JPH07203231A - Color picture processor - Google Patents

Abstract

PURPOSE:To perform lots of diversified color processing with a single hardware. CONSTITUTION:A coordinate conversion circuit 40 converts an input picture comprising Rin, Gin, Bin into a color space comprising a hue H, a saturation S and a lightness L and its output is fed to a function conversion circuit 26 via a selection circuit 42. The function conversion circuit 46 is composed of a RAM storing the conversion table realizing the desired function conversion to convert the hue H, the saturation S and the lightness L respectively according to f(H), f(S), f(L). An output of the circuit 46 is applied to a coordinate inverse conversion circuit 52 via a selection circuit 48. The circuit 52 converts an HSL color space into an RGB color space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image processing apparatus, and more particularly to a color image processing apparatus suitable for color processing in image processing software on a digital full-color copying machine or a computer.

[0002]

2. Description of the Related Art Conventionally, in a color image processing apparatus in a color copying machine, the function of converting the color of an image has a color conversion process of converting a specific color of a primary color image into another color and an image of a plurality of colors. There are a monochromatic conversion process for converting a color into a monochromatic image, a color balance adjustment process, and a posterization for reducing the number of colors of an image to make it into a poster image, which are realized by independent circuits.

In color conversion processing for changing a specific color in a primary color image to another color, the following method is known as a method for determining the specific color. Whether or not the colors are the same can be determined by whether or not the ratios of the red signal R, the green signal G, and the blue signal B match within a certain allowable error range. For example,
The maximum value M1 of R1, G1, and B1 is selected, the ratio with other two colors is calculated, and the pixels that meet the following formula are determined to be the same color, that is, the specific color. For example, when M1 = R1, for input pixel signals (R, G, B), R × (G1 / M1) × α1 ≦ G ≦ R × (G1 / M1) × α2 R × (B1 / M1) × β1 ≦ G ≦ R × (B1 / M1) × β2 M1 × γ1 ≦ R ≦ M1 × γ2 However, α1, β1, γ1 is 1 or less, α2, β2, γ2 is 1 or more, and these setting values are set. The allowable error for determining the same color is determined. By replacing all the pixels of the specific color determined to be the same color with the colors (R2, G2, B2), a color-converted image having a solid density can be obtained.

Further, the maximum value M2 (for example, M2 = R2) of R2, G2 and B2 is selected, and the ratio with the other two colors is taken,
R value is (R1 × (R2 / M2)), G value is G1 × M1,
By setting the B value to (B1 × (B2 / M2)), it is possible to perform color conversion of a specific color while maintaining its gradation.

In the monochromatic conversion process for converting an image of a plurality of colors into a monochromatic image of an arbitrary color, designated colors (R1, G1, B1) are converted into density signals (C1 (cyan), M1 (magenta), Y1).
(Yellow) and BK1 (black)), and the maximum value MX therein is stored. Input image signal (R, G,
A signal ND (NEUTRAL DENCITY) representing the density from the signal (C, M, Y) obtained by converting B) into a density signal.
Is calculated according to the following formula. That is, ND = (C + M + Y) / 3. For example, when MX = C1, the density (Co, Mo, Yo, Bko) of the pixel of interest is: Co = ND × MX Mo = ND × (M1 / MX) Yo = ND × (Y1 / MX) Bko = ND X (BK1 / MX). As a result, images having the same color but different densities can be obtained.

In color balance adjustment for adjusting the tint of an image, different gains / offsets are set for the respective colors in the F-value correction table for each color, and the color tones when the colors overlap are set. adjust.

In posterization, for example, the lower 6 bits of the RGB input signal are fixed, and each color has 4 gradations. As a result, a limited color image of 64 colors can be obtained.

[0008]

In the conventional example, since each function is realized by a separate circuit, the larger the number of functions, the larger the circuit and the higher the cost.

When a general user adjusts the color balance, for example, the R, G, B) system is adjusted to (C, M, Y,
It is necessary to perform the adjustment operation for each color component after conversion to the BK) system, and long experience, that is, skillful technique, is required to perform intuitive adjustment such as “brighter” or “slightly bluish”.

