JPH06101790B2 - Color correction method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color correction method for a color image recording apparatus generally called a color printer or a color copy.

In particular, the color category specified by the user, for example Category 1
The present invention relates to a color correction method capable of changing only the yellow to red colors into a delicate color (hue or the like) desired by the user.

[Prior Art] A conventional example will be described with reference to FIG.

FIG. 16 is a plan view showing a part of an operation panel of a color image recording apparatus using a conventional color correction method.

In FIG. 16, an operation panel (1) of a color image recording apparatus using a conventional color correction method is shown as a red key (11a), a green key (11b), a blue key (11c) and a full color key (11).
Concentration adjustment key (11) equipped with d) and concentration display lamp (1
2) and other operation keys.

Next, the operation of the above-described color image recording apparatus and the conventional color correction method will be described.

Color correction is performed by the density adjustment key (1
1). That is, if the user wants to change the density of red, green or blue, the red key (11a),
Press the green key (11b) or blue key (11c). Also, if you want to change the density of all colors, full color key (11d)
push. By these operations, the levels of the red, green, and blue signals as a whole fluctuate, and as a result, the levels of the Y, M, and C signals of the print output fluctuate as a whole. For example, when the red key (11a) is pressed, the densities of colors other than red also change, and a color image with an increased redness is obtained.

[Problems to be Solved by the Invention] In the conventional color correction method as described above, three colors of red, green, and blue are used.
There is a problem that it is possible to select and change from the colors, and it is also possible to change colors other than the selected color, so that it is not possible to change only the color that the user wants to change to a delicate color desired.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to obtain a color correction method capable of changing only a color of a color section desired to be changed by a user to a desired delicate color.

[Means for Solving the Problems] The color correction method according to the present invention comprises the following steps.

(I) A step of designating a color segment to be color-corrected in a color image signal composed of N colors classified into N factorial color segments.

(Ii). Specifying a function that determines the amount of change in color of the color segment to be color-corrected.

(Iii). A step of obtaining an M (= 1, 2, 3, ..., N) -order color component corresponding to the color classification from the input color image signal.

(Iv). Converting the Mth order color component based on the function.

(V). A step of adding the converted Mth-order color component for each N color signal to obtain a color image signal in which only the color of the designated color section is color-corrected.

[Operation] In the present invention, in the first step, the color section to be color-corrected is designated in the color image signal composed of N colors classified into N factorial color sections.

Further, in the second step, a function that determines the amount of change in color of the color section to be color-corrected is specified.

Further, in the third step, from the input color image signal, M (= 1, 1,
2, 3, ..., N) Next color components are determined.

Furthermore, in the fourth step, the Mth order color component is converted based on the function.

Then, in the fifth step, the converted M
The next color component is added for each of the N color signals to obtain a color image signal in which only the colors in the designated color section are color-corrected.

Therefore, according to the present invention, it is possible for the user to change only the color of the color segment that he wants to change to a color that is subtly desired.

[Embodiment] An embodiment of the present invention will be described with reference to FIGS. 1 to 6.

1 to 6 are flowcharts showing an embodiment of the present invention.

First, regarding the first and second steps of the present invention,
That is, a step of designating a color segment to be color-corrected in a color image signal consisting of N colors classified into N factorial color segments, and a color change amount of the color segment to be color-corrected are described. The step of designating the determining function will be described with reference to FIGS. 1 and 2.

A display device and a keyboard constituting the electronic computer system interactively input information about a color segment to be color-corrected and a function for determining a color change amount of the segment.
The question displayed on the display device is represented by “”, and the response input by the user with the keyboard is represented by “”. The user is assumed to have some knowledge about colors and color printing.

In step (101), the electronic computer displays on the display device the question of the color to be corrected by the user, as shown below.

"Please select and enter the color you want to correct from the following.

“Y”, “M”, “C,“ R ”,“ G ”,“ B ”,“ K ”If there is no color you want to correct, enter“ N ”.” In step (102) , Input the color response you want to correct from the keyboard and save. The user responds, for example, as shown below.

In the "Y" step (103), it is determined whether there is a color to be color-corrected, that is, whether the color to be color-corrected is other than "N". If it is other than "N" (YES), the process proceeds to step (104). If it is "N" (NO), this process ends.

In step (104), it is determined whether the color to be color-corrected is "Y". If "Y" (YES), step (105)
If it is not "Y" (NO), the process proceeds to step (106).

In step (105), "Y" is processed, and the process returns to step (101).

In step (106), it is determined whether the color to be color-corrected is "M". If "M" (YES), go to step (107).
If it is not "M" (NO), go to step (108).

In step (107), the process of "M" is performed, and the process returns to step (101).

In step (108), it is determined whether the color to be color-corrected is "C". If "C" (YES), go to step (109)
If it is not "C" (NO), proceed to step (110).

