JP2003163944A - White balance-control method and digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white balance-control method for appropriately controlling white balance by precisely discriminating the kinds of light sources, and to provide a digital camera. <P>SOLUTION: A screen where a subject is imaged is divided into a plurality of areas. Color information for each divided area is obtained. Based on the color information, each area is applied to a detection frame for indicating the range of color distribution corresponding to the kinds of light sources. The number of areas that can be applied to each detection frame is obtained. At the same time, the luminance level of the subject and the quantity of infrared rays is detected. Based on the number of areas that can be applied to each detection frame, the luminance level of the subject, and the quantity of infrared rays, the light sources are discriminated for appropriately controlling white balance. <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 white balance control method and a digital camera, and more particularly to a white balance control method and a digital camera for performing an appropriate white balance control according to a light source type.

[0002]

2. Description of the Related Art As white balance control in a conventional digital camera, among red (R), green (G), and blue (B) color signals, the R signal of the entire screen is selected. The difference signal (RB) between the average value and the average value of the B signal is calculated, the gains of the R signal and the B signal are controlled so that the difference signal (RB) becomes 0, and the white balance is controlled. There are things I tried to do. In the case of this automatic white balance control method, there is a problem that the white balance is erroneously corrected when the color temperature distribution of the subject is non-uniform or there are many single colors.

Further, in the white balance control for setting the difference signal (RB) to 0, the difference signal (RB) becomes 0.
In the case of a scene that does not occur, even if the control range of the gains of the R signal and the B signal is limited according to the brightness level, the erroneous correction is reduced, and the white balance control suitable for the scene is performed. There was a problem that I could not do it.

Further, in the technique disclosed in Japanese Unexamined Patent Publication No. 8-32990, in order to identify a fluorescent lamp light source and perform an appropriate white balance control, the light source is a fluorescent lamp outdoors, particularly in a low-luminance outdoor. If infrared light is detected using an infrared sensor to avoid erroneous judgment, the fluorescent lamp is not corrected, and after confirming that infrared light is not detected, the color information of the fluorescent light is detected and the white balance is detected. The light is corrected.

However, although it is possible to distinguish between a low-luminance outdoor scene and an indoor fluorescent lamp scene by the above-described method, it is possible to perform an appropriate white balance correction in an indoor scene where fluorescent lamps and light bulbs are mixed. There wasn't. That is, both a fluorescent lamp and a light bulb are often turned on indoors, but the light bulb contains an infrared component having a wavelength of 780 nm or more as shown in FIG. Therefore, in a scene in which a fluorescent lamp and an electric bulb coexist, there is a problem that the fluorescent lamp correction is not performed at all and the white balance is not appropriately corrected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a white balance control method and a digital camera capable of appropriately discriminating light source types and performing appropriate white balance control. And

[0007]

In order to achieve the above object, a white balance control method according to a first aspect of the present invention comprises a step of detecting a brightness level of an object, a step of detecting the amount of infrared light, and an image of the object. The screen is divided into a plurality of areas, the step of acquiring color information for each area, based on the color information for each acquired area,
A step of obtaining a color distribution of each area, a step of determining a light source type based on the detected brightness level of the subject, an infrared light amount, and a color distribution, and a step of performing white balance control suitable for the determined light source type And include.

Further, the digital camera of the second invention is such that the brightness detecting means for detecting the brightness level of the object, the infrared detecting means for detecting the amount of infrared light, and the screen on which the object is imaged are divided into a plurality of areas. , Color information acquisition means for acquiring color information for each area, based on the acquired color information for each area, color distribution detection means for determining the color distribution of each area, and the brightness level of the detected subject, It is configured to include a discriminating unit that discriminates a light source type based on the amount of infrared light and a color distribution, and a control unit that performs white balance control suitable for the discriminated light source type.

According to the first and second aspects, the light source type is discriminated based on the luminance level of the subject, the amount of infrared light, and the color distribution obtained from the color information for each area. Since suitable white balance control is performed, it is possible to accurately determine the light source type, and thus it is possible to perform good white balance control suitable for the light source type.

In the color distributions of the first and second inventions, each area is applied to a detection frame indicating a range of color distribution corresponding to a plurality of predetermined light source types, and the number of areas applicable to each detection frame is determined. Can be obtained by

The white balance control suitable for the light source type can be performed by, for example, setting the gains of the R, G, and B signals to the gains preset according to the light source type.

Further, the color information of the first and second inventions is a ratio R / G, B / G of R, G, B signals in an area, and the detection frame has a range of R / G. The frame can be defined by the B / G range.

Further, the light source types of the first and second inventions include a shade, a fluorescent lamp, and a light bulb, and the detection frame includes a shade detection frame, a fluorescent lamp detection frame, and a light bulb detection frame. It is possible to identify the light source type for shade, fluorescent lamp, and light bulb.

Further, in determining the light source type, the probability of shade, the probability of fluorescent lamp and the probability of light bulb are calculated as follows: Probability of shade = Fo (outdoor) x Fs (shade) * Fb (blue sky) , Probability of fluorescent lightness = Fi1
(Indoors-likeness) × F (Fluorescent-likeness) × Fir (Infrared), probability of lightbulb-likeness = Fi2 (Indoorness) × Fd
The light source type may be calculated based on (light bulb likeness) × Fn (skin color), and the light source type having the highest probability among the calculated probabilities may be determined as the light source. However, Fo (outdoor likeness): a value of a function that represents the shade of the outdoors with a brightness level as a variable, Fi1 (likeness indoors): a value of a function that represents the likeness of a fluorescent lamp with a brightness level as a variable, and Fi2 (likeness of the interior): Fs (shadeness of shade), which is a function of the brightness level as a variable, and Fs (shadeness of shade): a value of a function of which shade is a predetermined brightness or less and whose number is within the shade detection frame , Fb (blue sky): an area having a predetermined brightness or more and a variable representing the number of areas that fall within the blue sky detection frame, F (fluorescent lamp-likeness): falling within the fluorescent lamp detection frame Fd (light bulb likeness), a value of a function that expresses the likeness of a fluorescent light with the number of areas as a variable: Fn (skin color), the value of a membership function that represents likeness of a light bulb with the number of areas within the light bulb detection frame as a variable. Within the skin color detection frame Function representing the skin color likelihood that the number of areas and variables that, to.

In this way, by calculating the probability of each light source type and determining the light source type with the highest probability among the calculated probabilities as the light source, the light source type can be determined more accurately and is appropriate. White balance control can be performed.

In the first and second aspects of the present invention, more appropriate white balance control can be performed by performing white balance control according to the probability of the determined light source.

According to the first and second aspects of the present invention, when the largest of the calculated probabilities is greater than or equal to a predetermined value, the light source type having that probability is determined as the light source, and when it is less than or equal to the predetermined value, the daylight is used as the light source. Can also be determined as

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an automatic white balance control method according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a digital camera to which an automatic white balance control method according to the present invention is applied.

The subject image formed on the light-receiving surface of the solid-state image pickup device (CCD) 14 through the taking lens 10 and the diaphragm 12 is converted into signal charges of the amount corresponding to the incident light amount of each sensor. The signal charge thus accumulated is CC
The read gate pulse applied from the D drive circuit 16 reads out to the shift register, and the register transfer pulse sequentially reads out as a voltage signal corresponding to the signal charge. Incidentally, the CCD 14 can sweep out the accumulated signal charge by a shutter gate pulse, thereby controlling the charge accumulation time (shutter speed).
It has a so-called electronic shutter function.

The voltage signal sequentially read from the CCD 14 is applied to a correlated double sampling circuit (CDS circuit) 18, where the R, G, B signals for each pixel are sampled and held, and the A / D converter is provided. 20 added. A
The / D converter 20 converts the R, G, B signals sequentially added from the CDS circuit 18 into digital R, G, B signals of 10 bits (0 to 1023) and outputs them. The CCD drive circuit 16, the CDS circuit 18, and the A / D converter 20 are
It is adapted to be driven in synchronization with a timing signal applied from the timing generation circuit 22.

R output from the A / D converter 18
The G, B signals are once stored in the memory 24, and then the R, G, B signals stored in the memory 24 are added to the digital signal processing circuit 26. Digital signal processing circuit 26
Is a synchronizing circuit 28, a white balance adjusting circuit 30,
Gamma correction circuit 32, YC signal generation circuit, and memory 3
It is composed of 6.

The synchronization circuit 28 converts the dot-sequential R, G, B signals read from the memory 24 into a simultaneous signal, and converts the R, G, B signals into R,
The G and B signals are simultaneously output to the white balance adjustment circuit 30. The white balance adjustment circuit 30 has R, G, B
Multiplier 30 for increasing / decreasing the digital value of each signal
It is composed of R, 30G and 30B, and the R, G and B signals are added to the multipliers 30R, 30G and 30B, respectively. The other inputs of the multipliers 30R, 30G, 30B are
Gain values Rg, Gg, and Bg for white balance control are added from the central processing unit (CPU) 38, and the multipliers 30R, 30G, and 30B each multiply two inputs, and the white balance is adjusted by this multiplication. The R ′, G ′ and B ′ signals are output to the gamma correction circuit 32. In addition, from the CPU 38 to the white balance adjustment circuit 30
The details of the gain values Rg, Gg, and Bg added to will be described later.

The gamma correction circuit 32 changes the input / output characteristics so that the white balance-adjusted R ', G', and B'signals have desired gamma characteristics, and the 10-bit signal is an 8-bit signal. And output to the YC signal creation circuit 34. The YC signal creation circuit 34 creates a luminance signal Y and chroma signals Cr and Cb from the gamma-corrected R, G, and B signals. The luminance signal Y and the chroma signals Cr and Cb (YC signals) are stored in the memory 36.

The YC signal stored in the memory 36 at the time of photographing is compressed into a predetermined format by a compression circuit (not shown) and then recorded in a recording medium such as a memory card. The CPU 38 inputs from the camera operation unit 40 including a shutter button and the like, inputs from the infrared sensor 43 via the A / D converter 45, and multipliers 50R and 50G.
Based on the input from the integrating circuit 48 via 50B, each circuit is comprehensively controlled, and control such as autofocus, automatic exposure control, and automatic white balance is performed.

This autofocus control is, for example, contrast AF in which the photographing lens 10 is moved so that the high frequency component of the G signal is maximized, and is driven so that the high frequency component of the G signal is maximized when the shutter button is half pressed. The taking lens 10 is moved to the in-focus position via the unit 42.

Further, the automatic exposure control is performed by R of one frame,
The subject brightness (shooting EV) is obtained based on the integrated value obtained by integrating the G and B signals, the aperture value and the shutter speed are determined based on this shooting EV, and the aperture 12 is driven via the aperture drive unit 44. The charge accumulation time is controlled by the electronic shutter so that the shutter speed becomes the determined shutter speed, the R, G, B signals of one frame are acquired again, and the photographing EV is obtained again. When the shutter button is half-pressed, the above photometric operation is repeated a plurality of times to obtain an accurate shooting EV, and the aperture value and shutter speed at the time of shooting are finally determined based on this shooting EV. Then, when the shutter button is fully pressed, the aperture 12 is driven via the aperture drive unit 44 so that the finally determined aperture value is obtained, and the charge accumulation time by the electronic shutter is obtained so as to obtain the determined shutter speed. To control.

Next, the white balance control method will be described. This digital camera has a strobe 46, and a low-brightness auto-emission mode in which the strobe 46 automatically emits light at low brightness by operating a strobe key (not shown), and forced light emission in which the strobe 46 emits light regardless of the subject brightness. It has a mode, a light emission prohibition mode for prohibiting the light emission of the strobe 46, and the like. Then, the white balance control according to these modes is performed.

White balance control in the forced light emission mode will be described. In the case of the forced light emission mode, since the strobe emits light regardless of the shooting EV value, white balance control suitable for the strobe light is performed.
That is, white balance gain values Rg, Gg, and Bg for performing good white balance on the strobe light are prepared in advance, and these gain values Rg, Gg, and B are prepared.
g is added to the white balance adjustment circuit 30.

Next, white balance control in the low brightness automatic light emission mode will be described with reference to the flowchart of FIG. In this case, the photographing EV value is acquired when the shutter button is half-pressed in step S10, and it is determined whether or not low-luminance light emission is performed based on the photographing EV value acquired in step S12. Shooting EV value is a predetermined value (10 EV)
In the following cases, it is determined that low-luminance light emission is performed, and step S
At 14, white balance control suitable for strobe light is performed. That is, the white balance gain values Rg, Gg, B for performing good white balance with respect to the strobe light.
g is prepared in advance, and these gain values Rg, G
g and Bg are added to the white balance adjustment circuit 30.

On the other hand, the photographing EV value is a predetermined value (10 EV)
In the above case, it is determined that low-luminance light emission is not performed, and in step S16, the entire screen is displayed in a plurality of areas (8 × in this embodiment).
(8 areas), and the average integrated value for each color of R, G, B signals is obtained for each area, and the ratio R / G of the integrated value of the R signal to the integrated value of the G signal and the B signal The ratio B / G between the integrated value of G and the integrated value of the G signal is calculated.

The average integrated value of the R, G and B signals for each area is calculated by the integrating circuit 48 of FIG.
Added to U38. In addition, the integrating circuit 48 and the CPU
Multipliers 50R, 50G, and 50B are provided between the multipliers 38 and 38, and the multipliers 50R, 50G, and 50B are provided with an adjustment gain value for adjusting the variation of the devices.

Next, in step S18, R for each area
Based on the color information of / G and B / G, each area has a shade detection frame, a blue sky detection frame, a daylight color detection frame, a day white detection frame, a white detection frame, a skin color detection frame, and tungsten in the graph shown in FIG. It is determined which detection frame of the light bulb detection frame is included. Each detection frame is a frame shown on the graph shown in FIG. 3 in which the horizontal axis is R / G and the vertical axis is B / G, and the range of color distribution such as the light source type is defined for each detection frame. It is a thing.

It is to be noted that only areas having a predetermined luminance or less and having R / G and B / G color information falling within the detection frame are selected and put into the shade detection frame, and the blue sky detection frame has a predetermined range. Only the areas which are equal to or higher than the luminance and in which the color information of R / G and B / G falls within the detection frame are selected and inserted. Brightness of each area (E
V value Evi) is calculated by the following equation:

[0034]

[Equation 1]

It is calculated by However, "EV" is the shooting EV
The value, "Gi", represents the average integrated value of G in each area. Incidentally, 45 in the above formula is an appropriate value among the values after A / D conversion. In the present embodiment, the predetermined brightness for the shade detection frame is 12, and the predetermined brightness for the blue detection frame is 12.5. This brightness value is not limited to the brightness value described above, and it goes without saying that different brightness values can be set.

In step S20, the number of areas included in each detection frame is detected, and in step S22, based on FIGS. 4 to 10, the type of light source, that is, the basis for determining the probability of each shooting scene. The values of the respective membership functions of the outdoor-likeness Fo, the indoor-likeness Fi, the shade-likeness Fs, the fluorescent-likeness (daylight color Fk, the neutral white Fh, and white Fw), the tungsten light bulb-likeness Fd, and the skin color Fn are obtained. 4 and 5 show a membership function in which the shooting EV value is used as a variable, FIG. 4 is a membership function representing the outdoorness Fo, and FIG. 5 is a membership function representing the indoorness Fi. 6 to 10 show a membership function in which the number of areas included in each detection frame is used as a variable. FIG. 6 shows a membership function showing the shade Fs, and FIG. 7 shows members of the blue sky Fb. Ship function, FIG. 8 shows the fluorescent light F (daylight color Fk, daylight white Fh, white F
w) membership function, FIG. 9 is a membership function representing tungsten light bulb likeness Fd, and FIG. 10 is skin color Fn.
Is a membership function of.

Next, in step S24, the infrared sensor 4
The infrared output from 3 is taken in, and the value Fir (infrared) of the membership function of the infrared output is obtained based on this infrared output. The infrared output membership function is shown in Figure 1.
As shown in 1, it is a membership function used when evaluating the likeness of a fluorescent lamp having an infrared output as a variable. This membership function has a negative effect on the evaluation of the fluorescent lightness as the infrared light output increases. This is because, as shown in FIG. 12, a fluorescent lamp hardly contains wavelength components of 700 nm or longer, so if the output from an infrared sensor that senses light of 780 nm or longer is large, the probability that the light source is a fluorescent lamp is high. Because it will be low. By using the membership function of the infrared output to calculate the evaluation value for the light source of the fluorescent lamp as described later, low brightness outdoors (shade)
It is possible to prevent the light source from being erroneously determined to be a fluorescent lamp in the leaf green scene.

In step S26, an evaluation value of shade-likeness, an evaluation value of daylight color of fluorescent light, an evaluation value of daylight of fluorescent light, an evaluation value of whiteness of fluorescent light, which are probabilities of being the respective light sources according to the following equation, The evaluation value of the likeness of the tungsten bulb is calculated.

First, the calculation of the evaluation value of the shade likeness will be described. The evaluation value of shade-likeness is calculated by the following formula.

[0040]

[Equation 2]

In the above equation, Fo (outdoor likeness) is
It is the value of the membership function that expresses the outdoorness with the shooting EV value shown in FIG. 4 obtained in step S22 as a variable. Further, Fs (shadeness of shade) is a value of a membership function that represents shadeness with the number of areas included in the shade detection frame shown in FIG. 6 as a variable, and Fb (blue sky) is the sky detection shown in FIG. This is the value of the membership function that represents the blue sky with the number of areas within the frame as a variable. In addition, Fb (blue sky) is
The larger the number of areas included in the blue sky detection frame, the lower the evaluation value of shade-likeness.

Next, the evaluation value of daylight color likeness of fluorescent light, the evaluation value of daylightness like fluorescent light, the evaluation value of whiteness like fluorescent light,
The evaluation value of the likeness of the tungsten bulb is calculated. Each evaluation value is calculated by the following formula.

[0043]

[Equation 3]

[0044]

[Equation 4]

[0045]

[Equation 5]

[0046]

[Equation 6]

F in the above equations 3 to 5
i1 (indoorness) is a value of a membership function that represents indoorness (fluorescent lamp) likeness in which the shooting EV value shown in FIG. 5 is a variable, and Fi2 (indoorness) in the expression (6) is
It is a value of a membership function representing the indoor (tungsten light bulb) likeness with the shooting EV value (numerical value in parentheses) shown in FIG. 6 as a variable.

Further, Fk (like fluorescent daylight color), Fh (like fluorescent daylight white), Fw (like fluorescent light white), Fd (like tungsten light bulb) in the expressions [3] to [6], and F (skin color) is the value of each membership function detected in step S22. F (skin)
Operates to lower the evaluation value of the tungsten light bulb likeness as the number of areas in the skin color detection frame increases. This is because if the white balance control is strongly applied to the color of the tungsten light bulb in a scene with a flesh tone, the reddish tint becomes whitish and the complexion becomes worse.

From each evaluation value obtained as described above,
The probability of being each light source is shown, and the higher the evaluation value, the higher the probability of being that light source. Therefore, step S28
Then, the maximum value of the evaluation values of the shooting scenes obtained in step S26 is extracted, and in step S30, the extracted maximum evaluation value is a predetermined reference value (in this embodiment,
0.47) or more is determined. The maximum evaluation value is 0.
In the case of 47 or more, it is determined that the light source is the light source of the shooting scene having the maximum evaluation value, and the white balance control suitable for the light source is performed in step S32.

On the other hand, when the maximum evaluation value is less than 0.47, it is determined that the shooting scene is daylight (clear), and the white balance control suitable for daylight is performed in step S34.

In the present embodiment, the evaluation value 0.47
Was used as the discrimination reference value with the daylight, but another value can be used as the discrimination reference value with the daylight.

The white balance control suitable for each of these shooting scenes is performed by the white balance gain values Rg, G for performing good white balance for each shooting scene.
g and Bg are prepared in advance, and these gain values R
This is performed by adding g, Gg, and Bg to the white balance adjustment circuit 30.

The preset gain values are Rg, Gg, B
g, and R, G, and B are signals to be corrected, the correction result in the white balance adjustment circuit 30 is R ′, G ′, and B ′.
Then, R ', G', B'is

[0054]

[Equation 7]

Is represented by

Further, the gain value may be changed according to the degree of scene (evaluation value) as shown in the following equation.

[0057]

[Equation 8]

The preset light source type gain values Rg, Gg, and Bg are empirically set within a range of about 0.9 to 1.5. Moreover, when the gain value is changed according to the evaluation value, the continuity of the scene is maintained.

The white balance control in the light emission prohibition mode is performed in the same manner as in the case of not emitting the low brightness light in the low brightness automatic light emission mode described above.

Further, in the present embodiment, the evaluation value for detecting the light source type is calculated on the basis of the formulas [2] to [6]. However, other factors (other memberships) are calculated. (Function) may be added for calculation. Further, the light source type is not limited to this embodiment, and for example, a fluorescent lamp is
It may be of two types.

According to this embodiment, the subject brightness (EV
Value) and the color information from the CCD output, in addition to the color information from the CCD output, the membership function that uses the infrared sensor output as a variable is used to determine the light source type. It is possible to prevent erroneous determination that the white balance is properly controlled. Also, in a shooting scene in which a tungsten bulb containing an infrared component and a fluorescent lamp containing no infrared component coexist, if the gain value for white balance control is changed according to the degree of the scene (evaluation value), Intermediate correction can be performed for each light source, and more appropriate white balance control can be performed.

[0062]

As described above, according to the present invention, the type of light source can be accurately discriminated, and thus the white balance control suitable for the type of light source can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital camera to which an automatic white balance control method according to the present invention is applied.

FIG. 2 is a flowchart of an automatic white balance control process.

FIG. 3 is a graph showing a detection frame as a range of color distribution of a light source type.

FIG. 4 is a graph showing a membership function representing outdoorness.

FIG. 5 is a graph showing a membership function representing indoorness.

FIG. 6 is a graph showing a membership function representing the shade-likeness.

FIG. 7 is a graph showing a membership function of blue sky.

FIG. 8 is a graph showing a membership function representing the uniqueness of a fluorescent lamp.

FIG. 9 is a graph showing a membership function representing the likeness of a tungsten light bulb.

FIG. 10 is a graph showing a membership function of skin color.

FIG. 11 is a graph showing a membership function of infrared rays.

FIG. 12 is a graph showing the spectral characteristics of each light source.

[Explanation of symbols]

10 Shooting lens 14 CCD 26 Digital signal processor 38 CPU 43 infrared sensor 48 integrating circuit S10 EV value acquisition S16 R / G, B / G calculation S18 Detection frame judgment of each area S20 Detection of the number of areas in each detection frame S22 Membership function detection S24 Membership function detection based on infrared output S26 Calculation of each evaluation value

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5C065 AA01 AA03 BB02 BB16 CC01                       CC02 CC03 CC09 GG18 GG30                 5C066 AA01 CA17 EA14 EE03 GA01                       GA02 GA05 KD06 KE07 KM02                       KM10

Claims (14)

[Claims] 1. A step of detecting the brightness level of a subject, a step of detecting the amount of infrared light, a step of dividing a screen image of the subject into a plurality of areas, and acquiring color information for each area, A step of obtaining a color distribution of each area based on the acquired color information for each area; a step of determining a light source type based on the detected brightness level of the subject, an infrared light amount, and a color distribution; A white balance control method comprising the step of performing white balance control suitable for the determined light source type. 2. The color distribution is obtained by applying each area to a detection frame indicating a range of color distribution corresponding to a plurality of predetermined light source types, and obtaining the number of areas fitted to each detection frame. The white balance control method according to claim 1. 3. The color information is a ratio R / G and B / G of R, G and B signals in an area, and the detection frame is R / G.
The white balance control method according to claim 1 or 2, wherein the frame is a frame defined by a G range and a B / G range. 4. The light source type includes a shade, a fluorescent lamp, and a light bulb, and the detection frame includes a shade detection frame, a fluorescent lamp detection frame, and a light bulb detection frame. 1
The white balance control method described in the item. 5. The light source type is determined by the following formula: probability of shade likeness, probability of fluorescent lamp likeness, and probability of light bulb like formula: shade like probability = Fo (outdoor likeness) × Fs (shade likeness) × Fb (blue sky) Fluorescent lamp-like probability = Fi1 (indoor feeling) × F (fluorescent lamp-like) × Fir (infrared) light bulb like probability = Fi2 (indoor like) × Fd (light bulb like) × Fn (skin color) The white balance control method according to claim 4, wherein the light source type having the highest probability among the calculated probabilities is determined as a light source. However, Fo (outdoor likeness): a value of a function representing the outdoor shade likeness with a brightness level as a variable,
Fi1 (indoors-likeness): a value of a function representing the fluorescent lightness with a brightness level as a variable, Fi2 (indoorness): a value of a function representing the lightbulb-likeness with a brightness level as a variable, Fs (shadelikeness): a predetermined brightness The following areas, which are the values of a function that expresses the shade likeness, where the number of areas that fall within the shade detection frame is a variable, Fb (blue sky): An area with a predetermined brightness or higher that falls within the blue sky detection frame. F (fluorescent lamp-likeness), the value of a function representing the blue sky whose number is the variable, Fd (likeness of a light bulb), a value of a function representing the fluorescent lamp-likeness, in which the number of areas within the fluorescent lamp detection frame is a variable Let Fn (skin color) be a value of a function representing the likeness of a light bulb with the number of areas within the detection frame as a variable, and Fn (skin color): a value of a function representing the likeness of skin color with the number of areas within the detection frame as a variable. 6. The white balance control method according to claim 5, wherein the white balance control is performed according to the probability of the determined light source. 7. The light source type having the highest probability of the calculated probabilities is equal to or higher than a predetermined value as a light source, and the daylight is a light source when the probability is equal to or lower than the predetermined value. The white balance control method according to claim 5 or 6. 8. A brightness detecting means for detecting a brightness level of a subject, an infrared detecting means for detecting a light amount of infrared rays, a screen on which a subject is imaged is divided into a plurality of areas, and color information is obtained for each area. Color information acquisition means, based on the acquired color information for each area, color distribution detection means for obtaining the color distribution of each area, based on the detected brightness level of the subject, the amount of infrared light, and the color distribution A digital camera comprising: a discriminating unit for discriminating a light source type according to the above, and a control unit for performing white balance control suitable for the discriminated light source type. 9. The color distribution can be obtained by applying each area to a detection frame indicating a range of color distribution corresponding to a plurality of light source types set in advance, and obtaining the number of areas applicable to each detection frame. The digital camera according to claim 8, wherein the digital camera is a digital camera. 10. The color information is R, G, B in an area.
Signal ratios R / G and B / G, and the detection frame is R
The digital camera according to claim 8 or 9, which is a frame defined by a range of / G and a range of B / G. 11. The light source type includes a shade, a fluorescent lamp, and a light bulb, and the detection frame includes a shade detection frame, a fluorescent lamp detection frame,
The digital camera according to claim 8, further comprising a light bulb detection frame. 12. The light source type is determined by the following formula: probability of shade, probability of fluorescent light, and probability of light bulb, probability of shade = Fo (outdoor) × Fs (shadow) Fb (blue sky) Probability of fluorescent light likeness = Fi1 (indoor feeling) × F (like fluorescent light) × Fir (infrared) Probability of light bulb likeness = Fi2 (indoor feeling) × Fd (light bulb likeness) × Fn (skin color) The digital camera according to claim 11, wherein the light source type having the highest probability of the calculated probabilities is determined as a light source. However, Fo (outdoor likeness): a value of a function representing the outdoor shade likeness with a brightness level as a variable, Fi1
(Indoorness): A value of a function that expresses the fluorescent light likeness with the brightness level as a variable, Fi2 (Indoorness): a value of a function that represents the lightbulb likeness with the brightness level as a variable, Fs (Shadow likeness): Below a predetermined brightness Value of a function representing the shade-likeness with the number of areas included in the shaded detection frame as a variable, Fb (blue sky): an area having a predetermined brightness or higher and an area included in the blue sky detection frame. F (value like a fluorescent lamp), a value of a function that represents the blue sky with the number of variables as a variable, F (value of a fluorescent lamp) that represents likeness of a fluorescent lamp that has the number of areas within the fluorescent lamp detection frame as a variable Fn, a value of a function expressing the likeness of a light bulb with the number of areas within the frame as a variable
(Skin color): A function representing the likelihood of skin color with the number of areas within the skin color detection frame as a variable. 13. The digital camera according to claim 12, wherein the white balance control is performed according to the probability of the determined light source. 14. The light source type having the maximum value is discriminated as a light source when the highest probability among the calculated probabilities is a predetermined value or more, and the daylight is discriminated as a light source when the probability is less than the predetermined value. The digital camera according to claim 12 or 13.