JP3144788B2 - Color document image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a function of inputting, storing, and retrieving a document, particularly a document containing color information such as a color photograph, as image data, and a function of outputting to a display or a printer. An image having the function of efficiently encoding an image in which a monochrome image and a color image are mixed, and encoding the image in a format compatible with a device that outputs only monochrome binary data such as a conventional facsimile. Related to a processing system.

[Conventional technology]

2. Description of the Related Art Conventionally, in a device that handles a color image as digital data, the image is separated into three primary colors of red, green, and blue, and three types of multivalued data that can be output (hereinafter, each component is referred to in the present specification. Are called R, G, and B, and the data of each color component is referred to as R data, G data, and B data).

For example, in a color copying machine, the input R, G,
Output multi-valued image data of B. Also, when binarization processing is necessary, such as outputting to a printer, multi-valued RGB data is binarized and output independently for each color. As a well-known example for achieving high functionality of this system, there is, for example, JP-A-64-51583. This known example shows a method in which a color image is separated into four colors of yellow, magenta, cyan, and black, and each color is binarized and stored. However, when the image information is separated into four colors of yellow, magenta, cyan, and black, if only the information of the black is output, the image of the colored portion is lost. No consideration is given to displaying intermediate colors such as color photographs.

On the other hand, in a TV or a VTR, a method of converting RGB color image data into luminance information and two kinds of color difference information, performing an orthogonal transform, encoding the coefficients, and storing the same is widely used. ing. This method handles only luminance information in a monochrome area having no color difference information. Therefore, the coding efficiency is high for an image including many monochrome areas. Therefore, an example of using this method for a document is shown. (For example, Japanese Patent Application Laid-Open No. 63-9282) [Problems to be Solved by the Invention] Since the color tone and the saturation of a color image are greatly affected by the characteristics of the output device, it is difficult to output once accumulated data. Need to correct these. However, in order to perform the correction processing, it is necessary to handle an image as multi-value data. Therefore, the image described in the known example is changed to 2
The binarization and accumulation method cannot be applied to an image in which color tone reproduction is required.

Further, a generally used color document often has a large monochrome area while including a color image in a part of the image. In particular, in a monochrome document or the like with a red seal, the color information is significant only when it is colored, and it is not so important to accurately reproduce colors. It is inefficient to accumulate all R, G, B data for these images. Further, even in a document in which color photographs are mixed, a large number of monochrome character areas are often included in the area ratio. Therefore, a system for documents is required to have high encoding efficiency for monochrome images and characters, even for systems for color images. However, in the method of independently encoding R, G, and B, since redundancy is high and encoding efficiency is low,
An electronic file system that stores a large amount of document image data, or an FA that needs to send document images at a low data transfer rate
Not suitable for X etc. In particular, a method of handling RGB multi-valued data as it is is not suitable for the above-described device because the data amount becomes enormous. (Hereinafter, a monochrome portion of an image is referred to as a monochrome region.) On the other hand, a data encoding method using luminance / color difference conversion is as follows.
It was originally designed for devices that handle natural images such as TVs. Therefore, it is suitable for an image having a gradual change in density, but the following problem occurs when handling a document image including many portions having a very large change in density such as characters.

(A) Since the density change of a line graphic such as a character is sharp, the coding efficiency is significantly reduced.

(B) When the compression efficiency by encoding is increased, lossy encoding is performed. Therefore, when data transfer is performed using raster image data as a medium such as a facsimile, the data changes sequentially every time the data is converted, that is, each time the data is transferred.

(C) Documents that handle documents as binary images, such as faxes and electronic file systems, cannot be directly output.

(D) Data compatibility with the conventional monochrome system is lost.

Therefore, there has been no means for efficiently accumulating a color document in which a color photograph requiring gradation and a character requiring high resolution are mixed by a single encoding method.

A first object of the present invention is to provide a color image processing apparatus that efficiently encodes and accumulates various types of document images regardless of whether they are color documents or monochrome documents. Above all,
Efficient storage can be performed efficiently for images with a mixture of monochrome parts, which are common in color documents.Furthermore, for color documents where color reproduction is not important, such as documents with red seals, where color reproduction is not important An object of the present invention is to provide an efficient color image processing apparatus.

Another object of the present invention is to provide a color image processing apparatus compatible with a conventional image processing apparatus for monochrome images.

At the same time, a third object is to provide a color image processing method for storing color image data in a format that maintains compatibility with conventionally stored monochrome image data.

It is a fourth object of the present invention to provide a color image processing apparatus capable of changing the color tone and the color of an image even when a color image stored once is output.

Still another object of the present invention is to provide an image processing apparatus capable of displaying the content of each image at a high speed, for example, when searching for the content of color image data stored in a large amount on an optical disk or the like. Is to do.

Furthermore, many fax and electronic file systems that have been widely required so far have an input / output device for binary monochrome images. Therefore, color document imaging systems can also be used more widely if they are compatible with them. For this purpose, it is necessary to maintain compatibility in the data recording format, but this compatibility has not been considered in the past.

[Means for solving the problem]

In order to solve each of the above-mentioned problems, the present invention has means for handling color image data as a plurality of independent binary image data.

Specifically, when one color image is recorded, three binary images of the image in which the R component, the G component, and the B component are respectively recorded are referred to as R data, G data, and B data, respectively. It accumulates and combines the three binary images at the time of output,
It has a means to represent two color images.

Further, the image processing apparatus has means for storing only luminance data of the image as a single image and expressing a monochrome image. The luminance data can be replaced with, for example, G data. Hereinafter, in the present specification, data of three primary colors of a color image are called R data, G data, and B data, respectively, and three pieces of binary image data used to represent one image are referred to as three pieces of binary image data. When individually indicated, they are called planes. The luminance data is represented by Y.

First, in order to express only a specific color such as red or blue in an image such as a document with a red seal in color, the present invention provides a binary data Y indicating luminance information and a binary data Y indicating only a portion of the color. It has means for accumulating data as independent images. Specifically, there are means for storing a plane of luminance data for recording a black and white binary image, and means for storing binary image data indicating only pixels to be displayed in red, for example.
That is, image data is accumulated as two binary images.
Therefore, there is provided a means for extracting only pixels of the color from the image.

On the other hand, in order to express a full-color image such as a photograph, data of each plane of R, G, and B is recorded, and each plane is provided with means for displaying R, G, and B, respectively.

Therefore, in order to realize the first object, the present invention has an input storage unit in each of the above-mentioned formats, and further has a unit for switching each processing unit according to a target image.

