JPH10304386A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the effect of an object on white balance in the case of conducting both focus lock and white balance setting with one switch simultaneously. SOLUTION: An AF frame 201 and 48 sets of AWB frames 202 are provided in a photographed screen 200, and in the case of conducting focus lock and white balance setting with one switch simultaneously, the white balance is taken and locked based on an AWB evaluation value of the AWB frames 202a which are not overlapped on the AF frame 201, and focus is controlled based on the AF evaluation value of the AF frame 201 and locked to the focusing state. Thus, the effect on the object in the AF frame at the white balance control is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an imaging apparatus such as a video camera for performing white balance control and focus control.

[0002]

2. Description of the Related Art AWB, AE, AF and the like, which are basic auto functions at the time of shooting with a video camera, can control the control operation of each auto function in order to cope with various shooting conditions. When the video camera is pointed at a reference object that can be corrected manually or when a switch is pressed, the function is set to the most appropriate state for shooting that object in each function, and that state is maintained. (Fixed). In particular,
On / off of AF function (focus lock), auto / lock of AE function (AE lock), correction of focal length by dial keys etc. after AF function is off, subject to shooting is unconditionally determined to be white White balance adjustment (a function called white balance set or one-push AWB, which is different from a white balance lock in which a white balance control operation is simply stopped like a focus lock or an AE lock).

On the other hand, in recent years, the demand for recording a still image for inputting an image to a personal computer or the like has increased, and accordingly, video cameras equipped with a still image recording function have been increasing. In such a video camera, the AE, AF, AWB function (silver film film) is performed by half-pressing a switch (trigger key) for executing still image recording when recording a still image, such as a silver halide film camera. Cameras do not have AWBs), but focus and exposure, which were automatically controlled according to the subject, and even white balance, are simultaneously fixed (locked) to the state when they are half-pressed. .

[0004]

However, as described above, the focus lock and the A
No problem occurs when executing the white balance at the same time as E-lock, but a problem occurs when executing the white balance set at the same time. This problem will be described with reference to FIG.

FIG. 8 shows an image pickup screen obtained by photographing with a video camera. A frame (AF frame) 201 in the image pickup screen 200 is used for distance measurement, and the AF function is performed for a subject (person in FIG. ) 203 is controlled to be in focus. Here, when the focus lock and the white balance set are simultaneously executed by the switch which also functions as the focus lock and the white balance set, the focus is fixed in a state where the subject in the frame is in focus by one operation of the switch, and the white balance is set. As for the balance, the white balance is forcibly adjusted based on information from the entire screen including the subject, and the adjustment state is fixed after the adjustment. Therefore, FIG.
In such a subject, the influence of the subject on the white balance becomes strong. In particular, when a person is a subject, the skin color and the like are very similar to white at a low color temperature, and this becomes remarkable. In some cases, white balance control is performed so that the skin color is completely faded.

Normally, when performing white balance setting, it is basically to take an image of a white subject (for example, a blank sheet) over the entire screen. However, if this is to be executed in the above case, the white balance adjustment will be performed well. Even if
Since it is fixed out of focus, it has no meaning at all.

The present invention realizes both focus lock and white balance setting by one operation of one switch, not by separate operations, and solves the above-mentioned problem. An object is to obtain good focus control and white balance control.

[0008]

According to the present invention, there is provided an image pickup means for picking up an object image and outputting an image signal, a lens means for forming the object image on an image pickup screen of the image pickup means, and an image pickup means. A focus control unit that performs focus control of the lens unit based on a signal obtained from a first area set at a predetermined position on the imaging screen among the obtained image signals; and a focus control unit that performs focus control on the image signal obtained from the imaging unit. White balance control means for performing white balance control of the image signal based on a signal obtained from a second area set at a position not overlapping with the first area of the imaging screen; and the focus control and white balance control And switch means for giving instructions to the focus control means and the white balance control means so as to simultaneously perform That.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing an imaging device, FIG. 2 is a diagram showing an AF frame, FIG. 3 is a diagram showing a first AWB frame, FIG.
FIG. 5 is a diagram showing a positional relationship between the AF frame and the AWB frame, FIG. 5 is a diagram showing an AWB frame used in the first white balance set, and FIG.
FIG. 7 is a diagram illustrating a WB frame, and FIG. 7 is a diagram illustrating a second AWB frame.

In FIG. 1, reference numeral 101 denotes a lens group for forming an image of a subject; 102, an aperture for adjusting the amount of light; 103, an image pickup device such as a CCD for converting input light into an electric signal;
04 is a sample and hold unit for performing sample and hold, 105 is an AGC unit for automatically controlling gain, 106
Is analog-to-digital conversion (hereinafter A / D conversion)
/ D converter 107, a motor for driving the lens group 101, 108 a motor driver for driving the motor 107,
Reference numeral 109 denotes a camera signal processing unit that generates a color signal and a luminance signal by processing signals, 110 denotes a video signal generation unit that generates a video signal, 111 denotes a system control unit that controls the entire imaging device, and 112 denotes a switch unit. .