It is an object of the present invention to provide a color image processing device which can realize the above-mentioned various functions with a simple circuit configuration.

Another object of the present invention is to provide a color image processing apparatus which can be easily operated by general users.

[0012]

A color image processing apparatus according to the present invention uses an input image signal represented by three primary colors as a hue,
A coordinate conversion means for converting into three coordinates of saturation and lightness, a function conversion means for converting the output of the coordinate conversion means into a function according to a selectable predetermined function, and an output of the function conversion means for three.
It is characterized by comprising coordinate reverse conversion means for performing reverse conversion into a primary color image signal.

[0013]

By properly selecting the function in the function converting means, various functions can be realized.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic block diagram of an embodiment of the present invention, and FIG. 2 shows a schematic functional block diagram of a digital full-color copying machine using the embodiment shown in FIG.

First, FIG. 2 will be described. FIG. 2 shows a digital full-color copying machine to which the present embodiment is applied as functional blocks focusing on the flow of processing. 10
Converts the reflected light from the original into an electric signal by color separation 3
Line CCD type line sensor, 12 is an A / D converter for converting an analog RGB output signal of the line sensor 10 into a digital signal, and 14 is an output of the A / D converter 12 for each pixel of the line sensor Shading correction circuit that corrects the output unevenness and the inclination of the light amount of the light source,
An input masking circuit that corrects the RGB spectral characteristics of the sensor 10 into a standard RGB space.

Reference numeral 18 denotes a color processing circuit for performing various color-related conversions, which has the circuit configuration shown in FIG. Reference numeral 20 denotes a color space compression circuit that compresses an image signal distributed in the standard RGB space into a range that can be reproduced by an output device (printer).
Is a light amount / density conversion circuit for converting the RGB luminance signal into a density signal composed of cyan (C), magenta (M), and yellow (Y). 24 is a three-color density signal C,
An undercolor removal (UCR) and output masking circuit that corrects M and Y in accordance with the spectral characteristics of the toner and at the same time generates a black signal BK and outputs the black signal BK one by one in a frame-sequential manner in accordance with the recording color of the printer.

26 is a density value (F
F value correction table for correcting (value) for each color, 28 is
A scaling circuit for changing the size of the image, 30 is a spatial filter for edge-enhancing and smoothing the image, 32 is an image signal (spatial filter) to be printed out in accordance with the color characteristics of the connected printer 34. 12 is a printer characteristic correction table for correcting the output (30 output).

In the digital full-color copying machine, the original image read by the line sensor 10 is processed by the functional blocks 12 to 32 shown in FIG. 2 and then printed out by the printer 34.

Next, FIG. 1 will be described. The circuit shown in FIG. 1 is used as the color processing circuit 18 in FIG. In FIG. 1, reference numeral 40 designates an RGB color space as hue HUE (H), saturation SATURATION (S) and lightness LIGHTNE.
This is a coordinate conversion circuit for converting to the SS (L) HSL color space, and the output signals Hin, Si for the input signals Rin, Gin, Bin which are the output signals of the input masking circuit 16.
Output n and Lin. 42 is the output H of the conversion circuit 40
A selection circuit for selecting in, Sin, Lin, or HSL color space data on the CPU bus 44 (CPU address bus).

Reference numeral 46 denotes a hue (H) from the selection circuit 42,
The color components of the saturation (S) and the lightness (L) are respectively expressed by the function f.
(H), f (S), f (L) is a function conversion circuit for conversion. Specifically, the function conversion circuit 46 is composed of a RAM that stores a table of function conversion, the input is its address, and the output is a table value.

48 is the output of the function conversion circuit 46 or CP
Selector circuit for selecting data on the U data bus 50, 5
Reference numeral 2 is a coordinate inverse conversion circuit that returns the color components of the HSL color space output from the selection circuit 48 to the RGB color space. The outputs Rout, Gout, Bout of the coordinate reverse conversion circuit 52 are applied to the color space compression circuit 20 of FIG.

