JPH0522650A - Imaging device - Google Patents

Abstract

(57) [Summary] [Purpose] The main subject that seems to be in the center of the screen when a subject with a wide dynamic range, such as over-forward light and backlight, is always exposed to various subjects. It is an object of the present invention to obtain an image pickup apparatus capable of controlling the aperture so that the exposure becomes appropriate. [Structure] A plurality of kinds of screen 2-division patterns corresponding to an imaging pattern of a subject which is often present in backlight or over-illumination are set, and a video signal output from an imaging device 3 is screen-divided by the screen division circuits 8 to 10 for each pattern. The average brightness of each region is divided into two and the comparators 11 to 1 are calculated for each pattern.
3, the detection characteristic control circuit 14 detects back light and over-forward light based on the comparison result of each pattern, and changes the detection characteristic of the detection circuit 6 that drives the automatic diaphragm circuit 7 based on the detection result. I did it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aperture control and improvement of dynamic range of an image pickup device such as a video camera.

[0002]

2. Description of the Related Art FIG. 7 shows, for example, Japanese Examined Patent Publication Sho 58-32551.
It is the imaging device of the 1st prior art example shown by the gazette. In the figure, 1 is a lens, 2 is a diaphragm mechanism for limiting the amount of light, 3
Is an image sensor, 4 is a preamplifier, 7 is a diaphragm drive circuit, 16
Is a camera signal processing circuit, 17 is a video signal output terminal, 20
Is a waveform shaping circuit, 21 is a smoothing circuit, 22 is a comparison circuit, 2
Reference numeral 3 is a reference signal input terminal.

Next, the operation will be described. The light incident from the subject is condensed by the lens 1, and after the light amount is limited by the diaphragm mechanism 2, it forms an image on the image sensor 3 and is converted into an electric signal. The signal output from the image sensor 3 is amplified by the preamplifier 4 to an appropriate size and input to the waveform shaping circuit 20. The waveform shaping circuit 20, as shown in FIG.
Only the portion (hatched portion) of the video signal above a certain level Vu is taken out, the smoothing circuit 21 obtains its average value, the comparison circuit 22 compares it with the reference signal input from the reference signal input terminal 23, and the difference is found. The diaphragm mechanism 2 is controlled through the diaphragm drive circuit 7 so that it disappears.

When such control is performed, a constant level Vu
Since the information of the following signals (the dark background on the actual screen) is cut to control the aperture, like when over-exposure,
When the main subject in the center is bright and the surroundings are dark, the operation is performed so that the exposure of the main subject is appropriate. However, when the main subject is dark and the peripheral portion is bright as in the case of backlighting, malfunction occurs, and when only signals below a certain level Vu, the output of the waveform shaping circuit 20 is always constant. The aperture amount is also constant, and fine aperture control cannot be performed.

Further, as shown in FIG. 9, in the waveform shaping circuit 20, if only the portion (hatched portion) of the video signal below the constant level Vd is taken out, the constant level V is obtained.
The information of signals over d (bright background portion on the actual screen) is cut to control the aperture, so when the main subject is dark and the window or white wall is bright, as in the case of backlighting,
Operates so that the main subject is properly exposed. However, contrary to the example described above, malfunction occurs when the main subject is bright and the surroundings are dark, as in the case of over-exposure, and when only signals above a certain level Vd are used, waveform shaping is performed. The output of the circuit 20 is always constant, so that the diaphragm amount is also constant and fine diaphragm control cannot be performed.

The aperture control as described above is performed, and the signal of proper exposure is output from the video signal output terminal 17 after being subjected to gamma correction, white balance and other processing in the camera signal processing circuit 16.

FIG. 10 shows, for example, JP-A-63-30678.
It is a block circuit diagram of the imaging device of the 2nd prior art example shown by the 0th publication. In the figure, 20 is a drive circuit for driving the image sensor 3, and 51 is an A / D converter, which converts a video signal output from the camera signal processing circuit 19 into a digital signal. An image memory 52 stores one field of the A / D converted video signal.

