JP2003319406A - Video camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform stable, accurate white balance control from a time of starting actual recording operation in a video camera having a power save mode. <P>SOLUTION: In the video camera having the power save mode when a power switch is turned on and the camera is in the power save mode, a push of a record button causes actual recording operation to start after the camera is set to a suitable exposure level. During a time from actual push of the record button until the recording operation is actually started, operation of a full-screen integral type is carried out at a high speed as white balance control calculation. After the actual recording is started, operation of a divided screen integral type is carried out at a low speed as the white balance control. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera, and is devised so that accurate and stable white balance control can be performed when actual recording is started.

[0002]

2. Description of the Related Art In a video camera, white balance is controlled so that a white reproduced image can be obtained when a white subject is photographed. The white balance is controlled by adjusting the gains of the red signal circuit and the blue signal circuit of the camera with reference to the green signal.

An image integration type auto white balance circuit in the auto white balance (AWB) circuit is controlled based on the knowledge that when the color signal components of the entire image pickup screen are integrated, an achromatic color is obtained.

In the image integration type auto white balance circuit, color signal components are integrated. At this time, a full screen integration type in which all color signals of the entire screen are captured and integrated, and the screen is divided into a plurality of areas. , There is a split screen integration type that takes in and integrates color signals for each area.

An outline of the split screen integration type will be described with reference to FIG. As shown in FIG. 3, the screen is 20
The area is divided into (= 5 × 4) areas (reference numerals a1 to a20 are given to indicate each area. Actually, the number of divisions is large in order to improve the accuracy, but the description is simplified. An example of 20 divisions will be described.). Then, in the first vertical scanning period (hereinafter abbreviated as “V period”), the signal component of the area a1 is integrated to obtain an integrated value i1, and in the second V period, the signal component of the area a2 is integrated to obtain an integrated value i2. Similarly, the integration calculation of the areas a3, a4, a5 ... Is continued every 1V period, and the integrated value i20 of the area a20 is obtained in the 20th V period. Then, data that is substantially white is selected from the integrated values i1 to i20, the color temperature of the subject is detected using the selected data group, and white balance control is performed. In this way, since the white balance control is performed by selecting the data of the area that is substantially white, the divided screen integration type is generally more accurate than the full screen integration type.

[0006]

By the way, in the integrator of the IC mounted on the video camera incorporating the present invention,
The integral calculation can be performed only once in the V period (= 1 field period). Therefore, in the split screen integration type auto white balance, it takes a time of "1 V period × the number of divided areas" to perform the white balance control once, and there is a problem that it is not possible to follow a rapid change in color temperature. . In the full screen integration type, data calculation for white balance control can be performed in the 1V period.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a video camera having a power save mode, which is capable of performing accurate auto white balance control immediately after the start of recording.

[0008]

According to the video camera of the present invention for solving the above problems, when the recording button of the video camera is turned on, the automatic white balance control is performed in the first mode for a predetermined period after the recording button is turned on. After that, the automatic white balance control is performed in the second mode.

In this case, the predetermined period is a preset fixed time period, or the predetermined period is a time period from when the recording button is pressed until the actual recording is started, or when the actual recording is started. It is characterized by starting on the condition that the iris is stable.

Further, the video camera of the present invention receives an image signal corresponding to a picked-up image, divides the picked-up screen into a large number of areas, and can output an image signal in one area for one field period, and A screen having a screen division mode in which one area capable of outputting an image signal is sequentially shifted in a cycle of one field period, and a full screen mode in which all image signals contained in one screen are output in one field period The image signal is output based on the dividing unit, the integrating unit that integrates the image signal output from the screen dividing unit and outputs the integrated value for each field period, and the integrated value output from the integrating unit. A control unit that determines whether or not the average of the images on the screen is substantially white, and outputs a white balance control signal according to the integrated value when it is determined to be substantially white,
An auto white balance device having a white balance circuit that adjusts the level of the primary color signal according to the white balance control signal to perform white balance control is installed, and the control means is the full screen in the first mode. A mode is selected, and a screen division mode is selected in the second mode.

