JPS61245687A - Image pickup device - Google Patents

Abstract

PURPOSE:To eliminate the possibility of a failure of photographing, which is caused by forgetting to execute switching, by executing a selection of the first system by an automatic control and the second system by a fixed control, in accordance with attaching and detaching an electronic finder. CONSTITUTION:In case when photographing is executed by attaching an electronic finder 2 to a camera body 1, a low level signal is outputted from a detecting switch 22, and when a selecting switch 24 is turned off, an output of an OR circuit 23 becomes a low level, a switching intercept 18a of a switching device 18 is connected to contacts 18c, 18e, and a white balance adjustment of a set type is executed. When the selecting switch 24 is closed, a signal of a high level is outputted from the OR gate 23, the switching intercept 18a is connected to contacts 18b, 18d, and a white balance adjustment of a tracking type is executed. In case when a remote photographing is executed by detaching the electronic finder 2, the detecting switch 22 outputs a signal of a high level, the OR gate 23 outputs a high level signal irrespective of the selecting switch 24, and the white balance adjustment of the tracking type is executed.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an imaging device.

[Prior Art] □ As a conventional device of this kind, for example, there is a video camera that has two white balance adjustment methods: a setting type method and a tracking type method.

In other words, there is a setting type method in which a part of the signal photoelectrically converted by the image sensor is used as a setting signal for white balance adjustment, and a setting type method in which a part of the signal photoelectrically converted by the image sensor is used as a setting signal for white balance adjustment. There are video cameras that are equipped with two methods: a variable gain amplifier for white light, and a tracking type method that adjusts the white balance by adjusting the gain of the variable gain amplifier for blue light.

For such cameras, you can choose one of the methods depending on the shooting conditions at the time, but if you remove the electronic viewfinder from the camera body and take remote shots, the color temperature of the subject may change. There was a problem when it was stored away.

For example, if the white balance circuit at that time is a setting type, the image taken will have unnatural coloration, and to avoid this, go back to the camera body and set the white balance again. I had to either fix it or switch to an auto-tracking white balance. However, in actual shooting situations, these operations are often forgotten, and even the best shots often end in failure. Furthermore, even if you are an experienced user, you have to perform the above-mentioned cumbersome movements and operations while shooting, so conventional cameras lacked ease of use.

〔the purpose〕

The present invention has been made to solve these conventional problems, and an object of the present invention is to provide an imaging device that is easy to use and is free from the risk of failure in photographing.

〔Example〕

FIG. 1 shows a first embodiment of the invention. This example is a video camera.

In the figure, 1 is the camera body, 2 is the electronic viewfinder (E
VF), 3 is an image pickup device such as an image pickup tube or a solid-state image pickup device, which photoelectrically converts an optical signal from a subject incident through a lens, and scans the photoelectrically converted optical signal to extract a video signal. 4 is a preamplifier that inputs and amplifies this extracted video signal; 5 is a brightness/color signal separation circuit that separates the signal input from the preamplifier 4 into a brightness signal Y and a color signal C; The signal Y is output to the process circuit 9, and the other color signal C is output to the color separation circuit 6. 9 is the above-mentioned process circuit, which separates and extracts the low-range luminance signal YL from the input luminance signal Y, outputs it to the process circuits 7 and 8, and outputs it to the luminance signal Y.
is input to the encoder 11. 6 is the color separation circuit described above, which extracts and separates the R signal and B signal from the input color signal C, and outputs the R signal to the process circuit 7 and the B signal to the process circuit 8, respectively. 7 and 8 are process circuits, the former 7 outputs the color difference signal R-Yl, and the latter 8 outputs the color difference signal B-YL to the color modulation circuit 10, respectively.

10 is a color modulation circuit that outputs a color signal C, and 11 is an encoder that inputs this color signal C, converts it into an NTSC color signal, and outputs it. 12 is a scattering plate for receiving light incident from the outside at a wide angle; 13;
a and 13b are a red detection filter and a blue detection filter arranged behind them, and 14a and 14b are photodiodes arranged behind these filters 13a and 13b for photoelectrically converting red light and outputting an R signal. Photodiodes 15a and 15b that photoelectrically convert blue light and output B signals
is an amplifier, one amplifier 15a amplifies the R signal photoelectrically converted by the photodiode 14a and outputs it to the logarithm calculation circuit 16a, and the other amplifier 15b amplifies the B signal photoelectrically converted by the photodiode 14b and outputs it to the logarithm calculation circuit 16a. It is output to the arithmetic circuit 16b. A subtracter 16C subtracts the R signal and B signal logarithmically converted by the logarithmic calculation circuits 16a and 16b to obtain a color temperature signal. Reference numeral 18 denotes a switching device for switching between white balance setting type and tracking type, which directly inputs the color temperature signal obtained by subtraction, and
The signal is input after being inverted by an inverting amplifier 17.

Reference numeral 19 denotes an auto white balance circuit, which includes, for example, a comparator, a digital counter, and a DA converter. 20 is a switch, and when this is connected to the contact 21, the digital counter is activated, and the color difference signal R-YL is sent from the process circuit 7, and the color difference signal B-Y is sent from the process circuit 8.
L is input to the circuit 19, respectively. 22 is a detection switch that detects the presence or absence of the electronic finder 2, which outputs a high level signal when the electronic finder 2 is not attached, and outputs a low level signal when the electronic finder 2 is attached; The OR circuit 23 inputs this. 24 is a selection switch for selecting between tracking type and setting type white balance. The OR circuit 23 performs a logical sum depending on the presence or absence of the signal indicating whether or not the switch 24 is activated and the output signal from the detection switch 22. When the output is at a high level, the switching switch 18a of the switching device 18 and the contact 18b, 18d is connected to perform automatic tracking type white balance adjustment, and when the output is low level, the switching switch 18a of the switching device 18 and the contacts 18c, 18
e is connected to perform setting type white balance adjustment.

Next, the operation will be explained.

During normal shooting, that is, when shooting with the electronic viewfinder 2 attached to the camera body l, by operating the selection switch 24, you can decide whether to adjust the white balance to tracking type or setting type. Can be done.

Now, if we consider the case where the selection switch 24 is turned OFF, a low level signal is output to one terminal of the OR circuit 23, and a low level signal is output to the other terminal.
Since it remains attached to the camera body 1, a low level signal is output from the detection switch 22. Therefore, all the signals input to the OR circuit 23 are at a low level, and the output from the OR circuit 23 is also at a low level.

As a result, the switching piece 18a of the switching device 18 is connected to the contact 18c.
, 18e to perform setting type white balance adjustment.

White balance adjustment in this case is performed as follows. First, place a blank sheet of paper in front of the lens pattern, or cover it with a white cap, and then use the optical signal to detect the image sensor 3.
Inject it into the Then, this optical signal is separated into an R signal and a B signal, and the process circuit 7 outputs a color difference signal R-Y.
1, the process circuit 8 inputs the color difference signals B-YL to the auto white balance circuit 19, respectively. At this time, if the switch 20 is connected to the contact 21, the digital counter in the auto white balance circuit 19 starts operating, and the input color difference signals R-YL, B-Yl
The error voltage at that time controls the gain of the process circuit 7.8 so that each becomes 0. Then, the gains of the process circuits 7 and 8 are maintained at a constant value at the point when the voltage reaches O. White balance is adjusted in this way.

On the other hand, when the selection switch 24 is closed, the OR circuit 23
A high level signal is output to one terminal of the camera, and a low level signal is output to the other terminal since the electronic finder 2 is still attached. Therefore, the OR gate 23 outputs a high level signal. As a result, the switching piece 18a of the switching device 18 has contacts 18b, 1
8d to perform tracking type white balance adjustment.

Adjustment in this case is performed as follows. The signal from the object that enters the image sensor 3 through the lens is photoelectrically converted by the image sensor 3, and the video signal extracted by scanning is input to the preamplifier 4, where it is amplified and then converted into a luminance signal.
The signal is input to the color signal separation circuit 5. One of the luminance signals Y separated and extracted by the luminance/color signal separation circuit 5 is input to the process circuit 9, the low frequency luminance signal YL separated and extracted here is input to the process circuits 7 and 8, and the luminance signal Y is It is input to the encoder 11. The other color signal C separated and extracted by the luminance/color signal separation circuit 5 is input to a color signal separation circuit 6, the separated and extracted R signal is input to a process circuit 7, and the B signal is input to a process circuit 8. .

On the other hand, light from the outside irradiates the diffuser plate 12, and the diffuser plate 12
The diffused light illuminates the red light detection filter 13a and the blue light detection filter 13b. The filtered red light is converted into an R signal by the photodiode 14a and output to the amplifier 15a, and the similarly filtered blue light is converted to a B signal by the photodiode 14b and output to the amplifier 15b. The R signal and B signal amplified in the amplifiers 15a and 15b are logarithmically converted by the logarithmic calculation circuits 16a and 16b and then inputted to the subtracter 16c, and the color temperature signal obtained here is outputted to the process circuit 7. At the same time, it is output to the process circuit 8 via the inverting amplifier 17, and the gains of the process circuits 7 and 8 are changed in accordance with the change in color temperature of the light that illuminates the diffuser plate 12. Tracking type white balance adjustment is performed in this way.

Next, when the electronic finder 2 is removed from the camera body 1 to perform remote photography, the detection switch 22 outputs a high-level signal, which is input to the other terminal of the OR gate 23. When the selection switch 24 is OFF, a low level signal is input to the one terminal of the OR circuit 23, and when the selection switch 24 is ON, a high level signal is input to the one terminal of the OR circuit 23. However, orgate 23 is
Since a high level signal is output regardless of whether the selection switch 24 is ON or OFF, the switching switch 18a of the switching device 18
are connected to contacts 18b and 18d, and the tracking white balance is adjusted.

As mentioned above, in the first embodiment, when the electronic viewfinder 2 is attached to the camera body l, the white balance can be manually adjusted using either the setting type or the tracking type, which is useful for remote shooting. When the electronic viewfinder 2 is removed from the camera body 1, the white balance can be automatically adjusted using a tracking type. Therefore, there is no need to switch from the setting type to the tracking type each time remote photography is performed. This eliminates the risk of forgetting to switch and failing in photographing, unlike in the conventional case.

In addition, simply by removing the electronic viewfinder 2, it will automatically switch to the tracking type, so if the camera body l and the photographer are far apart during remote shooting, the photographer will have to go back and forth between the camera body l and the camera body l to switch to the tracking type. There is no need to perform any operations, making the camera easier to use.

FIG. 2 shows a second embodiment. This embodiment is also a video camera.

In the figure, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. Reference numeral 25 denotes a clamp circuit for fixing a reference black level, which inputs the luminance signal Y from the luminance signal Y and color signal C separation circuit 5 and outputs a signal with a constant black level. A smoothing circuit 26 is used to average the signal output from the clamp circuit 25 since the signal level during one horizontal period is not constant. Reference numeral 27 represents a power source for creating a reference voltage for automatic aperture, and 28 represents a volume for the manual iris. The iris 32 is opened and closed by changing the voltage created here. Reference numeral 29 denotes a switching device between the auto iris system and the manual iris system. When the auto iris system is used, the switching switch 29a contacts the contact 29c, and when the manual iris system is used, the switching switch 29a contacts the contact 29b. 30 is an error amplifier that compares the signal from the smoothing circuit 26 and the voltage generated by the power supply 27 and outputs the difference. Reference numeral 31 denotes an iris drive circuit, which opens and closes the iris 32 using a signal input from the error amplifier 30 or a voltage generated by the volume control 28. Reference numeral 33 denotes a selection switch for selecting between the auto iris method and the manual iris method, when it is OFF. outputs a low level signal, and when ON, outputs a high level signal.

Next, the operation will be explained.

When the electronic finder 2 is attached to the camera body l, the switch 22 outputs a low level, and the OR circuit 23 inputs this. At this time, the selection switch 33
When the switch 33 is in the OFF state, a low level signal is outputted from the switch 33 and inputted to the OR circuit 23. Therefore, the output from the OR circuit 23 becomes low level. As a result, the switching piece 29a of the switching device 29 comes into contact with the contact 29b, the voltage of the volume 28 is input to the iris drive circuit 31, and the iris 32 is driven by the manual iris method. On the other hand 1. If the switch 33 is in the ON state, a high level signal is output from the switch 33 and input to the OR circuit 23. Therefore, the output from the OR circuit 23 becomes high level. As a result, the switching piece 29a of the switching device 29 is connected to the contact 29c, and the iris 32 is driven by an auto-iris method based on the output of the error amplifier 30 with reference to the voltage output from the power supply 27.

Next, when the electronic finder 2 is removed from the camera body l, a high level signal is output from the detection switch 22 and input to the OR circuit 23. Therefore, the output of the OR circuit 23 is the ON/OFF state of the switch 33.
Regardless of the current level, the switching switch 29a of the switching device 29 is connected to the contact 29c, and the iris 32 is driven by the auto-iris method.

As mentioned above, in the second embodiment, when the electronic viewfinder 2 is attached to the camera body l,
2 is driven by the manual iris method, and when removed it is driven by the auto iris method, so
There is no need to switch from the manual iris method to the auto iris method each time you want to take remote shots. Therefore, there is no possibility of forgetting to switch and failing in photographing.

Furthermore, during remote photography, the photographer does not have to go back and forth between the camera body l and perform the above-mentioned switching operation, making the camera easier to use.

[Effects] As explained above, according to the present invention, switching between the first method and the second method is performed by attaching and detaching the electronic viewfinder, which makes it possible to take images that are easy to use and do not cause failures in shooting. You can get the equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a video camera according to a first embodiment of the invention, and FIG. 2 is a block diagram of a video camera according to a second embodiment of the invention. In the figure, l is the camera body, 2 is an electronic viewfinder, 3 is an image sensor, 4 is a preamplifier, 12 is a diffuser plate, 13a is a red detection filter, 13b is a blue detection filter, 14a
, 14b is a photodiode, 15a and 15b are amplifiers,
16a and 16b are logarithmic calculation circuits, 16c is a subtracter, 17
is an inverting amplifier, 18 is a switching device, 19 is an auto white balance circuit, 22 is a detection switch, 23 is an OR circuit,
24 is a selection switch, 27 is a power supply, 29 is a cutting device, 3
0 is an error amplifier, 32 is an iris, and 33 is a selection switch.

Claims (1)

[Claims] An imaging device characterized in that a control unit within the imaging device is configured to select a first method using automatic control and a second method using fixed control in response to attachment or detachment of an electronic viewfinder.