JPH033570A - Video camera equipment - Google Patents

Abstract

PURPOSE:To reduce video noise by detecting the lighting of 50Hz fluorescent light from a video signal and selecting a shutter speed automatically. CONSTITUTION:A component of video noise under fluorescent light lighting is a step difference of a video signal level of 3-field period and the storage time of a photoelectric conversion element 102 is controlled variably by the electronic method based on the result of detection of the step difference of the video signal level for each field with a step difference detection means 104 detecting the step difference of the video signal level for each 3-field. Thus, the video noise level under fluorescent light lighting of 50Hz power supply is reduced automatically. Thus, the video noise level at the pickup under the fluorescent light lighting of 50Hz power supply is reduced automatically to obtain an excellent picture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video camera device equipped with a photoelectric conversion element that can variably control the storage time.

BACKGROUND OF THE INVENTION In recent years, with the spread of video tape recorders, the development of video cameras has become more active, and video cameras are required to be smaller and lighter, have lower weight, have higher fat content, be multifunctional, and have higher operability. usually,
NTSC video cameras use photoelectric conversion elements that can control the storage time, but when used under fluorescent lighting with a 60Hz power source and a photoelectric conversion element storage time of 1/6° second, the image quality is remarkable. Noise occurs.

In order to solve the above problem, it is necessary to manually set the accumulation time of the photoelectric conversion element to 1/100 seconds, or, even for automatic setting, to set a dedicated device for sensing the fluorescent lighting conditions of a 60Hz power supply. A light receiving sensor is installed and the accumulation time of the photoelectric conversion element is set to 1710 ms based on the data of the light receiving sensor.
It was set to 0 seconds.

Problems to be Solved by the Invention However, in the conventional technology, the video camera user needs to set the accumulation time (shutter speed) of the photoelectric conversion element according to the lighting conditions. Also, it is necessary to install a dedicated light receiving sensor, and there are major issues such as high operability, small size and light weight, low price, and design constraints.

The present invention has focused on the above-mentioned problems, and has achieved high operability, small size and light weight,
The present invention provides a video camera device that solves both the problems of low cost and design constraints.

Precautionary Means for Solving the Problems As a precautionary measure for solving the above problems, the video camera device of the present invention includes step detection means for detecting steps in the video signal level every three fields of the video signal from the photoelectric conversion element; The present invention is characterized in that it further includes a control means for variably controlling the storage time of the photoelectric conversion element based on the detection result of the step in the video signal level every three fields by the step detection means.

According to the video camera device of the present invention, the component of video noise under fluorescent lamp illumination with a %5oHz power supply becomes a step in the video signal level of 3 field cycles, and a step in the video signal level for every 3 fields A/do. By electronically controlling the storage time of the photoelectric conversion element based on the detection result of the step difference in the video signal level for each field using the step detection means that detects the step difference in the video signal level, the video noise level under fluorescent lamp illumination with a 60 Hz power supply can be reduced. Can be automatically reduced. Therefore, it is possible to realize a video camera device that can automatically reduce the video noise level and obtain good images when shooting under fluorescent lamp illumination with a 50 Hz power supply. , Example Hereinafter, a video camera device according to an example of the present invention will be explained using the drawings.

FIG. 1 shows a block diagram of a video camera device according to an embodiment of the present invention. In FIG. 1, 101 is an optical lens;
2 is a solid-state image sensor, 103 is a signal processing unit, 104 is a signal step detection circuit for every three fields, 105 is a drive circuit for the solid-state image sensor, 106 is an optical input, 107 is an optical signal imaged by an optical lens, 1o8 is the output of the solid-state image sensor, 1
09 is a video camera! Output, 110 is a video luminance signal, 11
1 is the output from the signal step detection unit every 3 fields, 11
2 is a driving pulse for the solid-state image sensor.

The operation of the video camera device having the above configuration will be described below with reference to FIGS. 1, 2, and 3. The optical signal 10 formed through the optical lens 101 is photoelectrically converted by the solid-state image sensor 102 and becomes a solid-state image sensor output signal 108 . Next, the solid-state image sensor output signal 108 is subjected to various signal processing by the signal processing section 103 and becomes a video signal. At this time, if the lighting conditions are sunlight or a fluorescent light with a 60 Hz power supply, no noise will occur in the video signal as shown at 201 in Figure 2, but at the normal shutter speed of 1/60 sec. Under the fluorescent lamp illumination of the power source, as shown in FIG. 2 203, the signal repeats every three fields, causing significant noise in the video signal.

Here, when the luminance signal 110 from the signal processing section 10.3 is input to the step detection section 104, the output 111 of the signal level step detection section for every three fields under sunlight and θOHz illumination is 202 in FIG. It is fixed at L level as shown in FIG. 2, and becomes H level as shown at 204 in FIG. 2 under fluorescent lamp illumination of an SO Hz power supply. In addition, 2 in Figure 2
06 indicates one field period.

Next, the output of the signal level step detection section 104 for every 3 feeds is inputted to the solid-state image sensor drive circuit 106, and when the input is at L level, the shutter speed is set to 1/60 second, and when the input is at L level, the shutter speed is set to 1/60 second, and
When switching from L level to H level, it is set to 1/100 seconds, and when switching from L level to H level, it slowly transitions from 1/60 seconds to 1/10 seconds, and when switching from H level to L level, it is set to 1/100 seconds. 1/10 seconds to 1/60 when changing
Set to transition continuously to seconds.

Here, the operation of continuously shifting the shutter speed will be explained using FIG. 4.

In FIG. 4, 401 and 402 indicate the element drive pulse timing by the constant charge discharging means of the FITCCD, 401 is the vertical COD drive pulse of the photoelectric conversion section, 1.403 is the signal charge readout panorama, and 404 is the unnecessary charge. This is a read pulse. 402 is the vertical C of the storage section
It is an OD drive pulse, which transfers unnecessary charge at high speed during the 405 period, and transfers the signal charge at high speed during the 406 period. Red shift is performed and signal charges are output during 407 periods. Here, the shutter speed is controlled at the timing of issuing the unnecessary charge readout pulse 404, and has a period of 408.

In other words, it is possible to continuously vary the period 408 depending on the timing of the unnecessary charge read pulse 404.

In FIG. 4, 410 and 411 indicate element drive pulse timings by the unnecessary charge substrate discharge means of IT-CCD, 410 is a vertical CCD drive pulse, and 411 is a substrate (
Sub ) drive pulse.

The signal charge within the photoelectric conversion element is discharged to Sub every time the Sub voltage is modulated, and is not stored.

This period is shown at 412. After the sub modulation, the signal charge within the photoelectric conversion element is in an accumulation state, and the period shown at 413 until the signal charge readout pulse timing shown at 414 becomes the shutter speed (photoelectric conversion element accumulation time). That is, by continuously varying the Sub modulation period 412, it is possible to continuously vary the shutter speed 413.

Next, the operation of the system will be explained using FIG.

First, as shown in FIG. 3, the illumination is continuous until t=to, and the output of the signal level step detection section for every three fields shown at 302 in FIG. 3 is fixed at L level. As shown in 301, the shutter speed is set to 1/60 second.

Next, the illumination becomes a 50Hz power fluorescent lamp at t=t0, and 3
Since the output of the signal level step detection section for each field becomes H level, the shutter speed gradually shifts to 1/IQQ second, and becomes 1/100 second when 1=11. At this time, the signal level difference every 3 fields of the video signal disappears, so the output of the signal level difference detection section every 3 fields becomes L, and the shutter speed gradually increases to 1/8 o.
However, at 1=12, the signal level step detection section detects a slight noise again and becomes H level, so the shutter speed reaches 1/100 + ΔT seconds (1==12). It shifts to 17100 seconds again, and 1==13, which is 1/100 seconds. 60 like this
Under Hz fluorescent lighting, reduce the shutter speed to 1/1oo.
By confining it to around 1/100 seconds of ~1/10o+ΔT seconds, noise under 50-output fluorescent lamp illumination is reduced. Furthermore, if the illumination condition is removed from under the SOHz fluorescent lamp when 1=14, the output of the signal level step detection section for every 3 fields is fixed at L level, as shown at 302 in FIG. The speed gradually shifts to 1/60 second and is fixed.

In this way, when imaging under 50Hz fluorescent lamp illumination, the s
It becomes possible to detect o Hz fluorescent lamp illumination from the video signal and control the shutter speed to reduce noise.

Effects of the Invention As described above, according to the present invention, excellent effects such as detecting 50 Hz fluorescent lamp illumination from a video signal and automatically switching the shutter speed to reduce video noise can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the video camera device of the present invention, FIG. 2 is a waveform diagram of input and output signals of the signal level step detection section for every three fields of the same device, and FIGS. 3A and B 4 is an explanatory diagram of the operating principle of the device, and FIG. 4 is a timing chart of element drive pulses for explaining the method of controlling the storage time of the optical IF conversion element of the present invention. 102... Solid-state image sensor, 103...
Signal processing section, 104... 3-field step difference detection section, 106... Imaging element drive circuit.

Claims (1)

[Claims] a photoelectric conversion element capable of controlling storage time; a step detection means for detecting a step in the video signal level every three fields of a video signal from the photoelectric conversion element; and a control means for variably controlling the accumulation time of the photoelectric conversion element based on the detection result of the step, and by variably controlling the accumulation time of the photoelectric conversion element, the video noise level under fluorescent lamp illumination of a 50 Hz power source can be reduced. A video camera device characterized in that it is configured to automatically reduce the amount.