JP2773079B2 - Color image processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a simple type electrophotographic color copying machine and the like, and is preferably a color image processing apparatus, particularly, a halftone image so as not to overlap an image area. The present invention relates to a color image processing apparatus capable of performing processing.

BACKGROUND OF THE INVENTION Color image information such as a document is optically read and separated into a plurality of colors such as black, red, and blue, and based on this, an output device such as an electrophotographic color copier is used. A color image processing apparatus for recording on recording paper is disclosed in
57-147374 and JP-A-58-62769.

In such an image processing apparatus, when image processing such as shading is performed on a specific image area, processing as shown in FIG. 11 is normally performed.

FIG. 7A is an example of a halftone image in which a halftone dot is recorded over a predetermined area in the character image of “a”.

As is apparent from FIG. 6, when halftone dots are applied over a predetermined area, halftone images are formed for all the specified areas. Therefore, this halftone dot is also formed inside the image area.

Halftone dots can be formed in color. In this case, a halftone dot can be formed in the same or different color as the color of the image existing in the area.

[Problems to be Solved by the Invention] By the way, in such a color image processing apparatus,
When the above-described shading process is performed, a halftone dot pattern is formed so as to be formed in all of the specified specific area. Would.

In this case, when a black halftone dot is recorded for a black-and-white image, when a halftone dot is recorded in a color different from the color of this image for a color image, the overlapping portion is not recorded. It becomes very unsightly and the color image quality is significantly degraded.

In view of the above, the present invention solves such a conventional problem with a simple configuration, and particularly proposes a color image processing apparatus capable of forming a halftone dot so as not to overlap with an image. .

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention,
In a color image processing apparatus configured to form a shading pattern on an original image within or outside a region designated by a marker in advance, color separation of image data based on the original image into a plurality of colors. And at least,
A color image processing means for performing color image processing on the original image, an area extracting means for extracting the inside or outside of the designated area from the original image by the color image processing means, and a network in the area extracted by the area extracting means. Shading means for outputting shading data for forming a shading pattern, and for each pixel in the area extracted by the area extracting means,
If there is image data of the original image, the image data is selectively output by the color image processing means, and each pixel in the area extracted by the area extracting means (hereinafter also referred to as an area extracting circuit 500) is used to output the image of the original image. If there is no data,
And a selection circuit for selectively outputting hatched data by the hatching means.

[Operation] According to the color image processing apparatus of the present invention, when forming a hatched pattern in or outside a region designated by a marker in advance on an original image, the image in the designated region is In each pixel, when there is image data of the original image, the image data by the color image processing means is selectively output, and in each pixel in the area, when there is no image data of the original image, shading means The hatching data is selectively output.

With this configuration, when the image data of the original image is present in the designated area, for example, the color discriminating circuit, the color ghost correction unit, the filtering correction unit, and the enlargement / reduction processing unit that constitute the color image processing unit are used. The original image is reproduced and formed in color only by the passed image data. When there is no image data of the original image in the designated area, shading is performed by a shading means (hereinafter also referred to as a shading processing circuit 440). A hatched pattern can be reproduced in color by data. Thereby, color reproduction can be performed on the original image so that the hatched pattern does not overlap the original image that has been marked in advance.

Image information of a document optically captured is separated into a plurality of colors. The color-separated image information is photoelectrically converted by a reading unit such as a CCD.

The photoelectrically converted image signal is separated into color information and density information of the image. Image processing such as color ghost correction is performed on the color information.

Enlargement / reduction processing, resolution processing,
Various image processing such as processing (extraction, deletion, etc.) inside / outside a specific area is performed.

Shading is also a type of image processing. Halftone dots are recorded excluding the image existing in the designated area. In this case,
Since no halftone dot is recorded in the outline of the image, the image quality does not deteriorate even when the image and the halftone dot are recorded in color.

In this example, the following processing is executed to perform image processing.

First, detection processing of the attribute designation signal P is performed on the color ghost corrected image data.

The attribute designation signal P refers to a signal corresponding to a case where the original is a line image by determining the contents of the original and a case where the original is a photographic image. Using this signal P, a filter coefficient for resolution correction (MTF correction) and a threshold value for multi-value processing are changed.

In order to extract a specific area, a color marker is attached to the original, and image data inside or outside the area surrounded by the color marker is extracted by an area signal obtained by automatically extracting the color marker.

