JP2001061160A - Color correction device - Google Patents

Abstract

(57) Abstract: In a color correction device, it is an object to independently vary at least one of saturation and chromaticity. A hue axis generation circuit for generating signals of a plurality of hue axes for dividing a hue area into a plurality of parts, a hue area identification circuit for identifying an area, and hues orthogonal to two axes sandwiching an area to be corrected. Hue axis selection circuit 3 for selecting axes ODD and EVEN, and gain control circuits ODD4 and EVEN5 for varying gains of hue axes ODD and EVEN.
And a gain select circuit OD for selecting those gains
D6 and EVEN7, and the hue axis OD with variable gain
Gain conversion circuits ODD8, 9, 10 for converting D and EVEN signals into R-axis, G-axis, and B-axis components, and EVEN
The color correction can be performed by providing the control signal generation circuit 14, 11, 12, and 13 and switching the control of axis selection, gain selection, and gain conversion according to the area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color correction apparatus for a color video signal for realizing a high level of color reproducibility required for an image pickup apparatus for broadcasting or business use.

[0002]

2. Description of the Related Art As a conventional color image signal color correction apparatus, there is, for example, a 6-color independent color correction method. This six-color independent correction method uses the R color without changing the white balance.
(Red), Ma (magenta), B (blue), Cy (cyan),
G (green) and Ye (yellow) are independent of each other for the six colors,
It corrects saturation (color saturation) and chromaticity (hue). Specific examples include, for example, JP-A-3-27229.
No. 4 gazette.

Here, a conventional example of the six-color independent tone correction method will be described with reference to FIG. In FIG.
6, 57, 58 are arithmetic / comparators, 59 is a hue region determination circuit, 60 is a primary color component amount and complementary color component amount calculation circuit, 61 is a constant selection circuit, 62 and 63 are multipliers, and 64 and 65 are -1.
Double multiplier 66, data selection and addition circuit, 67, 68, 6
9 is an adder.

[0004] The operation of the conventional color correction apparatus configured as described above will be described with reference to FIGS.

First, color difference signals R-G, R-B, R-G, R-B,
The calculation of GB and the magnitude comparison are performed, and the result is supplied to the hue region determination circuit 59 and the calculation circuit 60 for the primary color component amount and the complementary color component amount. Therefore, the operation / comparators 56, 57, 5
Based on the calculation result of 8, the hue area determination circuit 59 first determines the hue area as shown in FIG.
FIG. 17 is a conceptual diagram of this hue area, which is divided into six hue areas based on a straight line from the center point in each color direction.

A circuit 60 for calculating the amount of primary color components and the amount of complementary color components compares the levels of the signals R, G, and B, and
As shown in FIG. 8, the maximum level, intermediate level, and minimum level are determined. Then, in the course of the comparison determination, a level difference between the maximum level and the intermediate level is obtained, and this is used as the primary color component amount. Further, a level difference between the intermediate level and the minimum level is obtained, and this is used as the complementary color component amount. Here, the color at the maximum level corresponds to the primary color, and the component at the minimum level corresponds to the white component. Then, the complementary color can be determined from the information of the color of the maximum level and the color of the minimum level. As a result, the primary color component and the complementary color component can be determined as shown in FIG.

In the example shown in FIG. 18, since the maximum level is R and the intermediate level is G, the primary color component is R and the complementary color components are R and G.
Ye (yellow) having an intermediate hue. The primary color component amount is RGB and the complementary color component amount is GB, and the level of the minimum level B is the white component amount.

The result of the hue region determination by the hue region determination circuit 59 is supplied to a constant selection circuit 61, and a specific gain constant is selected in accordance with the determination result. The correction is performed by multiplying the primary color component amount and the complementary color component amount calculated by the circuit 60, respectively. Therefore, a specific gain constant corresponding to each of the hue regions from region 1 to region 6 is set in the constant selection circuit 61 in advance.

The primary color component amount and the complementary color component amount multiplied by the gain constants by the multipliers 62 and 63 in this way are supplied to a data selection circuit 66 for selecting addition / subtraction and selecting connection for video signals R, G and B. On the one hand, and on the other hand via complementers (-1 times multipliers) 64, 65, respectively. Then, after an addition destination is selected by the data selection and addition circuit 66, the data is supplied to each of the adders 67, 68, and 69, and is added to the video signals R, G, and B.

Therefore, when the color tone of the signal R is corrected, for example, in the case of correction in the saturation direction, the primary color component amount RG is multiplied by a specific constant Kr and then added to the video signal R. At this time, if the ratio of the constant Kr is in the range of -1 to 1 times, even with this correction, the level difference between the intermediate level and the minimum level (complementary color component amount) and the minimum level amount (white component amount) It does not change.

Further, when correcting the saturation direction of the signal Ye, the complementary color component amount GB is multiplied by a specific constant Ky, and then R
And G, respectively. Also at this time, if the ratio of the constant Ky is in the range of -1 to 1 times, even with this correction, the level difference between the maximum level and the intermediate level (primary color component amount) and the minimum level amount (white component amount) Does not change.

Therefore, in this case, the constants Kr and Ky
By maintaining the white balance, the primary color R and the complementary color Y
The correction of the saturation direction of e can be performed independently. The same applies to other hues. In the above-described six-color independent tone correction method, the correction in the chromaticity direction can be similarly performed independently.

[0013]

However, in the above-mentioned conventional technique, R, Ma, B, Cy, G, and Ye are used.
It works well for colors that are close to color, but does not work well for those intermediate colors. For example, in the correction of a skin color or the like, which is an intermediate hue between R and Ye, a delicate difference in color tone is easily recognized because it is particularly likely to remain in human memory.
Therefore, accurate color tone correction is required in advance so as to obtain a skin-like color. However, since the color is an intermediate color, it is difficult to perform fine correction with the conventional technique, and correct skin color cannot be corrected.

FIG. 19 shows the gains in the saturation directions of R and Ye in the case where the correction near the skin color is performed by the conventional technique.
As can be seen from the above, it is possible to increase the gain of the skin color in the saturation direction by increasing the saturation direction gain of R and Ye, but it cannot be used in practice because it greatly affects the tone of R and Ye.

In addition, a technique has been proposed in which the above-mentioned conventional technique is developed to further divide six colors, and to correct an intermediate color by using a reference axis of the six colors and an auxiliary reference axis therebetween (for example, Japanese Patent Application Laid-Open No. 9-1997). 247701), a means for separating the color to be corrected into a reference axis and an auxiliary reference axis sandwiching the color to be corrected is required, and the circuit scale is increased, and it is difficult to perform the correction easily.

In broadcast and commercial use, the images of many television cameras are often switched and used by switchers, and it is very important that the color tone of each camera be the same. As with the sharpness of the luminance, it is important to adjust the colors in the same way to eliminate the discomfort of the switching image, such as the sharpness at the time of high saturation, but it is difficult to cope with the conventional technology.

As described above, the conventional color correction apparatus has the above-mentioned problems.

