JPS61100623A - Automatic color temperature tracking apparatus - Google Patents

Abstract

PURPOSE:To enable automatic color temp. tracking reduced in an error, by obtaining the information of the change in color temp. by directly detecting the signal from an image pick-up device to obtain white balance. CONSTITUTION:The signal from an image pick-up device 11 is separated into red, green and blue signals by a color separation circuit. These signals are respectively applied to a high luminance part detection circuit 30 and high luminance signal removing circuits 16, 17, 18 to remove high luminance signals thereof and detected by the next peak detection circuits 19, 20, 21. The detected signals pass through differential amplifiers 22, 23, time constant circuits 28, 29, a matrix circuit 31 and an encoder circuit 32 to obtain an image signal. As mentioned above, because the signal from the image pick-up device is directly used, a color decomposition characteristic is out of the question and white balance reduced in an error can be taken.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to automatic color temperature tracking using an imaging device in order to always obtain a video signal with a good white balance without manual adjustment in video cameras, surveillance cameras, etc. Regarding equipment.

Structure of a conventional example and its problems FIG. 1 shows a conventional automatic color temperature tracking device. The configuration of this conventional example will be explained below with reference to FIG. 1. In FIG. 1, 1 is a red sensor, 2 is a blue sensor, and 3 is a differential amplifier. 4 is an inversion buffer, and 5 is an imaging device. 6 is a control circuit for controlling the gain of the green signal, 7 is a control circuit for the red signal, and 8 is a control circuit for the betrayal bone. In this case, the signal from the differential amplifier 3 is sent to the control circuit 7 and the inverting buffer 4
The signals are respectively supplied to the control circuit 8. 9
is the green, red, and back signal ma) IJ Nox circuit, and 9.
10 is a video signal encoder circuit.

Next, the operation of the above conventional example will be explained. In FIG. 1, light from an object is received by sensors 1 and 2, and a differential amplifier 3 obtains a difference signal. Here, among the signals from the imaging device 5, the gains of the red and blue signals are controlled by the signals from the differential amplifier 3 and the inverting buffer 4 by the control circuits 7 and 8, and the gain-controlled signals are By entering the Marelix circuit 9, a white balanced video signal is output from the encoder circuit 10.

However, in the above conventional example, the imaging device 5
Since the color separation characteristics are different between the sensor 1 and the sensor 2, an error occurs in tracking the color temperature. Furthermore, since the sensors 1 and 2 are located far away from the imaging device 5, the sensors 1 and 2 receive information received from the subject and some specific information, which also causes errors in color temperature tracking. There were drawbacks such as. Furthermore, the window of the sensor 1.2 must be provided in a different position from the imaging device 5.

Purpose of the Invention The present invention eliminates the drawbacks of the above-mentioned conventional example, and aims to obtain a signal for white balance directly from the signal of an imaging device, and thereby perform white balance. It is.

Structure of the Invention In order to achieve the above object, the present invention directly detects the signal from the imaging device to obtain information on color temperature change and obtain white balance, and detects the error by using the signal from the imaging device itself. This enables automatic color temperature tracking with minimal effort.

DESCRIPTION OF EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to the drawings. In Figure 2, %11 is the imaging device, %12
is a color separation circuit, and 13, 14, and 15 are gain control circuits for red, green, and blue signals, respectively. 16,1
7.18 is a high brightness signal removal circuit, 19, 20.21 is a peak detection circuit, 22゜23 is a differential amplifier, 24.25 is a sample hold circuit, and 26.27 is the gain of the red signal and blue signal, respectively. Control range limiting circuit, 2's and 29 are time constant circuits.

30 is a high brightness portion detection circuit, 31 is a matrix circuit.
232 is an encoder circuit.

Next, the operation of the above embodiment will be explained. In FIG. 2, a signal from an imaging device 11 is separated into red, green, and blue signals by a color separation circuit 12. In FIG. The high-luminance signal is removed from this signal by the high-luminance portion detection circuit 30 and the high-luminance signal removal circuits 16, 17.18, respectively, and then detected by the next peak detection circuits 19, 20, and 21. The detected signal becomes a difference signal between red and green and back and green by differential amplifiers 22 and 23, and is sent to the sample hold circuit 2.
After being converted into D and C signals by 4°25, the variable range is limited by gain control range limiting circuits 26 and 27, and after passing through time constant circuits 28 and 29, red signal and green signal gain control circuits 13 ', 15. The gain-controlled signal from the Huntroll circuit 13°14.15 enters the matrix circuit 31,
A video signal is obtained through an encoder circuit 32.

In this case, the high-brightness signal removal circuits 16 to 18 can remove in advance high-brightness signals that do not require white balance processing in the video signal. Also, time constant circuit 28.29
The time constant of color temperature tracking can be adjusted to human visual characteristics.

The gain control range limiting circuits 28 and 29 can be set so that color temperature tracking is not performed for extreme color temperatures that do not need to be tracked.

Effects of the Invention The present invention has the above-described configuration, and provides the following effects.

(a) Since signals from the imaging device are directly used, color separation characteristics are not a problem and white balance can be achieved with less error.

(1)) Since the signal from the imaging device is used directly, there is no difference in information from the subject unlike when a sensor is held separately, and white balance can be achieved with less error.

(C) The means for removing high-luminance signals can remove in advance high-luminance signals that are unnecessary for white balance processing.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional automatic color temperature tracking device, Figure 2 is a block diagram of a conventional automatic color temperature tracking device.
The figure is a block diagram of an automatic color temperature tracking device in one embodiment of the present invention. 11... Imaging device, 12... Color separation circuit, 13
. . . Red signal gain control circuit, 14 . . Green signal gain control circuit t, i s Medium back signal gain control circuit, 16, 17. 18 . . . High brightness removal circuit, 19, 20 .21...Peak detection circuit, 22
．． 23... Differential amplifier, 214.25... Sample hold circuit, 26.27... Gain control range limiting circuit,
28.29...Time constant circuit, 30...High brightness portion detection circuit, 31...Matrix circuit, 32...Encoder circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (2)

[Claims] (1) An automatic color temperature tracking device that directly detects a signal from an imaging device, samples and holds it to obtain information on color temperature changes, and performs automatic white balance of the device. (2) The automatic color temperature tracking device according to claim 1, which uses means for removing a high-luminance component and means for detecting the same as a means for detecting a signal from an imaging device.