The second object is to provide a means for binarizing each multi-value data as an independent image as described above and a means for accumulating the binary data in the same format as a conventional monochrome binary image. It can be achieved by having. That is, the data format of each plane is the same as that of the conventional monochrome binary image system.

The third object can be achieved by having means for displaying only the luminance plane in monochrome, and displaying the image data accumulated by the conventional monochrome system as a luminance plane.

On the other hand, the fourth purpose is to output 2
This can be achieved by having means for reproducing multi-valued image data from value image data and means for performing image processing on the reproduced multi-valued image data.

The fifth object can be realized by providing means for displaying only the above-mentioned luminance plane in monochrome when displaying an image.

In order to cope with the various types of images described above, the present invention has means for executing a plurality of processing modes as a data accumulation and binary processing method, and furthermore, according to a target document, these are executed. It has means for switching and means for recording an identifier for identifying the mode together with the image data to be stored. Further, the reading section of the stored data has means for reading the recorded identifier, and the image display section has means for switching the color to be displayed on each plane according to the identifier.

[Action]

First, a description will be given of data accumulation and binary processing mode executed by the present invention in order to cope with the various images described above.

According to the present invention, data predetermined for each mode is stored and a binary processing method is executed, and an identifier of this mode is also recorded in the image storage character. This mode identifier is referred to in image display, and is used for designating data necessary for display and determining an appropriate combination method.

 The contents of each mode are as follows.

Mode (I) Monochrome mode: of the image data, only the luminance data Y is stored.

Mode (II) Multi-color mode: luminance data Y and pixel data R to be displayed in red are extracted from the input color image data, and the respective image data are accumulated in separate planes. For example, a binary image obtained by binarizing luminance data and a binary image of a binary image in which only pixels desired to be expressed in red among pixels recorded as black in the binary image are described. Store the image.

At the time of display, the image of the R plane is expressed in red, and the other pixels are displayed in black and white according to the Y plane.

Mode (III) Full color mode: R, G, B color image data is stored in R, G, B planes, respectively. At the time of display, each plane is combined with R, G, and B and displayed.

Mode (IV) Mixed mode: a color area that requires color information from an image and a monochrome area are identified, and for the monochrome area, the luminance signal Y is stored in the G plane, and the R and B planes are left blank. . On the other hand, in the color area,
R, G, and B binary data are accumulated in each plane. An area identifier indicating a color area and a monochrome area
Fcm is stored as a fourth plane.

Here, the mode (I) is used when a monochrome document is input. As described above, the mode (II) is a mode for red and blue monochromatic documents, which are abundant in office documents and the like, and which have been stamped and corrected. However, this mode can be applied even when there are two or more colors to be expressed. The mode (III) is a mode used for a color photograph or the like. Further, the mode (IV) is a mode for a document in which a monochrome document and a color photograph are mixed.

Next, the operation of each unit in the above-described problem solving means will be described.

First, when dealing with a monochrome image, the encoding efficiency is reduced only when color information is required in the image, that is, only in mode (III), where all the R, G, B color information is This can be solved by accumulating and storing only luminance information in the case of a monochrome part in an image or a document specified as a monochrome image from the beginning.

In the present specification, as an example, in the modes (I) and (II), the luminance data Y is recorded as “1” for a pixel displayed in black and “0” for a blank portion.

In the case of the mode (I), since the stored data is only the luminance information, the above-described problem does not occur.

On the other hand, when accurate color reproduction is not required, such as a document with a red seal, the data amount of the monochrome portion can be made the same as that of the mode (I) by the processing of the mode (II).

In red-marked documents, red-paper correction documents, and the like, it is important information that red is "colored", and accurate reproduction of colors such as color photographs is generally not required. Therefore, these images are handled in the form of monochrome image data, plus, image data specifying a colored portion. Specifically, first, the luminance data Y is recorded as a single plane. Here, not only black pixels are described in the luminance plane, but also pixels that should be displayed in red or another color are described. Then, when displayed in monochrome, a pixel expressed in black, that is, Y = “1”
Among the pixels of the above, pixels to be displayed in “red” such as red characters are extracted and recorded as “1” in the R plane. Here, in the R plane, binary image data in which only pixels written in “red” are represented by “1” and others are represented by “0” is recorded. Then, since the R plane is all "0" in the area described in black and white, the encoding efficiency is high, and the data amount is almost the same as that of the case of only monochrome binary image data, including the color information, and is recorded. it can.

At the time of output, of the luminance data Y, pixels whose R plane content is "0" are displayed in black, and pixels whose R plane content is "1" are displayed in red. As described above, the luminance plane includes the pixels to be displayed in red, so if only the luminance plane is displayed in monochrome, the color document will be displayed in the same way as when inputting with a conventional monochrome system can do.

On the other hand, in the mode (IV) that targets a document in which a full-color image such as a photo and a monochrome image are mixed,
By accumulating the monochrome identification information Fcm, the redundancy of the data of the monochrome portion can be suppressed. This mode is particularly effective when a large amount of documents are continuously input using an automatic paper feeder or the like. On some pages of the document to be entered,
When a color photograph is included, in mode (III), all pages of the document are recorded with three pieces of RGB data, and the amount of data to be stored is three times as large as that in monochrome storage. On the other hand, in mode (IV), on most pages,
Since only the luminance data Y is accumulated, and the R and B planes and the attribute identifier Fcm indicate blanks on almost all pages, efficient encoding can be realized.

Hereinafter, in the present specification, the attribute identifier Fcm outputs “0” when the target area is a monochrome image, and outputs “1” when the target area is determined to be a color area. Think.

In this case, in the color area, R, G, B
It is necessary to record the above-described data, record the above-described luminance and red and blue data in the monochrome area, and have a means for switching the data display method according to the attribute information when outputting an image.

In this method, since image data is binarized and stored, the MH (Motion) is used in the same manner as in a conventional apparatus for monochrome binary images.
dified Huffman) and MR (Modified Read). Therefore, for example, a recording medium such as an optical disk can maintain compatibility with a conventional monochrome system.
Therefore, as described above, the luminance data Y can be output by a conventional monochrome system.

In addition, in these binary image coding methods, there is no problem when the coding efficiency is sharply reduced in a line figure such as a character.

Furthermore, in these binary image data encoding methods,
The data amount of a portion where 0s or 1s continue can be minimized.
Accordingly, information such as color / monochrome identification information in which a value change is in units of regions has extremely high coding efficiency. Also,
The R plane stored in the mode (II) is also blank except for the color portion, so that high coding efficiency can be obtained. In this example, the case where only red is displayed as the color information to be added to black and white is described.
By increasing the number of planes to be stored, it can be executed by the same means.