FIG. 3 is an explanatory diagram of the HSL color space used in the coordinate conversion circuit 40 and the coordinate inverse conversion circuit 52. By a known operation, the 8-bit image signals R, G, and B in the RGB color space are converted into H (0 ° to 360 °) and S (8 bit).
And L (8 bits). The coordinate conversion circuit 40 and the coordinate inverse conversion circuit 52 can be set to through, and the function conversion circuit 46 can also be used to convert an RGB image.

FIG. 1 shows the following cases (1) and (2) as an example.
Means for generating a monochromatic image of an arbitrary color by the circuit shown in FIG.

(1) When the lightness L is saved and the hue H and the saturation S are fixed.

In this case, first, the color information (H0, H0) of the target single color (designated color) is obtained by sampling the original image by prescanning or selecting from the registered colors.
S0, L0) is set, and the following values are written in the function conversion circuit 46.

F (H) = H0 (constant) f (S) = S0 (constant) f (L) = L (through) The input image composed of Rin, Gin, and Bin is the circuit 4
After passing through 0 and 42, it is input to the function conversion circuit 46, and in the function conversion circuit 46, the hue H and the saturation are fixed to constant values H0 and S0. The output of the function conversion circuit 46 is applied to the coordinate reverse conversion circuit 52 via the selection circuit 48 and returned to the RGB color space. Outputs Rput, Gou of the coordinate reverse transformation circuit 52
In t and Bout, the lightness is still input, and the hue and saturation are images fixed to constant values.

In this conversion, "black" in the original remains "black" after conversion. The same pixel as the designated color has the same color before and after conversion.

(2) The lightness L is compressed so that "black" of the original corresponds to "designated color".

At this time, f (H) = H0 (constant) f (S) = S0 (constant) f (L) = (L × (255−L0) / 255) + L0 is set in the function conversion circuit 46. L0 is a constant that determines the minimum brightness after compression and the slope of compression. In this conversion, "black" in the original image is converted into the designated color having the lowest lightness.

Even if the value of the hue H is constant, different colors may appear due to the characteristics of the printer and the distortion of the color space. Function f (H), f considering the correction function
(S) and f (L) may be set in the function conversion circuit 46.

In this embodiment, by changing the functions f (H), f (S) and f (L) set in the function conversion circuit 46, for example, HSL posterization can be easily realized. In this case, f (H) = int (H / 30) f (S) = 0 (when S = 0) = int (S / 128) (S ≠ 0) f (L) = int (L / 64) is set in the function conversion circuit 46. int () is a function for obtaining an integer, as is well known.

In the case of hue / saturation / contrast adjustment, f (H) = H + δH f (S) = S + δS f (L) = L + δL. δH, δS, δL are bias or offset values for adjustment.

The combination of the above processes can be realized by using a composite function of the functions of the respective processes. It is obvious that other processing can be realized by appropriately setting the functions f (H), f (S), f (L). Further, by setting the coordinate conversion circuit 40 and the coordinate inverse conversion circuit 52 to be through, processing such as posterization for reducing the gradation of each color in the RGB color space and solarization for inverting the gradation from the middle for each color. Can also be realized.

In the above embodiment, the HSL is converted from the RGB color space.
The coordinate conversion to the color space is taken as an example, but the hue, saturation, and
Since the coordinate system having the three coordinates of lightness is not limited to the above example, for example, conversion from the L * a * B * space to polar coordinates can be used.

In order to be able to set the above-mentioned various functions to an arbitrary area within one screen, it is sufficient to select a function conversion function for each designated area. FIG. 4 shows a schematic block diagram of the embodiment.

In FIG. 4, 60 is an area code signal AREA indicating the area to which the pixel of interest belongs, a CPU address (address bus) 62 or CPU data (data.
(Bus) 64 for selecting circuit, 66 for selecting circuit 60
It is an area code RAM that outputs a selection signal for selecting a function to be used in function conversion according to the output of. The area code RAM 66 stores in advance a code (address signal) that specifies a function conversion function to be performed in each area.