The area signal and the above-described attribute designation signal are collectively referred to as a control signal for an image.

This control signal is also subjected to the same enlargement / reduction processing as the image data in the enlargement / reduction processing. Thus, image processing of a specific area can be performed even in the enlargement / reduction processing mode.

 Color processing is performed in addition to the image processing described above.

Color processing is a process of erasing specific color information and recording the remaining image information with the color of the image information, or replacing the specific color information with another specified color and the image area Or the process of recording

This color processing is also possible for image data that has been enlarged / reduced.

Image processing and color processing are performed in the order of recording colors of the developing device. The order of recording is to achieve simplification of image processing and color processing.

When the developing device records one color for each rotation of the photosensitive drum in the order of red → blue → black, the red image is developed in the red copy sequence, and all the colors are processed. The fixing process is performed at the stage when the developing process for is completed, and the color copy is completed.

Which color image is valid or invalid is determined by external designation.

After various types of image processing and color processing are completed, multi-value processing is performed. The image is visualized based on the signal subjected to the multi-value processing.

Since image processing is performed before multi-level conversion,
Even if a reduction process is performed, there is no possibility that the image quality is degraded.

[Example] Hereinafter, an example of a color image processing apparatus according to the present invention will be described.
This will be described in detail with reference to FIG.

FIG. 1 shows a schematic configuration of a color image processing apparatus according to the present invention.

The color image information (optical image) of the document 52 is separated by the dichroic mirror 55 into two color separation images. In this example, the color separation image is separated into a red R color separation image and a cyan Cy color separation image. Therefore, the cutoff of the dichroic mirror 55 is about 540 to 600 nm. by this,
The red component becomes transmitted light, and the cyan component becomes reflected light.

Each color separation image of red R and cyan Cy is supplied to image reading means, for example, CCDs 104 and 105, and each outputs an image signal of only the red component R and cyan component Cy.

The image signals R and Cy are supplied to the A / D converters 60A and 60B to be converted into digital signals of a predetermined number of bits, in this example, 6 bits. Shading correction is performed simultaneously with A / D conversion. 15A and 15B show shading correction circuits.

Only the signal of the maximum document size width is extracted by the effective area extraction circuit 30 from the digital image signal subjected to the pseudo correction, and is supplied to the color discrimination circuit 35 at the next stage. When the maximum document width to be handled is B4 size, the size signal B4 generated by the timing signal forming means (not shown) of the system is used as the gate signal.

Here, assuming that the shading-corrected digital image signals are VR and VC, respectively, these image signals VR and VC are supplied to a color discrimination circuit 35 and discriminated into a plurality of color signals.

In this example, a case is illustrated in which the color signal is configured to be distinguished into three color signals of red, blue, and black. In other words, regardless of the color of the document, one of red, blue, and black is assigned to one color for each pixel. When this process is performed, each portion of the document is recognized as a portion of any of red, blue, and black colors. It should be noted that setting the red, blue, and black to other colors, and further setting four or more colors are also included in the color discrimination processing.

In this example, a color discrimination map (bipolar ROM configuration) as shown in FIG. 6 is used for the color discrimination processing.

FIG. 1 shows a case where color information for color marker discrimination is also mapped so that a color marker marked on a document can be discriminated.

At the address given by the 6-bit image data VR and VC, a 3-bit color code (designating red, blue, black, red marker, blue marker, and white marker) and 6-bit density information are stored. I have.

 That is, one image information = color code + density information.

For example, the density value is 30 levels in hexadecimal notation Similarly, blue = 001011110 = 5E black = 000011110 = 1E white = 011011110 = DE red marker = 101011110 = 15E blue marker = 110011110 = 19E.

 FIG. 7 shows an example of the color code data.

The color-separated image data is transferred to a color image processing step.

First, the color ghost is supplied to the next-stage color ghost correction unit 300 to correct the color ghost in the main scanning direction (horizontal scanning direction) and the sub-scanning direction (drum rotation direction).

This is because unnecessary color ghosts (color ghosts) such as red or blue may occur at the edge portion of black characters, particularly at the time of color discrimination.

Eliminating these color ghosts improves image quality. The color ghost processing is performed only on the color code data.

Also in the case of copying in monochrome, for example, when a function of copying by erasing a colored portion is required, a color ghost correction circuit as in this example is required.

300A shows a color ghost correction circuit in the main scanning direction,
Reference numeral 300B denotes a color ghost correction circuit in the sub-scanning direction.

When performing color ghost correction using image data for 7 bits in the horizontal direction and 7 lines in the vertical direction, a 7-bit shift register 301 and a memory 310 for 7 or 8 lines are used, respectively, as shown in the figure. Will be done.

After the color ghost-corrected image data passes through a buffer line memory, in this example, a three-line memory 799, various image processes are executed.

As image processing, in addition to color ghost correction, filtering means (MTF correction means) 450, specific area extraction / deletion / filling means 420, enlargement / reduction processing means (magnification means) 1, shading processing according to the present invention Means 440, inversion means 4
60, various image processing such as multi-level conversion means 600 for multi-level conversion can be considered.

Of these image processing, the filtering means 450 changes the filter coefficient according to the image content, thereby obtaining a sharper image.

Similarly, it is preferable that the multi-value conversion unit 600 also changes the threshold for multi-value conversion according to the image content.

In order to change the filter coefficient or the multi-value threshold, it is necessary to recognize whether the image currently being read is a line image but a photographic image.

Therefore, an attribute detecting means 800 for detecting such an attribute of the image is provided at the subsequent stage of the three-line memory 799,
The filter coefficient and the threshold are changed according to the attribute designation signal P obtained from this.

The determination of whether the target pixel is a character image or a photographic image is performed using information on the density level difference between the upper and lower neighboring pixels and the right and left pixels and the target pixel.

i is the coordinates of the pixel in the main scanning direction, j is the coordinates of the pixel in the sub-scanning direction, and X, Y, and Z are the pixels (i, j), (i−1,
j), (i, j-1), the density level difference t is calculated by the following equation.

t = | X−Y | + | X−Z | Then, when t> q, it is determined as a line drawing, and when t <q, it is determined as a photographic image.

Here, q is a constant and is set to an arbitrary value among q = 3 to 10 levels. According to experiments, it is preferable that q = about 5.

On the other hand, the density data and the color code data subjected to the color ghost correction are first supplied to the filtering means 450, where the filtering (MTF correction) processing is performed.

The reason for performing the MTF correction is that the sub-scanning direction (the direction of rotation of the drum of the image forming body, which will be described later) is obtained in the sub-scanning direction compared to the main scanning direction (the scanning direction of the optical signal) in order to obtain a signal by integrating the optical signal. This is due to significant deterioration of MTF.

By performing the MTF correction process, it is possible to correct the character jump and crush.

MTF correction is performed using a 3 × 3 convolution filter.

The MTF-corrected image data is processed by the processing unit 420.
Extraction / deletion / painting processing for a specific area is executed.

Since these processes are all performed within or outside a specific area, it is necessary to detect a specific area in order to perform these processes.

The detection of the specific area is performed based on a marker written on the document.

An area extraction circuit 500 is provided to detect an original image area marked by a color marker on a document or the like.

The region extraction process is a process for extracting a designated region so that various types of image processing can be performed on an image (black image) inside or outside an arbitrary region designated by a color marker. is there.

The area extraction circuit 500 outputs a signal (area signal) S indicating the inside / outside of the area surrounded by the color markers.

 FIG. 8 shows a specific example of the area extracting circuit 500.

In the figure, each bit data of color code data obtained by scanning a color marker is supplied to a color marker detection circuit 501, and the presence or absence of a specific color marker is detected. In this embodiment, two marker signals BP, RP are detected because two types of markers, red and blue markers, are applied. The respective marker signals RP, BP are supplied to the pre-processing circuits 502, 503, respectively, and are sent to the command area. It is pre-processed to be a faithful marker signal.

The pre-processing is a kind of signal waveform shaping processing. In the embodiment, the blur correction circuits 504 and 507 and the noise correction circuits 505 and 5
Preprocessing circuits 502 and 503 are composed of the marker cutout correction circuits 506 and 509 in 08 (in both the main scanning direction) and the sub-scanning direction. The blur correction of the color marker corrects the blur within 16 dots / mm, and the noise correction corrects the lack of data within 8 dots / mm.

The waveform-shaped marker signals RP and BP are supplied to the area extracting unit 520 together with the color code data, and an area signal indicating the inside of the designated area a is output for each scanning line.

Actually, a gate signal for density data extraction is created based on this area signal, and density data is extracted by this gate signal. Here, for the sake of convenience, the description will be made with the area signal as a gate signal.

A partial color conversion process will be described as an application of the marker region detection process.

This conversion processing refers to processing in which an arbitrary area written with a marker can be copied with the color of the marker or another designated color.

For example, when an area a is designated by a blue marker as shown in FIG. 9, the area a is automatically detected, and the image included in the area a is copied in the marker color blue. Outside the area a is a normal copy. The color marker may be a red marker. The document to be subjected to the partial color conversion is a color document.

In order to copy the image in the area a specified in this way with the specified color, marker signals BP and RP (actually color code data) indicating the area of the color marker as shown in FIG. The area signals QB 'and QR' indicating the area a are detected respectively, and these are used as the area signal S.

Whether to use the inside or outside of the area signal S is selected by a marker inside / outside designation signal. The area signal S is further controlled by a full screen / partial screen designation signal.

These signals are specified from the display / operation unit,
A BBR signal indicating a color that must be captured and output at present is input, and a processing designation signal is output for image processing.

For example, when simply copying, only image data having the same color as the BBR signal is output.

When performing color conversion on the entire document, for example, when trying to convert red to blue and blue to red, respectively, first output red image data when recording blue, Is controlled so as to output blue image data when recording is performed.

When partially performing color conversion, black information in an area surrounded by a color marker is recorded in the color of the marker.

For example, if the black information in the area surrounded by the red marker is controlled to be output during the phase of recording red, the black information is recorded as red information. Can be recorded.

For such partial color conversion and color designation processing, when developing a color, use a developing system that rotates the drum for each color, develops the image, and starts the fixing process after the end of the development of the final color. It becomes possible for the first time.

In this case, the imaging operation is also performed a plurality of times. As described above, the image processing operation is simplified by performing the imaging operation and the developing operation for each color a plurality of times in the order of the recording colors.

Further, the image recording processing operation in that case can be performed in real time. The memory for storing images can be reduced by real-time processing.

A signal (region signal) S indicating a region surrounded by a color marker is output from the region extraction circuit 500 in the order of recording colors, and this signal is subjected to signal processing means 42 for extracting / erasing / filling.
Enter 0.

Here, extraction and extraction are performed according to the signal of the area extraction.
A signal for erasing and filling is created. At this time, the area signal is created in accordance with an instruction for inside / outside the marker area, designation of the entire area or partial processing, or the like.

 An example of signal processing is shown below.

1) No processing When the recording color is "red", only red is specified by a color code, and only "red" pixels are determined as an area to output image data.

 Same for blue / black.

2) Color erasure When performing “blue” erasure, if the development order is red → blue → black, no blue image data is output when the recording color is blue.

3) In-marker designation It is determined whether or not the marker is a marker by looking at the upper one bit of the color code.

When red → blue → black in the order of development, a marker is detected at the time of red recording, and image data is output at a position corresponding to the color code of red inside the marker.

When outside the marker, the same processing is executed outside the marker.

Also when performing achromatization, the area signal S is created from the color code data.

Next, this signal is supplied to the enlargement / reduction circuit 1 which is a scaling process via the input buffer 400, and is subjected to enlargement / reduction processing as required.

The data necessary for the enlargement / reduction processing includes an area signal S and an attribute designation signal P in addition to the density data output from the processing means 420.

The reason why the area signal S and the like are enlarged / reduced in addition to the density data is as follows.

That is, since the area signal S and the attribute designation signal PB are used in the shading processing or the hollowing-out processing even after the enlargement / reduction processing, the control signal such as the area signal S is also scaled with the density data. Scale according to the
This is because it is necessary to match the number of data to the designated magnification in advance.

The CPU sets a magnification instruction for the enlargement / reduction circuit 1.

The enlargement / reduction processing is performed by electrical processing in the main scanning direction, and is performed by controlling the scanning speed of the optical system in the sub-scanning direction.

After performing these processes on the required area, the image data is input to the shading circuit 440. Here, the necessary area is shaded. Details will be described later.

The reason why the shading is performed at the stage when the enlargement / reduction processing is completed is to make the pitch of the designated halftone unchanged after the enlargement / reduction processing.

The shaded image data is then converted to multi-value processing means 600.
And is subjected to multi-value processing.

The threshold value used for multi-value conversion is set manually or automatically.

In automatically determining the threshold value based on the input image data (density data), in the embodiment, the threshold value for character (for line drawing) and the threshold value for photographic image are different ROM600B, 600C.
Shows the case where it is stored in

600B is a ROM for characters, and 600C is a ROM for dithering a photographic image. Further, in this example, a fixed ROM 600D is used as a character image.

In addition, when the multi-value processing is performed in such a manner that white, black and gray (light gray and dark gray) are converted into four levels,
The respective thresholds Ti (i = 1 to 3) for multi-value quantization are selected.

Therefore, the threshold data T1 to T3 corresponding to each color are output from each of the ROMs 600B to 600D.

One of the thresholds is selected by the data selectors 600E to 600G.

Therefore, the attribute designation signal P output from the enlargement / reduction processing means 1 is supplied to the control circuit 600H.

The control circuit 600H selects the selectors 600DE to 600G based on the attribute designation signal P except when the processing content is designated externally.
Will be selected.

In the external specification, the threshold ROM 600B or 600D is selected when a character image is specified, and the threshold ROM 600C is selected when a photographic image is specified.

Based on the selected threshold value, the density data is subjected to multi-value processing in the multi-value conversion means 600A. As the multiple values, 2 to 5 values are appropriate, and in this example, a case of 4 values is shown.

The image data multi-valued by the multi-value converting means 600A is supplied to a blanking processing circuit 470 via a 9-line memory 459 which is a delay means.

The hollowing-out process is a process of extracting outline data of an image. In this example, only data of a 4-dot width of an edge of an image is extracted in the main scanning direction and the sub-scanning direction by external designation. Is performing processing.

The image data that has been subjected to the blanking processing is then input to an inversion circuit 460, and the inversion of the negative / positive is performed only in the necessary area according to the inversion command.

After that, the output device 70 via the interface circuit 40
Supplied to

As the output device 70, a laser recording device (laser printer) or the like can be used. In the case of using a laser recording device, the multi-valued image is converted into a predetermined optical signal, Modulated based on the value data.

As the developing device used in the output device 70, an electrophotographic color copying machine is used. In this example, two-component non-contact jumping development and reversal development are employed.

That is, the transfer drum used in the conventional color image formation is not used. In the embodiment, in order to reduce the size of the apparatus, a three-color image of blue, red and black is developed on an OPC photosensitive member (drum) for image formation by three rotations of the drum, and the transfer after development is performed by one rotation.
And transfer it to recording paper such as plain paper.

 Therefore, according to the color image processing apparatus shown in FIG. 1, appropriate image processing can be performed for each color with respect to multiple colors. Processing such as achromatization can be performed.

-Color conversion is possible.

・ Multi-value recording can be used to achieve high image quality. ・ It is possible to realize a device with features such as low cost.

Next, the configuration of each unit of the color image processing apparatus according to the present invention thus configured will be described in detail.

First, a simplified color copying machine suitable for application to the present invention will be described with reference to FIG.

A simple type color copying machine intends to record color images by decomposing color information into about three types of color information.
In this example, black B is used as three types of color information to be color-separated.
K, red R and blue B are exemplified.

The original reading unit A is driven by turning on the copy button of the apparatus.

First, the document 52 on the document table 81 is optically scanned by the optical system.

This optical system includes a carriage 84 provided with a light source 85 and a reflection mirror 87, and V mirrors 89 and 89 '.

The carriage 84 and the V mirrors 89, 89 'are caused to run on the slide rail 83 at predetermined speeds and directions by a stepping motor 90, respectively.

As the light source 85, a halogen lamp, a commercially available fluorescent lamp, or the like is used. In the embodiment, a halogen lamp is used.

Optical information (image information) obtained by irradiating the original 52 with the halogen lamp 85 is reflected by the reflecting mirror 87 and the V mirrors 89 and 89 '.
Through the optical information conversion unit 100.

A standard white plate 97 is provided on the upper left side of the platen glass 81. This is for normalizing the image signal to a white signal by optically scanning the standard white plate 97.

The optical information conversion unit 100 has a lens 801 and a prism 80
2.CCD 104 on which dichroic mirror 55 and red color separation image are projected, and CCD 105 on which cyan color separation image is projected
It is composed of

An optical signal obtained from the optical system is condensed by a lens 801 and color-separated into red optical information and cyan optical information by a dichroic mirror 55 provided in the prism 802 described above.

Each color separation image is formed on the light receiving surface of each CCD, so that an image signal converted into an electric signal is obtained.
After the image signal is processed by the signal processing system, each color signal is output to the writing unit B.

As shown in FIG. 1, the signal processing system includes a signal processing circuit such as a color separation unit and a multi-value conversion unit in addition to the A / D conversion unit.

The writing section B has a deflector 935. As the deflector 935, a deflector including an optical deflector using crystal or the like may be used in addition to a galvanometer mirror, a rotating polygon mirror, or the like. The laser beam modulated by the color signal is deflected and scanned by the deflector 935.

When deflection scanning is started, beam scanning is detected by a laser beam index sensor (not shown), and beam modulation by a first color signal (for example, a blue signal) is started. The modulated beam is scanned by the charger 121 on the image forming body (photosensitive drum) 110 to which uniform charging is applied.

Here, the main scanning by the laser beam and the image forming body 110 are performed.
The first scanning is performed on the image forming body 110 by
An electrostatic image corresponding to the color signal is formed.

This electrostatic image is developed by a developing device 123 containing blue toner. A predetermined bias voltage from a high voltage source is applied to the developing device 123. A blue toner image is formed by development.

The toner supply of the developing unit 123 is controlled by a toner supply unit (not shown) based on a command signal from a CPU (not shown) for system control, so that toner is supplied when necessary. become.

The blue toner image is rotated in a state where the pressure of the cleaning blade 127 is released, and an electrostatic image is formed based on a second color signal (for example, a red signal) in the same manner as in the case of the first color signal. Is used to develop a red toner image.

It goes without saying that a predetermined bias voltage is applied to the developing device 124 from a high-voltage power supply.

Similarly, an electrostatic image is formed based on the third color signal (black signal), and the developing device 125 filled with black toner causes the electrostatic image to be formed.
It is developed in the same way as the previous time.

Therefore, the multicolor toner image has been written on the image forming body 110.

Here, the formation of a three-color multicolor toner image has been described, but it goes without saying that a two-color or single-color toner image can be formed according to a designated recording mode.

As described above, in the state where the AC and DC bias voltages are applied from the high-voltage power supply,
An example of so-called non-contact two-component jumping development in which each toner is caused to fly toward the image forming body 110 for development has been described.

As described above, a predetermined amount of toner is supplied to the developing units 124 and 125 based on a command signal from the CPU.

On the other hand, the recording paper fed from the paper feeding device 141 via the feed roll 142 and the timing roll 143 is the image forming body 1
With the rotation and timing of 10 synchronized, the image forming body
Conveyed over the surface of 110. Then, the multicolor toner image is transferred onto the recording paper by the transfer pole 130 to which a high voltage is applied from the high-voltage power supply, and is separated by the separation pole 131.

The separated recording paper is conveyed to a fixing device 132, where a fixing process is performed to obtain a color image.

The image forming body 110 after the transfer is cleaned by the cleaning device 126, and is prepared for the next image forming process.

In the cleaning device 126, in order to facilitate collection of the toner cleaned by the blade 127,
A predetermined DC voltage is applied to a metal roll 128 provided on 127. The metal roll 128 is arranged in a non-contact state on the surface of the image forming body 110.

After the cleaning, the blade 127 is released from the pressure contact.However, at the time of the release, an auxiliary cleaning roller 129 is further provided to remove unnecessary toner left behind, and the roller 129 is rotated in the opposite direction to the image forming body 110, and the pressure is released. By doing so, the unnecessary toner is sufficiently cleaned and removed.

Note that the sheet feeding device 141 is provided with a sensor 65a, and the detection output is sent to the CPU.

FIG. 2 is a system diagram showing an example of a shading processing circuit 440 according to the present invention, in which image data subjected to enlargement / reduction processing is shaded.

The shading processing circuit 440 has a shading pattern ROM 441, and data for necessary shading processing is read by referring to the column address and the row address.

Therefore, a column counter 442 and a row counter 443 are provided, and the column address of the ROM 441 is specified by a counter output incremented by a signal corresponding to the B4 size. Similarly, a clock CK synchronized with one pixel (one pel)
The row address of the ROM 441 is specified by the counter output incremented by.

The halftone pattern data obtained by the address designation is supplied to the gate circuit 444, and the following gate processing is executed.

That is, the inside of the specific area specified by the color marker is shaded. A halftone dot is illustrated as the shading. In the case of dot recording, control is performed such that dots are recorded only in an area of the designated area where no image is recorded. That is,
11 As shown in FIG. B, halftone dots are recorded so as not to overlap with the character image.

Therefore, the gate circuit 444 includes an OR circuit 445 and a switching circuit 446, and the OR circuit 445 is supplied with shading data and image data. The OR output and the image data are selected by the switching circuit 446.

In this case, image data is selected in the image area, and OR output is selected in other specified areas.
In this case, the image area is recorded only by the image data, and the rest is recorded by the halftone dots, so that the image and the halftone dots are not overlapped and recorded (see FIG. 11B).

The image area and the non-image area are determined by a color code and a color code (character color code) indicating a character color indicating image data. Therefore, the color code and the character color code are supplied to the matching circuit 447, and when both codes match, it is regarded as a character color portion (image area). Therefore, this coincidence output is supplied to the switching circuit 446 as a switching pulse.

The image data output from the gate circuit 444 is output when the data selector 448 matches the copy sequence of the designated color. That is, when there is a color specified specifically for shading, a color code for shading is supplied to the control terminal 449 so that a halftone dot is recorded in that color. When the image data is output.

For example, when a halftone dot is to be recorded in the same color (color) as the color marker, the color may be designated. In this case, only when the color code matches the designated color code, the image data for the selected halftone dot is output.

The repetition of address designation for the ROM 441 is determined by the repetition period of the halftone pattern.

For example, when an 8 × 8 halftone pattern as shown in FIG. 3 is used, addressing corresponding thereto is repeated. Therefore, the counters 442 and 443 are also octal counters.

FIG. 4A shows the waveform of the original image before the shading process. When this is shaded, a waveform as shown in FIG.

The net pattern is not limited to the example of FIG.
Alternatively, a configuration may be adopted in which a plurality of ROMs are prepared and selected.

[Effects of the Invention] As described above, according to the present invention, when an image of a shading pattern is formed within or outside a region specified by a marker in advance on an original image, the shading pattern in the specified region is used. If there is image data of the original image at each pixel, the image data is selectively output by the color image processing means. If there is no image data of the original image at each pixel in the area, the hatching means Is selected and output.

With this configuration, when the image data of the original image is present in the designated area, the original image is reproduced and formed by color only with the image data, and the image data of the original image is contained in the designated area. If there is no such data, a hatched pattern can be reproduced in color by shading data. Thereby, color reproduction can be performed on the original image so that the hatched pattern does not overlap the original image that has been marked in advance.

In this case, since the image and the halftone image do not overlap each other and are recorded, the edge portion of the original image does not become unsightly due to the halftone image.

Further, in the case of recording a color image, if the shading process is also performed in color, the color image quality of the image is degraded due to the overlap of the two. It has features such as being improved.

Therefore, the present invention is extremely suitable for application to the above-described color copying machine and the like.

[Brief description of the drawings]

FIG. 1 is a system diagram of a main part showing an example of a color image processing apparatus according to the present invention, FIG. 2 is a system diagram showing an example of a shading processing circuit which is a main part of the present invention, and FIG. FIG. 4 is a diagram showing an example of data, FIG. 4 is a waveform diagram for explaining a shading process, FIG. 5 is a schematic configuration diagram of an electrophotographic copying apparatus applicable to the present invention, and FIG. 6 is an example of a color discrimination map. 7, FIG. 7 is a truth table of a color code, FIG. 8 is a system diagram of a region extracting circuit, FIGS. 9 and 10 are explanatory diagrams for region extraction, respectively, and FIG. 11 is a shading process. FIG. 1 Enlargement / reduction processing means 35 Color discriminating circuit 70 Output device 300 Color ghost correction means 450 Filtering correction means 420 Extraction processing means 440 Shading means 460 Inversion Means 500: Area extraction means 600A: Multi-value conversion means 600B: Automatic threshold setting means 800: Attribute detection circuit

Claims (1)

(57) [Claims] 1. A color image processing apparatus configured to form a shading pattern on an original image within or outside a region designated by a marker in advance, after color-separating the image data based on the original image, Color image processing means for color-separating into a plurality of colors and at least color image processing of the original image, and area extraction means for extracting the inside or outside of the specified area from the original image by the color image processing means, Shading means for outputting shading data for forming the shading pattern in the area extracted by the area extracting means; and for each pixel in the area extracted by the area extracting means, If there is image data, the image data is selectively output by the color image processing means, and each image data in the area extracted by the area extracting means is output. A selection circuit for selecting and outputting hatched data by the hatching means when there is no image data of the original image in the pixel.