Next, a case where a full-color image is stored will be described. When a full-color image is represented by binary information, it is necessary to perform pseudo halftone processing in order to reproduce not only density but also color. However, when the pseudo halftone processing is applied to a line figure such as a character, the resolution of an image is reduced. Therefore, the adaptive type 2 is used for a portion that does not require color reproduction, such as a monochrome portion of a mixed document and a multi-color document.
The line figure is more finely recorded by the value processing. On the other hand, in the color area, pseudo halftone processing is performed even for a line figure in order to reproduce a color.

Further, when an image is displayed by superimposing three binary image data of R, G, and B, a color that does not originally exist may appear due to a difference in values between the three data. This is hereinafter referred to as color noise.

In the present invention, the color noise is divided into the modes (III) and (IV).
Occurs in the case of To prevent this color noise, 3
The plane data must have equal values.

Therefore, according to the present invention, in the mode (III), the color / monochrome determination section determines the monochrome area,
Further, this problem is solved by having means for recording the same value on the three planes of R, G, and B for pixels determined as a character area by the character / photograph area determination unit.

In order to realize each of the above operations, it is necessary to provide a means for executing a binarization method of data and selecting data to be stored based on a predetermined condition using a mode and an output of each area identification device.

On the other hand, when a color image is output, image processing such as affine transformation, change of a specific color, or adjustment of color tone requires that the image data be multi-valued at the time of processing. Therefore, these functions can be realized by reproducing multi-value data from an image stored as binary data.

Further, for example, in the case of searching, when displaying the contents of a color image composed of data of 2, 3 or 4 planes at a high speed, for example, only the luminance plane of the image data stored on an optical disk or the like is used. Is read and displayed in monochrome, a monochrome image can be displayed at high speed simply by reading data for one plane.

〔Example〕

 One embodiment of the present invention will be described in detail with reference to the drawings.

First, a data recording format of a multi-color image, which is one of the features of the present invention, will be described with reference to FIG. This corresponds to the mode (II) described above.

FIG. 1A shows a document in which black and red characters are written. In the figure, the characters in 11 are black, and the characters in 12 are red. When this document is input in the above-mentioned mode (II), for example, two pieces of binary image data stored on an optical disk or the like are images shown in (b) and (c) in FIG. (B) is a plane for recording the luminance data Y. The image is recorded as binary data, and both the characters described in black and red in the original image are described as a single-color binary image. The mode in which only the luminance data Y is recorded corresponds to the mode (I) described above. In this specification, as described above, in the case of the mode (I), a pixel in which a character is described is “1”, and a pixel in a blank portion is “0”.

On the other hand, (c) shows two types of image data described in the R plane. Of the pixels described as "1" in the luminance data, "1" is described only for pixels determined to be red. The structure of the part for extracting and binarizing this red will be described later.

As a result, the luminance data Y (x, y) shown in FIG.
The following relationship holds between R (x, y) shown in (c).

if R (x, y) = 1 then Y (x, y) = 1, so that the R plane is “1” and the Y plane is “0”
Does not occur when

FIG. 2 is an example of a data format for expressing each color in a document in mode (II). In the figure, Y is luminance data, R
Indicates the contents of the R data. The color to express is white,
In the case of black and red, data can take three values as shown in the figure.

On the other hand, when displaying a multi-color image from three binary images (b) and (c) stored on an optical disk or the like,
There are two types of cases, color output and monochrome output. FIG. 2 also shows the colors at the time of output. When the image of FIG. 1 is displayed in color, the image of (c) is displayed in red, and the parts other than red are displayed in black and white according to (b). Specific means for realizing this display method will be described later.

Also, when a plurality of stored images are continuously displayed, high-speed display is possible by reading out only the Y data and displaying the data in monochrome.

By using only this Y data, data compatibility can be maintained with a device that handles a monochrome binary image such as a fax. This feature is the same in other modes.

In this example, the color reproduced at the time of displaying an image is one color red, but the same applies to other colors. Also, a plurality of individual colors can be displayed as a specific color. In this case, for example, when n expressions are required, n + 1
The binary image data of the plane is stored.

As an example, FIG. 3 shows an example of expressing two colors of red and blue in addition to black and white. (A) in the figure is a document in which characters of three colors of black, red and blue are written. In the figure, the character in 16 is black, the character in 17 is red, and the character in 18 is blue. When this document is input in the mode (II) described above, the image is composed of three images shown in (b), (c), and (d) in FIG.
It is stored as value image data. (B) is luminance data Y
(C) is binary image data describing pixels to be displayed in red and (d) in blue. In this case,
FIG. 4 shows a data format for expressing each color in the document.

Next, the mode (III) for color photographs and the like will be described. FIG. 5 shows a data recording format in the mode (III). The data is recorded as R, G, B three pieces of binary data. In the figure, (a) 20 is an image in which color photographs are mixed, (b) is an R plane, (c) is a G plane,
(D) shows the contents of the binary image data of the B plane. In the figure, the characters in 21 are described in black, and the characters in 22 are described in a specific intermediate color. On the other hand, 23 indicates an area where a color photograph is described.

Here, in this mode, the colors recorded according to the data content of each plane are shown in FIG. Mode (II
In the case of I), white and black are also treated as one color.

Regarding binarization, when a full-color image such as a photograph shown as an area 21 in FIG. 5 is represented by binary data of R, G, and B, each of the R, G, and B data is subjected to pseudo halftone processing. And binarized. Therefore, 33, 43, in FIG.
Reference numeral 53 denotes data obtained by binarizing each of the R, G, and B data independently by pseudo halftone processing.

On the other hand, in this mode, for example, a monochrome halftone area such as 21 is not subjected to pseudo halftone processing during binarization processing.
This is performed by switching between two types of binarization methods using means for separating a character area and a photograph area from a document image by a known method. Further, in order to correctly represent the area where black characters are described, R,
Make the value equal between G and B planes. Specifically, pixels in the character area and determined as the monochrome area are R,
This can be realized by writing the same value on the three planes G and B. Therefore, 31, 41, and 51 describe the same value.

However, even in the character area, if it is necessary to reproduce the color of a colored character such as 22, for example, pseudo halftone processing is required for expressing the color. Accordingly, this function is realized by having means for identifying a color area and a monochrome area in addition to the identification of a character area and a photograph area. In this case, independent values are described for 32, 42, and 52, respectively.

The various determination results and the conditions for selecting the binarization processing method according to the designated mode will be described later in detail.

Next, a mode (IV) for an image in which a color area and a monochrome area are mixed will be described.

This mode is particularly effective when a document or the like composed of many pages is stored as image data. In general,
When a document or the like composed of a large number of images is input, for example, a device for automatic input called a sorter is used.

