JPS6126391A - White balance adjuster for color video camera - Google Patents

Abstract

PURPOSE:To reduce mulfunction of the white balance adjustment under plural light sources by changing the natural lighting direction of a color temperature detector in accordance with a zoom magnification. CONSTITUTION:When an optical lens system 1 is in the state of a telephoto lens, a color temperature natural lighting direction setter 8 sets the natural lighting direction of a color temperature detector 6 to the forward direction. In this state, the photographing is executed. When the optical lens system 1 is in the state of a wide angle lens, the color temperature natural lighting direction setter 8 sets the natural lighting direction of the color temperature detector 6 to the upward direction in response to a signal from a zoom magnification setter 7. Thus, whatever the zoom magnification is, the natural lighting direction of the color temperature detector can be set always in accordance with the zoom magnification.

Description

[Detailed Description of the Invention] [Technical Field of the Invention J] The present invention relates to a white balance adjustment device for a color video camera, and in particular, a white balance adjustment device for a color video camera, which is equipped with a color temperature detector whose light receiving direction is variable, and which adjusts the white balance according to the zoom magnification of an optical lens system. The present invention relates to a white balance adjustment device that improves the responsiveness of white balance adjustment to the color temperature of a subject by changing the lighting direction of a color temperature detector.

[Prior Art] FIG. 1 is a block diagram showing the configuration of a conventional white balance adjustment device. In FIG. 1, the white balance adjustment device is
An optical lens system 1 that conveys optical information of a subject, an m-image element 2 that separates the optical information conveyed by the optical lens system 1 into three primary colors of red, blue, and green and converts them into corresponding electrical signals, and an image sensor 2
A red signal preamplifier 3a and a green signal preamplifier 3 amplify the red, green, and blue video signals optically to electrically converted by the
b. A blue signal preamplifier 3C, a red signal variable gain amplifier 4a for white balance, and a blue signal variable gain amplifier 4b for white balance, which adjust the levels of the red signal and blue signal, respectively.
and a color temperature detector 6 that detects the color temperature of the subject and controls the amplification degree of each gain amplifier 4a, 4b using its output signal.
It consists of

The signals from the red signal variable gain amplifier 4a for white balance, the green signal preamplifier 3b, and the red signal variable amplifier 4b for white balance are subjected to various signal processing by subsequent processes and color encoder 5 to become video image signals.

The operation of the white balance adjustment device will be described below.

The color temperature detector 6 generates a color temperature signal corresponding to the color temperature of the light source light by detecting the ratio of the red component and the blue component contained in the light source light illuminating the subject. Optical lens system 1. A red signal and a green signal pass through the image sensor 2.

Optical-to-electrical conversion is performed into a green video signal. The red signal, green signal, and blue signal converted into electrical signals are each sent to a preamplifier 3a.
, 3b, 3c. Of these, the red signal and the blue signal are input to a red signal variable gain amplifier 4a for white balance and a blue signal variable gain amplifier 4b for white balance to adjust the signal level, respectively, in order to adjust the white balance of the video signal. Adjustment of this signal level is performed using the light 8! that illuminates the subject detected by the color temperature detector 6! Controlled to correspond to the ratio of red lights and green lights included in death.

Thereafter, it is converted into a video image signal by subsequent processing and the encoder 5. The conventional device is configured as described above and automatically adjusts the white balance.

In the conventional white balance adjustment device described above, there is no problem under a single light source, and the white balance adjustment is performed accurately corresponding to the color 2 degree of the subject. However, when shadows appear under multiple light sources, there may be a difference between the color temperature of the subject and the color temperature of the light source detected by the color temperature detector 6 (especially when using a video camera). (when there are light sources with different color temperatures in front and above the camera), the white balance cannot be adjusted correctly and a clear color image cannot be obtained.

[Summary of the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks and provide a white balance adjustment device that can correctly adjust white balance even under a plurality of light sources.

To summarize, the present invention is a white balance adjustment device that includes a color temperature detector whose lighting direction is variable and changes the lighting direction in accordance with the zoom magnification of an optical lens system.

The objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

[Embodiment of the Invention] The phenomenon in which the white balance is not adjusted correctly due to a difference between the color temperature detected by the color temperature detector 6 and the color temperature perceived by the optical lens system 1 under the plurality of light sources described above can be solved. ,
This often occurs when light sources with different color temperatures are placed in front and above the color video camera, respectively.

In addition, in such a case, when the optical lens system 1 is in the telephoto lens state, the white balance is adjusted according to the color temperature of the light source placed in front of the camera, and the optical lens system 1 is in the wide-angle lens state. It has been confirmed that a normal white balance can be obtained by adjusting the white balance according to the color temperature of the light source placed above the camera. This invention is based on this fact.

FIG. 2 is a block circuit diagram of a white balance adjustment device that is an embodiment of the present invention. In FIG. 2, unlike the conventional white balance adjustment device shown in FIG. 1, the light direction of the color temperature detector 6 is variable. Additionally, a new zoom magnification detector 7 for detecting the zoom magnification of the optical lens system 1,
A color temperature lighting direction 8 for setting the lighting direction of the color temperature detector 6 in response to the output signal of the zoom magnification detector 7 is provided. The operation of the white balance adjusting device according to one embodiment of the present invention will be described below.

First, consider the state in which the optical lens system 1 is a telephoto lens (when the zoom magnification is large). At this time, the zoom magnification detector 7 detects the zoom magnification of the optical lens system 1. The color temperature lighting direction setting device 8 sets the lighting direction of the color temperature detector 6 in the forward direction in response to a signal from the zoom magnification detector 7.

Shoot in this state.

Next, consider a state in which the Lens Lens System 1 is a wide-angle lens (when the zoom magnification is small). At this time, the color temperature lighting direction setting device 8 sets the lighting direction of the color temperature detector 6 upward in response to the signal from the zoom magnification detector 7.

That is, no matter what the zoom magnification, the lighting direction of the color temperature detector is always set in accordance with the zoom magnification.

Note that the means for changing the lighting angle of the color temperature detector in accordance with the zoom magnification may be either mechanical means such as gears or electrical means such as a motor (although the effect is the same). .

[Effect of the invention] As described above, in this invention, corresponding to the zoom magnification,
Since the color temperature detector is configured to change the lighting direction, malfunctions in white balance adjustment can be reduced even when there are light sources with different color temperatures in front and above the color video camera. A color image is obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional white balance adjustment device. FIG. 2 is a block diagram of a white balance adjusting device which is an embodiment of the present invention. In the figure, 1 is an optical lens system, 6 color density detectors, 7 is a zoom magnification detector, and 8 is a color temperature lighting direction setting device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Procedural amendment (voluntary) 21 Name of the invention White balance adjustment device for color video camera 3 Relationship to the person making the amendment Hitoshi Katayama, representative of the patent applicant Department 4, Agent 5, Claims column and Detailed Description of the Invention column 6 of the specification to be amended, Contents of the amendment (1) The Claims column of the specification will be corrected as shown in the attached sheet. (2) Change variable gain amplifier 4a J to [variable gain amplifier 4a J] on page 3, line 190 of the specification. (3) “Variable gain amplifier 4bJ” on page 3, line 1 of the specification
Correct to [variable gain amplifier 4b, J. (4) "Each gain amplifier J" in the second line of page 3 of the specification is corrected to "each variable gain amplifier." (5) Change “variable gain amplifier” in line 4 of page 3 of the specification to “
Corrected to "variable gain amplifier". (6) "Variable amplifier" in lines 5 and 6 of page 3 of the specification is corrected to "variable gain amplifier." (7) "Variable gain amplifier" on page 3, lines 19 and 20 of the specification is corrected to "variable gain amplifier." (8) From page 3, line 20 to page 4, line 1 of the specification, “
Correct variable gain amplifier 4bJ to [variable gain amplifier 4b,J. (9> Correct the color subdivision exhibited by the subject in line 13 of page 4 of the specification to; - the color temperature of the light source illuminating the subject.) (10) "Direction 8" in line 12 of page 6 of the specification. is corrected to "one-direction setting device 8".The above claims include: a color temperature detecting means for detecting color temperature with a variable lighting method; a zoom magnification detecting means for detecting the zoom magnification; a white balance for a color video camera, comprising a lighting direction setting means for setting a lighting direction of the color temperature detection means in response to a zoom magnification signal from the zoom magnification detection means;
N difference device. (2) As the zoom magnification increases, the lighting direction approaches a direction parallel to the optical axis of the optical lens system;
A white balance adjustment device for a color video camera according to claim 1. Procedural amendment (voluntary) 1. Display of the incident Patent application 1984-. 149015 No. 2
, Title of the invention: White balance adjustment device for color video camera 3, Representative Hitoshi Katayama of the person making the amendment, Part 5, Claims column 6 of the specification to be amended, Contents of the amendment, Claims on the attached sheet. Correct accordingly. - Above 2, Claim (1) A white balance adjustment device for a color video camera including an optical lens system with variable zoom magnification, comprising: a color temperature detection means for detecting color temperature with a variable lighting mullion; , for a color video camera, comprising: zoom magnification detection means for detecting the zoom magnification; and lighting direction setting means for setting the lighting direction of the color temperature detection means in response to a zoom magnification signal from the zoom magnification detection means. White balance adjustment device. (2) As the zoom magnification increases, the lighting direction approaches a direction parallel to the optical axis of the optical lens system;
A white balance adjustment device for a color video camera according to claim 1. -FA(I

Claims (2)

[Claims] (1) A white balance adjustment device for a color video camera including an optical lens system with a variable zoom magnification that shoots under a plurality of light sources having different color temperatures, the color temperature of which is variable in the lighting direction. a color temperature detection means for detecting; a zoom magnification detection means for detecting the zoom magnification; and a lighting direction setting means for setting a lighting direction of the color temperature detection means in response to a zoom magnification signal from the zoom magnification detection means. A white balance adjustment device for color video cameras, including: (2) The white balance adjustment device for a color video camera according to claim 1, wherein the lighting direction approaches a direction parallel to the optical axis of the optical lens system as the zoom magnification increases.