In view of the foregoing, the present invention divides the hue into fine colors not only in the reference colors but also in the intermediate colors, and further in the intermediate colors between the reference colors and the intermediate colors with a simple configuration without a large increase in the circuit scale. The purpose of the present invention is to provide a color correction device that can perform color correction independently of each other, and furthermore, by using this color correction device, it is possible to easily unify the color tone of a plurality of television cameras, and furthermore, at the time of high saturation. An object is to reduce the influence on sharpness.

[0019]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention generates a plurality of hue axes including axes of three primary color components and having axes orthogonal to the respective axes. A color correction device that performs color correction for each of the hue regions divided by the above, wherein a hue axis generation circuit generates a plurality of hue axis signals, and a hue region identification circuit identifies a hue region from the plurality of hue axis signals. When correcting the identified hue region, a hue axis selection circuit selects signals of two first and second hue axes orthogonal to two hue axes sandwiching the hue region, respectively, And the second gain varying means controls the gains of the signals of the first and second hue axes using the saturation correction gains in the respective correction regions. Further, the output signal of the first gain varying means is converted to the ratio of red, green, and blue components of an axis that is not orthogonal to the first hue axis among the two axes sandwiching the region for color correction by the first gain converting means. Similarly, the output signal of the second gain varying means is converted to the ratio of the red, green, and blue components of an axis that is not orthogonal to the second hue axis among the two axes sandwiching the region for performing color correction. The gain is converted by the second gain converting means, and the gain-converted signals in the R-axis direction, the G-axis direction, and the B-axis direction are added to the corresponding input signals, thereby correcting the saturation direction. It will be realized.

Thus, the saturation of each hue area can be independently corrected, and the hue area is finely divided,
Fine correction of the saturation of the intermediate color is also possible.

Further, according to the present invention, in order to correct chromaticity,
Of the two axes sandwiching the region for performing color correction on the output signal of the first gain varying means, the red, green, and blue components of the hue are moved in a direction perpendicular to the first hue axis in a direction perpendicular to the axis. The gain is converted by the first gain converting means for converting the gain into a ratio, and similarly, the output signal of the second gain changing means is not orthogonal to the second hue axis among the two axes sandwiching the color correction area. A second to convert the gain to a ratio of red, green and blue components that move the hue in a direction perpendicular to the axis relative to the axis
The chromaticity correction is realized by performing gain conversion by the gain conversion means of (1) and adding these gain-converted signals in the R-axis direction, the G-axis direction, and the B-axis direction to the corresponding input signals. .

Thus, the chromaticity of each hue region can be independently corrected, and the hue region is finely divided,
Fine correction of the chromaticity of the intermediate color is also possible.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a plurality of axes including axes of three primary color signals of red, green and blue on hue coordinates and having axes orthogonal to the respective axes. A hue axis generation circuit for generating signals of the plurality of hue axes from an input video signal, wherein the hue axis generation circuit generates a signal of the plurality of hue axes. A hue region identification circuit for identifying the corresponding hue region from a plurality of hue axis signals, and first and second hue axes respectively intersecting two hue axes sandwiching a hue region for performing color correction from the plurality of hue axis signals A hue axis selection circuit for selecting a signal of the hue axis, first and second gain variable means for respectively varying the gains of the first and second hue axis signals, and a first gain variable means. For the output signal, two that sandwich the area for color correction A first gain conversion unit that converts a gain into a ratio of red, green, and blue components on an axis that is not orthogonal to the first hue axis on the hue axis, and an output signal of the second gain variable unit. Is a second gain conversion unit that converts a gain into a ratio of red, green, and blue components of an axis that is not orthogonal to the second hue axis among two hue axes sandwiching a region where color correction is performed; An adding circuit for adding the respective outputs in the R-axis direction, the G-axis direction, and the B-axis direction from the gain converting means to the corresponding three primary color signals of the input video signal, and an identification signal from the hue area identification circuit; The hue axis selection circuit, the first and second gain variable means, and the first and second gain conversion means are controlled in accordance with each hue area to independently correct the saturation of each hue area. A control circuit, and the selected two axes First, second
Hue axes) as correction signals, these signals have the function of changing the on-axis gain of the two axes sandwiching each correction area, and can independently correct the saturation of each hue area. By finely dividing the hue region, fine correction of the saturation of the intermediate color is also possible.

According to a second aspect of the present invention, a plurality of hue axes including axes of three primary color signals of red, green, and blue and having axes perpendicular to the respective axes are generated on the hue coordinates. A hue axis generation circuit that generates a signal of the plurality of hue axes from an input video signal; and a hue axis generation circuit that generates a signal of the plurality of hue axes from an input video signal. A hue region identification circuit for identifying the corresponding hue region from a signal, and first and second hue axis signals orthogonal to two hue axes sandwiching the hue region for performing color correction from the plurality of hue axis signals. A hue axis selection circuit for selecting
The first and second gain varying means for varying the gains of the signals of the first and second hue axes, respectively, and the output signal of the first gain varying means sandwiching a region for performing color correction. First gain conversion means for converting a gain into a ratio of a red, green, and blue component that moves a hue in a direction perpendicular to an axis that is not orthogonal to the first hue axis, of the two hue axes; For the output signal of the second gain varying means, the hue is set in a direction perpendicular to the axis that is not orthogonal to the second hue axis, out of the two hue axes sandwiching the region for color correction. Second gain converting means for converting a gain into a ratio of moving red, green, and blue components; and outputting the respective outputs in the R-axis direction, the G-axis direction, and the B-axis direction from each of the gain converting means to the corresponding input. An addition circuit for adding to the three primary color signals of the video signal; A gain positive / negative determination circuit for determining whether each gain of the first and second gain variable means is positive or negative, and a hue axis selection circuit based on an identification signal from the hue region identification circuit and a determination signal of the gain positive / negative determination circuit. And a control circuit for controlling the first and second gain varying means and the first and second gain conversion means according to each hue area to independently correct the chromaticity of each hue area. The signals of the selected two axes (first and second hue axes) are used as correction signals, and these signals have the function of varying the gain in the direction perpendicular to the two axes sandwiching each correction region. By
The chromaticity of each hue region can be independently corrected, and fine correction of the chromaticity of an intermediate color is also possible by dividing the hue region into small parts.

The third aspect of the present invention is the first aspect of the present invention.
In the invention described above, in the first and second gain varying means, the correction gains before and after the hue axis are set to the same gain setting so that a saturation discontinuity does not occur on the hue axis dividing each hue region. As a result, it is possible to avoid a step in the correction of the saturation at the boundary of the hue region.

The invention described in claim 4 is the same as the invention described in claim 2.
In the invention described in the above, in the first and second gain variable means, the gain of correction before and after the hue axis is set to the same gain setting so that chromaticity discontinuity does not occur on the hue axis dividing each hue region. Accordingly, it is possible to avoid the occurrence of a step in the correction of the chromaticity at the boundary of the hue region.

