JPH05316531A - Color reproduction variable circuit and imaging device - Google Patents

Abstract

(57) [Abstract] [Purpose] A color reproduction variable circuit that fully exhibits the resolution improvement effect of the RGB pixel shift method even when the RGB pixel shift method is used at the same time without deterioration due to the color reproduction correction of the resolution in the luminance signal. A color image pickup apparatus is provided which can perform color reproduction adjustment linearly and is easy to adjust. [Structure] The three primary color signals from the image pickup unit 1 are input to a color reproduction variable circuit 4, and a color reproduction correction signal from which aliasing components have been removed is added to the three primary color signals to create a new three primary color signal with changed color reproduction. Get to. Then, the process circuit 3 performs various processes such as γ process and data detection. The low-pass filter 115 is provided in the color reproduction correction signal generating means 117 of the color reproduction variable circuit 4.
Since, since the aliasing component of the color reproduction correction signal added to the three primary color signals can be removed, deterioration of resolution can be prevented. Also,
Since it is configured to adjust color reproduction before performing γ processing,
Color reproduction adjustment can be performed linearly, which facilitates adjustment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color reproduction variable circuit for changing color reproduction without degrading white balance, and an image pickup apparatus having a color reproduction variable function.

[0002]

2. Description of the Related Art A conventional color reproduction variable circuit will be described.

FIG. 10 shows an example of the configuration of a conventional color reproduction variable circuit. In FIG. 10, reference numeral 101 is a color difference calculation circuit for calculating a color difference signal from RGB three primary color signals. That is, the color difference signals RG and RB to be added to the R signal,
It is a circuit for calculating color difference signals GR and G-B to be added to the G signal and color difference signals BR and BG to be added to the B signal. 102, 103, 104, 105, 106, 1
07 is the coefficient k1, k2, k for each color difference signal.
A multiplier for multiplying 3, k4, k5, k6, 108 is R-
The output of the multiplier 102 for multiplying the G signal by the coefficient k1 and R−
Reference numeral 109 denotes an adder that adds the output of the multiplier 103 that multiplies the B signal by the coefficient k2, and 109 that multiplies the output of the multiplier 104 that multiplies the GR signal by the coefficient k3 and the G-B signal by the coefficient k4. Reference numeral 110 denotes an adder that adds the output of the multiplier 105, and 110 is a multiplier 1 that multiplies the BR signal by a coefficient k5.
Multiplier 1 for multiplying the output of 06 and the BG signal by a coefficient k6
It is an adder that adds the output of 07. Further, 111 is an adder that adds the output of the adder 108 and the R original signal, 112 is an adder that adds the output of the adder 109 and the G original signal, and 113 is the output of the adder 110. It is an adder for adding the B original signal.

The operation of the conventional color reproduction variable circuit configured as described above will be described below.

First, from the three primary color signals RGB, six color difference signals R-G, R-B, G-R, G-B, B-R and B- which are correction terms for color reproduction by the color-difference calculation circuit 101. G is calculated and output. The color difference signal RG and the coefficient k are multiplied by the multiplier 102.
1, the multiplier 103 receives the color difference signal RB and the coefficient k2, the multiplier 104 receives the color difference signal GR and the coefficient k3, the multiplier 105 receives the color difference signal GB and the coefficient k4, and the multiplier 106 receives the color difference signal B-
R and the coefficient k5, and the multiplier 107 calculates the color difference signal BG and the coefficient k.
6 and the output of the multiplier 102, which is the multiplication result of the RG color difference signal and the coefficient k1, in the adder 108 and R
-Multiplier 10 which is the multiplication result of the B color difference signal and the coefficient k2
And the output of 3 are added. Similarly, the adder 109 outputs GR
The output of the multiplier 104 which is the multiplication result of the color difference signal and the coefficient k3 and the output of the multiplier 105 which is the multiplication result of the GB color difference signal and the coefficient k4 are added, and the adder 110 adds the BR color difference signal. And the output of the multiplier 106, which is the result of multiplication by the coefficient k5, and the output of the multiplier 107, which is the result of multiplication of the BG color difference signal and the coefficient k6. Adders 108, 109,
The color reproduction correction signal output from 110 is added by the adder 11
1,112,113 are added to the three primary color signals respectively,
The new three primary color signals whose color reproduction has been changed are output as output signals.

That is, as described above, the color reproduction variable circuit carries out the operation represented by the following equation to obtain new three primary color signals with changed color reproduction.