Further, the video camera of the present invention receives an image signal corresponding to a picked-up image, divides the picked-up screen into a number of areas, and can output an image signal in one area over one field period, and A screen dividing unit that sequentially shifts one area capable of outputting an image signal at a cycle of one field period, and an image signal output from the screen dividing unit is integrated and an integrated value is output every one field period. Based on the integrating means and the integrated value output from the integrating means, it is determined whether or not the average of the image on the screen outputting the image signal is substantially white, and it is determined according to the integrated value when it is determined to be substantially white. A control unit that outputs a white balance control signal and a white balance circuit that adjusts the level of the primary color signal according to the white balance control signal to control the white balance are provided. An automatic white balance device is installed, and the control means issues an instruction to reduce the number of area divisions of the screen division means in the first mode and increase the number of area divisions of the screen division means in the second mode. It is characterized by

[0012]

In the present invention, high-speed white balance control is performed for a predetermined period after the recording button is pressed, and then low-speed white balance control is performed.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an image pickup system of a video camera incorporating the present invention. Lens 1 as shown in the figure
The optical image formed by is formed on the light receiving surface of the CCD 3, and the image pickup signal S is output from the CCD 3. The image pickup signal S is subjected to sample hold processing and gain adjustment in the sample and hold and AGC circuit 5, and further converted into a digital signal by the A / D converter 7, and then the luminance signal processing circuit 11 and the color separation of the signal processing circuit unit 9. Circuit 13,
It is input to the color separation circuit 15.

The luminance signal processing circuit 11 uses signal processing to
This digital brightness signal DY is created and output.
DY is an analog luminance signal by the D / A converter 17.
Converted to Y and output. The color separation circuit 13 is a signal processing unit.
The three types of primary color signals R, G, and B are created and output according to the logic.
The primary color signals R, G, B are white balance control signals R
_cont, B_contDepending on the white balance circuit 19
White balance control (gain adjustment) at
Balanced control of primary color signals R, G, B is color signal processing
The signal is processed by the circuit 21 to obtain a digital color signal DC
Become. This color signal DC is output by the D / A converter 23.
The analog color signal C is converted and output.

The color separation circuit 15 performs signal processing to perform digital processing.
Brightness signal Y and color synthesis signal C of Tal _r , C_b Output
It In the subsequent stage of the color separation circuit 15, the screen division circuit 2
5, the integrator 27 and the microcomputer 29 are connected
Has been. The microcomputer 29 is a matrix
Arithmetic unit 31, substantially white judgment unit 33, averaging unit 35, control value performance
It has a calculation unit 37 and a screen division control unit 39.

The screen division circuit 25 includes a screen division control unit 39.
When receiving a full-screen command from, the signals Y, C _r , and C _b of the whole screen are output in the 1V period, and when receiving the split-screen command, the signal Y in one divided area in the 1V period, Only C _r and C _b are output. The integrator 27 performs an integration process and integrates the brightness signal Y, and an integrated brightness value IY,
The color synthesis signals C _r and C _b are integrated to output color synthesis integration values IC _r and IC _b , respectively.

The matrix calculator 31 of the microcomputer 29 performs matrix processing to obtain integrated values IY, IC.
_The green integrated value IG, the red integrated value IR, and the blue integrated value IB are obtained from _{r 1} and IC _b, and the ratio I of the integrated value IR to the integrated value IG is calculated.
R / IG and the ratio IB / of the integrated value IB to the integrated value IG
Ask for IG.

