JPH05276450A - Television camera apparatus - Google Patents

Abstract

PURPOSE:To prevent flicker from being amplified by controlling shutter speed by judging whether the average value of analog video signals is set between upper and lower limit values corresponding to the shutter speed or not. CONSTITUTION:When an optical signal is inputted from an object to an optical lens 1 and an optical image is generated, an electric signal according to this optical image is outputted from a CCD 3 with electronic shutter. The output signal of the CCD 3 is sampled by a sampling circuit 4 and converted to the analog video signal. An average level detection circuit 8 is constituted as an average value calculating means to calculate the average value of outputs from the circuit 4, and the detection signal of the circuit 8 is inputted to an upper limit/lower limit level detection circuit 10 and a shutter pulse drive circuit 7. When the level of the average value of analog video signals is set in the range of upper and lower limit values at such a time, the shutter speed is maintained at designated speed.

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 which uses a fixed aperture lens and is suitable for always obtaining an appropriate level of image output according to changes in the illuminance of a subject.

[0002]

2. Description of the Related Art Conventionally, as a television camera device of this type, as disclosed in, for example, Japanese Utility Model Laid-Open No. 64-29967, a device using a CCD solid-state image pickup device with an electronic shutter is known. There is. According to this device, the signal level can be automatically adjusted by changing the brightness of the subject.

[0003]

However, in the above-described conventional television camera device with a variable shutter, when used under fluorescent lamp illumination with flicker, the effect of flicker is increased by the electronic shutter, and the shutter speed is increased. There is a problem in that the response speed of the feedback system to be controlled cannot be increased beyond the field unit and proper and stable video output cannot be obtained.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a television camera device capable of maintaining an appropriate and stable image level even under illumination with flicker.

[0005]

In order to achieve the above object, in a television camera device according to the present invention, an optical image generating means for receiving an optical signal from a subject and generating an optical image,
An image capturing unit that captures an optical image generated by the optical image generating unit according to a shutter speed, converts the optical image into an electric signal for each pixel, and a sampling unit that samples an output signal of the image capturing unit to generate an analog video signal. An amplifying means for amplifying the analog video signal generated by the sampling means, a signal processing means for generating a composite synchronizing signal based on the signal amplified by the amplifying means, and an average value of the analog video signals output from the sampling means. An average value calculation means, a level determination means for determining whether the calculated value of the average value calculation means is within a range between an upper limit value and a lower limit value corresponding to the shutter speed, and a positive determination result from the level determination means The shutter speed of the image pickup means is controlled at a specified speed when is output, and when the negative judgment result is output from the level judgment means, The degree is obtained by constituting the television camera apparatus and a shutter speed control means for controlling the shutter speed of the imaging means at different speeds.

According to a second aspect of the present invention, an optical image generating means for receiving an optical signal from a subject to generate an optical image and an optical image generated by the optical image generating means are taken in according to a shutter speed, and the optical image is pixel by pixel. An image pickup means for converting into an electric signal, a sampling means for sampling an output signal of the image pickup means to generate an analog video signal, an amplification means for amplifying the analog video signal generated by the sampling means, and an amplification means for amplifying the analog video signal. A signal processing means for generating a composite synchronizing signal based on the signal, an average value calculating means for calculating an average value of the analog video signal output from the sampling means, and a calculated value of the average value calculating means is an upper limit value corresponding to the shutter speed. The level judgment means for judging whether or not it is within the range of the lower limit value, and when the positive judgment result is output from the level judgment means, the photographing is performed at the designated speed. Controlling the shutter speed of the unit,
When a negative determination result is output from the level determination means, it is determined whether the first shutter speed control means controls the shutter speed of the image pickup means at a speed different from the designated speed, and whether the first shutter speed is in the high speed range. Shutter speed determination means for determining, a photoelectric conversion speed control means for controlling the photoelectric conversion speed of the imaging means to a speed different from a designated speed when a positive determination result is output from the shutter speed determination means, and shutter speed determination The television camera device comprises a second shutter speed control means for controlling the shutter speed of the image pickup means to a speed different from the designated speed when a positive determination result is output from the means.