Reference numeral 53 denotes an arithmetic circuit, which compares the through video signal output from the A / D converter 51 with the video signal of one field before output from the image memory 52 to determine whether the exposure is appropriate. Select the video signal. An addressing circuit 54 controls addresses for writing and reading data in the image memory. A control circuit 55 controls the driving of the diaphragm mechanism 2 and the image pickup device 4. A D / A converter 56 converts the digital video signal output from the arithmetic circuit 53 into an analog signal.

Next, the operation will be described. The light obtained from the subject passes through the lens 1, the amount of light is limited by the diaphragm mechanism 2, and then forms an image on the image pickup device 3 to be converted into an electric signal. Then, the diaphragm mechanism 2 and the image sensor 3 are driven by the diaphragm drive circuit 7 and the image sensor drive circuit 20 which are controlled by the control circuit 55, respectively.

The control circuit 55 operates the image pickup device 3 according to the timing chart shown in FIG. Figure 11
Is an NTSC signal as an example. As shown in FIG. 11A, one frame is an odd (ODD) field and an even (EV) field.
EN) field. The field index signal (FIG. 11B) is a signal for identifying whether each field belongs to either ODD or EVEN field. V blanking signal (Fig. 11
(C) is a signal for setting the vertical blanking period. The H (high) period corresponds to the effective screen and the L (low) period corresponds to the vertical blanking period.

The timing pulse (FIG. 11 (d)) is
It is a signal for controlling the charge storage time of the image pickup device 3, and for example, in the case of a CCD image pickup device, it is a pulse for reading the pixel output to the vertical transfer CCD. The iris gate signal (FIG. 11 (d)) is an output signal of the ODD field or EV as a video signal which is a reference for automatic exposure.
This is a signal that specifies which of the output signals of the EN field is used.

In the illustrated example, as shown in FIG. 11 (e), 1/1000 second accumulation is performed during the vertical blanking period, and the 1/1000 second accumulation signal is output during the next effective screen period. . Then, the electric charge is accumulated for substantially 1/60 seconds in the effective screen period immediately after the 1/1000 second accumulation period, and the 1/60 second accumulation signal is output in the effective screen period of the next field. In this way, the image sensor 3 operates, and signals of two types (1/1000 seconds and 1/60 seconds) of light amount are output for each field.

The signal output from the image pickup device 3 is subjected to gamma correction, white balance and other processing in the camera signal processing circuit 16 in the same manner as in the signal processing circuit of a normal video camera. The video signal output from the camera signal processing circuit 16 is converted into a digital signal by the A / D converter 51,
It is input to the arithmetic circuit 53.

On the other hand, the video signal converted into a digital signal is input to the image memory 52, and the image memory 52 is controlled by the addressing circuit 54 so that the data for one field can be obtained.
Memorize the data. That is, with respect to the signal output from the A / D converter 51, the data of the immediately preceding field is stored in the image memory 52.

The arithmetic circuit 53 performs the following processing. As mentioned earlier, ODD field and EVE
In the N field, two types of image data with different light intensity are obtained, and when a subject with a wide dynamic range is imaged in the case of backlighting, the main subject causes blackout in the ODD field, which is followed by EVEN. In the field, blackout does not occur, and on the contrary, the background causes overexposure, and in the ODD field following this, overexposure does not occur.

Therefore, in the arithmetic circuit 53, the portion of the video signal output from the A / D converter 51 that causes overexposure or underexposure is deselected for the field immediately before stored in the image memory 52. The data is interpolated and the data of two adjacent fields are combined. By performing such calculation, it is possible to obtain a video signal without overexposure or underexposure.
It is converted into an analog signal by the converter 56 and output from the video signal output terminal 17.

[0017]

Since the image pickup apparatus of the first conventional example is configured as described above, the characteristic of each waveform shaping circuit can be properly exposed only in a specific case. This is not possible, and the situation of the subject changes from moment to moment, which causes malfunctions.To prevent malfunctions, you can change the characteristics of the waveform shaping circuit for the main subject in the case of over-forward light and backlight. There is a problem in that the aperture amount becomes constant when the level is below a certain level or above a certain level.