In this case, the efficiency of the input operation can be improved by eliminating the need for the attendant of the operator. However, while typing,
If there is no operator, it is difficult to switch the mode for each image. Then, when a color region is included in some pages in the input document, it is necessary to input the entire image as a color image. Here all images are in mode (III)
, The monochrome image requires three times the data amount as compared with the case of inputting in the original monochrome mode.

On the other hand, the mode (IV) has, as the fourth plane, an identifier indicating whether each part in the image is a color area or a monochrome area. Since this identifier can be realized by a binary flag, it can be recorded in the same manner as each plane described above.

FIG. 7 shows an example of a recording format in the mode (IV). (A) in the figure is an example of the same color image as in FIG. 5 (a). (B), (c), and (d) are binary image data of R, G, and B, respectively, and Fcm is a binary identifier for identifying a color area and a monochrome area for each part of the image. here,
It is assumed that the identifier Fcm (x, y) is “1” when the pixel IM (x, y) is color, and “0” when the pixel IM (x, y) is monochrome. Then, in the binary data Fcm, 92 and 93 corresponding to the color regions 22 and 23 in the image (a) are “1”, and the other portions are “0”.

Here, in the portion where Fcm = 1, binary image data of R, G, and B is described in each of the R, G, and B planes. In this region, black is described as R = G = B = 0. On the other hand, for example, in the black character portion 21, the recording format is the same as the monochrome input, and the pixels described as black are R, G, B
Is described as "1" only in one plane. In this example, the G plane is the plane.

In the case of image display, in the present recording method, only the G plane is read as image data in the portion where Fcm = 0, and G = 1
If so, black is output, and if G = 0, white is output. On the other hand, Fcm = 1
The three planes of R, G, and B are read for the pixel of, and displayed in the same manner as in the mode (III). Therefore, the mode (I
The image output unit corresponding to V) needs to have means for switching the display color of the G plane according to the value of the identifier Fcm.

When image data is recorded by this method, for a monochrome image, Fcm = 0, R = 0, G = 0, and high coding efficiency can be obtained. Documents with mixed color images can be recorded by volume. On the other hand, even in an area where color and monochrome are mixed, the identifier Fcm switches between 0 and 1 in units of area, so that the coding efficiency is high and image data can be stored with a data amount almost equal to that in mode (III). .

Next, a method for realizing image storage in each of the above-described recording formats will be described. First, FIG. 8 shows an example of the entire configuration of the present invention.

In the figure, reference numeral 100 denotes a color scanner which optically reads an image of a document or the like by a known means and outputs it as multivalued digital data such as RGB, for example, and 150 denotes one of the above-described recording mode (I) to (IV) An input mode designating unit for designating image data, 200 is an image input unit for binarizing input multi-value data of each color of RGB for data storage, 310, 320, 330, 340 is a frame memory 400 for temporarily storing output results, and a binary binary memory A data conversion unit that converts the image data into a format suitable for input to a display device such as a high-definition color CRT.
An image display unit such as a high-definition CRT that inputs and displays multi-valued data of GB, 600 encodes binary data in the frame memory and records it in a large-capacity data storage unit such as an optical disk, or has already been stored A data storage unit 900 for reading and decoding data is a control unit for controlling the entire system.

Here, one of the characteristic suitable portions of the present invention is a data input section.
200. Therefore, the image input portion 200 will be described next. The part related to image input among the parts shown in FIG. 8 will be described with reference to FIG.

In the figure, reference numeral 100 denotes a color scanner for optically reading an image such as a document as described above, and reference numeral 150 denotes an input mode designation unit for designating a mode at the time of input. Also, 310,320,330,340
Is a frame memory for temporarily storing binary data of each plane.

A feature of the data input unit 200 is that data described in each plane is selected in addition to the binarization method based on a plurality of types of area determination results.

As means for determining an area with respect to an input image, a color / color identification unit 210 determines whether each pixel of the image belongs to a color area or a monochrome area based on three pieces of RGB multi-valued image data by means described later. A monochrome identification unit, 220 is a color identification unit that determines whether each pixel of the image belongs to a predetermined color such as red or blue, and 230 is a unit that inputs multi-valued digital image data by known means. And a character / photograph area determination unit that determines whether each pixel of the image belongs to a line graphic area such as a character or a halftone area such as a photograph. As means for independently binarizing RGB multi-valued image data, 240 is a binarization processing unit corresponding to an image such as a line figure by a known means, and 250 is a binarization processing by pseudo halftone processing Is a dither processing unit that performs the following. Meanwhile, 26
A selector 0 selects and outputs data to be stored from two types of binarization processing results for three RGB images based on the input mode and each determination result.

Here, in each mode, each frame memory 310, 32
At 0,330,340, the contents of the data to be recorded are shown in FIG.
Hereinafter, in this specification, the data expanded in the frame memory 310 is referred to as DATA-2, DATA-3, and DATA-4, respectively, the data stored in DATA-1, 320, 330, and 340.

In FIG. 10, "-" indicates that data is not recorded. The image data stored in the mode (I) is recorded in the frame memory 810 in Y only. Mode (II) stores data of two planes, and mode (III) stores data of three planes.
Furthermore, in mode (IV), 4 planes are 310,320,330,34
Store at 0.

Now, in order to briefly describe the features of the present invention, it is assumed that the color scanner 100 simultaneously outputs RGB multi-value data of each pixel on an image. The signal line 110 sends R data, 120 sends G data, and 130 sends B data. Further, in this example, the luminance data is substituted with the G data for simplification of the description, but it is also possible to calculate the luminance data by performing arithmetic processing on three types of RGB multi-valued data.

The color / monochrome discriminating unit 210 uses the known means or the like to convert the mode (III) from the input RGB multivalued data.
And (IV). The binary color / monochrome discriminating unit Fcm is output.

On the other hand, the purpose of the color identification section 220 is to extract pixels described in a specific color plane in the mode (II). In the present embodiment, a case where a red pixel is extracted will be described as an example. However, the number of colors to be extracted is one or more, and the color itself can be arbitrarily set. The identifier Frb output from the color identification unit 220 has a different format depending on the number of colors to be extracted, and is a 1-bit signal when extracting only red. The following relationship exists between the number Cnb of colors to be extracted here and the number N of bits of the identifier Frb.

N ≧ log ₂ (Cnb + 1) As a method of extracting a specific color, a number of methods using a bias of values between RGB and the like have already been known.