R ′ = R + k1 * (R−G) + k2 * (R−B) G ′ = G + k3 * (G−R) + k4 * (G−B) B ′ = B + k5 * (B−R) + k6 * ( BG) Now, let us consider the state of change in color reproduction when the value of the coefficient k1 is changed from zero to a positive number, as the movement of each point on the vectorscope. When the value of the coefficient k1 is changed from zero to a positive number, as shown in FIG. 11, the straight line connecting yellow-blue where RG becomes zero becomes a boundary, and yellow where RG becomes a positive value- Red on the straight line connecting blue, each point on the magenta side moves in the direction in which the R vector increases, and green on the straight line connecting yellow-blue where RG becomes a negative value, each point on the cyan side is R The vector moves in a decreasing direction. That is, when the coefficient k1 is increased, red becomes more vivid red, and the degree of color saturation (darkness, saturation) increases.

Similarly, when the value of the coefficient k2 is changed from zero to a positive number, the points on the red and yellow sides of the straight line connecting green-magenta move in the direction in which the R vector increases, and cyan,
Each point on the blue side moves in the direction in which the R vector decreases. When the value of the coefficient k3 is changed from zero to a positive number,
The green and cyan points on the straight line connecting yellow and blue move in the direction in which the G vector increases, and the red and magenta points move in the direction in which the G vector decreases, and the value of coefficient k4 changes from zero. When changed to a positive number, the green and yellow points on the straight line connecting red and cyan move in the direction in which the G vector increases, and the blue and magenta points in the direction in which the G vector decreases. Moving. Further, when the value of the coefficient k5 is changed from zero to a positive number, each point on the blue and cyan sides of the straight line connecting green-magenta moves in the direction in which the B vector increases, and each point on the red and yellow sides moves. The point moves in the direction in which the B vector decreases, and the coefficient k
When the value of 6 is changed from zero to a positive number, each point on the blue and magenta side of the line connecting red and cyan moves in the direction in which the B vector increases, and each point on the green and yellow sides moves to B. The vector moves in a decreasing direction.

Further, for a monochrome image, since the color difference signal is zero on any coefficient for any coefficient, it can be seen that the color reproduction does not change no matter how the coefficient is changed.

Therefore, the coefficient k of the color reproduction variable circuit is
By changing the values of 1 to k6, it is possible to obtain a new three-primary-color signal in which the color reproduction of the original three-primary-color signal is varied on the six axes without impairing the white balance.

An image pickup apparatus having a conventional color reproduction variable function will be described below. FIG. 12 is a block diagram showing the arrangement of an image pickup apparatus having this conventional color reproduction variable function.
In the figure, reference numeral 1 denotes a lens, a prism, a solid-state image sensor, etc., which divides color light into R, G, and B, and R, G, and B correspond to the three primary colors by the image sensors provided in each. , G, B to obtain the three primary color signals, 2 is an image pickup unit 1
An amplifier for amplifying the RGB3 primary color signals from 3 is a process circuit unit for performing γ processing and data detection on the output signal from the amplifier 2, and 4 is a 6-axis color reproduction of the output signal from the process circuit unit 3. The above-described conventional color reproduction variable circuit for changing the color difference signals. Generally, the RGB3 primary color signals are added to the color difference calculation circuits 101 and R signals for calculating the color difference signals and the color difference signals R-G and R-B and G signals. Color difference signal G-
Coefficients k1, k2, k3, k4, k are added to the color difference signals BR and BG to be added to the R, GB, and B signals, respectively.
Multipliers 102, 103, 104, 1 for multiplying 5, k6
05, 106 and 107, color reproduction correction signals to be added to the R signal from the outputs of the multipliers 102 and 103, color reproduction correction signals to be added to the G signal from the outputs of the adder 108, multiplier 104 and multiplier 105 , An adder 110 that obtains a color reproduction correction signal to be added to the B signal from the outputs of the multipliers 106 and 107, and an adder 111 that adds the output of the adder 108 and the R original signal Bowl 109
Adder 112 and adder 1 for adding the output of G and the G original signal
It is composed of an adder 113 for adding the output of 10 and the B original signal, and is similar to the conventional color reproduction variable circuit. Reference numeral 5 is a matrix circuit for generating a luminance signal and the like from the three primary color signals from the color reproduction variable circuit 4, and 6 is control for performing various controls such as lens aperture control and white balance control based on the image data detected by the process circuit unit 3. It is a control unit that generates a signal.

