JP3079630B2 - Image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing system of a color image processing apparatus capable of inputting and outputting image data to and from another system without considering characteristics inherent to the apparatus.

[0002]

2. Description of the Related Art A digital copying machine reads an original II.
It is composed of a T (image input terminal), an IPS (image processing system) for processing read image data, and an IOT (image output terminal) for driving a laser printer and outputting a copy based on the image data. In the IIT, the image information of the original is extracted as an analog electric signal corresponding to the reflectance using a CCD sensor.
This is converted into multi-tone digital image data. In the IPS, various corrections, conversions, edits, and the like are performed by processing image data obtained by the IIT.
In the OT, the halftone image is output by turning on / off the laser of the laser printer based on the image data processed by the IPS.

In such a digital copying machine, multi-tone image data is subjected to IPS processing in accordance with its type. For example, in the case of a character or the like, a sharp image with edge emphasis is converted to a half-tone image such as a photograph. In this case, it is possible to output a smooth image smoothed by removing moiré and halftone dots, and a highly reproducible color image with adjusted vividness. Images that have undergone color conversion, trimming, shifting, combining, reducing, enlarging, and other editing can be output. In response to this IPS, IIT
The original is read with signals separated into three primary colors R (red), G (green), and B (blue), and image data is output. In the IOT, Y (yellow), M (magenta), and C (cyan) are output. ,
A color digital copying machine is constructed by forming a dot image of each color material of K (black) and superimposing and outputting them. Therefore, in such a color image processing apparatus such as a color digital copying machine or the like, using the developing device for each color material, scanning is repeated four times in accordance with the development process of each color material to read the original and read the full-color image data. Processing is in progress.

Next, the present applicant has proposed an outline of the above-mentioned color digital copying machine (for example, Japanese Patent Laid-Open No. 22327/1990).
No. 5) will be described as an example. FIG. 5 is a diagram showing a configuration example of a conventional color digital copying machine.

[0005] In FIG. 5, an IIT 100 separates color originals into three primary colors B, G, and R using a CCD line sensor, reads a color original, and converts the original into digital image data. Exposure and development with a laser beam to reproduce a color image. Then, an END conversion (Equivalent Neutral Density: equivalent neutral density conversion) circuit 101 between the IIT 100 and the IOT 115 is output from the IOT interface 1.
Reference numeral 10 denotes an image data editing system (IPS; image processing system) which converts B, G, and R image data into Y, M, C, and K color materials, and performs a development cycle. Each time a color material signal corresponding to the developed color is
15 is output.

In the IIT 100, one pixel is used for each of B, G, and R using a CCD sensor.
Read at a size of 6 dots / mm and read the data
It is output in bits (3 colors × 8 bits; 256 gradations). The CCD sensor has B, G, and R filters mounted on the top surface, and has a density of 16 dots / mm and a size of 300 mm.
And scans at 16 lines / mm at a process speed of 190.5 mm / sec, so that read data is output at a rate of 15 M pixels per second for each color. And, in IIT100, B, G, R
By log conversion of the analog data of the pixel of
The reflectance information is converted into density information and further converted into digital data.