[0007]

Therefore, according to the present invention, when the level of the average value of the analog video signal generated by the sampling means is within the range between the upper limit value and the lower limit value, the shutter speed is maintained at the designated speed, and the illuminance of the object is reduced. It is possible to prevent the flicker from being amplified due to the change due to the flicker and the speed of the shutter speed control system being in field units. When the shutter speed is in the high speed range, the photoelectric conversion speed of the image pickup means is controlled to a speed different from the specified speed and the shutter speed is controlled to a speed different from the specified speed, and the average of the analog video signal is flickered. Even if the value level fluctuates and goes out of the range between the upper limit value and the lower limit value, the shutter speed gradually decreases and a sudden sensitivity change does not occur.Therefore, minimize the fluctuation of the signal level due to flicker. You can

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, the television camera device includes an optical lens 1,
CCD drive circuit 2, CCD solid-state image sensor with electronic shutter 3, sampling circuit 4, amplifier 5, signal processing circuit 6, shutter pulse drive circuit 7, average level detection circuit 8, automatic gain control circuit 9, upper and lower limit level detection circuit 10, a shutter speed determination circuit 11 is provided.

The optical lens 1 is constructed as an optical image generating means for receiving an optical signal from a subject and generating an optical image. The CCD solid-state image pickup device 3 with an electronic shutter is configured as an image pickup means for taking in an optical image according to a shutter speed according to a command from the shutter pulse drive circuit 7 and converting the optical image into an electric signal for each pixel. Further, in accordance with a signal from the CCD drive circuit 2, the photoelectrically changed charges are read out from the CCD as an output. Sampling circuit 4 is a CCD with electronic shutter
The sampling means is configured to sample an electric signal from the solid-state image sensor 3 to generate an analog video signal. The amplifier 5 is configured as an amplification means for amplifying the analog video signal, and the output signal of the amplifier 5 is input to the signal processing circuit 6 and processed as a composite synchronizing signal. That is, the signal processing circuit 6 is configured as signal processing means. Further, the amplification degree of the amplifier 5 is maintained at the set level by the automatic gain control circuit 9.

The average level detection circuit 8 is configured as an average value calculation means for calculating the average value of the analog video signal output from the sampling circuit 4, and the detection signal of the average level detection circuit 8 is an upper limit / lower limit level detection circuit. 10 and the shutter pulse drive circuit 7. upper limit·
The lower limit level detection circuit 10 is configured as level determination means for determining whether or not the level detected by the average level detection circuit 8 is within the range between the upper limit value and the lower limit value.
The shutter pulse drive circuit 7 uses the upper limit / lower limit level detection circuit 10 to perform C at a specified speed when the level of the average value of the analog video signal is within the range of the upper limit value and the lower limit value.
The shutter speed control means controls the shutter speed of the CD 3, and otherwise controls the shutter speed at a speed different from the designated speed. Further, whether or not the shutter speed is in the high speed range is determined by the shutter speed determination circuit 11. When the shutter speed is in the high speed range, the photoelectric conversion speed is set to the specified speed for the CCD drive circuit 2. Command is output to the shutter pulse drive circuit 7, and a command to control the shutter speed to a speed different from the specified speed is output to the shutter pulse drive circuit 7. That is, the shutter speed determination circuit 11 and the shutter pulse drive circuit 7 constitute the second shutter speed control means, and the shutter speed determination circuit 11 and the CCD drive circuit 2 constitute the photoelectric conversion speed control means. ing.

In the above structure, when an optical signal from a subject is input to the optical lens 1 to generate an optical image, an electric signal according to this optical image is output from the CCD 3.
The output signal of the CCD 3 is sampled by the sampling circuit 4 and converted into an analog video signal. At this time, when the level of the average value of the analog video signal is within the range between the upper limit value and the lower limit value, the shutter speed is maintained at the designated speed. At this time, if the range of the upper limit value and the lower limit value is set to be larger than the fluctuation of the average value level due to the flicker of the illumination, it is possible to prevent the change of the shutter speed due to the flicker.

On the other hand, when it is determined that the shutter speed has reached the high speed range, the shutter pulse and the CCD sensor gate pulse are simultaneously controlled, and the control for making the variable control unit of the shutter speed fine is performed. This prevents flicker from abruptly changing the shutter speed even when the level of the average value of the analog video signal exceeds the range of the upper limit value and the lower limit value, and greatly changing the level of the average value of the analog video signal. You can Therefore,
The shutter speed is unlikely to change with respect to the fluctuation of the average value of the analog video signal due to the flicker, and it is possible to quickly respond to the signal level change due to factors other than the flicker.

[0014]

As is apparent from the above description, in the television camera device according to the present invention, even if the television camera with the variable shutter is used under illumination with flicker such as fluorescent lighting, the television camera device can be changed by the flicker. The shutter can be prevented from malfunctioning, and proper and stable video output can be obtained according to the illuminance of the subject.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a television camera device according to an embodiment of the present invention.

[Explanation of symbols]

 1 optical lens 2 CCD drive circuit 3 CCD solid-state image sensor with electronic shutter 4 sampling circuit 5 amplifier 6 signal processing circuit 7 shutter pulse drive circuit 8 average level detection circuit 9 automatic gain control circuit 10 upper and lower limit level detection circuit 11 shutter speed determination circuit

Claims (2)

[Claims] 1. An optical image generation unit that receives an optical signal from a subject to generate an optical image, and an optical image generated by the optical image generation unit is taken in according to a shutter speed, and the optical image is electric signal for each pixel. Image pickup means for converting into an image signal, sampling means for sampling the output signal of the image pickup means to generate an analog video signal, amplifying means for amplifying the analog video signal generated by the sampling means, and amplified by this amplifying means. A signal processing means for generating a composite synchronizing signal based on the signal, an average value calculating means for calculating an average value of the analog video signal output from the sampling means, and an upper limit of the calculated value of the average value calculating means corresponding to the shutter speed. A level determination means for determining whether or not the value is within the range between the lower limit value and the lower limit value, and designation when a positive determination result is output from this level determination means Shutter speed control means for controlling the shutter speed of the image pickup means at a speed different from the designated speed when a negative judgment result is output from the level judgment means. TV camera device. 2. An optical image generating means for receiving an optical signal from an object to generate an optical image, and an optical image generated by the optical image generating means is taken in according to a shutter speed, and the optical image is electric signal for each pixel. Image pickup means for converting into an image signal, sampling means for sampling the output signal of the image pickup means to generate an analog video signal, amplifying means for amplifying the analog video signal generated by the sampling means, and amplified by this amplifying means. A signal processing means for generating a composite synchronizing signal based on the signal, an average value calculating means for calculating an average value of the analog video signal output from the sampling means, and an upper limit of the calculated value of the average value calculating means corresponding to the shutter speed. A level determination means for determining whether or not the value is within the range between the lower limit value and the lower limit value, and designation when a positive determination result is output from this level determination means First shutter speed control means for controlling the shutter speed of the imaging means at a speed different from the designated speed when the level determination means outputs a negative determination result.
What is the shutter speed determination means for determining whether or not the first shutter speed is in the high speed range, and the designated speed for the photoelectric conversion speed of the image pickup means when a positive determination result is output from the shutter speed determination means. Photoelectric conversion speed control means for controlling different speeds, and second shutter speed control means for controlling the shutter speed of the image pickup means to a speed different from the designated speed when a positive determination result is output from the shutter speed determining means. And a television camera device having.