The operation of the conventional image pickup apparatus having a variable color reproduction function configured as described above will be described below.

First, the output signals of the three primary colors of the image pickup section 1 are amplified by the amplifier 2 and supplied to the process circuit section 3. The process circuit unit 3 performs various signal processing such as γ processing and data detection on the supplied three primary color signals, and further outputs new three primary color signals whose color reproduction is adjusted by the color reproduction variable circuit 4. The three primary color signals output from the color reproduction variable circuit 4 are further converted into a luminance signal or the like by the matrix circuit 5. Further, the control unit 6 generates various control signals from the image data detected by the process circuit unit 3, and outputs the control signals to the imaging unit 1, the process circuit unit 3, and the matrix circuit unit 5,
Take control. With the configuration described above, color reproduction can be changed.

[0014]

However, the above-described conventional color reproduction variable circuit has the following problems. That is, when the number of pixels of the CCD is small, there is a technique called an RGB pixel shift method that obtains high resolution by using three image pickup plates as a resolution improvement method, but there are three primary colors obtained by using this RGB pixel shift method. When the conventional color reproduction variable circuit is used for the signal, the balance of the folding components is lost in the new three primary color signals obtained by the color reproduction variable circuit.
There was a problem that the resolution improvement effect of the B pixel shift method is adversely affected and the resolution deteriorates. This phenomenon remarkably appears especially when a monochrome image is taken.

Therefore, even in the image pickup apparatus having the conventional color reproduction variable function, when the RGB pixel shift method is used at the same time, when the color reproduction is changed by the coefficient of k1 to k6, especially when a black and white image is picked up, There is a problem that the fine pattern of the image is blurred.

Further, in the above-mentioned conventional image pickup apparatus having the color reproduction variable function, the color reproduction variable circuit is behind the process circuit section for performing the γ processing, and the color reproduction adjustment is performed linearly by the non-linear processing of the γ processing. Since it cannot be performed, there is a problem that adjustment is very difficult.

The present invention solves the above-mentioned conventional problems. Even when the RGB pixel shift method is used at the same time, the RGB
It is an object of the present invention to provide a color reproduction variable circuit and an image pickup device that sufficiently exhibit the resolution improvement effect of the pixel shift method and do not deteriorate the resolution of a luminance signal, or an image pickup device that can perform color reproduction adjustment linearly.

[0018]

In order to achieve the above object, the color reproduction variable circuit of the present invention includes a color reproduction correction signal generating means for generating a color reproduction correction signal in which aliasing components are removed from three primary color signals, and The color reproduction correction signal generating means is provided with a timing adjusting means for adjusting the timings of the reproduced color reproduction correction signal and the original three primary color signals, and an adding means for adding the generated color reproduction correction signal and the three primary color signals. The color reproduction correction signal from which the aliasing component has been removed and the timing-adjusted three primary color signals are added by the adding means, and a new three primary color signal in which the color reproduction is changed is obtained from the output of the adding means.

Further, the image pickup apparatus of the present invention uses an image pickup section for obtaining three primary color signals by using three image pickup elements, a process circuit section for performing .gamma. Processing and data detection, and a color reproduction correction for eliminating aliasing components. A color reproduction variable circuit for newly obtaining a three-primary-color signal whose color reproduction is changed by adding the signal to the three-primary-color signal, and after processing the three-primary-color signal obtained from the image pickup section by a process circuit, A color reproduction correction signal in which aliasing components are removed from the processed three primary color signals is generated and added to the three primary color signals to newly obtain a three primary color signal in which color reproduction is changed.

Further, the image pickup apparatus of the present invention uses an image pickup section for obtaining three primary color signals by using three image pickup elements, a process circuit section for performing .gamma. Processing and the like, and three color reproduction correction signals for which the aliasing component is removed. Change the color reproduction by adding to the primary color signal 3
A color reproduction variable circuit for newly obtaining a primary color signal is provided, and a color reproduction correction signal from which the aliasing component has been removed is added to the three primary color signals from the image pickup unit to generate a new three primary color signal in which color reproduction is changed. After being obtained by the color reproduction variable circuit, various processes are performed in the process circuit unit.

[0021]

According to the present invention, with the above-described structure, the aliasing component of the color reproduction correction signal added to the three primary color signals is removed, so that the color reproduction can be changed without disturbing the original balance of the aliasing components of the three primary color signals. RG because it can
It is possible to prevent deterioration due to color reproduction correction of the resolution achieved by the B pixel shift method.

Further, according to the present invention, when the color reproduction is adjusted by the coefficient of k1 to k6 and the RGB pixel shift method is used at the same time, the image in which a fine pattern is blurred can be improved by the above-described structure.

Further, according to the present invention, since the color reproduction can be adjusted linearly with the coefficients k1 to k6 by the above-mentioned structure, the color reproduction can be easily adjusted.

[0024]

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

FIG. 1 is a block diagram of a color reproduction variable circuit according to the first embodiment of the present invention. In FIG. 1, reference numeral 117 is a color reproduction correction signal generating means for generating a color reproduction correction signal in which aliasing components are removed from the three primary color signals. Reference numeral 101 designates six color difference signals R-G, R-B, G-R, G-B, which are correction items for color reproduction, from the RGB three primary color signals.
A color difference calculation circuit that calculates B−R and B−G, and a low pass filter 115 that extracts low frequency components of the color difference signals from the color difference calculation circuit 101. 102, 103, 10
4, 105, 106, and 107 are low-pass filters 115.
A multiplier 1 that multiplies the low-frequency components of the color difference signal output from each by coefficients k1, k2, k3, k4, k5, k6, and a multiplier 1 that multiplies the RG signal by the coefficient k1.
Multiplier 1 for multiplying the output of 02 and the RB signal by a coefficient k2
Is an adder for adding the output of 03, and 109 is GR
The output of the multiplier 104 for multiplying the signal by the coefficient k3 and RB
Reference numeral 110 denotes an adder that adds the output of the multiplier 105 that multiplies the signal by the coefficient k4, and 110 that multiplies the output of the multiplier 106 that multiplies the BR signal by the coefficient k5 and the output that multiplies the BG signal by the coefficient k6. It is an adder that adds the output of the device 107.
Further, reference numeral 118 is an adding means for adding the color reproduction correction signal and the three primary color signals. Reference numeral 111 is an adder for adding the output of the adder 108 and the R original signal, and 112 is an adder 109.
Is an adder for adding the output of G and the G original signal, and 113 is an adder for adding the output of the adder 110 and the B original signal. Reference numeral 116 is a timing adjustment circuit for adjusting the timings of the main system three primary color signals and the color reproduction correction signal of the correction term to be added.

The operation of the color reproduction variable circuit of the present embodiment constructed as above will be described below.

The three primary color signals input to the color reproduction variable circuit are supplied to the color difference calculation circuit 101 and the timing adjustment circuit 116. In the color difference calculation circuit 101, there are six color difference signals serving as correction terms for color reproduction, that is, the color difference signals RG and RB to be added to the R signal, and the color difference signal G to be added to the G signal.
Generate color difference signals B-R and B-G to be added to -R, G-B, and B signals. From the color difference signals generated by the color difference calculation circuit 101, the low pass filter 115 then extracts only the low frequency components of the respective color difference signals,
Further, the multiplier 102 has a low-frequency component of the color difference signal RG and a coefficient k1, the multiplier 103 has a low-frequency component of color difference RB and the coefficient k2, and the multiplier 104 has a low-frequency component of the color difference signal G-R. The component and coefficient k3, and the color difference signal G-
The low frequency component of B and the coefficient k4, the multiplier 106 multiplies the low frequency component of the color difference signal B−R and the coefficient k5, and the multiplier 107 multiplies the low frequency component of the color difference signal B−G and the coefficient k6, Further, the output of the multiplier 102, which is the multiplication result of the low frequency component of the RG color difference signal and the coefficient k1, is multiplied by the adder 108 after that, and the low frequency component of the RB color difference signal is multiplied by the coefficient k2. The resultant output of the multiplier 103 is added. Similarly, in the adder 109, the output of the multiplier 104, which is the result of multiplication of the low frequency component of the GR color difference signal by the coefficient k3, and the result of multiplication of the low frequency component of the GB color difference signal by the coefficient k4 are obtained. The output of a certain multiplier 105 is added to adder 1
In 10, the output of the multiplier 106, which is the multiplication result of the low-frequency component of the B-R color difference signal, and the coefficient k5, and the multiplier 1 which is the multiplication result of the low-frequency component of the B-G color difference signal, and the coefficient k6.
The output of 07 is added to form a color reproduction correction signal. Adder 1
The color reproduction correction signals output from 08, 109, and 110 are added to the three primary color signals before passing through the low-pass filter 115 by the adders 111, 112, and 113, respectively, and the new three primary colors whose color reproduction is changed are added. Output as a signal. At this time, since the color reproduction correction signal and the original three primary color signals are out of timing because the color reproduction correction signal passes through the low-pass filter 115, the original three primary color signals are output by the timing adjustment circuit 116. The timing is adjusted so that

