals of R component, G component, and B component by reading an image, a multiplexer 22 that selectively switches analog color signals of each color, and analog color An AFE (Analog Front End) 23 that performs various processing such as offset processing and amplification processing on the signal, an A / D converter 24 that converts an analog color signal into a digital color signal, shading correction (sensitivity of the CCD) A shading correction circuit 25 that performs light amount distortion correction due to uniformity), a gamma correction circuit 26 that performs gamma correction (correction for adjusting the luminance of the image signal read by the CCD according to human visual characteristics), Line deviation correction memory that corrects line deviation of image signals of each color component 27, and a reading mechanism control circuit 28 that controls turning on / off of the light source 29 and rotation control of a motor 30 that drives scanning of the reading optical system.

  The ROM 3 stores various software control programs necessary for the operation of the image reading apparatus. The RAM 4 stores temporary data generated when the software is executed. The RAM 4 temporarily stores image data of each color component obtained by the document reading process by the reading unit 2. The image memory 5 is composed of a DRAM or the like, and stores final image data of each color component and monochrome image data. The operation unit 6 receives an external input from the user. The external interface 7 outputs the image data stored in the image memory 5 to an external device such as a recording device.

  In such a configuration, the RAM 4 functions as a storage unit that stores the read image data of each color component. The MPU 1 functions as a determination unit that divides the image data into grid-like areas and determines whether each of the divided areas is color or monochrome, and stores image data of each color component for the area determined to be color. It outputs to the image memory 5 from the means (RAM 4) and functions as an output control means for generating monochrome image data and outputting it to the image memory 5 for the area determined to be monochrome.

  Next, the operation will be described. A document is read by a reading optical system including a light source 29, an image sensor 21, and the like, and image data of each color for one page acquired by the image sensor 21 (R component image data, G component image data, B component image data). The image data) is stored in the RAM 4 after various processes such as A / D conversion, shading correction, and gamma correction are performed.

  The image data for one page is divided into a plurality of areas. FIG. 2 is a schematic diagram showing an example of the plurality of regions. In the example shown in FIG. 2A, one page is divided into 12 areas. The MPU 1 determines whether each area is color or monochrome based on the image data of each color. Specifically, a gradation histogram for each color component of all pixels is calculated for each region, and there is a bias greater than or equal to the first predetermined value among the numbers of gradations of the R component, G component, and B component in the gradation histogram. The area is discriminated as a color area (area hatched at a dense pitch in FIG. 2A), and an area that has only a deviation below the second predetermined value is a monochrome area (area not hatched in FIG. 2A). A region that is discriminated and has a deviation between the first predetermined value and the second predetermined value is determined as an indistinguishable region (a region hatched with a sparse pitch in FIG. 2A).

  Then, for an area that cannot be determined whether it is color or monochrome, the area is divided into smaller areas, and a color area or a monochrome area is determined for each divided small area based on the same determination criterion. . Finally, as shown in FIG. 2B, image data for one page is divided into a color area and a monochrome area.

For the area determined to be color, image data of each color component (R component, G component, B component) in the area is read from the RAM 4 and output to the image memory 5. On the other hand, for the region determined to be monochrome, monochrome image data (luminance data Y) is calculated from the R component, G component, and B component image data in the region based on the conversion formula (1) below. The monochrome image data is output to the image memory 5.
Y = 0.299R + 0.587G + 0.114B (1)

  In the conversion equation (1), since the coefficient of the G component is the largest, the G component image data may be used as it is as monochrome image data. In such a case, it is not necessary to obtain monochrome image data based on the conversion formula (1), and monochrome image data can be easily generated. In addition, the transfer time of image data can be reduced to 1/3 compared to color.

  As described above, in the first embodiment, image data for one page is divided into a plurality of areas, and it is determined whether each area is color or monochrome, and each color component (R component, G component, B component) image data is output, and monochrome image data is generated and output for a monochrome region. Therefore, even for a document whose color / monochrome changes in the middle of a line, the amount of image data can be efficiently reduced. It becomes possible to reduce.

(Second Embodiment)
FIG. 3 is a block diagram showing a configuration example of an image reading apparatus according to the second embodiment of the present invention (Claim 3). In FIG. 3, the same or similar parts as those in FIG.

