JPS60143090A - Camera device - Google Patents

Abstract

PURPOSE:To execute precisely white balance adjustment by detecting chrominance temperature information of peripheral light obtaining a control signal and holding the control signal for the prescribed time. CONSTITUTION:The outputs of photodetectors 402-404 of red, green and blue are fed to differential amplifiers 409 and 410 respectively, and the control signal which corresponds to the chrominance temperature is obtained. On the other hand, the control signal which corresponds to the chrominance temperature of flash is obtained by a control signal generation circuit 411 for flash photographing. Either of two control signals is selected by a switching SW circuit 412 in accordance with the photographing condition. Then, the selected control signal is synchronized to a shutter 421 by a hold circuit 413, and it is held until the timing of the necessary signal processing. The output of the hold circuit 413 is fed to variable gain-type image amplifiers 424 and 425, and white balance adjustment is executed. Thus, the precise balance adjustment can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to white balance adjustment in electronic camera devices.

Conventional configuration and its problems A conventional example will be explained below with reference to the drawings.

First, FIG. 1 shows the principle configuration of white balance adjustment.

In the figure, 101 is an image sensor, 102 is a separation circuit that separates the output of the image sensor into RSY and B signals, 103,
104 is a video amplifier having a voltage-controlled variable gain section; 1o5 is a differential amplifier for obtaining [R-YJ times the signal; 1
06 is a differential amplifier for obtaining l'-B-YJ times signal, 1
07 is an encoder.

In white balance adjustment, a white or achromatic subject is imaged through an imaging lens, this image is converted into an electrical signal by the imaging device 101, this signal is further converted into R, Y, and B signals by a separation circuit 102, and the image is amplifier 1
By controlling the gains of 03 and 104, the outputs of the differential amplifiers 105 and 106, "R-YJ,"
This makes the color difference signal zero.

Next, FIG. 2 shows a block diagram of a conventional camera device. In the figure, 201 is a photometric photodetector;
2.203.204 is a photodetector that detects each red, green, and blue light component; 205 is an amplifier for photometric photodetector output; 20
6 is an exposure control circuit, 207, 208, and 209 are amplifiers for the photodetector output of each color component, 210 and 211 are differential amplifiers, 212 is a lens, 213 is an aperture shutter, 214 is a shutter, 215 is a shutter control circuit, 216 1 is an aperture control circuit, 217 is a flash device, 218 is a flash control circuit, 101 to 1
07 is 101-1 of the white balance principle configuration diagram in Figure 1
Corresponds to 07.

This will be explained according to FIG. Conventional white balance adjustment uses detectors 202, 203, and 204 that detect red, green, and blue light components independent of the image sensor 101 to obtain light component signals of each color from a subject that corresponds to white, and then outputs light component signals of each color to an amplifier 207.2.
After amplification with 08.209, differential amplifier 210.211
``red-green'' and ``blue-green'' optical component signals are obtained. Using the obtained optical component signal as a control signal, the gain of the variable gain video amplifiers 103 and 104 is changed to control the level of the video signal lj, "B" which is the output signal of the separation circuit 102, and the differential amplifier 105 White balance adjustment is performed by adjusting the color difference signals "R-YJ, [B-YJ" which are the outputs of .106.

Also, in the case of electronic cameras, exposure control is necessary, so
For this purpose, a photometric photodetector 201 is provided, and after this output signal is amplified by an amplifier 205, an exposure control circuit 206 operates an aperture 9 control circuit 216 and a shutter control circuit 216 to control the aperture 213 and shutter 214. Depending on the state, the flash control circuit 218 is activated by the exposure control circuit 206 to control the flash circuit 217 to perform appropriate exposure control.

However, this conventional method includes the following problems.

First, FIG. 3 shows a timing diagram of an electronic camera. In the figure, (a) shows the control signal for color temperature correction obtained by the photodetector, (b) shows the shutter opening/closing state or the timing of accumulating a still image on the image sensor, and (C) shows the timing when the still image signal is read out. This is the timing to perform signal processing for color temperature correction.

The problems will be explained according to FIG. In the case of an electronic camera, as shown in FIGS. 3(B) and 3(C), there is a difference between the timing of storing still images in the image sensor and the timing of signal processing. Therefore, as shown by (-) in FIG. 3, there is a problem in that the control signal when storing a still image in the image sensor and the control signal when processing the signal after reading out change. This is especially true when the flash duration is instantaneous, such as during flash photography, and the aforementioned control signals change significantly, resulting in major problems in the reliability of white balance adjustment and in operability and mobility as shooting conditions change. There is.

OBJECT OF THE INVENTION The present invention is intended to eliminate such conventional problems, and to improve the reliability of white balance adjustment during normal shooting and flash photography regardless of the shooting conditions in an electronic camera, and to improve the accuracy of white balance adjustment regardless of the shooting conditions. An object of the present invention is to provide a camera device that can improve operability and mobility.

Structure of the Invention A camera device according to the present invention includes a color image sensor, a means for obtaining color temperature information of illumination light at the moment when a still image of a subject is stored in the color image sensor, and a means for obtaining color temperature information of illumination light at the moment when a still image of a subject is stored in the color image sensor, The device is equipped with means for reading and holding the information until the time of signal processing, and means for controlling the white balance of the color image sensor output based on the color temperature information, and ensuring reliability and operability of white balance control. , with improved maneuverability.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Fourth
The figure is a block diagram showing an embodiment of the camera device according to the present invention. In the figure, 401 is a photometric photodetector, and 402, 403, and 404 are photodetectors that detect red, green, and red light components. 405 is an amplifier for the photometric photodetector signal, 406, 407, and 408 are amplifiers for the photodetector signal of each color component, 409, 410 is a differential amplifier, and 411 is a control signal generation circuit corresponding to the color temperature of flash light. , 412 is a SW circuit for switching between normal photography and flash photography, 413 is a HOLD circuit for the output of the switching SW circuit, 414 is an exposure control circuit, 415 is a flash device, 416 is a flash control circuit, 417 is a shutter control circuit, 418 419 is an aperture control circuit, 419 is a lens, 420 is an aperture, 421 is a shutter, 422 is an image sensor, 423 is a separation circuit that separates the image sensor output into R-Y-E light, 424.425 is a voltage-controlled variable A video amplifier having a gain section, 426 a differential amplifier for obtaining the R-Y signal, 427 a differential amplifier for obtaining the B-Y signal, and 428 an encoder.

FIG. 5 is a timing chart of the electronic camera device according to the present invention. In the same figure, (a) is the output from the differential amplifier 409 or 410 obtained by the photodetector, (
b) is the output from the control signal generation circuit 411, (C) is the flash use designation signal from the exposure control circuit 414, (d) is the shutter opening/closing signal from the shutter control circuit 417, (
e) is the timing of the color temperature correction signal processing after reading out the still image signal performed by the variable gain amplifier 424 or 425, and (f) is the control signal used at the timing of (e).

The operation of the camera device configured as described above will be described below. When performing white balance adjustment at a certain color temperature as necessary, the red, green, and evening light detectors 402, 403, and 404 are used to capture a wide-angle subject (
The output power corresponding to each color component (corresponding to a white object) is obtained, and is amplified by amplifiers 406, 407, and 408 to make the output signal independent of the intensity of the incident light. The differential amplifiers 409 and 410 obtain control signals corresponding to the color temperature shown in FIG. 5(a).

For flash photography, a control signal generating circuit 411 generates a control signal (FIG. 5(1)) corresponding to the color temperature of the flash.

The two control signals shown in FIGS. 5(a) and 5(b) are input to the switching S'W circuit 412. Switching SW circuit 4
12 selects one of the 32 control signals (see FIG. 5(C)) depending on the photographing state. The selected control signal is held by the hold circuit 413 in synchronization with the shutter 421 [FIG. 5(d)] until the timing of necessary signal processing [FIG. 5(d)]. and hold circuit 41
The video amplifiers 424 and 425 having variable gain sections are controlled by the outputs of the differential amplifiers 426 and 427 (see FIG.
-Y" and "B-Y" are set to zero to perform white balance adjustment.

Still a photometric photodetector 401 to perform proper exposure control.
After this output signal is amplified by an amplifier 405, an exposure control circuit 414 determines whether a flash is necessary or not depending on the shooting condition and generates a signal [Fig. 5(C)] to instruct the flash, and also controls the aperture. The circuit 418 is operated to tighten the cylinder 420.
The shutter control circuit 417 is operated to control the shutter 421 and the HOLD circuit 413 using a shutter opening/closing signal [FIG. 5(d)].

Therefore, by detecting the color temperature information of the ambient light using a photodetector to obtain a control signal, and by providing a control signal generation circuit corresponding to the color temperature of the flash light for flash photography, it is possible to By providing a HOLD circuit, control can be held until required, allowing more accurate automatic white balance adjustment.

In the embodiment, the HOLD circuit 413 is opened and closed in synchronization with the shutter 421, but it may be synchronized with other appropriate signals.

Further, the switching 5W411 is automatically switched by the output signal from the exposure control circuit, but the same effect can be obtained even if it is switched manually.

Effects of the Invention As described above, according to the present invention, color temperature information of illumination light at the moment when a still image is stored in an image sensor can be retained until the time when the still image signal is read out and signal processed. Since white balance adjustment can be performed regardless of the imaging situation such as when photographing, excellent effects such as greatly increasing the reliability, operability, and mobility of the camera device can be obtained.

'4. Brief explanation of the drawings Figure 1 is a block diagram showing the principle of white balance adjustment, Figure 2 is a block diagram showing an example of a conventional camera device, and Figure 3 is a control signal for a conventional camera device. FIG. 4 is a block diagram showing an embodiment of the camera device according to the present invention, and FIG. 5 is a timing chart for explaining its operation.

401...Photometric photodetector, 402.403
.

404...Color component detection photodetector, 409, 4
10...Differential amplifier, 411...Control signal generation circuit, 412...Switching SW circuit,
413...Hold circuit, 417...
Shutter control circuit, 422...Image sensor, 4
23...Separation circuit, 424°425...
Variable gain video amplifier, 426, 427... differential amplifier, 428... encoder.

Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A color image sensor, a means for obtaining color temperature information of illumination light at the moment when a still image of a subject is stored in the color image sensor, and signal processing for reading out the color temperature information from the stored still image signal. means for retaining the information until the time to do so;
A camera device comprising means for controlling white balance of the output of the color image sensor based on the color temperature information. (2) The means for obtaining color temperature information of illumination light is comprised of means for detecting color temperature information of ambient light and means for generating a control signal corresponding to the color temperature of flash light, and the outputs of the two means 2. The camera device according to claim 1, further comprising a means for selecting the selected one according to the photographing situation.