JPS5836091A - Color television camera device - Google Patents

Abstract

PURPOSE:To eliminate the influence of variance of a converter by sampling and holding each primary color video signal from image pickup elements of a color TV camera device and then switching signals by a phase difference which is an integral multiple of a clock, and thus obtaining conversion output of respective primary colors through the A/D converter. CONSTITUTION:Video signals obtained by image pickup elements 3a-3c for three primary colors through a lens system 1 and an optical system 2 are inputted to sample holding circuits 9a-9c through a preamplifier and signal processing circuits 4a-4c. A timing generator 11 generates three switching signals which are out of phase with a sampling signal from a clock signal, and sample holding operation is controlled by the sampling signal; and outputs are switched successively through a switch circuit 10 and converted by an A/D converter 5 into digital signals which correspond to the respective colors, and they are passed through gate circuits 11a-11c successively by the delayed switching signal, and then inputted to a signal synthesizer 7 through succeeding digital signal processing parts 6a-6c, thereby outputting a digital decoded color TV signal 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a color television camera device including:
The present invention relates to a digital color television camera device that is not affected by variations in analog-to-digital converters (hereinafter referred to as A/D converters).

In color television camera devices currently in use, an electric circuit processes the primary color video signals obtained from each image sensor, synthesizes a composite color television signal, and sends it to a video switch. Since signal processing was performed, the characteristics etc. were not sufficient.

In recent years, attempts have been made to digitally convert video signals and perform electrical processing digitally. This system diagram is shown in Figure 1. In FIG. 1, 1 is a lens system, 2 is an optical system, and generally a prism optical system is used. 3a to 3b are image pickup devices, in this case for three colors, red, green, and blue. That is, the image sensor 3a is for red, the image sensor 3b is for green, and the image sensor 3C is for blue.

These image sensors 3a to 3o include preamplifiers and signal processing circuits 4a to 4a, and A/D converters 5a to 4a, respectively.
5c, and are applied to the color signal synthesizer 7 via digital signal processing circuits 6a to 6cf. The color signal synthesizer 7 outputs a composite color television signal.

In this way, each primary color video signal is sent to the A/D converter 5.
The A/D converters 5a to 5c convert the signals into digital signals and perform digital processing, but three A/D converters 5a to 5c are required for each primary color video signal, that is, when handling the three primary color signals of red, green, and evening. .

However, the A/D converters 51 to 5c have a conversion error,
This error appears as non-linear distortion, and does not give a 1U linearity error between each primary color video signal, which impairs color reproducibility and adversely affects image quality.

Further, the A/D converters 5a to 5c themselves have temperature drift, and when a plurality of them are used, the triad difference affects the temperature stability of the entire system. Further A/
The D converters 5a to 5c are expensive), and using three of them has the disadvantage that the cost of the entire system increases.

This invention was made to eliminate the above-mentioned drawbacks of the conventional art, and it samples and bolds each primary color video signal obtained from an image sensor, switches the signals with a phase difference that is an integral multiple of the clock, and sequentially converts one A/ 'By supplying the digital signal to a D converter and distributing the digital output for each primary color digital signal, it is possible to reduce the influence of variations in the A/D converter at low cost, and to create a color television with good temperature stability. , its entire purpose is to provide a camera device for

Embodiments of the color television camera device of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of one embodiment.
Parts that are the same as those in the figures are given the same reference numerals and are only described briefly.
We will focus on the parts that differ from those in Figure 1.

In Figure 2, 1 is a lens system, 2 is a color separation optical system (f
The case of a rhythm optical system is shown. ), 3a to 3c are image pickup elements, 4a to 4c are Noriamp and signal processing circuits,
These parts are the same as in FIG.

However, the following points are significantly different from those in FIG. 1, and these Noriamp and signal processing circuits 48 to 48
The outputs of 4C are sample-and-hold circuits 9a to 9c, respectively.
is sent to the switch circuit 10 via the A/D converter 5
The signal is converted into a digital signal and introduced into r-) circuits 11a to Ilo. A sample signal and a switching signal from the timing generator 1 are sent to the sample and hold circuits 9a to 9c1, the switch circuit 10, and the dirt circuits 11h to 11e.

As shown in FIG. 3, this timing/guzo generator 11 generates a clock signal of 12 x f8c (f8o is the frequency of the subcarrier) from a black/flip generation circuit 110, and divides this clock signal by three in a frequency dividing circuit 111. Then, a clock signal is introduced into the pulse shaping circuit 112, and three switching signals (Aφ, Bφ, Cφ).

The switch circuit 10 is a part that is controlled by the timing of a clock signal and separates each primary color signal. The output of this switch circuit 10 is outputted to the dart circuits 11a to llc via the A/D converter 5f, and further to the dart circuits 11a to llc.
The output of lla is sent to digital signal processing circuits 6IL to 6ci.
1 is outputted to a signal synthesizer 7 via the signal synthesizer 7, and a dinotal composite color television signal 8 is output from the signal synthesizer 7.

Next, the operation of the color television camera apparatus of the present invention constructed as described above will be described with reference to the waveform diagrams shown in FIGS. 4(&) to 4(11).

When converting an analog video signal to digital, the number of bits is 8 or more and the sampling frequency is 478C = 1
There is no problem if you sample at 4 MHz or higher.

6- As mentioned above, the clock signal (Q) in the timing generator 1 is generated at 12×ffc as shown in FIG. 4(a), and the sample signal (S) shown in FIG. , ) is the sample hold circuit 9 a r 9
The switching signals (Aφ, Bφ, Cφ), which are supplied to the terminals b + 9c and have different phase differences, are shown in FIGS. 4(c) and 4(d).
It is generated as shown in (e). This switching signal (Aφ, Bφ.

Cφ) is supplied to the switch circuit 1o, and the switching signal (Aφ
), the sample and hold circuit u 9 a (7) output is derived, and the switching signals (Bφ) (Cφ) are used to derive the outputs of the υ sample hole 2 circuits 9b and 9c, respectively, and each primary color video signal is sent to the switch circuit 10. are sequentially switched and supplied to the l converter 5 as a series of signals. Switching signal (Aφ, B
φ, Cφ) divides the period of the sample signal (SP) into three as shown in the figure, and is supplied to the switch circuit 1θ and also to the delay circuit 12 as shown in FIG. 4(f) (g) f
As shown in h), it is delayed by the conversion time td of the converter 5. The r4 notalized video signal from the converter 5 is f
-) circuits 118-llc, and a delayed switching signal (Aφ') is supplied to these dart circuits 11&-llc.

Bφ/, Cφ') are respectively supplied, and digital signals are separated corresponding to each primary color video signal, processed by digital signal processing circuits 6a to 6c, and then sent to a color signal synthesizer 7.
The digitized composite signal is then output.

In the embodiment shown in FIG. 2, the clock is 4f, oX 3
= 12 We explained in fso, but in addition to this, there are 4
/ s c X 6-24 f6 (s 6fB C
Of course, it is possible to use s or any other frequency. In Figure 2, by using a common signal as the sample signal, even when each primary color signal is in the same phase, the sample and hold is performed at exactly the same phase, so there is no phase shift between the primary color signals. It has the advantage of

As described above, according to the color television camera device of the present invention, when digitizing each primary color video signal obtained from an image sensor, each primary color video signal is sampled and held at the same timing, and the clock is The signals are switched with a phase difference that is an integer multiple and sequentially supplied to one A/D converter, and the digital output is distributed for each primary color digital signal, making it possible to use an inexpensive A/D converter. This has the advantage that it is possible to essentially eliminate differences in variations in individual nonlinear distortions and differences in temperature drift, and there is no phase shift between the primary color video signals.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing the digital system of each primary color video signal of a conventional color television and camera device, and FIG. 2 is a circuit configuration diagram showing an embodiment of the color television and camera device of the present invention. , Fig. 3 is a circuit configuration diagram showing the timing generator of Fig. 2, Fig. 4(,) to Fig. 4(h)
1 and 2 are waveform diagrams for explaining the operation of the color television screen and camera device of the present invention, respectively. 1... Lens system, 2... Optical system, 3-3c...
Image sensor, 41L-4c...Preamplifier and signal processing circuit, 5...A/D converter, 6a-6c...Digital signal processing circuit, 7...Color signal synthesizer, 9a-
9c... Sample hold circuit, 1o... Switch circuit, 11... Timing generator. Applicant's agent Patent attorney Takehiko Suzue 10-

Claims (1)

[Claims] A sample hold circuit holds each primary color video signal obtained from the image sensor with a sample signal of a predetermined frequency at the same timing, and a switching signal that has mutually different phases within one period of the sample signal with a phase difference of an integral multiple. A switch circuit that sequentially switches each of the primary color video signals held in the sample hold circuit using switching signals having mutually different phases within one period of the sample signal; A single analog-to-digital converter converts into primary color digital signals, and the output of this analog-to-digital converter is divided into the respective primary color digital signals in synchronization with the above switching (i), and then the digitized composite color television signal is generated. A color television camera device consisting of an output means.