[0007] In the IPS, B, G, R
Color separation signal, and apply various data processing to improve the color reproducibility, gradation reproducibility, definition reproducibility, etc., and convert the color signal of the development process color on / off Output to IOT. END conversion module 1
01 is adjusted (converted) to a gray-balanced color signal
The color masking module 102
Is to convert the B, G, and R signals into signals corresponding to the amounts of Y, M, and C color materials by performing a matrix operation. The document size detection module 103 performs document size detection at the time of prescanning and platen color erasing (frame erasing) processing at the time of document reading scanning. The color conversion module 104 is input from the area image control module. The specified color is converted in a specific area according to the area signal. And U
A CR (Under Color Removal; under color removal) & black generation module 105 generates an appropriate amount of K so that color turbidity does not occur, and reduces Y, M, and C by an equal amount according to the amount, and also performs a mono color mode. The gate of the K signal and the signals after the undercolor removal of Y, M and C are removed in accordance with each signal of the 4 full color mode. Spatial filter 106
Is a non-linear digital filter having a function of recovering blur and a function of removing moiré.
eproduction Control; color tone correction control) module 10
Reference numeral 7 denotes density adjustment, contrast adjustment, negative / positive inversion, color balance adjustment, and the like for improving reproducibility. The enlargement / reduction processing module 108 performs enlargement / reduction processing in the main scanning direction, and performs the enlargement / reduction processing in the sub-scanning direction by adjusting the scan speed of the document. The screen generator 109 converts a color material signal of a process color expressed in multiple gradations into a signal binarized on / off in accordance with the gradation and outputs the signal. Is the IOT interface module 11
0 is output to the IOT 115. The area image control module 111 has an area generation circuit and a switch matrix.
It has an area command memory 112, a color palette video switch circuit 113, a font buffer 114, and the like.
Various editing controls are performed.

The area image control module 311 has a configuration in which seven rectangular areas and their priorities can be set in the area generation circuit, and area control information is set in the switch matrix corresponding to each area. The control information includes color conversion, color mode such as mono color or full color, modulation select information such as photographs and characters, TRC select information, screen generator select information, and the like.
02, color conversion module 104, UCR module 105, spatial filter 106, TRC module 10
7 is used for control. The switch matrix is
It can be set by software.

The editing control module reads a manuscript, such as a pie chart, instead of a rectangle, and enables a coloring process in which a specified area having an unlimited shape is painted with a specified color. Is written in the four plane memories, and the editing command for each point of the document is set with four bits by the four plane memories.

[0010]

In recent years, networking of OA devices has been promoted, and devices have been distributed and shared. For example, in various modes, a conventional digital copying machine is used as a scanner or a printer. In this case, of the IIT, IPS, and IOT, the IIT and IOT are connected to a line together with a workstation, another computer, a facsimile, etc. directly or through the IPS. Therefore, the IPS performs input / output processing of image data with other devices, but a conventional color digital image processing apparatus such as a copying machine is not suitable for the above system.

In the conventional color digital image processing apparatus, since the IIT read signal is BGR as described above, the IOT color material signal is YMC (K),
These conversions are performed by a matrix operation. However, since these BGR signals and YMC signals are signals having characteristics unique to the IIT and the IOT, inconvenience occurs when image data is input / output to / from another system. In addition, there is a problem that compression is difficult with a BGR signal or a YMC signal.

When performing color adjustment, color conversion, and the like, the BGR signal and the YMC signal make it difficult to understand what color is actually output when each value is changed.
It is difficult for the user to use. Furthermore, in the area identification and the color identification, the BGR signal has various characteristics depending on the IIT and the connected external device. Therefore, at least at the time of the color identification, a large number of parameters are prepared depending on the input source. In other words, there is a problem that it is impossible to cope with it unless it is switched and used.

In a conventional image processing apparatus, a character and a halftone image are separated and processed, and the processing is switched for each. However, in the conventional color digital image processing apparatus, halftone printing and photographic printing are performed. I could not distinguish. For this reason, optimal processing has not been performed between the halftone printing and the photograph. Further, in character reproduction, first, it is necessary to identify a color character and a black character, and it is necessary to perform appropriate processing in the subsequent processing, which has a problem that the processing becomes complicated. Furthermore, when realizing the mono color mode, it is necessary to generate lightness (luminance) information from a signal of an input image in order to reproduce with good gradation.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to connect an external device to input / output and process an image signal regardless of the characteristics of the device. is there. Another object of the present invention is to facilitate color adjustment and identification.

[0015]

For this purpose, the present invention provides a first method for converting an input color separation signal into a signal in a uniform color space.
Color conversion means, image identification means for performing image identification processing on the signal in the uniform color space converted by the first color conversion means, and converting the signal in the uniform color space into a color material signal of the image output means A second color conversion unit that performs image processing depending on an image output unit on a color material signal converted by the second color conversion unit based on an image identification result obtained by the image identification unit. And processing means.