In the present embodiment, a low-pass filter is added to the circuit for generating the color reproduction correction signal to remove the aliasing component of the color reproduction correction signal. Therefore, even when the RGB pixel shift method is used, the resolution is improved. Fully exerting the effect,
A color reproduction variable circuit that does not cause resolution deterioration in the luminance signal is realized.

The effect of suppressing deterioration of the resolution of the luminance signal of the present invention when the RGB pixel shift method is used will be described below.

When the RGB pixel shift method for improving the resolution by using three image pickup plates is used in the color reproduction variable circuit of the present invention, R newly generated by the color reproduction variable circuit of the present invention is used.
The GB3 primary color signal will be described in the frequency domain.

First, the structure of the RGB pixel shift method is shown in FIG. R and B are fixed to the prism by horizontally shifting the pixel period of one CCD with respect to the G CCD. At this time, the MTF characteristics up to the spatial sampling frequency of the signal and the folding component obtained from each color channel are expressed as shown in FIG. F
s indicates the spatial sampling frequency of the CCD. here,
Focusing on the luminance signal, since the folding vectors of the R and B channels are inverted with respect to the folding vector of G, the folding component of the luminance signal is reduced and the limit resolution is improved. In the NTSC system, the constitutive equation of the luminance signal is expressed as Y = 0.30 * R + 0.59 * G + 0.11 * B. Therefore, the folding component of the luminance signal remains 18% in the NTSC system. This state is shown in FIG. The smaller the residual aliasing component, the higher the limit resolution.

FIG. 4 shows the MTF characteristic of the color difference signal when the RGB pixel shift method is used. As shown in the figure, the signal components of the color difference signals cancel each other out, but since the folding component is inverted only in the G channel, the color difference signals R-G, G-R, B-G, G-. B
Is about 200% at the maximum for a monochrome image. Therefore, in the conventional color reproduction variable circuit, RG, BG,
When the color reproduction adjustment is performed by the color difference signals of GR and GB, the aliasing component of the original RG is generated in the black and white image portion.
Newly output RGB for addition to the B3 primary color signal
In the three primary color signals, the balance of the aliasing components is lost, the proportion of the residual aliasing components when the luminance signal is generated increases, and the limit resolution is lowered.

However, according to the present invention, the aliasing component included in the color difference signal is removed by the low-pass filter, and the color reproduction can be changed without losing the balance of the aliasing component included in the original RGB3 primary color signal. Even if the RGB pixel shift method is used at the same time, RG
The resolution improvement effect of the B pixel shift method can be sufficiently exerted, and a color reproduction variable circuit without resolution deterioration in the luminance signal can be realized.