On the other hand, the character / photo region determination unit 230 aims to identify, as a binarization method, a region where a line graphic process is to be performed and a region where a pseudo halftone process is to be performed. Specific means are described, for example, in JP-A-63-316566. The determination result Fdm is binary data. Judgment result Fdm
Is different for each color, the output of the selector 700 becomes unstable, so that the character / photograph area determination is performed on the luminance data. In this example, as described above, the luminance data is substituted by the G data.

FIG. 11 shows an example of the mode designation code Fmod input from the input mode designation unit 100.

The selector 260 is driven by the above four types of code information. The selector 260 converts the binary image data of each of the three planes of RGB output from the binary processing section 240 and the dither processing section 250 into one to four of the four frame memories 310, 320, 330, and 340 based on the data of a total of six planes. Select binary data DTATA-1 to DATA-4 to be output.

 FIG. 12 shows an example of the operation content of the selector 260.

In the data output in the figure, Rc, Gc, and Bc are the binary processing results of R, G, and B output from the positioning processing unit 240 in FIG. 9, respectively, and Rd, Gd, and Bd are dither processing units. R, G, B output from 250
Are the binarization processing results. In the mode (I), only the luminance information is output, and only one of Gc and Gd is output to the frame memory 310. Here, switching between Gc and Gd is executed by the output Fdm of the character / photograph area determination unit 230. However, when the image to be input is composed of only one of a character and a photograph, it can be fixed to either one of the outside using the input setting unit 100 or the like, which will be described later.

In the mode (II), binary image data of two planes is stored in the frame memories 310 and 320. The selection of the data to be stored is determined by the output Fdm of the character / photo area determination unit 230.
Is controlled by the output Frb of the color identification unit 220. here,
DATA-1 contains Gc and G by Fdm as in mode (I).
Select and record one of d.

Also, this figure shows a case where 1-bit code data is used as Frb.

The identifier Frb is, if the target pixel is “red”,
Set to “1”, otherwise set to “0”. DATA-2 is Frb
Is "1", it becomes Gc or Gd, and if Frb is "0", DATA-2 becomes "0".

The switching between Gc and Gd is performed in the same manner as in mode (I).
Is selected by

Also in the mode (III), the image is stored as a binary image of R, G, B3 planes. Here, the stored data is R,
G and B planes.

On the other hand, in the mode (IV), R, G, B, and Fcm are stored in four frame memories 310, 320, 330, and 340, respectively. Here, one of the G plane and the luminance plane is selected and stored in the frame memory 320 based on the output Fcm of the color / monochrome discriminating unit 210. As described above, in this example, the G data and the luminance data are Since they are identical, there is usually no need to select. However, in a document in which character areas are mixed, the output of the binarization processing section 240 is selected for the monochrome line graphic area, and the dither processing section 250 selects the other selection. Therefore, one of Gc and Gd is selected according to the output Fcm of the color / monochrome identifying section 210.

The examples described so far have been based on the premise that the target document is a document in which characters and photographs are mixed. However, when inputting a document in which the entire document is composed of characters or photos, for example, by the input mode specifying unit 150,
In addition to (I)-(IV), [text], [photo], [mixed]
By specifying the type of the region, the operating condition of the selector 260 can be determined independently of the character / photo region determination unit 400. In this case, a signal from the input mode designating unit 150 to the selector 260 is added with four types of input mode selection codes and an identification code of 2 bits according to the target document.

FIG. 12 shows an example of an output code from input mode designating section 150 in this case. Basically, in each of the four types of modes, [character] for which dither processing is not selected, [photo] that must be selected, and [mixed] based on the output of character / photo area determination
Exists. However, in the case of [character], the output of the binarization processing unit 240 is normally stored. However, in mode (III) and mode (IV), it is necessary to reproduce an intermediate color.
The output of the binarization processing unit 240 is not accumulated for the color area. Therefore, modes (III) and (IV)
Then, the case where [character] is specified is excluded.

FIG. 14 shows an example of the operation of the selector 260 when [character] is specified here, and FIG. 14 shows an example of the operation when [photo] is specified.
Each is shown in Figure 15.

Next, an example of a method of storing data in each of the above-described recording formats will be described.

DATA stored in frame memories 310, 320, 330, 340
The binary data of -1, DATA-2, DATA-3, and DATA-4 are encoded by known means and then stored in a large-capacity data storage device such as an optical disk. An embodiment of the data storage portion will be described with reference to FIG. 310,320,330,340 in the figure
Is a frame memory for storing binary image data for each plane as described above, and 600 corresponds to the data storage section in FIG. The data storage unit 600 can be realized by the configuration described below. In the figure, reference numeral 610 denotes a selector for sequentially reading data in each connected memory and outputting the data to the code decoding processing unit 620. The encoding / decoding processing unit 620 encodes the binary data by a known means, and accumulates the data in the data accumulation unit 650 such as an optical disk.

When an instruction to store data is given from the control unit 900, the system first transfers and stores the header information to the optical disk 890. The header information includes, for example, information used at the time of search, such as a document name, and the size of the document. However, in the present invention, a mode at the time of input is recorded by a code or the like as one item of the header information.

After accumulating the header information, the binary image data of 1 to 4 planes are sequentially encoded by the encoding processing unit 620 and accumulated in the data accumulation unit 650 according to the mode. The order of the data to be stored is determined by the selector 610 according to an instruction from the control unit 900.
Is selected by

Here, the recording order of the data stored in the data storage unit 650 will be described with reference to FIG. Fig. 17 (a)-
(D) is an example of a recording format of data input in modes (I) to (IV). In the figure, 910 is an area for recording header information, 920 is DATA-1, and 930, 940, and 950 are DAs, respectively.
This is an area for recording TA-2, DATA-3, and DATA-4.

In the mode (I), the image data is only the luminance plane, and stores only DATA-1 in the frame memory 310. On the other hand, in modes (II) to (III),
As image data, a luminance plane is accumulated at the head, and thereafter, a plane is recorded for each color. In the case of expressing a plurality of colors in the mode (II), each plane is sequentially recorded after the luminance plane. As a result, when searching and displaying images, simply read out the first data,
It is also possible to output a monochrome binary image. On the other hand, in the mode (IV), G data is recorded at the head of the image data. This is because, among the three types of data, R data, G data, and B data, the spectral spectrum is located in the middle, so that the phenomenon that the specific color is not reproduced is most unlikely to occur. Therefore, in this case, when displaying, it is possible to output a monochrome binary image only by reading the first data.

On the other hand, code information indicating the mode at the time of inputting each image is recorded in the recording area 911 in the header information.

Next, a process of reading out image data recorded in the data storage unit 500 and displaying an image will be described.