In the camera signal processing unit 109, 10
Reference numeral 01 denotes a Y / C separation unit that separates an input signal into a luminance (hereinafter referred to as Y) component and a color (hereinafter referred to as C) component, and 1002 denotes a C component signal as red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B). ), A C-separation unit for separating into white components,
B) WB unit for adjustment; 1004, a C signal processing unit for performing predetermined signal processing; 1005, a color difference signal (RY)
Signal, a color difference matrix section for generating a (BY) signal, 1
Reference numeral 006 denotes a modulation unit for performing modulation, 1007 and 1010 denote D / A conversion units that perform digital-analog conversion (hereinafter, D / A conversion), 1008 denotes an LPF unit that is a low-pass filter (hereinafter, LPF), and 1009 denotes a predetermined signal. A Y signal processing unit 1011 that performs processing performs A processing that performs signal processing for AF control.
An F signal processing unit 1012 is a WB signal processing unit that performs signal processing for WB control, 1013 is a gate signal generation unit that generates a gate signal, and 1014 is a camera signal processing unit 109.
The interface unit is a data input / output unit.

Next, the operation will be described. Lens group 10
The light from the subject received from 1 is adjusted in light quantity by the aperture 102 and is formed on the imaging screen of the imaging element 103. Here, after being converted into an electric image signal, the A / D signal is passed through a sample-and-hold unit 104 and an AGC unit 105.
A / D conversion is performed by the conversion unit 106, and the camera signal processing unit 10
9 is input. In the camera signal processing unit 109, the input signal is separated into a C component and a Y component by a Y / C separation unit 1001, and the C component is output to a C separation unit 1002 and the Y component is output to an LPF unit 1008.

[0013] In the C separating section 1002, the signal of the C component is R,
The WB unit 1003 performs WB adjustment by adjusting the gains of the R component and the B component. The adjustment of the gain is under the control of the system control unit 111. At this time, the gain of the G component is fixed to a predetermined value. WB
The adjusted signals are supplied to the C signal processing unit 1004 and the color difference matrix unit 1005 via the color difference signals (RY), (B-
Y) signal. The color difference signals (RY) and (BY)
The signal is input to modulation section 1006 and WB signal processing section 1012. The modulation section 1006 outputs a color difference signal (R-
A 3.58 MHz signal is modulated by the (Y) and (BY) signals. At this time, a color burst signal as a color synchronization signal is added. Further, after being D / A converted by the D / A conversion unit 1007, it is output to the video signal generation unit 110 as a color signal.

On the other hand, from the Y component signal input to the LPF section 1008, only the low frequency components of the signal are extracted and output to the Y signal processing section 1009 and the AF signal processing section 1011. The signal via the Y signal processing unit 1009 and the D / A conversion unit 1010 is output to the video signal generation unit 110 as a luminance signal.

The gate signal generation unit 1013 generates a gate signal for extracting a signal in a frame (hereinafter referred to as an AF frame 201) in an image screen 200 shown in FIG. 2 imaged under the control of the system control unit 111. AF signal processing unit 1
011. Screen 2 as shown in Fig. 3
A gate signal for extracting a signal in each frame is generated in a frame that divides 00 into 48 (hereinafter referred to as a first AWB frame 202), and is output to the WB signal processing unit 1012. In the AF signal processing unit 1011, the signal from the LPF unit 1008 is gated with the gate signal from the gate signal generation unit 1013,
AF for AF control by processing the signals in the frame 201
Generate an evaluation value. The WB signal processing unit 1012 converts the signal from the color difference matrix unit 1005 into the gate signal generation unit 1
013 and gate each AWB
Processing is performed for each frame 202 to generate a WB evaluation value for WB control. FIG. 4 shows the AF frame 201 and the first AWB frame 2
It shows a positional relationship with 02, and 203 is a subject.

The AF evaluation value and the WB evaluation value are read by the system control unit 111. Camera signal processing unit 109
Input and output of signals (data) between and the system control unit 111 are performed via the interface unit 1014. D
The color signal from the A / A converter 1007 and the D / A converter 101
The video signal generator 110 generates and outputs a video signal based on the luminance signal from 0.

The motor driver 108 generates a motor drive signal under the control of the system control unit 111, and the motor 107 drives the lens group 101 based on the drive signal. Various switches for the photographer to operate the imaging apparatus are arranged in the switch unit 112, and a switch (hereinafter referred to as AF lock / WB) for simultaneously executing the focus lock and the white balance set is arranged in the arrangement of these switches. Set switch) is also included. The setting states of these switches are read by the system control unit 111.