The low-pass filter 115 does not have to be provided after the color difference calculation circuit 101, and may have any configuration as long as the aliasing component of the color reproduction correction signal can be removed in the process of generating the color reproduction correction signal. Good. FIG. 5 shows one configuration example in which the low-pass filter 115 is in front of the color difference calculation circuit 101, and FIG. 6 shows the low-pass filter 115 as the multiplier 10.
One configuration example after the Nos. 2 to 107, and FIG. 7 shows one configuration example in which the low-pass filter 115 is behind the adders 108 to 110. The description of the operation of each circuit is the same as that described above except that the order is different, and therefore the description thereof is omitted.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a block diagram of an image pickup apparatus having a color reproduction variable function according to the second embodiment of the present invention. In the figure, reference numeral 1 denotes a lens, a prism, a solid-state image sensor, etc.
Image sensor provided in each of the R, G, and
An image pickup unit that obtains R, G, and B three primary color signals corresponding to the three B primary colors, 2 is an amplifier that amplifies the RGB three primary color signals from the image pickup unit 1, and 3 is a γ process for the output signal from the amplifier 2, data Process circuit sections 4 for performing processes such as detection are color reproduction variable circuits for changing the color reproduction of the output signal from the process circuit section 6 on six axes. The color reproduction variable circuit 4 is the same as the color reproduction variable circuit of the first embodiment, and 117 is a color reproduction correction signal generating means for generating a color reproduction correction signal in which aliasing components are removed from the three primary color signals. Reference numeral 101 denotes color difference signals R-G, R-B, G-R, G-B from the RGB three primary color signals.
A color difference calculation circuit that calculates B−R and B−G, and a low pass filter 115 that extracts low frequency components of the color difference signals from the color difference calculation circuit 101. 102, 103, 10
4, 105, 106, and 107 are low-pass filters 115.
A multiplier 1 that multiplies the low-frequency components of the color difference signal output from each by coefficients k1, k2, k3, k4, k5, k6, and a multiplier 1 that multiplies the RG signal by the coefficient k1.
Multiplier 1 for multiplying the output of 02 and the RB signal by a coefficient k2
Is an adder for adding the output of 03, and 109 is GR
The output of the multiplier 104 for multiplying the signal by the coefficient k3 and RB
Reference numeral 110 denotes an adder that adds the output of the multiplier 105 that multiplies the signal by the coefficient k4, and 110 that multiplies the output of the multiplier 106 that multiplies the BR signal by the coefficient k5 and the output that multiplies the BG signal by the coefficient k6. It is an adder that adds the output of the device 107.
Further, reference numeral 118 is an adding means for adding the color reproduction correction signal and the three primary color signals. Reference numeral 111 is an adder for adding the output of the adder 108 and the R original signal, and 112 is an adder 109.
Is an adder for adding the output of G and the G original signal, and 113 is an adder for adding the output of the adder 110 and the B original signal. Reference numeral 116 is a timing adjustment circuit for adjusting the timings of the main system three primary color signals and the color reproduction correction signal of the correction term to be added. Reference numeral 5 is a matrix circuit for generating a luminance signal and the like from the three primary color signals from the color reproduction variable circuit 4, and 6 is control for performing various controls such as lens aperture control and white balance control based on the image data detected by the process circuit unit 3. It is a control unit that generates a signal.

The operation of the image pickup apparatus of this embodiment constructed as described above will be described below.

The three primary color output signals of the image pickup section 1 are amplified by the amplifier 2 and supplied to the process circuit section 3. Process circuit section 3
Then, the supplied three primary color signals are subjected to various signal processing such as γ processing and data detection, and output to the color reproduction variable circuit 4.
In the color reproduction variable circuit 4, the three primary color signals are supplied to the color difference calculation circuit 10
1 and the timing adjustment circuit 116, and the color difference calculation circuit 101 generates six color difference signals as correction terms for color reproduction, and then the low pass filter 115 outputs only the low frequency components of the respective color difference signals. Taken out. Further, the multiplier 102 has a low-frequency component of the color difference signal RG and a coefficient k1, the multiplier 103 has a low-frequency component of the color difference signal RB and a coefficient k2, and the multiplier 104 has a low-frequency component of the color difference signal G-R. Frequency component and coefficient k3, the color difference signal G-B in the multiplier 105
, The coefficient k4, the multiplier 106 multiplies the low frequency component of the color difference signal B−R with the coefficient k5, and the multiplier 107 multiplies the low frequency component of the color difference signal B−G with the coefficient k6.
Further, the multiplier 10 which is the multiplication result of the low-frequency component of the RG color difference signal and the coefficient k1 in the adder 108 after that.
2 and the low frequency component of the RB color difference signal and coefficient k2
And the output of the multiplier 103, which is the result of multiplication with.
Similarly, in the adder 109, the output of the multiplier 104, which is the result of multiplication of the low frequency component of the GR color difference signal by the coefficient k3, and the result of multiplication of the low frequency component of the GB color difference signal by the coefficient k4 are obtained. The output of a certain multiplier 105 is added, and an adder 110 is added.
Then, the output of the multiplier 106 which is the multiplication result of the low frequency component of the B-R color difference signal and the coefficient k5, and the multiplier 107 which is the multiplication result of the low frequency component of the B-G color difference signal and the coefficient k6.
And the output of are added to obtain a color reproduction correction signal from which the aliasing component is removed. The color reproduction correction signal output from the adders 108, 109 and 110 from which the aliasing component has been removed is the adder 1
Timing adjusting circuit 1 is provided with 11, 112 and 113, respectively.
It is added to the original three primary color signals adjusted so as to match the timing with the color reproduction correction signal by 16, and is output as a new three primary color signal whose color reproduction is changed. The three primary color signals output from the color reproduction variable circuit 4 have the folding components of the original RGB signals even when the RGB pixel shift method is simultaneously used.
Since the balance contained in the three primary color signals is maintained, when the matrix circuit 5 converts it into a luminance signal or the like, R
The resolution improvement effect of the GB pixel shift method can be sufficiently exerted. The control unit 6 generates various control signals from the image data detected by the process circuit unit 3 and outputs the control signals to the image pickup unit 1, the process circuit unit 3, and the matrix circuit unit 5 for control.