First, the part of reading out the image data stored in the data storage unit 650 and inputting it to the frame memories 310, 320, 330, 340 will be described with reference to FIG. First, the header information of each data recorded in the data storage unit is read out, and the target data is searched.

If the target data is confirmed, then the number of planes to be read is determined by the mode identifier Fmod recorded in the header information, and the necessary data in the data storage unit 650 is read by the required number. However, after being decoded into binary data by the code decoding processing unit 620, the data is stored as DATA-1 to DATA-4 in the frame memories 310, 320, 330, and 340.

Next, DATA-1 to DATA-4 developed in the frame memories 310, 320, 330, and 340 are converted into data in a format suitable for input to the image display unit 500 such as a high-definition color CRT by the data conversion unit 400, and image display is performed. Displayed in section 500.

The operation of the data conversion unit 400 is to generate image data of three RGB planes from the input binary image data of one to four planes. Hereinafter, in this specification, data of R, G, and B reproduced from multi-valued information are referred to as DATA-R, DATA-G, and DATA-B. Where DATA−
The relationship between R, DATA-G, DATA-B and the colors displayed on the image display section 500 is the same as in FIG. DATA-R, DATA-G, DATA-B
If both are “1”, “white” is displayed, and if both are “0”, “black” is displayed.

Next, a configuration example of the data conversion unit will be described with reference to FIG. The data selector 410 in the figure is controlled by the control unit 900 according to the mode identifier Fmod in the read header information, and combines necessary data among DATA-1, DATA-2, DATA-3, and DATA-4, and -R, DATA-G, DATA-B are output.
The details of this operation will be described later. The RGB three-plane binary data output from the data selector 410 is converted into data in a format corresponding to the image display unit 500 by the multi-value processing unit 420. In this process, a value for controlling the blinking of each pixel of the image display unit is converted by binary data using, for example, a bit shift.

The operation of the data conversion unit depends on the mode of the target image,
It differs depending on the type of display and the content of the data.

FIG. 19 shows an example of the operation of the data selector 410. Here, for example, when an image in mode (II) is displayed in color, DATA-R, DATA-
G, DATA-B is determined. Only luminance information DATA-1 is "1"
In the case of, all of DATA-R, DATA-G, and DATA-B become "0" and "black" is displayed, and when DATA-1 and DATA-2 are "1", only DATA-R becomes "1". To display “red”.

On the other hand, the timing of displaying an image can be as follows. For example, when displaying a monochrome image, the luminance data Y is input to the frame memory 310, and at the same time, the luminance data is output from the data cell as RGB three-plane data. Then, the R, G, B
By sending image data of the same value to each plane to the image display unit 500, a monochrome image is displayed on the image display unit 500.
Displayed above.

On the other hand, when displaying a full-color image in mode (III), the values of DATA-R, DATA-G, and DATA-B are independently determined by DATA-1, DATA-2, and DATA-3. The timing of image display is DATA-1, DATA-2, DATA-
3 is written to the frame memory and at the same time
G, R, and B planes are displayed in order.

When displaying the image data of mode (II), the final color cannot be determined until the data of three planes is accumulated in the frame memories 310 to 330. In this case, it is also effective to first display the luminance data as a monochrome image in the same manner as in the mode (I), and to sequentially rewrite the luminance data.

On the other hand, according to an instruction from the control unit 900, the data selector 4
By controlling the operations of 10, it is possible to realize, for example, displaying a color image in monochrome. In particular,
For example, in the case of monochrome display, it can be realized by reading out only DATA-1 and displaying this DATA-1 for all of R, G and B.

Further, for example, only the red plane can be selected and displayed by displaying only DATA-2 of the image data of two planes of the multi-color document input in the mode (II).

By the way, the full-color image targeted for the mode (III) or (IV) originally needs to express shades in halftones. In particular, in color photographs and the like, a slight difference in color tone due to the characteristics of the output device is perceived as a great difference to human vision.

Therefore, in order to display a full-color image with high image quality, it is necessary to correct or change the luminance and chromaticity of the halftone data. In the present invention, since an image is stored as binary data, a means for converting binary image data into multi-valued data having shading is required to achieve the object.

FIG. 20 shows a configuration example of an image display unit for realizing the object. In this example, three types of binary data, DATA-R, DATA-G, and DATA-B, are simultaneously input and output to the image display unit 500. However, a memory for temporarily storing data is used. Can be converted one plane at a time.

In the figure, 431, 432, 433 are halftone converters for reproducing multi-valued data from binary image data, 441, 442, 443 are color tone converters for converting the obtained halftone data, and 451, 452, 453 are 2
A shift register for multiplying the value data by a specific value; 470, an area determining unit 461, 462, 463 for determining whether input data is binary halftone data such as a line figure or the like;
A selector for selecting one of two types of halftone data based on the output of 70, and an image display unit 500 for inputting RGB multi-value data and displaying a full-color image.

Here, for simplicity, the operation for one plane will be described, but the same applies to other planes. Here, the halftone conversion unit 431 reproduces multi-value halftone data from the pseudo halftone processed image. Although a large number of methods are already known as a reproducing means, for example, a method of extracting the distribution density of black pixels in a nearby local region, such as Japanese Patent Application No. 63-240973, can be applied. The halftone-converted image is subjected to necessary conversion by the color tone conversion unit for each of the RGB planes. The color tone conversion unit 441 can be represented by, for example, a RAM (Read Only Memory). In addition to setting the contents of the RAM in advance, a method of transferring the contents from the control unit or selecting the contents according to a plurality of types of internally set devices connected in advance can be realized.

On the other hand, in the area of a line figure such as a character, the positional relationship of black pixels is important, and expressing the shading rather deteriorates the resolution, thereby deteriorating the image quality. Therefore, for example, when the input range of the display unit 500 connected to the system is 8 bits, the input binary data is simply converted to 8 bits.
The shift prevents deterioration of image quality.

The selector 461 selects and outputs one of the outputs of the color tone conversion unit 441 and the shift register 421. The choice is
The area to be output is switched by the output of the area determination unit 470 that determines which of the line graphic area and the pseudo halftone area belongs to. As a means for determining the area of the input binary image, many methods are already known, and these methods are also used in this embodiment.

The image selected by the selector 461 is transferred to an image display unit 500 such as a CRT and displayed.

As a result, a halftone image such as a color photograph can be stored as binary data and then displayed as a halftone image. Further, conversion such as density and chromaticity can be performed.

In the present embodiment, an example of a method of simultaneously converting three planes of binary data has been described. However, the provision of the means for temporarily storing data allows each plane to be converted in turn. Although the case where the image is displayed on the CRT has been described as an example, the same method can be used for other output devices such as a printer.

