JPH0229191A - Image pickup device - Google Patents

Abstract

PURPOSE:To completely control white balance for every color temperature of an object by providing a mode to fix control of the white balance and controlling the white balance regardless of a limited range for correction at the time of the fixing mode. CONSTITUTION:A microcomputer 10 composes a white balance control part, controls the white balance by automatically correcting the white balance, has a limiting mode to add limitation to automatic tracking type white balance control and the fixing mode to fix the white balance control by a standard white plate, etc., and selects the respective modes with a change-over switch 16. Further, the microcomputer 10 executes fixed control regardless of the limited range at the time of the fixing mode. Thus, the complete white balance control can be executed for every color temperature.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is particularly applicable to TTL (Through the
The present invention relates to a color imaging device that performs automatic tracking type white balance control using the Lens method.

[Conventional technology]

2. Description of the Related Art Color imaging devices that perform automatic tracking type white balance control using a TTL method are conventionally known. In this device, white balance correction control is automatically performed based on imaging information of a subject passing through a lens. At that time, if there is no completely white part in the subject or if the background that occupies a large area is a uniform color other than white,
If you control the white balance based on the high-brightness part of the subject or the average value of the video signal (chroma signal) of the whole subject, when you transfer the image of the subject to the monitor, you can make sure that the part outside the white breath becomes white. control. As a result, the white balance within the monitor screen will be disrupted.

Therefore, in order to improve the above points, for example, the white balance correction range (control range) is stored as a table in the microcomputer that performs white balance control, and the white balance is adjusted within the correction range limited by this table. It is possible to control it. that time,
Control is performed to narrow the correction range mainly for magenta and green (green) directions. Effective control can be performed for colored subjects.

[Problem to be solved by the invention]

However, in the above-mentioned imaging devices, the white balance is controlled within a limited correction range, so for example, when capturing an image of a subject with many white parts, or using a white standard plate, it is difficult to completely adjust the white balance. When shooting at the same time, the correction range is limited, so it is possible to achieve perfect white balance for all color temperatures of the subject.
(There was also the problem that I could only control I.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an imaging device that can perform complete white balance control for all color temperatures of five objects.

[Means to solve the problem]

The imaging device of the present invention has a limited mode in which the white balance correction range is limited and controlled for each color temperature of the subject;
A fixed mode is provided to fix white balance control.
In the fixed mode, the white balance is fixedly controlled regardless of the Moeki limited range.

[Effect]

In the imaging apparatus of the present invention, a mode is provided in which white balance control is fixed, and in the fixed mode, IIJ511 is performed regardless of the limited range of correction. Therefore, complete white balance control is performed for all color temperatures of the subject.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an imaging device according to the present invention, showing the main parts of a color imaging device that performs automatic tracking type white balance control using the TTL method.

In FIG. 1, 1 is a lens into which the imaging light of the subject is incident, 2 is an image sensor that converts the incident light into an electrical signal,
Many devices such as CCD, MO3 type device, tube type image sensor, etc. can be used. 3 and 4 are amplifiers that amplify the signals from the image sensor 2; here, R among the three primary color signals;
(red) signal and B (blue) signal are amplified. 5 is the above R
, G (green), and B are input, R-Y, B-Y
6 is an encoder that outputs video No. 13 to a monitor (not shown) based on the RY signal, BY signal, and Y signal from the process section 5. , 7 is a clock ICl that provides clock pulses for driving and controlling each part. 9 is an R, G clock output from the microcomputer 10 for white balance control.
This is a converter that converts the gain control signal of
Then, the RY signal, BY signal, and Y signal are processed, and as a result, the above gain control signal is output.

Then, by this gain control signal, the amplifier 3.4
gain is controlled. 11. 12 is an integrating amplifier which integrates and amplifies the R-Y signal and B-y Iz signal outputted from the process section 5, respectively, and manually inputs them to the microcomputer 10; 13 is a BIC detection device which detects the peak value of the Y signal. The circuits 14 and 15 are sample-and-hold circuits that sample and hold (S/H) the values of the R-Y signal and B-Y signal using the output signals of the peak detection circuit 13, respectively, and manually input the values to the microcomputer 10, and 16 is a sample-and-hold circuit that will be described later. This is a mode changeover switch for switching between a limited mode and a fixed mode of white balance control.

The microcomputer 10 constitutes a white balance control section, and is configured to automatically correct white balance and perform @ control. This white balance control has the aforementioned limited mode and fixed mode. The limited mode is a mode in which the white balance correction range is limited and controlled for each color temperature of the subject, and the correction value is stored in the microcomputer 10. is stored in memory as a table. In addition, the fixed mode is a mode in which the white balance is completely maintained at any color temperature using a white cap or white paper, and the control is fixed. In this fixed mode, the white balance is set in the microcomputer 10 regardless of the above-mentioned limited range; It is used to the limit of the control range and is fixedly controlled.

Next, the operation will be explained.

When the imaging light of the object enters the light receiving section of the image sensor 2 through the lens 1, the image sensor 2 outputs R, G, and B color signals in synchronization with the above-mentioned clock pulse. This R,
The G and B signals are input to the processing section 5, where, as described above, the R-Y and B-Y color difference signals and the luminance signal (Y signal) are processed.
is formed. Then, these R-Y signal, B-Y signal and Y signal are inputted to the encoder 6, where the R-Y signal and B-Y signal are modulated by clock pulses and then Y
It is mixed with the signal and output as a video signal.

In the signal processing process by the process section 5, the R-Y(3) and B-Y signals output from the process section 5 are integrated and amplified, respectively, and input to the microcomputer 10 as described above.

Further, in the Y signal, the peak detection circuit 13 detects the portion where the signal level is higher than the threshold level as the peak value.
The detection pulse (output pulse) is supplied to sample and hold circuits 14 and 15. Then, when the above peak value is detected by this sample hold circuit 14.15, R-
The levels of the Y signal and BY signal are read and output to the microcomputer 10.

Here, the microcomputer 10 that controls the white balance switches to the above-mentioned limited mode (TTL automatic tracking white balance control mode). At this time, microcomputer 10
reads the color difference integral signal from the integrating amplifier 11.12 and the value of the color difference signal from the sample hold circuit 14.15, executes program arithmetic processing, and outputs R and B gain control signals.

FIG. 2 shows the white balance correction control range in the limited mode. The shaded area (A) in the figure is the correction control range, which is stored in the memory of the microcomputer 10 as a table. This correction control range is
It is a limited range from the area of nXn (LSB) which is the limit control range of 0, and within this limited correction control range, the gain control signal of R9B is
．． The signal is inputted to the process unit 5 via 9. In this way, in the processing section 5, feedback is applied to the R signal and the B signal, and the levels of the R and B signals are controlled each time, and the level of the color difference signal to be the output signal is adjusted.

White balance control is performed by adjusting the level of this color difference signal.

The microcomputer 10 also has a changeover switch 16.
When the contactor is in contact with the b side and in a grounded state, a fixed mode control is performed in which the white balance is completely fixed at the color temperature at that time using a white cap or white paper. At this time, as shown in Fig. 3, the correction control range (b) of the microcomputer 10 is the entire area of nxn (LSB), which is the limit control range, and all colors are available regardless of the correction control range (a). You can perfectly white balance the temperature.

In this way, there is a limited mode in which automatic tracking type white balance control using the TTL method is limited, and a fixed mode in which white balance control is fixed using a standard white plate, etc., and each mode can be freely selected using the changeover switch 16. Allowing you to choose. Therefore, the limited mode allows optimal white balance control to be performed to suit all conditions of the copying material, and the fixed mode fixes the gain control signal, making it possible to perform perfect white balance control even when shooting at a wide range of color temperatures. You can perform accurate white balance control.

FIG. 4 is a flowchart showing an example of a white balance control operation performed by the microcomputer 10 mentioned above.

First, in step S1, the mode is determined based on a signal from the mode changeover switch 16. At this time, if it is the limited mode, the color difference integral 13 is output from the integrator 11 and 12 in step S2.
At the same time as inputting the signal, the sample and hold circuit 14.15
Input the color difference signal at the peak of the luminance signal from next,
In step S3, the aforementioned program calculation is executed using these No. 43 values, and in step S4, R and B gain control signals are output based on the processing results. Then, in step S5, it is determined whether or not the above-mentioned signal is input from the process section 5, and if there is no human input signal, this operation is ended.

Further, if it is determined in step S1 that the fixed mode is set, the process moves to step S6, where the correction control range in the limited mode described above is canceled. Then, in step S7, white balance is taken using a standard white plate and white balance control is fixed.

〔Effect of the invention〕

As described above, according to the present invention, there are provided a limited mode in which white balance correction range is limited and controlled, and a fixed mode in which white balance control is fixed, and in fixed mode, fixed control is performed regardless of the limited range. Because of this,
Optimal white balance control can be performed to suit every situation of the copy, and complete white balance control can be performed for all color temperatures.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an imaging device according to the present invention, FIG. 2 is an explanatory diagram showing a correction control range in limited mode,
FIG. 3 is an explanatory diagram showing a correction control range in fixed mode, and FIG. 4 is a flowchart showing an example of white balance control operation. 1...Lens 2...Image sensor 3.4...Amplifier 5...Process section 6...Encoder 7...・Clock IC 8, 9... Converter 10... Microcomputer (white balance control section) 11.12... Integrating amplifier 13... Peak detection circuit 14.15...Sample hold circuit 16...
...mode changeover switch

Claims (1)

[Claims] Imaging devices that perform white balance correction control have a limited mode that limits and controls the white balance correction range for each color temperature of the subject, and a fixed mode that fixes white balance control. An imaging device characterized in that fixed control is performed regardless of the limited range.