According to a fifth aspect of the present invention, there is provided a color correction apparatus according to the first or third aspect and / or the color correction apparatus according to the second or fourth aspect, further comprising:
A reference color generation circuit for generating a reference color signal composed of three primary color signal components of blue; and an output signal of the reference color generation circuit and three primary color signal components of red, green, and blue obtained from an actual imaging subject. A switching circuit for switching the video signal to be configured and outputting to the color correction device; and the reference color based on an output signal of the gain conversion means of the color correction device to which an output signal from the switching circuit is input. A correction amount difference calculating circuit for calculating a difference between at least one of a saturation amount and a chromaticity correction amount between a case of an output signal of the generation circuit and a case of a video signal of an actual imaging subject; and an output of the correction amount difference calculation circuit. A comparison circuit that compares the signal with a signal of a predetermined reference level and provides an output corresponding to the difference, and controls a correction gain of the color correction device based on an output of the comparison circuit. Therefore, the correction amount (gain) of at least one of the saturation and the chromaticity can be set based on the signal of the reference level, whereby a plurality of devices including the color correction device of the present invention, for example, a plurality of In a television camera or the like, at least one of saturation and chromaticity, that is, unification of color tone can be realized.

[0028] The invention described in claim 6 is the same as the claim 1.
Or a color correction device based on at least one of the color correction device according to claim 3 and the color correction device according to claim 2 or 4, and a color difference signal generated based on the color corrected signal output from the color correction device; A chroma detail circuit for extracting a high frequency component of the signal and performing frequency correction at the time of a high chroma image, a gain constant for determining at least one of correction amounts of chroma and chromaticity in the color correction device, and a circuit of the chroma detail. A gain control circuit that controls a gain of the chroma detail circuit based on a chroma detail gain constant that determines a correction amount, whereby even when correction of at least one of saturation and chromaticity is performed, Chroma detail gain that corrects sharpness can be adjusted appropriately to reduce the effect on sharpness of high chroma images It is possible. According to a seventh aspect of the present invention, in the invention of the sixth aspect, the gain control circuit decreases the chroma detail gain when the saturation gain constant is positive, and increases the chroma detail gain when the saturation gain constant is negative. Control, so that
Chroma detail correction similar to the case where no saturation correction has been performed can be performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a color correction apparatus according to Embodiment 1 of the present invention.

The color correction apparatus of this embodiment generates a plurality of hue axes including axes of three primary color signals of red, green and blue and having axes orthogonal to the respective axes on hue coordinates. In FIG. 1, reference numeral 1 denotes a hue axis generation circuit for generating signals of a plurality of hue axes from an input video signal composed of three primary color signal components. Reference numeral 2 denotes a hue area identification circuit that identifies a hue area divided from the output signal of the hue axis generation circuit 1;
3 selects two axes orthogonal to the two axes sandwiching the region for performing color correction from the signal of the hue axis of the hue axis generation circuit 1,
A hue axis selection circuit for outputting a hue axis ODD as a hue axis and a hue axis EVEN as a second hue axis. Reference numerals 4 and 5 denote a hue axis ODD and a hue axis EV output from the hue axis selection circuit 3.
Gain control circuits ODD and EVEN for varying the gain of the EN signal are gain select circuits ODD and EVEN for switching and outputting gain constants to gain control circuits ODD4 and EVEN5. By the gain select circuit ODD and EVEN6,7,
First and second gain varying means for varying the gains of the signals of the first and second hue axes are configured.

8, 9 and 10 are gain control circuits O
R-axis direction for gain conversion of the output signal of DD4 to the ratio of red, green, and blue components of an axis that is not orthogonal to the hue axis ODD, which is the first hue axis, of the two axes for performing color correction;
G axis direction, B axis direction gain conversion circuit, similarly, 11,1
Reference numerals 2 and 13 denote gains of the output signal of the gain control circuit EVEN5 by the ratio of red, green, and blue components of an axis that is not orthogonal to the hue axis EVEN, which is the second hue axis, of the two axes for performing color correction. R axis direction to convert, G axis direction, B
Axial direction gain conversion circuit, R axis direction, G axis direction, B axis
Axial gain conversion circuits 8, 9, and 10 constitute first gain conversion means, and R, G, and B axis gain conversion circuits 11, 12, and 13 constitute second gain conversion means. You.

Reference numeral 14 denotes a control signal generation circuit as a control circuit for outputting a control signal to each circuit based on the output signal of the hue region identification circuit 2. Reference numerals 15, 16, and 17 denote input three primary color signals and R-axis and G-axis directions. B axis direction gain conversion circuit ODD8-10
And an adder for adding the correction signals output from EVEN11 to EVEN13.

The operation of the color correction apparatus according to the first embodiment configured as described above will be described below with reference to FIGS. In the following description, the areas in FIG. 2 to FIG. 5 and the like are described as areas 1, 2, 3,.

FIG. 2 shows six types of hue axes f1 to f1 on hue coordinates.
FIG. 3 is a conceptual diagram in a case where the image is divided into 12 areas at f6, FIG. 3 is a hue area discrimination table indicating the positive / negative correspondence between the divided hue areas and the hue axis signals, and FIG. FIG. 5 is an explanatory diagram for explaining how to select a gain in the gain selection circuits 6 and 7 and how to apply a gain.

The hue axis generation circuit 1 generates six hue axes f1 to f6 that divide the hue coordinates into 30-degree units and divide into twelve hue regions as shown in FIG. That is, their hue axes are given by the following arithmetic expressions from the R, G, and B input three primary color signals.

F1 = BG f2 = 2G- (R + B) f3 = GR f4 = 2R- (G + B) f5 = RB f6 = 2B- (R + G) Created by the hue axis generation circuit 1. The hue axes f1 to f6 are
The signals are input to the hue region identification circuit 2 and the hue axis selection circuit 3.

As shown in FIG. 3, the hue area identification circuit 2 identifies each hue area based on the sign of each hue axis signal corresponding to each of the areas 1 to 12, and controls the control signal generation circuit 14. The navel identification signal is output. The control signal generation circuit 14 converts the control signal into a hue axis selection circuit 3, a gain selection circuit ODD6 and a gain selection circuit EVEN7, an R axis direction gain conversion circuit ODD8, a G axis direction gain conversion circuit ODD9, in accordance with the input identification signal. B axis direction gain conversion circuit ODD10, R axis direction gain conversion circuit EVEN11, G axis direction gain conversion circuit EVEN12,
Output to the B-axis direction gain conversion circuit EVEN13.

The hue axis selection circuit 3 includes a control signal generation circuit 4
With respect to the two signals sandwiching the region for performing color correction, two axes orthogonal to each axis are selected and output based on the output signal.

For example, when the area 1 is corrected as shown in FIG. 4, the two axes sandwiching the area 1 are f1 and f2, and f
Since two axes orthogonal to 1 and f2 are f4 and f5,
The hue axis f5 is selected as the first hue axis ODD output from the hue axis selection circuit 3, and the f4 is selected and output as the second hue axis EVEN.

