JPS60105390A - Camera device - Google Patents

Abstract

PURPOSE:To automatically control exposure and to adjust the white balance by obtaining the signal correcting the shift of the white balance corresponding to respective color temperatures and a signal corresponding to the incident light with the photodetector which is independent from a pickup element. CONSTITUTION:The light of the blue and red components from the subject is respectively detected with photodetectors 24 and 25 which are independent from a pickup element 35, and are amplified with logarithm amplifiers 26 and 27. A differential amplifier 29 inputs the output of logarithm amplifiers 26 and 27 and outputs the signal corresponding to a certain color temperature. A voltage converter 31 converts and synthesizes the signal to necessary color temperature- voltage characteristics. The gain of an image amplifier 37 having the variable gain area is controlled with the output signal of a voltage converter 31. An addition amplifier 28 addes the output of logarithm amplifiers 26 and 27 and outputs the signal corresponding to the intensity of the incident light. An exposure control circuit 30 operates a diaphragm control circuit 40 and a shutter control circuit 41 and controls suitably the exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a camera P device such as an electronic camera device.
In particular, it relates to white balance adjustment and exposure control.

Conventional configuration and its problems A conventional camera device will be explained using FIG. 1 and VT52. First, FIG. 1 shows the principle configuration of white balance adjustment. In the figure, 1 is a positive image element, 2 is a separation circuit that separates the output of the image sensor 1 into R, Y, and B signals, 3.4 is a video amplifier having a voltage ill-in type variable gain section, and 5 is an R - a differential amplifier for obtaining the Y signal;
6 is a differential amplifier for obtaining a BY signal, and 7 is an encoder.

White balance adjustment is performed by forming an image of a white or achromatic object through an imaging lens, converting this image into an electrical signal by an imaging cable 1, and further converting this signal into a separation circuit 2.
is converted into R, Y, and B signals by the video amplifier 3.
．． By controlling the gain of 4, the differential amplifier 5.
6<R-Y), the color difference signal of (B-Y) is made zero.

Next, FIG. 2 shows a circuit block diagram of a conventional camera device. In the figure, 8 is a photometric photodetector, 9° 10, 11 are photodetectors that detect each red, green, and blue light component, 12 is an amplifier for the output of the photometric photodetector, 13 is an exposure control circuit, 14.
15.16 is an amplifier for the photodetector output of each color component; 17.
18 is a differential amplifier, 19 is a lens, 20 is an aperture, 21 is a sheeter, 122 is a shutter control circuit, and 23 is an aperture 4.
It is a control circuit.

Lance adjustment with conventional white cameras uses detectors 9° io, i that detect red, green, and blue light components independent of the image sensor 1.
Obtain light component signals of each color from the subject corresponding to white using l, amplify them with amplifiers 14, 15, and 16, and then obtain light component signals of "red line" [blue-green J] with differential amplifiers 17 and 18. . The obtained optical component signal is used as a control signal to change the gain of the variable gain video amplifiers 3 and 4, and the separation circuit 2
The levels of the R and B video signals, which are output signals of
White balance adjustment is automatically performed by adjusting B-Y). Further, in the case of an electronic camera, since exposure control is necessary, a photometric photodetector 8 is provided for this purpose, and after this output signal is amplified by an amplifier 12, an exposure control circuit 13 is used to control the aperture v control circuit 23 and the shutter. The aperture 2o and shutter 21 are controlled by the control circuit 22.
and perform appropriate exposure control.

As described above, conventional electronic cameras require a photodetector for white balance control and a photodetector for exposure control, which has become a major problem as cameras become smaller and cheaper. There is.

Purpose of Light Amount The present invention solves the above-mentioned drawbacks of the conventional technology.It is possible to automatically adjust the white balance even when instantaneous image capture is performed using an electronic camera, improve operability and mobility, and reduce the size and cost of the camera. It is an object of the present invention to provide a camera device that can also improve image quality.

In order to achieve the object of Precept 1 of the invention, the camera device of the present invention includes a color image sensor, a plurality of photodetectors having mutually responsible spectral sensitivity characteristics independent of the color image sensor, and a plurality of these photodetectors. The color tfi of the illumination light is calculated by calculating the output signal of the photodetector of
[calculating means for obtaining information and light amount information; white balance control means for controlling the white balance of the output of the color image sensor based on the color temperature information from the calculating means; This configuration includes an exposure III control means for performing exposure control.