68 is a coordinate conversion circuit similar to the coordinate conversion circuit 40, and 70 is outputs Hin, Si of the coordinate conversion circuit 68.
n, Lin and output of area code RAM 66, or
A selection circuit for selecting HSL color space data on the CPU bus 62 (CPU address bus) and data in place of the output of the area code RAM 66.

Reference numeral 72 denotes a selection output of the selection circuit 70.
Function f (H, AREA), f according to area code
(S, AREA), f (L, AREA) hue (H),
It is a function conversion circuit that performs function conversion of color component data of saturation (S) and lightness (L). 74 is a selection circuit for selecting the output of the function conversion circuit 72 or data on the CPU bus (data bus) 64, and 76 is an H output from the selection circuit 74.
It is a coordinate reverse conversion circuit that returns the color components of the SL color space to the RGB color space. Outputs Rout, Gou of the coordinate reverse conversion circuit 76
t and Bout are applied to the color space compression circuit 20 of FIG.

In FIG. 4, the area code signal AREA
Indicates an area to which the pixel of interest belongs in synchronization with the image signal. The signal AREA is input to the area code RAM 66 via the selection circuit 60. A processing code to be applied to an arbitrary designated area is written in the RAM 66 in advance, and its output is an upper bit of the function converting RAM used in the function converting circuit 72. In this way, the conversion function used in the function conversion circuit 72 can be switched for each area by changing the processing code, and a plurality of color processes can be applied to each arbitrary area within one screen. Since other operations are the same as those in FIG. 1, description thereof will be omitted.

In the HSL coordinate system of the embodiment shown in FIG. 1, due to its characteristics, even if one H value is designated, the printing color may differ considerably depending on the S value and the L value. FIG. 5 shows an example of an apparent hue of L. In this example, for example, H = 20
When a user's color of 0 ° is set, the lighter (higher lightness) aims for “blue”, but the darker (lower lightness) looks like a color closer to cyan.

Therefore, when converting H in the entire range of L (hue conversion and user's color), it is desirable to use the L conversion table as an H correction coefficient table to correct the characteristics of the coordinate system. FIG. 6 shows a circuit configuration of the color processing circuit 18 which realizes this function.

In FIG. 6, reference numeral 80 is a selection circuit for selecting the area code signal AREA indicating the area to which the pixel of interest belongs or the CPU address (address bus) 82, and 86.
Is an area code RAM that outputs a selection signal for selecting a function to be used in function conversion and a 1-bit correction mode signal according to the output of the selection circuit 80. Area code RA
In M86, a code (address signal) designating a function conversion function to be applied in each area and a correction mode signal indicating presence / absence of correction in that area are stored in advance.

Reference numeral 88 is a coordinate conversion circuit similar to the coordinate conversion circuit 40, 90 is a selection circuit similar to the selection circuit 70, 92 is a function conversion circuit similar to the function conversion circuit 72, and 94 is similar to the selection circuit 74. A selection circuit for selecting the output of the function conversion circuit 92 or the data on the CPU bus (data bus) 84.

Reference numeral 96 denotes H out of the selection output of the selection circuit 94.
A calculation circuit for calculating the component and the L component, 98, according to the correction mode signal output from the area code RAM 86,
A selection circuit for selecting the H component output, the S component output, and the L component output of the selection circuit 94, or the output of the arithmetic circuit 96, the S component output of the selection circuit 90, and the L component output of the selection circuit 90,
Reference numeral 100 designates the output of the selection circuit 98 as the coordinate inverse transformation circuit 76.
Similarly to the above, it is a coordinate reverse conversion circuit for returning from the HSL color space to the RGB color space. The output Rout of the coordinate reverse transformation circuit 100,
Gout and Bout are applied to the color space compression circuit 20 of FIG.

