JP2010028366A - Electronic camera, camera system and light flashing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera which has a built-in type light flashing unit and is capable of performing appropriate white balance adjustment even when the number of times of light emission of the light flashing unit increases in the case of using a fixed white balance gain factor. <P>SOLUTION: The electronic camera includes an imaging element, a flash light-emitting part, a counter, a storage part, and a gain deriving part. The imaging element images an object to generate image signals, and the flash light-emitting part emits flash light to the object. The counter counts the number of times of the light emission of the flash light-emitting part, and the storage part stores the number of times of the light emission. The gain deriving part derives a gain value in the present number of times of the light emission on the basis of gain information indicating the change of the gain of the white balance corresponding to the number of times of the light emission when the flash light is emitted from the flash light-emitting part. A white balance adjustment part adjusts the white balance of the image signals on the basis of the gain value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic camera having a built-in flash device used for photographing and capable of adjusting white balance. The present invention also relates to a camera system including an external flash device and an electronic camera capable of adjusting white balance. Furthermore, the present invention relates to an external flash device.

  2. Description of the Related Art Conventionally, an electronic camera having a function of adjusting a white balance of an image signal obtained by capturing an image of a subject is known (see, for example, Patent Document 1).

There are roughly three methods for adjusting the white balance. Specifically, (1) an achromatic object is photographed in advance in the photographing environment, and R = G = B based on the acquired red (R), green (G), and blue (B) signals. R and B gain coefficients are calculated (G / R and G / B, etc.), and the calculated gain coefficients are set. (2) Gain coefficients are calculated by various original algorithms based on the captured images. And (3) a method of setting a preset gain coefficient in accordance with an environmental temperature (bulb, clear sky, cloudy sky, shade, flash device, etc.) assumed in advance by a camera manufacturer or the like. .
JP 2003-224864 A

  By the way, when a flash is emitted from the flash device toward the subject, the subject is controlled by a specific color temperature of the flash device. In particular, when the subject is not irradiated with any other light source, the influence is conspicuous, but the color temperature changes due to the number of times the flash device emits light.

  Here, in the methods (1) and (2) above, even if the specific color temperature of the flash device changes, feedback is applied by shooting in the state where the color temperature has changed, so the change in the color temperature Not easily affected. For example, in the case of the method (1), since an achromatic subject is photographed, R = G = B based on the acquired R, G, and B signals even if the specific color temperature of the flash device changes. R and B gain coefficients can be calculated such that In the case of the method (2), the gain coefficient can be calculated from the captured image even if the specific color temperature of the flash device changes.

  However, in the case of the method (3), when the specific color temperature of the flash device changes with a preset fixed gain coefficient, the white balance of the photographed image is affected. Specifically, for example, the color temperature of R decreases as the number of times of light emission increases. Therefore, in the electronic camera disclosed in Patent Document 1, when the white balance is adjusted by the method (3), there is a problem that the white balance is not properly adjusted when the predetermined number of times of light emission is exceeded. .

  In recent years, electronic cameras tend to be miniaturized. Therefore, if the flash device is also downsized, the xenon tube used in the flash device must be downsized. However, since there is a limit to the miniaturization of the xenon tube, measures such as increasing the gas pressure inside the xenon tube are required to maintain the conventional performance. Therefore, when the gas pressure of the xenon tube is increased, there arises a new problem that the change in the color temperature is increased depending on the number of times of light emission.

  Therefore, in view of the above circumstances, the present invention includes a built-in flash device, and when a fixed white balance gain coefficient is used, the white balance is adjusted appropriately even if the number of flashes of the flash device increases. An object of the present invention is to provide an electronic camera.

  Another object of the present invention is to provide a camera system in which an external flash device is attached to an electronic camera and an appropriate white balance can be adjusted even if the flash device emits more light. Objective.

  Still another object of the present invention is to provide an external flash device that eliminates a decrease in color temperature caused by an increase in the number of times of light emission.