As described above, according to the present invention, R
Even when the GB pixel shift method is used at the same time, since the folded components of the three primary color signals whose color reproduction has been changed maintain the original three primary color signal balance, the color reproduction can be changed without blurring the fine pattern of the image. You can

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a block diagram of an image pickup apparatus having a color reproduction variable function according to the third embodiment of the present invention. In the figure, reference numeral 1 denotes a lens, a prism, a solid-state image sensor, etc.
Image sensor provided in each of the R, G, and
An image pickup unit that obtains R, G, and B three primary color signals corresponding to the three B primary colors, 2 is an amplifier that amplifies the RGB three primary color signals from the image pickup unit 1, and 3 is a γ process for the output signal from the amplifier 2, data Process circuit sections 4 for performing processes such as detection are color reproduction variable circuits for changing the color reproduction of the output signal from the process circuit section 6 on six axes. The color reproduction variable circuit 4 is the same as the color reproduction variable circuit of the first embodiment, and 117 is a color reproduction correction signal generating means for generating a color reproduction correction signal in which aliasing components are removed from the three primary color signals. Reference numeral 101 denotes color difference signals R-G, R-B, G-R, G-B from the RGB three primary color signals.
A color difference calculation circuit that calculates B−R and B−G, and a low pass filter 115 that extracts low frequency components of the color difference signals from the color difference calculation circuit 101. 102, 103, 10
4, 105, 106, and 107 are low-pass filters 115.
A multiplier that multiplies the low-frequency components of the color difference signals output from each by coefficients k1, k2, k3, k4, k5, and k6, and 108 is an adder that adds the output of the multiplier 102 and the output of the multiplier 103. And 109 is an adder that adds the output of the multiplier 104 and the output of the multiplier 105.
An adder 10 adds the output of the multiplier 106 and the output of the multiplier 107. Further, reference numeral 118 is an adding means for adding the color reproduction correction signal and the three primary color signals. 111 is an adder for adding the output of the adder 108 and the R original signal,
Reference numeral 112 is an adder that adds the output of the adder 109 and the G original signal, and 113 is an adder that adds the output of the adder 110 and the B original signal. Also, 116 is the main system 3
It is a timing adjustment circuit for matching the timing of the color reproduction correction signal of the correction term to be added with the primary color signal. Reference numeral 5 is a matrix circuit for generating a luminance signal and the like from the three primary color signals from the color reproduction variable circuit 4, and 6 is control for performing various controls such as lens aperture control and white balance control based on the image data detected by the process circuit unit 3. It is a control unit that generates a signal.

An important difference from the second embodiment is that the order of the process circuit section 3 and the color reproduction variable circuit 4 is reversed, that is, before the γ processing in the process circuit section 3 is performed. The point is that the color reproduction variable circuit 4 adjusts the color reproduction.

According to the configuration of the third embodiment, since the color reproduction adjustment is performed before the γ process is performed, the color reproduction adjustment is performed by k.
It can be performed linearly by the coefficient of 1 to k6, and the color reproduction can be easily adjusted.

The description of the operation of each circuit is the same as that described above except that the order is different, and therefore the description thereof is omitted.

If the color reproduction adjustment processing by the color reproduction variable circuit is performed before the γ processing, the other processing circuits may be in any order.

Also, regarding the circuit configuration of the color reproduction variable circuit, the color reproduction correction signal from which the aliasing component is removed is the original 3
Any structure may be used as long as it is a color reproduction variable circuit that obtains new three primary color signals by adding to the primary color signals.

[0045]

As described above, according to the present invention, 3
By removing the aliasing component of the color reproduction correction signal that is added to the primary color signals, the color reproduction can be varied without breaking the balance of the original aliasing components of the three primary color signals, so the RGB pixel shift method is used at the same time. Even if
The resolution improvement effect of the RGB pixel shift method is fully demonstrated,
It is possible to realize a color reproduction variable circuit that does not deteriorate due to color reproduction correction of the resolution of the luminance signal.

