JPH0937146A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily recognize timing for performing exposure correction. SOLUTION: A photometric area selected by a second-order position selecting means 15 is monitored by an EVF 11 together with an image from a CCD 3. When an exposure correction execute key 18 is depressed, switches SW1 and SW2 are closed, an AE detection circuit 12 detects the exposing state of the photometric area, an exposure control circuit 13 performs control so that this exposing state can be proper and when it becomes proper, a control value is held. On the other hand, an exposure condition discrimination circuit 20 detects the difference between this exposing state and the proper exposing state and that difference is displayed on the EVF 11. Therefore, since this difference is reduced when the exposing state gets closer to the proper state, a photographer can easily and exactly recognize the timing for depressing the exposure correction execute key 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to exposure control of an image pickup device.

[0002]

2. Description of the Related Art FIG. 10 is a block diagram showing the structure of a conventional image pickup apparatus. In FIG. 10, 1 is an imaging lens group for a subject, and 2 is a diaphragm mechanism such as an iris of a diaphragm blade structure for controlling the amount of incident light and liquid crystal means for controlling the amount of transmitted light. Here, the case where the iris 2 is used is shown. Indicated by 3 is an image pickup device such as a CCD for photoelectrically converting incident light, 4 is an aperture detection means using a hall element for detecting the state of the aperture of the iris 2, and 5 is an IG meter or the like for driving the iris 2. A drive motor, 6 controls the image pickup device 3 to read out a photoelectrically converted signal, and an image pickup device control circuit for controlling a so-called electronic shutter function for controlling a signal accumulation time, and 7 photoelectrically converts by the image pickup device 3. A sampling and holding circuit for sampling a signal, 8 an automatic gain control circuit (hereinafter abbreviated as an AGC circuit) for electrically amplifying a signal, 9 a gamma correction, a color component , It was subjected to processing such as color difference matrix, a video signal processing circuit for generating a video signal of a standard television signal by adding a synchronization signal,
A video tape recorder (hereinafter abbreviated as VTR) 10 records the video signal on a magnetic tape.

Reference numeral 11 is an electronic viewfinder (hereinafter abbreviated as EVF) for monitoring the image being photographed, 12 is an AE detection circuit for detecting the exposure state of the subject from the image signal output from the AGC circuit 8, and 13 is AE detection circuit 1
Iris 2, the shutter speed of the electronic shutter controlled by the image sensor control circuit 6, based on the detection signal
An exposure control circuit that controls the amplification factor of the C circuit 8, 14 is an iris drive circuit that controls the motor 5 that drives the iris 2 according to the output of the exposure control circuit 13, and 15 is at least a part of the portion included in the video signal. A two-dimensional position selecting means having a joystick, a trackball, a mouse, a touch panel, etc. as input means for selecting, and 16 displays the image position selected by the two-dimensional position detecting means 15 as a photometric area as shown in FIG. A display circuit for outputting a display signal for performing the above, reference numeral 17 is a signal addition circuit for adding the video signal output from the video signal processing circuit 9 and the display signal output from the display circuit 16, and 18 is an exposure Exposure compensation execution key for turning on / off the compensation, 19
Is a photometry area control means for controlling the photometry area shown in FIG. 11 for detecting the exposure state of the image area corresponding to the selected position selected by the two-dimensional position selection means 15, and SW1 is a switch.

The exposure control circuit 13 includes an automatic exposure control section 13a, an exposure state determination section 13b, and a data hold section 1.
3c, AGC controller 13d, electronic shutter controller 13
e, the iris control unit 13f, and the switch SW2 are configured as illustrated.

Next, the operation will be described. If the target subject to automatic exposure control is not optimally exposed, such as underexposure due to backlit blackness or overexposure due to overexposure, the photographer should select E
While monitoring the VF 11, the two-dimensional position selection means 15 sets the two-dimensional position selection frame as a photometric area shown in FIG. A position signal indicating the position of the photometric area from the two-dimensional position selection means 15 is input to the photometric area control means 19 for detecting the exposure state of the image area corresponding to the position selected by the two-dimensional position selection means 15. Controls the photometric area.

However, at this stage, the switch SW1 is turned off.
In the FF state, the output signal from the photometric area control means 19 is A
It is not input to the E detection circuit 12. The switch SW1 is controlled by the output signal of the exposure correction execution key 18. The exposure correction execution key 18 is triggered by the operation of the photographer when the exposure correction operation is to be started after the position designation of the two-dimensional position selection frame to the position where the exposure correction is desired by the two-dimensional position selection means 15 is completed. It is one of the input means for inputting a signal. When a trigger signal is input by the exposure correction execution key 18, the switch SW1 is turned on. When the switch SW1 is turned on, the exposure state of the image area corresponding to the photometric area set by the photometric area control means 19 is AE.
It is detected by the detection circuit 12.

The automatic exposure control section 13 of the exposure control circuit 13
In a, an electronic shutter that controls the accumulation time of the iris 2 and the image pickup device 3 according to the detection signal of the AE detection circuit 12,
The exposure control parameter such as the amplification factor of the GC circuit 8 is selected and the correction amount of each parameter is determined, and the control value is calculated so as to obtain a stable and optimal exposure.

On the other hand, the trigger signal from the exposure correction execution key 18 turns on the switch SW2 of the exposure control circuit 13,
The calculation result of the automatic exposure control unit 13a is the exposure state determination unit 1
It is input to 3b. The exposure state determination unit 13b is a switch S
Only when W2 is in the ON state, it is determined whether or not the proper exposure has been obtained based on the calculation result of the automatic exposure control unit 13a. Then, when it is determined that the exposure state is appropriate, the data hold unit 1
3c outputs a control signal for turning the hold on. Further, when the switch SW2 is in the OFF state or when the result of the exposure state determination unit 13b determines that the exposure state is not proper, the control signal that outputs the data hold unit 13c to the hold OFF state is output.

The data hold unit 13c selects exposure control parameters such as an iris control value, an electronic shutter control value, and an AGC control value calculated by the automatic exposure control unit 13a in accordance with the control signal from the exposure state determination unit 13b, and each of them. Controls whether to hold the correction amount of the parameter.
In the hold-off state, the iris control value calculated by the automatic exposure control unit 13b, the electronic shutter control value, A
The selection of the exposure control parameter such as the GC control value and the correction value of each parameter are directly output to the iris control unit 13f, the electronic shutter control unit e, and the AGC control unit 13d. As a result, the correction operation is performed following the change in the video signal.

Further, in the hold ON state, the exposure control parameters such as the iris control value, the electronic shutter control value and the AGC control value at the moment when the hold control signal is output from the exposure state discriminating section 13b are selected and each parameter. The correction value is stored and the stored value is output to the iris control unit 13f, the electronic shutter control unit 13e, and the AGC control unit 13d regardless of the change in the brightness of the subject.

In this way, when the trigger signal is input from the exposure correction execution key 18, the correction operation is started so that the exposure state of the image area of the photometric area selected by the two-dimensional position selecting means 15 becomes optimum, The correction operation is continued until the exposure state determination unit 13b determines that the exposure state is optimum. When it is determined that the optimum value is obtained, the correction operation is ended and the data hold unit 13c is controlled to the hold ON state to maintain the optimum exposure control state. As a result, even if the zoom magnification fluctuates and the surrounding brightness changes, the exposure state of the subject within the photometric area selected by the two-dimensional position selecting unit 15 is optimally maintained.

As described above, in the conventional art, the photographer uses the EVF.
While looking at the monitor device such as 11, select the image area of the subject for which the optimum exposure state is desired, and then input the trigger signal at the timing at which exposure compensation is desired, the brightness state of the selected image area is detected, The exposure compensation operation is performed while determining whether the exposure state has been optimized, and when the exposure state of the selected image area is corrected to the optimum state, the exposure state is retained and these series of correction operations are performed. It is done automatically.

