JP2812054B2 - TV camera device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television camera device and, more particularly, to a television camera device having a fixed depth of focus which enables image pickup with a fixed iris value of a lens.

[0002]

2. Description of the Related Art It is well known that a television camera device having a plurality of image pickup devices, that is, a color television camera device is of an RGB system. Such an RGB television camera device is generally constructed as shown in FIG. Is done.

In FIG. 2, R, G, and B color component lights of a subject image acquired by a lens 1 are separated and formed by an optical system 2, electrically converted by a corresponding imaging device 3, and gain control circuits 6 and The image signal enters the encoder 11 via the video signal processing circuit 7, where the R, G, and B color component signals are combined and output as a video signal. , The peak value and the average value of each video signal are detected, and these are used as iris control signals of the lens 1 so that the entire subject of one screen can be clearly imaged.

[0004] By the way, in imaging by a television camera device, in addition to the above-described general imaging, special imaging such as blurring the background other than the main subject may be performed. In this method, the iris value of the lens 1 is fixed to a constant value, that is, an image is captured with a constant depth of focus. However, conventionally, the illuminance of the subject is changed, or an ND filter is provided between the lens 1 and the optical system 2. A constant depth of focus state is realized by interposing the power supply 12 or changing the value of the master gain 13 of the gain control circuit 6.

[0005]

However, in the above-mentioned conventional fixed depth of focus method, it is possible to determine the range of the depth of focus to some extent, but it is difficult to obtain a desired depth of focus accurately and promptly. There is a problem.

In order to accurately and promptly obtain a desired depth of focus, it is necessary to fix a lens iris value and electrically control a video level. Therefore, if the imaging device is 1
Paying attention to the fact that one TV camera device, that is, a black-and-white TV camera device, obtains a video signal regardless of the iris of the lens by controlling the gain of the output of the image sensor with an AGC circuit,
It is conceivable to use the AGC circuit incorporated in the monochrome television camera device for each channel of the RGB television camera device. However, in this case, there is a problem that it is difficult to adjust the balance between the color component signals because the gain between the channels is varied due to the variation of the AGC circuit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a television camera device capable of fixing a desired depth of focus, which can obtain a desired depth of focus accurately and promptly.

[0008]

To achieve the above object, a television camera device according to the present invention has the following arrangement. That is, a television camera device according to the present invention includes an image sensor provided for each color component light of a subject image obtained by a lens; and an amplifier provided for each image sensor and amplifying an output of the image sensor according to a gain control signal. A video signal processing circuit provided for each gain control circuit and performing signal processing on the output of the gain control circuit; a circuit that combines the outputs of the video signal processing circuits and outputs a video signal; A video level detection circuit for detecting a video level from an output of each video signal processing circuit; and a switch provided between each image sensor and each gain control circuit, and a switch provided at one input terminal. A reference signal is applied to the other input terminal of the output of the image sensor, and the output terminal is an input terminal of the gain control circuit. A switch to be connected; a reference signal generating circuit for generating the reference signal in response to a synchronization signal; and a color component signal from an output of each video signal processing circuit when the switch selects the other input terminal. A control circuit for calculating a correction value for optimizing the balance between the two, and for holding and outputting the correction value when the switch selects one of the input terminals; and a control circuit responsive to the selection of the other input terminal by the switch. A correction circuit for outputting the synchronization signal and outputting the gain control signal based on the correction value and the output of the video level detection circuit when the switch selects one input terminal. It is characterized by the following.

[0009]

Next, the operation of the television camera device according to the present invention having the above-described structure will be described. In the present invention, first, a reference signal is input to a gain control circuit and a video signal processing circuit, and a variation in gain of the gain control circuit of each channel is detected in advance to calculate a correction value for optimizing the balance of each color component signal. Then, in actual imaging, the gain of the gain control circuit is controlled based on the output signal of the video level detection circuit which conventionally controls the iris of the lens and the correction value.

As a result, the desired depth of focus can be obtained accurately and promptly, and the output level of the video signal always becomes a specified level even if the level of the video signal input from the lens having a constant iris value changes. Therefore, it is possible to provide a television camera device suitable for special photographing with a constant depth of focus.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a television camera device according to one embodiment of the present invention. In the present invention, a reference signal generation circuit 4, a switch 5, a correction circuit 8, and a control circuit 10 are added to the configuration excluding 12 and 13 in FIG.

In FIG. 1, a lens 1 can electrically change an iris value and can manually set an iris value to a fixed value. This is the same as the conventional case. In the present invention, since the iris value is used at a constant value, an aspect in which the iris value of the lens 1 is controlled by the output of the video level detection circuit 9 is not shown in FIG.

The switch 5 is provided between the image pickup device 3 of each of the R, G, and B channels and the gain control circuit 6, and the output of the image pickup device 3 is applied to one input terminal, and the other input terminal. The output of the reference signal generation circuit 4 is applied, and the output terminal is connected to the input terminal of the gain control circuit 6.

First, when the switch 5 is manually operated to select the other input terminal, a synchronizing signal is output from the correction circuit 8 in response to the selection. Thereby, the reference signal generation circuit 4 generates a reference signal of a predetermined pattern. This reference signal is R,
The signals are input to the gain control circuits 6 of the G and B channels, and input to the control circuit 10 from the corresponding video signal processing circuit 7. The signal is also input to the video level detection circuit 9, but the operation of the video level detection circuit 9 at this time is meaningless.

Since the switch 5 selects the other input terminal, the control circuit 10 detects a variation in the gain of the gain control circuit 6 of each channel from the output of each video signal processing circuit 7 and detects the variation of each color component signal. Calculate the correction value to optimize the balance.

Next, when one of the input terminals is selected by manually operating the switch 5, the output of the image pickup device 3 of each channel is output to the video level detection circuit 9 via the corresponding gain control circuit 6 and video signal processing circuit 7. To enter. Although the signal is also input to the control circuit 10, since the switch 5 selects one input terminal, the above operation is not performed, and the correction value calculated as described above is held and output to the correction circuit 8.

The video level detection circuit 9 detects the peak value and the average value of the video signal and outputs a voltage signal of a predetermined level to the correction circuit 8 as in the prior art.

The correction circuit 8 generates and outputs a gain control signal of the gain control circuit 6 of each channel based on the output of the control circuit 10 and the output of the video level detection circuit 9.
As a result, the gain of the gain control circuit 6 is controlled so as to decrease as the level of the video signal to be captured increases, and conversely, the gain of the gain control circuit 6 increases as the level of the video signal to capture decreases. Is done.

Thus, the variation in gain is corrected in a state where the balance among the R, G, and B channels is optimally adjusted, and the output video signal of the encoder 11 is always output at a specified level. Become.

As is apparent from the above description, the gain of the gain control circuit 6 is sometimes controlled to be large. It is possible to obtain a video signal of image quality.

[0021]

As described above, according to the television camera apparatus of the present invention, first, the reference signal is input to the gain control circuit and the video signal processing circuit, and the variation of the gain of the gain control circuit of each channel is detected in advance. Then, a correction value for optimizing the balance of each color component signal is calculated.
In actual imaging, the gain of the gain control circuit is controlled based on the output signal of the video level detection circuit and the correction value, which conventionally control the iris of the lens. The output level of the video signal always becomes a specified level even if the level of the video signal input from a lens having a constant iris value changes. Therefore, there is an effect that a television camera device suitable for special photography with a constant depth of focus can be provided. By using a high-sensitivity, low-noise imaging device, there is also an effect that a high-quality video signal can always be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a television camera device according to one embodiment of the present invention.

FIG. 2 is a configuration block diagram of a conventional television camera device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens 2 optical system 3 image sensor 4 reference signal generation circuit 5 switch 6 gain control circuit 7 video signal processing circuit 8 correction circuit 9 video level detection circuit 10 control circuit 11 encoder

Claims (1)

(57) [Claims] An imaging device provided for each color component light of a subject image acquired by a lens; a gain control circuit provided for each imaging device and amplifying an output of the imaging device in accordance with a gain control signal; A video signal processing circuit provided for each gain control circuit and performing signal processing on the output of the gain control circuit; a circuit for combining the outputs of the video signal processing circuits to output a video signal; and each video signal processing circuit And a video level detection circuit for detecting a video level from the output of the television camera device. A switch provided between each image sensor and each gain control circuit, wherein an output of the image sensor is provided at one input terminal. A switch having a reference signal applied to the other input terminal and an output terminal connected to the input terminal of the gain control circuit; A reference signal generation circuit for generating the reference signal in response to a synchronization signal; and optimally balancing each color component signal from the output of each video signal processing circuit when the switch selects the other input terminal. A control circuit for calculating a correction value to be performed, and holding and outputting the correction value when the switch selects one input terminal; and controlling the synchronization signal in response to the switch selecting the other input terminal. A correction circuit for outputting the gain control signal based on the correction value and the output of the video level detection circuit when the switch selects one of the input terminals. Camera device.