〔The invention's effect〕

According to the present invention, it is possible to efficiently accumulate various types of document images irrespective of whether they are color documents or monochrome documents, in particular, images having a mixture of monochrome portions, which are common in color documents. For a color document whose area is mainly used and color reproduction is not important, a color image processing apparatus with higher encoding efficiency can be realized.

Further, it is possible to realize a color image processing apparatus that stores a color image in a data format compatible with the conventional image processing apparatus for monochrome images. At the same time, it is possible to realize a color image processing method for storing color image data in a format that maintains compatibility with monochrome image data that has been conventionally stored.

Further, even when a color image once stored is output, a color image processing apparatus capable of changing the color tone and saturation of the image can be realized. Further, for example, when retrieving the contents of color image data stored in large quantities on an optical disk or the like, an image processing apparatus capable of displaying the contents of each image at high speed can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an image data format when a multi-color document is stored, FIG. 2 is a diagram showing colors represented by respective data when a multi-color document is stored, and FIG. FIG. 4 is a diagram illustrating an image data format when a multi-color document including red and blue is stored. FIG. 4 is a diagram illustrating colors represented by respective data when a multi-color document including red and blue is stored. FIG. 6 is a diagram illustrating an image data format when a full-color document is stored. FIG. 6 is a diagram illustrating colors represented by respective data in a full-color mode. FIG. 7 is a diagram in which a color region and a monochrome region are mixed. FIG. 8 is a diagram for explaining a data format when a document is input, FIG. 8 is a diagram for explaining an overall outline of a system for realizing the present invention, and FIG.
FIG. 10 is a diagram showing an example of the configuration of a part for inputting a main image and converting it into binary image data. FIG. 10 is a diagram showing the types of data described in a frame memory in each mode. FIG. 11 is a diagram showing an example of code data indicating each mode instructed by the input mode designating section. FIG. 12 is a diagram showing the operation of each mode and the operation of the data selector for selecting data to be stored based on various area determination results. FIG. 13 is a diagram showing an example, FIG. 13 is a diagram showing an example of code data in the case of inputting an instruction for limiting a target area, in addition to an input mode by an input mode designating section, and FIG. Figure 15 shows the contents of data stored in each frame memory when the document to be input is limited to line graphics such as characters. Diagram showing the contents of data to be stored, FIG. 16 is a diagram for explaining a process of recording each image data in a large-capacity data storage unit such as an optical disk, and FIG. 17 is a diagram showing a storage procedure of image data of each mode recorded on the optical disk. , FIG. 18 is a diagram for explaining the process of displaying image data, FIG. 19 is a diagram for explaining the operation of the data selector in each state, FIG.
FIG. 3 is a diagram illustrating a configuration example of a multi-value processing section.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiromichi Fujisawa 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. In the factory (72) Inventor Tsugio Takahashi 2880 Kozu, Kokuzu, Odawara City, Kanagawa Prefecture Inside the Odawara Plant, Hitachi, Ltd. Yasuo 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Microelectronics Device Development Laboratory, Hitachi, Ltd. (56) References JP-A-63-197173 (JP, A) JP-A-63-199569 (JP, A) JP-A-62-188566 (JP, A) JP-A-63-232681 (JP, A) , A) JP flat 3-122678 (JP, A) JP flat 3-46869 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) H04N 1/40 - 1/409 H04N 1/46-1/64

Claims (15)