After that, the signal of the hue axis ODD is multiplied by a predetermined gain constant by the gain signal output from the gain selection circuit ODD6 by the gain control circuit 4, and the R axis direction gain conversion circuit ODD8 and the G axis direction gain conversion circuit ODD9. , B-axis direction gain conversion circuit ODD10
Is output to Each gain conversion circuit ODD converts the input signal of the hue axis ODD into the R, G, B of the hue axis f1 (that is, the axis that is not orthogonal to the first hue axis ODD among the two axes sandwiching the hue region 1). The gain is converted to a ratio and output to the corresponding adder circuits 15, 16, and 17. In this case,
Since f1 is R: G: B = 1: 0: 2, R: G: B =
The gain is converted to a ratio of 1: 0: 2 and output. When this signal is added, the gain in the upward direction of the f1 axis is changed.

Similarly, the signal of the hue axis EVEN is supplied from the gain control circuit 5 to the gain select circuit EVEN7.
Are multiplied by a predetermined gain constant by the gain signal output from the first and second gain conversion circuits, and output to the R-axis direction gain conversion circuit EVEN11, the G-axis direction gain conversion circuit EVEN12, and the B-axis direction gain conversion circuit EVEN13. Each gain conversion circuit EVEN converts the input signal of the hue axis EVEN into the R, G, and B signals of the hue axis f2 (that is, the axis that is not orthogonal to the second hue axis EVEN among the two axes sandwiching the hue region 1). The gain is converted to a ratio and output to the corresponding adders 15, 16 and 17. In this example, since f2 is R: G: B = 1: 0: 1, the gain is converted to a ratio of R: G: B = 1: 0: 1 and output. When this signal is added, the gain in the upward direction of the f2 axis is changed.

Each R-axis direction gain conversion circuit ODD8, G-axis direction gain conversion circuit ODD9, B-axis direction gain conversion circuit ODD10, and R-axis direction gain conversion circuit EVEN11,
As for the ratio of the gain conversion to the G-axis direction gain conversion circuit EVEN12 and the B-axis direction gain conversion circuit EVEN13, the control signal generation circuit 14 sets the above ratio corresponding to the area 1.

In this way, the two axes sandwiching the hue region 1
The signal components of the hue axis ODD (f5) and the hue axis EVEN (f4) are converted so as to change the on-axis gains of f1 and f2, and are added to the input three primary color signals by the adders 15, 16, and 17. Thus, the saturation of the hue region 1 is changed.

Here, how to select the gains of the gain select circuits ODD6 and EVEN7 will be described with reference to FIG.

FIG. 5 shows an example in which the saturation of the hue areas 1 and 2 is corrected. As described above, for the hue area 1, the hue axis ODD output from the hue axis selection circuit 3 is f5, and the hue axis EVEN is f4. Similarly, for the hue region 2, the first hue axis ODD is f
5. f6 is selected as the second hue axis EVEN. The gain select circuit ODD6 selects the gain constant AG1 in the area 1 and the gain constant AG3 in the area 2 by the control signal generation circuit 14. Also, the gain select circuit EV
EN7 selects gain constant AG2 in region 1 and gain constant AG2 also in region 2. In other words, the gain of correction near the boundary of the hue region is set to the same constant, thereby preventing a correction step from occurring at the boundary. That is, the gain constants corresponding to the hue axes f1 to f6 of the areas 1 to 6 are AG1 to AG
6, AG7 to AG12 are selected as gain constants corresponding to the hue axes f1 to f6 of the regions 7 to 12.

Further, since the hue axis f5 is a signal orthogonal to the hue axis f2, the hue axes f1 and f3 have the maximum level, and the hue axis f2 has the minimum (0) level. Therefore, the correction based on the hue axis f5 has no effect on the hue axis f2. Conversely, since the hue axis f4 is a signal orthogonal to the hue axis f1, the hue axis f2 has a maximum level and the hue axis f1 has a minimum level. The correction by the hue axis f4 has no effect on the hue axis f1. Further, since the hue axis f6 is a signal orthogonal to the hue axis f3, the hue axis f2 has a maximum level and the hue axis f3 has a minimum (0) level. Has no effect.

As shown in FIG. 5, the hue axes f1, f2, f3
When the amplitudes of the correction gains are illustrated on the axis of the graph, the amplitudes of the correction gains are as shown in a to c in the figure. By varying the gain constants AG1, AG2, and AG3, respectively,
In the hue region 2, the saturation in each region can be independently varied by adding b and c. The same applies to other hue regions.

As described above, according to the first embodiment of the present invention, not only colors close to the six colors of R, Ma, B, Cy, G, and Ye but also intermediate colors between the two colors can be used. Correction of the saturation that works effectively can be performed independently. In the case of the present embodiment, since the hue area is divided into 12 equal parts,
The ratio of the three primary color signals on each axis is R: G: B = 0: 0: 1,
R: G: B = 1: 0: 2, R: G: B = 1: 0: 1,
R: G: B = 2: 0: 1, R: G: B = 1: 0: 0, etc. (for example, hue regions 12, 1, 2, 3 and other regions are the same)
Since the ratio becomes simple, each R-axis direction gain conversion circuit OD
D8, G axis direction gain conversion circuit ODD9, B axis direction gain conversion circuit ODD10, and R axis direction gain conversion circuit EV
The EN11, the G-axis direction gain conversion circuit EVEN12, and the B-axis direction gain conversion circuit EVEN13 can be realized by simple circuits by bit shifting digital data without using a multiplier.

Further, as in the above-described conventional example, there is no need for a means for decomposing the color to be corrected into a reference axis and an auxiliary reference axis sandwiching the color to be corrected, and the circuit can be realized with a relatively simple circuit configuration.

Although not particularly described, rewriting and setting of the values of the gain constants AG1 to AG12 can be appropriately realized by means such as a microcomputer (not shown). (Embodiment 2) FIG. 6 shows Embodiment 2 of the present invention.
1 is a block diagram showing a configuration of a color correction device according to the first embodiment. 6, reference numeral 1 denotes a hue axis generation circuit, 2 denotes a hue region identification circuit, and 3 denotes hue axes ODD and E as first and second hue axes.
Hue axis selection circuits for selecting two axes of VEN, 4 and 5 are gain control circuits ODD and EVEN, and 6 and 7 are gain select circuits ODD and E for switching and outputting gain constants to gain control circuits ODD4 and EVEN5.
VEN, 15, 16, 17 are adders, 18, 19, 2
0, 21, 22, 23 are gain conversion circuits in the R-axis direction, G-axis direction, and B-axis direction; 25 is a gain polarity determination circuit that determines the polarity of the chromaticity gain given to the gain selection circuits ODD6 and EVEN7; This is a control signal generation circuit as a control circuit that outputs a control signal to each circuit based on output signals of the hue region identification circuit 2 and the gain positive / negative determination circuit 25. The same components as those shown in FIG. The reference numerals are used, and the description is omitted.