The substantially white determination unit 33 determines the ratio IR / IG and the ratio IB.
Based on the value of / IG, it is determined whether the image of the divided area from which the signal is extracted is substantially white. This determination is performed as follows. First, in the substantially white determination unit 33, a black body radiation approximate curve CBL and an auto white balance following range A1 as shown in FIG. 2 are set. Blackbody radiation approximate curve C
BL captures an image of a "white" subject under light sources having different color temperatures, and correlates the ratio IR / IG, IB / IG of the integrated values of the signal levels of the primary color signals R, G, B in this image capture signal. Obtained by asking for a relationship. A tracking range A1 for performing an appropriate white balance is provided above and below the black body radiation approximate curve CBL, and the ratio IR / IG, I
When B / IG enters the tracking range A1, it is determined that the image of the area from which the signal is extracted is substantially white. Then, the ratio IR / I of the signal obtained from the area determined to be substantially white
Only G and IB / IG are input to the averaging unit 35.

The averaging unit 35 uses the ratio I determined to be substantially white.
R / IG, IB / IG are added and averaged, and added and averaged value AIR
/ AIG, AIB / AIG are output. Control value calculator 3
Reference numeral 7 outputs white balance control signals R _cont and B _cont that enable optimum white balance control based on the addition average values AIR / AIG and AIB / AIG. White balance adjustment is performed by the white balance circuit 19 using the white balance control signals R _cont and B _cont .

<Example of White Balance for Switching Signal Capture Pattern> Here, the operation for speeding up the control cycle and improving the follow-up property when performing the automatic white balance control in the split screen integration type will be described. First, the screen division control unit 39 of the microcomputer 29 outputs a division screen command for dividing the screen into 20 areas a1 to a20 to the screen division circuit 25 as shown in FIG. 3, and at the same time every one field period (1V period). In order of odd numbered area a
1, a3, a5, a7, a9, a11, a13, a1
Pattern 1 for extracting signals from 5, a17 and a19,
Even-numbered areas a2, a4, a6, a8, a10, a12, a14, in order for every one field period (1V period).
Pattern 2 for extracting signals from a16, a18, a20
A command for alternately repeating is output to the screen division circuit 25.

The operation at this time is shown in the block diagram of FIG. 1 and FIG.
This will be described with reference to the diagram showing the divided screens and the flowchart of FIG. When the pattern 1 is set (steps P1 and P2 in FIG. 4), the signals Y, C _r , and C that enter the area a1 in the first field period are set.
_b only, is output from the screen division circuit 25, the signal _Y, C r, the integral value IY obtained by integrating the _{C b,} IC r, IC _b
Is input from the integrator 27 to the microcomputer 29 (P3). Then, the matrix calculation unit 31 calculates the ratio IR / I from the integrated values IY, IC _r , and IC _b in the area a1.
G and IB / IG are obtained (P4), the substantially white determination unit 33 determines whether or not it is substantially white (P5 and P6), and when it is substantially white, the ratio IR / IG value and the ratio IB / IG at this time are determined. Is added to the averaging unit 35 (P7). When it is not substantially white, the addition process is not performed.

In the second field period, the same processing as described above is performed on the signal component entering the area a3 (P2 to P2).
7) Similarly, the same processing is performed for the signal components entering the odd-numbered areas a5, a7, a9, ... A15, a17, a19 one by one for each field (P2 to P7). When the processing of the area a19 is completed (P8), the arithmetic mean values AIR / AIG and AIB / AIG of the data which are determined to be substantially white in the pattern 1 and are input to the arithmetic mean unit 35 are obtained (P9). This arithmetic mean value is obtained by dividing the values of IR / IG and IB / IG added by the arithmetic mean unit 35 by the number of areas determined to be substantially white. That is, areas a1 and a
3, the ratios IR / IG and IB / IG of the areas determined to be substantially white among a5, a ... A15, a17 and a19 are averaged.

Additive average value AIR / AI in pattern 1
When G and AIB / AIG are obtained, pattern 2 is set (P10).

The control value calculator 37 calculates the arithmetic mean values AIR / AIG and AIB / AIG obtained in the pattern 1 this time, and the pattern 2 which has already been executed last time (this is the same operation as the pattern 1 as described later). The target areas are even-numbered areas a2, a4, a6 ..., A18, a20.
The average value AIR / A obtained in
The moving average of IG and AIB / AIG is calculated (P11).

The control value calculator 37 calculates white balance control signals R _cont , B for optimal white balance control based on the moving average value obtained by the averaging unit 35.
and it outputs the _{con t.} Thus, when the pattern 1 is completed, in other words, when the processing in the ten areas a1, a3, ...
White balance control is possible. Therefore, the control cycle is halved as compared with the conventional technique in which the white balance control is performed after the entire processing of the 20 areas is completed, and the speed is increased to follow a rapid color temperature change.

FIG. 5 is an explanatory diagram showing the operating state when the pattern 1 is selected.

When the pattern 2 is set (P10, P
1, P22), and only the signals Y, C _r , and C _b that enter the area a2 in the eleventh field period (the field period next to the tenth field period of the pattern 1) are output from the screen division circuit 25. Integrated values IY, IC _r , and IC _{b obtained} by integrating Y, C _r , and C _b are input from the integrator 27 to the microcomputer 29 (P23). Then, the matrix calculation unit 31 causes the integrated value I in the area a2 to be calculated.
The ratios IR / IG and IB / IG are obtained from Y, IC _r , and IC _b (P24), and the substantially white determination unit 33 determines whether or not it is substantially white (P25, P26). The value of the ratio IR / IG and the value of the ratio IB / IG are added to the averaging unit 35 (P27). When it is not substantially white, the addition process is not performed.

In the twelfth field period, the same processing as described above is performed on the signal component entering the area a4 (P22-
Similarly, the same processing is performed for the signal components entering the even-numbered areas a6, a8, a10, ... A16, a18, a20 one by one for each field (P22 to P2).
7). When the processing of the area a20 is finished (P28), the arithmetic mean values AIR / AIG, AIB / of the data which are determined to be substantially white in the pattern 2 and input to the arithmetic mean unit 35 are obtained.
AIG is calculated (P29). This arithmetic mean value is obtained by adding the values of IR / IG and IB / IG added by the arithmetic mean unit 35,
It is divided by the number of areas determined to be substantially white. That is, the ratios IR / IG, IB / I of the areas a2, a4, a6, ...
It is the average of G.

Addition average value AIR / AI in pattern 2
When G and AIB / AIG are obtained, pattern 1 is set again (P30).

The control value calculation unit 37 calculates the arithmetic mean values AIR / AIG and AIB / AIG obtained in the pattern 2 this time and the arithmetic mean value AI obtained in the pattern 1 which has been already performed previously.
Take the moving average of R / AIG and AIB / AIG (P3
1).

The control value calculator 37 calculates white balance control signals R _cont , B for optimum white balance control based on the moving average value obtained by the averaging unit 35.
and it outputs the _{con t.} Thus, the white balance control can be performed when the pattern 2 is completed, in other words, when the processing in the ten areas a2, a4, ... Therefore, the control cycle is halved as compared with the conventional technique in which the white balance control is performed after the entire processing of the 20 areas is completed, and the speed is increased to follow a rapid color temperature change.

FIG. 6 is an explanatory diagram showing an operation state when the pattern 2 is selected.

As described above, the reason why the white balance control can be performed every time the processing of each pattern is completed by dividing into the pattern 1 and the pattern 2 is that each area of the pattern 1 and each area of the pattern 2 are adjacent to each other. This is because it can be expected that similar data exists in the adjacent area, and as a result, almost accurate control can be performed even if the arithmetic processing is performed using only the data in half the area.

<Example of White Balance for Switching Screen Integral Type> Next, operation for switching between split screen integral type operation and full screen integral type operation according to the situation of the photographed image depending on the situation of the photographed image. Will be described with reference to the block diagram of FIG. 1, the flowchart of FIG. 7, and the state explanatory diagram of FIG.

At the time of start, a full-screen command is issued from the screen-division control unit 39 of the microcomputer 29 to the screen-division circuit 25 so as to perform a full-screen integration type operation, so that no screen division is performed and all areas of one screen are entered. Signal Y,
C _r and C _b are output from the screen division circuit 25 every one field period. Therefore, the integrator 27 outputs the integrated values IY, IC _r , and IC _{b for} one screen every one field period (step 41 in FIG. 7). That is, a full screen integration type operation is performed.

In the microcomputer 29, the ratios IR / IG and IB / IG are calculated by the matrix calculation unit 31, and the substantially white judgment unit 33 judges whether the average in all areas of one screen is substantially white (P42). . If it is not substantially white, the process returns to step P41, and if it is substantially white, the control value calculator 37 calculates white based on the ratios IR / IG and IB / IG obtained by calculating the signal components of all areas of one screen. The balance control signals R _cont and B _cont are calculated (P4
4) The signal is output, and white balance control is performed by the white balance circuit 19 based on the signals R _cont and B _cont (P45). A state in which the operation of performing the entire surface photometry is repeated is shown by the route in FIG. The operation of repeating the whole surface photometry is performed every one field period, is a high-speed operation, and can follow a rapid change in color temperature.

When it is determined that the average in all areas of one screen is approximately white during the full-screen photometry (P
41, P42, P43), a full screen integration type operation is performed and white balance control is performed (P44, P43).
45), and then shifts to the split-screen metering mode (P4
6, the route of FIG. 8). That is, a split screen command is issued from the screen split control unit 39, and the screen split circuit 25 splits the screen.
It is divided into 0 areas a1 to a20 (see FIG. 3). Areas a1, a2, a3, a4 ... a1 for each one field period
The signals Y, C _r , and C _b entering 8, a 19, and a 20 are individually and sequentially output. That is, in the first field period, the signals Y, C _r , and C _b entering the area a1 are output, and in the second field period, the signals Y, C _r , and C _b entering the area a2 are output.
In the same manner, the areas a3, a4, and the like are cycled every one field period.
The operation of sequentially outputting the signals entering a5, ... A18, a19, a20 is repeated.

For this reason, the integrator 27 integrates the signals in one area for each field period to obtain an integrated value IY,
It outputs IC _r and IC _b . The substantially white determination unit 33 determines whether the average of the signals entering each area is substantially white (P4
7), if it is substantially white, the ratios IR / IG, IB / I at this time
G is added and averaged by the addition and averaging unit 35 (P48, P4
9) If the color is not substantially white, the averaging is not performed. When the processing from area a1 to area a20 is completed (P5
0), the number of areas determined to be substantially white is 10 of the total number of areas.
It is determined whether it is less than or equal to% (P51). If it is not 10% or less, the ratio IR /
The total value of IG and IB / IG is divided by the number of areas determined to be substantially white, and the average value AIR / AIG and AIB / AIG are added.
Is calculated (P52), and the control value calculation unit 37 causes the addition average value AI
White balance control signals R _cont and B _cont are obtained based on R / AIG and AIB / AIG (P53). The white balance circuit 19 outputs a white balance control signal R
White balance control is performed based on _cont and B _cont (P54). The operation (P46 to P54) for repeating such a split screen integration type operation is shown by a route in FIG. In the split screen integration operation, the calculation time is long as "1 field period x number of divided areas", but white balance control is performed using only the signal components of the areas that are substantially white, so accurate white balance adjustment is performed. It can be performed.

When the number of areas determined to be substantially white when the substantially white determination from the areas a1 to a20 is finished is 10% or less of the total number of areas (P51, route in FIG. 8), white balance control is performed. Stop the operation (P5
5) Return to full-screen integration type operation (P55, route in FIG. 8).

After all, in the present embodiment, when the photographing is started or when the average of the colors of the photographed object is not substantially white, the rough and high-speed white balance control is performed by the operation of the full screen integration type, and the average of the colors of the photographed object is substantially equal. When it is white, a highly accurate white balance control is performed by a split screen integration type operation.