The processing by the circuits 88, 90, 92 and 94 is the same as in FIG. When the H correction mode is set, the area code RAM 86 stores f (H,
An address value for selecting the H correction coefficient table is stored as AREA). As a result, the function conversion circuit 92 outputs the H correction coefficient to the L component output in the H correction mode. The arithmetic circuit 96 calculates the H correction coefficient into the H component and outputs the corrected H signal. The selection circuit 98 follows the correction mode signal from the area code RAM 86,
The output of the arithmetic circuit 96, the S component output of the selection circuit 90, and the L component output of the selection circuit 90 are selected. As a result, the selection circuit 98 outputs the signal in which only the hue is corrected while the S component and the L component remain unchanged. In this way, when a single hue is used over the entire lightness range, the difference in color due to lightness can be reduced.

In the embodiment shown in FIG. 6, the circuit scale is reduced by using the L conversion table and the H correction table in common, but the hue correction means is not limited to this configuration. For example, a correction circuit is provided before the H conversion function, and the brightness L
The hue H and, if necessary, the saturation S may be corrected before the function conversion.

In modes other than the H correction mode, the selection circuit 98
The H component output, S component output, and L component output of the selection circuit 94 are selected. Other functions and effects are the same as those in FIG.

In the embodiment shown in FIG. 1, for example, in the process of "making red into blue", the conversion function as shown in FIG. 7, that is, the conversion table is used, and from "white" to "black",
All colors with a hue close to red are converted to blue. On the other hand, a color processing function that limits saturation and lightness, that is, "makes only bright red blue" is desired. In order to realize this function, each signal value of H, S, and L is compared with each signal value of "specific color" by a window comparator, and color conversion is performed only when all components are within a certain distance from the specific color. You can do it.

FIG. 8 shows a schematic block diagram of an embodiment configured as such as the color processing circuit 18. The same components as those in FIG. 1 are designated by the same reference numerals. In FIG.
Reference numerals 102, 104, 106, 108, 110, and 112 denote the upper limit value of the hue H, the lower limit value of the hue H, the upper limit value of the saturation S, the lower limit value of the saturation S, the upper limit value of the lightness L, and the lower limit value of the lightness L, respectively. A register for holding a value, 114 is a coordinate conversion circuit 40
The H, S, and L values output from the registers 102 to 112
It is a determination circuit that compares with the corresponding upper and lower limit values of to determine whether all the components are within the specified range. The registers 102 to 112 and the determination circuit 114 form a window comparator.

According to the determination result of the determination circuit 114, when H, S and L are all within the designated range, 116 selects the RGB output of the coordinate reverse conversion circuit 52 and designates even one of H, S and L. Input Rin, Gin, Bin when not within the range
Is a selection circuit for selecting. The output of the selection circuit 116 is
The color processing circuit 18 is used as Rout, Gout, and Bout.
Will be output.

The determination circuit 114 compares the H value output from the coordinate conversion circuit 40 with the upper limit value and the lower limit value of the registers 102 and 104, and the S value output from the coordinate conversion circuit 40 to the upper limit values of the registers 106 and 108. The L value output from the coordinate conversion circuit 40 is compared with the value and the lower limit value to register 1
Compare with the upper and lower limits of 10,112. And
When all of the H value, S value, and L value are within the range limited by the upper limit value and the lower limit value, the determination circuit 114
Outputs "1", and outputs "0" when even one does not fall within the range. The selection circuit 116 is the determination circuit 1
When the output of 14 is "1", RG of the coordinate reverse conversion circuit 52
When the output B is selected and the output of the determination circuit 114 is "0", the inputs Rin, Gin and Bin are selected.

By inverting the output of the judgment circuit 114 as necessary, for example, a function of erasing only the red pen portion in the correction original (designating "red" and replacing the corresponding portion with white) and only the red pen It is possible to selectively realize both of the function of leaving (designating "red" and replacing the part other than red with white).

It is necessary to change the upper limit value and the lower limit value of the registers 102 to 112 depending on whether "red" is detected or "white" is detected by color conversion.

For example, "red (H = 0, S = 255, L =
128) ”, it is assumed that the registers 102 to 112 have set −10 ≦ H ≦ 10 255-50 ≦ S ≦ 255 + 50 128-50 ≦ L ≦ 128 + 50. With the same setting, "white (H = undefined,
S = 0, L = 255) ”,
Hue cannot be set (that is, includes all H) "white"
Among them, only those in which H happens to be close to the set value are selected and become mottled. In addition, even L having a density of about 50 is selected. To prevent this, when a value close to “white” is selected as the “specific color”, for example, H = entire range (or no range designation) −10 ≦ S ≦ 10 255-10 ≦ L ≦ 255 + 10. , Change the window settings.

Not limited to this, for example, since there is a difference in appearance that a bright color is easier to understand than a dark color and that “blue” has a smaller change in appearance than “red”, these are taken into consideration. Then, by changing the setting value of the window, it is possible to determine the specific color that is closer to the appearance.

Actually, the CPU (not shown) has a table of "specific color" and "window setting value" in advance, and automatically sets the window setting value, that is, the registers 102 to 112 according to the user's "specific color" designation. Select a hold value for.

When a specific color judgment is made in a window for a color halftone dot original such as a printed matter, as shown in FIG. 9, the judgment result becomes dot-like depending on the halftone dot, and the converted color is the designated color. The appearance may be different, and the image may be rough. Therefore, a smoothing circuit is provided before coordinate conversion, and the R, G, B or H, S, L values are rounded before the color determination. As a result, the portion having the same color and the determination portion are visually matched. Figure 10
The schematic block diagram of the Example is shown. The embodiment shown in FIG. 10 is different from the embodiment shown in FIG. 8 in the coordinate conversion circuit 4.
The smoothing circuit 118 is provided in the subsequent stage of 0. Further, the determination signal processing circuit 1 that processes the determination result of the determination circuit 114
20 is provided and the selection circuit 116 is controlled by the output of the determination signal processing circuit 120. Selection circuits 43 and 4
Since 8 is unnecessary, it has been deleted.

In this embodiment, Rin, Gin, Bin
It is assumed that the resolution of the input image represented by is 400 dpi, and the 5 × 5 smoothing circuit 118 has a screen frequency of 133 to 175 dpi which is the screen frequency of a halftone dot of a general printed matter.
To lick. The determination signal processing circuit 120 thickens or thins a portion where the determination result is deviated due to a change between colors, by a majority vote or the like. Other functions and effects are the same as those in FIG.

In the smoothing circuit 118, where the hue signal H is processed, the hue signal H makes one rotation at 360 °. Therefore, in addition to the product sum calculation circuit common to S and L, the actual value of the signal value is added. A preprocessing circuit for calculating the distance is provided.

In the embodiment shown in FIG. 10, an image signal that is not subjected to color processing is output for pixels that do not fall within the specified range. This prevents unnecessary reduction in resolution due to smoothing of the smoothing circuit 118. Alternatively, the signal smoothed by the smoothing circuit 118 may be input only to the determination circuit 114 to reduce resolution deterioration due to smoothing.

In the embodiment shown in FIG. 10, the HSL signal is smoothed, but the input RGB signals Rin, Gi
Alternatively, n and Bin may be smoothed, converted into HSL signals, and then judged by the judgment circuit 114.

It is obvious that the color space compression circuit 20 shown in FIG. 2 can be integrated with the color processing circuit 18 having the configuration described above. FIG. 11 is a diagram showing a color space when the color space compression circuit 20 is integrated with the color processing circuit 18. 0 ° (R), 60 ° (Y), 12 during prescan
0 ° (G), 180 ° (C), 240 ° (B) and 30
In each hue of 0 ° (M), the signal value with the highest saturation S is sampled. This value is compared with the maximum value of the printer reproducible color space, and if the image contains a value that cannot be reproduced by the printer, the saturation component of the hue component is compressed to be reproducible.

When each color processing function is executed thereafter, the color space compression function obtained by the prescan and the function for each processing are combined and written in the RAM of the conversion circuits 46, 72 and 92.

[0065]

As can be easily understood from the above description, according to the present invention, RGB signals are converted into a cylindrical coordinate system having a hue H, a saturation S and a lightness L, and various conversions are performed in the coordinate system. By performing the processing, various functions can be realized with a single hardware. Further, there is an advantage that the color designation becomes intuitive.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a first embodiment of the present invention.

FIG. 2 is a functional block diagram of image processing of a digital full-color copying machine using this embodiment.

FIG. 3 is a diagram showing an HSL color space used in the embodiment shown in FIG.

FIG. 4 is a schematic block diagram of a second embodiment of the present invention.

FIG. 5 is an example of a change in appearance color according to brightness.

FIG. 6 is a schematic block diagram of a third embodiment of the present invention.

[FIG. 7] Conversion table f for the process of “making red into blue”
It is an example of (E), f (S), and f (L).

FIG. 8 is a schematic block diagram of a fourth embodiment of the present invention.

FIG. 9 is an example of a determination result when a specific color is determined from a color halftone dot original.

FIG. 10 is a schematic block diagram of a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a color space.

[Explanation of symbols]

10: Line sensor 12: A / D converter 14: Shading correction circuit 16: Input masking circuit 18: Color processing circuit 20:
Color space compression circuit 22: Light intensity / density conversion circuit 24: Under color removal (UCR) and output masking circuit 26: F value correction table 28: Magnification circuit 30: Spatial filter
32: printer characteristic correction table 34: printer 4
0: Coordinate conversion circuit 42: Selection circuit 44: CPU address bus 46: Function conversion circuit 48: Selection circuit 5
0: CPU data bus 52: Inverse coordinate conversion circuit 6
0: selection circuit 62: CPU address (or address
Bus) 64: CPU data (or data bus) 6
6: Area code RAM 68: Coordinate conversion circuit 70:
Selection circuit 72: Function conversion circuit 74: Selection circuit 76: Inverse coordinate conversion circuit 80: Selection circuit 82: CPU address (or address bus) 8
4: CPU bus (data bus) 86: Area code RAM 88: Coordinate conversion circuit 90: Selection circuit 92:
Function conversion circuit 94: Selection circuit 96: Operation circuit 98: Selection circuit 1
00: Inverse coordinate conversion circuit 102: Hue H upper limit register 104: Hue H lower limit register 106: Saturation S upper limit register 10
8: Lower limit value register of saturation S 110: Upper limit value register of lightness L 112: Lower limit value register of lightness L 114:
Judgment circuit 116: Selection circuit 118: Smoothing circuit 120: Judgment signal processing circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 1/46 Z

Claims (9)

[Claims] 1. Coordinate conversion means for converting an input image signal represented by three primary colors into three coordinates of hue, saturation and lightness,
A color characterized by comprising a function converting means for converting the output of the coordinate converting means into a function according to a selectable predetermined function, and a coordinate reverse converting means for reverse converting the output of the function converting means into three primary color image signals. Image processing device. 2. The color image processing apparatus according to claim 1, wherein the coordinate conversion means and the coordinate inverse conversion means include through means. 3. The color image processing apparatus according to claim 1, wherein the function conversion means is capable of selecting a function to be applied to each of the plurality of designated areas. 4. The color image processing apparatus according to claim 1, wherein the function conversion unit includes a distortion correction unit. 5. Further, according to the output of the coordinate conversion means, 1
The color image processing apparatus according to claim 1, further comprising a specific color detection unit that detects the specific color. 6. The color image according to claim 1, further comprising smoothing means for smoothing the output of the coordinate conversion means, and specific color detecting means for detecting one or more specific colors according to the output of the smoothing means. Processing equipment. 7. The color image processing apparatus according to claim 6, further comprising an isolated point removing means for removing isolated points from the output of the specific color detecting means. 8. The color image processing apparatus according to claim 5, wherein the one or more specific colors are changeable. 9. The color image processing apparatus according to claim 1, wherein the function conversion unit is a color space compression unit.