[0016]

[0017]

[0018]

According to the image processing apparatus of the present invention, first color conversion means for converting an input color separation signal into a signal of a uniform color space, and a signal of a uniform color space converted by the first color conversion means Image identification means for performing image identification processing in
A second color conversion unit that converts the signal of the uniform color space into a color material signal of an image output unit; and a second color conversion unit that converts the signal based on a result of image identification performed by the image identification unit. Image processing means for subjecting the color material signal to image processing dependent on the image output means, so that it is possible to perform an image identification process independent of the color material signal image output means and to output an image based on the identification result. Image adjustment processing depending on the means can be performed.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining one embodiment of the color image processing system of the present invention.

In FIG. 1, a first color conversion circuit 1 is a color separation signal B (blue), G (green), and R of a reflectance, which is read and input by, for example, a CCD sensor from image reading means.
(Red) is converted into a system value L ^* a ^* b ^* in a uniform color space. The L ^* axis of the system value represents lightness, and is expressed by a two-dimensional plane of a ^* axis and b ^* axis orthogonal to this. Represents saturation and hue. The image processing circuit 2 performs editing processing, input / output processing of image data with other systems, and other image processing based on the signals L ^* a ^* b ^* in the uniform color space. The second color conversion circuit 3 outputs a signal L ^* a ^{* in} a uniform color space ^.
b ^* is converted into color material signals Y (yellow), M (magenta) and C (cyan) of the image output means. UCR
The circuit 4 performs black plate generation and under color removal processing from the color material signal YMC. In the generation of the black plate (K), the maximum value and the minimum value of the color material signal YMC are detected by a maximum value minimum value detection circuit, and the difference between the maximum value and the minimum value is obtained by a subtractor. The value converted by the chroma function is subtracted from the minimum value by a subtractor. In the under color removal, a value K ′ obtained by converting the generated K by the UCR function is subtracted from the value of the color material signal YMC by a subtractor.

The color separation signal BGR as read is I
It is a signal with IT-specific characteristics, and it is necessary to correct the spectrum of an IIT illumination light source, the characteristics of a dichroic mirror, and the correction of variations in the color characteristics of photoelectric conversion elements, color filters, lenses, etc., and the correction of gray balance. .
Similarly, the color material signal YMCK of the image output means is a signal having characteristics unique to the IOT. Therefore, such a color separation signal BGR and a color material signal YMCK have different characteristics depending on IIT and IOT, and if these are collected and processed, the reproducibility of each signal will be different, which causes inconvenience. However, such inconvenience can be solved by inputting / outputting a signal L ^* a ^* b ^* in a standardized uniform color space.

FIG. 1 shows another embodiment of the present invention.
(B) and (c), wherein in (b) IIT71 is
The color original is separated into three primary colors B, G, and R using a CCD line sensor, and a color original is read and converted into digital image data. The γ correction circuit 72 calculates C
The BGR signal of the reflectance read by the CD sensor is corrected to a BGR signal of a brightness scale. The matrix conversion circuit 73 converts the BGR signal of the brightness scale into
For example, it is converted into a standard system value L ^* a ^* b ^* signal by a matrix operation of 3 × 3 + constants.
The matrix conversion circuit 74 calculates a standard system value L ^* a ^* b by a matrix operation of 3 × 3 + constant.
^* Is converted into a YMC color material signal of a lightness scale.
The C color material signal is converted into a halftone YMC color material signal. The IOT 76 reproduces a color image by performing exposure and development using a laser beam.

The example shown in FIG. 1C further includes an LUT 7
7, 78 and an edit control unit 79 are added. LU
T77,78 are each 2-dimensional look-up table to generate the HC signal from system value a ^* b ^* signals, and generates the a ^* b ^* from the HC signal reversed. The a ^* b ^* signals are used to determine the hue and the saturation from the values of a ^* and b ^* on a plane including the coordinate axes, and the HC signals each have the hue. And the saturation, the editing processing unit 79 can perform color adjustment by calculation such as H + ΔH, kC, and facilitate color conversion, hue / saturation conversion, and the like.
Further, the color recognition accuracy is improved, and the step of color adjustment can be made more user-friendly.