The image sensor 21 of the reading unit 2 includes a CCD 21M that acquires analog monochrome signals in addition to the CCDs 21R, 21G, and 21B that acquire analog color signals of R, G, and B components. In the embodiment, the original is read in monochrome and is divided into a plurality of color components. In addition to the AFE 23M, the A / D converter 24M, the shading correction circuit 25M, and the gamma correction circuit 26M that perform the same functions as those in FIG. 1, the output system of the CCD 21M includes edge enhancement for enhancing the edge of the image. A circuit 31 is provided.

  In the configuration shown in FIG. 3, the RAM 4 functions as a first storage unit that stores the read monochrome image data and a second storage unit that stores the read image data of each color component. The MPU 1 functions as a determination unit that divides the image data into grid-like areas and determines whether each divided area is color or monochrome, and for each area determined to be color, the image data of each color component is added. 2 is output from the storage means (RAM 4) to the image memory 5 and functions as output control means for outputting monochrome image data from the first storage means (RAM 4) to the image memory 5 for the area determined to be monochrome.

  Next, the operation will be described. An original is read by a reading optical system including a light source 29, an image sensor 21, and the like, and image data of each color (R component image data, G component) for one page acquired by the image sensor 21 (CCD 21R, 21G, 21B). Image data and B component image data) are subjected to various processes such as A / D conversion, shading correction, and gamma correction, and are then stored in the RAM 4 and acquired by the image sensor 21 (CCD 21M). Monochrome image data for one page is stored in the RAM 4 after being subjected to various processes such as A / D conversion, shading correction, gamma correction, and edge enhancement.

  As in the first embodiment, the image data for one page is divided into a plurality of areas, and the MPU 1 determines whether each area is color or monochrome. Since the discrimination method in this case is the same as that in the first embodiment, the description thereof is omitted.

  For the area determined to be color, image data of each color component (R component, G component, B component) in the area is read from the RAM 4 and output to the image memory 5. On the other hand, for the area determined to be monochrome, monochrome image data in that area is read from the RAM 4 and output to the image memory 5. Therefore, at the time of monochrome, the transfer time of image data can be reduced to 1/3 compared to the case of color.

  As described above, in the second embodiment, image data for one page is divided into a plurality of areas, and it is determined whether each area is color or monochrome, and each color component (R component, G component, B component) image data is output, and monochrome image data is output for a monochrome region. Therefore, the amount of image data can be efficiently reduced even for a document whose color / monochrome changes in the middle of a line. Is possible.

  In addition, since the processing system for the monochrome image signal is provided independently of the processing system for the color image signal, high-quality processing can be performed as compared with the first embodiment. Further, since the edge enhancement circuit 31 is provided specifically for the processing system for monochrome image signals, it is possible to obtain image data with sharp edges. In this case, in the processing system for the monochrome image signal, the amount of image data to be processed is 1/3 as compared with the processing system for the color image signal. Therefore, even if the edge enhancement circuit 31 is provided, a processing delay occurs. There is nothing.

1 is a block diagram illustrating a configuration example of an image reading apparatus according to a first embodiment of the present invention (claims 1 and 2); It is a schematic diagram which shows an example of the some area | region which divided | segmented the image data for 1 page. It is a block diagram which shows the example of a structure of the image reader of 2nd Embodiment which concerns on this invention (Claim 3).

Explanation of symbols

1 MPU
2 Reading unit 3 ROM
4 RAM
5 Image memory 21 Image sensor 21R, 21G, 21B, 21M CCD

Claims (3)

  In an image reading apparatus that reads an original by dividing it into a plurality of color components, storage means for storing the read image data of each color component, and the image data stored in the storage means are divided into grid-like regions, A determination means for determining whether the area is color or monochrome, and for each area determined to be color by the determination means, image data of each color component is output from the storage means, and for an area determined to be monochrome, monochrome image data And an output control means for generating and outputting the image.   The image reading apparatus according to claim 1, wherein the output control unit generates monochrome image data from image data of at least one color component.   In an image reading apparatus that reads an original in monochrome and reads it into a plurality of color components, first storage means for storing the read monochrome image data, second storage means for storing the read image data of each color component, The image data stored in the second storage means is divided into grid-like areas, a discrimination means for discriminating whether each of the divided areas is color or monochrome, and each color component for the area discriminated as a color by the discrimination means And an output control means for outputting monochrome image data from the first storage means for an area determined to be monochrome.

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