In step (109), the process of "C" is performed, and the process returns to step (101).

In step (110), it is determined whether the color to be color-corrected is "R". If "R" (YES), step (111)
If it is not "R" (NO), proceed to step (112).

In step (111), the process of "R" is performed, and the process returns to step (101).

In step (112), it is determined whether the color to be color-corrected is "G". If "G" (YES), step (113)
If it is not "G" (NO), the process proceeds to step (114).

In step (113), the process of "G" is performed, and the process returns to step (101).

In step (114), it is determined whether the color to be color-corrected is "B". If "B" (YES), go to step (115)
If it is not "B" (NO), proceed to step (116).

In step (115), the process of "B" is performed, and the process returns to step (101).

In step (116), "K" is processed, and the process returns to step (101).

In this way, the user selects one or two or more colors to be color-corrected.

Regarding the processing of "Y" in step (105) of FIG.
Description will be given with reference to the drawings.

In step (151), the electronic computer displays a question of color classification on the display device, as shown below.

"The color of shaded areas: Category 1: yellow to red, Category 6: green to yellow changes. Enter the color category you want to correct." In step (152), enter the response of the color category from the keyboard. Enter from and save. The user responds, for example, as shown below.

In the "1" step (153), it is determined whether the color classification is "1". In the case of "1" (YES), the process proceeds to step (154) to process the color division 1 thereafter, and when it is not "1" (NO), that is, in the case of the color division "2", the step (154) Proceed to 159).

In step (154), the function type question is displayed on the display device, as shown below.

"You can change the amount of Y, M, and C with the following function formula for the amount of Y1.

TY1 = YY * Y1 TM1 = YM * Y1 TC1 = YC * Y1 Input the functions YY, YM and YC. If you do not want to change it, press the return key without entering anything. In step (155), the function type response is entered from the keyboard and saved. The user responds, for example, as shown below.

“2/3, 1/3, 1/3” In step (156), a confirmation question is displayed on the display device as shown below.

“As shown in the graph, Y, M, and C change. Are you sure? (YorN) TY1 = 2/3 * Y1 TM1 = 1/3 * Y1 TC1 = 1/3 * Y1” Step (157 ), Enter the confirmation response from the keyboard and save. The user responds, for example, as shown below.

“Y” In step (158), it is determined whether the confirmation is OK. If not OK (NO), the process returns to step (154) to input another function. If OK (YES), this process ends.

In step (159), the above-mentioned steps (154)-
The same color classification 2 processing as (158) is performed, and this processing ends.

In addition, the steps (151), (154) and (156) described above.
Question, we will explain later in Fig. 9 (a) and Fig. 11 (b).
And the graph of FIG. 11 (c) is displayed at the same time.

In addition, the process of "M" in step (107) shown in FIG.
Process "C" in step (109), "R" in step (111)
Process, step (113) “G” process, step (11
The process "B" in 5) and the process "K" in step (116) are the same as the process "Y" described above.

Next, for the third to fifth steps of the present invention, that is, the M (= 1, 2, 3, ..., N) -order color component corresponding to the color segment is obtained from the input color image signal. And a step of converting the M-th order color component based on the function, and adding the converted M-th order color component for each N color signal, so that only the color of the designated color section is colored. The steps of obtaining the corrected color image signal will be outlined with reference to FIG. The color image signals of three colors of Y, M, and C will be described as an example.

In step (200), the electronic computer determines any one of color categories 1 to 6 based on the magnitude relationship among the signal levels IY, IM, and IC of the Y, M, and C signals before color correction, and the primary computer Two
Next, the third and third color components are obtained.

In step (300), 1 for each color category 1-6
Each color component is converted based on the designated function using the secondary, secondary, and tertiary color components as variables.

In step (400), the converted primary, secondary, and tertiary color components are added for each Y, M, C signal, and the signal levels TY, RM, of the new color-corrected Y, M, C signals are added. Set as TC and end this process.

The details of the third step of the present invention, that is, the step of obtaining the M (= 1, 2, 3, ..., N) -order color component corresponding to the color classification from the input color image signal are described above. This will be described with reference to FIG. 4 corresponding to the step (200).

In the process shown in FIG. 4, the color classification is judged and the primary to tertiary color components are calculated for each classification.

In step (201), the electronic computer judges whether the level IY of the Y signal is higher than the level IM of the M signal in the input color image signal, and if IY> IM (YE
S) proceeds to step (202), and if IY ≦ IM (NO) jumps to step (207).

In step (202), it is determined whether the level IM of the M signal is greater than or equal to the level IC of the C signal,
If IM ≧ IC (YES), proceed to step (203), where IM <IC
In the case of (NO), jump to step (204).

In step (203), the level of each signal is IY> IM ≧ I
Since it is a relationship of C, the color classification is set to "1". As an actual program, this division “1” is stored in a predetermined memory. In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: Y1 = IY-IM, the secondary color component: Y2 = IM-IC, and the tertiary color component: Y3 = IC.