The difference of the first embodiment from FIG. 1 is that the gain conversion circuits ODD18, 1 in the R-axis direction, the G-axis direction, and the B-axis direction are different.
Reference numerals 9 and 20 denote the first hue axis ODD of the two axes for performing color correction on the output signal of the gain control circuit ODD4.
Is to perform gain conversion to the ratio of red, green, and blue components for moving the hue in a direction perpendicular to the axis that is not orthogonal to the axis. Similarly, gain conversion circuits EVEN21, 22, 23 in the R-axis direction, G-axis direction, and B-axis direction orthogonally intersect with the second hue axis EVEN of the two axes for performing color correction on the output signal of the gain control circuit EVEN5. Gain conversion is performed on the ratio of the red, green, and blue components that shifts the hue in a direction perpendicular to the axis with respect to the axis not performed. Further, a gain positive / negative determination circuit 25 for determining whether the gain is positive or negative is added to the chromaticity gain, and the control signal generation circuit 24 determines not only the output signal of the hue region identification circuit 2 but also the gain positive / negative determination. The point is that the control signal is output to each circuit by the output signal of the circuit 25.

While the first embodiment is a color correction device that varies the saturation, the second embodiment is a color correction device that varies the chromaticity.

The operation of the color correction apparatus according to the second embodiment configured as described above will be described below with reference to FIG.

FIG. 7 shows the hue axis f1 described in the first embodiment.
The second embodiment with respect to the hue area divided by f6
FIG. 4 is an explanatory diagram for explaining a state of correction in FIG. Consider a case in which each hue axis is moved in the direction indicated by the arrow in FIG.
Note that the gain constant is positive in the clockwise direction and negative in the counterclockwise direction in FIG. Also, the signs such as -f5, -f6, -f2 and the like in FIG. 7 indicate the sign of the hue axis in the correction area. For example, in the area 1, the hue axis f5 is shown in FIG. Similarly, in the region 2, the hue axis f6
Is positive as shown in FIG. Also, R, G, B
The sign of the ratio of the gain of the above indicates that the original ratio of the gain of R, G, B is multiplied by the sign of the hue axis and the sign of the clockwise and counterclockwise gain.

For example, as for the hue region 1, f5 is output from the hue axis selection circuit 3 as the first hue axis ODD and f4 is output as the second hue axis EVEN, as in the first embodiment. Thereafter, the signal of the hue axis ODD is supplied to the gain select circuit ODD4 by the gain control circuit ODD4.
6 is multiplied by a predetermined gain constant by the gain signal output from the gain signal 6, and is output to the R-axis direction gain conversion circuit ODD18, the G-axis direction gain conversion circuit ODD19, and the B-axis direction gain conversion circuit ODD20. Each gain conversion circuit O
DD outputs the input hue axis ODD signal to the hue axis f1.
(That is, the first hue axis O of the two axes sandwiching the hue region 1
R in the direction perpendicular to the axis)
The gain is converted to the ratio of G and B, and the corresponding adder circuit 15,
Output to 16 and 17.

In the case of this example, the original ratios of the R, G, and B gains in the direction (counterclockwise) perpendicular to the hue axis f1 are:
R: G: B = 1: 0: 0, the sign in the area 1 of the hue axis f5 used for correction is negative as shown in FIG. 3 described above, and the counterclockwise gain constant is Since it is negative, the final gain ratio of R, G, B is R:
Since G: B = 1: 0: 0, the R-axis direction gain conversion circuit ODD18, the G-axis direction gain conversion circuit ODD19, B
In the axial gain conversion circuit ODD20, R: G: B =
The gain is converted to a ratio of 1: 0: 0 and output. When the gain-converted signal is added to the input three primary color signals, the phase of the hue axis f1, that is, the chromaticity, is changed using the signal of the hue axis f5.

Similarly, the signal of the hue axis EVEN is supplied to the gain select circuit EVEN by the gain control circuit EVEN5.
The gain signal output from VEN7 is multiplied by a predetermined gain constant to obtain an R-axis direction gain conversion circuit EVEN2.
1. Output to the G-axis direction gain conversion circuit EVEN22 and the B-axis direction gain conversion circuit EVEN23. Each gain conversion circuit EVEN converts the input signal of the hue axis EVEN to a hue axis f2 (that is, an axis that is not orthogonal to the second hue axis EVEN of the two axes sandwiching the hue region 1). The gain is converted to the ratio of R, G, and B in the direction, and output to the corresponding adder circuits 15, 16, and 17.

In this example, the original R, G, B gain ratio in the direction (clockwise) perpendicular to the hue axis f2 is R: G: B = -1: 0: 1. The sign in the region 1 of the hue axis f4 used in the above is positive as shown in FIG. 3 and the clockwise gain constant is positive, so that the final gain of R, G, B The ratio is
Since R: G: B = -1: 0: 1, the R-axis direction gain conversion circuit EVEN21 and the G-axis direction gain conversion circuit EVEN2
2. In the B-axis direction gain conversion circuit EVEN23, R:
G: B = -1: 0: 1 gain conversion and output.
When the gain-converted signal is added to the input three primary color signals, the phase of the hue axis f2, that is, the chromaticity, is changed using the signal of the hue axis f4.

For example, when the hue axis f2 is moved in a counterclockwise direction perpendicular thereto, the original R, G,
The gain ratio of B is R: G: B = 1: 0: -1, and the sign in the area 2 of the hue axis f6 used for correction is positive as shown in FIG. , Since the counterclockwise gain constant is negative, the final R,
The ratio of the G and B gains is R: G: B = -1: 0: 1. In the R-axis direction gain conversion circuit EVEN21, G-axis direction gain conversion circuit EVEN22, and B-axis direction gain conversion circuit EVEN23, R: The gain is converted to a ratio of G: B = -1: 0: 1 and added to the input three primary color signals.

The hue axis f4 at the boundary between the hue regions 3 and 4
Is changed, the ratio of B and G to R of the correction signal is switched clockwise or counterclockwise. That is, clockwise rotation of the hue region 3 is represented by R: G: B =
-1: 0: -2, counterclockwise R: G: B = 1: 2: 0
It is.

That is, in the hue region 3, the hue axis f
4 is moved clockwise using the hue axis f6,
The original R, G, B gain ratio is R: G: B = 1:
0: 2, the sign in the area 3 of the hue axis f6 used for correction is negative as shown in FIG. 3 described above, and the clockwise gain constant is positive. , G, B gain ratio is R: G: B = −1: 0:
−2, whereas in the hue region 3, the hue axis f
4 is moved counterclockwise using the hue axis f6, the original gain ratio of R, G, B is R: G: B =
1: 2: 0, the area 3 of the hue axis f6 used for correction
Is negative as shown in FIG. 3 above, and the gain constant in the counterclockwise direction is negative.
The final R, G, B gain ratio is R: G: B =
Similarly, in the hue region 4, when the hue axis f4 is moved using the hue axis f2 in the hue region 4, clockwise rotation is R: G: B = -1: 0: -2, and Clockwise is R:
G: B = 1: 2: 0.

Therefore, when the hue axis f4 at the boundary between the hue regions 3 and 4 is moved, whether the clock is clockwise or counterclockwise, that is, depending on whether the gain is positive or negative, the gain of the gain conversion circuits 21 to 23 is changed. It is necessary to switch the ratio. For this reason, the gain polarity determination circuit 25 determines whether the gain is positive or negative, for example, if the hue axis is f4, PG4
The control signal generation circuit 24 switches the gains of the gain conversion circuits 21 to 23 by determining whether the gain is positive or negative.