  An electronic camera according to a first invention includes an imaging device, a flash light emitting unit, a counter, a storage unit, and a gain deriving unit. The imaging element images a subject and generates an image signal. The flash light emitting unit emits flash light on the subject. The counter counts the number of times the flash light emitting section emits light. The storage unit stores the number of times of light emission. The gain deriving unit derives a gain value at the current number of times of light emission based on gain information indicating a change in white balance gain according to the number of times of light emission when flash light emission is performed from the flash light emitting unit. The white balance adjustment unit adjusts the white balance of the image signal based on the gain value.

  A flash device according to a second invention includes a counter, a storage unit, a gain deriving unit, and a first communication unit. The counter counts the number of flashes emitted toward the subject. The storage unit stores the number of times of light emission. The gain deriving unit derives a gain value at the current number of times of light emission based on gain information indicating a change in gain of white balance according to the number of times of light emission. The first communication unit transmits the gain value to the outside.

  A camera system according to a third aspect of the present invention includes a flash device that emits flash light toward a subject, and an electronic camera to which the flash device is detachably attached.

  The flash device includes a counter, a storage unit, a gain deriving unit, and a first communication unit. The counter counts the number of flashes emitted toward the subject. The storage unit stores the number of times of light emission. The gain deriving unit derives a gain value at the current number of times of light emission based on gain information indicating a change in gain of white balance according to the number of times of light emission.

  The electronic camera includes a second communication unit and a white balance adjustment unit. The second communication unit receives the gain value from the first communication unit. The white balance adjustment unit adjusts the white balance of the image signal based on the gain value received by the second communication unit.

  In a fourth aspect based on the first aspect, the white balance adjustment unit corrects the color temperature of the flash that decreases as the number of times of light emission increases.

  In a fifth aspect based on the third aspect, the white balance adjustment unit corrects the color temperature of the flash that decreases as the number of times of light emission increases.

  According to the electronic camera of the present invention, when a built-in flash device is provided and a fixed white balance gain coefficient is used, an appropriate white balance can be adjusted even if the flash device emits more light. it can.

  According to the camera system of the present invention, it is possible to adjust the white balance appropriately even if an external flash device is attached to the electronic camera and the number of times the flash device emits light increases.

  According to the flash device of the present invention, it is possible to eliminate a decrease in color temperature that occurs due to an increase in the number of times of light emission.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an electronic camera 1 according to the first embodiment. As shown in FIG. 1, the electronic camera 1 includes a photographing lens 10, an image sensor 11, an analog front end unit (hereinafter referred to as “AFE”) 12, a signal processing unit 13, a storage unit 14, and an operation unit. 15, a CPU 16, a flash device 17, a recording medium 18, and a bus 19.

  The photographing lens 10 includes a plurality of lens groups including a zoom lens and a focus lens. For the sake of simplicity, FIG. 1 shows the photographic lens 10 as a single lens.

  The image sensor 11 generates an image signal (analog signal) by photoelectrically converting incident light from the photographing lens 10. On the image pickup surface of the image pickup element 11, three types of color filters R, G, and B are arranged in, for example, a Bayer array in order to detect the color of the subject image. Thereby, three types of pixels of the R pixel, the G pixel, and the B pixel are arranged on the imaging surface of the imaging element 11, and the image signal is composed of three types of signals of R signal, G signal, and B signal. It will be.

  The AFE 12 is an analog front end circuit that performs signal processing on an image signal generated by the image sensor 11. The AFE 12 performs gain adjustment of the image signal, A / D conversion of the image signal, and the like. Image data (digital signal) output from the AFE 12 is input to the signal processing unit 13.

  The signal processing unit 13 temporarily stores the image data output from the AFE 12 in the frame memory of the storage unit 14. Further, the signal processing unit 13 performs image processing such as white balance adjustment and gradation characteristic conversion on the image data stored in the frame memory. The storage unit 14 stores information indicating a change in white balance gain according to the number of flash emissions (irradiation) emitted from the flash light emission unit 17b toward the subject (details will be described later).

  The flash device 17 includes a flash control unit 17a and a flash light emitting unit 17b. The flash control unit 17a controls the flash emission of the flash light emitting unit 17b according to an instruction from the CPU 16. The flash light emitting unit 17b is, for example, a xenon lamp, and emits flash light toward the subject.

  The recording medium 18 is a non-volatile recording medium, and is composed of a memory card with a built-in semiconductor memory. Image data is recorded on the recording medium 18 via a recording interface (recording I / F) (not shown) according to an instruction from the CPU 16.

  The operation unit 15 is a release button, a command dial, or the like, and gives a signal to the CPU 16 in accordance with the operation content by the user. For example, the user can give a shooting instruction to the CPU 16 by fully pressing the release button.

  The CPU 16 is a processor that performs overall control of the electronic camera 1. The CPU 16 includes a counter 16a that counts the number of times the flash is emitted from the flash light emitting unit 17b. The counted value is stored in the storage unit 14. The CPU 16 also functions as a gain coefficient deriving unit 16b and a white balance (WB) adjusting unit 16c.

  When the flash emission is performed from the flash emission unit 17b, the gain coefficient deriving unit 16b is based on gain information representing a change in white balance gain according to the number of emission times, and a white balance gain coefficient (hereinafter referred to as a white balance gain coefficient) at the current number of emission times. , “Gain coefficient”).

  The white balance (WB) adjustment unit 16c adjusts the white balance of the image signal based on the gain coefficient (details will be described later). The gain coefficient is an example and may be a white balance correction amount.

  FIG. 2 is a diagram illustrating an example of the number of times of light emission and color temperature characteristics in the flash device. The horizontal axis represents the number of times of light emission, and the vertical axis represents the color temperature.

  In general, the xenon lamp of the flash light emitting portion 17b gradually decreases in color temperature due to aging deterioration caused by the number of times of light emission of the xenon lamp as the number of times of light emission increases. For easy understanding, the gain coefficient is fixed.

  In this case, as the number of times of light emission increases, an image with bluish color (high color temperature) gradually changes to an image with reddish color (low color temperature) as shown in FIG. Thus, for example, consider a case where the red (R) gain is increased by white balance processing that eliminates bluish color for a bluish image. In this case, as shown in FIG. 2, the image gradually becomes bluish to reddish according to the number of times of light emission.

  Therefore, in order to prevent the color temperature from gradually decreasing due to aging degradation caused by the number of times of light emission, the red (R) gain is set according to the decrease in the color temperature in the region where the color temperature deviates from the flat state. It becomes necessary to reduce the size and increase the blue (B) gain. In other words, in order to perform an optimal white balance process according to the number of times of light emission of the flash device, an appropriate gain coefficient must be set according to the number of times of light emission.

  FIG. 3 is a diagram illustrating an example of a relationship between the number of times of light emission in the flash device and an appropriate gain coefficient. FIG. 3A shows the relationship between the number of times of light emission and the red (R) gain coefficient. FIG. 3B shows the relationship between the number of times of light emission and the blue (B) gain coefficient. 3A and 3B is stored in advance in the storage unit 14 as, for example, a look-up table (LUT). The gain coefficient deriving unit 16b derives a gain coefficient for the current number of times of light emission based on the gain coefficient information of FIGS. 3 (a) and 3 (b). The method of deriving the gain coefficient is an example, and is not limited to this. For example, an approximate expression is stored in the storage unit 14 in advance, and the gain coefficient is obtained using the approximate expression. Also good. FIG. 3 shows, for example, the case of sunlight (sunny sky), and gain coefficient information is preliminarily stored as a look-up table (LUT) for each ambient temperature (light bulb, clear sky, cloudy sky, shade, flash device, etc.) of the shooting scene. Assume that it is stored in the storage unit 14.

  The white balance (WB) adjustment unit 16c adjusts the white balance of the image signal based on the gain coefficient at the current number of times of light emission. In this case, the white balance (WB) adjustment unit 16c corrects the color temperature of flash light emission that decreases as the number of flash light emissions increases (details will be described later).

  Next, an example of the operation of the electronic camera 1 in the first embodiment will be described.

  FIG. 4 is a flowchart showing an example of an operation until the image is recorded after being fully pressed. Here, in the following description, the electronic camera 1 measures the brightness of the subject before the full-press operation, and when the subject is dark, the flash control unit 17a is sent from the flash light emitting unit 17b at an appropriate timing according to an instruction from the CPU 16. It is assumed that a flash is irradiated toward the subject. Further, when the user selects the flash photography by manual operation, the flash control unit 17a irradiates the subject with the flash from the flash light emitting unit 17b at an appropriate timing according to an instruction from the CPU 16. It is assumed that the electronic camera 1 can determine the environmental temperature of the shooting scene before the full pressing operation by a known technique. In addition, it is assumed that an environmental temperature coefficient “a” described later is determined before the full pressing operation.