In step (204), it is determined whether the level IY of the Y signal is greater than or equal to the level IC of the C signal,
If IY ≧ IC (YES), proceed to step (205), where IY <IC
In the case of (NO), the process proceeds to step (206).

In step (205), the level of each signal is IY ≧ IC> I
Since it is an M relationship, the color classification is set to "6". In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: Y1 = IY-IC, the secondary color component: Y2 = IC-IM, and the tertiary color component: Y3 = IM.

In step (206), the level of each signal is IC>IY> I
Since it is an M relationship, the color classification is set to "5". In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: C1 = IC-IY, the secondary color component: C2 = IY-IM, and the tertiary color component: C3 = IM.

In step (207), it is determined whether the level IM of the M signal is higher than the level IC of the C signal. If IM> IC (YES), the process proceeds to step (208), and if IM ≦ IC (NO).
Fly to step (211).

In step (208), it is determined whether the level IY of the Y signal is higher than the level IC of the C signal. If IY> IC (YES), the process proceeds to step (209), and if IY ≦ IC (NO).
Proceeds to step (210).

In step (209), the level of each signal is IM ≦ IY> I
Since it is a relationship of C, the color classification is “2”. In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: M1 = IM-IY, the secondary color component: M2 = IY-IC, and the tertiary color component: M3 = IC.

In step (210), the level of each signal is IM> IC ≧ I
Since the relationship is Y, the color classification is "3". In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: M1 = IM-IC, the secondary color component: M2 = IC-IY, and the tertiary color component: M3 = IY.

In step (211), the level of each signal is IC ≧ IM ≧ I
Since it is a Y relationship, the color classification is set to "4". In addition, the primary to tertiary color components are obtained from the level difference of each signal, and this processing ends. That is, the primary color component: C1 = IC-IY, the secondary color component: C2 = IM-IY, and the tertiary color component: C3 = IY.

The fourth step of the present invention, that is, the step of converting the M-th order color component based on the function will be described in detail with reference to FIG. 5 corresponding to the above step (300).

In the process shown in FIG. 5, the primary to tertiary color components for each color segment are converted based on the designated function.

In step (301), the electronic computer determines whether or not the color classification of the pixel of the input color image signal is "1". If it is classification 1 (YES), the process proceeds to step (302). In the case of (NO), the process proceeds to step (303).

In step (302), when the color classification is "1", the conversion of the primary to tertiary color components is performed by the following functional expression, and this processing ends.

That is, in the primary color component conversion, Y, M, which are determined by the functions Fy ₁ y, Fy ₁ m, and Fy ₁ c whose variables are the primary color component Y ₁ ,
The conversion amounts TY1, TM1 and TC1 of the C signal are obtained. These conversion amounts TY1, TM1, TC1 are all values that are determined by the size of the primary color component Y1.

Next, in the secondary color component conversion, Y, M, and C determined by the functions Fr ₁ y, Fr ₁ m, and Fr ₁ c having the secondary color component Y 2 as a variable.
Obtain the signal conversion amounts TY2, TM2, and TC2. These conversion amount T
Y2, TM2, TC2 are all values whose conversion amount is determined by the size of the secondary color component Y2.

Finally, in the third-order color component conversion, Y, M, which are determined by the functions Fk ₁ y, Fk ₁ m, and Fk ₁ c that convert the third-order color component Y3,
Obtain the conversion amounts TY3, TM3, TC3 of the C signal. These conversion amounts TY3, TM3, TC3 are all values that are determined by the size of the tertiary color component Y3.

That is, each conversion amount can be expressed by a functional expression as follows: primary color component conversion: TY1 = Fy ₁ y (Y1) TM1 = Fy ₁ m (Y1) TC1 = Fy ₁ c (Y1) secondary color component conversion: TY2 = Fr ₁ y (Y2) TM2 = Fr ₁ m (Y2) TC2 = Fr ₁ c (Y2) Third color component conversion: TY3 = Fk ₁ y (Y3) TM3 = Fk ₁ m (Y3) TC3 = Fk ₁ c (Y3).

In addition, regarding the other color categories 2 to 6, similarly, depending on the size of the primary color component, the secondary color component, and the tertiary color component, Y, M,
The conversion amount of the C signal is obtained by different functions.

In step (303), it is determined whether or not the color classification is "2". If it is classification 2 (YES), the process proceeds to step (304), and if it is not classification 2 (NO), the process proceeds to step (305).

In step (304), when the color classification is "2", the primary to tertiary color components are converted by the following functional expression, and this processing ends.

That is, each conversion amount is expressed by a functional expression as follows: primary color component conversion: TY1 = Fm ₂ y (M1) TM1 = Fm ₂ m (M1) TC1 = Fm ₂ c (M1) secondary color component conversion: TY2 = Fr ₂ y (M2) TM2 = Fr ₂ m (M2) TC2 = Fr ₂ c (M2) Third color component conversion: TY3 = Fk ₂ y (M3) TM3 = Fk ₂ m (M3) TC3 = Fk ₂ c (M3).

In step (305), it is determined whether or not the color classification is "3". If it is classification 3 (YES), the process proceeds to step (306), and if it is not classification 3 (NO), the process proceeds to step (307).

When the color classification is "3" in step (306), the primary to tertiary color components are converted by the following functional expression, and this processing is ended.

That is, each conversion amount can be expressed by a functional expression as follows: primary color component conversion: TY1 = Fm ₃ y (M1) TM1 = Fm ₃ m (M1) TC1 = Fm ₃ c (M1) secondary color component conversion: TY2 = Fb ₃ y (M2) TM2 = Fb ₃ m (M2) TC2 = Fb ₃ c (M2) Third color component conversion: TY3 = Fk ₃ y (M3) TM3 = Fk ₃ m (M3) TC3 = Fk ₃ c (M3).

In step (307), it is determined whether or not the color classification is "4". If it is classification 4 (YES), the process proceeds to step (308), and if it is not classification 4 (NO), the process proceeds to step (309).

In step (308), if the color classification is "4", the conversion of the primary to tertiary color components is performed by the functional expression shown below, and this processing is terminated.

That is, each conversion amount is expressed by a functional expression as follows: primary color component conversion: TY1 = Fc ₄ y (C1) TM1 = Fc ₄ m (C1) TC1 = Fc ₄ c (C1) secondary color component conversion: TY2 = Fb ₄ y (C2) TM2 = Fb ₄ m (C2) TC2 = Fb ₄ c (C2) Third color component conversion: TY3 = Fk ₄ y (C3) TM3 = Fk ₄ m (C3) TC3 = Fk ₄ c (C3).

In step (309), it is determined whether or not the color classification is "5". If it is classification 5 (YES), the process proceeds to step (310), and if it is not classification 5 (classification 6) (NO), the step (31).
Go to 1).

In step (310), when the color classification is "5", the conversion of the primary to tertiary color components is performed by the functional expression shown below, and this processing is ended.

That is, each conversion amount is expressed by a functional expression as follows: primary color component conversion: TY1 = Fc ₅ y (C1) TM1 = Fc ₅ m (C1) TC1 = Fc ₅ c (C1) secondary color component conversion: TY2 = Fg ₅ y (C2) TM2 = Fg ₅ m (C2) TC2 = Fg ₅ c (C2) Third color component conversion: TY3 = Fk ₅ y (C3) TM3 = Fk ₅ m (C3) TC3 = Fk ₅ c (C3).

In step (311), when the color classification is "6", the conversion of the primary to tertiary color components is performed by the functional expression shown below, and this processing ends.

That is, each conversion amount is expressed by a functional formula: primary color component conversion: TY1 = Fy ₆ y (Y1) TM1 = Fy ₆ m (Y1) TC1 = Fy ₆ c (Y1) secondary color component conversion: TY2 = Fg ₆ y (Y2) TM2 = Fg ₆ m (Y2) TC2 = Fg ₆ c (Y2) Third color component conversion: TY3 = Fk ₆ y (Y3) TM3 = Fk ₆ m (Y3) TC3 = Fk ₆ c (Y3).

Regarding the fifth step of the present invention, that is, the converted M-order color component is added for each N color signal to obtain a color image signal in which only the colors of the designated color section are color-corrected. Details of the step to be obtained will be described with reference to FIG. 6 corresponding to the step (400) described above.

In the processing shown in FIG. 6, the converted primary, secondary, and tertiary color components are added for each Y, M, and C signal, and the signal level TY of the new color-corrected Y, M, and C signals, Seeking TM, YC.

In step (401), the electronic computer performs a negative overflow prevention process for the Y signal conversion amounts TY1, TY2, and TY3. That is, if the conversion amounts TY1, TY2, TY3 are negative, they are set to zero.

In step (402), the signal level TY of the Y signal after color correction is obtained. That is, the conversion amounts of the primary, secondary, and tertiary color components are summed.

TY = TY1 + TY2 + TY3 In step (403), determine whether the signal level TY after color correction is higher than the maximum signal level LMX (fixed value = ²⁶ ) handled, and if it is higher (YES), step (4
04), if not big (NO), go to step (40
Go to 5).

In step (404), overflow prevention processing of the signal level TY after color correction is performed. That is, the signal level TY
Is the maximum signal level LMX.

In step (405), the conversion amount of the M signal TM1, TM2, T
Performs negative overflow prevention processing for M3. That is, if the conversion amounts TM1, TM2, and TM3 are negative, they are set to zero.