The switching of the gain is performed in addition to the hue axis f4 at the boundary between the hue regions 3 and 4, the hue axis f2 at the boundary between the hue regions 7 and 8, and the hue axis f at the boundary between the hue regions 11 and 12.
6, that is, it is also necessary to move the hue axis of the primary color signal.

As in the first embodiment, the correction amounts of the two axes sandwiching the correction area become zero on the other axes. (Because the hue axis of the correction signal vertically intersects with the hue axis of the area to be corrected), the phase of each hue axis can be changed independently.

In order to maintain the continuity of the phase change, the gain constants of the gain select circuits ODD6 and EVEN7 are selected in the same manner as in the first embodiment near the boundary of the hue region. . For example, the setting of the gain constants of the correction signals f4 and f6 for the hue axis f2 is selected to be common. The same applies to other hue regions.

As described above, according to the second embodiment of the present invention, not only colors close to six colors of R, Ma, B, Cy, G, and Ye, but also intermediate colors between the two colors are used. Correction of effective chromaticity can be performed independently.

Also, in this embodiment, as in the first embodiment, since the hue area is divided into 12 equal parts, the ratio of the three primary color signals in the direction perpendicular to each hue axis becomes a simple ratio. Each R axis direction gain conversion circuit ODD18, G axis direction gain conversion circuit ODD19, B axis direction gain conversion circuit ODD20
And an R-axis direction gain conversion circuit EVEN21, a G-axis direction gain conversion circuit EVEN22, and a B-axis direction gain conversion circuit E
The VEN 23 can be realized by a simple circuit by bit shifting digital data without using a multiplier.

Although not particularly described, the rewriting and setting of the values of the gain constants PG1 to PG12 can be appropriately realized by means such as a microcomputer (not shown). In the first and second embodiments, the hue axis that divides the hue coordinate into twelve is selected. However, if there is a hue axis orthogonal to each hue axis, for example, a finer 24 or 36 division is used. It is needless to say that the same effect can be obtained in a finer hue region.

It is needless to say that the first and second embodiments can be combined to provide a color correction circuit for individually correcting the saturation and the chromaticity.

(Embodiment 3) FIG. 8 is a block diagram showing a configuration of a color correction apparatus according to Embodiment 3 of the present invention.

In FIG. 8, reference numeral 26 denotes a reference color signal generation circuit for generating reference signals of R, G and B primary color signals, and reference numeral 27 denotes a three primary color signal of an input video signal and a reference color signal generation circuit 26.
A switching circuit for switching the three primary color output signals of
This is a saturation and chromaticity correction circuit for performing the same saturation or chromaticity correction as in the first or second embodiment. The saturation and chromaticity correction device 28 and the addition circuits 31 to 33 perform the above-described operations. A color correction device combining the first or second embodiment is configured.

Reference numeral 29 denotes a signal input to the color correction device,
A correction amount difference calculating circuit for calculating a difference between the amount of color correction between the case of the reference color signal and the case of the input video signal obtained by actually capturing a color bar chart as a subject; The comparator circuit compares the correction level difference reference level, which is the reference level, with the output signal of the correction level difference calculation circuit 29, and provides an output corresponding to the difference.

The operation of the color correction apparatus of the third embodiment configured as described above will be described below with reference to FIGS.

FIG. 9 is a block diagram showing an example of the internal configuration of the correction amount difference calculation circuit 29 and the comparison circuit 30. FIG.
34 and 35 are delay flip-flops, 36 is an inverting gate, 37 and 38 are AND gates, 39 and 41 are subtractors, 40 is an absolute value circuit, and 42 is a gate circuit. FIG. 10 shows an example of a signal generated from the reference color signal generation circuit 26, and FIG. 11 is a signal waveform diagram of each part of the color correction device of FIG.

The reference signal generation circuit 26 generates, for example, the signals shown in FIG. This is a so-called color bar signal, and each of the three primary color signals RS, GS, and BS components is, as shown in FIG.
It switches between the 100% (75%) level and the 0% level.
Therefore, a signal having the reference phase of R, G, B, Ma, Cy, and Ye and a high saturation level is output. On the other hand, as the input video signal, a signal obtained by imaging a color bar chart having the same pattern as the reference signal is input.

These signals are switched by the switching circuit 27 by the switching signal. For example, as shown in FIG. 11A, the switching signal is a signal that repeats High and Low at t / 2, and when Low, the reference signal is H.
At the time of high, switching is performed so as to select an input signal. Next, the output signal of the switching circuit 27 is input to a saturation / chromaticity correction circuit 28, and a saturation or chromaticity correction signal is output.

In the case where only the saturation is corrected, for example, the correction signal output in the R signal period is, as shown in FIG. 11B, the reference signal period is RSC and the object period is R.
Output at C level. Originally, the level of the reference signal period having a high saturation level is largely output. This signal is output to the correction amount difference calculating circuit 29 and the adding circuits 31 to 33 at the next stage.

The correction amount difference calculating circuit 29 has, for example, a configuration as shown in FIG. 9. When the correction amount signal shown in FIG. 11B is input, the delay flip-flop 34
The clock input from the outside is enabled by the inverting gate 36 and the AND gate 37 during the period when the switching signal is low, and is disabled when the switching signal changes from low to high. Therefore, the RSC data is held at that moment. On the other hand, the delay flip-flop 35 enables the clock by the AND gate 38 during the period when the switching signal is High,
Outputs RC data. Therefore, the subtraction circuit 39 outputs a signal RCD obtained by subtracting the correction amount RC of the subject period from the correction amount RSC of the reference signal period during the period in which the correction signal of the subject period is output (the latter half of t / 2). Is done. The absolute value of this signal is taken by the next absolute value circuit 40, and is output as a correction amount difference signal as shown in FIG. In the comparison circuit 30, the subtraction circuit 41
A preset correction amount difference reference level RCDS is subtracted from the correction amount difference signal, an unnecessary portion is gated by the gate circuit 42, and a comparison signal shown in FIG. 11D is output. This correction amount difference comparison output is detected by a microcomputer (not shown) or the like, and the level is set to a constant value or zero.
The saturation gain of the saturation and chromaticity correction circuit 28, that is, FIG.
AG1 to AG12 are controlled. This allows
The saturation correction can be adjusted so that the correction amount is a certain amount based on the reference signal.

The chromaticity can be similarly adjusted. Needless to say, the same can be performed for colors of other hues.

It is needless to say that the correction amount difference may be calculated, for example, at a vertical scanning period (V) rate according to the processing of the microcomputer or the like.

As described above, in the color correction apparatus according to the third embodiment, the correction amount of the saturation or the chromaticity can be set to the correction amount set based on the reference signal. If the test chart is imaged, the color correction of a plurality of television cameras can be adjusted exactly the same.

(Embodiment 4) FIG. 12 is a block diagram showing a configuration of a color correction apparatus according to Embodiment 4 of the present invention.