Next, an example of the configuration of an image processing apparatus to which the present invention is applied will be described. FIG. 2 is a diagram illustrating a configuration example of a signal processing system of the image processing device, and FIG. 3 is a diagram illustrating a configuration example of a mechanism of the image processing device.

In FIG. 2, the image input unit 100 includes, for example, three B, G, and R CCs arranged at right angles to the sub-scanning direction.
It has a reduction type sensor composed of a D line sensor, and performs image reading by scanning in the main scanning direction in synchronization with a timing signal from the timing generation circuit 12 while moving at a speed according to the magnification in the sub-scanning direction. It is an IIT, and is converted from analog image data into, for example, 8-bit digital image data expressed in gradation. The shading correction circuit 11 performs shading correction on the image data for variations between pixels due to various factors, and the gap correction circuit 13 performs gap correction between line sensors. Gap correction is performed by FIFO14
Is to delay image data read by an amount corresponding to the gap of the CCD line sensor so that B, G, and R image data at the same position can be obtained at the same time. An ENL (Equivalent Neutral Lightness) conversion circuit 15 performs gray balance processing of image data using a parameter corresponding to a document type, and a negative / positive inversion signal from an editing processing unit 400 described later. Accordingly, the negative / positive inversion is performed by inverting the gray for each pixel. For example, the negative / positive can be inverted only in a certain designated area.

B, G, processed by the ENL conversion circuit 15
The R image data is, for example, equalized by the matrix circuit 16a.
Color space signal L^*, A^*, B^*Is converted to Uniform color sky
Signal L between^*, A^*, B^*Are orthogonal coordinates
L on axis^*Represents lightness and a^*, B^*Is the chromaticity plane (hue,
(Saturation). The signal L in such a uniform color space^*,
a ^*, B^*To the memory system 20
Easy interface with external devices such as a computer
Color conversion, editing, and detection of image information.
Making it easier. The selector 17 includes the matrix conversion circuit 1
6a output or the interface
Selectively retrieve image data from memory system 200
Or capture both image data at the same time
This performs the processing of the tea synthesis and the watermark synthesis. That
Therefore, the selector 17 sets the composition ratio for the composite image.
It has a function to perform the constant, arithmetic processing, and synthesis processing.

The background removal circuit 18 creates a histogram of the document density by, for example, pre-scanning, detects the background density, and skips pixels having a density lower than the background density to improve the copy quality for a fogged document such as a newspaper. It is for. The document detection circuit 19 detects and stores a document size by detecting a boundary between the back surface of the black platen and the document and obtaining a circumscribed rectangle. In the background removal circuit 18 and the original detection circuit 19, of the signals L ^* , a ^* , and b ^{* in} the uniform color space, the lightness information is converted into the signal L ^*.
Is used.

The editing processing unit 400 sets an area command for performing editing processing and switching parameters and the like for each area, generates an area control signal based on the area command, and performs color editing and color processing on image data. Conversion, marker color detection, and other processing are performed. Then, the processed image data is input to the matrix conversion circuit 16a and the pictograph separation circuit (TIS circuit) 20.

For the image data after the editing processing, the matrix conversion circuit 16a converts L ^* , a ^* , b ^* to Y,
The image data is converted into M and C toner colors, and the pictorial character separation circuit 20 blocks a plurality of pixels to identify a color character / black character / pattern (character / halftone). In the under color removal circuit 21, Y and Y converted by the matrix conversion circuit 16b are used.
A black plate (K) is generated from the M and C image data according to a mono-color / full-color signal, and equal amounts of Y, M, and C are removed, and process-color image data is output. The determination is performed to generate a hue signal (Hue). Note that, when performing the identification processing in the pictogram separation circuit 20, a delay of, for example, 12 lines occurs in the area identification signal for blocking, so that a timing is taken to synchronize the hue signal and the image data with this delay. Is FIFO2
2a and 22b.

