JPH05211655A - Video camera - Google Patents

Abstract

PURPOSE:To photograph with a color tone near to human visual sense even during an overseas tone by providing a means which corrects the white balance setting position of a white balance adjusting circuit closer to the human visual sense. CONSTITUTION:A location selection circuit 27 by which the country location in the world can be set, and a time clock circuit 20 which generates the time information for the selected location by a control signal outputted from the location selection circuit 27 are equipped with a white balance setting position correction circuit 21 which corrects the setting position of white balance of the white balance adjusting circuit, i.e., color temperature corresponding to the time information obtained from the time clock circuit 20. The location (abroad) is selected and set, and correction data for the color temperature of photographed natural light set at every selected location can be obtained, and the white balance setting position of the white balance adjusting circuit 16 can be corrected so as to approach the visual sense of the photographed natural light based on the correction data.

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 more particularly to a white balance adjusting device for a video camera.

[0002]

2. Description of the Related Art Examples of this type are, for example,
No. 16011 can be mentioned. FIG. 5 is a block circuit diagram showing a white balance adjusting circuit of a conventional video camera. In the figure, 1 is a lens, 2 is an image sensor,
3 is a color separation circuit, 4 is an R channel gain control circuit, 5
Is a B channel gain control circuit, 6 is a process circuit, 7
Is a matrix circuit, 8 is an encoder circuit, 9 is an output terminal, 11 is an R sensor (a photoelectric conversion element having a sensitivity mainly in red), 12 is a G sensor (a photoelectric conversion element having a sensitivity mainly in green), and 13 is B sensor (mainly photoelectric conversion element having sensitivity to blue), 14 and 15 are division circuits, and the gain control circuits 4 and 5 and the division circuits 14 and 15 form a white balance adjustment circuit 16.

Next, the operation will be described. The incident light image from the lens 1 is photoelectrically converted by the image pickup device 2 and color-separated by the color separation circuit 3 into three color signals of R, G, and B. The gain control circuit 4 controls the gain of the R signal, and the gain control circuit 5 controls the gain of the B signal to adjust the white balance of the captured image. On the other hand, the R sensor 11, G sensor 12, and B sensor 13 generate output signals R _S , G _S , and B _S proportional to the R component, G component, and B component of the incident light. The divider circuit 14 calculates the ratio G _S / R of the G component and the R component that does not depend on the amount of incident light.
Outputs _S (= V _R), the division circuit 15 outputs the ratio B _S / G _S of the B component and the G component (= V _B). Gain control circuit 4
Has a control characteristic such that its gain increases as the control voltage V _R increases, and the gain control circuit 5 decreases its gain as the control voltage V _B increases.
In the case of a light source having a low color temperature, that is, a light source having a large number of R components with respect to a G component and a small amount of B components, the values of the control voltages V _R and V _B are lower than those when the color temperature is high. Therefore,
When the color temperature of the light source is low, the gain of the R channel gain control circuit 4 is small, and the gain of the B channel gain control circuit 5 is large.

On the other hand, in the case of a light source having a high color temperature, that is, a light source having a small amount of R component and a large amount of B component with respect to the G component, the gain of the R channel gain control circuit 4 becomes large, and the B channel gain control circuit. The gain of 5 becomes smaller. In this way, the gain of the R channel gain control circuit 4 and the gain of the B channel gain control circuit 5 are automatically controlled with respect to changes in the R, G, and B components included in the light source, that is, the color temperature. By doing so, the white balance is adjusted.

[0005]

Since the conventional white balance device for a video camera is constructed as described above, it is always adjusted to a constant white balance even if the color temperature of the light source changes. Therefore, for example, a white subject is clearly imaged to the human eye such as a sunset, and the subject is imaged white even when the subject looks reddish. In addition, there is a problem that when a video camera is used in a place (foreign country) where there is a time difference and the time of sunshine or sunset is different, a similar phenomenon occurs and an unnatural image is obtained.

The present invention has been made in order to solve the above-mentioned problems, and of course, not only when the color temperature of the light source changes, but also when there is a time difference, and when the time of sunshine or sunset is different (foreign country). An object of the present invention is to obtain a white balance device for a video camera, which is capable of performing white balance adjustment that provides a more natural captured image that is close to the human visual sense even when shooting.

[0007]

A white balance device according to the present invention corresponds to a means for selecting and setting a place (foreign country) and a color temperature of natural light at the time of photographing set for each of the selected places. It is provided with means for obtaining correction data, and means for correcting the white balance setting position of the white balance adjusting means based on the correction data so that the white balance setting position becomes closer to the visual sense due to natural light at the time of shooting.

