JP2003264850A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera capable of properly and automatically adjusting white balance even when a photographing scene is possibly misjudged as an indoor scene although the photographing scene is actually an outdoor scene such as a dark forest or grove. <P>SOLUTION: Even when an outdoor/indoor discrimination circuit 70 discriminates that a photographing scene is an indoor scene, if a color temperature discrimination circuit 60 discriminates that a color temperature of an object has an intermediate color temperature (around 4000°C) between a luminescent color of a white fluorescent light and a green color of a plant, a green discrimination circuit 40 further discriminates whether or not the hue of the object is the green color of plant on the basis of a distribution of hue data on the R/G-B/G coordinates, when the discrimination indicates that the hue of object indicates the green of plant, a white balance deviation correction circuit 30 weakens a degree of white balance adjustment more than a degree of white balance adjustment for indoor photographing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera having a function of automatically adjusting white balance of a photographed image.

[0002]

2. Description of the Related Art Conventionally, in a digital camera having a function of discriminating whether a photographing scene is an outdoor scene or an indoor scene, the photographing scene is discriminated based on the hue (RGB information) of a subject, The white balance was automatically adjusted according to the determination result.

However, if the photographic scene is discriminated based only on the hue of the photographic subject, the photographic scene of the photographic scene is not uniform when the color temperature distribution of the photographic subject is non-uniform or when the photographic subject is an object of a single color or a similar color. Misjudgment was likely to occur, and white balance was often adjusted incorrectly. As a result, color ferria was generated due to the white balance shift.

Therefore, in the invention disclosed in Japanese Patent Application Laid-Open No. 2000-224608, it is determined whether the shooting scene is an outdoor scene or an indoor scene based on the hue and lightness of the subject, thereby performing shooting. It is designed to prevent misidentification of scenes and white balance shift.

[0005]

However, Japanese Patent Laid-Open No. 2000-2000
In the invention described in Japanese Patent Laid-Open No. 224608, the shooting scene can be accurately determined in the case of shooting in a relatively bright place, but the shooting scene may be erroneously determined in the case of shooting in a dark place. is there. For example, when shooting is performed against a background of green vegetation in a dark forest or forest where outside light does not enter much, it is erroneously determined as an indoor shooting scene even though it is an outdoor shooting scene. Such an erroneous determination of the shooting scene occurs because the color temperature (lightness, hue) of the emission color of the white fluorescent lamp used for indoor lighting is close to the green of plants such as leaves of plants and trees.

As a result, the white balance adjustment suitable for indoor photography is performed even though it is outdoor photography. This means adjusting the white balance of green leaves to gray. When a person is photographed against a green plant background with the white balance deviated in this way, the color of the green plant becomes a shade of gray, and the flesh tone becomes a color of magenta. It gets very bad.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to be an indoor scene, such as in a dark forest or a forest, although the shooting scene is actually an outdoor scene. It is an object of the present invention to provide a digital camera capable of appropriately and automatically adjusting white balance even in the case where there is a risk of misjudgment.

[0008]

According to the present invention, there is provided a lightness detecting means for detecting lightness of an object, a hue detecting means for dividing an image of the object into a plurality of areas to detect a hue of each area, and the lightness. Outdoor / indoor discrimination means for discriminating whether the shooting scene is an outdoor scene or an indoor scene based on the lightness data obtained by the detection means and the hue data of each area obtained by the hue detection means, When the outdoor scene is determined to be an indoor scene,
The color temperature determining means for determining the color temperature of the subject based on the lightness data and the hue data, and each area when the color temperature determining means determines the color temperature of the emission color of the white fluorescent lamp. According to the distribution of the hue data on the R / G-B / G coordinates, a green discriminating means for discriminating whether or not the hue of the subject is green, and a hue of the subject is green by the green discriminating means. There is provided a digital camera provided with a white balance deviation correction means for weakening the degree of white balance adjustment by the white balance adjustment means when it is determined that there is.

Here, R / G is the ratio of the signal intensity of the R (red) component and the signal intensity of the G (green) component, and B / G is the ratio of the signal intensity of the B (blue) component and the G (green) component. It is the ratio to the signal strength.
R / G-B / G coordinates are R / G x-axis (horizontal axis), B / G
Is the coordinate along the y-axis (vertical axis).

In the digital camera of the present invention configured as described above, when the outdoor / indoor determination means determines that the shooting scene is an indoor scene, the color temperature determination means determines the color temperature of the subject. As a result, when it is determined that the color temperature of the subject is a color temperature close to the emission color of the white fluorescent lamp (around 4000 degrees), the green determining unit determines whether or not the hue of the subject is green. As a result, when it is determined that the color is green, the degree of white balance adjustment is weakened by the white balance deviation correction means. For example,
When the color temperature of the subject is determined to be an intermediate color temperature between the emission color of the white fluorescent lamp and the green of the plant, it is determined whether the hue of the subject is green and it is determined that it is the green of the plant. In this case, the white balance is set to be weaker than the white balance suitable for indoor shooting, and an appropriate white balance adjustment for outdoor shooting is performed.

With this, even when there is a possibility that the shooting scene is erroneously determined to be an indoor scene even though it is actually an outdoor scene, it is possible to appropriately and automatically adjust the white balance. It is possible to prevent the color reproducibility of the captured image from deteriorating.

Further, the green discriminating means calculates R / GB from the hue data of each area obtained by the hue detecting means.
It is desirable to find the slope of the hue distribution approximation line on the / G coordinate and determine whether the hue of the subject is green based on the slope.

In the above configuration, in the green discriminating means, when the inclination of the hue distribution approximation line on the R / GB / G coordinates from the hue data of each area is positive, for example, the inclination is positive (upward to the right), it is green. , If it is negative (downward to the right), it is determined to be the emission color of the white fluorescent lamp. As a result, even if it is easy to make an error in determining the hue, such as the green color of a plant outdoors in the dark, it is possible to accurately determine the hue.

Further, the green discriminating means converts the hue data of each area obtained by the hue detecting means into saturation data, and based on the number of pieces of data in the green detection area showing the range of saturation distribution of green. It is desirable to determine the saturation of the subject and determine whether the hue of the subject is green based on the determination result and the inclination.

Only by determining whether or not the hue of the subject is green on the basis of the inclination of the hue distribution approximation line on the R / GB / G coordinates described above, it is only necessary to determine whether or not the hue of the subject is green.
When shooting under the light, there is a possibility that the hue of the subject is erroneously determined to be all green. Therefore, in the green discriminating means, the hue data of each area is converted into the saturation data (La
b space data, YCrCb space data, etc.),
Whether or not the hue of the subject is green is determined based on the determination result and the inclination based on the number of pieces of hue data in the area that falls within the green detection region indicating the range of the saturation distribution of green. To determine. As a result, even if it is easy to make an error in determining the hue, such as the green color of a plant in the dark outdoors and the gray color under a green light source such as a mercury lamp, it is possible to more accurately determine the color difference.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a functional configuration of a digital camera according to an embodiment of the present invention.

In the digital camera of this embodiment,
The solid-state imaging device (C
The subject image formed on the light receiving surface of the CD) 13 is converted by each element of the solid-state image pickup device (CCD) 13 into a signal charge of an amount corresponding to the amount of incident light and accumulated. The signal charge accumulated in each element is read out to the shift register by the read gate pulse given from the CCD drive circuit 14, and sequentially read out as a voltage signal corresponding to the signal charge by the register transfer pulse. The CCD 13 has a so-called electronic shutter function capable of sweeping out the accumulated signal charge by a shutter gate pulse and controlling the charge accumulation time (shutter speed).

The voltage signal sequentially read from the CCD 13 is sent to a correlated double sampling circuit (CDS circuit) 15, where the R, G, B signals for each pixel are sampled and held, and the A / D converter is used. Sent to 16. A / D
The converter 16 has R, which are sequentially supplied from the CDS circuit 15,
The G and B signals are converted into 10-bit (0 to 1023) digital R, G and B signals and output. The CCD drive circuit 14, the CDS circuit 15 and the A / D converter 16 are driven in synchronization with a timing signal supplied from the timing generation circuit 17.

R, G output from the A / D converter 16
The B signal is sent to the CPU 19 via the integrating circuit 35, is temporarily stored in the memory 18, and then is sent to the digital signal processing circuit 20 and the lightness / hue detection circuit 50. A multiplier 536 is provided between the integrating circuit 35 and the CPU 19.
R, 36G, and 36B are provided, and a multiplier 536 is provided.
Adjustment gain values for adjusting the variations of the devices are input to R, 36G, and 36B.

The digital signal processing circuit 20 comprises a synchronizing circuit 21, a white balance adjusting circuit 22, a gamma correcting circuit 23, a YC signal generating circuit 24 and a memory 25. The synchronization circuit 21 converts the dot-sequential R, G, B signals read from the memory 18 into a simultaneous system,
White balance adjustment circuit 22 for R, G, B signals simultaneously
Output to.

The white balance adjusting circuit 22 has R,
The multipliers 22R, 22G, and 22B for increasing and decreasing the digital values of the G and B signals, respectively,
The G and B signals are applied to multipliers 22R, 22G and 22B, respectively.
Added to. Gain values Rg, Gg, and Bg from the white balance deviation correction circuit 30 are added to the other inputs of the multipliers 22R, 22G, and 22B, respectively.
Each of 22G and 22B multiplies two inputs, and outputs R ′, G ′, and B ′ signals whose white balance has been adjusted by this multiplication to the gamma correction circuit 23.

The gamma correction circuit 23 changes the input / output characteristics so that the white balance-adjusted R ', G', and B'signals have desired gamma characteristics, and a 10-bit signal is an 8-bit signal. And output to the YC signal generation circuit 24. The YC signal generation circuit 24 uses the gamma-corrected R, G, and B signals to output the lightness signal Y and the chroma signal C.
Create r and Cb. The lightness signal Y and the chroma signals Cr and Cb (YC signal) are stored in the memory 25. The YC signal stored in the memory 25 at the time of shooting is compressed into a predetermined format by a compression circuit (not shown) and then recorded on a recording medium such as a memory card.

The lightness / hue detection circuit 50 subdivides the subject image into a plurality of areas (here, 64.times.64 divisions) from the R, G, and B signals read from the memory 18, and the hue data of each area. (R, G, B) and brightness data (Y) are created and given to the outdoor / indoor discrimination circuit 70.

The outdoor / indoor discrimination circuit 70 determines whether the shooting scene is an outdoor scene or an indoor scene based on the hue data (R, G, B) and the brightness data (Y) from the brightness / hue detection circuit 50. It is determined whether or not there is, and the determination result (shooting scene determination result) is the white balance deviation correction circuit 3
0 and color temperature discrimination circuit 60. To the color temperature discrimination circuit 60, the hue data (R, G, B) and the lightness data (Y) from the lightness / hue detection circuit 50 are given together with the photographing scene discrimination result.

The color temperature discriminating circuit 60, when the outdoor / indoor discriminating circuit 70 discriminates that the photographed scene is an indoor scene, the color temperature discriminating circuit 60 is based on the hue data (R, G, B) and the lightness data (Y). Color temperature from 7000 to 200
It discriminates in the range of 0 degree and sends the result to the green discrimination circuit 40.

When the color temperature determination circuit 60 determines that the color temperature of the subject is an intermediate color temperature (around 4000 degrees) between the emission color of the white fluorescent lamp and the green of the plant, the green determination circuit 40 determines the brightness. Based on the hue data of each area of the subject image obtained by the hue detection circuit 50, it is determined whether the hue of the subject is green of a plant. The details of the discrimination processing and the saturation data creation processing in the green discrimination circuit 40 will be described in detail later.

The white balance deviation correction circuit 30 includes
The indoor / outdoor discrimination circuit 70 inputs a discrimination result as to whether the shooting scene is an outdoor scene or an indoor scene, and the green discrimination circuit 40 inputs a correction value according to the shooting scene discrimination result. The white balance shift correction circuit 30 determines the gain values Rg and G according to the result of the shooting scene determination.
g, Bg are determined, and the gain values Rg, Gg, Bg are corrected according to the correction value given from the green discriminating circuit 40, and then given to the white balance adjusting circuit 22. The correction value indicates the degree of correction of the gain values Rg, Gg, and Bg when it is determined that the shooting scene is an indoor scene. The correction value is 0 when it is determined that the shooting scene is an outdoor scene. Therefore, in that case, the gain values Rg, Gg, and
Bg is given to the white balance adjusting circuit 22 as it is.

The green discrimination circuit 40 includes a first discrimination processing section 41,
It has a second determination processing unit 42 and a final determination unit 45. The first discrimination processing unit 41, based on the hue data (RGB) of each area, for the subject image whose color temperature is determined to be around 4000 degrees by the color temperature discrimination circuit 60, R / G-B / G shown in FIG. The inclination of the hue distribution approximation line on the coordinates is obtained, based on the obtained inclination, it is determined whether the hue of the subject is green of a plant, and the determination result is sent to the final determination unit 45.

At this time, the green discriminating circuit 40 firstly divides the subject image into small pieces and produces 64 × 64 pieces of hue data (RGB).
It is checked how many of them enter the green detection frame 81 on the R / GB / G coordinates in FIG. 3, and if the number is equal to or more than a predetermined number, it is determined that the hue of the subject is green. Then, using the least squares method, the slope of the distribution approximate straight line of 64 × 64 pieces of hue data (RGB) on the R / GB / G coordinates is obtained, and the distribution example D1
If the inclination is positive, the hue of the subject is determined to be green of the plant, and if the inclination is negative as in the distribution example D2, it is determined to be the emission color of the white fluorescent lamp.

In many cases, hue data (RGB) having a strong blue tint is a scene in which a shooting scene is erroneously determined to be an indoor scene although it is actually an outdoor scene.
The hue data (RGB) is R / G because it contains a lot of
-R / G from the point where the B / G value on the B / G coordinate is large
Values and B / G values are both small. Therefore, in such a case where the photographic scene is erroneously discriminated, the slope of the hue distribution approximation line is positive. On the other hand, when the shooting scene is an indoor scene, the emission color of the white fluorescent lamp used as the light source has a very strong yellow color, so that the hue data (RGB) has an R / G value of 1 from within the green detection frame 81. Near B
/ G tends to be distributed up to a very small value.
Therefore, in this case, the gradient of the hue distribution approximation line is negative. In this way, it is possible to determine whether the hue of the subject is the green of a plant or the emission color of a white fluorescent lamp from the slope of the hue distribution approximation line.

As shown in FIG. 2, the second discrimination processing section 42 has a Lab converting section 43 and an area determining section 44. The Lab conversion unit 43 converts the hue data (RGB) sent from the color temperature determination circuit 60 into the saturation data (Lab).
To the area determination unit 44. Area determination unit 44
Is the saturation data (La that enters the green detection area 82 indicating the range of the saturation distribution of the green of the plant on the Lab space coordinates shown in FIG. 4).
The saturation of the subject is obtained from the number in b), that is, the number of areas, and the result is sent to the final determination unit 45.

The final judgment section 45 is based on the judgment result by the first judgment processing section 41 as to whether or not the hue of the object is green of a plant, and the saturation of the object calculated by the second judgment processing section 42. Then, it is finally determined whether or not the hue of the subject is green of a plant, and a correction value according to the saturation of the subject is given to the white balance deviation correction circuit 30.

As shown in FIG. 4, the green detection area 82 showing the range of the saturation distribution of the green of the plant on the Lab space coordinate is composed of an area A having a low saturation and an area B having a high saturation. From the area determination unit 44 to the final determination unit 45, the number information of the saturation data (Lab) in each of the A area, the B area, and the other areas is sent as the information about the saturation of the subject. The final determination unit 45 determines the correction value according to the ratio of the number of saturation data (Lab) in each of the A area, the B area, and the other areas. That is, when a predetermined number or more is entered in the area A, a correction value is determined so as to enhance the degree of white balance adjustment in proportion to the number, and when a predetermined number or more is entered in the area B, the correction value is proportional to the number. To determine the correction value so as to weaken the degree of white balance adjustment.

The CPU 19 integrally controls each circuit based on an input from the camera operation unit 31 including a shutter button, etc., and executes a series of controls such as autofocus control and automatic exposure control to perform a photographing operation of this digital camera. To control.

The camera operation section 31 is provided with a photographing mode selection dial. By operating the shooting mode selection dial, either the automatic scene detection mode, in which the digital camera automatically determines the shooting scene and shooting, or the manual shooting mode, in which the user sets the shooting scene and shoots You can choose. In the manual shooting mode, it is possible to select a mountain mode more suitable for shooting a mountain scene. In the mountain mode, the gain values Rg, Gg, and Bg set in advance so that the green of the plant can be clearly seen are CPU1.
9 is applied to the white balance adjusting circuit 22, so that the color ferria phenomenon does not occur.

Next, the operation of the digital camera configured as described above will be described with reference to the flowchart of FIG.

When the photographing operation is performed in the automatic scene discrimination mode, the digital camera of this embodiment executes the photographing (step S1) and the outdoor / indoor discrimination circuit 70.
At, it is determined whether the shooting scene is an outdoor scene or an indoor scene (step S2). The result of the shooting scene determination is the white balance control circuit 30 and the color temperature determination circuit 6.
Sent to 0. When it is determined that it is an outdoor scene (Yes in step S2), the color temperature determination circuit 60 does not perform color temperature determination, and passes the shooting scene determination result received from the outdoor indoor determination circuit 70 to the green determination circuit 40. The green discriminating circuit 40 which has received the photographing scene discrimination result gives a signal indicating the correction value 0 to the white balance control circuit 30. As a result, the gain values Rg, Gg, Bg generated for the outdoor shooting scene in the white balance control circuit 30 are given to the white balance adjustment circuit 22 as they are. In this case, the photographed subject image is subjected to white balance adjustment for an outdoor shooting scene by the white balance adjustment circuit 22 (step S3), and then the gamma correction circuit 23, YC.
It is recorded on a recording medium such as a memory card through the signal generating circuit 24 and the memory 25 (step S10).

When it is determined that the shooting scene is an indoor scene (No in step S2), the color temperature determination circuit 6
The color temperature of the subject is determined at 0 (step S4).
As a result, when it is determined that the color temperature of the subject is not the intermediate color temperature (around 4000 degrees) between the emission color of the white fluorescent lamp and the green of the plant (No in step S4), the green determination circuit 40.
Does not perform the discrimination process, and gives a signal indicating the correction value 0 to the white balance control circuit 30. In this case, the photographed subject image is subjected to white balance adjustment for an indoor photography scene by the white balance adjustment circuit 22 (step S5), and then the gamma correction circuit 23 and the YC signal creation circuit 24 are provided.
Then, it is recorded on a recording medium such as a memory card via the memory 25 (step S10).

When it is determined that the color temperature of the subject is an intermediate color temperature between the emission color of the white fluorescent lamp and the green of the plant (around 4000 degrees) (Yes in step S4), the green determination circuit 4
In the case of 0, the first discrimination processing unit 41 discriminates whether or not the hue of the subject is the green of a plant based on whether the inclination of the hue distribution approximation line on the R / GB / G coordinates is positive or negative (step S6). In the second discrimination processing unit 42, the chroma discrimination processing for obtaining the number of chroma data (Lab) in each of the A area, the B area, and the other areas of the green detection area 82 (step FIG. 4) is performed. The process is performed (step S7), and each result is given to the final determination unit 45.

The final judgment section 45 judges that the first judgment processing section 41 does not judge that the plant is green, that is, if the slope of the hue distribution approximation line is negative (No in step S8). ), It is finally determined that the hue of the subject is not green of a plant, and a signal showing a correction value 0 is given to the white balance control circuit 30. In this case, the photographed subject image is subjected to white balance adjustment for an indoor photography scene by the white balance adjustment circuit 22 (step S
5), through the gamma correction circuit 23, the YC signal generation circuit 24, and the memory 25, it is recorded on a recording medium such as a memory card (step S10).

When the first discrimination processing unit 41 discriminates that the plant is green, that is, when the inclination of the hue distribution approximation line is positive (Yes in step S6), the discrimination unit 4 is determined.
5 finally determines whether or not the hue of the subject is green of a plant based on the result of the saturation determination process (step S7) (step S8). Even when it is finally determined that the hue of the subject is not the green of the plant (N in step S8)
o), a signal indicating the correction value 0 is given from the judgment unit 45 to the white balance control circuit 30. Then, the photographed subject image is subjected to white balance adjustment for an indoor photographing scene by the white balance adjustment circuit 22 (step S5), and then the gamma correction circuit 23 and the YC signal generation circuit 2
It is recorded on a recording medium such as a memory card through the memory 4 and the memory 25 (step S10).

When the final judging section 45 finally judges that the hue of the subject is green of the plant (Yes in step S8).
s), a correction value according to the saturation of the subject is given to the white balance deviation correction circuit 30. This correction value weakens the degree of white balance adjustment as the saturation of the subject is higher, that is, the hue of the subject is more likely to be green of plants and less likely to be the emission color of the green light source. It is determined.

The white balance shift correction circuit 30 first generates gain values Rg, Gg, Bg for indoor shooting scenes, and receives the gain values Rg, Gg, Bg from the final determination section 45 of the green determination circuit 40. The value is corrected according to the value and then applied to the white balance adjustment circuit 22. That is, in this case, the white balance adjustment circuit 22 performs white balance adjustment for an indoor shooting scene on the photographed subject image.
The gain values Rg and Gg are set so that the degree of white balance adjustment is weakened according to the correction value received from the subject, as the hue of the subject is likely to be green of a plant and the emission color of the mercury lamp is less likely to be. , Bg are corrected. And
After the white balance adjustment circuit 22 performs white balance adjustment (white balance adjustment according to saturation) in accordance with the corrected gain values Rg, Gg, and Bg (step S9), the gamma correction circuit 23, Y
It is recorded on a recording medium such as a memory card via the C signal generating circuit 24 and the memory 25 (step S10).

As described above, in the above embodiment, even when the outdoor / indoor discrimination circuit 70 discriminates that the shooting scene is indoors, the color temperature discrimination circuit 60 determines that the color temperature of the subject is a white fluorescent lamp. When it is determined that the color temperature is between the luminescent color of the green color and the green color of the plant (around 4000 degrees), the green determination circuit 40 further determines whether the hue of the subject is the green color of the plant. Then, as a result, when it is determined that the color of the plant is green, the white balance deviation correction circuit 30 makes the degree of white balance adjustment weaker than the degree of white balance adjustment for indoor shooting. As a result, even if the shooting scene is mistakenly determined to be an indoor scene even though it is an outdoor scene, the green color of the outdoor plant is regarded as the emission color of the white fluorescent lamp used for indoor lighting. It is possible to prevent misidentification, and it is possible to shoot by automatically adjusting the white balance so as not to deteriorate the color reproducibility.

Therefore, when it is determined whether the shooting scene is an outdoor scene or an indoor scene and the white balance is automatically adjusted according to the result of the determination, the green scene of the outdoor plant is changed to the indoor scene. Therefore, it is possible to prevent color ferria due to the erroneous determination that

Moreover, in the above embodiment, the approximate straight line of the hue distribution on the R / GB / G coordinates obtained from the hue data of each area of the subject by the first determination processing unit 41 in the green discrimination circuit 40. Based on the inclination, it is determined whether the hue of the subject is green of a plant, and the second determination processing unit 42
Then, the saturation of the subject is obtained, and based on the determination results of both determination processing units 41 and 42, the final determination unit 45 finally determines whether or not the hue of the subject is green of plants. Therefore, it is possible to prevent the emission color of the green light source from being erroneously determined to be the green color of the plant.

Further, in the above-described embodiment, the degree of white balance adjustment is weakened as the hue of the subject is likely to be green of a plant and the emission color of the mercury lamp is less likely to occur. Good color reproducibility can be realized.

In the digital camera of the above embodiment, a dedicated circuit for preventing the occurrence of the color ferria phenomenon, that is, the white balance deviation correction circuit 30, the green discrimination circuit 40, the brightness / hue detection circuit 50, the color Although the temperature determination circuit 60 and the outdoor / indoor determination circuit 70 are provided, the functions of these circuits may be realized by the CPU 19.

The second determination processing section 42 and the final determination section 45 in the green determination circuit 40 may be omitted if it is not taken into consideration that photographing is performed under a green light source. That is, the green discriminating circuit 40 may have only the function of the first discriminating processing unit 41.

[0050]

As described above, according to the present invention, there is a risk of misidentifying an indoor scene such as a dark forest or a forest even though the shooting scene is actually an outdoor scene. Even in some cases, it is possible to provide a digital camera capable of automatically adjusting the white balance appropriately.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a functional configuration of a digital camera according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a second determination processing section in FIG.

FIG. 3 is a diagram showing emission colors of various light sources and hue detection frames of various subjects on R / GB / G coordinates.

FIG. 4 is a diagram showing a green detection area on a Lab space coordinate indicating color saturation.

5 is a flowchart showing the operation contents of the digital camera of FIG.

[Explanation of symbols]

18 memory 19 CPU 20 Digital signal processing circuit 22 White balance adjustment circuit 30 White balance deviation correction circuit 35 integrating circuit 40 Green discrimination circuit 41 First Discrimination Processing Unit 42 Second Discrimination Processing Unit 45 Final judgment section 43 Lab converter 44 area determination unit 50 brightness / hue detection circuit 60 color temperature discrimination circuit 70 Outdoor / indoor discrimination circuit 81 Green detection frame 82 Green detection area

Claims (3)

[Claims] 1. A lightness detecting means for detecting the lightness of a subject, a hue detecting means for dividing an image of the subject into a plurality of areas to detect a hue of each area, and lightness data obtained by the lightness detecting means. And an indoor / outdoor discrimination unit for discriminating whether the shooting scene is an outdoor scene or an indoor scene based on the hue data of each area obtained by the hue detection unit, and the indoor / outdoor discrimination unit by the outdoor / indoor discrimination unit. When it is determined to be a scene, a color temperature determination unit that determines the color temperature of the subject based on the lightness data and the hue data; and a color temperature determination unit that determines the color temperature of the emission color of the white fluorescent lamp. R / of the hue data of each area
When the hue of the subject is determined to be green by the green determination means that determines whether the hue of the subject is green according to the distribution on the GB / G coordinates. A digital camera, further comprising: a white balance deviation correction unit that weakens the degree of white balance adjustment by the white balance adjustment unit. 2. The green discriminating means uses R / G-B / G from the hue data of each area obtained by the hue detecting means.
The digital camera according to claim 1, wherein a slope of the hue distribution approximation line on the coordinates is obtained, and whether or not the hue of the subject is green is determined based on the slope. 3. The green discriminating means converts the hue data of each area obtained by the hue detecting means into saturation data, and determines the number of pieces of data in the green detection area indicating the range of saturation distribution of green. 3. The digital camera according to claim 1, wherein the saturation of the subject is determined, and whether the hue of the subject is green is determined based on the determination result and the inclination.