In step (406), the signal level TM of the M signal after color correction is obtained. That is, the conversion amounts of the primary, secondary, and tertiary color components are summed.

TM = TM1 + TM2 + TM3 In step (407), it is judged whether the signal level TM after color correction is larger than the maximum signal level LMX handled, and if it is larger (YES), the process proceeds to step (408). NO) go to step (409).

In step (408), overflow prevention processing of the signal level TM after color correction is performed. That is, the signal level TM
Is the maximum signal level LMX.

In step (409), the conversion amount T of the C signal after color correction
Performs negative overflow prevention processing for C1, TC2, and TC3. That is, if the conversion amounts TC1, TC2, and TC3 are negative, they are set to zero.

In step (410), the signal level TC of the C signal after color correction is obtained. That is, the conversion amounts of the primary, secondary, and tertiary color components are summed.

TC = TC1 + TC2 + TC3 In step (411), it is determined whether the signal level TC after color correction is larger than the maximum signal level LMX handled. If it is larger (YES), proceed to step (412). NO) ends this process.

In step (412), overflow prevention processing of the signal level TC after color correction is performed. That is, the signal level TC
Is the maximum signal level LMX. Then, this process ends.

Next, the principle of the above-described embodiment of the present invention will be described.

7 (a) to 7 (f) are explanatory views showing color divisions of pixels of a color image signal processed in one embodiment of the present invention, in which the horizontal axis represents the types of Y, M, C signals and the vertical axis. The axis indicates the signal level, and IY, IM, and IC indicate the signal levels of the Y, M, and C signals.

Generally, a color image recording apparatus such as a color printer or a color copy reproduces a full color from limited primary color signals of 3 to 4 colors. For example, as the three primary color signals, Y (yellow), M (magenta), which are the same as the three primary colors of printing,
There is C (cyan).

All of the colors represented by these three primary colors are shown in FIG. 7A to FIG. 7A when focusing on the magnitude relationship of the signal levels of the Y, M, and C signals.
It can be classified as shown in (f).

Therefore, the color classification can be determined as follows.

Category 1: IY> IM ≧ IC Category 2: IM ≧ IY> IC Category 3: IM> IC ≧ IY Category 4: IC ≧ IM ≧ IY Category 5: IC>IY> IM Category 6: IY ≧ IC> IM Also, Focusing on the difference in the signal levels of the Y, M, and C signals,
It can be classified into a primary color component, a secondary color component and a tertiary color component. The primary color component is the difference between the signal having the highest level and the second signal among the Y, M, and C signals, and the secondary color component is the difference between the second signal and the third signal in the level. Three
The next color component is the third level signal.

Generally, when there are N primary colors, they can be classified into 1, 2, ..., N-order color components. That is, n (n = 1, 2,
, N−1) The next-order color component is the difference between the n-th level signal and the n + 1-th level signal of the N-color signals, and the N-th order color component is the N-th level signal.

Now, as shown in FIG. 7 (a), in section 1,
The Y signal having the highest level among the Y, M, and C signals is divided into a primary color component Y1, a secondary color component Y2, and a tertiary color component Y3. The M signal having the second level is divided into a secondary color component M2 (= Y2) and a tertiary color component M3 (= Y3). The C signal, which is the third level signal, is the third-order color component
It is C3 (= Y3 = M3).

Therefore, the primary to tertiary color components in Category 1 can be determined as follows.

The primary color component: Y1 = IY-IM, the secondary color component: Y2 = IM-IC, the tertiary color component: Y3 = IC, the color categories 2 to 6 can be similarly defined.

FIG. 8 is an explanatory diagram showing the relationship between the color categories and hues processed in one embodiment of the present invention. Color categories 1 to 6 correspond to six divisions of a circle whose circumferential direction represents hue. is doing.

For example, Category 1 corresponds to yellow to red, Category 2 corresponds to red to purple, Category 3 corresponds to purple to blue, Category 4 corresponds to blue to turquoise, Category 5 corresponds to turquoise to green, and Category 6 corresponds to green to yellow. ing.

By the way, FIGS. 9A to 9C show the range in which the color changes when "Y", "M", and "C" are designated as the colors to be color-corrected in the embodiment of the present invention. FIG.

As shown in FIG. 9 (a), "Y" is set as the color to be color-corrected.
Is specified, the function Fy ₁ with the primary color component Y1 as a variable
Based on y, Fy ₁ m, Fy ₁ c, Fy ₆ y, Fy ₆ m, Fy ₆ c, the color segments that can be changed are “1” and “6”. That is, it is the range from green to yellow to red indicated by the shaded area.

As shown in FIG. 9B, "M" is set as the color to be color-corrected.
Is specified, the function Fm ₂ with the primary color component M1 as a variable
Based on y, Fm ₂ m, Fm ₂ c, Fm ₃ y, Fm ₃ m, Fm ₃ c, the color categories that can be changed are “2” and “3”. That is, it is the range from red to purple to blue shown by the shaded area.

