JPH0783483B2 - Output control device for electronic still camera - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic still camera, in particular, an exposure and a gain so as to make the output level of a color video signal obtained from a solid-state image pickup device thereof constant and to adjust the white balance of the color video signal. The present invention relates to an output control device for controlling.

BACKGROUND ART As its name implies, an electronic still camera can obtain a video signal of only one field or one frame exposed by opening a shutter. In order to obtain a proper reproduced image, that is, a visually natural reproduced image, proper exposure and proper white balance adjustment are required. With an electronic still camera,
Proper exposure and proper white balance must always be obtained for such a one-shot video signal. Proper exposure means that the luminance signal or G signal obtained from the solid-state imaging device used has a substantially constant level without depending on the light intensity of the field. In addition, the appropriate white balance adjustment is to control so that the levels of RGB three-color signals in an achromatic image become substantially equal.

Therefore, in the exposure control of electronic still cameras, a method similar to that of conventional silver salt film still cameras, for example, the transmitted light of a shooting lens is measured by a photodiode, and the shutter and aperture values are adjusted accordingly, and solid-state imaging is performed. A method of giving a proper exposure to a device is used. For white balance adjustment, a method of adjusting the amplifier gain of the RGB video signal by detecting the component ratio of RB color light with a color temperature detector, which is used in some video cameras, is adopted. There is.

In a video movie camera, normally, an automatic iris that feeds back from the video signal to control the aperture value so that the output level of the video signal is constant, and an automatic white balance that feedback controls the amplifier gain so that the output level of the RGB signal becomes uniform. Are using. However, with an electronic still camera, quick response is required to obtain one shot image,
Such a feedback control system for movies cannot be used.

Solid-state imaging devices such as charge-coupled devices (CCD) used as imaging devices in electronic still cameras have a narrower dynamic lens than ordinary silver halide photographic film, and the solid-state imaging device and photometric photodiode are different in G depending on the color temperature. Since the sensitivity of the signal or brightness signal is different, the brightness obtained from the solid-state imaging device can be obtained by simply measuring the transmitted light of the shooting lens to the photodiode and adjusting the shutter and aperture values accordingly to control the exposure. The signal or G signal could not be constant.

For example, photometric photodiodes have different photosensitivity characteristics from solid-state imaging devices such as CCDs. 5 and 6 show that in the case of a silicon photodiode,
The difference due to the color density of the output of the CCD sensor when the output of the auto iris sensor is made constant is shown.

As can be seen from FIG. 5, the output of the G signal changes depending on the change of the color density. For example, when the color temperature is low at about 3000 ° K, the output of the CCD sensor is low because the sensitivity of the G signal is low.

Further, as can be seen from FIG. 6, the luminance signal Y (0.3R + 0.
59G + 0.11B) output (dashed-dotted line) also changes due to changes in color density. When the color density is low at around 3000 ° K, the output is low because the sensitivity of the CCD sensor luminance signal is low.

Therefore, in the method of adjusting the values of the shutter and the aperture according to the photometric value of the photometric element, for example, the photodiode, depending on the bias of the spectral component of the incident light from the field,
In some cases, the level of the G signal or the luminance signal of the output signal from the CCD image pickup device was not adjusted to a constant appropriate value, and thus a video signal representing a good image could not be obtained.

For example, if the color density is about 3000 ° K, the sensitivity of the CCD image pickup device is low, so even if the values of the shutter and the aperture are adjusted so that the G signal or the luminance signal becomes constant according to the photometric value of the photometric element. , The output of the G signal or the luminance signal from the CCD image pickup device becomes low and is not constant.

On the other hand, in the conventional white balance adjustment method, R of G signal among R color signals obtained from the solid-state imaging device is used.
Some have adjusted the amplifier gains of the R signal and the B signal so that the integrated levels of the signal and the B signal are substantially equal. For example, the R signal and the B signal of the three separated color signals RGB obtained from the solid-state imaging device are input to the variable gain amplifier, the average level of the output signal is monitored at the output side, and the difference between the two is detected. The gains of both variable gain amplifiers are adjusted according to the difference thus detected, and this feedback is repeated so that the integrated levels of the R signal and the B signal become substantially equal. As can be seen from this, the white balance adjustment method corrects the level of the RB signal with the G signal as a reference.