Further, according to the present invention, even when the RGB pixel shift method is used at the same time, since the folding components of the three primary color signals whose color reproduction is changed maintain the original three primary color signal balance, the image is not fine. It is possible to realize an image pickup apparatus having a color reproduction variable function that does not blur a rough pattern.

Further, according to the present invention, since the color reproduction adjustment can be performed linearly with the coefficients k1 to k6, the color reproduction adjustment can be easily performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a color reproduction variable circuit according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram for explaining an RGB pixel shift method.

FIG. 3 is a characteristic diagram showing MTF characteristics obtained by the RGB pixel shift method.

FIG. 4 is a characteristic diagram showing MTF characteristics of color difference signals obtained by the RGB pixel shift method.

FIG. 5 is a block diagram showing another configuration of the color reproduction variable circuit according to the first embodiment of the present invention.

FIG. 6 is a block diagram showing another configuration of the color reproduction variable circuit according to the first embodiment of the present invention.

FIG. 7 is a block diagram showing another configuration of the color reproduction variable circuit according to the first embodiment of the present invention.

FIG. 8 is a block diagram showing the arrangement of an image pickup apparatus having a color reproduction variable function according to the second embodiment of the present invention.

FIG. 9 is a block diagram showing another configuration of an image pickup apparatus having a color reproduction variable function in the third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a conventional color reproduction variable circuit.

FIG. 11 is a schematic diagram for explaining how the color reproduction changes.

FIG. 12 is a block diagram showing a configuration of an image pickup apparatus having a conventional color reproduction variable function.

[Explanation of symbols]

1 Imaging Unit 2 Amplifier 3 Process Circuit 4 Color Reproduction Variable Circuit 5 Matrix Circuit 6 Control Unit 101 Color Difference Calculation Circuit 102, 103, 104, 105, 106, 107 Multiplier 108, 109, 110, 111, 112, 113 Adder 115 Low-pass filter 116 Timing adjustment circuit 117 Color reproduction correction signal generation means 118 Addition means

Claims (4)

[Claims] 1. A color reproduction correction signal generating means for generating a color reproduction correction signal in which aliasing components are removed from the three primary color signals, and a timing adjusting means for adjusting the timing of the generated color reproduction correction signal and the original three primary color signals. The color reproduction correction signal including the generated color reproduction correction signal and the three primary color signals is added, and the timing adjustment is performed with the color reproduction correction signal from which the aliasing component obtained by the color reproduction correction signal generation means is removed. A color reproduction variable circuit, characterized in that the primary color signals are added by the adding means, and new three primary color signals whose color reproduction is changed are obtained from the output of the adding means. 2. An image pickup section for obtaining three primary color signals by using three image pickup elements, a process circuit section for performing .gamma. Processing and data detection, and a color reproduction correction signal from which aliasing components are removed are added to the three primary color signals. And a color reproduction variable circuit for newly obtaining three primary color signals whose color reproduction has been changed, the three primary color signals obtained from the image pickup unit are processed by the process circuit, and the processed three primary color signals are then processed. An image pickup apparatus characterized in that a color reproduction correction signal in which aliasing components are further removed is generated and is added to the three primary color signals to newly obtain three primary color signals with changed color reproduction. 3. An image pickup section for obtaining three primary color signals by using three image pickup elements, a process circuit section for performing γ processing and data detection, and a color reproduction correction signal from which aliasing components are removed are added to the three primary color signals. And a color reproduction variable circuit for newly obtaining three primary color signals whose color reproduction has been changed, and a color reproduction correction signal from which the aliasing component has been removed is added to the three primary color signals from the image pickup unit to perform color reproduction. An image pickup apparatus characterized in that after the new three-primary-color signals with different values are obtained by the color reproduction variable circuit, various processes are performed by the process circuit section. 4. An image pickup section for obtaining three primary color signals by using three image pickup elements, a process circuit section for performing γ processing and data detection, and a color reproduction correction signal from which aliasing components have been removed are added to the three primary color signals. The color reproduction variable circuit further includes a color reproduction variable circuit that newly obtains the three primary color signals whose color reproduction is changed, and a control unit that generates various control signals from the image data detected by the process circuit. 4. The image pickup apparatus according to claim 2, wherein the color reproduction correction signal from which the aliasing component is removed is added to obtain a new three primary color signal in which the color reproduction is changed.