As shown in FIG. 9 (c), "C" is set as the color to be color-corrected.
Is specified, a function Fc ₄ with the primary color component C1 as a variable
Based on y, Fc ₄ m, Fc ₄ c, Fc ₅ y, Fc ₅ m, and Fc ₅ c, the color segments that can be changed are “4” and “5”. That is, it is a range from blue to blue green to green indicated by the shaded portion.

Further, FIGS. 10A to 10C show a range in which the color changes when "R", "G", and "B" are designated as the colors to be color-corrected in the embodiment of the present invention. FIG.

As shown in Fig. 10 (a), "R" is selected as the color to be corrected.
Is specified, the function Fr ₁ y, Fr ₁ m, Fr ₁ c or Fr ₂ y, Fr ₂ m, Fr ₂ c having the secondary color component Y2 or M2 as a variable is specified.
Based on the, the color categories that can be changed are "1" and "2". That is, it is in the range of yellow to red to purple indicated by the shaded area.

As shown in Fig. 10 (b), "G" is the color to be corrected.
Is specified, a function Fg ₅ y, Fg ₅ m, Fg ₅ c or Fg ₆ y, Fg ₆ m, Fg ₆ m, Fg ₆ c having the secondary color component C2 or Y2 as a variable
Based on, the different color categories that can be changed are "5" and "6". That is, it is a range of blue-green to green to yellow indicated by the shaded area.

As shown in Fig. 10 (c), "B" is the color to be color-corrected.
Is specified, the function Fb ₃ y, Fb ₃ m, Fb ₃ c or Fb ₄ y, Fb ₄ m, Fb ₄ m, Fb ₄ c having the secondary color component M2 or C2 as a variable
Based on, the color categories that can be changed are "3" and "4". That is, it is a range from purple to blue to blue-green indicated by the shaded area.

If "K" is specified as the color to be corrected, 3
Functions Fk ₁ y, Fk having next color component Y3, M3 or C3 as variables
_{Based on 1} m, Fk ₁ c to Fk ₆ y, Fk ₆ m, Fk ₆ c, the color categories that can be changed are all “1” and “6”. That is, an achromatic color such as gray can be changed.

After this, the color classification is designated.

By the way, there are various ways of defining the above-mentioned functions Fy ₁ y, Fy ₁ m, Fy ₁ c, etc., such as a quadratic function and an exponential function. For example, when a function that is a constant multiple of a variable (linear conversion) is specified. This will be described with reference to FIGS. 11, 12, and 13.

11 (a) to 11 (c), "Y" is designated as the color to be color-corrected in the embodiment of the present invention, "1" is designated as the color classification, and a function which is a constant multiple of the variable is designated. FIG. 7 is an explanatory diagram showing Y, M, and C signals before and after color correction in the case.

FIG. 11 (a) shows Category 1 which varies depending on the functions Fy ₁ y, Fy ₁ m and Fy ₁ c.

Now, the functions Fy ₁ y, Fy ₁ m, and Fy ₁ c are TY1 = Fy ₁ y (Y1) = 2/3 * Y1 TM1 = Fy ₁ m (Y1) = 1/3 * Y1 TC1 = Fy ₁ c ( When Y1) = 1/3 * Y1 is specified, the conversion amount of Y, M, C signals TY1, TM1, TC
1 is set.

FIGS. 11 (b) and 11 (c) show the signal levels IY, IM, and IC of the Y, M, and C signals of category 1 before color correction and the signal levels TY, TM, and TC after color correction. There is. Secondary color components Y2, M2, 3
The next color components Y3, M3, C3 are saved as they are, and the primary color components
Only the conversion amount TY1, TM1, TC1 by Y1 changes, Y, M,
The balance of the entire C signal changes. In addition, the above-mentioned Category 1
Signals other than Y, M, and C do not change.

12 (a) to 12 (c), "R" is designated as the color to be color-corrected in the embodiment of the present invention, "1" is designated as the color classification, and a function which is a constant multiple of the variable is designated. FIG. 7 is an explanatory diagram showing Y, M, and C signals before and after color correction in the case.

FIG. 12 (a) shows Category 1 which changes depending on the functions Fr ₁ y, Fr ₁ m and Fr ₁ c.

Now, the functions Fr ₁ y, Fr ₁ m and Fr ₁ c are TY2 = Fr ₁ y (Y2) = 2/3 * Y2 TM2 = Fr ₁ m (Y2) = 4/3 * Y2 TC2 = Fr ₁ c ( If Y2) = 1/3 * Y2 is specified, the conversion amount of Y, M, C signals TY2, TM2, TC
2 is set.