[0008]

The means for setting the place (foreign country) in the present invention can select the place of each country from the outside from the outside. When the place is selected and set, the control signal for adjusting to the time of the place and the place The means for outputting the select signal necessary for selecting the correction data table corresponding to that time and obtaining the correction data is based on the color temperature of the natural light at that location stored in the correction data table selected by the select signal. The means for outputting the corresponding correction data and correcting the white balance setting position is such that the white balance setting position of the white balance adjusting means approaches the color temperature of natural light at the time of shooting based on the correction data (for example, at the time of sunset (sunset)). , And shift the white balance toward red) to change the white balance setting.

[0009]

EXAMPLES Example 1. FIG. 1 is a block circuit diagram showing the configuration of the present invention. In the figure, 27 is a place selection circuit capable of setting places in each country of the world, 20 is a clock circuit 21 for generating time information of a place selected by a control signal output from the place selection circuit 27, and 21 is a clock circuit. 20
The white balance adjustment circuit 16 according to the time information obtained from
The white balance setting position correction circuit for correcting the white balance setting position, that is, the color temperature.

FIG. 2 is a block circuit diagram of an embodiment in which the place selection circuit 27 is concretely shown. 31 is an information storage unit for storing information such as places in each country of the world and their time differences (reference is Japan), and 30. Is a place selection counter that counts the contents in the information storage unit 31 when the place is selected from the outside,
Reference numeral 32 is a character generator that outputs the information in the information storage unit 31 as a character (country name), 33 is a display output terminal for displaying the output of the character generator 32, and 28
Is a selection instruction terminal for causing the location selection counter 30 to count the contents of the information storage unit 31, 29 is a selection determination terminal for stopping the location selection counter 30 when determining the location, and 34 is an information storage unit 31 The current time (hour / minute) of the place selected by the selection determining terminal 29 is measured by the current time from the time counting circuit 20 output by the control signal and the time difference information of the selected place obtained from the information storage unit 31. It is a timer circuit that outputs information to be generated from the time circuit 20.

In FIG. 3, the white balance adjusting circuit 16 has the same configuration as that of the conventional example shown in FIG. 5, and the white balance setting position correcting circuit 21 (including the interface with the place selecting circuit 27).
22 is a block circuit diagram of an embodiment in which the correction value table for outputting the data for correcting the setting position of the white balance by the output information of the time counting circuit 20 and the selection signal from the place selection circuit 27, 23, 24 is a D / A converter that converts the correction data output from the correction value table into an analog signal; 25 is the output C _R of the D / A converter 23;
An adder for adding the output V _R of the division circuit 14, also 2
Reference numeral 6 denotes an adder for adding the output C _B of the D / A converter 24 and the output V _B of the division circuit 15. The output V _RT of the adder 25 is the gain control circuit 4 and the output V _BT of the adder 5 is the gain. Each is input to the control circuit 5 as a gain control signal.

Next, the operation will be described. First, I will explain the current location as Japan. The photographer first selects the place selection circuit 2
The selection instruction terminal 28 of 7 operates the place selection counter 30 to look for Japan while looking at the display output 33, and sets it at the selection determination terminal 29. At that time, the information storage unit 31
From Japan, that is, the control signal for setting the time, the time difference information to the timer circuit 34 (0 in this case because the reference is Japan) and the select signal to the correction value table (to select the Japanese correction data table). Is output. To set the time, the current time is input from the time counting circuit 20 to the timer circuit 34 by the control signal from the information storage unit 31 and the time difference information from the information storage unit 31 is calculated (for example, 6: 30 ±
0 = 6: 30), and it is generated from the time counting circuit 20 as time information.

The correction value table 22 outputs white balance setting position correction data in accordance with time information input from the time counting circuit 20 and a select signal from the information storage unit 31,
The correction data is converted into analog correction signals C _R and C _B by the D / A converters 23 and 24. As shown in FIG. 4A, the correction signals C _R and C _B change with time such that the morning and evening levels are high and the daytime levels are low. The adders 25 and 26 add the correction signals C _R ,
C _B is added to the control voltages V _R and V _B (outputs of the division circuits 14 and 15), respectively. The control voltages V _RT and V _BT to which the correction signals C _R and C _B are added are input to the gain control circuits 4 and 5 to change their gains. The gain control circuit 4 increases its gain as the control voltage V _RT increases, and the gain control circuit 5 decreases its gain as the control voltage V _BT increases. Therefore, in the morning and evening, the control voltage V _RT , V _BT becomes larger than before correction, the gain of the R channel gain control circuit 4 becomes larger, and becomes smaller than the gain of the B channel gain control circuit 5, so that the white balance is set to a position slightly shifted to the red side. .. On the contrary, the daytime control voltages V _RT and V _BT become slightly smaller than V _R and V _B , and the white balance is set to a position slightly shifted to the blue side.

Next, the operation when using the video camera in a foreign country (for example, Paris) will be described. This time, the photographer uses the selection instruction terminal 28 of the location selection circuit 27 to count the location selection counter 30 and looks for Paris while looking at the display output 33, and sets it in the selection determination terminal 29. At that time, information in Paris from the information storage unit 31, that is, a control signal for setting the time and time difference information to the timer circuit 34 (in this case, it is -8 hours in Japan) and correction to select the correction data table in Paris Output a select signal to the value table. To set the time, the current time (Japan time) is input from the time counting circuit 20 to the timer circuit 34 by the control signal from the information storage unit 31 and calculated with the time difference information from the information storage unit 31 (for example, PM 6:30). -8 hours = 10: 30 am), and the time information is generated from the time counting circuit 20.

The correction value table 22 selects a correction data table for Paris based on the time information input from the time counting circuit 20 and a select signal from the information storage unit 31, and outputs the white balance setting position correction data corresponding thereto. The correction data is converted into analog correction signals C _R and C _B by the D / A converters 23 and 24. This correction signal C _R , C
_{Since B} has a different longitude as a place, it changes according to time such that the morning and evening levels are high and the daytime levels are low, as shown in FIG. 4A, as in Japan. (Locations with different latitudes have almost no time difference, but sunshine and sunset times are different, so the level changes as shown in FIG. 4B). Subsequent processing is the same as above with the adders 25 and 26.
Then, the correction signals C _R and C _B are added to the control voltages V _R and V _B (outputs of the dividing circuits 14 and 15), respectively, and the control voltage V _RT and the addition of the correction signals C _R and C _B are obtained. V _BT is input to the gain control circuits 4 and 5 to change its gain.
The gain control circuit 4 increases its gain as the control voltage V _RT increases, and the gain control circuit 5 controls the control voltage V _RT.
Since the gain decreases as _BT increases,
In the morning and evening, the control voltages V _RT and V _BT become larger than before correction (however, the time is short in the place corresponding to (b) of FIG. 4), and the gain of the R channel gain control circuit 4 becomes larger, The gain is smaller than the gain of the B channel gain control circuit 5, and the white balance is set to a position slightly shifted to the red side.

On the contrary, the control voltages V _RT and V _BT during the day are V _R and
It becomes slightly smaller than V _B (however, the time is long at the location corresponding to the correction data in FIG. 4B), and the white balance is set to a position slightly shifted to the blue side. Also,
When the camera is used under photographing conditions (good weather, indoors, etc.) that are significantly different from the data in the correction value table 22, the selection determination terminal 29 is switched and the operation of the place selection circuit 27 is stopped so that only the white balance adjustment circuit 16 is operated. Use to adjust the white balance. In this way, the white balance setting position is corrected according to the place and the time, so that the color tone of the image captured in any country in the world becomes an image having a color tone close to that of the visual sense.

Embodiment 2. In the above embodiment, the correction data of the correction value table 22 is set according to the time of day, but the correction data may be set according to the season of the year.

[0018]

As described above, according to the present invention, the white balance setting position of the white balance adjusting circuit approaches the human visual sense so as to follow the change in the color temperature of natural light based on the place and time at the time of photographing. Since the correction means is provided as described above, there is an effect that a video camera capable of shooting with a color tone close to that of a human being can be obtained even when traveling abroad.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a configuration of a white balance device according to an embodiment of the present invention.

FIG. 2 is a block circuit diagram showing a configuration of a place selection circuit according to an embodiment of the present invention.

FIG. 3 is a block circuit diagram showing a specific configuration of a white balance device according to an embodiment of the present invention.

FIG. 4 is a diagram showing changes in correction data with respect to time according to an embodiment of the present invention.

FIG. 5 is a block circuit diagram showing a conventional white balance device.

[Explanation of symbols]

 16 White balance adjustment circuit 20 Clock time circuit 21 White balance setting position correction circuit 27 Place selection circuit

Claims (1)

[Claims] 1. A white balance adjusting means, a means for obtaining correction data corresponding to a color temperature of natural light at the time of photographing, and a white balance setting position of the white balance adjusting means for visualizing the white balance setting position by the natural light at the time of photographing. A video camera comprising: a means for correcting so as to approximate the feeling; and a selecting means for selecting and setting the correction data obtained by the means for obtaining the correction data according to a place (a foreign country).