JP2000299875A - Video signal processor and image pickup unit provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an image pickup unit to freely and accurately adjust image quality of a color area desired to be adjusted. SOLUTION: A hue discrimination section 5 of this image pickup unit discriminates a hue. A coefficient control section 6 selects various coefficients in a coefficient generating section 7 in response to a hue discriminated by the hue discrimination section 5. A chrominance signal processing section 4 and a luminance signal processing section 3 uses the various coefficients selected by the coefficient control section 6 to conduct various correction such as color reproduction correction and gamma correction. Thus, each color can more beautifully be reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus such as a video camera, and more particularly to a video signal processing apparatus which reproduces each color more beautifully by setting an optimum processing characteristic according to a hue.

[0002]

2. Description of the Related Art In general, video signals handled by an image pickup apparatus such as a color video camera are subjected to various signal processes such as gamma correction, contour correction, white balance adjustment, color gain adjustment, and hue adjustment.

For example, in the case of a color video camera, CC
In an imaging signal processing circuit that forms and outputs a luminance signal and a color signal from an imaging signal obtained by an imaging unit using a D image sensor or the like, the above-described gamma correction, contour correction, white balance adjustment, color gain adjustment, hue adjustment, etc. Is performed. In a digital signal processing camera that digitizes an image pickup signal, performs digital processing, and outputs the digital signal, an EEP
Various signal processing units are provided for performing the above-described gamma correction, contour correction, white balance adjustment, color gain adjustment, hue adjustment, and the like based on control parameters written in a nonvolatile memory such as a ROM.

In a color video camera, a flesh-colored portion of an image is detected, contour enhancement processing is performed to reduce the amount of detail in the portion, and frequency characteristics are reduced to blur wrinkles and stains on the face. , So that human skin is beautifully reproduced. However, in the above-described outline emphasis processing, only the frequency characteristic is changed, so that it is not possible to change the hue of the flesh color, and it is not possible to make the face color look beautiful or to slightly change the flesh color. As a method for solving this problem, a method described in Japanese Patent Application Laid-Open No. 6-141337 has been proposed. The digital signal processing camera described in this publication detects a specific color (for example, flesh color) portion of a captured image and changes the hue and luminance of the portion to reproduce the specific color more beautifully. ing.

FIG. 17 is a block diagram showing an example of a configuration of a main part of a conventional color video camera. In this figure, the imaging signal from the imaging element 81 is a low-pass filter (L
The luminance signal is input to a PF (82), and the luminance signal is extracted. The luminance signal is sent to an encoder 94 via a luminance signal gain adjustment circuit 83 and a luminance signal gamma correction circuit 84. Further, the image pickup signal from the image pickup device 81 is sent to the color separation circuit 85, and R,
The G and B signals are separated. The separated R, G, and B signals are sent to an R signal gain adjustment circuit 86, a G signal gain adjustment circuit 87, and a B signal gain adjustment circuit 88, respectively. These signals are further sent to a matrix circuit 92 via an R gamma correction circuit 89, a G gamma correction circuit 90, and a B gamma correction circuit 91, where the R, G, and B signals are converted to color difference signals (R −Y) and (B−Y) signals are generated. The (R−Y) signal and the (B−Y) signal are corrected by a color reproduction correction circuit 93, supplied to an encoder 94, processed together with a luminance signal output from a luminance signal gamma correction circuit 84, and processed as a composite video. Signal.

In a color television system, there are ideal spectral characteristics for obtaining ideal R, G, and B signals according to the system. If an image pickup device using a color filter based on the spectral characteristics is used, color reproduction is performed. No correction circuit is required.
However, since ideal spectral characteristics are difficult to realize,
The R, G, and B signals at the output of the color separation circuit 85 contain errors, and therefore, the (R−Y) signal and the
The (B−Y) signal also contains an error. The color reproduction correction circuit 93 performs correction so as to reduce this error.

The conventional color reproduction correction is expressed by the following equation [1]:
[2], which is described in JP-A-5-161152. (R−Y) ′ = (R−Y) + Gb · (B−Y) (1) (B−Y) ′ = (B−Y) + Gr · (R−Y) (2)

Here, (R−Y) ′ and (B−Y) ′ are the corrected (R−Y).
Y) and (B−Y). Gr and Gb are constants that determine the gain, and change in two steps, for example, as described below according to the magnitude of the (RY) signal or the (BY) signal. If (R−Y) ≧ Vrr, Gr = Gr1 (R−Y) <Vrr, Gr = Gr2 (B−Y) ≧ Vrb, Gb = Gb1 (B−Y) <Vrb, Gb = Gb2

Here, Vrr is a first reference value, and Vrb is a second reference value. In short, the value of Gr depends on the magnitude of the (R-Y) signal.
Switch to 1 and Gr2, and change the Gb value to Gb1 and Gb according to the magnitude of the (B−Y) signal.
Switch to b2.

FIG. 18 is a block diagram of an embodiment disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-161152. As shown in the figure, the first comparing section 101 compares the input (R−Y) signal with a first reference value Vrr. The second comparing unit 102 compares the input (B−Y) signal with the second reference value Vrb. The first gain switching unit 103 outputs an output of the first comparing unit 101
The first gain constant Gr1 or the second gain constant Gr2 is switched. The second gain switching unit 104 switches the third gain constant Gb1 or the fourth gain constant Gb2 according to the output of the second comparison unit 102. The first multiplication unit 105 multiplies any one of the gain constants selected by the first gain switching unit 103 and the (R−Y) signal. The second multiplication unit 106 multiplies any one of the gain constants selected by the second gain switching unit 104 and the (B−Y) signal. The first adder 107 is configured to output the (R−Y) signal and the second multiplier 106
And the output of. The second adder 108 adds the (B−Y) signal and the output of the first multiplier 105. In this configuration, the corrected signal (R−Y) ′ of the above equation [1] is output to the output of the first adder 107, and the corrected signal (B− Y) 'is output.

The operation of this circuit will be described below with reference to FIG. 16, which is a vector diagram when a color bar chart is imaged. Here, for convenience, the first reference value Vrr is described as 0, and the second reference value Vrb is also described as 0. In practice, each reference value uses an optimal value so that a good vector can be obtained.

First, it is assumed that Gr ≠ 0 and Gb = 0. Red is (R−Y)
> 0, (R−Y) ′ = (R−Y) (B−Y) ′ = (B−Y) + Gr1 · (R−Y) Since cyan has (R−Y) <0, (R−Y) ′ = (R−Y) (B−Y) ′ = (B−Y) + Gr2 · (R−Y)

Therefore, the phase of red can be adjusted by changing the value of Gr1, and the phase of cyan can be adjusted by changing the value of Gr2.
−Y) The phase can be changed in a direction parallel to the axis.
At this time, yellow and blue are not affected because the level of the (RY) signal is small.

Next, it is assumed that Gr = 0 and Gb ≠ 0. Yellow is (B−Y)
(R−Y) ′ = (R−Y) + Gb2 · (B−Y) (B−Y) ′ = (B−Y) Since blue has (B−Y)> 0, (R−Y) ′ = (R−Y) + Gb1 · (B−Y) (B−Y) ′ = (B−Y)

Therefore, the phase of yellow can be adjusted by changing the value of Gb2, and the phase of blue can be adjusted by changing the value of Gb1. Therefore, as shown in FIG. 19, the phase can be changed in the direction of the arrow, that is, in the direction parallel to the (RY) axis. At this time, red and cyan are not affected because the (B−Y) signal is small.

[0016]

However, the conventional digital signal processing camera described in Japanese Patent Application Laid-Open No. 6-141337 only extracts a specific color, and performs image quality correction such as color reproduction correction. When applying to colors other than colors, the same correction is applied except for specific colors, so that image quality correction such as accurate color reproduction correction cannot be performed.

The color reproduction correction circuit described in the above-mentioned conventional Japanese Patent Application Laid-Open No. 5-161152 increases the degree of freedom of color reproduction correction to perform red / cyan color reproduction correction and yellow / blue color reproduction correction. For example, as shown in FIG. 19, if correction is performed only for magenta only, the correction also affects red, so that magenta and red cannot be corrected separately. There was a problem that reproduction correction could not be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has an image signal processing apparatus capable of freely and more precisely adjusting the image quality of a color area to be adjusted, and having the image signal processing apparatus. It is intended to provide an imaging device.

[0019]

In order to solve the above-mentioned problems, the present invention provides a hue determining means for determining a hue from a video signal, a color reproduction correcting means for performing a color reproduction correction on the video signal, and a hue determining means. The video signal processing device is provided with color reproduction correction coefficient control means for changing the color reproduction correction coefficient of the color reproduction correction means according to the discrimination output of the means. With this configuration, it is possible to perform optimal color reproduction correction on a video signal in accordance with a hue, and reproduce each color more beautifully.

Further, hue discriminating means for discriminating the hue from the video signal, pedestal processing means for performing pedestal processing on the video signal, and pedestal value for making the pedestal value of the pedestal processing means variable according to the discrimination output of the hue discriminating means. The control means and the video signal processing device are provided. With such a configuration, optimal pedestal processing is performed on the video signal according to the hue to adjust the luminance, and each color can be reproduced more beautifully.

Further, hue discriminating means for discriminating the hue from the video signal, level compression / decompression processing means for performing level compression / decompression processing on the video signal, and level compression / decompression processing means in accordance with the discrimination output of the hue discrimination means And a level compression / expansion characteristic control means for changing the level compression / expansion characteristic of the video signal processing apparatus. With such a configuration, the optimal level compression / expansion processing is performed on the video signal according to the hue, and each color can be reproduced more beautifully.

Further, hue discriminating means for discriminating the hue from the video signal, contour emphasis processing means for performing contour correction processing on the video signal, and the detail amount of the contour emphasis processing means are changed according to the discrimination output of the hue discriminating means. The detail amount control means is provided in the video signal processing device. With such a configuration, it is possible to perform the optimum edge enhancement processing on the video signal according to the hue, and to reproduce each color more beautifully.

Further, the video signal processing device and the imaging means are provided in the imaging device. With this configuration, optimal color reproduction correction, pedestal processing, level compression / expansion processing, or contour enhancement processing is applied to the video signal according to the hue of the imaging signal obtained from the imaging means, and each color is reproduced more beautifully. can do.

Further, the image pickup apparatus is provided with means for recording the output of the video signal processing apparatus and means for transmitting the output. With this configuration, optimal color reproduction correction, pedestal processing, level compression / expansion processing, or contour enhancement processing is performed on the video signal in accordance with the hue of the imaging signal obtained from the imaging unit. Recording and transmission of the applied video signal can be performed.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a hue discriminating means for discriminating a hue from a video signal, a color reproduction correcting means for performing color reproduction correction on the video signal, and the hue discriminating means. A color reproduction correction coefficient control means for changing a color reproduction correction coefficient of the color reproduction correction means according to the discrimination output of the video signal processing apparatus, wherein the color reproduction correction according to the hue is performed on the video signal, This has the effect of performing a color reproduction correction with a variable color reproduction correction coefficient according to the hue determined from the video signal to the video signal.

According to a second aspect of the present invention, there is provided a hue discriminating means for discriminating a hue from a video signal, a pedestal processing means for performing pedestal processing on the video signal, and a discrimination output from the hue discriminating means. Pedestal processing means for variably changing the pedestal value of the pedestal processing means, the pedestal processing means for performing pedestal processing according to the hue to the video signal, the pedestal value according to the hue determined from the video signal Has an effect of performing a variable pedestal process on a video signal.

According to a third aspect of the present invention, there is provided a hue determining means for determining a hue from a video signal, a level compression / expansion processing means for performing a level compression / expansion processing on the video signal, and a hue determination means. Level compression / expansion characteristics control means for changing the level compression / expansion characteristics of the level compression / expansion processing means according to the discrimination output of the video signal, wherein the level compression / expansion processing corresponding to the hue is applied to the video signal. The signal processing device has an effect of performing level compression / expansion processing on a video signal in which level compression / expansion characteristics are variable according to a hue determined from a video signal.

According to a fourth aspect of the present invention, there is provided a hue discriminating means for discriminating a hue from a video signal, a contour emphasis processing means for performing contour correction processing on the video signal, and a discrimination output of the hue discriminating means. Detail amount control means for changing the detail amount of the contour emphasis processing means accordingly,
A video signal processing device that performs an outline correction process on the video signal according to the hue, and has an effect of performing an outline enhancement process on a video signal with a variable amount of detail according to a hue determined from the video signal.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the hue discriminating means is provided in units of areas divided by a plurality of mutually intersecting straight lines set on a color vector diagram. This is a video signal processing device that determines the hue, and has an effect of performing independent color reproduction correction on a video signal in units of areas divided by a plurality of straight lines that cross each other.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, the distance of the hue determined by the hue determining means from the plurality of straight lines is determined.
A video signal processing device for stopping color reproduction correction of the color reproduction correction means according to the result of the determination, performing independent color reproduction correction on the video signal in units of the regions, and performing the plurality of color hues of the determined hues. The color reproduction correction is stopped in accordance with the determination result of the distance from the straight line, and has an effect of preventing vector breakage.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the hue discriminating means includes a first comparator for comparing a first color difference signal input with a first reference value. Unit, a second comparison unit that compares a second color difference signal input with a second reference value, and an output of the first comparison unit and the second comparison unit.
And a first and a second switching means for switching and outputting a plurality of gain constants based on the output of the gain selection signal generating section. A gain switching unit; a first multiplication unit for multiplying the first color difference signal input by an output of the first gain switching unit; a second color difference signal input;
A second multiplication unit that multiplies the output of the gain switching unit, and a first addition unit that adds the first color difference signal input and the output of the second multiplication unit to obtain a first correction output And the second
And the output of the first multiplying unit is added to
A second adder for obtaining a second correction output, wherein the image signal processor identifies where the hue of the image exists in an area divided by the first and second color difference signal axes,
This has the effect of performing independent color reproduction correction on the video signal for each of the divided areas.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the hue discriminating means includes a first comparator for comparing a first color difference signal input with a first reference value. Unit, a second comparison unit that compares a second color difference signal input with a second reference value, and an output of the first comparison unit and the second comparison unit.
A gain selection signal generator for generating a signal for switching a plurality of gain constants based on the output of the comparison unit, and first and second switches for switching and outputting one of the plurality of gain constants based on an output of the gain selection signal generator. 2, a first multiplier for multiplying the first color difference signal input by the output of the first gain switch, and a second color difference signal input and the second gain switch. A second multiplication unit that multiplies the first and second color difference signal inputs with a third reference value, and a third comparison unit that multiplies the first and second color difference signal inputs with a third reference value. A first control unit that controls an output of the first multiplication unit by an output of the unit, a second control unit that controls an output of the second multiplication unit by an output of the third comparison unit, , The first color difference signal input and the output of the second control unit are added, and A video signal processing apparatus comprising: a first adder for obtaining an output; and a second adder for adding the second color difference signal input and the output of the first controller to obtain a second corrected output. Identifying where the hue of the image is located in the area divided by the first and second color difference signal axes, performing independent color reproduction correction on the image signal for each of the divided areas, and When the hue is at a distance equal to or less than the third reference value from the first and second color difference signal axes, the color reproduction correction is stopped.

According to a ninth aspect of the present invention, in the first aspect of the present invention, the hue discriminating means includes a first comparator for comparing a first color difference signal input with a first reference value. A second comparing section for comparing a second color difference signal input with a second reference value; a first color difference signal input with the second color difference signal input;
A third comparison unit for comparing the color difference signal input with the first, second, and third comparison units; and a gain selection signal generation unit for generating a signal for switching a plurality of gain constants based on the output of the first, second, and third comparison units.
A first gain switching unit that switches and outputs one of a plurality of gain constants according to an output of the gain selection signal generation unit; and a first gain switching unit that switches to one of a plurality of gain constants according to an output of the gain selection signal generation unit. 2, a gain switching unit;
A first multiplication unit that multiplies the first color difference signal input by the output of the first gain switching unit; and a second multiplication unit that multiplies the second color difference signal input by the output of the second gain switching unit. A multiplication unit, a first addition unit that adds the first color difference signal input and the output of the second multiplication unit to obtain a first correction output,
A video signal processing device comprising: a second addition unit that adds the second color difference signal input and the output of the first multiplication unit to obtain a second corrected output; It has the effect of identifying where in the area divided by the second color difference signal axis and the first and second straight lines exists and applying independent color reproduction correction to the video signal for each of the divided areas.

According to a tenth aspect of the present invention, in the first aspect of the invention, the hue discriminating means comprises:
A first comparing unit that compares the first color difference signal input with the first reference value, a second comparing unit that compares the second color difference signal input with the second reference value, and a first color difference A third comparison unit for comparing the signal input with the second color difference signal input, and a gain selection signal generation for generating a signal for switching a plurality of gain constants by an output of the first, second, and third comparison units. Unit, a first and second gain switching unit for switching and outputting any one of a plurality of gain constants according to the output of the gain selection signal generation unit, the first color difference signal input and the first gain switching A first multiplier for multiplying the output of the second unit, a second multiplier for multiplying the second color difference signal input by the output of the second gain switching unit, and the first color difference signal input. A fourth comparing unit that compares a difference between the second color difference signal input and a third reference value, and a fourth ratio A first control unit that controls an output of the first multiplication unit by an output of the unit, a second control unit that controls an output of the second multiplication unit by an output of the fourth comparison unit, A first adder for adding a first color difference signal input and an output of the second controller to obtain a first corrected output; a second color difference signal input and an output of the first controller; And a second adder for obtaining a second corrected output, wherein the hue of the image is divided by the first and second color difference signal axes and the first and second straight lines. The image signal is subjected to independent color reproduction correction for each of the divided areas, and the hue of the image is changed to the first and second color difference signal axes or the first and second color difference signal axes. When the distance from the straight line is equal to or less than the third reference value, the color reproduction correction is stopped.

According to an eleventh aspect of the present invention, there is provided an image pickup apparatus comprising the video signal processing device according to any one of the first to tenth aspects and an image pickup means. It has an effect of performing optimal color reproduction correction, pedestal processing, level compression / expansion processing, or contour emphasis processing on the obtained image signal in accordance with the hue.

According to a twelfth aspect of the present invention, in accordance with the eleventh aspect of the present invention, there is provided an imaging apparatus provided with means for recording an output of the video signal processing apparatus. In this case, an optimum color reproduction correction, a pedestal process, a level compression / expansion process, or an outline emphasis process according to the hue is performed and recorded.

According to a thirteenth aspect of the present invention, in accordance with the eleventh aspect of the present invention, there is provided an imaging apparatus provided with a means for transmitting an output of the video signal processing apparatus. In this way, it has the effect of performing optimal color reproduction correction, pedestal processing, level compression / expansion processing, or contour enhancement processing according to the hue, and transmitting the result.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an imaging device according to an embodiment of the present invention.

In this image pickup apparatus, the image pickup device 1 has a CC
A D image sensor or the like, which captures an image of a subject and generates an imaging signal. The low-pass filter 2 separates a luminance signal from an output signal of the image sensor 1. The luminance signal processing unit 3 performs correction such as gain adjustment, gamma correction, contour enhancement correction, and pedestal correction on the luminance signal separated by the low-pass filter 2. The color signal processing unit 4 separates the R, G, and B signals from the output of the image sensor 1,
Performs corrections such as gamma correction, gain correction, and color reproduction correction. The hue discriminating unit 5 discriminates the hue of the image from the color signals {for example, the (R−Y) signal and the (B−Y) signal} generated by the color signal processing unit 4. The coefficient generator 7 generates coefficients for setting various processing characteristics of the color signal processor 4 and the luminance signal processor 3. The coefficient control unit 6 switches various coefficients given from the coefficient generation unit 7 based on the hue determination information of the hue determination unit 5 and supplies the luminance signal processing unit 3 and the color signal processing unit 4 with coefficients corresponding to the hue of the subject.

The output control unit 8 performs processing for recording the luminance signal output from the luminance signal processing unit 3 and the color signal output from the color signal processing unit 4 on the recording medium 10 and the transmission unit 11.
For transmitting to the outside via the. The control unit 9 controls the output timing of the output control unit 8 and various parameters in the output processing. The control unit 9 is configured using, for example, a microcomputer and, if necessary, a peripheral circuit such as a RAM or a ROM. Note that a part or all of the signal processing performed by the output control unit 8 may be performed by the control unit 9. In the control unit 9, J
Image compression such as PEG may be performed by software processing.

As the recording medium 10, a semiconductor memory such as a flash memory is preferably used.
A rewritable magnetic disk, magnetic tape, optical disk, or the like may be used. Furthermore, like a memory card,
A recording medium from which data in the memory can be read by an external device such as a personal computer may be used. Transmission section
Numeral 11 can transmit an image to an external personal computer or the like by Ethernet or IEEE1394. Input / output of video signal data between the output control unit 8, the control unit 9, and the recording medium 10 is performed via the bus 12.

As described above, in the image pickup apparatus according to the present embodiment, color reproduction correction in the color signal processing unit 4, pedestal processing in the luminance signal processing unit 3, Since gamma correction processing, knee correction processing, contour enhancement processing, and the like can be performed, each color can be reproduced more beautifully. Further, it has a function of generating a luminance signal and a chrominance signal from an imaging signal output from the imaging device 1 and recording the luminance signal and the chrominance signal on the recording medium 10 and inputting them to a personal computer or the like via the transmission unit 11. , Easy to use.

Next, the color reproduction correction of the color signal processing section 4, hue discriminating section 5, coefficient control section 6, and coefficient generating section 7 of FIG. 1 will be described. Here, the first to fourth color reproduction corrections will be described in order.

(First Color Reproduction Correction Circuit) In the first color reproduction correction circuit, four signals are obtained depending on the magnitudes of the (R−Y) signal and the (B−Y) signal.
The hue condition, that is, the (R−Y) axis, which is two straight lines where the hue of the image intersects each other set on the color vector diagram, and the (B
-Y) It identifies which one of the first to fourth quadrants belongs to the axis, and switches the color reproduction correction coefficient according to the four hue conditions.

The first color reproduction correction circuit is given by the following equation [3].
The correction represented by [4] is performed. (RY) '= (RY) + Gb' (BY) ... [3] (BY) '= (BY) + Gr' (RY) ... [4]

Here, Gr 'and Gb' are constants for determining the gain, and change as follows according to the magnitudes of the (RY) signal and the (BY) signal. If (R−Y) ≧ Vrr and (B−Y) ≧ Vrb, Gr ′ = Gr1 and Gb ′ = G
b1 If (R−Y) ≧ Vrr and (B−Y) <Vrb, Gr ′ = Gr2 and Gb ′ = G
b2 If (R−Y) <Vrr and (B−Y) <Vrb, Gr ′ = Gr3 and Gb ′ = G
b3 If (R−Y) <Vrr and (B−Y) ≧ Vrb, Gr ′ = Gr4 and Gb ′ = G
b4

Here, Vrr is a first reference value, and Vrb is a second reference value. In short, four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the values of Gr ′ and Gb ′ are switched according to the four hue conditions.

FIG. 2 is a block diagram showing the configuration of the first color reproduction correction circuit. In this color reproduction correction circuit, the first comparing section 21 converts the (R−Y) signal, which is the first color difference signal, into the first signal.
The second comparison unit 22 compares the (B−Y) signal, which is the second color difference signal, with the second reference value Vrb. These comparison units 21 and 22 correspond to the hue determination unit 5 in FIG.
The first gain switching unit 24 includes first to fourth gain coefficients Gr1 to Gr4.
Is input, and one of them is selected and output. Similarly,
The second gain switching section 25 includes fifth to eighth gain coefficients Gb1 to Gb4.
Is input, and one of them is selected and output. The gain selection signal generation unit 23 generates four types of gain selection signals based on the above conditions based on the output of the first comparison unit 21 and the output of the second comparison unit 22, and outputs the first and second gain switching units 24. , Feed to 25. The first and second gain switching units 24 and 25 and the gain selection signal generation unit 23 correspond to the coefficient control unit 6 in FIG. The first multiplier 26 multiplies any one of the gain constants selected by the first gain switch 24 by the (R−Y) signal. The second multiplication unit 27 multiplies any one of the gain constants selected by the second gain switching unit 25 and the (B−Y) signal. First adder 28
Adds (R−Y) to the output of the second multiplier 27. Second
Adder 29 adds (B−Y) to the output of the first multiplier 26. These multiplication units 26 and 27 and addition units 28 and 29 correspond to the color signal processing unit 4 in FIG. The first adder 28 outputs a (R−Y) ′ signal which is a first color difference signal subjected to color reproduction correction,
The second adder 29 outputs a (B−Y) ′ signal which is a second color difference signal subjected to color reproduction correction.

Next, the operation of the color reproduction correction circuit will be described below with reference to FIG. 3 which is a color vector diagram when a color bar chart is picked up. Here, for convenience, the first
It is assumed that the reference value Vrr is 0 and the second reference value Vrb is also 0. In practice, each reference value uses an optimal value so that a good vector can be obtained.

First, for example, assuming that Gr ≠ 0 and Gb = 0, FIG.
The description will be made by taking red and magenta existing in the first and second quadrants {(R−Y) ≧ 0} as an example.

Since (R−Y)> 0 and (B−Y) <0 for red, (R−Y) ′ = (R−Y) (5) (B−Y) ′ = (B− Y) + Gr2 · (R−Y)... [6], and since magenta is (R−Y)> 0 and (B−Y)> 0, (R−Y) ′ = (R−Y). 7] (B−Y) ′ = (B−Y) + Gr1 · (R−Y) (8)

Therefore, the red phase can be adjusted by changing the value of Gr2, and the magenta phase can be adjusted by changing the value of Gr1. At this time, the red phase and the magenta phase are corrected in a direction parallel to the (B-Y) axis in FIG.

In the above case, Gb = 0, but
In actual correction, the value is not always 0 because of fine adjustment. For example, when Gr = 0 and Gb ≠ 0, red is (R−Y) ′ = (R−Y) + Gb2 · (B−Y)... [9] (B−Y) ′ = (B−Y). 10], and magenta is (R−Y) ′ = (R−Y) + Gb1 · (B−Y) (11) (B−Y) ′ = (B−Y) (12) Therefore, in this case, the phase of red can be adjusted by changing Gb2, and the phase of magenta can be adjusted by changing Gb1. At this time, the red phase and the magenta phase are corrected in a direction parallel to the (RY) axis in FIG.

Therefore, by changing Gr2 and Gb2, the red phase can be two-dimensionally corrected on the vector diagram. Also, by changing Gr1 and Gb1, the red phase can be corrected two-dimensionally.

The red and magenta have been described above.
As shown in FIG. 3, the yellow phase is changed by changing Gr2 and Gb2, the green phase is changed by changing Gr3 and Gb3, and the blue and cyan phases are changed by changing Gr4 and Gb4. It can be corrected two-dimensionally.
In the conventional color reproduction correction method, when Gb ≠ 0, even when the (B−Y) component of magenta is small, blue is affected when magenta is adjusted, but the first color In the reproduction correction circuit, correction can be made independently for four quadrants.
It does not affect blue when adjusting magenta.

As described above, in the first color reproduction correction circuit,
The (R−Y) axis and the (R−Y) axis, which are two straight lines that intersect each other on the four hue condition, that is, the hue of the image set on the color vector diagram, according to the magnitudes of the (R−Y) signal and the (B−Y) signal, By identifying which of the first to fourth quadrants divided by the (B-Y) axis belongs and switching the values of Gr 'and Gb' according to the four hue conditions, the first to fourth quadrants of the first to fourth quadrants are switched. Independent color reproduction correction can be performed on the hue.

(Second Color Reproduction Correction Circuit) The second color reproduction correction circuit supplies the (R−Y) signal input and the (B−Y) signal input to the first color reproduction correction circuit described above. A third comparing unit that compares the output with the third reference value Th, a first control unit that controls the output of the first multiplying unit with the output of the third comparing unit, and a third control unit that outputs with the output of the third comparing unit. And a second control unit for controlling the output of the multiplication unit of 2.

The second color reproduction correction circuit is basically the same correction as the first color reproduction correction circuit, that is, the equation [3],
The correction shown in [4] is performed. However, the second color reproduction correction circuit is used when the hue to be corrected exists at a distance less than a predetermined reference value from the (RY) axis or the (BY) axis shown in FIG. Stop the correction.

FIG. 4 is a block diagram showing the configuration of the second color reproduction correction circuit. In this block diagram, the first,
The second comparison units 31 and 32, the gain selection signal generation unit 33, the first
Second gain switching units 34 and 35, first and second multiplication units 36 and 3
7, the first and second adders 38 and 39 are the first and second comparators 21 and 22, the gain selection signal generator 23, and the first and second gain switches 24 and 25 in FIG. , First and second multiplication units 2
6, 27 and the second adders 28 and 29 have the same configuration.
The third comparing unit 40 compares the (R−Y) signal as the first color difference signal and the (B−Y) signal as the second color difference signal with a third reference value Th, and compares the comparison result. Accordingly, the first control unit 41
Of the multiplication unit 36, and the second control unit 42
Controls the output of the second multiplier 37. The control contents are as follows. If (R−Y) <Th… [13] or − (R−Y) <Th… [14] or (B−Y) <Th… [15] or − (B−Y) <Th… [16] For example, the output of the first multiplier 36 and the output of the second multiplier 37 are set to 0.

Therefore, if at least one of these conditions is satisfied, the value added to the (R−Y) signal in the first adder 38 is 0, and the value (B−B) is added in the second adder 39. The value added to the Y) signal is 0. That is, no correction is performed, the (RY) signal becomes the (RY) 'signal as it is, and the (BY) signal is
−Y) ′ signal. On the other hand, if none of these conditions is satisfied, the same correction as in the first color reproduction correction circuit is performed.