Next, the operation of the AF and AWB functions by the AF lock / WB set switch will be described.
The imaging apparatus according to the present embodiment has an auto mode and an AF mode.
Lock / WB set mode is possessed, and the two modes are switched by turning on / off the AF lock / WB set switch. When the power is turned on, the AF and AWB functions are in an on state (hereinafter, an auto mode), and the focus control and the WB control are all performed automatically. In the auto mode, the system control unit 1
Numeral 11 controls the motor driver 108 based on the AF evaluation value in the AF frame 201 from the AF signal processing unit 1011 so that the subject in the AF frame 201 is always focused. Also, 48 first AWs from the WB signal processing unit 1012
Based on the WB evaluation value in each frame of the B frame 202, the WB unit 1003 in the camera signal processing unit 109 is controlled to always have an appropriate WB. At this time, the 48 AWB frames 202
Is determined for each frame as to whether it is white, and as a result, only the WB evaluation value of the frame determined to be white is used. This state is maintained until the AF lock / WB set switch is turned on and the mode is switched.

Next, when the AF lock / WB set switch is turned on, the focus is locked and the WB
To the AF lock / WB set mode in which is set. In this AF lock / WB set mode,
The system control unit 111 controls the motor driver 108 to fix the focal position. Further, the AWB frame 202a of the hatched portion which does not overlap with the AF frame 201 of the first AWB frame 202 shown in FIG.
The WB unit 1003 in the camera signal processing unit 109 is controlled based on the (32 frames) WB evaluation value. At this time 3
The WB evaluation values of the two AWB frames 202a are unconditionally determined to be white and adjusted so as to obtain an appropriate WB, and the WB adjustment state is fixed after the adjustment. This state is maintained until the AF lock / WB set switch is turned off and the mode is switched. As a matter of course, it is desirable that there be a white subject including the background in the frame (AWB frame 202a) of the first AWB frame 202 to be used.

The AF frame 201 and the first AWB frame 202
If the overlapped portion is slight and does not substantially affect each other, the AWB of the hatched portion as shown in FIG.
The WB evaluation value of the frame 202a (40 frames) may be used. In addition, the first AWB frame 202 is the screen 20 here.
Although 0 is divided into 48 parts, the present invention does not limit the number and shape of the frames.

Further, in the AF lock / WB set mode, the first AWB frame 202 obtained by dividing the screen 200 is not output, but as shown in FIG.
02b may be output. At this time, too, the setting position of the AWB frame 202b is, of course,
This is a position that does not overlap with 1. In FIG. 7, one AW
Although the B frame 202b is set, the number and shape of the frame are not limited in the present invention. Although the present embodiment has been described for a video camera, it is needless to say that the present invention is also effective for a digital camera and the like.

[0022]

As described above, according to the present invention, when the white balance set is executed simultaneously with the focus lock by one operation of one switch, for example, even in a shooting situation as shown in FIG. The influence of the subject on the white balance adjustment can be eliminated, and good focus control and white balance control can be performed simultaneously. Also, even if a subject such as a blank sheet is placed in the imaging screen to more reliably perform the white balance setting, it is not necessary to put a blank sheet on the entire screen. It does not affect the settings.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an imaging device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an AF frame.

FIG. 3 is a configuration diagram illustrating a first AWB frame.

FIG. 4 is a configuration diagram illustrating a positional relationship between an AF frame and a first AWB frame.

FIG. 5 is a configuration diagram illustrating an AWB frame used in white balance setting.

FIG. 6 shows another AW used for white balance setting.
It is a block diagram showing a B frame.

FIG. 7 is a configuration diagram showing a second AWB frame.

FIG. 8 is a configuration diagram showing a positional relationship between a conventional AF frame and an AWB frame.

[Description of Reference Numerals] 101 lens group 103 imaging element 107 motor 108 motor driver 109 camera signal processing unit 111 system control unit 112 switch unit 200 imaging screen 201 AF frame 202 202a first AWB frame 202b second AWB frame 1001 Y / C separation unit 1003 WB unit 1011 AF signal processing unit 1012 WB signal processing unit 1013 Gate signal generation unit

Claims (4)

[Claims] An imaging unit configured to capture an image of a subject and output an image signal; a lens unit configured to form the subject image on an imaging screen of the imaging unit; and the imaging screen among image signals obtained from the imaging unit. A focus control unit that performs focus control of the lens unit based on a signal obtained from a first region set at a predetermined position of the first region; and a first region of the imaging screen in an image signal obtained from the imaging unit. White balance control means for performing white balance control of the image signal based on a signal obtained from a second area set at a position which does not overlap with the image signal; and the focus so that the focus control and the white balance control are performed simultaneously. An imaging apparatus comprising: a control unit; and a switch unit for giving an instruction to the white balance control unit. 2. The image processing apparatus according to claim 1, wherein the white balance control unit divides the imaging screen into a plurality of frames, and sets a frame that does not overlap the first region among the frames as the second region. The imaging device according to claim 1. 3. The switch means determines a first mode in which white balance control and focus control based on a signal obtained from the second area are simultaneously performed, and a first mode for each of the plurality of frames. 3. The imaging apparatus according to claim 2, wherein the imaging apparatus selectively designates a second mode in which white balance control based on a white balance evaluation value and the focus control are simultaneously performed. 4. In the second mode, the white balance control means performs white balance control based on a white balance evaluation value determined to be white among white balance evaluation values obtained for each of the frames. The imaging device according to claim 3, wherein: