JPH0797820B2 - Color image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention allows the inside and outside of a specific area designated by a color marker to be
For example, the present invention relates to a color image processing apparatus capable of recording in a specific color, and particularly to a color image processing apparatus suitable for application to a simple electrophotographic color copying machine having an improved detection operation of a designated area.

BACKGROUND OF THE INVENTION Color image information such as an original 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 copying machine is used. A color image processing apparatus adapted to record on a recording paper is disclosed in Japanese Patent Laid-Open No.
-147374, JP-A-58-62769 and the like.

FIG. 32 shows a main part of a configuration showing an example thereof.

In the figure, the color image information is color-separated into white and cyan, and each of them is projected on the image sensors 104 and 105 such as CCD and photoelectrically converted.

The white and cyan color signals are supplied to the subtractor 2, from which the red signal is color-separated, and these color signals are respectively AGC.
After the gain is adjusted by the circuits 3, 4, and 5, the image processing circuit 10 performs image processing such as gamma correction. afterwards,
It is binarized in the binarization circuits 6, 7, 8.

The binarized output is re-converted into red and black color signals by the arithmetic circuit 9, and is supplied as an image signal to the color copying machine to reproduce a color image.

FIG. 33 shows an example in which the image processing and the binarization processing are reversed.

[Problems to be Solved by the Invention] By the way, in such a color image processing apparatus, an area marked on an original using a specific color marker is
You may want to record with this specific color.

For example, as shown in FIG. 34, when a part of a black-and-white document is marked with a specific color, such as red or blue, the color of the image information inside this color marker, that is, black, is the color of the color marker, red. This is the case when recording in blue or blue.

In order to perform such partial color conversion processing, it is necessary to use binarized color data and detect a closed area surrounded by color markers.

Further, a circuit for processing color information for each color of YMC is required like the conventional image processing apparatus, which is complicated and large-scale.

The present invention considers such points, simplifies the circuit,
An object of the present invention is to provide a color image processing device that reduces the circuit scale and detects a designated area.

[Means for Solving Problems] The above problem is that the original color image signal of the color image in which the specific area portion is designated by the color marker is processed, and the one corresponding to one pixel is processed as the color data and the density data. A first image processing means for generating a color image signal each of which is composed of a plurality of bits, and the color data is processed to independently detect a color area for each color marker, and an overlapping area Is a second image processing means for determining a color area by calculation, and a third image processing means for performing image processing based on the color area detected or determined by the second image processing means to generate an image reproduction signal. And a color image processing device characterized by having:

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

For convenience of description, the color image processing apparatus according to the present invention will be described in detail with reference to FIG.

The color image information (optical image) of the original 52 is separated into two color separated images by the dichroic mirror 55. In this example, the color separation image of red R and the color separation image of cyan Cy are separated. Therefore, the cutoff of the dichroic mirror 55 is
Those with a wavelength of 540-600 nm are used. As a result, the red component becomes transmitted light and the cyan component becomes reflected light.

The color-separated images of red R and cyan Cy are supplied to image reading means such as CCDs 104 and 105, and the image signals of only the red component R and cyan component Cy are output from each.

The image signals R and Cy are supplied to the A / D converters 60 and 61 to be converted into digital signals of a predetermined number of bits, 6 bits in this example. Shading correction is performed at the same time as A / D conversion. Reference numerals 15A and 15B denote shading correction circuits.

Gate circuit for shading-corrected digital image signals
In 30, 31, only the signal of the maximum document size width is extracted and supplied to the color separation circuit 35 in 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 the color separation circuit 35.
And is separated into a plurality of color signals, and simultaneously gamma-corrected.

In this example, the case where the color signals are configured to be separated into three color signals of red, blue, and black is illustrated, and thus gamma correction is also performed on each of the color signals.

Each of the separated color signals is color data (also called color code data; 2-bit data) indicating the color information.
And its density data (6 bit data).

Gamma-corrected data of each color signal is, for example,
The one stored in the color separation map of the ROM configuration can be used.

The color-separated image data moves to a color image processing step.

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

This is because undesired color ghosts (color ghosts) are generated particularly in the vicinity of black characters during color separation. Depending on the configuration of the color separation map, red or blue color appears around the black character at its edge. Image quality is improved by removing color ghosts. The color ghost processing is applicable only to color code data.

Image processing includes resolution correction, partial color conversion processing, and threshold value correction for multi-valued conversion, in addition to color ghost correction.

450 is a resolution correction means. Since the resolution correction is contour correction, the target image data for processing is density data.

The partial color conversion process is an image process for recording a closed area designated by a specific color with the specific color.

Color markers such as red and blue are used to specify the closed region.

The means 500 for realizing the partial color conversion processing is an area extraction circuit 500A for detecting an original image area marked by a color marker on an original or the like, and color data for copying the extracted area in a specified color. It is composed of a selection circuit 500B. Of course, it is also possible to record the outside of the designated area in the designated color.

The area extraction circuit 500A outputs a signal (area signal) indicating the area surrounded by the color markers, and this and the color code data are supplied to the color data selection circuit 500B.

The color data selection circuit 500B is input with a BBR signal or the like indicating a color that should be currently imaged and output, and the density data whose resolution is corrected from these and the input signal described above is used as the multi-value quantization means 600 in the next stage. It is selected whether or not to send to the.

When partially performing color conversion, the black information in the area surrounded by the color marker is recorded in the color of the marker. For example, the black information in the area surrounded by the red marker is controlled to be output in the copy sequence for recording red,
The area is recorded with the specified color.

As described above, in the present invention, the detection operation of the designated area and the color recording operation are performed in synchronization with each other.

Therefore, such partial color conversion processing, in other words, the color designation processing in the closed area, is performed when color development is performed by rotating the drum for each color and developing the final color. It becomes possible for the first time by adopting a developing system that performs a fixing process.

The image capturing operation is performed multiple times for each color. in this way,
The image recording process can be performed in real time by performing the imaging operation and the developing operation a plurality of times. Real-time processing can reduce the memory for image storage.

The image data (density data) output from the color data selection circuit 500B is multivalued by the multivalue conversion means 600. In this example, 6-bit density data is converted into 1,0 1-bit data (binary data). Threshold data (6 bits) that is a reference for binarization is set manually or automatically.

Therefore, the threshold selection means 600A is composed of a threshold determination means 630 for manual setting and a threshold determination means 610 for automatic setting. The manual threshold value determining unit 630 is configured to be able to independently determine the threshold value for each color, and the threshold value specified externally is output, and the threshold value is binarized.

The automatic threshold value determining means 630 is composed of a ROM that stores a predetermined threshold value. Manual or automatic switching is performed by the EE release signal. Normally, it is the automatic setting mode (EE mode). Also. A BBR signal is supplied which indicates in which sequence the developing device is under development processing.

The image data binarized by the binarization circuit 600B is supplied to the output device 700 via the interface circuit 40. The interface circuit 40 has a first interface and a second interface, one of which is for receiving patch image data or the like used for controlling the toner density.

A laser recording device or the like can be used as the output device 700. In the case of using the laser recording device, the binarized image is converted into a predetermined optical signal, and this is based on the binary data. Is modulated.

An electrophotographic color copying machine is used as the developing device. In this example, two-component non-contact jumping development and reversal development are adopted. 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 the OPC photosensitive drum for image formation by three rotations of the drum, and after the development, transfer is performed once. It is designed to be transferred to recording paper such as paper.

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

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

A simple color copying machine attempts to record a color image by separating color information into about three types of color information. In this example, black BK, red R, and blue B are exemplified as the three types of color information to be separated.

By turning on the copy button of the apparatus, the document reading section A
Is driven.

First, the original 82 on the original table 81 is optically scanned by the optical system.

This optical system is composed of a carriage 84 provided with fluorescent lamps 85 and 86 and a reflection mirror 87, and a movable mirror unit 88 provided with V mirrors 89 and 89 '.

The carriage 84 and the movable unit 88 are made to travel on the slide rail 83 at a predetermined speed and direction by a stepping motor 90.

Optical information (image information) obtained by illuminating the original 82 by the fluorescent lamps 85 and 86 is guided to the optical information conversion unit 100 via the reflection mirror 87 and the V mirrors 89 and 89 '.

When scanning a color document, commercially available warm white fluorescent lamps are used as the fluorescent lamps 85 and 86 to prevent the emphasis or attenuation of specific colors based on optics. These fluorescent lamps 85 and 86 are lit and driven by a high frequency power supply of about 40 kHz. Also, in order to keep the tube wall at a constant temperature or promote warm-up, it is kept warm by a heater using a posistor.

A standard white plate 97 is provided on the rear surface of the platen glass 81 at the left end. This is because the image signal is normalized to a white signal by optically scanning the standard white plate 97.

The optical information conversion unit 100 includes a lens 101, a prism 102,
It is composed of a dichroic mirror 103, a CCD 104 that projects a red color separation image, and a CCD 105 that projects a cyan color separation image.

Optical signals obtained from the optical system are aggregated by the lens 101, and color-separated into red optical information and cyan optical information by the dichroic mirror provided in the prism 102 described above.

By forming each color separation image on the light receiving surface of each CCD, an image signal converted into an electric signal is obtained. The image signal is processed by the signal processing system, and then each color signal is output to the writing unit B.

As shown in FIG. 1, the signal processing system includes signal processing circuits such as A / D conversion means, color separation means, and binarization means.

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

When the deflection scanning is started, the beam scanning is detected by a laser beam index sensor (not shown),
Beam modulation by the first color signal (for example, a blue signal) is started. The modulated beam is made to scan the image forming body (photosensitive drum) 11 to which uniform charging is applied by the charger 121.

Here, an electrostatic image corresponding to the first color signal is formed on the image forming body 11 by the main scanning by the laser beam and the sub-scanning by the rotation of the image forming body 11.

This electrostatic image is developed by the 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 the development.

The blue toner image is rotated with the cleaning blade 127 being released from the pressure contact, and an electrostatic image is formed on the basis of the second color signal (for example, a red signal) in the same manner as in the case of the first color signal. Is developed to form a red toner image.

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

Therefore, the multicolor toner image is written on the image forming body 11.

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.

The recording paper P fed from the paper feeding device 141 via the feeding roll 142 and the timing roll 143 is conveyed onto the surface of the image forming body 11 in a state of being synchronized with the rotation of the image forming body 11. . Then, the multi-color toner image is transferred onto the recording paper P by the transfer pole 130 to which a high voltage is applied from the high voltage power source, and separated by the separation pole 131.

The separated recording paper P is conveyed to the fixing device 132 to be subjected to a fixing process and a color image is obtained.

The image forming body 11 that has completed 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 the collection of the toner cleaned by the blade 127, the blade 12
A predetermined DC voltage is applied to the metal roll 128 provided on the 7. The metal roll 128 is arranged in a non-contact state with the surface of the image forming body 11.

The blade 127 is released from the pressure contact after the cleaning is completed.
Further, an auxiliary cleaning roller 129 is provided, and by rotating and pressing the roller 129 in the direction opposite to the image forming body 11, unnecessary toner is sufficiently cleaned and removed.

The sheet feeding device 141 is provided with a sensor 65a, and its detection output is
It is sent to the CPU.

The configuration of each part in FIG. 1 will be described in order.

First, color separation (a plurality of bits of image data) for separating a plurality of color signals from the shading-corrected red and cyan output signals is executed. At the same time, gamma correction is performed. The color signals to be separated are three colors of black, red and blue.

If a method of binarizing an image signal and then color-separating the image is adopted as in the conventional example, the data after the color separation is a binarized signal, which is inappropriate in view of performing various kinds of processing.

Here, the colors are separated before being binarized. A map as shown in FIG. 5 is prepared for color separation. The color separation map is ROM (bipolar ROM). In this case, the color code (specify red, blue, black) at the address destination given by the 6-bit image data VR and VC having the halftone level.
And the density information after gamma correction are stored. That is, 1 image information = color code + density information.

For example, a pixel with hexadecimal display and a density value of 30 levels (XX011110) is Similarly, blue = 01011110 = 5E black = 00011110 = 1E white = 11011110 = DE For white, either DE or CO may be used. In other words, the white density information is not useful.

The above data is stored at each address as shown in FIG. Here, the color code is 4 bits including red, blue, and black including white, so that it is set to 2 bits, but it is clear that if the number of colors increases, the number of bits may be increased accordingly. Further, the density information is also 6 bits here, but it is practically sufficient to use 4 bits only for characters. Therefore, it is clear that the number of bits may be changed depending on the target image.

The boundary of color separation as shown in FIG. 5 needs to be determined in consideration of the output fluctuation at the edge portion of the line portion. Otherwise, an unnecessary color called a color ghost, which is a kind of color error, will occur at the edge of a black character or the like.

On the other hand, in practice you want to extract a specific color, or red,
This is the case when you want to extract colors other than blue and black. For these, a color separation map different from this example is prepared, and one is selected from a plurality of color separation maps in accordance with a request. Alternatively, the color separation ROM can be attached and removed,
The required ROM (actually a ROM pack) may be replaced.

Maps for three colors are shown in FIGS. 6A and 6B, and maps for four colors are shown in FIG. 6C. These map data are also the data after gamma correction.

An example of the gamma correction curve is shown in FIG. Curve L2 is γ <1
The curve L3 is an example of γ> 1.

FIG. 2 shows a specific example of the color separation circuit 35. As shown in FIG. 3, when the three correction curves L1 to L3 including uncorrected (γ = 1) are properly used, three color separation ROMs 36A to 36C are prepared.

The same color code data and the density data after gamma correction according to each correction curve are stored in each.

Which gamma correction curve is used is selected by the selection signal supplied to the terminal 37.

When the capacity of the color separation ROM is large, each data of the color separation ROMs 36A to 36C described above can be stored in a single ROM.

FIG. 4 shows another example of the color separation circuit 35.

In this example, a dedicated ROM 39B for gamma correction in which the gamma correction data itself shown in FIG. 3 is stored is prepared.

Color code data as shown in FIG. 5 and density data before gamma correction are stored in the color separation ROM 39A, color code data and density data are read out when necessary, and the density data is stored in the gamma correction ROM 39B. In the, the predetermined gamma characteristic is added, the gamma-corrected density data,
The color code data is written in the RAM 38.

Color separated and shading corrected image signals VR and V
C is supplied as the address data of the RAM 38, and the color code data and the density data determined by the address are read out.

The read density data is already in ROM3 for gamma correction.
Since it is gamma-corrected in 9B, the image signal after gamma correction can be immediately obtained by directly accessing the data stored in the RAM 38.

Thus, when using the RAM 38, high speed access is possible.

The gamma correction ROM 39B stores density data for giving gamma characteristics as shown in FIG. 3, and the necessary gamma characteristics are selected and given by a selection signal from the terminal 37.

Address data for writing and reading to and from the ROM 39A and the RAM 38 is generated by the address generation circuit 34.

Next, a color ghost correction means 30 for removing a color ghost from the image data color-separated as described above.
0 will be described.

An example of appearance of a color ghost is shown in FIG.

This figure shows a color ghost that appears after color separation by capturing an image of a black character "sex". As can be seen from this example, as the color ghost, as shown in FIGS. 8A to 8C, red and blue are present at the edge portion of the black line,
Black appears at the edge of the blue line and black appears at the edge of the red line.

Obviously, the appearance of color ghosts is different in other color combinations.

Color ghost removal is based on the color pattern method.

This is because, as with the original black-> red, blue ghost, the original red, blue-> black ghost, the color ghost color that appears is determined with respect to the original color. In the case of the color pattern method, the color of the original image can be identified by determining the color appearance (pattern) of the pixel of interest and the pixels around it in order to determine the color of the pixel of interest.

As an example, FIG. 9 shows determination of the pixel of interest, the surrounding color pattern, and the color of the pixel of interest determined at that time.

In the first example, since both sides of the pixel of interest are white and black, the blue color of the pixel of interest is determined to be a color ghost that appears at the black edge. Red in the third example is also determined to be a black color ghost. Therefore, in both the first and third examples, the pixel of interest is changed to black.

On the other hand, in the second and fourth examples, it is not determined that the color ghost appears, and the color of the pixel of interest is output as it is.

Such processing is difficult to realize with an arithmetic circuit, and in this example, it is ROMized and used in a LUT (look-up table) format. As the color pattern, a one-dimensional or two-dimensional method can be considered, but if the number of colors is N and the number of peripheral pixels including the pixel of interest is M, the size of the color pattern is N ^M.

Therefore, if a two-dimensional pattern is used, the number of M will suddenly increase and it will not be practical. That is, in the case of a two-dimensional pattern, the number of peripheral pixels in each dimension (main scanning direction / sub scanning direction) cannot be large, but only the number of patterns is large. Figure 10 shows the relationship between the size and the number of color patterns.

When a 1 × 7 size color pattern is used, the color code is input as the ROM address. For example, in the color pattern below The color code pattern is white: white: blue: blue: black: black: black 11: 11: 01: 01: 00: 00: 00 and the address is 3D40. The black code 00 is stored in. The LUT is executed by the above method.

Actually, a 1 × 7 pattern requires a 14-bit address line, and a bipolar ROM with an address 14-bit input and a color code 2-bit output is all that is needed, but this is a large-capacity high-speed ROM. Is rarely on the market and is expensive.

In the embodiment, the ROM is selected by the first pixel and the LUT is performed by the codes of the remaining 6 pixels. In other words, this is a mode in which two ROMs are used. The first ROM has black and blue heads, and the second ROM has red and white heads.

First ROM (Black, Blue ROM) Start code Black (00), Blue (01) Address Contents 00000000000000 (Black Black Black Black Black Black Black Black) :: :: 00111111111111 (Black White White White White White White) 01000000000000 (Blue Black Black Black Black Black Black: Black ::::: 01111111111111 (blue white white white white white white) Second ROM (black, blue ROM) Start code Red (10), white (11) Address content 10000000000000 (red black black black black black black black) ::::: 10111111111111 (red white white white white white white) 11000000000000 (black and white black black black black black black) :: :: :: 11111111111111 (white white white white white white white white) In the color pattern shown in FIG.
ROM is selected.

FIG. 11 shows an example of the color ghost correction means 300. The color ghost process is performed in the main scanning direction (horizontal scanning direction) and the sub-scanning direction (vertical scanning direction).

In this example, the image data of 7 pixels in the horizontal direction and 7 lines in the vertical direction is used to remove the ghost in the horizontal and vertical directions.

Only the color code of the image data is targeted for the color ghost processing.

Therefore, the color code read from the color separation ROM is first supplied to the ghost correction circuit 300A in the output scanning direction. Therefore, the color code data is sequentially supplied to the 7-bit shift register 301 and parallelized. The parallel color code data for 7 pixels is supplied to the ghost removing ROM 302 in the horizontal direction, and ghost removing processing is performed for each pixel. The usage example of the ROM 302 is as described above. When the ghost processing is completed, it is latched by the latch circuit 303.

On the other hand, the density data output from the color separation ROM is supplied to the latch circuit 306 via the shift register 305 (7-bit configuration) for timing adjustment, and the density data is serially transferred following the color code data. The data transfer conditions are determined so that

The serially processed color code data and density data are supplied to the line memory unit 310 provided in the color ghost correction circuit 300B.

The line memory unit 310 is provided to remove the color ghost in the vertical direction by using the image data of 7 lines. The line memory is used for a total of eight lines, but this shows one means of real-time processing, and of course, real-time processing is possible even for seven lines.

The color code data and the density data for eight lines are separated in the gate circuit group 320 in the subsequent stage. The gate circuit group 320 is provided with gate circuits 321 to 328 corresponding to the line memories 311 to 318, respectively.

The output data of the 8-line memory synchronized in the line memory unit 310 is separated into the color code data and the density data in the gate circuit group 320, and the separated color code data is supplied to the selection circuit 330 for a total of 8 lines. The color code data of the seven line memories required for the color ghost processing is selected from the line memory. In this case, when the line memories 311 to 317 are selected,
At the next processing timing, the selected line memories are sequentially shifted as the line memories 312 to 318 are selected.

The selected and synchronized 7-line memory worth of color code data is stored in the next vertical ghost removal ROM 340.
To remove vertical color ghosts.

Then, it is latched by the latch circuit 341.

On the other hand, the density data separated by the gate circuit group 320 is directly supplied to the latch circuit 342, and timing-adjusted with the color code data before being output.

Resolution correction (MTF correction) is processed after color separation.

Conventionally, as described above, the processing step of performing color separation after binarizing the image data is generally performed, so that the resolution correction needs to be executed in a stage before the binarization processing. Therefore, in the case of capturing a color separation image of a document using a plurality of CCDs, resolution correction must be executed in correspondence with each CCD output. That is, it is necessary to prepare a plurality of circuits for resolution.

Moreover, since the MTF of the optical lens is different for each of the plurality of color separations, there is also a disadvantage that the parameters for MTF correction are different for each resolution correction circuit.

If resolution correction processing is performed after color separation and before multi-value quantization processing as in the embodiment, since only one piece of information is handled, the circuit scale is reduced and the determination of correction parameters is simplified. You will have the above advantages.

Next, the partial color conversion process will be described.

The partial color conversion process is a type of editing process that allows an image (black image) inside or outside an arbitrary area designated by a color marker to be copied in the color of the marker.

Conventionally, the position is designated by a digitizer or the like, then the original image is placed, the scanning process is started, and the position data input switch is operated each time the position is designated. Further, the position designation is a rectangular shape such as a square or a rectangle, and an arbitrary area cannot be designated.

In the partial color conversion process described below, an arbitrary area written with a marker can be copied in the color of the marker. For example, if the area a is designated with a blue marker as shown in FIG. The area a is automatically detected, and the image included in the area a is copied in the marker color blue.
The area outside the area a is a normal black and white copy. A red marker may be used as the color marker. The original that is the target of partial color conversion is a black and white original.

The order of detecting the designated area is matched with the order of color recording as described above. In the above description, since the colors are recorded in the order of blue, red, and black, the color markers are also detected in the order of blue and red.

Now, in order to copy the image in the specified area a with the specified color, the marker signals BP and RP (actually color code data) indicating the area of the color marker and the area a are copied as shown in FIG. It is necessary to detect the indicated area signals QB 'and QR', respectively.

Therefore, as shown in FIG. 1, a color data selection circuit 500B is provided in addition to the area extraction circuit 500A. The color data selection circuit 500B is used to select the density data of the development color corresponding to the copy sequence (developing sequence) when the partial color is specified, and the density data of the development color corresponding to the copy sequence during the normal copy. Circuit.

FIG. 14 is a specific example thereof, and each bit data of the color code data obtained by scanning the color marker is supplied to the color marker detection circuit 501 to detect the presence / absence of a specific color marker. In the embodiment, the two marker signals BP and RP are detected because it is applied to two types of red and blue markers.

The marker signals RP and BP are supplied to the preprocessing circuits 502 and 503, respectively, and are preprocessed so that the marker signals are faithful to the designated area. The pre-processing is a kind of signal waveform shaping processing, and in the embodiment, pre-processing circuits 502 and 503 are used in blur correction circuits 504 and 507, noise correction circuits 505 and 508 (both in the main scanning direction) and marker out correction circuits 506 and 509 in the sub scanning direction. Is configured. The blur correction of the color marker is 16dots / mm
The blurring within 8 dots / mm is corrected and the noise correction within 8 dots / mm is corrected.

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

More specific configurations of these will be described below.

FIG. 15 shows an example of the color marker detection circuit 501. By scanning the color marker, the color of the marker itself can be detected.

The blue color code data is “01” and the red color code data is “10”.

Therefore, as shown in the figure, the high-order bit data itself and its phase-inverted data by the inverter 511 are supplied to one NAND circuit 513.

Similarly, the lower bit and the phase inversion of the lower bit by the inverter 512 are supplied to the other NAND circuit 514. Then, the AND outputs of the vertical effective area signal V-VALID and the size signal B4 are supplied to the NAND circuits 513 and 514 as gate signals. Reference numeral 515 represents an AND circuit.

As a result, when the color marker is blue, the blue marker signal BP having the pulse width corresponding to the thickness of the contour of the marker is
Is output from the terminal 516.

Similarly, when the color marker is red, the red marker signal RP is output to the other terminal 517. An example of the marker signal is shown in FIG.

FIG. 16 shows an example of the area extraction unit 520.

The area extraction unit 520 is composed of first and second area extraction units 520A and 520B, each having data storage circuits 521A and 522A and area operation circuits 521B and 522B. First and second area extraction unit 5
Both 20A and 520B have a red marker area extracting function in addition to the function of extracting the blue marker area. For convenience of explanation,
The area extraction of the blue marker will be described.

When forming the blue area signal, the area signal of the current scanning line is calculated and formed from the area signal obtained by scanning immediately before and the marker signal obtained by scanning the current scanning line.

For that purpose, it is necessary to perform arithmetic processing using a period of at least 3 lines. Therefore, the first data storage circuit
The 521A has a function of storing the area signal, which is the final data of the immediately preceding scanning line, over one line, and the first and second marker signals BP formed by scanning the area signal and the current scanning line. It is necessary to have a function of storing the area signals (actually NAND output) and a function of storing the area signals of the current scanning line obtained by arithmetically processing these area signals.

Further, in the embodiment, the second area signal is formed by reading the memory from the reverse direction, and therefore the number of memories required to realize these memory functions is
16 in total. Furthermore, since it is necessary to detect the red marker, 32 line memories are required in total.

Therefore, the first data storage circuit 521A has a pair of memories 525 and 526 each composed of eight line memories. A pair of Schmitt trigger circuits 523 and 524, a pair of data selectors 527 and 528, and a latch circuit 529 are provided to switch and use these for each line.

The first data storage circuit 521A is supplied with three signals BP, BNo, and QB 'obtained by the blue first area calculation circuit 530B and the like in addition to the blue marker signal BP as input signals.

In the first area calculation circuit 530B, the area signal QB 'of the blue marker on the current scanning line n is formed from the immediately preceding area signal QB and the marker signal BP on the current scanning line.

For convenience of explanation, consider the scan line n shown in FIG.
The relationship between the area signal QB (this is the area signal of the scanning line (n-1)) and the marker signal BP is as shown in FIGS. These signals are stored in the memory 525 line by line. In the next scanning line (n + 1), these signals are read out via the data selector 527 and the latch circuit 529 (D and E in the same figure).

The pair of signals QB and BP are supplied to the NAND circuit 531 and the NAND output PB1 (F in the figure) is supplied to the preset terminal PR of the D-type flip-flop 532 as a preset pulse, and the immediately preceding area signal QB is supplied to its clear terminal CL. Supplied. As a result, the first NAND output (first contour signal) BNo as shown in FIG.

The first NAND output BNo and the marker signal BP are sequentially stored in the memory 526.
Stored in. Therefore, in the scan line (n + 1), the Schmitt trigger circuit 524 is controlled to be in the active state.

The second region extraction unit 520B also performs the same processing operation at the same timing. However, each of the memories provided in the memory is address-controlled so that the writing is performed in the forward direction and the reading is performed in the reverse direction.

Therefore, the output timing of the marker signal BP and the immediately preceding area signal QB is W1 in the n line, but is W2 in the (n + 1) line, and the reading is performed slightly faster (H and I in the same figure). As a result, the second NAND output BN1 is
become that way. Marker signal BP and second NAND output BN1
Is again stored in the data storage circuit 521B.

In the next scan line (n + 2), the first NAND output BN
o, the marker signal BP and the second NAND output BN1 are read out (LO in the figure).

Here, as described above, the memory provided in the second area extracting unit 520B is for writing in the forward direction and reading in the reverse direction. Therefore, in this example, the first NAND output BNo and the second NAND output BN1 The read timings W3 and W4 match.

Both are supplied to the AND circuit 533, and the AND output AB and the marker signal BP (N, O in the figure) are supplied to the OR circuit 534, whereby an OR output QB 'as shown in P in the figure is obtained.

This OR output QB 'is irreversibly the signal indicating the inside of the outline of the blue marker drawn on the current scan line n. That is, this OR output becomes the area signal QB 'of the current scan line.

It can be easily understood that the area signal QB 'is fed back to the data storage circuits 521A and 521B because it is used as the immediately preceding area signal QB on the next scan line.

In this way, the marker area can be accurately detected by using the pair of NAND outputs BN0 and BN1 obtained by reversing the reading direction of the memory.

Since the detection of the red marker is exactly the same, the area calculation circuit 53
The description of 0R is omitted. However, 535 is a NAND circuit, 536 is a D-type flip-flop, 537 is an AND circuit, and 538 is an OR circuit. And QR 'shows the area | region signal of a red marker.

The Schmitt trigger circuits 523 and 524, the memories 525 and 526, and the data selectors 527 and 528 are prepared as a pair in order to consider the case where the blue marker and the red marker are present at the same time. Therefore, these are alternately used line by line by the switching signal of two line cycle supplied to the terminals A and B.

The area signals QB 'and QR' respectively obtained at the output terminals are supplied to the area determination circuit 540 shown in FIG.

The area determination circuit 540 is a control means for an area signal for recording an image as shown in FIG. 19B when a marker is specified as shown in FIG. 19A.

That is, a black and white image is recorded in sections I and V, and a section II,
In IV the black image is recorded as the red image, and the interval
In III, the gate signal S of the density data is formed from the area signals QB 'and QR' so that a black image is recorded as a blue image.

The area determination circuit 540 has four flip-flops 541 to 544, and the area signals QB 'and QR' latched by the flip-flops 541 and 542 in the preceding stage are supplied to the corresponding NAND circuits 545 to 548, and the flip-flops 543 and 544 in the subsequent stage. The region signals QB 'and QR' latched by are supplied to the corresponding NAND circuits 545 to 548. Then, the color code data CC indicating black is supplied to the respective NAND circuits 545 to 548 through the AND circuit 554. The switching circuit 553 is supplied with a BBR signal indicating which color is currently being copied.

Therefore, considering the signal relationship on the scanning line n shown in FIG. 19A, it becomes as shown in FIGS. 20 and 21.

FIG. 20 shows what kind of FF outputs Q1 and Q2 (H and L in the same figure) are obtained by inputting the region signals BP and RP (A to D in the same figure).

Further, the first NAND circuit M545 shown in FIG. 21D obtains a first NAND output M1 by the signals shown in FIGS. Similarly, the second NAND circuit 546 obtains the second NAND output M2 shown in FIG. 7G based on the input signals shown in FIGS. As a result, from the first AND circuit 551 shown in FIG.
The gate signal S1 related to the section III shown in is output.

Similarly, the third NAND output M3 of FIG. L from the input signals of J to K in the same figure and the fourth NAND output M3 of FIG.
The NAND output M4 of is obtained. As a result, the second AND circuit 552 outputs the gate signal S2 (P in the figure) related to the sections II and IV.

Then, the gate signal S3 (T in the figure) corresponding to the sections I and V is output from the fifth NAND circuit 549 in response to the input signals in Q to S in the figure.

The gate signals S1 to S3 are selected in the switching circuit 553 according to the BBR signal indicating the copy sequence. Therefore, the gate signal S1 is selected in the blue recording mode, and the gate signal S2 is selected in the red recording mode.
, And when in the black recording mode, the gate signal S3
Will be selected.

Gate signals S1 to S3 output from switching circuit 553
Is supplied to the color data selection circuit 500B shown in FIG.

First, the gate signal S and the color code data are the gate circuit.
Supplied to the 570. The gate circuit 570 is a pair of NAND circuits 57
It is composed of 1,572.

When the color code data is black, the gated signal S is gated, and one of the gated signal S and the BBR signal is selected by the selection circuit 573. Which one is selected is controlled based on the designated processed signal.

Then, the density data selection circuit 574 selects the density data corresponding to the color code data from the outputs.

In that case, white density data (always 1) is selected in a section other than the gate signal S. Therefore, for example, in the blue recording mode, the white data is always selected except the section III.
As a result, the blue image is recorded only in the section III in the blue recording mode, the red image is recorded only in the sections II and IV in the red recording mode, and the section I in the last black recording mode.
Only V and V are recorded as black images (Fig. 19B).

By providing the area determination circuit 540 as described above,
Even in the areas that are designated redundantly, the color of the inner marker has priority. The non-overlapping area will be copied with the marker color that specifies the non-overlapping area.

FIG. 23 shows an example of the copy operation when the designated area is detected. In this case, as shown in FIG. 34, a case where blue and red color markers are written on a part of a black-and-white original will be exemplified.

When the copy sequence is in the order of blue, red and black, the color markers are detected in this order.

When the copy mode starts, the blue color marker area is first detected, and when that color marker is detected, the black color code data in this detection area is converted into the blue color code data and The black of is copied in blue (steps a and b).

The copy state at that time is shown in FIG. 24A.

Next, a red color marker area is detected, and when that color marker is detected, the black color code data in this detection area is converted into red color code data, and the black in that area becomes red. Copied (steps c, d).

FIG. 24B shows the copy state at that time.

Finally, the black information in the area other than these detection areas is copied in black (step e). Therefore, finally, as shown in FIG. 6C, the inside of the color marker area is copied in that color, and the others are copied as the original.

A modification of partial color conversion is shown below.

The partial color conversion represents the detection of the designated area and the processing of the image data or the color in the designated area without any correction.Therefore, the partial area extraction, deletion, reversal, mirror image, enlargement / reduction, position movement, Any combination of these processes can be processed in the same way.

It is also possible to determine the processing content in advance for each color marker and apply the previously reserved processing to the detected area.

The background color of the original is white, but other colors may be used.

As the color marker, red-based colors (orange, pink) and blue-based colors are suitable. This is because these colors are difficult to copy in the normal copy mode.

When the color marker cannot be directly written on the manuscript, the same thing can be done by marking it on the transparent sheet.

The area may be designated by filling the necessary area as shown in FIG.

Next, as the image processing, automatic / manual density adjustment will be described. The concentration adjustment is a real-time process.

If you want to set the original density in real time,
It is conceivable to create a density histogram of the original as shown in Fig. 26, but this requires prescanning.

The contents described below exemplify the threshold value determining means 610 capable of setting the optimum document density in real time without prescanning without increasing the circuit scale. The threshold value determining means 610 is provided in association with the binarization circuit 600B.

The point is that the threshold value is determined on a line-by-line basis from the data of the maximum value DH and the minimum value DL of the density data on each scanning line. In color copy, because the copy operation is performed in the order of blue, red, and black,
The density data of the pixel corresponding to the currently recorded color is sampled, and the maximum and minimum values are calculated for each color.

An example of the calculation formula of the threshold value T for binarization is shown.

Ti = ki (DH-DL) + αi + DL where i = blue, red, black k = 0.1 to 0.8, preferably 0.2 to 0.6 α = correction value k and α are different for each color. However, it is obvious that the difference also depends on the value of the density data stored in the color separation map described above.

For example, k is 1/2 to 1/3 for black and about 1/2 for red and blue. α is about −10 for black and about 2 to 6 for red and blue.

Noise may be mixed in the process of calculating the maximum or minimum value, but as a countermeasure in such a case, when the concentration data changes suddenly, the previous concentration data is used as it is without sampling, Alternatively, it is possible to use the average value of the density data before and after. Further, in order to avoid a sudden change in the calculated threshold value, the average value of the threshold values of a plurality of lines that have already been determined may be used as the threshold value of the current line.

Also in the case of multi-valued conversion, it will be apparent that the coefficients k and α may be selected corresponding to each threshold value.

When the original image is copied in a single color, the coefficients k and α are different for each color. That is, there are mainly black characters in the original image, and color characters and the like exist less frequently than this. Therefore, if the threshold value is determined in accordance with the black character, the color character in the reproduced image will be skipped for red or blue. When matched with color letters, black letters tend to be crushed.

In order to prevent this, first, in the case where there is no automatic threshold value determining means 610, the threshold value is manually set independently for each color,
When binarizing, the color code of each pixel is used to address the threshold for each color.

When the threshold value determining means 610 is provided, the arrangement of the density data in the color separation ROM may be changed so that other colors can be reproduced better with the threshold value selected when copying with the designated color.

A concrete example of the automatic threshold value determining means 610 will be described below.

The example of FIG. 27 is a case in which a ROM in which a threshold value is stored for each color obtained by the threshold value calculation formula described above is prepared and the threshold value data is selected from the maximum and minimum values of the line.

In the figure, 611 indicates a ROM in which such a threshold value is stored for each color. The density data is simultaneously supplied to the maximum value calculation circuit 612 and the minimum value calculation circuit 616.

Since these are the same in content, the maximum value calculation circuit 612
The configuration of will be described.

The density data of the current pixel and the density data of one pixel before latched by the latch circuit 614 are supplied to the switching circuit 613. Then, the density data of the current pixel and the density data of one pixel before are supplied to the comparator 615 for comparing the magnitude and the levels are compared, and the comparison output indicates which of the density data of the current pixel and the one pixel before. Is selected. When the density data of the original pixel is larger, the density data of the current pixel is selected by the comparison output as shown in the figure.

Such a magnitude comparison operation is executed for all the pixels in the line to detect the maximum value DH of the line.

Similarly, also in the minimum value calculation circuit 616, the comparator 619
The minimum value of the line in the comparison output showing the minimum value obtained in
DL is detected.

Maximum and minimum values D obtained at the end of one line
The threshold ROM 611 is addressed by H and DL. It is supplied to this threshold ROM 611 which color threshold is selected.
Determined by BBR signal.

Now, the threshold selection signal from the operation / display unit is converted into the binarization circuit 60.
It is supplied to 0B and either the threshold value in the EE mode or the threshold value in the manual mode is selected. Normally set to EE mode,
When this EE mode is released by the operation switch,
The BBR signal and the level designation signal designated by the operation / display unit designate the address of the threshold ROM 630, which is a manual threshold value determination unit, and output a predetermined threshold value for binarization.

When binarizing a photographic image, use the threshold ROM630
For example, prepare an 8x8 dither matrix and set the threshold ROM6.
For address control of 30, a counter output designating a row and a column may be used. The image data may be ternarized so that gray can be expressed.

The binarized image signal is supplied to the output device 700 via the interface circuit 40. Next, the configuration and operation of the interface circuit 40 will be described with reference to FIG.

The interface circuit 40 is composed of a first interface 41 for receiving binary data and a second interface 42 for receiving the binary data transmitted from the first interface 41.

The first interface 41 is supplied with horizontal and vertical effective range signals H-VALID and V-VALID from the timing circuit 43, and is also supplied with a clock of a predetermined frequency (6 MHz in this example) from the counter clock circuit 44. It

As a result, only when the horizontal and vertical effective range signals are generated, the second binary data is synchronized with the CCD drive clock.
Will be sent to the interface 42 of.

The counter clock circuit 44 generates a main scanning side timing clock synchronized with the optical index signal.

The second interface 42 is the first interface 41.
This is an interface for selecting the binary data and the other image data that have been sent out and sending them to the output device 700 side.

The other image data is the following image data.

First, the test pattern image data obtained from the test pattern generation circuit 46, secondly, the patch image data obtained from the patch circuit 47, and thirdly, the control data obtained from the printer control circuit 45. .

The test pattern image data is used during inspection of image processing, and the patch image data for toner density detection is used during patch processing.

Each of the test pattern generating circuit 46 and the patch circuit 47 is driven based on the clock of the counter clock circuit 44, so that the timing with the binary data sent from the first interface 41 is adjusted.

The binary data output from the second interface 42 is used by the output device 700 as a laser beam modulation signal.

FIG. 29 shows a peripheral circuit of the output device 700. The semiconductor laser 931 is provided with its drive circuit 932, and the above-mentioned binary data is supplied to this drive circuit 932 as a modulation signal. The laser beam is internally modulated. The laser drive circuit 932 is controlled by a control signal from the timing circuit 933 so that it is driven only in the horizontal and vertical effective area sections. Further, a signal indicating the light quantity of the laser beam is fed back to the laser drive circuit 932, and the driving of the laser is controlled so that the light quantity of the beam becomes constant.

The operation start point of the laser beam deflected by the octahedron polygon 935 is detected by the index sensor 936, and this index signal is converted into a voltage signal by the I / V amplifier 937. This index signal is then converted into a counter clock circuit. The signal is supplied to 44 and the like, the line signal SH is formed, and the timing of the optical main scanning is adjusted.

Reference numeral 934 is a polygon motor drive circuit, and ON / OFF signals thereof are supplied from a timing circuit 933.

The image exposure means shown in FIG. 30 is a case where a laser beam scanner (optical scanning device) is used.

The laser beam scanner 940 includes a laser 931 such as a semiconductor laser, and the laser 931 is on / off controlled based on a color separation image (for example, binary data). The laser beam emitted from the laser 931 is incident on a polygon 935 composed of an octahedral rotating polygon mirror via mirrors 942 and 943. The laser beam is deflected by this polygon 935, and this is irradiated onto the surface of the image forming body 11 through the f-θ lens 944 for image formation.

945 and 946 are cylindrical lenses for tilt angle correction.

The polygonal beam 935 causes the laser beam to scan the surface of the image forming body 11 at a constant speed in a predetermined direction a, and by such scanning, image exposure corresponding to a color separation image is performed.

The f-θ lens 944 is used to make the beam diameter on the image forming body 11 a predetermined diameter.

As the polygon 935, a galvano mirror, a quartz crystal deflector, or the like can be used instead of the rotary polygon mirror.

EFFECTS OF THE INVENTION As described above, according to the present invention, a circuit for processing color information for each color of YMC is required like the conventional image processing apparatus, which is complicated and large-scale. , The original color image signal is separated into the color data and the density data, and the color data is processed to detect the color region, so that the circuit can be simplified and the circuit scale can be reduced, and each color marker can be independently processed. Since the color area is detected and the overlapping area determines the color area by calculation, there is a practical advantage that the area can be surely detected even when the area is designated by, for example, a double circle.

[Brief description of drawings]

FIG. 1 is a block diagram of the entire apparatus used for a schematic description of a color image processing apparatus according to the present invention, FIGS. 2 and 4 are system diagrams of essential parts showing a concrete example of a color separation circuit, and FIG. FIGS. 5 and 6 are views showing examples of color separation maps respectively, FIGS. 7 and 8 are illustrations of color ghosts respectively, and FIGS. 9 and 10 are color ghost corrections. 11 is a system diagram of the color ghost correction means,
12 and 13 are explanatory views of partial color conversion, respectively, FIG. 14 is a system diagram of a region extraction circuit, FIG. 15 is a system diagram of a color marker detection circuit, FIG. 16 is a system diagram of a region extraction unit, FIG. 17 is a waveform diagram for explaining the operation, FIG. 18 is a system diagram of the area determination circuit,
19 to 21 and 25 are explanatory diagrams of the operation thereof, FIG. 22 is a system diagram of a data selection circuit, FIG. 23 is a flowchart showing an example of a copy sequence, and FIG. 24 is a recorded image used for the explanation. Figure, Figure 26 is a characteristic diagram of the density histogram,
FIG. 27 is a system diagram of the automatic threshold value determining means, FIG. 28 is a system diagram of the interface circuit, FIG. 29 is a configuration diagram of the output device, and 30.
FIG. 31 is a configuration diagram of a laser beam scanner. FIG. 31 is a configuration diagram of a main part showing an example of a color copying machine applicable to the present invention.
FIG. 32 and FIG. 33 are system diagrams of conventional devices, respectively, and FIG. 34 is an explanatory diagram of color markers. 15A, 15B …… Shading correction circuit 35 …… Color separation circuit 40 …… Interface circuit 60,61 …… A / D converter 300 …… Color ghost correction means 450 …… Resolution correction means 500 …… Partial color conversion means 500A ...... Region extraction circuit 500B …… Data selection circuit 600 …… Multi-value conversion means 600A …… Threshold selection means 600B …… Binarization circuit 700 …… Output device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Yamamoto Inventor Hiroyuki Yamamoto 2970 Ishikawa-cho, Hachioji-shi, Tokyo Within Konishi Rokusha Shin Kogyo Co., Ltd. Incorporated (72) Inventor Tetsuo Kimoto 2970 Ishikawa-cho, Hachioji-shi, Tokyo Inside Konishi Rokusha Shin Kogyo Co., Ltd. (56) Reference JP 59-163980 (JP, A) JP 57-202176 ( JP, A)

Claims (1)

[Claims] 1. An original color image signal of a color image in which a specific area portion is designated by a color marker is processed to separate one corresponding to one pixel into color data and density data, each of which is composed of a plurality of bits. For generating a color image signal to be reproduced
An image processing unit, a second image processing unit that processes the color data to independently detect a color region for each color marker, and determines a color region for an overlapping region by calculation; and the second image processing unit. And a third image processing unit that performs image processing based on the color region detected or determined by the above and generates an image reproduction signal.