When the split screen integration type operation is repeated (route in FIG. 8), two capture patterns 1 and 2 are set as shown in FIGS. 5 and 6, and both patterns are alternately used. White balance control may be performed.

<Example of a video camera that performs high-speed white balance after the recording button is turned on, and then performs accurate white balance at a low speed> Next, an example in which the present invention is applied to a video camera having a power save mode 1 and FIG. 9 will be described. In a video camera equipped with a power save mode, power is supplied to the microcomputer 29 of the imaging system shown in FIG. 1 when the recording button is not pressed even when the power switch is turned on, but the other parts. Power is not supplied to the power supply, which reduces power consumption. During such a power save, the iris is closed, and the mechanical system is supplied with electric power and the rotary drum is rotating.

When the power switch is turned on
When the recording button is turned on, power is supplied to the entire imaging system.
As shown in FIG. 9, until proper exposure
After the iris opens at high speed and the correct exposure is reached, the actual recording
The drawing starts. When the actual recording starts,
White balance control must be possible immediately
Therefore, the actual recording starts after the power switch is turned on.
In the meantime (for example, 0.50 seconds)
Computer 29 is a white balance control signal_{Rc ont}，
B_contThe values of are calculated one after another at high speed (at this time
R_cont, B _contIs not output), when recording starts
From the point, the white balance control signal R_{c ont}，
_BcontIs calculated and is actually output. like this
R at each time point during period I before the start of recording_cont, B
_contSince we are seeking the value of
_cont, B_contThe value of is stable, and as a result, the recording starts.
R output immediately after the start_cont，_BcontValue of is optimal
The white balance can be adjusted.

Therefore, the microcomputer 29 sends a full screen command from the screen division control unit 39 to the screen division circuit 25 in the period I from when the recording button is pressed until the actual recording is started. Therefore, the screen division circuit 25 outputs the signals Y, C _r , and C _b of the entire screen every one field period, and the integrator 27 and the microcomputer 29 perform the full screen integration type operation, and the one screen period every field period. Then, the values of the white balance control signals R _cont and B _cont are calculated. In this way, the calculated value can be output for each one-field period, so that the calculation can be performed at high speed.

Further, the microcomputer 29 controls the screen division control unit 3 in the period II after the actual recording is started.
9 sends a split screen command to the screen split circuit 25. Therefore, the screen division circuit 25 displays the screen in 20 areas a1 to a20.
(See FIG. 3) and outputs the signals Y, C _r , and C _b which enter the areas a1 to a20 in order in one field period cycle. Then, the integrator 27 and the microcomputer 29 perform a split screen integration type operation, and a white balance control signal R capable of performing an accurate white balance for each period of "1 field period x number of divided areas (20)". _{con t, B cont} is calculated, the actual output, the white balance control is performed by the white balance circuit 19.

In the above description, the full-screen integration type operation is performed in the period I and the split-screen integration type operation is performed in the period II. However, the split-screen integration type operation is performed in both the periods I and II. The number of divided areas may be reduced (for example, 4 areas), and the number of divided areas may be increased during period II (for example, 20 areas).

Further, the length of the period I may be fixed to a fixed time after the recording start button is pressed. Further, the time to actually start recording may be determined after a certain period of time from the time when the iris becomes stable.

In any case, in period I, the
Itobalance control signal R_cont, B_contPlay the value of
In the latter half of period I, R_cont, B
_contThe value of has become stable and is output at the beginning of period II
White balance control signal R _cont, B_cont
The value of does not allow accurate white balance control.
ing.

[0050]

As described in detail with the embodiments, the present invention enables stable and accurate white balance control when the actual recording is started.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an image pickup system of a video camera incorporating the present invention.

FIG. 2 is a characteristic diagram showing a black body radiation approximation curve and an AWB tracking range.

FIG. 3 is an explanatory diagram showing divided areas of a screen.

FIG. 4 is a flowchart showing an area data high-speed fetch operation.

FIG. 5 is an explanatory diagram showing an outline of operation in a capture pattern 1.

FIG. 6 is an explanatory diagram showing an outline of operations in a capture pattern 2.

FIG. 7 is a flowchart showing an operation of switching between full-area photometry / screen division photometry.

FIG. 8 is an explanatory diagram showing an example of white balance for switching the screen integration type.

FIG. 9 is a characteristic diagram showing operating characteristics of a video camera that performs high-speed white balance after the recording button is pressed and then performs low-speed white balance.

[Description of Reference Signs] 1 lens 3 CCD 5 sample and hold and AGC circuit 7 A / D converter 9 signal processing circuit section 11 luminance signal processing circuit 13 color separation circuit 15 color separation circuit 17 D / A converter 19 white balance circuit 21 Color signal processing circuit 23 D / A converter 25 Screen division circuit 27 Integrator 29 Microcomputer 31 Matrix calculation section 33 Substantial white determination section 35 Addition averaging section 37 Control value calculation section a1 to a20 Area S Imaging signal DY, Y Luminance signal R, G, B primary color signals R _cont , B _cont white balance control signal DC, C color signals C _r , C _b color composite signal IY luminance integrated value IC _r , IC _b color composite integrated value IR / IG, IB / IG ratio AIR / AIG, AIB / AIG arithmetic mean value

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C065 AA01 BB02 CC01 DD02                 5C066 AA01 CA08 CA23 EA15 GA05                       KE05 KE17 KE24 KM02

Claims (6)

[Claims] 1. When the recording button of the video camera is turned on, the automatic white balance control is performed in the first mode for a predetermined period after the recording button is turned on, and thereafter the automatic white balance control is performed in the second mode. Characteristic video camera. 2. The video camera according to claim 1, wherein the predetermined period is a preset fixed time. 3. The video camera according to claim 2, wherein the predetermined period is a time period from when a recording button is pressed to when actual recording is started. 4. The video camera according to claim 3, wherein actual recording starts on condition that the iris is stable. 5. The video camera according to claim 1, wherein an image signal corresponding to a picked-up image is input, and the picked-up screen is divided into a number of areas and an image signal which enters one area is output over one field period. In addition, there are a screen division mode in which one area capable of outputting an image signal is sequentially shifted at a cycle of one field period, and a full screen mode in which all image signals in one screen are output in one field period. The screen dividing means has, an integrating means that integrates the image signal output from the screen dividing means and outputs an integrated value for each field period, and outputs an image signal based on the integrated value output from the integrating means. A white balance control signal for determining whether the average of the images on the screen is substantially white, and outputting a white balance control signal according to the integrated value when it is determined to be substantially white; An auto white balance device equipped with a white balance circuit for performing white balance control by adjusting the level of the primary color signal according to the lance control signal is mounted, and the control means is in full screen mode in the first mode. , And a video camera characterized by selecting a screen division mode in the second mode. 6. The video camera according to claim 1, wherein an image signal corresponding to a picked-up image is input, and the picked-up screen is divided into a number of areas and an image signal to be put into one area can be output over one field period. In addition, a screen dividing unit that sequentially shifts one area capable of outputting an image signal at a cycle of one field period, and an image signal output from the screen dividing unit is integrated to obtain an integrated value for each one field period. Based on the integrating means to output and the integrated value output from the integrating means, it is judged whether the average of the image on the screen outputting the image signal becomes substantially white. A white balance control circuit that outputs a corresponding white balance control signal and a white balance circuit that adjusts the level of the primary color signal according to the white balance control signal to perform white balance control. , And an automatic white balance device having a screen dividing means for reducing the number of area divisions of the screen dividing means in the first mode, and increasing the number of area divisions of the screen dividing means in the second mode. Video camera characterized by commanding to.