However, the sensitivity of the G signal of the solid-state imaging device is not constant because it depends on the color temperature as described above with respect to the output of the photodiode. Therefore, it is necessary to adjust the output of the G signal to be constant in consideration of the color temperature, and to correct the level of the RB signal with the G signal that is made constant as a reference, but to make the G signal constant. For example, if the exposure amount is controlled, the sensitivity due to the color density of the RB signal also changes due to the change in the exposure amount, so the correction amount of the RB signal for white balance adjustment also changes, so that an appropriate white balance can be obtained. could not.

Aim The present invention eliminates the drawbacks of the prior art as described above, eliminates the uneven output due to the difference in the sensitivity characteristics with respect to the color temperature of the side light element and the solid-state imaging device, and adjusts the white balance appropriately. Therefore, it is an object of the present invention to provide an output control device that controls the exposure and gain of an electronic still camera.

DISCLOSURE OF THE INVENTION According to the present invention, there is provided an output control device for controlling an output signal level and a white balance of an electronic still camera that captures a field by a solid-state imaging device to form a color video signal representing an image of the field. , An exposure control means for controlling the exposure amount of the electronic still camera, a variable amplification means for amplifying each separated color signal of the color video signal and adjusting an amplification gain for each separated color signal, and Light detecting means for receiving the incident light and outputting a first signal according to the amount of the incident light, and color temperature detecting means for measuring the color density of the object field and outputting a second signal according to the color temperature. And the first and second
Control means for controlling the exposure control means and the variable amplification means according to the signal of the above, and the control by the control means is the difference in sensitivity from the light detection means and the white balance due to the incident light amount and color temperature of the solid-state imaging device. The output of the electronic still camera is kept constant and the white balance is adjusted so as to compensate for the change in

Description of Embodiments An embodiment of an output control device of an electronic still camera according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, an electronic still camera to which an embodiment of an output control device according to the present invention is applied has an imaging optical system 10, and the optical system 10 includes an imaging lens 12, a diaphragm 14, a beam splitter 16 and a shutter. 18 is the optical axis of the lens 12 as shown
It is arranged on 20. Behind the shutter 18, a solid-state imaging device 22 such as a CCD is arranged.

The imaging lens 12 is an imaging cell array of the solid-state imaging device 22.
An image of the object scene is formed on 24. The diaphragm 14 is an imaging cell array
It is an exposure adjustment mechanism that adjusts the amount of light incident on the 24
The diaphragm drive unit 28 drives the narrowing as shown in FIG. The beam splitter 16 is arranged at 45 ° with respect to the optical axis 12 and splits a part 30 of the incident light from the lens 12.
At the tip of the branched light 30, a photodetector element 36 is passed through a lens 32.
Is provided. The shutter 18 is an exposure mechanism that exposes the imaging cell array 24, and its opening / closing is controlled by the shutter drive unit 40 as indicated by a dotted line 38.

The photodetector element 36 is a photodiode in this embodiment, and is connected to the input of the logarithmic image amplifier 42. Lens 32
Converges the branched light 30 on the light receiving portion of the photodetector element 36. As a result, the photodetector element 36 performs the TTL-side light function of exhibiting a conduction state according to the amount of light incident on the imaging lens 12.

The solid-state imaging device 22 is a CCD color imaging device in this embodiment, the drive input 44 is connected to the drive signal output of the synchronization generation circuit 46, and the video signal output 48 is connected to the color separation gain adjustment unit 50. There is. The sync signal generation circuit 46 has a reference oscillator that runs at a stable frequency, and outputs the horizontal and vertical drive clocks required for driving the solid-state imaging device 22 to the output 44 and the horizontal and vertical sync signals to its output 52. Output. The solid-state imaging device 22 accumulates electric charges according to the subject image exposed in the imaging cell array 24 by opening the shutter 18, and outputs a color video signal according to the electric charges in response to the driving clock from the driving input 44. Output to.

As shown in FIG. 2, the color separation gain adjusting section 50 amplifies the color video signal input from the solid-state imaging device 22 to the input 48 and responds to the synchronization signal supplied from the synchronization generating circuit 46 to the synchronization input 52. In this embodiment, the pre-amplification color separation circuit 120 for separating the color input video signal into RGB three-separated color signals is provided. From the circuit 120, the R signal is output to the output 122R, the G signal is output to the output 122G, and the B signal is output to the output 122B.

These outputs 122R, 122G and 122B are connected to variable gain amplifiers 124R, 124G and 124B, respectively. The variable gain amplifiers 124R, 124G, and 124B have their gains independently variable, and can be set from the overall control unit 58 through the control lines 56R, 56G, and 56B included in the control line 56 from the overall control unit 58. Variable gain amplifiers 124R, 124G and 124B
Respectively amplifies the video signal with a gain of a value set for each and outputs it to the corresponding outputs 54R, 54G and 54G.

The output 54 of the color separation gain adjustment unit 50 is connected to the input of the matrix circuit 60. In the present embodiment, the matrix circuit 60 uses the three-color signal RGB input from the color separation gain adjustment unit 50,
It is a functional unit that forms a luminance signal Y and color difference signals RY and BY and outputs them at an output 62. Luminance signal Y
Is created by synthesizing the incident light components of these three colors by a predetermined synthesis rule, for example, the synthesis rule Y = 0.11B + 0.59G + 0.30R. The color difference signals RY and BY are output in scanning line order.

The logarithmic amplifier 42 is an amplifier that logarithmically compresses the output signal from the photodetector 36 and outputs the output signal to its output 64. The output 64 is connected to the input port of the auto iris (AE) control unit 66. The AE control unit 66 in this embodiment has an analog-digital converter that converts the signal at the input 64 into corresponding digital data, and a processing system such as a microprocessor is advantageously used. Output port of AE controller 66
68 and 70 are connected to the diaphragm drive unit 28 and the shutter drive unit 40, respectively.

The AE control unit 66 outputs a signal representing the amount of light measured by the light detection element 36 to the overall control unit 58, and the diaphragm drive unit 28 according to the signal representing the corrected amount of light sent from the overall control unit 58 as described later. And a control function unit that controls the shutter drive unit 40 and realizes an automatic exposure function that controls the exposure of the imaging cell array 24.

Each unit of these devices is controlled by the overall control unit 58. This electronic still camera has a shutter release button 72
And its output 74 is connected to the input port of the overall controller 58. The overall control unit 58 is connected to a storage unit 130 that stores data and programs necessary for controlling this device. The storage unit 130 stores the diaphragm drive unit 28, the shutter drive unit 40, and the variable gain amplifiers 124R and 124G in accordance with the output signal 34 from the photodetector 36 and the output 76 of the color temperature detection unit 78 described later.
And a look-up table 132 for creating signals to control 124B. The overall control unit 58 and the storage unit 130 are also advantageously configured in a processing system such as a microprocessor in this embodiment, and the AE control unit 66 responds to the shutter release signal sent from the shutter release button 72 through the control line 74. , Color separation gain adjustment unit 50
And the matrix circuit 60 is controlled, and by this,
That is, the exposure of the imaging cell array 24 and the solid-state imaging device 22.
It is a control mechanism for reading the video signal from the.

The output 76 of the color temperature detector 78 is connected to the input port 76 of the overall controller 58. The color temperature detection unit 78 has a color density detection function of measuring the color temperature of the object field and outputting the data to the output 76. As shown in FIG. 3, the color temperature detection unit 78 detects the light incident on the color temperature measuring optical aperture 80 from the field through the R filter 140R and the B filter 140B by the photodiodes 142R and 142B, respectively. The R filter 140R is an optical filter that projects R light, and a B filter 140B is arranged in parallel with the R filter 140R so as to divide the optical aperture into two. The B filter 140B is an optical filter that transmits B light.

The currents flowing in the photodiodes 142R and 142B according to the incident light that has passed through the R filter 140R and the B filter 140B are logarithmically compressed by the logarithmic amplifiers 144R and 144B, and input to the differential amplifier 146. The differential amplifier 146 produces an output at its output 150 which is a function of the difference between both inputs 148R and 148B, which is input to an analog to digital converter (ADC) 152. The analog-to-digital converter 152 converts this into digital data representing the difference between the two color components R and B, and outputs it to the output 76 as the color density data of the object scene.

FIG. 4 shows the relationship between the output of the color temperature detector 78 and the color density. As shown in the figure, when the color density is high, that is, when the milled color (10 ⁵ / color density Tc) is low, the output from the color temperature detection unit 78 is high.

The overall control unit 56 reads the lookup table 132 from the storage unit 130 in accordance with the signal indicating the light amount obtained from the AE control unit 66 and the signal indicating the color temperature obtained from the color temperature detection unit 78, and Create the signals that control the aperture 14, shutter 18, and variable gain amplifiers 124R, 124G, and 124B.
The AE control unit 66 outputs a signal for controlling the driving of the shutter 14 and the shutter 18.
To the variable gain amplifiers 124R, 124G and
The signal 56 for controlling the gain of the 124B is fed to the variable gain amplifiers 124R, 12
Output to 4G and 124B.

When a signal for controlling the drive of the diaphragm 14 and the shutter 18 is created by the look-up table 132 in the overall control unit 56, a signal 64 indicating the light amount obtained from the AE control unit 66.
Is corrected by the signal 76 representing the color temperature obtained from the color temperature detection unit 78, and the diaphragm drive unit 82 is corrected based on the corrected light amount.
And the signals 68 and 70 for controlling the shutter drive unit 40 are generated.

The correction of the light quantity is performed by a look-up table composed of data as shown by the dotted line in FIG. 5, for example. As shown by the solid line in FIG. 5, the solid-state imaging device 22 has a low sensitivity of the G component when the color temperature is low. Therefore, by using the look-up table shown by the dotted line in the figure, for example, it is possible to compensate for the decrease in the sensitivity of the G signal of the CCD sensor at a low color temperature and to increase the G signal at a low color temperature, that is, Solid-state imaging device
Correct so that the amount of light incident on 22 is increased.

Therefore, for example, in the overall control unit 58, when the color temperature due to the signal from the color temperature detection unit 78 is low, the AE control unit
Correct the light intensity data sent from 66 so that it is reduced. A signal for controlling the diaphragm drive unit 28 and the shutter drive unit 40 so as to further increase the exposure amount is created according to the corrected light amount data, and is output to the AE control unit 66. As a result, the diaphragm 14 and the shutter 18 are controlled to increase the exposure amount, and the amount of light incident on the solid-state imaging device 22 increases. As shown by the solid line in FIG. 5, the solid-state imaging device 22 has a low sensitivity to the G component when the color temperature is low. Therefore, the output of the G component can be made constant by increasing the amount of incident light. it can.

The overall control unit 58 also uses the look-up table data read from the storage unit 130 according to the color temperature data obtained from the color temperature detection unit 78, and the variable gain amplifiers 124R and 124G of the color separation gain adjustment unit 50. The gain of 124B is adjusted independently for each of the three colors, so that the video signals are output at almost the same integration level for each of the RGB colors 54R, 54G and
The output is from 54B. As a result, the white balance of the video signal is adjusted. That is, the three curves 170R, 170G, and 170B in FIG. 5 are substantially the same regardless of the color temperature, and are flat curves with respect to changes in color temperature.
Variable gain amplifiers 124R, 124G and 124, such as
Adjust B gain.

In this case, the sensitivity due to the color temperature in FIG. 5 also changes due to the change in the incident light amount due to the control of the exposure amount by the diaphragm 14 and the shutter 18, and therefore the variable gain amplifiers 124R and 124G
The adjustment of the gains of 124B and 124B is made in consideration of this.

For adjustment of white balance, output of each RGB color 54R, 54
When the G and 54B are adjusted, the level of the G signal or the luminance signal described later is adjusted so that the diaphragm 14 and the shutter 18 can be adjusted.
Since it is different from the level adjusted by, the data of the lookup table 132 is set so that the G signal or the luminance signal can be made constant by eliminating this error. Therefore, the signal that controls the gain RGB of the variable gain amplifiers 124R, 124G, and 124B obtained by the look-up table 132 adjusts the white balance by equalizing the average levels of the outputs 54R, 54G, and 54B of RGB colors, and
By adjusting the white balance, the diaphragm 14 and the shutter 18 can be adjusted.
The error appearing in the exposure amount made constant by the control of 1 is also corrected.

The matrix circuit 60 is provided by the output from the solid-state imaging device 22.
Since the sensitivity of the luminance signal Y created in step 1 according to the color temperature is shown by the alternate long and short dash line in FIG. 6, when the exposure is controlled so that the luminance signal Y is constant, the color temperature is low. In this case, the decrease in the sensitivity of the CCD sensor is corrected by the look-up table 132 read from the storage unit 130 as shown by the dotted line in the same manner as in the case of the G signal, and at the same time, the correction is performed. Variable gain amplifier 124R, 12 as
It controls the gain RGB of 4G and 124B, and adjusts the white balance.

Note that FIG. 1 does not show the recording function part of the electronic still camera realized as the embodiment of the present invention, that is, the function part for recording the video signal of the output 62 on the video signal recording medium such as a video floppy. This is omitted in order to avoid complication of the drawings and description, which is not directly related to the understanding of the present invention, but in order to fulfill the function as a camera, this functional unit is also included in this embodiment. Needless to say.

The shutter release button 72 operates in a two-step stroke. First, when the button is pressed to the first stage, the overall control unit 58 responds to this and activates the AE control unit 66, and TTL photometry by the light detection element 36, color temperature detection by the color temperature detection unit 78, and diaphragm drive. Control of the diaphragm 14 by the unit 28, and shutter drive unit
The shutter 18 is controlled by 40. That is, as described above, the AE control unit 66 measures the amount of light incident from the field through the lens 12 by the photodetector element 36, and outputs the photometric value to the overall control unit 58. In addition, the color temperature detection unit 78,
The color temperature of the incident light incident through the opening 80 is detected, and the detected value is output to the overall control unit 58. As described above, the overall control unit 58 uses the lookup table data read from the storage unit 130 in response to the light amount signal from the AE control unit 66 and the color temperature signal from the color temperature detection unit 78 to open the aperture of the diaphragm 14. Or aperture value, shutter 18 opening time or exposure time, and variable gain amplifiers 124R, 124G, 124B.
Determine the gain of.

When the shutter release button 72 is pressed to the second stage,
In response to this, the overall control unit 58 controls the diaphragm drive unit 28 and the shutter drive unit 40 in accordance with the determined aperture value and exposure value, respectively, and causes the solid-state imaging device 22 to perform image capturing. The solid-state imaging device 22 accumulates electric charges according to the subject image exposed in the imaging cell array 24 by opening the shutter 18, and outputs a color video signal corresponding to the electric charges in response to the driving clock from the driving input 44. Output to 48.

The color video signal read from the solid-state imaging device 22 is amplified by the color separation gain adjusting unit 50 and decomposed into the three-color signals RGB. At this time, the overall control unit 58 causes the color temperature detection unit to
Signals 56R, 56G, 56B for independently adjusting the gain of the color separation gain adjusting section 50 according to the color temperature data obtained from 78 and the photometric value obtained from the photodetector 36.
Is being output. As a result, the color separation gain adjustment unit 50
At the output 54, the three-color signal RGB whose white balance has been adjusted is output.

The three-color signal RGB output from the color separation gain adjusting unit 50 is input to the matrix circuit 60, and the circuit 60 creates a luminance signal Y according to a predetermined synthesis rule. The matrix circuit 60 also
The color difference signals RY and BY are formed, the luminance signal Y is output to the output 62, and the color difference signals RY and BY are generated.
Are output to the output 62 in the scanning line order.

As described above, in the present embodiment, the aperture of the diaphragm 14 is determined by the look-up table data according to the light amount of the incident light detected by the photodetector 36 and the color temperature of the incident light detected by the color temperature detector 78. , The opening time of the shutter 18, and the gains of the variable gain amplifiers 124R, 124G, and 124B are determined, thereby obtaining a constant output and adjusting the white balance.

Therefore, it is possible to compensate for the difference in sensitivity between the solid-state imaging device 22 and the photodetector 36 due to the color temperature, and always obtain a constant G signal output or Y signal output from the solid-state imaging device 22 regardless of the change in the color temperature. In addition, the white balance can be accurately adjusted according to the exposure amount and the color temperature of the incident light adjusted to keep the output of the G signal or the output of the Y signal constant.

Moreover, the control of the exposure amount of the incident light and the adjustment of the gains of the variable gain amplifiers 124R, 124G, and 124B for adjusting the output of the G signal or the Y signal and the white balance, and the adjustment of the gains of the variable gain amplifiers 124R, 124G, and 124B are performed by the look-up table 132 in consideration of both. , The diaphragm 14, the shutter 18, and the variable gain amplifiers 124R, 124G, and 124B are independently controlled. Therefore, when one of the output of the G signal or the Y signal and the adjustment of the white balance is adjusted and then the other is adjusted, an error does not appear in the adjusted one.

Therefore, from the scene through the imaging lens 12 to the imaging device
Even if there is a difference in the amount of light incident on 22 or the color temperature, the level of the luminance signal Y synthesized from the G signal of the video signal or the video signal output from the solid-state imaging device 22 is made constant, and the white balance is properly adjusted. It can be adjusted and at output 62 a video signal representing a good image can be obtained.

As described above, according to the present invention, the G signal of the output signal of the solid-state image pickup device or the color signal between the image pickup element and the photometric element is adjusted so that the luminance signal synthesized by the predetermined synthesis rule from the output signal becomes constant. The difference in sensitivity is compensated, and the difference in sensitivity of color signals due to color temperature is compensated so that the white balance is adjusted.

Therefore, even if the color temperature of light entering the solid-state imaging device from the field changes, the level and white balance of the video signal output from the solid-state imaging device can be properly adjusted.

Therefore, a video signal representing a good image can be obtained, and the exposure error and the white balance error which occur in the conventional electronic still camera are minimized.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of an output control device for an electronic still camera according to the present invention, FIG. 2 is a functional block diagram showing a color separation gain adjusting section in FIG. 1, and FIG. 1 is a block diagram showing an example of the color temperature detecting section of FIG. 1, FIG. 4 is a graph showing the output characteristics of the color temperature detecting section of FIG. 3, and FIGS. 5 and 6 are of the auto iris sensor of FIG. 6 is a graph showing a change in sensitivity depending on the color temperature of the CCD sensor when the output is constant. Description of main part symbols 14 …… Aperture 18 …… Shutter 22 …… Solid-state imaging device 28 …… Aperture drive unit 36 …… Photodetector 40 …… Shutter drive unit 42 …… Logarithmic amplifier 58 …… Overall control unit 60 Matrix circuit 66 AE control unit 78 Color temperature detection unit 90,92 Logarithmic amplifier 94 Differential amplifier 130 Storage unit

Claims (6)

[Claims] 1. An output control device for controlling an output level and a white balance of the color video signal of an electronic still camera for imaging a field by a solid-state imaging device to form a color video signal representing an image of the field. In the apparatus, the exposure control means for controlling an exposure amount of the incident light from the object field to the solid-state imaging device, amplifying each separated color signal of the color video signal, and each of the separated color signals. A variable amplifying means having adjustable amplification gain, a light detecting means for receiving incident light from the object field and outputting a first signal according to the amount of the incident light, and a color temperature of the object field. A color temperature detecting means for measuring the temperature and outputting a second signal according to the color temperature; and a controlling means for controlling the exposure controlling means and the variable amplifying means according to the first and second signals. The first and And a storage unit that stores data for deriving the exposure amount by the exposure control unit and the gain to be adjusted of the variable amplification unit for each separated color signal of the color video signal using the value of the signal 2 as a parameter. The control by the control unit refers to the data of the storage unit according to the first and second signals, and based on the referred data, the solid-state imaging device according to the incident light amount and the color temperature and the solid-state imaging device. The difference in sensitivity between the light detecting means and the light detecting means is compensated by controlling the exposure amount by the exposure controlling means, and at the same time, the amplification gain is adjusted by the variable gain amplifying means to output a signal representing the brightness of the color video signal. The output of an electronic still camera characterized in that the white balance of the color video signal is adjusted so that the level is constant regardless of the color temperature. The control device. 2. The apparatus according to claim 1, wherein the control means sets the output level of the G signal of the separated color signals to be constant according to the first and second signals. An output control device characterized in that 3. The apparatus according to claim 1, wherein the electronic still camera includes matrix circuit means for forming a luminance signal from the color video signal according to a predetermined synthesis rule, and the control means includes: In response to the first and second signals,
An output control device, wherein the brightness signal output from the matrix circuit is controlled to be constant. 4. The apparatus according to any one of claims 1 to 3, wherein the control means is the second device.
Corrects the first signal with the signal of, and controls the exposure control means with the corrected first signal,
An output control device which controls the variable amplification means by the corrected first signal and the second signal. 5. The output control device according to claim 1, wherein the exposure control means controls an aperture and a shutter of the electronic still camera. . 6. The apparatus according to claim 5, wherein the data of the storage means uses the values of the first and second signals as parameters, the aperture opening amount, the exposure time of the shutter, and Table data for deriving the gain to be adjusted of the variable amplification means for each separated color signal of the color video signal, wherein the control means refers to the table data according to the first and second signals. And an output control device for controlling the diaphragm, the shutter, and the variable amplification means.