The enlargement / reduction circuit 23b enlarges / reduces the image data in accordance with the designated enlargement / reduction ratio. In the sub-scanning direction, the image input unit 100 changes the scanning speed according to the enlargement / reduction ratio. Since the enlargement process is performed, the image data is thinned out or interpolated in the main scanning direction. The enlargement / reduction circuit 23a is for performing enlargement / reduction processing of the area command so that the execution area of the area control information does not shift in response to the enlargement / reduction processing for the image data. The area control information subjected to the scaling processing is transmitted to the area decoder 24.
And is supplied to the processing of each processing block. The area decoder 24 includes an area command, an area identification signal,
Signals for switching the parameters 25 of the filter, the coefficients of the multiplier 26, and the parameters of the TRC circuit 27 are generated and distributed from the hue signal.

The filter 25 removes halftone moire and enhances the edge of a character in accordance with the spatial frequency of the image data reduced or enlarged by the enlargement / reduction circuit 23b. The TRC circuit 27 is for adjusting the density according to the characteristics of the IOT using the conversion table.
Reference numeral 29 denotes a TRC based on a signal of a development process or an area identification.
The decoder switches the parameters of the conversion table of the circuit 27. The multiplier 26 performs an operation of ax + b on the image data x using the coefficients a and b. The coefficient is switched such as through for a halftone and high γ for a character. Then, by appropriately selecting a coefficient and a conversion table for each color component used in conjunction with the TRC circuit 27, color adjustment for color characters, black characters, and patterns can be performed.
The density adjustment is performed. Further, the parameters of the filter 25 can be standardized, and the edge enhancement of the character can be adjusted by the coefficients a and b. The image data adjusted by the above is stored in the memory system, or is dot-expanded by the screen generation unit 28 of the ROS 300 and output as a halftone image.

The edit processing unit 400 performs color conversion, color edit, generation of an area control signal, and the like, and receives image data L ^* , a ^* , and b ^* from the selector 17. The LUT 415a converts the chromaticity information from a and b in a rectangular coordinate system to C and H in a polar coordinate system so that marker color and other colors can be easily detected, edited, and converted. The color conversion & palette 413 has, for example, 32 types of palettes for use in color conversion and color editing, and a delay circuit 411.
According to an area command input through a, processing such as marker color detection, color editing, and color conversion is performed on the image data L, C, and H. Then, only the image data in the area where the processing such as color conversion is performed
3 and inversely converted from C and H to a and b by the LUT 415b, the image data of the other area is directly output from the selector 416, and the above-described matrix conversion circuit 16
b.

The marker colors (three colors) detected from the image data by the color conversion & palette 413 and the 4-bit signal of the closed area are sent to the density conversion / area generation circuit 405. Density conversion
In the area generation circuit 405, FIFOs 410a and 410
If the number of black pixels among the 16 pixels is equal to or more than a predetermined number in a 4 × 4 window using b and 410c, a binarization process of “1” is performed to perform density conversion from 400 spi to 100 spi. The marker signal (closed loop or marker dot) generated in this manner is written from the density conversion / area generation circuit 405 to the plane memory 403 through the DRAM controller 402.

The marker / dot signal is filtered by a FIFO so that small dust and the like are not erroneously detected as markers.
A coordinate value generation circuit 407 detects marker dots and generates a coordinate value by delaying by 3 lines by O408 to make a 3 × 3 window, and stores it in the RAM 406. Note that this marker / dot is stored in the plane memory 40.
3, but this processing is performed to prevent erroneous detection.

The plane memory 403 is a memory for storing an area command for performing color conversion, color editing, and other area editing. For example, an area is designated from an edit pad, and the area command is written in the area. be able to. That is, the area command of the area specified by the edit pad is transferred to the graphic controller 401 through the CPU bus, and is written from the graphic controller 401 to the plane memory 403 through the DRAM controller 402. The plane memory 403 is composed of four planes,
A variety of area commands can be set.

The 4-bit area command stored in the plane memory 403 is read out in synchronization with the output of the image data, and is subjected to color conversion and editing processing in the palette, as shown in FIG.
, An ENL conversion circuit 15, a matrix conversion circuit 16, a selector 17, an under color removal circuit 21,
Further, it is used for switching parameters and the like of the filter 25, the multiplier 26, the TRC circuit 27, the screen generation unit 28, and the like via the area decoder 24. When this area command is read from the plane memory 403 and used for editing in the color conversion & palette 413, switching of parameters in the image data processing system, etc., density conversion from 100 spi to 400 spi is necessary. The processing is performed by the density conversion area generation circuit 405. The density conversion area generation circuit 405 performs 3 × 3 block formation using the FIFOs 409a and 409b, and performs data interpolation from the pattern so that the boundaries of the closed loop curve, the editing area, and the like do not become jagged, so that 100 spi to 400 spi. To density conversion. The delay circuits 411a, 411b, 1M FIFO 412 and the like are for adjusting the timing between the area command and the image data.

In the color copying machine shown in FIG. 3, a base machine 30 includes a platen glass 31 on which an original is placed on an upper surface, an image input terminal (IIT) 32, an electric system control storage section 33, and an image output terminal (IOT) 34. , A paper tray 35, and a user interface (U / I) 36. As an option, an edit pad 61,
Auto Document Feeder (ADF) 62, Sorter 6
3, and a film image reading device including a film projector (F / P) 64 and a mirror unit (M / U) 65.

The image input terminal 32 includes an imaging unit 37, wires 38 for driving the imaging unit 37,
The imaging unit 37 includes a driving pulley 39 and the like.
Primary color of light B (blue), G (green), R
The image information of the color document read out using the CCD line sensor after the color separation into (red) is converted into multi-gradation digital image data BGR and output to the image processing system. The image processing system is housed in the electrical system control housing unit 33, receives BGR image data, performs various conversions, corrections, and edits to improve color, gradation, definition, other image quality, and reproducibility. And the like, and converts the primary colors Y (yellow), M (magenta), C (cyan), and K (black) of the toner, and turns on / off the tone toner signal of the process color. It is converted into a valued toner signal and output to the image output terminal 34. The image output terminal 34 includes a scanner 40,
It has a photosensitive material belt 41, and converts image data into an optical signal at a laser output section 40a, and outputs a polygon mirror 40b, F
A latent image corresponding to the original image is formed on the photosensitive material belt 41 via the / θ lens 40c and the reflection mirror 40d, and the image is transferred to a sheet conveyed from the sheet tray 35 to discharge a color copy.

In the image output terminal 34, the photosensitive material belt 41 is driven by a driving pulley 41a, and a cleaner 41b, a charger 41c, each developing unit 41d of YMCK, and a transfer unit 41e are arranged around the photosensitive material belt 41.
e, a transfer device 42 is provided. And
The paper sent from the paper tray 35 via the paper transport path 35a is added, and in the case of four-color full-color copying, the transfer device 42 is rotated four times to transfer each of the YMCK latent images onto the paper. Is fixed from a transfer device 42 via a vacuum transfer device 43 by a fixing device 45 and discharged. SSI
(Single sheet inserter) 35b is the paper transport path 3
5a, the paper can be selectively supplied manually.

The user interface 36 is used by the user to select a desired function and instruct execution conditions. The user interface 36 includes a color display 51 and a hard control panel 52, and further includes a soft button on the screen by combining an infrared touch board 53. You can give instructions directly.

The electrical system control storage unit 33 includes a plurality of control boards configured separately for each processing unit such as the image input terminal 32, the image output terminal 34, the user interface 36, the image processing system, and the film projector 64. Further, an MCB board (machine control board) for controlling the operation of mechanisms such as the image output terminal 34, the automatic document feeder 62, and the sorter 63, and a SYS board for controlling the whole are housed.

FIG. 4 is a diagram for explaining another embodiment of the signal processing system of the color image processing apparatus of the present invention.

