JPS58151793A - Color tv camera device with automatic white balance - Google Patents

Abstract

PURPOSE:To use the camera with no adjustment under various light sources, by providing a function detecting the spectrum characteristics of light sources for the camera and performing the automatic correction of white balance. CONSTITUTION:A light inputted to a light source spectrum characteristic detection section is converted into an electric signal at photoelectric conversion elements RO, GO, BO having a peak of the sensitivity in red, green and blue color, and amplified at preamplifiers 2a-2c. Coefficients KR=SR/SG and KB=SB/SG are obtained respectively at comparators 2d, 2e, where SR, SG, SB are amplified signals. In a color camera 3, electric signals corresponding to red, green and blue colors are inputted to preamplifiers AR, AG, AB from image pickup tubes RT, GT, BT and amplified, and outputted as signals VR, VG, VB. The signals VR, VB, VG are gain-controlled based on the coefficients KR, KB at correction amplifiers 3a, 3b on the basis of the signal VG, based on the coefficients KR, KB to be suitable video signals and applied to a matrix circuit 31 together with the signal VG.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an Ocolor TV camera device that is capable of automatically correcting color tone changes in reproduced images due to differences in light source color temperature.

[Technical Background of Invention 0] In a color camera, the color tone of a reproduced image changes depending on the color temperature of the light source. Therefore, it is necessary to adjust the white balance every time the light source changes. The conventional white balance adjustment method is to adjust the reference object under a certain light source so that it appears as a white tip, and then project the subject.

[Problems with background technology]

However, particularly in ITV systems, the environment where cameras are installed is often poor, and the above-mentioned method is often difficult.

Under a light source whose color temperature changes over time, such as sunlight, it is necessary to adjust the white balance in response to the change.

[Purpose of the invention]

In order to solve these drawbacks, the present invention adds a function to the camera to detect the spectral characteristics of the light source, automatically corrects the white balance, and allows the camera to be used under a variety of light sources without the need for adjustments by the operator. The aim is to provide a color camera.

[Summary of the invention]

Therefore, in the present invention, a color camera device is constructed by a color camera having a light source spectral characteristic detection section and a level correction amplifier. In other words, the light source spectral characteristic detection unit receives light from the light source, separates it into the three colors of light, and calculates the relative values of other colors with respect to the color l among the three colors of light. , there is a photoelectric change corresponding to a color other than one of the original three colors! The objective was achieved by installing a level correction amplifier whose gain was controlled based on the relative value signal outputted from the light source spectral characteristic detection section.

[Embodiments of the invention]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

In the wholesaler 2Fi, the source spectral characteristic detection section s2 directs the light source spectral characteristic detection s2 to the light source laK, detects the spectral characteristic of the light source 11, and sends a correction signal to the color camera 3. Since the reflected light leg of the subject lb input to the color camera 3 is affected by the light source color at, if the video signal obtained by this reflected light leg is corrected with the correction signal described above, an appropriate video value can be obtained. It will be done. That is, the light source 1a emits the light source direct lights lel and leg to the subject 1b and the light source spectral characteristic detection unit 2, respectively. Light source direct light 1e1
-1e3, and reflected light 1e from subject 1b
2 is a spread affected by the direct light 1e1 from the light source.

Therefore, by the above-described correction, an appropriate video signal can be obtained.

The apparatus of the present invention will be explained in detail below with reference to FIG. I will clarify.

The light input to the light source spectroscopy 4I detection unit 2 is divided into 311 photoelectric conversion elements RO + Go + BO, which have sensitivity peaks in red, green, and blue visible light. The electrical signals are converted into electrical signals as signal components, and amplified by preamplifiers 2 a + 2 b + 2 c, respectively. These three preamplifiers are 2m+2b.

The three electrical signals outputted from 2c indicate the spectral characteristics of the light source 1g, and the signals VR and V within the color camera 3
Corresponds to G and V. The outputs of the preamplifier 2a and the preamplifier 2c are input to the - input terminal of the comparator 2d+2e, respectively, and the output of the preamplifier 2b is input to the - input terminal of the comparator 2d+2e.
It is input to the other input terminal of dt2g. And ratio 111
Outputs from 12d and 2e reach the color camera 3.

If the large signal amplified by preamplifiers 2m + 2b and 2c is 811 + 8g + 8B, comparison @2
In d, 8o and 8G are compared to find the coefficient, and similarly, in the comparator 2e, the coefficient is found. The coefficients kltkl are relative values of nine red and blue colors, respectively, with the green level of the light source 1a as a reference.

Specifically, the color camera 23 is an NTaC three-tube color camera, and optical signals corresponding to red, green, and blue are inputted from the image pickup tubes B+, GTE, and BT, and converted into electrical signals. This image pickup tube R,,GT.

The signals output from the BT are each preamplified by 8°AG.
, A, are input and increased, and the respective signals ■凰.

■. ,■, is output.

Preamplifier AB and preamplifier AIIK are each connected to level correction amplifiers 3a+3b afterward.

The output signal from the level correction amplifier aaKBs comparison 1i12d is input, and the output signal from the comparator 2e is input to the level correction amplifier 3b. Level correction amplifier 3a+3b includes comparator 2d t2e
Based on the output signal of the VR+VG+VB 01, which is affected by the temperature of the video, the gain is controlled by the level correction amplifiers 3a and 3b using the green ff, ) as a reference, and the appropriate video value is obtained. The signal is sent to the matrix circuit 31. In other words, it is considered as a level. Also, the signal corresponding to green is the ■ of that company. It is. Therefore, the signals corresponding to nine red and blue colors obtained from the subject 1b are corrected by being included in the light source IJI at a nine ratio (based on green) and become large signals.

In this example, no matter how the relative value of the spectral characteristics of the light source 1a changes, it is possible to always obtain a signal equivalent to when the subject is illuminated by a light source with a relative value of 1:1:1. . Therefore, an object that appears white under a certain amount of illumination will always appear white even if the light source changes. In other words, the white balance can be automatically adjusted. Even though it is called white, the color temperature that feels most white varies depending on the person and the color of Shuichi, so please use the above correction and 1it.
s, the adder, 11M and Qli signals are output to the adder via a low-pass filter 33 and a modulator. Adder Ade these Y, 1. Q signal is added,
It is output as a video signal.

In the above description, the embodiment has been explained using Fi and green as a reference, but the apparatus may be made using red or blue as a reference. just,
Green is the center of the W4 wavenumber of visible light from red to violet, and it is easier to construct a flexible device if green is used as a reference.

〔Effect of the invention〕

As explained above, the color camera device of the present invention, which is directed directly at the light source and has nine auto white balance adjustment functions, eliminates the need to image a white sheet of paper and adjust the white balance in advance, and the video signal Automatic correction is performed even under light sources.

Therefore, the operator does not have to make on-site adjustments when setting up the TV camera or adjust the white balance every time the light source changes, which is extremely convenient.

[Brief explanation of the drawing]

Figure 111 is a conceptual diagram of rounding to explain the present invention, and Figure jlK2 is a block diagram of an embodiment of the present invention. 1 light 61 lb...Subject LEL *
1s4...Direct light from the light source 1e,...Reflected light 2.
・°Light source spectral % detection s 3...Color camera 2a
e2b*2c...Preamplifier 2d, 2e...Comparator 3 a + 3 b...Reher correction amplifier agent Patent attorney Book E8 Fist Figure 1 Figure 2

Claims (1)

[Claims] Receives light from a light source and decomposes it into the 3fi colors of light.
A light source spectral ratio detection device for determining the relative value of one of the primary colors to another color, and a photoelectric conversion device that corresponds to a color other than one of the three primary colors of light are installed on the line. and a color camera having a level correction amplifier whose gain is controlled based on the nine relative value signals output by the light source spectral characteristic detection section.