[0013]

However, in the above-described conventional image pickup apparatus, the photographer does not determine the timing of inputting the trigger signal by the exposure correction execution key 18 by checking the exposure status on the monitor device such as EVF. must not. However, an EVF as a monitor device is generally miniaturized so that it can be seen with one eye. Therefore, the screen size is small, and an EVF using a liquid crystal display is not sufficient in dynamic range due to colorization. For some reason, it is difficult to accurately confirm the exposure state of the subject. Therefore, it is difficult for the photographer to grasp the timing of inputting the trigger signal, and if the timing of inputting the trigger signal is incorrect, the exposure becomes extremely inappropriate,
There is a problem that the image is taken in a state different from the image intended by the photographer.

The present invention has been made by paying attention to such a problem, and after the photographer selects a desired object,
By making it possible to accurately grasp the exposure state of the subject on a monitor device such as an EVF, the photographer can easily and accurately grasp the timing at which the trigger signal is input. The purpose is to enable the person to obtain the intended video.

[0015]

According to the present invention, an image pickup means for picking up an optical image of a subject and converting it into an electric video signal, and an exposing means for exposing the optical image of the subject to the image pickup means. An exposure detecting means for detecting an exposure state of a video area including at least a part of the video signal obtained from the imaging means, and controlling the exposure of the exposure means according to the exposure state detected by the exposure detecting means. The exposure control means, the instruction means for instructing execution of the control operation of the exposure control means, and the exposure state detected by the exposure detection means after the control operation of the exposure control means is started by the instruction of the instruction means. An exposure status determination means is provided for detecting a difference between the value and a value indicating an appropriate exposure state.

[0016]

According to the above-mentioned structure, when the instruction for the exposure correction is given by the instruction means, the exposure control means controls the exposure state of the image area detected by the exposure detection means to be appropriate. Further, the exposure status determination means determines the difference between the exposure state of the image area and the proper exposure state.

Therefore, since the difference becomes smaller as the exposure state of the image area becomes an appropriate exposure state, it is possible to easily and accurately know the timing for instructing the exposure correction by the instructing means by using this difference. it can.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In FIG. 1, the portions denoted by the same reference numerals as those in the conventional example in FIG. Reference numeral 20 detects the exposure state of the object in the photometric area generated by the photometric area control means 19 by the AE detection circuit 12, and determines the difference between the exposure value indicating the exposure state and a predetermined appropriate exposure value. An exposure condition display circuit 21 for generating an exposure condition display signal for displaying the difference determined by the exposure condition determination circuit 20 on the EVF 11 and adding it to the signal addition circuit 17. is there.

Next, the operation will be described. The photographer sets a two-dimensional position selection frame as a photometric area at the position of the subject to be optimally exposed by the two-dimensional position selection means 15. A position signal indicating the position of the photometric area from the two-dimensional position selection means 15 is input to the photometric area control means 19,
The photometric area for detecting the exposure state of the image area corresponding to the position selected by the two-dimensional position selecting means 15 is controlled.

At this stage, the switch SW1 is OFF and the output signal from the photometric area control means 19 is the AE detection circuit 1
Not entered in 2. Exposure compensation execution key 18 in this state
Switch SW1 is turned on when a trigger signal is input by
Accordingly, the exposure state of the image area corresponding to the photometric area set by the photometric area control means 19 is detected by the AE detection circuit 12. The detection signal output from the AE detection circuit 12 is the automatic exposure control unit 1 in the exposure control circuit 13.
It is input to the exposure state determination circuit 20 as well as to 3a.

When the trigger signal is input, the automatic exposure control section 13a starts a correction operation so that the exposure state of the image area of the photometric area becomes optimum, and the exposure state determination section 13b determines that the exposure state becomes optimum. The correction operation is continued until the determination is made. When it is determined that the exposure state has been optimized, the correction operation is ended and the data hold unit 13c is controlled to the hold ON state to maintain the optimum exposure control state. The above operation is the same as the conventional example.

On the other hand, in the exposure situation discrimination circuit 20,
The detection signal from the AE detection circuit 12 is compared with a predetermined appropriate exposure value, and the difference is detected. The exposure status display circuit 21 displays the difference on the EVF 11 to generate an exposure status display signal for the photographer to understand. The exposure status display signal is added to the video signal and the display signal of the photometric area by the signal addition circuit 17, so that the EVF 11 can monitor it.

Next, referring to FIG. 2, FIG. 3, FIG. 4 and FIG.
An example of displaying on a monitor device such as the VF 11 will be described. FIG. 2 shows an example in which the detection signal output from the AE detection circuit 12 is displayed as a proper exposure value, which is displayed as zero. Is an example displaying that the detection signal is +1.5 steps brighter than the proper exposure value, and is an example displaying that the detection signal is -1.0 steps darker than the proper exposure value. .

FIG. 3 has the same meaning as in FIG. 2, but is an example when the display method is different. FIG. 4 is an example of the position where the display shown in the examples of FIGS. 2 and 3 is displayed together with the display of the photometric area.
FIG. 5 shows an example in which the result of comparison between the detection signal and the proper exposure value is shown by numbers together with the photometric area.

The examples of the display described here are only a part, and any other display may be used as long as the display shows the difference between the detection signal and the proper exposure value. .

According to the present embodiment, the "difference" between the exposure of the subject and the predetermined proper exposure value is displayed on the monitor device such as EVF, so that the photographer can trigger while watching the monitor device such as EVF. It is possible to easily and accurately grasp the timing of inputting a signal.

FIG. 6 is a block diagram showing the configuration of the second embodiment of the present invention. In FIG. 6, the parts designated by the same reference numerals as those in FIGS. 1 and 10 have the same functions.
Description is omitted. Reference numeral 22 indicates when the difference determined by the exposure condition determination circuit 20 exceeds a predetermined range,
That is, it is an exposure correction warning display circuit for generating a warning display signal for giving a warning when the exposure is not proper and adding it to the signal addition circuit 17.

Next, the operation will be described. Since the process of maintaining the exposed state is the same as that of the first embodiment, only the points different from the first embodiment will be described. The exposure situation determination circuit 20 compares the detection signal with a predetermined proper exposure value and detects the difference. The exposure correction warning display circuit 22 displays when the difference exceeds a predetermined range,
That is, when the exposure of the subject is not proper, a warning is displayed on the EVF 11 to generate an exposure correction warning display signal for the photographer to understand. The exposure correction warning display signal is added to the video signal and the photometric area display signal by the signal adding circuit 17, so that the EVF 11 can monitor the signal.

Next, an example of the warning display displayed on the monitor device such as the EVF 11 will be described with reference to FIGS. 7 and 8. FIG. 7 shows an example of the position where the warning display is displayed on the monitor device such as the EVF 11 and the warning display. FIG. 8 shows a case where the meaning of the warning is displayed by blinking the warning display in the photometric area. Note that the example of the warning display described here is only a part, and any form of display may be used as long as it can be recognized as a warning display.

According to the present embodiment, when the difference between the exposure of the subject and the predetermined proper exposure value exceeds a predetermined range, a warning is displayed on a monitor device such as an EVF so that the photographing is performed. A person can easily and accurately grasp the timing of inputting a trigger signal while looking at a monitor device such as an EVF.

FIG. 9 is a block diagram showing the configuration of the third embodiment of the present invention. The parts denoted by the same reference numerals as those in FIGS. 1, 6, and 10 have the same functions, and thus the description thereof will be omitted. Reference numeral 23 is an exposure correction warning sound generation circuit for generating a warning sound when the difference determined by the exposure status determination circuit 20 exceeds a predetermined range, that is, when the exposure is not proper.

Next, the operation will be described. Since the process of maintaining the exposed state is the same as that of the first embodiment, only the points different from the first embodiment will be described. The exposure situation determination circuit 20 compares the detection signal with a predetermined appropriate exposure value and detects the difference. The exposure correction warning sound generating circuit 23 generates a warning sound so that the photographer can recognize when the difference exceeds a predetermined range and the exposure of the subject becomes incorrect.

According to the present embodiment, when the difference between the exposure of the subject and the predetermined proper exposure value exceeds the predetermined range, a warning sound is generated so that the photographer can make an E
It is possible to easily and accurately grasp the timing of inputting the trigger signal while looking at the monitor device such as the VF.

[0034]

As described above, according to the present invention, it is possible for the photographer to easily and accurately know the timing for instructing exposure compensation. As a result, regardless of the performance of the monitor device such as EVF, the exposure state of the subject targeted by the photographer can be easily and optimally corrected by a simple operation, and it is always optimal for various subjects and shooting conditions. You can get a video.

Further, the difference between the exposure state of the image area and the proper exposure state is displayed by a monitor or the like, or a warning is issued when the difference exceeds a predetermined value, whereby the exposure is further facilitated. The timing for instructing the correction can be obtained.

Further, by controlling the position of the image area and displaying it, it is possible for the photographer to perform exposure compensation while monitoring all areas in the image.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a display example 1 of an exposure situation according to the first embodiment.

FIG. 3 is a configuration diagram showing a second display example of an exposure situation according to the first embodiment.

FIG. 4 is a configuration diagram showing a display position of an exposure status display example according to the first embodiment.

FIG. 5 is a configuration diagram showing a third display example of an exposure situation according to the first embodiment.

FIG. 6 is a block diagram showing a second embodiment of the present invention.

FIG. 7 is a configuration diagram showing an exposure correction warning display example 1 according to a second embodiment.

FIG. 8 is a configuration diagram showing an exposure correction warning display example 2 according to the second embodiment.

FIG. 9 is a block diagram showing a third embodiment of the present invention.

FIG. 10 is a block diagram showing a conventional imaging device.

FIG. 11 is a configuration diagram showing a display example of a conventional two-dimensional selection position.

[Explanation of symbols]

 2 Aperture mechanism 3 Imaging device 4 Aperture detection means 5 Aperture mechanism drive motor 6 Imaging device control circuit 8 Auto gain control circuit 11 Electronic viewfinder 12 AE detection circuit 13 Exposure control circuit 14 Iris drive circuit 15 Two-dimensional position selection circuit 18 Exposure correction Enter key 19 Photometric area control circuit 20 Exposure status determination circuit 21 Exposure status display circuit 22 Exposure correction warning display circuit 23 Exposure correction warning sound generation circuit SW1, SW2 switches

Claims (4)

[Claims] 1. An image pickup means for picking up an optical image of a subject and converting it into an electrical video signal, an exposing means for exposing the optical image of the subject to the image pickup means, and an image pickup means obtained from the image pickup means. Exposure detection means for detecting an exposure state of a video region including at least a part of a video signal; exposure control means for controlling the exposure of the exposure means according to the exposure state detected by the exposure detection means; An instruction means for instructing execution of a control operation of the exposure means, a value indicating an exposure state detected by the exposure detection means after starting the control operation of the exposure control means by the instruction of the instruction means, and a value indicating an appropriate exposure state And an exposure condition determining unit that detects a difference between 2. The image pickup apparatus according to claim 1, further comprising display means for displaying the difference detected by the exposure status determination means. 3. The image pickup apparatus according to claim 1, further comprising warning means for issuing a warning when the difference detected by the exposure status determination means exceeds a predetermined value. 4. The image pickup apparatus according to claim 1, further comprising control means for controlling the position of the image area detected by the exposure detection means, and display means for displaying the image area controlled by the control means.