The first aspect of the present invention has been made to solve the above-mentioned problems, and it is possible to always perform proper exposure for various subjects and to provide a subject with a wide dynamic range such as over-forward light and backlight. An object of the present invention is to obtain an image pickup apparatus capable of controlling the aperture so that the main subject, which is considered to be in the center of the screen, can be properly exposed even when the image is captured.

As described above, the dynamic range improvement in the image pickup apparatus of the second conventional example is configured such that the shutter operation of the image pickup element is used as the means for changing the exposure and the special image pickup element is driven. Therefore, when shooting under a fluorescent light, flicker occurs in the image taken by the high-speed shutter. There is a problem that two types are required. Further, since a field memory is required as an image memory, there is a problem that the memory capacity becomes large and the circuit scale becomes large when handling a high-definition video signal.

The present invention has been made to solve the above problems, and the normal image quality is deteriorated even when the image pickup device is driven by a normal driving method without using the image memory. An object of the present invention is to obtain an image pickup apparatus that can improve the dynamic range without causing the above problem.

[0021]

An image pickup apparatus according to a first aspect of the present invention sets a plurality of types of screen two-division patterns corresponding to an image pickup pattern of a subject which is often present in backlight or over-lighting, and each pattern is set. The image signal output from the image pickup device is divided into two, the average brightness is obtained for each divided area, and the comparison is made for each divided pattern. Is detected, and the detection characteristic of the automatic diaphragm circuit is changed based on the detection result.

In the image pickup device according to the invention of claim 2, the light incident from the subject through the lens is divided into two systems.
The system captures images in the normal imaging state, the other system captures images with the light amount limited, and the part with the light amount of the subject having the larger light amount exceeds the normal dynamic range is imaged with the light amount limited. In addition to the interpolation using the image pickup signal of one of the two, the exposure control is performed using a transmittance variable filter.

[0023]

In the comparator of the first aspect of the present invention, when the difference between the two outputs from the screen division circuit is equal to or higher than a predetermined level, or when the difference falls within the predetermined level, the comparator is predetermined. When the level is lower than the level, three types of voltage signals are output. The detection characteristic setting control circuit detects the back light or the over-forward light from these voltage signals, and switches the characteristics of the detection circuit so as to obtain proper exposure based on the result.

In the image pickup device according to the second aspect of the present invention, when the light amount of one of the two light beams is limited by the light transmittance variable filter, the light transmittance of the light transmittance variable filter is controlled according to the light amount of the object. . When it is detected that the dynamic range of the image sensor is exceeded from the video signal of the subject part shot in the normal imaging state, the other light amount is limited and the image is shot, and the video signal is amplified to an appropriate level. Since switching and interpolation are performed, it is possible to avoid the occurrence of overexposure and underexposure, and since the variable transmittance filter is used to limit the amount of light, the dynamic range can be further expanded.

[0025]

EXAMPLES Example 1. FIG. 1 is a block circuit diagram of an embodiment of the invention of claim 1. In the figure, 5 is a gate circuit, 6 is a detection circuit, 8, 9, 10 are first, second and third screen division circuits, 11, 12, 13 are first, second and third comparators, Reference numeral 14 is a detection characteristic control circuit for controlling the detection characteristic of the detection circuit 6, and 15 is a synchronization signal generation circuit (hereinafter referred to as "SS
G ”), the first, second, and third screen division pulses having different gate pulses and division patterns are generated.

Next, the operation will be described. Image sensor 3
The video signal output from is amplified by the preamplifier 4 to an appropriate size and input to the gate circuit 5. In the gate circuit 5, the video signal in the gate area at the center of the screen as shown in FIG. 2G is extracted by the gate pulse g input from the SSG 15 and detected by the detection circuit 6, and then by the diaphragm drive circuit 7. The diaphragm mechanism 2 is driven so that the output of the preamplifier 4 is properly exposed.