(57) [Claims] A scanner for optically reading and outputting an image; an input mode designating unit for entering a mode designating code; a first frame memory for storing binary image data;
Frame memory, a third frame memory, a fourth frame memory, and the scanner and the input mode designating unit, and identifies whether each pixel of the image from the scanner belongs to a color area or a monochrome area. Then, it is determined whether each pixel of the image from the scanner belongs to a predetermined specific color,
The image input from the scanner is converted into binary data, and the binary data is converted to the first frame memory, the second frame memory, the third frame memory, and the fourth frame memory. A data input unit that outputs the binary data based on an output, wherein the data input unit uses the binary data used as luminance information in the first frame memory according to a mode input from the mode designating unit. A first mode for storing data,
A second mode in which the binary data used as the luminance information in the first frame memory is stored in the second frame memory as the binary data which is color pixel information to be displayed in a predetermined color; Storing the binary data as color pixel information of the three primary colors in the frame memory, the second frame memory, and the third frame memory, respectively.
Mode, the monochrome area stores the binary data as luminance information in the first frame memory, and the color area stores three primary colors in the first frame memory, the second frame memory, and the third frame memory, respectively. A fourth mode in which the binary data as color pixel information is stored, and an area identifier indicating whether each pixel is a monochrome area or a color area is stored in a fourth frame memory. Color document image processing device. 2. A color document image processing apparatus according to claim 1, wherein said binary data as color pixel information of said three primary colors is binary data composed of three planes of RGB. 3. The color document image processing device according to claim 1, wherein the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designation unit A binary data stored in the first frame memory, the second frame memory, the third frame memory, and the fourth frame memory is specified by the input mode specifying unit. Color document image processing device stored according to the mode performed. 4. A color document image processing apparatus according to claim 3, wherein a mode specified by said input mode specifying unit is recorded as one item of header information on a storage medium of said data storage unit. Processing equipment. 5. The color document image processing device according to claim 1, wherein the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designating unit are A data conversion unit connected thereto and an image display unit connected to the data conversion unit, wherein the first frame memory, the second frame memory,
The binary data read from the third frame memory and the fourth frame memory is converted into data in a format suitable for input to the image display unit by the data conversion unit according to the mode, and the image display unit A color document image processing device for displaying an image based on the output of the data conversion unit. 6. A scanner for optically reading and outputting an image, an input mode specifying unit for inputting a mode specifying code, a first frame memory, a second frame memory, and a third frame for storing binary data. A color / monochrome identifying section for identifying whether each pixel of the image from the memory and the fourth frame memory and the scanner belongs to either the color area or the monochrome area; and a predetermined specific pixel for each pixel of the image from the scanner. A color identification unit that determines whether the pixel belongs to a color; and a character / photo region determination unit that determines whether each pixel of the image from the scanner belongs to a character or other line graphic region or a photograph or other halftone region. A binarization processing unit that performs binarization when an image from the scanner is in the line graphic area; and a pseudo halftone that performs binarization when the image from the scanner is in the halftone area. A processing unit; a first frame memory for storing binary image data;
A frame memory, a third frame memory, and a fourth frame memory, the color / monochrome identifying section, the color identifying section, the character / photograph area determining section, the binarizing section, and the pseudo halftone processing section. And the binary data output from the binarization processing unit or the pseudo halftone processing unit,
And a first selector for selecting and outputting the binary data to the frame memory, the second frame memory, the third frame memory, and the fourth frame memory, wherein the first selector A first mode for storing the binary data used as luminance information in the first frame memory according to a mode input from the mode designating unit; If it is determined that the pixel does not belong to a specific color, the binary data used as luminance information is stored in the first frame memory, and each pixel is
If it is determined that each pixel of the color identification unit belongs to a predetermined specific color, the binary data used as luminance information is stored in a first frame memory, and color pixel information of the specific color is stored in a second frame memory. A second mode in which the binary data is stored, and each pixel determines that the color / monochrome identifying section belongs to a monochrome area, and the character / photograph area determining section belongs to a character or other line / graphic area. If it is determined that the color data to be used as the luminance information among the three primary colors is accumulated in the first frame memory, the second frame memory, and the third frame memory, each pixel If the color / monochrome identifying unit determines that the image belongs to a monochrome area and the character / photograph area determining unit determines that the image belongs to a photograph or other halftone area, If it is determined to belong to the area, the first frame memory,
A third mode in which the binary data, which is color image information of the three primary colors, is stored in the second frame memory and the third frame memory; If the character / photograph area determination unit determines that the character / photograph area belongs to a character or other line / graphic area, the first
The binary data of the color to be used as the luminance information among the three primary colors is stored in the frame memories of the three primary colors, and “0” is stored in the second frame memory, the third frame memory, and the fourth frame memory. However, when the color / monochrome identifying section determines that the image belongs to a monochrome area and the character / photograph area determining section determines that the image belongs to a photograph or other halftone area, If it is determined that the image data belongs to the area, the binary data, which is the color image information of the three primary colors, is stored in the first frame memory, the second frame memory, and the third frame memory.
A fourth mode in which "1" is stored in the frame memory of the color document. 7. A color document image processing apparatus according to claim 6, wherein said binary data as color pixel information of said three primary colors is binary data composed of three planes of RGB. 8. The color document image processing apparatus according to claim 6, wherein the first selector is configured to determine whether the character / photograph area determination unit is a character or other character in the first mode and the second mode. When it is determined that the image belongs to the line graphic area, the output of the binarization processing unit is determined. When the character / photograph area determination unit determines that the output belongs to the photograph or other halftone area, the output of the pseudo halftone processing unit is determined. Outputting the output to a first frame memory and a second frame memory; in the third mode and the fourth mode, the color / monochrome discriminating unit determines that the color / monochrome identification unit belongs to a monochrome area; and If the character / photograph area determination unit determines that the color / monochrome identification unit belongs to a monochrome area, the output of the binarization processing unit is determined to belong to a character or other line graphic area; and Text / photo area format If it is determined that the unit belongs to a photograph or other halftone area, and if the color / monochrome discriminating unit is determined to belong to a color area, the output of the pseudo halftone processing unit is stored in a first frame memory. A color document image processing device for outputting to a second frame memory and a third frame memory. 9. The color document image processing device according to claim 6, wherein the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designation unit A binary data stored in the first frame memory, the second frame memory, the third frame memory, and the fourth frame memory is specified by the input mode specifying unit. Color document image processing device that accumulates according to the mode performed. 10. A color document image processing apparatus according to claim 9, wherein: on a storage medium of said data storage section,
A color document image processing apparatus for recording a mode specified by the input mode specifying unit as one item of header information. 11. The color document image processing apparatus according to claim 6, wherein: the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designating unit Connected, the mode and two of the first frame memory, the second frame memory, the third frame memory and the fourth frame memory.
Second output of binary data of three primary colors based on the value data
A multi-value processing unit that is connected to the second selector and converts data output from the second selector into data for displaying an image, and is connected to the multi-value processing unit. A color document image processing apparatus having an image display unit for displaying an image based on data output from the multi-value processing unit. 12. The color document image processing apparatus according to claim 11, wherein the multi-value processing section is configured to determine whether the binary image data from the second selector is in a line graphic area or in a halftone area. An area determination unit that determines whether the data is located in a halftone area; and a halftone conversion unit that reproduces multilevel halftone data from data in a halftone area, among binary image data from the second selector. A tone conversion unit that converts halftone data from the halftone conversion unit; a shift register that passes data in a line graphic area among binary image data from the second selector; And the tone conversion unit and the shift register, the area determination unit selects data from the shift register when it is determined to be in the line graphic area, and when it is determined to be in the halftone area, A color document image processing apparatus having a third selector for selecting data from the color tone conversion unit. 13. A scanner for optically reading and outputting an image, an input mode specifying unit for inputting a mode specification code, a first frame memory for storing binary image data, and a second frame memory for storing binary image data.
Frame memory, a third frame memory, a fourth frame memory, and the scanner and the input mode designating unit, and identifies whether each pixel of the image from the scanner belongs to a color area or a monochrome area. Then, it is determined whether each pixel of the pixels from the scanner belongs to a predetermined specific color,
The image input from the scanner is converted into binary data, and the binary data is converted to the first frame memory, the second frame memory, the third frame memory, and the fourth frame memory. A data input unit for outputting the binary data based on an output, wherein the data input unit stores the binary data, which is luminance information, in the first frame memory in the monochrome area, and stores the binary data in the first frame memory. The first frame memory, the second frame memory, and the third frame memory store the binary data, which is color pixel information of the three primary colors, and the fourth frame memory stores each pixel in a monochrome area or a color area. A color document image processing apparatus having a mode for storing an area identifier indicating whether the color document is stored in the image processing apparatus. 14. The color document image processing device according to claim 13, wherein the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designating unit are A data storage unit to be connected, wherein the data storage unit stores the binary data in the first frame memory when an output of the fourth frame memory is an identifier indicating a monochrome area; The fourth
A color document image processing device that stores binary data of the first frame memory, the second frame memory, and the third frame memory when the output of the frame memory is an identifier indicating a color area. 15. The color document image processing device according to claim 13, wherein the first frame memory, the second frame memory, the third frame memory, the fourth frame memory, and the input mode designating unit are A data conversion unit connected to the data conversion unit; and an image display unit connected to the data conversion unit. When the data conversion unit is an identifier indicating that the output of the fourth frame memory is a monochrome area, The data conversion unit converts the binary data of the first frame memory into monochrome image data in a format suitable for input to the image display unit, and outputs the monochrome image data.
When the output of the frame memory is an identifier indicating a color area, the input of the image display unit is based on the binary data of the first frame memory, the second frame memory, and the third frame memory. A color document image processing apparatus that converts the image into color image data in a format suitable for the image data and outputs the image, and the image display unit displays an image based on the output of the data conversion unit.