12 (b) and 12 (c) show the signal levels IY, IM, and IC of the Y, M, and C signals of category 1 before color correction and the signal levels TY, TM, and TC after color correction. . The primary color component Y1, the tertiary color components Y3, M3, and C3 are stored as they are, and only the conversion amounts TY2, TM2, and TC2 by the secondary color component Y2 change, and the overall balance of the Y, M, and C signals changes. . It should be noted that the Y, M, and C signals other than the above-mentioned Category 1 do not change.

13 (a) to 13 (c), "K" is designated as the color to be color-corrected in the embodiment of the present invention, "1" is designated as the color classification, and a function which is a constant multiple of the variable is designated. FIG. 7 is an explanatory diagram showing Y, M, and C signals before and after color correction in the case.

FIG. 13 (a) shows a function Fk in which the tertiary color component Y3 is used as a variable.
Section 1 in which the signal level changes due to ₁ y, Fk ₁ m, and Fk ₁ c is shown by hatching.

Now, the functions Fk ₁ y, Fk ₁ m, and Fk ₁ c are TY3 = Fk ₁ y (Y3) = 1/2 * Y3 TM3 = Fk ₁ m (Y3) = 1/2 * Y3 TC3 = Fk ₁ c ( Y3) = 1/2 * Y3 is specified, Y, M, C signal conversion amount TY3, TM3, TC
3 is set.

FIGS. 13 (b) and 13 (c) show the signal levels IY, IM, and IC of the Y, M, and C signals of category 1 before color correction and the signal levels TY, TM, and TC after color correction. . The primary color components Y1 and the secondary color components Y2 and M2 are stored as they are, and only the conversion amounts TY3, TM3 and TC3 by the tertiary color component Y3 change, and the balance of the Y, M and C signals as a whole changes. In addition, Y other than the above-mentioned Category 1,
The M and C signals do not change.

Here, the configuration of the color image recording apparatus using the above-described embodiment will be described with reference to FIGS. 14 and 15.

FIG. 14 is a block diagram showing a color image recording apparatus using an embodiment of the present invention, and FIG. 15 is a block diagram showing a color correction circuit of a color image recording apparatus using an embodiment of the present invention.

Referring to FIG. 14, a color image recording apparatus includes a microprocessor (2) including an image memory having a capacity for one image and a memory for storing information regarding color correction, and the microprocessor (2) via a bus. And an operation input / output device (1A) composed of a display device such as a liquid crystal and a plurality of operation keys, an external interface (6) also connected to the microprocessor (2), and a microprocessor (2). Color correction circuit (7) connected to
And a head drive circuit (8) also connected to the microprocessor (2) and a print head (9) connected to the head drive circuit (8).

In FIG. 15, the color correction circuit (7) of the color image recording apparatus is a ROM (Read Only) whose input side and output side are connected to the microprocessor (2) via the above-mentioned bus.
Memory) (71), a ROM (72) similarly connected, and a ROM (73) similarly connected.

Next, the operation of the above-mentioned color image recording apparatus will be described.

Achieving all of the processing for color-correcting the Y, M, and C signals with only the arithmetic circuit and mounting the color-correcting circuit in the color image recording apparatus is not limited to the processing speed, the circuit scale, and the degree of freedom of the color correction function type. It is often inconvenient from the above point.

Therefore, the color image recording apparatus described above obtains color-corrected data for a large number (for example, ²⁶ types) of color correction functions that can be designated by the user in advance, writes the color-corrected data in the ROM, and performs the above-described operation during the printing operation. The method of reading the data is used.

First of all, information about the color you want to color correct is
It is input interactively using the operation input / output device (1A).

Hereinafter, a question (represented by "") displayed on the liquid crystal display unit of the operation input / output operation (1A) and a response (represented by "") input by the operation key by the user will be illustrated.

"Please select and enter the color you want to correct from the following.

"Y, M, C, R, G, B, K""Y""Category 1: yellow to red, category 6: green to yellow. Please enter the color category you want to correct.""1""The amount of Y, M, C can be changed with the following function formula for the amount of Y1.

TY1 = YY * Y1 TM1 = YM * Y1 TC1 = YC * Y1 "" Please input the function YY, YM, YC. "" 2/3, 1/3, 1/3 "" As shown in the graph, Y , M, C change. Are you sure? (YorN) "" Y "In the question above, and in Fig. 9 (a),
The graphs of FIG. 11 (b) and FIG. 11 (c) are displayed simultaneously.

Thus, information regarding color correction such as the example described above,
That is, a function for designating a color to be color-corrected and a hue to be converted is input by the user and stored in the memory by the microprocessor (2). The user is assumed to have some knowledge about colors and color printing.

On the other hand, the Y signal, M signal and C signal composed of 8 bits are input from the outside by the external interface (6) and stored in the image memory by the microprocessor (2).