In FIG. 12, reference numeral 43 denotes a saturation / chromaticity correction circuit for correcting saturation or chromaticity equivalent to that of the circuit described in the first or second embodiment, and an addition to the saturation / chromaticity correction circuit 43. The circuits 44, 45, and 46 constitute the color correction device according to the first or second embodiment. Reference numeral 47 denotes a chroma detail circuit for correcting the frequency at the time of high saturation, and reference numeral 48 denotes a gain control circuit for controlling the gain of the chroma detail circuit 47.

Embodiment 4 configured as described above
The operation of the color correction device will be described below with reference to FIGS.

FIG. 13 is a block diagram showing an example of the internal configuration of the chroma detail circuit 47. In FIG. 13, 49 is a Y, color difference matrix circuit, 50 to 52 are high-pass filters, 53 and 55 are adders, and 54 is a multiplier.

The saturation and chromaticity correction circuit 43 outputs a saturation or chromaticity correction signal according to a saturation or chromaticity gain setting set by a microcomputer (not shown) or the like. This signal is added to the input three primary color signals by the adders 44 to 45 to create a signal whose saturation or chromaticity has been corrected.

Further, as a correction of color reproducibility, N
There is a chroma detail circuit that performs frequency correction at the time of high saturation in order to prevent the constant luminance principle from being destroyed when converted to a TSC composite signal, and to prevent deterioration of high frequency at the time of high saturation. In a television camera or the like having the same, the color tone changes due to the saturation or chromaticity correction. Therefore, in order to pursue faithful color reproducibility, it is necessary to perform chroma detail processing in accordance with the change in color tone. As shown in FIG. 12, a color-corrected signal is input to the chroma detail circuit 47. The circuit configuration is natural. In this case, a problem occurs depending on how to correct saturation or chromaticity.

Hereinafter, this will be described. The internal configuration of the chroma detail circuit 47 is as shown in FIG. 13, and when a color-corrected signal is input, the Y, color difference matrix circuit 4
9, the luminance signal Y and the color difference signals <RY>, <GY
>, <BY> are output. <> Indicates a positive signal. These color difference signals are input to high-pass filters 50 to 52, and the high-frequency components of their outputs are input to an adder 53 and added. Further, the gain is adjusted by the multiplier 54 according to the gain control signal of the gain control circuit 48, added to the luminance signal Y by the adder 55, and the frequency-corrected luminance signal is output.

The operation of the chroma detail circuit 47 has been described above. Here, consider the case where the saturation is corrected as the color correction. Assuming that the R single-color signal shown in FIG. 14A is input (solid line indicates no saturation correction, dotted line indicates the case with saturation correction), the luminance signal becomes as shown in FIG. 14B. Since the color difference signal is a positive signal only, <RY
> Only, as shown in FIG. At this time, the output of the high-pass filter 50 is as shown in FIG. 7E when there is no saturation correction, and as shown in FIG. Further, these signals are output to the multiplier 54
When the gain control is performed and the luminance signal Y is added by the adder 55, the luminance signal subjected to the chroma detail correction shown in FIGS.

As can be seen from each signal waveform diagram of FIG.
When the saturation correction is performed, when the correction is positive, that is, when the saturation is increased, the dotted line portion is added, so that the color difference signal level increases and the chroma detail also increases. Therefore, when the correction amount is large, there is a problem that the chroma detail is excessively attached and the sharpness is too sharp, thereby deteriorating the image quality.
Therefore, in the color correction apparatus according to the fourth embodiment, the chroma or chromaticity gain and the chroma detail gain set by a microcomputer or the like (not shown) are input, and the chroma or chromaticity gain is determined by the value of the chroma or chromaticity gain. And a gain control circuit 48 for giving the adjusted chroma detail gain to the chroma detail circuit 47.

In this example, the gain is controlled so that the detail level indicated by the dotted line in FIG. 14D becomes the detail level in FIG. 14E. As a result, chroma detail correction with a gain setting substantially equal to the case where no saturation correction is performed can be performed.

In this embodiment, the chroma detail is corrected in accordance with the color tone even when the chroma and chromaticity are corrected. Chroma detail gain can be adjusted to an appropriate gain by adjusting the chroma detail gain appropriately.

As described above, in the color correction apparatus according to the fourth embodiment, it is possible to appropriately adjust the color tone and the chroma detail level in a television camera or the like having the saturation / chromaticity correction circuit and the chroma detail circuit. And good color reproducibility and sharpness can be realized.

Although the third and fourth embodiments are applied to the color correction device for correcting either the saturation or the chromaticity of the first or second embodiment, other embodiments of the present invention will be described. Alternatively, the first and second embodiments may be combined to be applied to a color correction device that performs color correction for both saturation and chromaticity.

In the third and fourth embodiments, the color correction apparatus according to the first and second embodiments is applied to the color correction apparatus according to the present invention. May be applied. For example, when applied to the conventional example of FIG. 15, the constant (gain) of the constant selection circuit 61 may be adjusted, or the gain of the chroma detail circuit may be controlled using this constant.

[0097]

As described above, according to the present invention, the hue coordinate is divided into a plurality of parts with a simple structure, and at least one of the saturation and the chromaticity of each of the divided hue regions is independently corrected. By finely dividing the hue region, it is possible to finely adjust at least one of the saturation and chromaticity of the intermediate color.

Further, by photographing the same test chart with a plurality of television cameras, it is possible to set at least one of the same saturation and / or chromaticity correction, thereby simplifying the color tone of each television camera. And accurately.

Further, it is possible to achieve both the color tone correction of at least one of the saturation and the chromaticity and the sharpness correction by the chroma detail correction. As described above, it is possible to provide a color correction device that can obtain the above-described effects in color correction and color reproducibility.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a color correction device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram in a case where a hue coordinate is divided into 12 by six kinds of hue axes.

FIG. 3 is a hue area discrimination table showing correspondence between each area of a divided hue area and a positive / negative hue axis signal.

FIG. 4 is an explanatory diagram illustrating an example of color correction according to the first embodiment.

FIG. 5 is an explanatory diagram for explaining how to select a gain and how to apply a gain;

FIG. 6 is a block diagram illustrating a configuration of a color correction device according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating chromaticity correction according to the second embodiment.

FIG. 8 is a block diagram illustrating a configuration of a color correction device according to a third embodiment of the present invention.

FIG. 9 is a block diagram illustrating an example of an internal configuration of a correction amount difference calculation circuit 29 and a comparison circuit 30.

FIG. 10 is a diagram showing an example of a signal generated from a reference color signal generation circuit 26;

FIG. 11 is a signal waveform diagram of a circuit of the color correction device according to the third embodiment.

FIG. 12 is a block diagram illustrating a configuration of a color correction device according to a fourth embodiment of the present invention.

FIG. 13 is a block diagram showing an example of an internal configuration of a chroma detail circuit 47.

FIG. 14 is a signal waveform diagram illustrating the operation of the chroma detail circuit 47.