  Step S101: The CPU 16 receives the full pressing operation from the operation unit 15 (release button), and drives the image sensor 11 via a timing generator (not shown) for image acquisition. The AFE 12 performs gain adjustment of the image signal and A / D conversion of the image signal. Image data (image signal) output from the AFE 12 is input to the signal processing unit 13. The signal processing unit 13 temporarily stores the image data output from the AFE 12 in the frame memory of the storage unit 14.

  Step S102: The CPU 16 determines whether or not flash photography has been performed. If flash photography has been performed (step S102: Yes), the process proceeds to step S103.

  Step S103: The counter 16a of the CPU 16 reads the number of times of light emission stored in the storage unit 14, and adds the number of times of light emission by one.

  Step S104: The CPU 16 overwrites the storage unit 14 with the added number of times of light emission.

  Step S105: The gain coefficient deriving unit 16b of the CPU 16 refers to the look-up table stored in the storage unit 14 based on the ambient temperature of the shooting scene, and determines the red (R) gain coefficient and blue ( B) Deriving a gain coefficient.

  Step S106: When the CPU 16 issues an instruction to the signal processing unit 13, the signal processing unit 13 reads the image data temporarily stored in the frame memory of the storage unit 14.

  Step S107: The white balance (WB) adjustment unit 16c of the CPU 16 adjusts the white balance of the image signal based on the gain coefficient at the current number of times of light emission. Specifically, white balance adjustment is performed by applying the following calculation formula.

R _out = (a × K _{R ′} × R) + (1−a) × K _R × R (1)
B _out = (a × K _{B ′} × B) + (1−a) × K _B × B (2)
Here, R _out is the output value of each red (R) pixel signal after white balance adjustment. The environmental temperature coefficient a (0 ≦ a ≦ 1) is a coefficient determined according to the environmental temperature of the shooting scene (more details will be described later). K _{R ′} is a red (R) gain coefficient derived by the gain coefficient deriving unit 16b. K _R is the red (R) gain coefficient set in advance by the camera manufacturer and the like at the factory. In the present embodiment, the 1.5 K _R as an example. R is the output value (RAW data) of each red (R) pixel signal before white balance adjustment.

_Bout is the output value of each blue (B) pixel signal after white balance adjustment. K _{B ′} is a blue (B) gain coefficient derived by the gain coefficient deriving unit 16b, similarly to KR _′ . It is. K _B, like K _R, and blue (B) gain coefficient set in advance by the camera manufacturer and the like at the factory. In the present embodiment, the 0.8 K _B as an example. B is the output value (RAW data) of each blue (B) pixel signal before white balance adjustment.

  In both formulas (1) and (2), the first term is applied when the ambient temperature of the shooting scene is flash photography, and the second term is the ambient temperature of the shooting scene such as a light bulb, clear sky, cloudy sky, shade, etc. Applies to

  FIG. 5 is a diagram illustrating an example of the relationship between the environmental temperature coefficient of the shooting scene and the brightness. The horizontal axis represents the degree of brightness, and the vertical axis represents the value of the environmental temperature coefficient a.

For example, when flash photography is performed under dark conditions where the second term can be ignored, the value of the environmental temperature coefficient a is 1. Then, equation (1) becomes
R _out = (a × K _{R ′} × R) (3)
Similarly, equation (2) is
B _out = (a × K _{B ′} × B) (4)

When flash photography is not necessary under bright conditions, the value of the environmental temperature coefficient a is zero. Then, equation (1) becomes
R _out = K _R × R (5)
Similarly, equation (2) is
B _out = K _B × B (6)

  As described above, it is assumed that the range of the environmental temperature coefficient a is 0 ≦ a ≦ 1, and is predetermined by the environmental temperature of the shooting scene.

  Therefore, the white balance (WB) adjustment unit 16c can set the environmental temperature coefficient a according to the environmental temperature of the shooting scene. The method for obtaining the ambient temperature of the shooting scene can be obtained by a known method.

  Here, 0 <a because the process is performed when flash photography is performed in step S102 (step S102: Yes). When the white balance is adjusted by the white balance (WB) adjustment unit 16c, the process proceeds to step S108.

  Step S108: Upon receiving an instruction from the CPU 16, the signal processing unit 13 performs gradation characteristic conversion such as a known gamma (γ) conversion process according to the gradation characteristic on the RGB image data subjected to white balance adjustment. I do.

  Step S109: In response to an instruction from the CPU 16, the signal processing unit 13 converts the format of the RGB image data subjected to the gradation characteristic conversion into a luminance signal and a color difference signal.

  Step S110: The CPU 16 performs compression processing on the format-converted image data (luminance signal, color difference signal).

  Step S111: The CPU 16 records the format-converted image data on the recording medium 18. Then, this processing routine ends.

  Next, a case where flash photography has not been performed in step S102 (step S102: No) will be described. In this case, the process routine proceeds to step S112.

  Step S112: Since the flash photography was not performed, the CPU 16 sets the environmental temperature coefficient a to 0. In this case, the above equations (5) and (6) are derived. Then, the process proceeds to step S106.

  Step S106: The CPU 16 issues an instruction to the signal processing unit 13, so that the signal processing unit 13 reads the image data temporarily stored in the frame memory of the storage unit 14.

  Step S107: The white balance (WB) adjustment unit 16c of the CPU 16 adjusts the white balance of the image signal based on the gain coefficient at the current number of times of light emission. Specifically, white balance adjustment is performed by applying the above equations (5) and (6). Then, the process proceeds to step S108. Since the processing after step S108 is the same as that in the case of flash photography, description thereof will be omitted. This processing routine is completed.

  As described above, according to the electronic camera 1 of the first embodiment, when a fixed gain coefficient is used, the gain coefficient deriving unit 16b can be used even if the color temperature decreases due to an increase in the number of times the built-in flash device 17 emits light. Derives a gain coefficient in accordance with the number of times of light emission, and the white balance (WB) adjustment unit 16c can perform appropriate white balance adjustment based on the gain coefficient. As a result, the user can obtain an image on which appropriate white balance adjustment has been performed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment of the present invention and the second embodiment of the present invention, the same elements are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, a camera system including an external flash device and an electronic camera will be described.

  First, the configuration of the electronic camera 2 will be described, and then the configuration of the external flash device 3 will be described.

  FIG. 6 is a block diagram showing the configuration of the camera system in the second embodiment. As shown in FIG. 6, the electronic camera 2 includes a photographing lens 10, an image sensor 11, an AFE 12, a signal processing unit 13, a storage unit 14, an operation unit 15, a CPU 16, a recording medium 18, and a bus 19. And a second communication unit 20.

  The difference between the electronic camera 1 of the first embodiment and the electronic camera 2 of the second embodiment is that the electronic camera 1 has a built-in flash device 17, whereas the electronic camera 2 has an external flash device 3 attached and detached. It can be freely attached to the electronic camera body. Therefore, the electronic camera 2 is newly provided with a second communication unit 20. The second communication unit 20 is an interface that communicates with the flash device 3. Here, when the external flash device 3 is attached to the electronic camera 2, it is electrically connected. Thereby, communication is enabled between the second communication unit 20 of the electronic camera 2 and the first communication unit 33 of the flash device 3 described later.

  Further, the CPU 16 of the electronic camera 1 of the first embodiment is provided with a counter 16a, but the CPU 16 of the electronic camera 2 of the second embodiment is not provided with a counter 16a. This is because the flash device 3 counts the number of times of light emission (details will be described later).

  Next, the configuration of the external flash device 3 will be described.

  The flash device 3 shown in FIG. 6 includes a flash light emitting unit 31, a flash control unit 32, a first communication unit 33, and a storage unit 34. The flash light emission part 31 is a xenon lamp like the flash light emission part 17b shown in FIG.

  The flash control unit 32 controls the flash emission of the flash light emitting unit 31 according to an instruction from the CPU 16 of the electronic camera 2. The flash control unit 32 includes a counter 32a and a gain coefficient deriving unit 32b. The counter 32a softly counts the number of times the flash light is emitted from the flash light emitting unit 31. When the flash light emission is performed from the flash light emission unit 31, the gain coefficient deriving unit 32b derives the gain coefficient at the current number of light emission based on the gain information as in the electronic camera 1 of the first embodiment.

  The first communication unit 33 is a communication interface that communicates with the electronic camera 2 and transmits a gain coefficient to the second communication unit 20 of the electronic camera 2 as described later. Note that not only the gain coefficient data but also information such as command instructions are exchanged between the first communication unit 33 and the second communication unit 20 through the communication interface.

  The storage unit 34 is a non-volatile memory and stores gain information. In addition, as described above, the storage unit 34 stores the number of times of light emission.

  Next, the operation of the camera system will be described.

  FIG. 7 is a flowchart showing an example of an operation until the image is recorded after being fully pressed. The preconditions before the full pressing operation are the same as those in the first embodiment.

  Step S201: The CPU 16 drives the image sensor 11 in response to a full pressing operation from the operation unit 15 (release button). The AFE 12 performs gain adjustment of the image signal and A / D conversion of the image signal. Image data (image signal) output from the AFE 12 is input to the signal processing unit 13. The signal processing unit 13 temporarily stores the image data output from the AFE 12 in the frame memory of the storage unit 14.

  Step S202: The CPU 16 determines whether or not flash photography has been performed. If flash photography has been performed (step S202: Yes), the process proceeds to step S203.

  Step S203: The CPU 16 issues an instruction to the flash control unit 32 via the first communication unit 33 and the second communication unit 20, so that the counter 32a of the flash control unit 32 obtains the previous light emission count from the storage unit 34. Read and add one time.

  Step S204: The CPU 16 issues an instruction to the flash control unit 32, whereby the flash control unit 32 overwrites the number of times of light emission added to the storage unit 34.

  Step S205: The CPU 16 issues an instruction to the flash control unit 32, so that the gain coefficient deriving unit 32b of the flash control unit 32 uses the lookup table stored in the storage unit 14 based on the environmental temperature of the shooting scene. The red (R) gain coefficient and the blue (B) gain coefficient at the current number of times of light emission are derived.

  Step S <b> 206: The CPU 16 sends an instruction to the flash control unit 32, so that the flash control unit 32 transmits the gain coefficient value from the first communication unit 33 to the second communication unit 20.

  Step S207: When the second communication unit 20 receives the gain coefficient, the CPU 16 reads the gain coefficient.

  Step S208: The CPU 16 issues an instruction to the signal processing unit 13, so that the signal processing unit 13 reads the image data temporarily stored in the frame memory of the storage unit 14.

  Step S209: The white balance (WB) adjustment unit 16c of the CPU 16 adjusts the white balance of the image signal based on the gain coefficient at the current number of times of light emission. When the white balance is adjusted by the white balance (WB) adjustment unit 16c, the process proceeds to step S210. Subsequent processing (step S210 to step S213) is the same as the processing (step S108 to step S111) shown in FIG. Then, this processing routine ends.

  Next, the case where flash photography has not been performed in step S202 (step S202: No) will be described. In this case, the process routine proceeds to step S214.

  Step S214: Since the flash photography has not been performed, the CPU 16 sets the environmental temperature coefficient a to 0. In this case, the above equations (5) and (6) are derived. Then, the process proceeds to step S208.

  Step S208: The CPU 16 issues an instruction to the signal processing unit 13, so that the signal processing unit 13 reads the image data temporarily stored in the frame memory of the storage unit 14.

  Step S209: The white balance (WB) adjustment unit 16c of the CPU 16 adjusts the white balance of the image signal based on the gain coefficient at the current number of times of light emission. Specifically, white balance adjustment is performed by applying the above equations (5) and (6). Then, the process proceeds to step S210. Since the processing after step S210 is the same as that in the case of flash photography, description thereof will be omitted. This processing routine is completed.

