JPS61128694A - Electronic still camera device - Google Patents

Abstract

PURPOSE:To enlarge an effectiveness of a control, an operability and a mobility of a white balance by detecting a luminous light of a flash device and selecting a color temperature information of a circumferential light and a color temperature of a flash light according thereto. CONSTITUTION:When a flash device 16 generates a luminous light, the luminous light is detected in a luminous light detecting circuit 31, and a color temperature information change-over switch SW13 is changed over to a flash color temperature information generating circuit 11 side. According to the flash color temperature information selected by the SW13, gains of amplifiers 25, 26 are changed, levels of image signals of output signals R, B of a separating circuit 24 are controlled to adjust outputs R-Y, B-Y of amplifiers 27, 28 and a white balance is controlled. When the flash device 16 generates no luminous light, since the circuit does not detect the luminous light, the SW31 is as it is changed over to a hold circuit 30 side. By the color temperature information according to a circumferential light held by a circuit 30, the gains of the amplifiers 25, 26 are changed to control the white balance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to white balance control of an electronic still camera device.

Prior Art FIG. 3 shows a block diagram of a conventional electronic still camera device. In the figure, 1 is a photometric light detection section, 2.3.
4 is a photodetector that detects each red, green, and blue light component; 6 is an amplifier for the photodetector signal for photometry; 8 is an amplifier for the photodetector signal for each color component; 9゜1o is the difference 11 is a color temperature information generation circuit corresponding to the color temperature of flash light, 12 is a shooting mode switching SW for normal shooting and flash photography, 13 is a color temperature information switching SW, 14 is a hold circuit for the output of the switching SW circuit,
15 is an exposure control circuit, 16 is a flash device, 1 is a flash control circuit, 18 is an aperture control circuit, 19 is a shutter control circuit,
20 is a lens, 21 is an aperture, 22 is a shutter, 23 is an image sensor, 24 is a separation circuit that separates the output of the image sensor into R, Y, and B signals, 25. 26 is an image amplifier having a voltage-controlled variable gain section. , 27 is a differential amplifier for obtaining the R-Y signal, 28 is a differential amplifier for obtaining the B-Y signal,
29 is an encoder.

FIG. 4 is a timing chart showing the timing of each part of a conventional electronic still camera device. a is the shutter opening/closing signal, b is the timing when the variable gain video amplifier 25 or 2e performs color temperature correction signal processing, C is the switching command signal for the color temperature information switching 5W13, and d is the output of the differential amplifier 9 or 10. , e are control signals used for color temperature correction signal processing.

The operation of the conventional electronic still camera device configured as described above will be explained below. When performing white balance adjustment, the red, green, and blue photodetectors 2°3.4 provide detection outputs corresponding to each color component from the subject that corresponds to white, and output signals independent of the intensity of the incident light. In order to
``red-green'' and ``blue-green'' optical component signals are obtained. For flash photography, a flash color temperature information generating circuit 11 obtains a control signal corresponding to the color temperature of the flash.

The two control signals are input to the color temperature information switch 5W13, and one of the two control signals is selected according to the photographing mode switch SW12 shown in FIG. 4C. The selected control signal is held in the hold circuit 14 by the shutter open/close signal shown in FIG. 4a, and is held until the signal processing timing shown in FIG. 4a. Then, the output of the hold circuit 14 shown in FIG.
R2B, which is the output signal of the separation circuit 24, changes the gain of
The differential amplifier 27°28
White balance adjustment is performed by adjusting the outputs of R-Y and B-Y.

However, in the above configuration, the shooting mode switching 5
Since the color temperature information switch 5W13 is switched by the output of W12, if the flash does not fire due to incorrect operation of the shooting mode switch, incorrect operation of the flash, or insufficient charge of the flash, it is possible to check whether or not the flash is firing. Irrespective of this, one of the two color temperature information will be selected depending only on the state of the photographing mode switching 5W12, so the white balance will not be controlled correctly. In addition, especially when using an auto-adjustable flash device that controls the amount of light emitted according to the brightness of the subject, the brightness of the subject may be bright even if the shooting mode switch 5W12 is set to the flash shooting side. In this case, the flash color temperature information generation circuit 1 is activated by the color temperature information switching 5W13 even though the flash is not emitted in the above configuration.
1 is selected, the variable gain type video amplifiers 25 and 26 are controlled by a control signal corresponding to the color temperature of the flash, resulting in a problem that correct white balance control cannot be performed.

In view of the above problems, the present invention detects the presence or absence of a flash of light, selects the color temperature information of the ambient light and the color temperature information of the flash of light, and selects the color temperature information of the ambient light and the color temperature information of the flash of light accordingly. Reliable white balance adjustment by controlling the balance.

An object of the present invention is to provide an electronic still camera device that can improve operability 1 and maneuverability as photographing conditions change.

Means for Solving the Problems The electronic still 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 means for holding the color temperature information until a time when a still image signal is read out and signal processing; means for controlling white balance of the output of the color image sensor based on the color temperature information; and means for detecting flash light emission. and the means for obtaining color temperature information of the illumination light includes means for detecting color temperature information of ambient light and means for generating color temperature information corresponding to the color temperature of flash light, The output of the information generating means is selected according to the output of the light emission detecting means.

Function: With the above-described configuration, the present invention detects light emission from the flash unit and selects color temperature information for white balance control accordingly. This eliminates white balance control failures caused by incorrect operation, etc., and also eliminates white balance control failures caused by the flash not firing due to brightness of the subject when using an auto-adjustable flash. Reliability of white balance control as white balance is controlled accordingly.

Operability 2: Mobility can be improved.

EXAMPLE An example of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing the configuration of an electronic still camera device according to an embodiment of the present invention, and the same components as those shown in FIG. 3 are given the same numbers and their explanations will be omitted. FIG. 2 is a timing chart showing the timing of each part of the electronic still camera device according to the present invention. In the figure, a is the opening/closing signal of the shutter, b is the timing at which the variable gain video amplifier 25 or 26 performs color temperature correction signal processing, C is the light emission state of the flash device 16, and d is the switching command for the color temperature information switch 5W13. The signal /e is the output of the differential amplifier 9 or 10, and f is the control signal used for color temperature correction signal processing. The outputs of the differential amplifiers 9 and 1o are sent to the hold circuit 3 in synchronization with the shutter open/close signal shown in FIG. 2a.
0, and is held until the signal processing timing shown in FIG. When the flash unit 16 emits light as shown in FIG. 2C, the light emission detection circuit 31 detects the light emission and the color temperature information switch 5W13 is switched to the flash color temperature information generating circuit 11 side as shown in FIG. 2D. and Figure 2 d
As shown in the figure, the level of the R and B video signals, which are the output signals of the separation circuit 24, is controlled by changing the gains of the variable gain video amplifiers 25 and 26 according to the flash color temperature information selected by the color temperature information switching 5W13. The white balance is controlled by adjusting the outputs of the differential amplifiers 27 and 28, RY and BY.

Next, a case where no flash is emitted will be explained.

As shown in FIG. 2d, the color temperature information switch 5W13 is switched to the hold circuit 30 side at the same time as the shutter is opened in FIG. 3d. If the flash device 16 does not emit light, the light emission detection circuit 31 does not detect light emission, so the color temperature information switching SW is directly switched to the hold circuit 3° side. Then, at the timing shown in FIG. 2, the white balance is controlled by changing the gains of the variable gain video amplifiers 25 and 28 based on the color temperature information corresponding to the ambient light held in the hold circuit 3o.

As described above, according to this embodiment, the light emission from the flash device is detected and the color temperature information is selected accordingly.
Since the shooting mode switching switch between normal shooting and flash photography for selecting color temperature information can be removed, operability 1. Mobility can be greatly improved, and white balance control failures due to erroneous operations can be eliminated. I can do it. What's more, when using an automatic dimmer, even if the flash output changes depending on the brightness of the subject, the flash output is always detected and color temperature information is selected, ensuring reliable white balance control. can be significantly improved.

Effects of the Invention As described above, according to the present invention, since the light emission from the flash device is detected and the color temperature information of the ambient light and the color temperature information of the flash light are selected accordingly, the reliability of white balance control is improved. , operability 9 mobility can be greatly expanded.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an electronic still camera device according to an embodiment of the present invention, FIG. 2 is a timing diagram of each part thereof, and FIG. 3 is a block diagram showing the configuration of a conventional electronic still camera device. FIG. 4 is a timing diagram of each part. 2.3.4...Color component detection photodetector, 9,10
... Differential amplifier, 11 ... Flash color temperature information generation circuit, 13 ... Color temperature information switching SW,
16...Flash device, 23...Image sensor,
24... Separation circuit, 25° 26... Variable gain video amplifier, 27.28... Differential amplifier, 30... Hold circuit, 31...・・・・・・
Luminescence detection circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 0□ Figure 3 Figure 4

Claims (1)

[Claims] 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;
means for holding the color temperature information until a time when the accumulated still image signals are read out and signal processing; means for controlling the white balance of the output of the color image sensor based on the color temperature information; and means for controlling the emission of flash light. and the means for obtaining color temperature information of the illumination light includes means for detecting color temperature information of ambient light and means for generating color temperature information corresponding to the color temperature of flash light, An electronic still camera device characterized in that the white balance control is performed by selecting the outputs of the two color temperature information generating means according to the output of the flash light emission detecting means.