JP2001095008A - Image-pickup unit and white balance adjusting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-pickup unit and a white balance adjusting method capable of adjusting white balance with high accuracy and providing a more natural photographed image. SOLUTION: A digital camera 10 is provided with a microcomputer 12. A place information acquiring device 39, photographed date and time acquiring device 40 and a meteorological information acquiring device 42 are connected with the microcomputer 12. The microcomputer 12 determines corrected values of primary color signals R, G, B for adjusting the white balance by using acquired place information, photographed date and time and meteorological information and outputs the values to white balance adjusting amplifiers 36R, 36G and 36B via a D/A converter 44, when the image is photographed at time such as the daytime when influence of the sunlight remains. In the white balance adjusting amplifiers 36R, 36G and 36B, the primary color signals R, G, B of an image signal picked up by a CCD 32 to be outputted from a signal processing circuit 34 are corrected by the corrected values and outputted to an encoding circuit 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus such as an electronic still camera and a white balance adjusting method.

[0002]

2. Description of the Related Art Conventionally, in an imaging apparatus such as a camera, white balance is adjusted so that a white subject is reproduced white. Conventionally, this white balance adjustment is performed by using an RG output from the image sensor during photometry immediately before shooting.
The B signal is monitored, and the level of the RGB signal is controlled so as to be adjusted to a constant white balance.

[0003] In such a case, even when an originally white subject appears reddish, such as when photographing at sunset, the subject is reproduced white, resulting in an unnatural photographed image. Further, for example, when photographing is performed in a foreign country or the like where there is a time difference, the sunshine time and the sunset time are different from those in Japan.

[0004] In addition, there is another problem that the color temperature of light illuminating the subject is different even in places where the latitude, longitude and altitude are different, which results in an unnatural photographed image.

In order to solve this problem, there has been proposed a technique capable of obtaining a more natural photographed image by adjusting a white balance using correction data corresponding to a photographing place and a time difference (Japanese Patent Application Laid-Open No. Hei 5 (1993) -520). -21655).

[0006]

However, in the above prior art, since the weather at the time of photographing is not taken into consideration, a constant white balance adjustment is possible regardless of the color temperature of the illumination light even when it is sunny or cloudy. And it is difficult to obtain a natural photographed image without being affected by the weather or the like.
Also, the white balance adjustment is affected by the color of the subject. For example, even when the image is captured under illumination having the same color temperature, the color of the entire image is shifted or the color is lost due to the change in the color of the subject. Feria sometimes happened.

In order to solve this problem, there is a technique of measuring the color temperature of illumination at the time of photographing using a color temperature sensor and controlling the level of an RGB signal in accordance with the measurement result. When the directivity is low, color fear may also occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an imaging apparatus and a white balance adjustment method capable of accurately adjusting white balance and obtaining a more natural photographed image. Is the purpose.

[0009]

According to a first aspect of the present invention, there is provided an image pickup apparatus comprising: an input unit for inputting at least weather information; and a white balance adjustment of a photographed image based on the weather information. And white balance adjusting means for performing the following.

The input means inputs the weather at the shooting location, for example, weather information such as sunny or cloudy. The weather information may be input by, for example, a user performing a predetermined operation using an operation button, or provided from the information center by connecting to the information center using a communication device such as a mobile phone. Weather information to be obtained may be acquired and input.

The white balance adjusting means adjusts the white balance of the photographed image based on the weather information input by the input means. For example, a captured image is converted to a primary color signal R
(Red), G (Green), and B (Blue) are separated into color components, which are corrected by experiments and the like so that the white balance becomes appropriate according to the weather such as sunny or cloudy. Adjust the white balance by correcting the value. As a result, the white balance can be adjusted optimally according to the weather, and it is possible to prevent the occurrence of color fear.

According to a second aspect of the present invention, in the image pickup apparatus, at least one of a photographing date and time, photographing location information, and map information is inputted from the input means, and the white balance adjusting means comprises:
White balance adjustment is performed based on the weather information, the shooting date and time, the shooting location information, and the map information.

From the input means, at least one of shooting date and time, shooting location information such as location information of the shooting location, and map information such as terrain is input. The user may manually input these pieces of information. For example, the shooting date and time may be input from a clock that can also acquire the date. The shooting location information may be input from a known GPS device that is used for car navigation or the like and can detect the current position. Thereby, the position of the shooting location can be specified by, for example, latitude, longitude, and altitude. It should be noted that the shooting location may be specified by a prefecture, a city, a municipality, an area mesh code, or the like. As the map information, map information such as terrain corresponding to the position of the shooting location may be input from map data stored in a storage medium such as a CD-ROM. As a result, it is possible to specify the terrain of the shooting location, for example, a mountain or the sea.

The white balance adjusting means performs white balance adjustment in consideration of weather information, shooting date and time, shooting location information, and map information. For example, an optimal correction value is determined in advance for each of weather information (for example, sunny, cloudy, etc.), shooting date and time (for example, season, time zone, etc.), shooting location (for example, Japan, United States, etc.), and map information (sea and mountains). deep. Then, a correction value corresponding to the input weather information, shooting date and time, shooting location, and map information is selected from these, and the white balance of the shot image is adjusted using the correction values. As described above, since the white balance adjustment is performed in consideration of the information such as the shooting date and time, the shooting location, and the terrain, in addition to the weather information, it is possible to perform the accurate white balance adjustment.

According to a third aspect of the present invention, there is provided a white balance adjusting method, wherein weather information is input and white balance adjustment of a photographed image is performed based on the input weather information. It can be performed by the configuration described.

According to a fourth aspect of the present invention, there is provided a white balance adjustment method, wherein at least one of a shooting date and time, shooting location information, and map information is inputted, and the weather information, the shooting date and time,
A white balance adjustment is performed based on the shooting location information and the map information. For example, the white balance adjustment can be performed by the configuration described in the second aspect.

[0017]

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

FIG. 1 shows a digital camera 10 as an image pickup device.

The digital camera 10 has a microcomputer 12. The microcomputer 12
It is configured to include a CPU 14, a ROM 16, a RAM 18, and an input / output port (I / O) 20, and each is connected by a bus 22 so that data and commands can be transmitted and received.

A drive circuit 24 is connected to the microcomputer 12. To the drive circuit 24, a lens drive motor 26, a strobe 28, a shutter / aperture 30, and a CCD 32 are connected.

The microcomputer 12 determines an auto-focus (AF) control value based on the distance from the subject measured by a distance measuring unit (not shown), and
Output to 4. The drive circuit 24 drives the lens drive motor 26 based on the AF control value, and automatically performs focus adjustment.

In the microcomputer 12, an exposure control value, for example, an aperture value (aperture opening amount), a shutter speed, and whether or not to emit light by a strobe 28 based on a photometric value measured by a photometric unit (not shown). And outputs it to the drive circuit 24. Then, when a shutter button (not shown) is pressed, the drive circuit 24 drives the shutter / aperture 30, the CCD 32, and the strobe 28 based on the exposure control value, and shoots a subject image transmitted through the lens. If you press the shutter button halfway,
Preliminary photographing is performed to obtain information necessary for actual photographing, for example, information necessary for white balance adjustment described later and information necessary for AF control.

The CCD 32 accumulates charges corresponding to the amount of incident light in accordance with the exposure control value. The accumulated charges, that is, the image signals, are output to the signal processing unit 34. The signal processing circuit 34 processes the image signal output from the CCD 32 to generate a luminance signal Y, primary color signals R, G, and B.
Generate Each of the generated primary color signals R, G, B is
The output is output to white balance adjustment amplifiers 36R, 36G, and 36B for adjusting the white balance of the captured image.

The signal processing circuit 34 generates a luminance signal Y,
The color difference signals RY and BY are generated from the primary color signals R, G and B, and the respective integrated average values are generated. The integrated average value of the generated color difference signals RY and BY is calculated by the A / D converter 38.
Is output to the microcomputer 12 after A / D conversion. For example, in the case of shooting at night, the microcomputer 12 uses the integrated average value of the color difference signals RY and BY to correct the primary color signals R, G and B in order to perform a known white balance adjustment. To determine. In this case, the white balance adjustment is a so-called internal photometry method in which the color temperature is indirectly detected and the white balance is adjusted, and when a predetermined range of the photographed image is averaged when the white balance is matched, an achromatic color is obtained. This is an adjustment method based on the knowledge that That is, the reference value of the integrated average value of the color difference signals RY and BY is stored in the ROM 16 in advance, and the
U12 is a color difference signal R output from the signal processing circuit 32.
The correction values of the primary color signals R, G, and B are determined so that the integrated average values of -Y and BY match this reference value.

The microcomputer 12 is connected to a location information acquisition device 39, a shooting date / time acquisition device 40, a weather information acquisition device 42, and a map information acquisition device 43. The place information acquisition device 39 acquires information (for example, latitude / longitude, altitude) of the photographing place, that is, the position of the digital camera 10, and outputs the acquired information to the microcomputer 12.
For example, a GPS device used for car navigation or the like can be adopted as the shooting location information acquisition device 39. The photographing location information may be information such as a prefecture, a city, a municipality, a regional mesh code, or the like, in addition to the latitude / longitude and the altitude.
The photographing date and time acquiring device 40 outputs the photographing date and time to the microcomputer 12.

The weather information acquisition device 42 acquires weather information such as the weather at the shooting location and outputs it to the digital camera 10. The weather information acquisition device 42 can employ an input device such as an operation button, for example, and the user can input weather information such as sunny or cloudy by performing a predetermined operation with the input device. The input data is R
Stored in AM18. Alternatively, a mobile phone may be used as the weather information acquisition device 42, and the weather information may be obtained by wirelessly connecting the digital camera 10 to an information center or the like that transmits the weather information using the mobile phone.

The map information obtaining device 43 stores, for example, map information corresponding to the shooting location obtained by the shooting location information obtaining device 39, such as terrain information such as mountains and seas, for example, into a CD-R.
It is obtained from map data stored in a storage medium such as an OM and output to the digital camera 10.

When photographing at a time when the influence of sunlight remains, for example, in the daytime, the microcomputer 12 uses the acquired location information, photographing date and time, weather information, and map information to perform primary color adjustment for white balance adjustment. Signals R, G, B
Is determined.

The determined correction value is converted into an analog signal by the D / A converter 44 and output to the white balance adjustment amplifiers 36R, 36G, 36B. The white balance adjustment amplifiers 36R, 36G, 36B correct the primary color signals R, G, B output from the signal processing circuit 34 with the correction values output from the microcomputer 12, and correct the corrected primary color signals R ', G', B ′ encoding circuit 4
Output to 6.

The encoding circuit 46 encodes the corrected primary color signals R ', G', B 'into a predetermined format to generate image data, and outputs the image data to the memory card drive 48. At this time, the image data may be compressed (for example, JPEG encoded) and output to the memory card drive 50 as necessary. Memory card drive 48
Writes the input image data into a memory card 50 such as a smart media.

The ROM of the microcomputer 12
16 stores in advance a control routine to be described later and various table data to be described later.

Next, as an operation of the present embodiment, the CPU
The control routine executed in 14 will be described with reference to the flowchart shown in FIG.

When a power supply (not shown) of the digital camera 10 is turned on, a control routine shown in FIG. 2 is executed.

In step 100 shown in FIG. 2, it is determined whether or not a shutter button (not shown) is half-pressed.
If the shutter button has not been half-pressed, the operation is not in the shooting operation, and the process returns.

When the shutter button is half-pressed,
Since the photographing operation has been started, preliminary photographing is performed, and date and time information (for example, year, month, day, hour and minute) is acquired from the photographing date and time acquisition device 40 in step 102. At this time, the CCD 32
To the signal processing circuit 34, the signal processing circuit 34 generates the color difference signals RY and BY and generates the respective integrated average values. And the next step 10
In step 4, the location information acquisition device 39 acquires location information (for example, latitude / longitude, altitude) of the shooting location. In the next step 105, the map information acquisition device 43 acquires map information (topography, for example, whether it is the sea or the mountain) corresponding to the shooting location.

In the next step 106, step 10
It is determined whether the present time is daytime or nighttime from the date and time information and the location information acquired in 2,104. This is done by referring to table data stored in the ROM 16 as shown in, for example, Table 1 below, and obtaining the date in the spring (for example, 3-5
Month), summer (for example, from June to August), autumn (from September to November), or winter (from December to February), and furthermore, the obtained time is a date corresponding to the determined season. If it is after the departure time and before the sunset time, it is daytime, otherwise it is nighttime.

[0037]

[Table 1]

If it is daytime, step 1
In step 108, the weather information, such as clear or cloudy, set by the user is read from the RAM 18. In the next step 110, a correction value set corresponding to the acquired location information, map information (terrain), and weather information (weather) is selected with reference to table data as shown in Table 2 below.

[0039]

[Table 2]

On the other hand, if it was nighttime instead of daytime,
In step 106, the result is negative, and in step 112, the integrated average value of the color difference signals RY and BY of the photographed image of the preliminary photographing is fetched. Then, in the next step 114, a correction value is calculated. That is, the integrated average value of the captured color difference signals RY and BY is stored in the ROM 16 in the color difference signal RY.
The correction values of the primary color signals R, G, B are calculated so as to match the reference values of the integrated average values of Y, BY.

Then, in step 116, the correction value set is output to the D / A converter 44. The D / A converter 44 converts the correction values of R, G, and B into analog signals, and converts them into white balance adjustment amplifiers 36R, 36G, 36.
The respective correction values are output to B.

White balance adjustment amplifiers 36R, 36
In G and 36B, the primary color signals R, G and B output from the signal processing circuit 34 are respectively corrected by the input correction values to generate primary color signals R ', G' and B ', and each of the encoding circuits Output to 46.

In the encoding circuit 46, the primary color signals R ',
G ′ and B ′ are encoded into a predetermined format to generate image data and output to the memory card drive 48. The memory card drive 48 writes the input image data to the memory card 50.

As described above, in the case of daytime photographing, there is the influence of sunlight, so that white balance adjustment is performed using correction values according to date and time, place, terrain, and weather. This makes it possible to appropriately perform white balance adjustment even for a captured image in which color fear may occur with normal white balance adjustment, such as a blue sea background. Further, the white balance can be appropriately adjusted without being affected by the weather or the like, and the occurrence of color fear can be prevented.

In the case of daytime photographing, a correction value is calculated from the color difference signals RY and BY as in the conventional correction method, that is, the processing in steps 112 and 114, and the correction value and the table data are used. The final correction value may be calculated by performing weighting calculation on the selected correction value set using, for example, a membership function or the like.

Further, for each destination of the digital camera 10,
The ROM 16 may store an optimal set of correction values so as to achieve color reproduction that the user of the destination has a tendency to like. Thus, for example, even if the skin colors of the people of each country are different or the preference of color reproduction is different, it is possible to perform the optimal white balance adjustment in each case.

Further, the azimuth of the subject is detected by using a azimuth magnet or the like, and it is determined from the azimuth and time whether or not the subject is backlit. If it is determined that the subject is backlit, the strobe 28 is automatically emitted. Good.

[0048]

As described above, according to the first aspect of the present invention, the white balance can be optimally adjusted according to the weather, and the occurrence of color feria can be prevented. Having.

According to the second aspect of the invention, there is an effect that the white balance can be adjusted with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital camera.

FIG. 2 is a flowchart illustrating a flow of a control routine executed by a CPU.

[Explanation of symbols]

 Reference Signs List 10 digital camera 12 microcomputer 14 CPU 16 ROM 18 RAM 20 I / O 22 bus 24 drive circuit 26 lens drive motor 28 strobe 30 shutter / aperture 32 CCD 34 signal processing circuit 36 white balance adjustment amplifier 38 A / D converter 39 place Information acquisition device 40 Date and time acquisition device 42 Weather information acquisition device 43 Map information acquisition device 44 D / A converter 46 Encoding circuit 48 Memory card drive 50 Memory card

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C065 AA03 BB02 CC01 DD01 GG17 GG18 GG24 GG27 GG49 5C066 AA01 AA15 BA01 CA13 EA15 GA01 GA32 GB01 HA03 KA12 KE05 KM02 LA02

Claims (4)

[Claims] An image pickup apparatus comprising: an input unit for inputting at least weather information; and a white balance adjusting unit for adjusting a white balance of a captured image based on the weather information. 2. The apparatus according to claim 1, wherein at least one of shooting date and time, shooting location information, and map information is input from said input means, and said white balance adjusting means outputs said weather information, said shooting date and time, said shooting location information, and said map information. 2. The image pickup apparatus according to claim 1, wherein the white balance adjustment is performed based on: 3. A white balance adjusting method for inputting at least weather information and adjusting a white balance of a captured image based on the input weather information. 4. Inputting at least one of shooting date and time, shooting location information, and map information, and performing white balance adjustment based on the weather information, the shooting date and time, the shooting location information, and the map information. 4. The white balance adjustment method according to claim 3, wherein: