JPH04317291A - Automatic color temperature correciton device - Google Patents

Abstract

PURPOSE:To resolve the problem of difficulty in discriminating between the change of a color signal due to the change of the color temperature of a light and the change of the color signal due to the change of an object in an automatic color temperature correction device used in a color TV camera and to provide the automatic color temperature correction device discriminating between a fluorescent light and the other light source regardless of the color of the object. CONSTITUTION:An output signal 106 of an image pickup element is inputted to a flicker detection part 105, the presence or absence of a flicker is discriminated from the presence or absence of a 20Hz component specific to the fluorescent light, and the signal is then outputted to a color temperature detection part 103 as a flicker presence/absence signal 112. A color temperature detection part 103 restricts gain control signals 113 and 114 with the flicker presence/absence signal 112. That is, when the flicker is detected, the light source is determined to be the fluorescent light and the control ranges of the gain control signals 113 and 114 are restricted to the control range of the fluorescent light. When the flicker is not detected, the light source is determined not to be the fluorescent light and the control ranges of the gain control signals 113 and 114 are restricted to the range of the light source other than the fluorescent light.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic color temperature correction device for a color TV.

0002

2. Description of the Related Art In recent years, automatic color temperature correction devices have been installed in color TV cameras, especially in the consumer field.

A conventional automatic color temperature correction device will be explained below. FIG. 2 is a block diagram of a conventional automatic color temperature correction device. In FIG. 2, 201 is a color image sensor;
02 is a color signal generation section, 203 is a color temperature detection section, 204 is a white balance control section, and 205 is a color signal formation section.

The operation of the automatic color temperature correction device configured as described above will be explained below. First, an optical signal is converted into an electrical signal by a color image sensor 201, and R, G, and B color signals are detected and output by a color signal generating section 202. This color signal is input to the color temperature detection unit 203, where the color temperature detection unit determines the color temperature based on the composition ratio of the R, G, and B signals, controls the white balance control unit 204, and corrects the color temperature. I do. The color signal subjected to white balance control is input to the color difference signal forming section 205, and a color difference signal is output.

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional configuration, the color temperature is determined based on the color signal obtained from the video signal (imaging signal). However, this method has the problem of confusing changes in color signals caused by changes in the subject.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an automatic color temperature correction device that can discriminate between fluorescent lamps and other light sources regardless of the color of an object.

[0007]

[Means for Solving the Problems] In order to solve this problem, the automatic color temperature correction device of the present invention has means for detecting the flicker component of the video signal and the lighting frequency of the fluorescent lamp, and the presence or absence of flicker determines the color. It has a configuration in which the temperature is input to the temperature detection section.

[0008]

[Operation] With this configuration, regardless of the color signal, whether or not the light source is a fluorescent lamp is determined by the presence or absence of a flicker component. In this case, the color temperature can be corrected within the range of light sources other than fluorescent lights, and even if the color of the subject changes, it can be avoided from being confused with a change in the light source.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an automatic color temperature correction device according to the present invention. In FIG. 1, 101 is a color image sensor, 102 is a color signal generation section, 103 is a color temperature detection section, 104 is a white balance control section, 105 is a flicker detection section, 106 is an output signal of the image sensor, 107 is an R signal,
108 is a B signal, 109 is a G signal, 110 is an RY color difference signal, 111 is a BY color difference signal, 112 is a signal indicating the presence or absence of flicker, 113 is a signal for controlling the B gain,
114 is a signal that controls the gain of R;

The operation of the automatic color temperature correction device configured as described above will be explained with reference to FIG. first,
The optical signal is converted into an electric signal 106 by the color image sensor 101 and inputted to the color signal generation section 102, which generates an R signal 107, a G signal 109, and a B signal 08.
is output as This color signal 107, 108, 109
is input to the color temperature detection section 103, and the color temperature detection section 10
3, the signal 1 determines the color temperature based on the composition ratio of the R signal 107, the G signal 109, and the B signal 108 and controls the R gain.
14. Output the signal 113 for controlling the B gain to the white balance control section 104. The white balance control section 104 performs gain control according to gain control signals 113 and 114, and outputs an RY color difference signal 110 and a BY color difference signal 111 whose white balance has been corrected. On the other hand, the output signal 106 of the image sensor is input to a flicker detection section 105, and the presence or absence of flicker is determined based on the presence or absence of a 20 Hz component specific to fluorescent lamps, and is output as a flicker presence/absence signal 112 to the color temperature detection section 103. The color temperature detection unit 103 generates gain control signals 113 and 11 based on the flicker presence/absence signal 112.
Add restrictions to 4. That is, if flicker is detected, the light source is identified as a fluorescent lamp and the gain control signals 113, 114 are
control range to the control range of fluorescent lamps. If no flicker is detected, it is determined that the lamp is not a fluorescent lamp, and the control range of the gain control signals 113 and 114 is controlled to the range of light sources other than fluorescent lamps.

As described above, according to this embodiment, it is specified whether the light source is a fluorescent lamp or not, regardless of the color signal. If this is not the case, the color temperature can be corrected within the range of light sources other than fluorescent lights, and even if the color of the subject changes, it can be avoided from being confused with a change in the light source.

[0013]

As described above, the present invention has a means for detecting the flicker component of the video signal and the lighting frequency of the fluorescent lamp, and has a configuration in which the presence or absence of flicker is input to the color temperature detection section. It is possible to realize an excellent automatic color temperature correction device that can avoid confusion with a change in the light source even if the color of the subject changes.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic color temperature correction device of the present invention.

Claims (1)

[Claims] Claim 1: A color imaging device, a color signal generation section,
An automatic color temperature correction device equipped with a color temperature detection section, a white balance control section, and a flicker detection section.