Then, the function YY (= 2 /
3), YM (= 1/3), and YC (= 1/3) are converted by the microprocessor (2) into a Y function specification number, M function specification number, and C function specification number, which are composed of 6 bits. And is supplied to the color correction circuit (7). Similarly, the Y signal, the M signal, and the C signal stored in the above-mentioned image memory are converted into the Y signal IY, the M signal IM, and the C signal IC, which are configured by 6 bits, and are converted by the color correction circuit (7). Supplied.

Then, the Y signals TY and M which are color-corrected and configured by 6 bits are used.
The signal TM and the C signal TC are supplied to the head drive circuit (8) by the color correction circuit (7) and printed by the print head (9).

That is, the above-described color correction uses the 6-bit function designation number and the 6-bit signals IY, IM, and IC as address inputs,
Pre-stored 6-bit color-corrected signals TY and T
This is realized by reading M and TC from the ROMs (71), (72) and (73) as data.

In the color image recording apparatus described above, the Y (Y), M (M), and C (C) signals of the input (before color correction) and output (after color correction) of the color correction circuit are 6 bits. All you have to do is increase.

According to one embodiment of the present invention, the signal level conversion for each primary to tertiary color component is continuously changed without changing the signal level of the unspecified color section, and only the signal level of the specified color section is continuously changed. So you can output whatever color you want,
The effect is that subtle color reproduction can be realized.

Further, in the above-described embodiment, the case where three colors of Y, M, and C are shown as the input color image signals, but even in the case of four colors in which black is added to them, a function using the quaternary color component as a variable is shown. It goes without saying that the intended purpose can be achieved by adding the designation of.

[Effect of the Invention] As described above, the present invention includes a step of designating a color segment to be color-corrected in a color image signal of N colors classified into N factorial color segments, A step of designating a function for determining a color change amount of a color segment to be corrected, and an M (= 1, 2, 3, ..., N) next color component corresponding to the color segment from the input color image signal And a step of converting the M-th order color component based on the function, and adding the converted M-th order color component for each color signal of N colors to obtain only the colors of the designated color section. And the step of obtaining the color-corrected color image signal, the effect that the user can change only the color of the color segment desired to be changed to a desired delicate color.

[Brief description of drawings]

FIG. 1 is a flow chart showing one embodiment of the present invention, FIG. 2 is a flow chart showing one embodiment of the present invention, FIG. 3 is a flow chart showing one embodiment of the present invention, and FIG. FIG. 5 is a flowchart showing an embodiment of the invention, FIG. 5 is a flowchart showing an embodiment of the invention, FIG. 6 is a flowchart showing an embodiment of the invention, and FIGS. 7 (a) to 7 (f). FIG. 8 is an explanatory diagram showing color divisions of pixels of a color image signal processed in one embodiment of the present invention, and FIG. 8 is an explanatory diagram showing a relationship between color divisions and hues processed in one embodiment of the present invention, FIGS. 9 (a) to 9 (c) are explanatory views showing a range in which a color changes when "Y", "M", and "C" are designated as colors to be color-corrected in one embodiment of the present invention. FIGS. 10A to 10C show "R" and "G" as the colors to be color-corrected in the embodiment of the present invention. FIG. 11 (a) to FIG. 11 (c) are explanatory views showing a range in which the color changes when "B" is designated. In the embodiment of the present invention, "Y" is the color to be color-corrected and the color classification 1 and an explanatory view showing Y, M, and C signals before and after color correction when a function of a constant multiple of a variable is designated. FIGS. 12 (a) to 12 (c) show color correction in an embodiment of the present invention. Explanatory diagrams showing Y, M, and C signals before and after color correction when "R" as a desired color, color category 1, and a function that is a constant multiple of a variable are designated, FIGS. 13 (a) to 13 (c). ) Is an explanation showing Y, M, and C signals before and after color correction when "K" is designated as a color to be color-corrected in the embodiment of the present invention, color division 1, and a function of a constant multiple of a variable is specified. FIG. 14 is a block diagram showing a color image recording apparatus using an embodiment of the present invention, and FIG. 15 is a color correction circuit of a color image recording apparatus using an embodiment of the present invention. FIG. 16 is a block diagram showing a path, and FIG. 16 is a plan view showing a part of an operation panel of a color image recording apparatus using a conventional color correction method. In the figure, (1A) ... Operation input / output device, (2) ... Microprocessor, (6) ... External interface, (7) ... Color correction circuit, (8) ... Head drive circuit, (9) ...... Print head. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A step of designating a color segment to be color-corrected in a color image signal consisting of N colors classified into N factorial color segments, and a color change amount of the color segment to be color-corrected. A step of designating a function for determining the value of M (= 1, 2,
3, ..., N) Step of obtaining the next color component, step of converting the Mth color component based on the function, and addition of the converted Mth color component for each N color signal A color correction method comprising the step of obtaining a color-corrected color image signal only for the colors of the classified color.