On the other hand, the output of the preamplifier 4 is also input to the screen division circuits 8 to 10, and the screen division pulse b for dividing the screen into the areas as shown in FIG.
Is input to the screen dividing circuit 8 from the SSG1 and the pulse d for dividing the screen into regions as shown in FIG.
A pulse f for dividing the screen into areas as shown in FIG. 2F is input from the SSG 15 to the screen division circuit 9 from the SSG 15 to the screen division circuit 10.

The screen division circuits 8 to 10 convert the video signal output from the preamplifier 4 into the signals shown in FIGS. 2 (b), 2 (d) and 2 (f).
As shown in, each is divided into a main area and a peripheral area,
The voltage corresponding to the average brightness of each area is output. However, if the areas of this main area and peripheral area are not equal,
When an image of a uniform brightness is picked up, these two voltages are normalized so as to be equal. Then, the screen division circuit 8 to
The two voltages output from each of the
As shown in FIG. 3, a voltage signal Vh is output when the peripheral region is very bright with respect to the main region, Vm is output when the peripheral region is of the same brightness, and Vl is output when the peripheral region is very dark. .

For example, as shown in FIG. 2A, when the person is relatively large in the center of the screen and the periphery is bright like a sky or a wall, the division of FIG. Since the dark person is squeezed and the peripheral area is squeezed by the wall and the bright part of the sky, the comparator 11 outputs the voltage Vh.

However, since the ratio of the average brightness of the main area and the peripheral area in FIGS. 2D and 2F is not so large,
The comparators 12 and 13 output the voltage Vm. Similarly,
In the case where the lower half of the screen is a dark part such as a mountain and the upper half of the screen is a bright part such as the sky as in the case of photographing a landscape as in FIG. 2C, the comparator 12 outputs the voltage Vh. The comparators 11 and 13 output the voltage Vm. If there is a small main subject in the center of the screen as shown in FIG. 2 (e) and there is a bright object such as snow or the ground around it, as in shooting at a ski resort or on the ground, the comparator 13 Voltage Vh,
The comparators 11 and 12 output the voltage Vm.

The detection characteristic control circuit 14 includes comparators 11 to 1
In response to the output result of No. 3, the detection characteristic of the detection circuit 6 is controlled as shown in Table 1.

[0032]

[Table 1]

For example, in the case of a subject as shown in FIG. 2A, the outputs of the comparators 11 to 13 are the combinations shown in Table 1A as described above, and the detection characteristic of the detection circuit 6 is Since the average value detection is set and the information of the dark portion in the center of the screen is also reflected in the detection, the detection is performed so that the exposure of the main subject in the center of the screen is appropriate.

Further, in the case of a subject as shown in FIG. 2C, the outputs of the comparators 11 to 13 are the combinations shown in Table 1C, and the detection characteristic of the detection circuit 6 is set to peak detection. Detection is performed so that the bright part such as the sky in the half has the proper exposure. However, when the brightness is evenly distributed on the screen like a normal subject, the comparator 1
The outputs of 1 to 13 are as shown in Table 1 (g), and the detection circuit 6
The detection characteristic of is set to an intermediate characteristic between the average value detection and the peak detection.

In this way, the output of the preamplifier 4 which has always been properly exposed is subjected to gamma correction, white balance and other processing in the camera signal processing circuit 16 and output from the video signal output terminal 17.

Example 2. FIG. 4 is a block circuit diagram showing an embodiment of the invention of claim 2. In the figure, reference numeral 23 denotes a first image pickup element, which is a half mirror that divides incident light into two systems, and 4 is an image of the first system light of the light split by the half mirror 23.

4a is a preamplifier, 6a is a preamplifier 4a
Detection circuit for detecting the average luminance level of the output of the, 7 is a diaphragm drive circuit for driving the diaphragm mechanism 2 according to the output level of the detection circuit 6a, 24a is a first Y / C separation circuit, the output signal of the preamplifier 4a Is separated into a luminance signal and a chrominance signal.
A high-brightness detection circuit 25 detects, from among the brightness signals output from the Y / C separation circuit 24, a signal having a voltage equal to or higher than a voltage corresponding to a brightness level at which the image sensor 3a starts to be saturated.

A transmittance variable filter 26 limits the amount of light of the second system of the light split by the half mirror 23. Reference numeral 3b is an image pickup element for picking up the light transmitted through the variable transmittance filter 26, 4b is a preamplifier, 6b is a detection circuit for detecting the peak level of the output of the preamplifier 4b, and 27 is a transmittance control circuit for the output of the detection circuit 6b. Accordingly, the transmittance of the variable transmittance filter 26 is controlled.

A second Y / C separation circuit 24b separates the signal output from the preamplifier 4b into a luminance signal and a chrominance signal. Reference numeral 28 is a gain control circuit, and 29 is a control circuit, which controls the gain of the gain control circuit 28 based on the output of the detection circuit 6 b so that the gain corresponds to the transmittance of the variable transmittance filter 26. A switch 30 is a high-intensity detection circuit 25.
The first luminance signal and the chrominance signal output from the Y / C separation circuit 24a and the gain control circuit 28 based on the detection result of
Either the second luminance signal or the chrominance signal output from is selected.

Next, the operation will be described. The light from the subject is condensed by the lens 1, the amount of light is limited by the diaphragm mechanism 2, passes through the half mirror 23, forms an image on the image pickup device 3a, is converted into an electric signal, and has a proper size by the preamplifier 4a. Is amplified to. The output of the preamplifier 4a is the detection circuit 6
The signal is detected by a, and its output is input to the diaphragm drive circuit 7 to drive the diaphragm mechanism 2 so that the output of the preamplifier 4a becomes constant.

At this time, if the detection characteristic of the detection circuit 6a is set to the average value detection characteristic such that the average brightness in the central area of the screen becomes constant as shown in FIG. The main subject that seems to be present has an appropriate exposure. However, the light or bright sky around the main subject is saturated beyond the dynamic range of the image sensor 3a, and so-called whiteout occurs.

For example, when a light amount of 400% of the reference input is incident on the image pickup device 3a as shown in FIG. 6A, the output of the image pickup device 3a is as shown in FIG. 6B. Saturation starts at 250% and is completely saturated at 300%. That is, when the input signal is between 250% and 400%, overexposure occurs.

The output of the preamplifier 4a is also input to the Y / C separation circuit 24a, separated into the luminance signal Y ₁ and the color signal C ₁ and input to the switch 30. Then, the luminance signal Y ₁
Is also input to the high brightness detection circuit 25, and this brightness signal Y ₁
Is "H" when exceeds a preset specific voltage corresponding to the brightness level at which the image sensor 3a starts to be saturated.
When the voltage is (high) or lower than a specific voltage, an “L” (low) signal is output from the high brightness detection circuit 25. In the example shown above,
The luminance signal output Y ₁ of the Y / C separation circuit 24a is as shown in FIG.
As shown in FIG. 6C, when the specific voltage is set to a voltage corresponding to 250% of the reference signal level, the output of the high brightness detection circuit 25 becomes as shown in FIG. 6D.

On the other hand, the second separated by the half mirror 23
The light amount of the system is again limited by the variable transmittance filter 26, is imaged on the image sensor 3b, is converted into an electric signal, and is amplified to an appropriate size by the preamplifier 4b.
The output of the preamplifier 4b is detected by the detection circuit 6b, and its output is input to the transmittance control circuit 27 so that the output of the preamplifier 4b becomes constant.
To drive.

At this time, if the detection characteristic of the detection circuit 6b is set to so-called peak detection such that the brightest part of the entire screen, that is, the high-brightness part is properly exposed, the light around the main subject and Proper exposure will be obtained in a bright sky, etc., but the main subject will be underexposed.

The output of the detection circuit 6b is the control circuit 2
9 is also input to control the gain of the gain control circuit 28 according to the transmittance of the variable transmittance filter 26. For example, when the transmittance of the variable transmittance filter 26 is 50%, the gain of the gain control circuit 28 is doubled. Applying to the above example, the amount of light incident on the image sensor 3b is as shown in FIG. 6E, and the output of the image sensor 3b is as shown in FIG. 6F.

The output of the preamplifier 4b is also input to the Y / C separation circuit 24b and separated into a luminance signal Y ₂ and a color signal C ₂ . The luminance signal Y ₂ and the color signal C ₂ are supplied to the gain control circuit 2
8 and the gain control as described above is performed,
A signal having a level corresponding to the levels of the luminance signal Y ₁ and the color signal C ₁ is input to the switch 30. In the above example, the luminance signal Y output from the Y / C separation circuit 24b
₂ becomes like FIG.6 (g).

When the output of the high brightness detection circuit 25 is "L" (low), that is, when the light quantity of the object is within the dynamic range of the image pickup device 3a, the switch 30 outputs the brightness signal Y ₁ and the color. Select signal C ₁ and press "H"
In the case of (high), that is, when the light amount of the subject is the image pickup device 3a.
When the output of the Y / C separation circuit 24a is overexposed, the luminance signal Y ₂ and the chrominance signal output from the gain control circuit 28 which is exposed in the high luminance portion are exceeded. Select C ₂ . In the case of the previous example, the output of the switch 30 is as shown in FIG. 6 (h).

As described above, the luminance signal and the color signal without overexposure or underexposure selected by the switch 30 are processed by the camera signal processing circuit 16 such as gamma correction and white balance. Rear video signal output terminal 17
Is output from.

[0050]

According to the first aspect of the present invention, a plurality of types of screen half-division patterns corresponding to the image pickup pattern of a subject which is often present in backlight or over-forward light are set, and each pattern is output from the image pickup device. The video signal is divided into two parts, the average brightness is obtained for each divided area, and the comparison is made for each divided pattern. Based on the comparison result, the degree of backlight or over-forward light is detected, and Since it is configured to change the detection characteristics of the automatic diaphragm circuit based on the detection result, it is possible to automatically adjust the exposure to the condition of the subject even when shooting a moving image in which the condition of the subject changes from moment to moment. .

According to the invention of claim 2, the light incident from the subject through the lens is divided into two systems, one of which is imaged in a normal shooting state, and the other one is imaged with a limited light amount. Then, it is detected whether or not the light amount of the part of the subject having the larger light amount exceeds the dynamic range of the image pickup device, and when it exceeds the dynamic range, the image pickup signal of the exposure-limited one is interpolated and output. Since the exposure control is performed by using the variable transmittance filter, the dynamic range can be improved without degrading the image quality without using the image memory and the exposure control by the high-speed shutter is not performed. Therefore, there is an effect that flicker does not occur when capturing an image under a fluorescent lamp.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an image pickup device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a subject and an example of a screen division pattern in this embodiment.

FIG. 3 is a diagram showing a relationship between a difference between an average brightness of a peripheral area and an average brightness of a main area output from a division circuit in this embodiment, and an output of a comparator.

FIG. 4 is a block circuit diagram showing an image pickup apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram showing a detection range of a detection circuit 6a in this embodiment.

FIG. 6 is a diagram showing the signal amplitude at each point in this embodiment.

FIG. 7 is a block circuit diagram of an image pickup apparatus according to a first conventional example.

FIG. 8 is a video signal waveform diagram showing an operation example of the waveform shaping circuit in the conventional example.

FIG. 9 is a video signal waveform diagram showing an operation example of the waveform shaping circuit in the conventional example.

FIG. 10 is a block diagram of an image pickup apparatus according to a conventional example.

FIG. 11 is an operation timing chart of the image sensor according to the conventional example.

[Explanation of symbols]

3,3a, 3b Image sensor 5 gate circuits 6,6a, 6b Detection circuit 7 Aperture drive circuit 8, 9, 10 screen division circuit 11, 12, 13 comparator 14 Detection characteristic control circuit 15 Synchronous signal generation circuit (SSC) 23 Half mirror 24a, 24b Y / C separation circuit 25 High brightness detection circuit 26 Variable Transmittance Filter 27 Transmittance control circuit 28 Gain control circuit 30 switches

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[Procedure amendment]

[Submission date] November 7, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

FIG. 10 shows, for example, JP-A-63-30678.
It is a block circuit diagram of the imaging device of the 2nd prior art example shown by the 0th publication. In the figure, 20 is a drive circuit for driving the image pickup device 3, and 51 is an A / D converter, which converts a video signal output from the camera signal processing circuit 16 into a digital signal. An image memory 52 stores one field of the A / D converted video signal.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The timing pulse (FIG. 11 (d)) is
It is a signal for controlling the charge storage time of the image pickup device 3, and for example, in the case of a CCD image pickup device, it is a pulse for reading the pixel output to the vertical transfer CCD. The iris gate signal (Fig. 11 ( g )) is the output signal of the ODD field or the EV as the video signal which is the reference for the automatic exposure.
This is a signal that specifies which of the output signals of the EN field is used.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

In the image pickup device according to the second aspect of the present invention, when the light amount of one of the two light beams is limited by the light transmittance variable filter, the light transmittance of the light transmittance variable filter is controlled according to the light amount of the object. . When it is detected that the dynamic range of the image sensor is exceeded from the video signal of the subject part shot in the normal imaging state, the other light amount is limited and the image is shot, and the video signal is amplified to an appropriate level. because switched interpolation, overexposure and underexposure of generating wear at avoiding <br/>.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Example 2. FIG. 4 is a block circuit diagram showing an embodiment of the invention of claim 2. In the figure, 23 is
A half mirror to divide the incoming morphism light into two systems, 3a among the light divided by the half mirror 23, a first imaging device for imaging the light of the first system.

Claims (2)

[Claims] 1. A gate circuit for extracting a video signal of a predetermined portion of a screen from an output video signal of an image sensor, a detection circuit for detecting the brightness of the extracted video signal, and a control circuit controlled by the detection signal. A diaphragm drive circuit that adjusts the amount of light incident on the image sensor so that the detection signal has a set value, a synchronization signal generation circuit that generates a plurality of screen division pulses that are divided into two by different division patterns, and this screen division pulse. A screen division circuit that divides the output video signal of the image sensor into two and outputs a voltage signal corresponding to the average brightness of each area, and two voltages output from the screen division circuit for each division pattern. A plurality of comparators for comparing signals and a detector for determining the state of the subject from these comparison results and controlling the detection characteristics of the detection circuit so as to obtain an appropriate exposure state. An image pickup apparatus comprising: a wave characteristic control circuit. 2. A lens for condensing input light, a diaphragm mechanism for limiting the condensed light to an appropriate amount of light, a half mirror for dividing the incident light into two systems, and a light passing through the half mirror. And a first Y / C separation circuit that separates the output of the first image sensor into a first luminance signal and a first color signal. A high-brightness detection circuit that determines whether the first brightness signal is above or below a preset specific level, and a transmittance variable filter that limits the amount of light of the second system that has passed through the half mirror, A second image pickup device that receives light that has passed through the variable transmittance filter, a transmittance control circuit that controls the transmittance of the variable transmittance filter by the output of the second image sensor, and the second image pickup device. The output of the element is the second luminance signal and the second color signal. A second Y / C separation circuit for separating the signal into a signal and a gain control circuit for controlling the gains of the second luminance signal and the second chrominance signal by the transmittance of the transmittance variable filter; A brightness level of the first brightness signal, and a switch for switching between the brightness signal and the color signal and the second brightness signal and the color signal output from the gain control circuit based on the detection result of the high brightness detection circuit. Is below a certain level, the first switch
Second brightness signal and color signal are selected, and when the brightness level is higher than a specific level, the gain control circuit outputs the second signal.
An image pickup apparatus, which is configured to select a luminance signal and a color signal of the image signal.