JPH05145837A - Video camera equipment - Google Patents

Abstract

PURPOSE:To set automatically dispersion in the sensitivity among plural image pickup elements and a pre-KNEE point. CONSTITUTION:The equipment is provided with gain adjustment amplifiers 8R, 8G, 8B arranged between outputs of image pickup elements 4R, 4G, 4B and outputs of calibration amplifiers 9R, 9G, 9B and KNEE circuits 14R, 14G, 14B connected to post-stages of the amplifiers, and video detection output data resulting from outputs of the amplifiers 8R, 8G, 8B, 9R, 9G, 9B converted digitally are fed to a microcomputer (CPU) and based on the CPU, the gain of the amplifiers 8R, 8G, 8B, 9R, 9G, 9B is adjusted automatically and the KNEE point of the KNEE circuits 14R, 14G, 14B is set automatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera device suitable for automatic gain adjustment of a two-plate (tube) type or a three-plate (tube) type video camera device.

[0002]

2. Description of the Related Art In a two-plate (tube) type or three-plate (tube) type color video camera device which is widely used in conventional broadcasting stations, for example, two solid-state image pickup devices such as CCDs (charge coupled devices) are used. A color video camera device is configured by using three pieces. For this reason, two or three CCDs are selected that have the same characteristics, but the input and output characteristics have variations in sensitivity.

A configuration for performing such sensitivity variation adjustment will be described with reference to FIGS. 3 and 4.

In FIG. 3, the outputs of the three-plate CCDs 4R, 4G and 4B for R (red), G (green) and B (blue) are not shown, but will be described later in CDS (correlated double sampling).
Gain adjusting amplifiers 8R ₁ , 8G ₁ and 8B through a circuit
Supplied to ₁ .

These gain adjustment amplifiers 8R ₁ , 8G ₁ and 8B ₁ are provided with manual variable resistors 30R, 3 for gain adjustment.
With 0G and 30B.

Gain adjusting amplifiers 8R ₁ , 8G ₁ and 8B
The output of ₁ is supplied to the adder circuits 11R, 11G and 11B. These summing circuits 11R, the 11G and 11B are made as the output for calibration from the calibration amplifier 9R _1, 9G ₁ and 9B ₁ is added, these calibration amplifiers 9R _1,
A calibration signal having a sawtooth waveform (hereinafter referred to as a CAL signal) is input from the calibration terminal 10 to the inputs of 9G ₁ and 9B ₁ .

The above-mentioned calibration amplifiers 9R ₁ , 9G ₁ and 9
Manual adjustable variable resistor 31 a calibration value level to B ₁
R, 31G and 31B are provided.

The outputs of the adder circuits 11R, 11G and 11B are supplied to the analog process circuit 29 of the camera. The process circuit 29 includes a clamp circuit, a white clip circuit, a knee circuit, a blanking insertion circuit, a gamma correction circuit, a black clip circuit, etc., as shown in FIG.
Then, only knee circuits 14R ₁ , 14G ₁ and 14B ₁ are shown.

The knee circuits 14R ₁ , 14G ₁ and 14
Variable resistors 32R, 32G and 32B as well as 33 which can manually adjust the knee point and the knee level are also provided in B _1.
R, 33G and 33B are provided, and the output of the process amplifier circuit is configured to output a television signal such as NTSC to the output terminal via the digital video signal processing circuit 17 and the like.

[0010]

In the above-mentioned conventional structure, by adjusting the variations of the CCDs 4R, 4G and 4B for R, G and B, the gain of R: G: B is 1: 1: 1.
In order to adjust the gain, the semi-fixed variable resistors 30R, 30G and 30B are manually turned to obtain the gain adjusting amplifiers 8R ₁ and 8G _1.
And 8B ₁ gains were changed so that the R, G, and B CCDs had the same sensitivity.

Similarly, a C-shaped sawtooth waveform is applied from the calibration terminal 10.
Calibration amplifier 9R ₁ to AL signal, 9G ₁ and 9B calibration amplifier 9R ₁ supplied to the _1, 9G ₁ and variable resistor 31R also semi-fixed to the case of adjusting the gain variation of 9B _1,
Calibration amplifier 9 by manually adjusting 31G and 31B
The gains of R ₁ , 9G ₁ and 9B ₁ are the same.

Further, also in the case of knee adjustment, white clipping is performed at four times the standard level as shown in FIG. 4B based on the L level sawtooth wave CAL signal shown in FIG. 4A input from the calibration terminal 10. Later, the video signal waveform 35 is 110-
The knee setting is performed so that it becomes about 130%. At this time, the knee point 34 is set to the knee point variable resistor 32.
R, 32G and 32B as well as the knee point level variable resistors 33R, 33G and 33B are manually adjusted to match the calibration voltage. However, since this knee point 34 is an inflection point, specify this portion. In addition to being very difficult, there is a problem that it takes a lot of time and means to manually adjust the variable resistors 32R, 32G, 32B as well as the 33R, 33G, 33B.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to be able to automatically compensate for variations in sensitivity among a plurality of image pickup devices such as CCDs, and to It is an object to provide a video camera device capable of automatically setting points.

[0014]

The video camera device of the present invention has image pickup elements 4R and 4R as shown in FIG.
Gain adjusting amplifiers 8R, 8G and 8B provided between the outputs of G and 4B and the calibration amplifiers 9R, 9G and 9B, and a knee processing circuit connected to the subsequent stage of the gain adjusting amplifiers 8R, 8G and 8B. 14R, 14G, 14B and knee processing circuit 1
A digital video signal processing circuit 17 that converts the outputs of 4R, 14G, and 14B into digital data to process a digital video signal, and a microcomputer that outputs a control signal based on imaging input data from the digital video signal processing circuit 17. 22 and the gain adjusting amplifier circuits 8R, 8G, 8B or the knee processing circuits 14R, 14G, 14B are automatically adjusted based on the control signal of the microcomputer 22.

[0015]

According to the video camera device of the present invention, it is possible to obtain a device in which sensitivity variations and / or knee points are automatically set among a plurality of image pickup devices, and readjustment is extremely easy.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-plate color video camera device using a CCD of the present invention will be described below in detail.

FIG. 1 shows an overall system diagram of this embodiment. 1 is a subject, 2 is an optical system such as a relay lens, 3 is a diaphragm, and a dichroic prism 6 for separating R, G and B is used.
CCD4 for R, G and B via R, 6G and 6B
R, 4G, and 4B are arranged to face the end faces of the dichroic prisms.

The focus lens or the like of the optical system 2 is slidable in the direction of the optical axis LX via the drive motor 5,
The iris of the drive motor 5 and the diaphragm 3 is based on a control signal obtained by converting digital control data from a microcomputer (hereinafter referred to as CPU) 22 into an analog signal by a digital-analog conversion circuit (hereinafter referred to as DAC) 27. It is designed to control automatically.

CCDs 4R, 4G and 4 for R, G and B
The output of B is supplied to the first to third CDSs 7R, 7G and 7B. The CDSs 7R, 7G, and 7B are correlated double sampling circuits provided to reduce the reset noise, and the KTC noise generated at the time of resetting the floating diffusion appears in the zero level period after the reset period of the CCD. The circuit configuration is such that this potential is clamped and the signal in the signal period that is continuously output after the zero level period is sampled and held.

The outputs of the CDSs 7R, 7G and 7B are supplied to gain adjusting amplifiers 8R, 8G and 8B. This gain adjusting amplifier is composed of a variable gain amplifier capable of purely electrically adjusting the gain. These gain adjusting amplifiers 8R,
Control data from the CPU 22 is DAC for 8G and 8B.
It is supplied to 25 and converted into an analog signal, and for example, 12 parallel outputs are supplied as a control signal.

The outputs of the gain adjusting amplifiers 8R, 8G and 8B are supplied to the adding circuits 11R, 11G and 11B.
The adder circuits 11R, 11G, and 11B are configured to add the calibration outputs from the calibration amplifiers 9R, 9G, and 9B. The inputs of the calibration amplifiers 9R, 9G, and 9B are rectangular from the calibration terminal 10. Waveform calibration signal (hereinafter C
An AL signal will be input).

The above-mentioned calibration amplifiers 9R, 9G and 9B are also constituted by variable gain amplifiers whose calibration value level can be adjusted purely electrically. These calibration amplifiers 9R, 9G and 9
B is also controlled by, for example, 12 parallel analog control signals which are analog signals by supplying the control data from the CPU 22 to the DAC 25.

The outputs of the adder circuits 11R, 11G and 11B are supplied to the gain amplifier switches 12R, 12G and 12B. This switch is, for example, 0 dB, 3 dB, 6 d
Calibration and gain adjustment amplifiers 9R, 9G and 9B for each B
And 8R, 8G and 8B gains are switched,
This switching signal supplies control data from the CPU 22 to the gain changeover switch 26, and the gain of the input signal is selected, for example, every 3 dB by three parallel analog signals from the gain changeover switch 26.

The outputs of the gain amplifier switches 12R, 12G and 12B are supplied to the white balance circuits 13R, 13G and 13B. These white balance circuits 1
3R, 13G and 13B set the control data of the CPU 22 to D
Constant R, G and B converted into analog signals by AC25
Based on the gain control signal, the gain for G between the three CCDs is matched, and the next knee (KNEE: white compression)
It is supplied to the circuits 14R, 14G and 14B. The knee circuits 14R, 14G, and 14B perform the same knee adjustment as described with reference to FIG.
A control signal obtained by analog-converting the control data from 22 into the DAC 25 is supplied.

After the knee circuits 14R, 14G and 14B knee points and the like are determined, the amplifiers 15R, 15G and 1
Digital video signal processing circuit 17 after being amplified by 5B or the like
Is supplied to. In the digital video signal processing circuit 17, R,
The G and B image pickup video signals are converted into digital data by analog-to-digital conversion circuits (hereinafter referred to as ADCs) 16R, 16G and 16B, and then supplied to the digital measuring system path 28 to obtain R, G and B image pickup video signals. Of the gain adjustment amplifiers 8R, 8G and 8B, the calibration amplifiers 9R, 9G and 9B, and the knee circuits 14R and 14 based on the detection output of the knee point voltage detected during the calibration.
A control signal is output so as to adjust the values of G and 14B to predetermined values, and the adjusted values are stored in the nonvolatile storage element (E ² PRO).
M) 24.

The digital video signal processing circuit 17 has a matrix circuit 18 and an encoder circuit 19, and R,
The G and B signals are converted into, for example, NTSC signals and the like, and the
It is configured to be output to the output terminal 21 via 20 as an analog signal.

The adjusting method in the above configuration will be described with reference to FIG.

First, in FIG. 1, the subject 1 is entirely white, for example, with a prescribed illuminance, and the white temperature is, for example, 3200 ° K. In order to take an image of such a subject 1 that is entirely white through the optical system 2, the Asiast switch 23 of the CPU 22 is manually turned on.
To

Next, the optical system 2 and the diaphragm 3 are adjusted via the DAC 27 based on the control data from the CPU 22, and the F value = f / D of the optical system 2 is set to a predetermined F value. Here, f is the focal length, and D is the diameter of the lens of the optical system 2.

Further, based on the control data from the CPU 22, the gain switching switch 26 is selected to have a gain of 0 dB, and the outputs of the gain switches 12R, 12G and 12B are switched to 0 dB.

The white balance circuits 13R, 13G and 13B are set to preset values, and the knee circuits 14R, 14G and 14B are set so as not to be applied to the pleni.

In this state, the CDS7R, 7G and 7B
Output signal from the camera, that is, gain adjustment amplifiers 8R and 8G
And 8B so that the gain of the image pickup input signal to be a predetermined value becomes R _LEV , G via the CPU 22 and the DAC 25.
Adjust _LEV and B _LEV .

CCD 4R, 4G and 4B are adjusted by such adjustment.
The variation in the sensitivity of is automatically adjusted.

Next, the iris of the diaphragm is closed and the calibration terminal 10
To supply the CAL ₁ signal. As the CAL ₁ signal in this case, a rectangular waveform of a predetermined level L is inserted instead of the sawtooth waveform as shown in FIG. 2A.

In this state, the CDS7R, 7G and 7B
Imaging output signal from the, or gain adjustment amplifier 8R, via the CPU22 and DAC25 as the gain of the image input signal has a predetermined value that is input to 8G and 8B R _CAL, G
Adjust _CAL and B _CAL .

With such an adjustment, the gain adjustment of the calibration amplifiers 9R, 9G and 9B is automatically completed.

Next, with the iris closed, a CAL ₁ signal having a rectangular waveform is supplied from the calibration terminal 10 to the calibration amplifiers 9R, 9G and 9B, and the gain changeover switch 26 is switched to 9d.
At the switching point of B, as shown in FIG. 2A, the output level L of the CAL ₁ signal of the gain amplifier switches 12R, 12G and 12B is set to L = 9 dB.

In this example, as shown in FIG. 2B, the knee point 34 is not observed as in the conventional case, but the maximum value 36 of the video signal waveform 35 is detected. That is, since the slope of the knee slope is always constant, the knee point 34 and each maximum value point correspond to 1: 1. According to such a detection method, since the portion to be detected is flat, automatic detection can be performed very easily.

That is, in the digital measuring system path 28, the maximum value 36
The knee circuit 14R, so that the value of becomes a predetermined value L ₁ ,
The voltages of 14G and 14B are detected, and the knee point 34 is automatically adjusted to converge to a desired value.

According to the present invention, it is possible to obtain a device in which variations in the sensitivity of a plurality of CCDs and gain adjustment of a calibration amplifier, or even a pleni point or the like can be completely automatically adjusted every time the power is turned on. Furthermore, the color temperature standard of the camera at the time of shipment is 32.
If the temperature was 00 ° K, the color temperature of the customer's operation is 300
If the temperature is 0 ° K or the like, readjustment is necessary, but such readjustment can be performed very easily.

In the above-mentioned embodiments, the three-plate type CCD is explained, but the three-tube type using an image pickup tube or the like, the two-tube type or the C type.
Obviously, it can be applied to a two-disc type video camera device of a CD.

[0042]

According to the video camera apparatus of the present invention, for example, sensitivity adjustment for compensating variations in sensitivity of R, G, B of the three-plate type, gain adjustment of a calibration amplifier, and Since the knee point setting can be completely automated, variations in color reproduction are suppressed, the quality of the video camera can be kept constant, and readjustment is easy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a video camera device of the present invention.

FIG. 2 is an explanatory waveform diagram of a calibration method of the video camera device of the present invention.

FIG. 3 is a configuration diagram of a main part of a conventional video camera device.

FIG. 4 is an explanatory waveform diagram of a conventional method for calibrating a video camera device.

[Explanation of symbols]

 4R, 4G, 4B CCD 8R, 8G, 8B Gain adjustment amplifier 9R, 9G, 9B Calibration amplifier 12R, 12G, 12B Gain amplifier switch 14R, 14G, 14B Knee circuit 22 CPU 23 Adjust switch

Claims (1)

[Claims] 1. A gain adjusting amplifier provided between an output of an image pickup device and an output of a calibration amplifier, a knee processing circuit connected to a subsequent stage of the gain adjusting amplifier, and an output of the knee processing circuit. A digital video signal processing circuit for converting a digital video signal into digital data to process a digital video signal, a microcomputer for outputting a control signal based on image pickup input data from the digital video signal processing circuit, and a control signal for the microcomputer A video camera device characterized in that the gain adjusting amplifier circuit or the knee processing circuit is automatically adjusted based on the above.