FIG. 15 is a block diagram showing a configuration of a conventional color correction device.

FIG. 16 is an explanatory diagram of a hue region in the conventional color correction.

FIG. 17 is a conceptual diagram of a hue region in conventional color correction.

FIG. 18 is a diagram illustrating the principle of calculating primary color components and complementary color components in conventional color correction.

FIG. 19 is a diagram showing a correction characteristic according to the related art.

[Explanation of symbols]

1 hue axis generation circuit 2 hue area identification circuit 3 hue axis selection circuit 4, 5 gain control circuit ODD and gain control circuit EVEN 6, 7 gain selection circuit ODD and gain selection circuit EVEN 8, 18R axis direction gain conversion circuit ODD 9, 19G axis direction gain conversion circuit ODD 10, 20B axis direction gain conversion circuit ODD 11, 21R axis direction gain conversion circuit EVEN 12, 22G axis direction gain conversion circuit EVEN 13, 23B axis direction gain conversion circuit EVEN 14, 24 control signal generation circuit 15, 16, 17, 31, 32, 33, 44, 45, 4
6, 53, 55 adder 25 gain positive / negative determination circuit 26 reference color signal generation circuit 27 switching circuit 28, 43 saturation / chromaticity correction circuit 29 correction amount difference calculation circuit 30 comparison circuit 34, 35 delay flip-flop 36 inversion gate 37 , 38 AND gate 39, 41 Subtractor 40 Absolute value circuit 42 Gate circuit 47 Chroma detail circuit 48 Gain control circuit 49Y, Color difference matrix circuit 50, 51, 52 High pass filter 54 Multiplier

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C065 AA01 BB15 BB16 CC01 GG10 GG15 GG21 GG22 GG23 GG25 GG32 GG34 5C066 AA01 BA20 CA17 EA05 EB01 EC01 EC02 EE04 EF04 GA01 KA12 KC03 KD02 KD17 KE03 KE03 KE03 KE03 KG01 KG05

Claims (7)

[Claims] 1. A plurality of hue axes including axes of three primary color signals of red, green, and blue and having axes orthogonal to the respective axes are generated on hue coordinates, and divided by these hue axes. A color correction device that performs color correction for each hue region, comprising: a hue axis generation circuit configured to generate the plurality of hue axis signals from an input video signal; and identifying the corresponding hue region from the plurality of hue axis signals. A hue axis identification circuit, and a hue axis selection circuit that selects first and second hue axis signals orthogonal to two hue axes sandwiching a hue area for performing color correction from the plurality of hue axis signals, First and second gain varying means for varying the gains of the signals of the first and second hue axes, respectively, and an output signal of the first gain varying means sandwiching a region for performing color correction. Of the two hue axes, the first hue axis is directly A first gain conversion unit for converting a gain into a ratio of red, green, and blue components of a non-axis, and two hue axes sandwiching a region for performing color correction with respect to an output signal of the second gain variable unit. A second gain conversion unit that converts a gain into a ratio of red, green, and blue components of an axis that is not orthogonal to the second hue axis; an R-axis direction, a G-axis direction, An adding circuit for adding each output in the B-axis direction to the corresponding three primary color signals of the input video signal; and a hue axis selection circuit based on the identification signal from the hue region identification circuit. A control circuit for controlling the gain varying means and the first and second gain converting means according to each hue area to independently correct the saturation of each hue area. . 2. A plurality of hue axes including axes of three primary color signals of red, green, and blue and having axes orthogonal to the respective axes are generated on the hue coordinates, and are divided by these hue axes. A color correction device that performs color correction for each hue region, comprising: a hue axis generation circuit configured to generate the plurality of hue axis signals from an input video signal; and identifying the corresponding hue region from the plurality of hue axis signals. A hue axis identification circuit, and a hue axis selection circuit that selects first and second hue axis signals orthogonal to two hue axes sandwiching a hue area for performing color correction from the plurality of hue axis signals, First and second gain varying means for varying the gains of the signals of the first and second hue axes, respectively, and an output signal of the first gain varying means sandwiching a region for performing color correction. Of the two hue axes, the first hue axis is directly A first gain conversion unit that converts a gain into a ratio of red, green, and blue components that shifts a hue in a direction perpendicular to the axis with respect to a non-axis, and an output signal of the second gain variable unit, Of the two hue axes sandwiching the region for performing color correction, an axis that is not orthogonal to the second hue axis and that shifts the hue in a direction perpendicular to that axis and that converts the gain into a ratio of red, green, and blue components. 2 gain conversion means; an addition circuit for adding respective outputs in the R-axis direction, G-axis direction, and B-axis direction from each of the gain conversion means to the corresponding three primary color signals of the input video signal; A gain positive / negative determining circuit for determining whether each gain of the second gain variable means is positive or negative; a hue axis selecting circuit based on an identification signal from the hue region identifying circuit and a determination signal of the gain positive / negative determining circuit; 1st, 2nd Gain varying means and the first and the second gain conversion means, color correction apparatus, characterized in that it comprises a control circuit for correcting independently chromaticity of each color region is controlled according to each hue region. 3. In the first and second gain varying means, the correction gains before and after the hue axis are set to the same gain so as to prevent discontinuity of saturation on a hue axis dividing each hue area. The color correction device according to claim 1. 4. In the first and second gain varying means, the correction gains before and after the hue axis are set to the same gain so that chromaticity discontinuity does not occur on the hue axis dividing each hue area. 3. The color correction device according to claim 2, wherein 5. A color correction device according to claim 1 or 3 and at least one of the color correction devices according to claim 2 or 4, and a reference color comprising three primary color signal components of red, green and blue. A reference color generation circuit for generating a signal; and a color correction device for switching between an output signal of the reference color generation circuit and a video signal composed of three primary color signal components of red, green, and blue obtained from an actual imaging subject. A switching circuit that outputs an output signal of the reference color generation circuit based on an output signal of the gain conversion unit of the color correction device to which an output signal from the switching circuit is input. A correction amount difference calculation circuit that calculates a difference between at least one of the saturation amount and the chromaticity correction amount in the case of a video signal; and an output signal of the correction amount difference calculation circuit and a signal of a predetermined reference level. Comparison and a comparator circuit for providing an output corresponding to the difference, based on an output of the comparator circuit, a color correction apparatus and controls the correction gain of the color correction device. 6. A color correction apparatus according to claim 1 or 3, and at least one of the color correction apparatuses according to claim 2 or 4, and a color difference based on a color-corrected signal output from the color correction apparatus. A chroma detail circuit for generating a signal and extracting a high-frequency component of the color difference signal to perform frequency correction at the time of a high-saturation image; and a gain for determining a correction amount of at least one of saturation and chromaticity in the color correction device. A color correction apparatus comprising: a gain control circuit that controls a gain of the chroma detail circuit based on a constant and a chroma detail gain constant that determines a correction amount of the chroma detail circuit. 7. The color correction device according to claim 6, wherein the gain control circuit controls to decrease the chroma detail gain when the saturation gain constant is positive, and increase the chroma detail gain when the saturation gain constant is negative.