  As described above, according to the camera system of the second embodiment, the flash device 3 derives a gain coefficient according to the number of times of light emission and transmits it to the electronic camera 2, and the white balance (WB) adjustment unit 16c of the electronic camera 2 gains the gain coefficient. Adjust the white balance based on. As a result, the external flash device 3 can cause the electronic camera 2 to eliminate the decrease in the color temperature caused by the increase in the number of times of light emission. Therefore, the electronic camera 2 can adjust the white balance appropriately even if the flash device 3 emits more light. As a result, the user can obtain an image on which appropriate white balance adjustment has been performed.

  As described above, according to the first embodiment and the second embodiment, when irradiation of the flash devices 17 and 3 is dominant in a low-brightness environment (when it is determined that the image is dark in a live display state called a through image). Are affected by the flash devices 17 and 3. In the first embodiment and the second embodiment, in such a case (environmental temperature coefficient a = 1 or the like), the gain coefficient can be derived from the number of times the flash devices 17 and 3 emit light, thereby simplifying the white balance processing. be able to.

Further, when shooting is performed with the flash devices 17 and 3 in a dark environment, in the first and second embodiments, even if the gain coefficient is fixed, the influence of a decrease in color temperature due to an increase in the number of times of light emission is exerted. You do n’t have to. Accordingly, it is possible to provide an electronic camera and a camera system that can keep an appropriate white balance.
<Supplementary items of the embodiment>
In the first embodiment and the second embodiment, the number of times of light emission is used as a guideline for deriving the gain coefficient, but the amount of energy consumed for light emission of the xenon tubes used in the flash devices 17 and 3 is accumulated, The integrated amount may be used as a guide for deriving the gain coefficient.

1 is a block diagram illustrating a configuration of an electronic camera 1 according to a first embodiment. An example of the number of light emission and color temperature characteristics in a flash device Figure showing an example of the relationship between the number of flashes and the appropriate gain coefficient in the flash device Flowchart showing an example of the operation until the image is recorded after being fully pressed The figure which shows an example of the relationship between the environmental temperature coefficient of a photography scene, and brightness The block diagram which shows the structure of the camera system in 2nd Embodiment. Flowchart showing an example of the operation until the image is recorded after being fully pressed

Explanation of symbols

1, 2 ... Electronic camera, 3, 17 ... Flash device, 16a, 32a ... Counter, 16b, 32b ... Gain coefficient deriving unit, 16c ... WB adjusting unit, 14, 34 ... -Storage part, 33 ... 1st communication part, 20 ... 2nd communication part

Claims (5)

An image sensor that images a subject and generates an image signal;
A flash light emitting part for emitting a flash on the subject;
A counter that counts the number of times of light emission of the flash light emitting unit;
A storage unit for storing the number of times of light emission;
A gain deriving unit for deriving a gain value at the current number of times of light emission based on gain information representing a change in gain of white balance according to the number of times of light emission when flash light emission is performed from the flash light emitting unit;
A white balance adjustment unit that adjusts a white balance of the image signal based on the gain value;
An electronic camera comprising: A counter that counts the number of flashes emitted toward the subject;
A storage unit for storing the number of times of light emission;
A gain deriving unit for deriving a gain value at the current number of times of light emission based on gain information representing a change in gain of white balance in accordance with the number of times of light emission;
A first communication unit for transmitting the gain value to the outside;
A flash device comprising: A camera system comprising: a flash device that emits a flash toward a subject; and an electronic camera to which the flash device is detachably attached,
The flash device is
A counter that counts the number of flashes emitted toward the subject;
A storage unit for storing the number of times of light emission;
A gain deriving unit for deriving a gain value at the current number of times of light emission based on gain information representing a change in gain of white balance in accordance with the number of times of light emission;
A first communication unit for transmitting the gain value to the outside;
Have
The electronic camera is
A second communication unit that receives the gain value from the first communication unit;
A white balance adjustment unit that adjusts a white balance of the image signal based on the gain value received by the second communication unit;
A camera system comprising: The electronic camera according to claim 1,
The electronic camera according to claim 1, wherein the white balance adjustment unit corrects a color temperature of the flash that decreases as the number of times of light emission increases. The camera system according to claim 3.
2. The camera system according to claim 1, wherein the white balance adjustment unit corrects the color temperature of the flash that decreases as the number of times of light emission increases.

Images