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

FIG. 3 is a circuit block diagram of a camera device according to an embodiment of the present invention, in which 24 is a color balance wA.
A photodetector that includes a wide-angle lens and is sensitive to short wavelength light (equivalent to blue), and 25 is a photodetector that is sensitive to long wavelength light (equivalent to red).
These photodetectors 24 are photodetectors with high sensitivity.
．． 25 is arranged so that it can capture subjects with a wide angle of view. 26.27 is each blue from the wide angle subject,
A photodetector 24 for detecting the red component; a logarithmic amplifier for amplifying the signals corresponding to each color of 25 regardless of the intensity of the light; 28 a consolidating amplifier for detecting the sum of signal levels of blue and red;
9 is a differential amplifier that detects the signal level difference between blue and red; 30 is an exposure control circuit; 31 is a voltage converter that converts the output of the differential amplifier 29 into necessary voltage characteristics; 32 is a lens;
33 is an aperture, 34 is a shutter, 35 is an 1111 image element, 36 is the output of the imaging probe 35 (Cy-Ma), and Y.

(Y-G) separation circuit, 31. 38 is a video amplifier that amplifies the output signal of the imaging probe 35 to a specified level. In this case, one of the video amplifiers 37 and 38, for example the video amplifier 37, has a voltage-controlled variable gain section and is controlled by the output signal of the voltage converter 31. 39 is an encoder for combining the video outputs of the video amplifiers 37 and 38 into a regular color signal, 40 is an aperture control circuit, and 41 is a shutter control circuit.

In a camera device configured in this way, when performing white balance adjustment at a certain color temperature as necessary, the photodetector 2 for blue (short wavelength light) and red (long wavelength light) is used.
4.25 allows a wide angle of view subject (equivalent to a white subject)
Detection outputs corresponding to each color component are obtained and amplified by corresponding logarithmic amplifiers 26 and 27, respectively.

At this time, the output of the differential amplifier 29 is transmitted to the photodetector 24.25.
Since the logarithmic amplifiers 26 and 27 are used as amplifiers for the output of , it is independent of the intensity of the incident light. Therefore, the output of the differential amplifier 29 at this time corresponds to a certain color temperature. Next, the output signal of the differential amplifier 29 is input to a voltage converter 31 that can convert and synthesize the required color temperature-voltage characteristics, and the output signal of the voltage converter 31 is used to convert the output signal of the voltage converter 31 into a video amplifier having a variable gain section. 37 gain control.

For example, if the video amplifier 31 is a video amplifier with a variable gain section, when a white or achromatic object is imaged for each color temperature, the video amplifier 31 is amplified so that the output levels of the video amplifiers 3γ and 38 are at the same level. It is necessary to control the gain of B37. The voltage converter 31 obtains the characteristics of the video amplifier 37 for the controlled color density 1a.

Furthermore, since the output signal of the additive amplifier 28 is the sum of the levels of the blue and red optical signals, it corresponds to the intensity of the required light.
By using this output signal, the exposure control circuit 3o does not require a special photometric photodetector for exposure control.
Accordingly, the aperture control circuit 4o and the shutter control circuit 41 can be activated to perform appropriate exposure control.

In this way, the photodetector 24°2 independent of the image sensor 35
5, it is possible to simultaneously and constantly obtain a signal corresponding to the color temperature that corrects white balance deviations at each color temperature and a signal corresponding to the incident light necessary to perform exposure control. It is also possible to automatically adjust the white balance, and also perform exposure control such as aperture control and shutter control.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, color temperature information and incident light amount information during photography can be simultaneously detected using a common photodetector without using a specific white subject. The white balance can be constantly and automatically adjusted at any time without changing the image, and exposure control can also be performed at the same time.
Therefore, the operability, size, and cost of the camera device can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the principle of white balance adjustment, FIG. 2 is a circuit block diagram of a conventional camera device, and FIG. 3 is a circuit block diagram of a camera device according to an embodiment of the present invention. 24, 25... Photodetector, 26.27... Logarithmic amplifier, 2B... Additive amplifier, 29... Differential amplifier, 3
0... Exposure control circuit, 31... Voltage converter, 35...
...Image sensor, 36...Separation circuit, 37, 38...
Video amplifier, 39... Encoder, 40... Aperture control circuit, 41... Shutter control circuit agent Hiroshi Moriki Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A color image sensor, a plurality of photodetectors independent from the color image sensor and having mutually different spectral sensitivity characteristics,
An extraction means for calculating the output signals of the plurality of photodetectors to obtain color temperature information and light amount information of the illumination light, and a white balance &1Jill of the output of the color image sensor based on the color temperature information from the extraction means. and an exposure control means that performs fog light control of the color image sensor based on the light amount information from the calculation means. Claim 1: A subtracter that obtains a difference signal between output signals of a plurality of photodetectors; and an adder that obtains a sum signal of output signals of a plurality of photodetectors to obtain light amount information. Camera equipment as described. 3. The plurality of photodetectors are composed of a first photodetector that is mainly sensitive to red light and a second photodetector that is mainly sensitive to blue light, and and the color temperature information from the difference signal of the output signal of the second photodetector.
A camera device according to claim 1, which is configured to obtain information. 4. The white balance control means changes the difference signals of the plurality of photodetectors into the required color temperature-voltage characteristics. 1′! 2. The camera device according to claim 1, having a configuration including a voltage converter.