In the example shown in FIG. 4A, halftone dots / photographs / black characters / color characters are discriminated from the signal L ^* a ^* b ^* in the uniform color space by the TIS circuit 83, and the signals are converted from L ^* a ^* b ^*. Matrix coefficient of conversion circuit 84 for converting to YMC, UCR circuit 85 for removing under color, SF for removing moiré and edge enhancement
C86 switches each parameter of the TRC circuit 87 for performing color adjustment. Further, the example shown in FIG.
The TIS circuit 83 includes an area identification section, a color identification section, and an identification result synthesis section, and switches the parameters of the UCR circuit 85 and the TRC circuit 87 according to the result of the area identification and the color identification. The example shown in FIG. 4C is based on L ^* a ^* b ^* to Y
From the conversion circuit 84 'or BGR for converting to MC, L ^* a ^*
The color conversion is also performed simultaneously in the conversion circuit 82 'for converting into b ^* .

In this manner, the halftone printing and the photograph can be separated and subjected to the optimum processing for each of them, and the area identification based on the same parameter independent of the characteristics of the IIT and the externally connected device. And color identification processing.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the parameters of the UCR circuit, the filter, and the TRC circuit are switched according to the black character / color character / halftone region identification signal of the TIS circuit, but L ^* a ^* b ^*
The conversion may be performed by converting the coefficient of the conversion circuit for converting the color characters to YMC so that the color characters have high saturation, and for black characters and monocolors, L ^* is output as it is to improve the character reproducibility. In addition, the BGR color separation signal output from the document reading device is converted into a signal L ^* a ^* b ^* in a uniform color space.
The signal may be converted into a signal of C, YES, YCrCb, L ^* u ^* v ^* y.

[0046]

As is apparent from the above description, according to the present invention, first color conversion means for converting an input color separation signal into a signal in a uniform color space, and the first color conversion means Image identification means for performing image identification processing on a signal of a uniform color space converted by the above, second color conversion means for converting the signal of the uniform color space into a color material signal of an image output means, and the image identification means Image processing means for performing image processing depending on the image output means on the color material signal converted by the second color conversion means based on the identification result of the image performed by the image processing apparatus. Image identification processing independent of the means can be performed, and image adjustment processing dependent on the image output means can be performed based on the identification result.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining one embodiment of a signal processing method of a color image processing apparatus according to the present invention.

FIG. 2A is a diagram illustrating a configuration example of a signal processing system of the image processing apparatus.

FIG. 2B is a diagram illustrating a configuration example of a signal processing system of the image processing apparatus.

FIG. 3 is a diagram illustrating a configuration example of a mechanism of the image processing apparatus.

FIG. 4 is a diagram for explaining another embodiment of the signal processing method of the color image processing apparatus of the present invention.

FIG. 5 is a diagram illustrating a configuration example of a conventional color digital copying machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... First color conversion means, 2 ... Signal processing means, 3 ... Second color conversion means, 4 ... Under color removal means, 71 ... IIT, 72,
75: γ correction circuit, 73, 74: Matrix conversion circuit,
76 IOT, 77, 78 LUT, 79 Edit processing unit

Continued on the front page (72) Inventor Yoshiyuki Sorimachi 2274 Hongo, Ebina, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Kazuma Taniuchi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 72) Inventor Koyuki Kono 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Center (72) Inventor Kiya Wakabo 2274 Hongo Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Center (56) References JP-A-62-140549 (JP, A) JP-A-63-219271 (JP, A) US Patent 4,500,919 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/46 -1/64

Claims (1)

(57) [Claims] A first color conversion unit for converting an input color separation signal into a signal in a uniform color space; and performing an image identification process on the signal in the uniform color space converted by the first color conversion unit. Image identification means for performing, a second color conversion means for converting the signal of the uniform color space into a color material signal of an image output means, and the second color based on a result of image identification performed by the image identification means. An image processing apparatus comprising: an image processing unit that performs image processing depending on an image output unit on a color material signal converted by a conversion unit.