Next, the operation of the second color reproduction correction circuit will be described below with reference to FIGS. 3, 5 to 7 which are vector diagrams when a color bar chart is picked up. First, the correction operation when none of the above conditions [13] to [16] is satisfied is the same as that of the first color reproduction correction circuit. That is,
Since the correction is performed according to the expressions [3] to [12], the correction is performed as shown in FIG. On the contrary,
When at least one of the conditions [13] to [16] is satisfied, for example, as shown in FIG. 5, the hue to be corrected is (R
-Y) If the object exists in the area P0 on or near the axis, the correction is stopped because the condition [15] or [16] is satisfied.

The reason why the correction is stopped in the case as shown in FIG. 5 is as follows. When the correction is performed in accordance with the equations [3] to [12], as shown in FIG. 6A, the hues existing in the region P0 are theoretically rightward from the (RY) axis, that is, (B For the hue of (−Y) ≧ 0, the phase is adjusted by Gr1 and Gb1, and the left side of the (R−Y) axis, that is, (B−
Y) For the hue of <0, the phase is adjusted by Gr2 and Gb2. However, in actual correction, there is a possibility that vector breakage may occur as shown in FIG. Therefore, in the second color reproduction correction circuit, if at least one of [13] to [16] is satisfied as shown in FIG. 7A, in other words, the hue to be corrected is (R−Y The color reproduction correction is stopped when the color reproduction correction is present at a distance less than the predetermined reference value Th from the ()) axis or the (B-Y) axis, or in other words, when it exists in the boundary area of the gain switching of the color reproduction correction. . As a result, as shown in FIG. 7B, vector breakage can be prevented, and more accurate color reproduction correction can be performed. The reference value of the (RY) signal input and the reference value of the (BY) signal input may be different values.

As described above, in the second color reproduction correction circuit,
When the constants Gr ′ and Gb ′ that determine the gain by identifying the four hue conditions according to the magnitude of the (R−Y) signal and (B−Y) are switched and the identified hue exists in the boundary region of the four hue conditions Since the color reproduction correction is stopped, independent color reproduction correction can be performed for the hues of the first to fourth quadrants, and vector breakage can be prevented.

(Third Color Reproduction Correction Circuit) The third color reproduction correction circuit compares the (R−Y) signal input and the (B−Y) signal input to the above-described first color reproduction correction circuit. A third comparison unit is provided to change the condition in the gain selection signal generation unit.
The number of coefficients of the second gain switching unit is increased.

The third color reproduction correction circuit uses the following equations [17] to [17].
The correction represented by [18] is performed. (R−Y) ′ = (R−Y) + Gb ′ · (B−Y)… [17] (B−Y) ′ = (B−Y) + Gr ′ · (R−Y)… [18]

Here, Gr 'and Gb' are constants for determining the gain, and change as follows according to the magnitudes of the (RY) signal and the (BY) signal. G if (R−Y) ≧ Vrr and (B−Y) ≧ Vrb and (R−Y) <(B−Y)
r '= Gr1 and Gb' = Gb1 If (R−Y) ≧ Vrr and (B−Y) ≧ Vrb and (R−Y) ≧ (B−Y), G
r '= Gr2 and Gb' = Gb2 If (R−Y) ≧ Vrr and (B−Y) <Vrb and (R−Y) ≧ − (B−Y)
Gr '= Gr3 and Gb' = Gb3 If (R−Y) ≧ Vrr and (B−Y) <Vrb and (R−Y) <− (B−Y)
If Gr ′ = Gr4 and Gb ′ = Gb4 (R−Y) <Vrr and (B−Y) <Vrb and − (R−Y) <− (B−Y), then r ′ = Gr5 and Gb ′ = Gb5 ( If (R−Y) <Vrr and (B−Y) <Vrb and − (R−Y) ≧ − (B−Y), Gr ′ = Gr6 and Gb ′ = Gb6 (R−Y) <Vrr and (B− Y) ≧ Vrb and − (R−Y) <(B−Y)
Gr '= Gr7 and Gb' = Gb7 (R−Y) <Vrr and (B−Y) ≧ Vrb and − (R−Y) ≧ (B−Y)
Gr '= Gr8 and Gb' = Gb8

Here, Vrr is a first reference value, and Vrb is a second reference value. In short, eight hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the values of Gr ′ and Gb ′ are switched according to the eight hue conditions.

FIG. 8 is a block diagram showing the configuration of the third color reproduction correction circuit. In this block diagram, the first,
The second comparing sections 51 and 52, the first and second multiplying sections 56 and 57, and the first and second adding sections 58 and 59 respectively correspond to the first and second adding sections shown in FIG.
, And the first and second multiplication units 26 and 27, and the first and second addition units 28 and 29. The third comparing section 60 compares the magnitudes of the (RY) signal and the (BY) signal. The gain selection signal generation unit 53 is configured to output the output of the first comparison unit 51 and the second
Based on the output of the comparison unit 52 and the output of the third comparison unit 60, eight kinds of gain selection signals are generated under the above conditions. First
The gain switching unit 54 switches the first to eighth gain constants Gr1 to Gr8 according to the output signal of the gain selection signal generation unit 53.
The second gain switching unit 55 switches the ninth to sixteenth gain constants Gb1 to Gb8 according to the output signal of the gain selection signal generation unit 53.

Next, the operation of the third color reproduction correction circuit will be described with reference to the vector diagram of FIG.
This will be described below with reference to FIG. Here, for convenience, the first reference value Vrr is described as 0, and the second reference value Vrb is also described as 0.
In practice, each reference value uses an optimal value so that a good vector can be obtained.

For example, in the second quadrant ｛(R−Y) ≧ 0 of FIG.
The red and yellow existing at (B−Y) <0 ° will be described.

Red is (R−Y)> 0, (B−Y) <0, (R−Y)> −
Since (B−Y), (R−Y) ′ = (R−Y) + Gb3 · (B−Y) (B−Y) ′ = (B−Y) + Gr3 · (R−Y) Since (R−Y)> 0, (B−Y) <0, and (R−Y) <− (B−Y), (R−Y) ′ = (R−Y) + Gb4 · (B−Y) ( (B−Y) ′ = (B−Y) + Gr4 · (R−Y)

Therefore, the red phase can be adjusted by changing Gr3 and Gb3, and the yellow phase can be adjusted by changing Gr4 and Gb4. Similarly, Gr
2.Change the phase of magenta by changing Gb2, Gr
6, green phase by changing Gb6, Gr7, Gb7
, The blue phase can be independently changed by changing Gr8 and Gb8.

As described above, in the third color reproduction correction circuit,
Eight hue conditions, that is, the hue of an image is represented by (R-Y) in the color vector diagram according to the magnitude of the (R−Y) signal and (B−Y).
Axes A, (B−Y) and an orthogonal line A passing through the origin
-It is determined which of the eight regions divided by A 'and BB' belongs, and the values of Gr 'and Gb' are switched according to the eight hue conditions. Color reproduction correction.

(Fourth Color Reproduction Correction Circuit) The fourth color reproduction correction circuit uses the (R−Y) signal and the (B−Y) signal as a third reference with respect to the third color reproduction correction circuit. A fourth comparison unit for comparing the output with the value, a first control unit for controlling the output of the first multiplication unit based on the output of the fourth comparison unit, and a second control unit based on the output of the fourth comparison unit.
And a second control unit for controlling the output of the multiplication unit. That is, it can be said that the third color reproduction correction circuit and the second color reproduction correction circuit are combined.

The fourth color reproduction correction circuit is basically the same correction as the third color reproduction correction circuit, that is, the equations [17] and [1]
8]. However, in the fourth color reproduction correction circuit, the hue to be corrected has the (R-Y) axis shown in FIG.
If the distance from any one of the (BY) axis, the straight line AA 'or the straight line BB' is less than a predetermined reference value, the correction is stopped.

FIG. 10 is a block diagram showing the configuration of the fourth color reproduction correction circuit. In this block diagram, first, second, and third comparison units 61, 62, and 73, a gain selection signal generation unit 63, first and second gain switching units 64 and 65, first and second
, The first, second and third comparing units 5 of the color reproduction correction circuit of FIG.
1, 52, 60, a gain selection signal generation unit 53, first and second gain switching units 54, 55, first and second multiplication units 56, 57, first,
The configuration is the same as that of the second adders 58 and 59. The fourth comparing unit 70 compares the (R−Y) signal as the first color difference signal and the (B−Y) signal as the second color difference signal with a third reference value Th, and compares the comparison result. Accordingly, the first control unit 71 controls the first multiplication unit.
The output of 66 is controlled, and the output of the second multiplier 67 is controlled by the second controller 72. The control contents are as follows. (R−Y) <Th… [19] or − (R−Y) <Th… [20] or (B−Y) <Th… [21] or − (B−Y) <Th… [22] or If | (R−Y) | − | (B−Y) | <Th (23), the output of the first multiplier 66 and the output of the second multiplier 67 are set to 0.

Therefore, if at least one of these conditions is satisfied, the value added to the (R−Y) signal in the first adder 68 is 0, and the value (B−B) is added in the second adder 69. The value added to the Y) signal is 0. That is, no correction is performed, the (RY) signal becomes the (RY) 'signal as it is, and the (BY) signal is
−Y) ′ signal. On the other hand, if none of these conditions is satisfied, the same correction is performed as in the third color reproduction correction circuit.

Next, the operation of the fourth color reproduction correction circuit will be described below with reference to FIGS. 9 and 11 to 13 which are vector diagrams when a color bar chart is picked up. First, the correction operation when none of the conditions [19] to [23] described above is satisfied is the same as that of the third color reproduction correction circuit. That is,
The correction is performed as shown in FIG. On the contrary,
When at least one of the conditions [19] to [23] is satisfied, for example, as shown in FIG. 11, the hue to be corrected exists on the straight line AA ′ or in the area P1 in the vicinity thereof. If so, the correction is stopped because the condition of [23] is satisfied.

The reason for stopping the correction in the case as shown in FIG. 11 is as follows. When performing the same correction as the third color reproduction correction circuit, as shown in FIG. 12A, the clock is theoretically calculated from the straight line AA ′ among the hues existing in the area P1. The rotation side, that is, (R−Y) <(B
-Y), the phase is adjusted by Gr1 and Gb1, and the hue is set on the counterclockwise side from the line AA ′, that is, (R−Y) ≧
With respect to the hue (B−Y), phase adjustment is performed using Gr2 and Gb2. However, in the actual correction, there is a possibility that a vector break may occur as shown in FIG. Therefore, in the fourth color reproduction correction circuit, when at least one of [19] to [23] is satisfied as shown in FIG. 13A, in other words, the hue to be corrected is (R−Y ) Axis or (BY) axis or any one of the straight line AA 'or the straight line BB' at a predetermined distance less than the reference value Th, in other words, the hue determination of the color reproduction correction If it exists in the boundary area, the color reproduction correction is stopped. As a result, as shown in FIG. 13B, it is possible to prevent vector breakage and to perform more accurate color reproduction correction.

As described above, in the fourth color reproduction correction circuit,
When the constants Gr ′ and Gb ′ that determine the gain by identifying the eight hue conditions according to the magnitude of the (R−Y) signal and (B−Y) are switched, and the identified hue exists in the boundary region of the eight hue conditions , The color reproduction correction is stopped, so that the color vector diagram is divided by the (R−Y) axis, the (B−Y) axis, and the mutually orthogonal straight lines AA ′ and BB ′ passing through the origin. Independent color reproduction correction can be performed on one area and vector breakage can be prevented.

(Pedestal Processing Circuit) In the pedestal processing circuit according to the embodiment of the present invention, four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the pedestal processing circuit is responsive to the four hue conditions. The petestal value is being switched. This pedestal processing circuit performs pedestal processing represented by the following equation [24]. Y '= Y + Pd [24]

Here, Pd is a pedestal value, and changes as follows according to the magnitudes of the (RY) signal and the (BY) signal. If (R−Y) ≧ Vrr and (B−Y) ≧ Vrb, then Pd = Pd1 (R−Y) ≧ Vrr and (B−Y) <Vrb if Pd = Pd2 (R−Y) <Vrr and (B−Y) ) <Vrb, Pd = Pd3 (R−Y) <Vrr and (B−Y) ≧ Vrb, Pd = Pd4

Here, Vrr is a first reference value, and Vrb is a second reference value. Note that, for convenience, the signs of the first reference value and the second reference value are the same as the signs used in the color reproduction correction circuit, but they do not necessarily mean the same value (the same applies to the following embodiments). ).

FIG. 14 is a block diagram showing the configuration of the pedestal processing circuit. In this pedestal processing circuit, the first comparing section 201 compares the (R−Y) signal as the first color difference signal with a first reference value Vrr, and the second comparing section 202
Is compared with the second reference value Vrb. These comparison units 201 and 202 correspond to the hue determination unit 5 in FIG. The pedestal value switching unit 204 receives the first to fourth pedestal values Pd1 to Pd4, selects one of them, and outputs it. The pedestal value selection signal generation unit 203 generates four types of pedestal value selection signals based on the above-described conditions based on the output of the first comparison unit 201 and the output of the second comparison unit 202, and supplies them to the pedestal value switching unit 204. . Pedestal value switching unit 204
The pedestal value selection signal generation unit 203 corresponds to the coefficient control unit 6 in FIG. The adding unit 205 adds one of the pedestal values selected by the pedestal value switching unit 204 to the Y signal and outputs the signal as a Y ′ signal.

As described above, in the pedestal processing circuit according to the embodiment of the present invention, the four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the petestal value is determined according to the four hue conditions. , The pedestal value appropriate for the hues of the first to fourth quadrants can be set independently for each quadrant.

(Level Compression / Expansion Processing Circuit) In the level compression / expansion processing circuit according to the embodiment of the present invention, four hue conditions are identified based on the magnitudes of the (R-Y) signal and the (B-Y) signal. The gain of the Y signal is switched according to the four hue conditions. This level compression / expansion processing circuit performs level compression / expansion processing represented by the following equation [25]. Y '= Y × Gy ... [25]

Here, Gy is a coefficient for setting the gain, and (R
It changes as follows according to the magnitude of the (−Y) signal and the (B−Y) signal. If (R−Y) ≧ Vrr and (B−Y) ≧ Vrb, Gy = Gy1 (R−Y) ≧ Vrr and (B−Y) <Vrb, Gy = Gy2 (R−Y) <Vrr and (B−Y) ) <Vrb, Gy = Gy3 (R−Y) <Vrr and (B−Y) ≧ Vrb, Gy = Gy4 where Vrr is a first reference value and Vrb is a second reference value.

FIG. 15 is a block diagram showing the configuration of the level compression / expansion processing circuit. In this level compression / expansion processing circuit, the first comparing section 211 compares the (R−Y) signal, which is the first color difference signal, with the first reference value Vrr, and the second comparing section 212 outputs the second reference value Vrr. The (B−Y) signal, which is a color difference signal, is compared with a second reference value Vrb. These comparison units 211 and 212 correspond to the hue determination unit 5 in FIG. The gain switching unit 214 includes first to fourth
Are input, and one of them is selected and output. The gain selection signal generation unit 213 generates a signal for selecting four types of coefficient values based on the above conditions based on the output of the first comparison unit 211 and the output of the second comparison unit 212,
Supply to 214. The gain switching unit 214 and the gain selection signal generation unit 213 correspond to the coefficient control unit 6 in FIG. The multiplication unit 215 sets any of the gains selected by the gain switching unit 201 to Y
The signal is multiplied and output as a Y 'signal.

As described above, in the level compression / expansion processing circuit according to the embodiment of the present invention, the four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and according to the four hue conditions. Since the gain of the Y signal is switched in this manner, appropriate level compression / decompression processing can be performed independently for each of the hues in the first to fourth quadrants.

(Contour Correction Circuit) In the contour correction circuit according to the embodiment of the present invention, four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the four hue conditions are determined. The detail amount of contour emphasis is switched. This contour correction circuit performs a contour emphasis process represented by the following equation [26]. Y '= Y + Y × Co ... [26]

Here, Go is a coefficient for switching the detail amount of the edge enhancement, and changes as follows depending on the magnitudes of the (R−Y) signal and the (B−Y) signal. If (R−Y) ≧ Vrr and (B−Y) ≧ Vrb, then Co = Co1 (R−Y) ≧ Vrr and (B−Y) <Vrb if Co = Co2 (R−Y) <Vrr and (B−Y) ) <Vrb, Co = Co3 (R−Y) <Vrr and (B−Y) ≧ Vrb, Co = Co4 where Vrr is a first reference value and Vrb is a second reference value.

FIG. 16 is a block diagram showing the configuration of the contour correction circuit. In this contour correction circuit, the first comparing section 221 compares the (R−Y) signal, which is the first color difference signal, with the first reference value Vrr, and the second comparing section 222 uses the second color difference signal. A certain (B−Y) signal is compared with a second reference value Vrb. These comparison units 221 and 222 correspond to the hue determination unit 5 in FIG. The detail amount switching unit 224 receives the first to fourth coefficients Co1 to Co4, selects one of them, and outputs it. The detail amount selection signal generation unit 223 generates a signal for selecting four types of coefficient values based on the above conditions based on the output of the first comparison unit 221 and the output of the second comparison unit 222, and sends the signal to the detail amount switching unit 224. Supply. The detail amount switching unit 224 and the detail amount selection signal generation unit 223 correspond to the coefficient control unit 6 in FIG. The contour correction unit 226 generates a contour correction signal in which the detail amount of the Y signal is controlled according to the coefficient value selected by the detail amount switching unit 224, and outputs the signal to the adding unit 225. The adder 225 adds the contour correction signal to the Y signal and outputs the result as a Y ′ signal.

As described above, in the contour correction circuit according to the embodiment of the present invention, the four hue conditions are identified based on the magnitudes of the (R−Y) signal and the (B−Y) signal, and the contour correction is performed according to the four hue conditions. Since the detail amount of the signal is switched, it is possible to perform an appropriate contour correction process for the hues of the first to fourth quadrants independently for each quadrant.

[0094]

As described above, according to the present invention, the hue discriminating means for discriminating the hue from the video signal, the color reproduction correcting means for performing color reproduction correction on the video signal, and the color reproduction in accordance with the discrimination output of the hue discriminating means. Since the video signal processing circuit is provided with the color reproduction correction coefficient control means for changing the color reproduction correction coefficient of the correction means, the optimum color reproduction correction is applied to the video signal according to the hue to reproduce each color more beautifully. The effect that it can be obtained is obtained.

Further, hue discriminating means for discriminating the hue from the video signal, pedestal processing means for performing pedestal processing on the video signal, and pedestal value for making the pedestal value of the pedestal processing means variable according to the discrimination output of the hue discriminating means. Since the control means and the video signal processing device are configured to be provided,
The effect is obtained that the optimum pedestal processing is performed on the video signal according to the hue to adjust the luminance and each color can be reproduced more beautifully.

Further, hue discriminating means for discriminating the hue from the video signal, level compression / decompression processing means for performing level compression / decompression processing on the video signal, and level compression / decompression processing means in accordance with the discrimination output of the hue discrimination means And the level compression / expansion characteristics control means for changing the level compression / expansion characteristics of the video signal are provided in the video signal processing device, so that the optimal level compression / expansion processing is applied to the video signal according to the hue to adjust the brightness. Thus, the effect that each color can be reproduced more beautifully can be obtained.

Further, hue discriminating means for discriminating the hue from the video signal, contour emphasis processing means for performing contour correction processing on the video signal, and changing the detail amount of the contour emphasis processing means in accordance with the discrimination output of the hue discriminating means. Since the detail signal control means and the video signal processing device are provided in the video signal processing device, the effect is obtained that the optimum edge enhancement processing is applied to the video signal according to the hue to adjust the luminance, and each color can be reproduced more beautifully. Can be

Further, since the video signal processing device and the image pickup device are provided in the image pickup device, the optimum color reproduction correction and the color reproduction correction can be performed according to the hue of the image pickup signal obtained from the image pickup device.
Pedestal processing, level compression / expansion processing, or contour emphasis processing is performed on the video signal, so that the effect that each color can be reproduced more beautifully can be obtained.

Since this image pickup apparatus is provided with a means for recording the output of the video signal processing apparatus and a means for transmitting the same, optimal color reproduction correction and pedestal control are performed in accordance with the hue of the image signal obtained from the image pickup means. Processing, level compression
The effect is obtained that the decompression process or the outline emphasis process is performed on the video signal, and the video signal subjected to these processes can be recorded or transmitted.

[Brief description of the drawings]

FIG. 1 is a block diagram of an imaging apparatus according to an embodiment of the present invention;

FIG. 2 is a block diagram of a first color reproduction correction circuit according to the embodiment of the present invention;

FIG. 3 is a color vector diagram of a first color reproduction correction circuit and a second color reproduction correction circuit according to the embodiment of the present invention;

FIG. 4 is a block diagram of a second color reproduction correction circuit according to the embodiment of the present invention;

FIG. 5 is a color vector diagram when a hue exists in a boundary region of gain switching in the second color reproduction correction circuit;

6A is an explanatory diagram showing phase adjustment in a boundary region of gain switching in the first color reproduction correction circuit, and FIG. 6B is an explanatory diagram showing vector breaks in the first color reproduction correction circuit.

7A is an explanatory diagram showing a phase adjustment in a boundary region of gain switching in the second color reproduction correction circuit, and FIG. 7B is an explanatory diagram of vector break prevention in the second color reproduction correction circuit.

FIG. 8 is a block diagram of a third color reproduction correction circuit according to the embodiment of the present invention;

FIG. 9 is a color vector diagram of a third color reproduction correction circuit and a fourth color reproduction correction circuit according to the embodiment of the present invention;

FIG. 10 is a block diagram of a fourth color reproduction correction circuit according to the embodiment of the present invention;

FIG. 11 is a color vector diagram when a hue exists in a boundary region of gain switching in the fourth color reproduction correction circuit;

12A is an explanatory diagram showing phase adjustment in a boundary region of gain switching in the third color reproduction correction circuit, and FIG.
Explanatory diagram showing a vector break in the third color reproduction correction circuit,

13A is an explanatory diagram showing phase adjustment in a boundary region of gain switching in the fourth color reproduction correction circuit, and FIG.
Explanatory drawing of prevention of vector breakage in the fourth color reproduction correction circuit,

FIG. 14 is a block diagram showing a configuration of a pedestal processing circuit according to an embodiment of the present invention;

FIG. 15 is a block diagram showing a configuration of a level compression / expansion processing circuit according to the embodiment of the present invention;

FIG. 16 is a block diagram illustrating a configuration of a contour correction circuit according to an embodiment of the present invention.

FIG. 17 is a block diagram of an imaging device for explaining a conventional example;

FIG. 18 is a block diagram of a color reproduction correction circuit in a conventional example,

FIG. 19 is a color vector diagram when a color bar chart is imaged in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image sensor 3 Luminance signal processing part 4 Color signal processing part 5 Hue discrimination part 6 Coefficient control part 7 Coefficient generation part 10 Recording medium 11 Transmission part 21, 22, 31, 32, 40, 51, 52, 60, 61, 62 , 70, 73 Comparison unit 23, 33, 53, 63 Gain selection signal generation unit 24, 25, 34, 35, 54, 55, 64, 65 Gain switching unit 26, 27, 36, 37, 56, 57, 66, 67 Multiplication unit 28, 29, 38, 39, 58, 59, 68, 69 Addition unit 41, 42, 71, 72 Control unit 203 Pedestal value selection signal generation unit 204 Pedestal value switching unit 213 Gain selection signal generation unit 214 Gain switching Unit 223 Detail amount selection signal generation unit 224 Detail amount switching unit 226 Contour correction unit

Continued on the front page F term (reference) 5C065 AA01 BB01 CC03 DD02 GG02 GG08 GG15 GG21 GG22 GG23 GG27 GG32 GG43 HH01 HH04 5C066 AA01 AA11 BA20 CA08 DA01 DC01 EA19 EB01 EC02 GA02 HA03 JA03 KC02 KD02 KE02 KG02

Claims (13)

[Claims] 1. A hue discriminating means for discriminating a hue from a video signal, a color reproduction correcting means for performing color reproduction correction on the video signal, and a color reproduction of the color correction processing means according to a discrimination output of the hue discriminating means. A video signal processing device, comprising: color reproduction correction coefficient control means for changing a correction coefficient, and performing color reproduction correction according to the hue to the video signal. 2. A hue judging means for judging a hue from a video signal, a pedestal processing means for performing pedestal processing on the video signal, and a pedestal value of the pedestal processing means variably set according to a judgment output of the hue judging means. And a pedestal value control means for performing pedestal processing corresponding to the hue to the video signal. 3. A hue judging means for judging a hue from a video signal, a level compression / expansion processing means for applying a level compression / expansion process to the video signal, and a level compression / expansion processing in accordance with the judgment output of the hue judgment means. Decompression processing level compression
A video signal processing apparatus, comprising: level compression / expansion characteristic control means for changing expansion characteristics, and performing a level compression / expansion process in accordance with the hue to the video signal. 4. A hue discriminating means for discriminating a hue from a video signal, contour emphasizing processing means for performing contour correction processing on the video signal, and a detail amount of the contour emphasizing processing means according to a discrimination output of the hue discriminating means. A video signal processing device comprising: a detail amount control means for changing the hue; and performing contour correction processing according to the hue to the video signal. 5. The video signal processing apparatus according to claim 1, wherein said hue discriminating means discriminates the hue in units of an area divided by a plurality of mutually intersecting straight lines set on a color vector diagram. . 6. A method according to claim 1, wherein the distance of the hue determined by said hue determination means from said plurality of straight lines is determined, and the color reproduction correction of said color reproduction correction means is stopped according to a result of the determination. Item 6. The video signal processing device according to Item 5. 7. The hue discriminating means compares a first color difference signal input with a first reference value, and compares a second color difference signal input with a second reference value. A second comparison unit, a gain selection signal generation unit that generates a signal for switching a plurality of gain constants based on an output of the first comparison unit and an output of the second comparison unit, and a gain selection signal generation unit , A first and second gain switching section for switching and outputting a plurality of gain constants, and a first multiplication section for multiplying the first color difference signal input by the output of the first gain switching section. And a second multiplication unit that multiplies the second color difference signal input by the output of the second gain switching unit, and adds the first color difference signal input and the output of the second multiplication unit. , A first adder that obtains a first correction output, the second color difference signal input, and the first multiplier 2. The video signal processing apparatus according to claim 1, further comprising: a second adder for adding a second output to the second output to obtain a second corrected output. 8. The hue determining means compares a first color difference signal input with a first reference value and a second color difference signal input with a second reference value. A second comparison unit, a gain selection signal generation unit that generates a signal for switching a plurality of gain constants based on an output of the first comparison unit and an output of the second comparison unit, and a gain selection signal generation unit And a first and second gain switching section for switching and outputting any one of a plurality of gain constants, and a first for multiplying the first color difference signal input by the output of the first gain switching section. , A second multiplier for multiplying the second color difference signal input by the output of the second gain switching unit, and the first color difference signal input and the second color difference signal input. A third comparison unit for comparing with a third reference value, and an output of the third comparison unit, A first control unit for controlling an output of the first multiplication unit, a second control unit for controlling an output of the second multiplication unit by an output of the third comparison unit, and a first color difference signal. The input and the output of the second control unit are added, and the first
And a second adder that adds the second color difference signal input and the output of the first controller to obtain a second corrected output. 2. The video signal processing apparatus according to claim 1, wherein: 9. The hue discriminating means compares a first color difference signal input with a first reference value and a second color difference signal input with a second reference value. A second comparing section, a third comparing section for comparing the first color difference signal input with the second color difference signal input, and a plurality of outputs based on outputs of the first, second, and third comparing sections. A gain selection signal generator for generating a signal for switching the gain constant of the first and second gain constants, and a first and second gain switcher for switching and outputting any one of a plurality of gain constants based on an output signal of the gain selection signal generator; A first multiplier for multiplying the first color difference signal input by the output of the first gain switching unit; and a second multiplier for multiplying the second color difference signal input by the output of the second gain switching unit. 2, the first color difference signal input and the output of the upper second multiplier are added, A first adder for obtaining a corrected output of
2. The image according to claim 1, further comprising a second adder that adds the second color difference signal input and the output of the first multiplier to obtain a second corrected output. Signal processing device. 10. The hue determination means includes: a first comparison unit that compares a first color difference signal input with a first reference value;
A second comparison unit that compares the color difference signal input of the first color difference signal with a second reference value, a third comparison unit that compares the first color difference signal input with the second color difference signal input, and the first and second color difference signal inputs. A gain selection signal generator for generating a signal for switching a plurality of gain constants based on an output of the third comparator, and a gain selection signal generator for switching one of the plurality of gain constants based on an output of the gain selection signal generator. 1. a second gain switching section; a first multiplication section for multiplying the first color difference signal input by the output of the first gain switching section; a second color difference signal input; A second multiplying unit that multiplies the output of the gain switching unit, a fourth comparing unit that compares a difference between the first color difference signal input and the second color difference signal input with a third reference value, A first control unit that controls an output of the first multiplication unit by an output of the fourth comparison unit; The output of the fourth comparison unit is used to add the second control unit that controls the output of the second multiplication unit, the first color difference signal input, and the output of the second control unit. A first adder for obtaining a first corrected output; and a second adder for adding the second color difference signal input and the output of the first controller to obtain a second corrected output. 2. The video signal processing device according to claim 1, wherein 11. An image pickup apparatus comprising: an image pickup means; and the video signal processing device according to claim 1. Description: 12. An imaging apparatus according to claim 11, further comprising means for recording an output of said video signal processing device. 13. The imaging device according to claim 11, further comprising means for transmitting an output of said video signal processing device.