JP2003102019A - White balance adjustment device and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white balance adjustment device capable of properly performing white balance adjustment for an image signal even in the case of using a color filter so as to photograph an image of an object and to provide a camera system. SOLUTION: The camera system 10 is provided with a detection means 24 for detecting whether or not a color filter (13 or 14) is inserted to at least one optical path for an illumination luminous flux leading to an object and an incident luminous flux from the object to an imaging device 31, and an adjustment means 34 for adjusting the white balance of an image signal obtained from the imaging element by taking a result of the detection by the detection means into account.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white balance adjusting device and a camera system for adjusting the white balance of an image signal.

[0002]

2. Description of the Related Art Conventionally, there is known a device for adjusting the white balance of an image signal (a plurality of color signals) obtained by picking up an image of a subject. The image signals (plurality of color signals) to be subjected to white balance adjustment are generally three primary color signals of a red signal, a green signal and a blue signal. The white balance adjusting device is incorporated in an electronic camera such as a digital still camera or a digital video camera.

The adjustment of white balance in an electronic camera is usually performed in order to obtain a photograph having a natural color tone close to the appearance. Therefore, when the light source that illuminates the subject is sunlight, fluorescent light, light bulb, or other light source, the amplification gain for the image signal (three primary color signals) is changed according to the color temperature of the light source, and the changed amplification gain Is used to adjust the white balance. As a result, even if the color temperature of the light source is different, it is possible to always obtain a photograph having almost the same color tone.

In general, to change the amplification gain according to the color temperature of the light source, a plurality of types of amplification gains stored in advance in the apparatus are used, and one of them is selected according to the color temperature of the light source. It is executed by reading it out. Also, in the method in which the color temperature of the subject (that is, the color temperature of the light source) is measured before shooting with the electronic camera and the amplification gain is calculated according to the obtained color temperature, the amplification gain is changed based on the calculation result. can do.

By the way, the above-mentioned light sources (sunlight, fluorescent lamps,
In a dark place where the amount of light (such as a light bulb) is insufficient,
Usually, a subject is supplementarily illuminated by using a flash of light emitted from a flash light emitting device (artificial light source), and an image is taken by an electronic camera. Further, such white balance adjustment during flash photography is performed by using an amplification gain according to the color temperature of the flash light emitting device among a plurality of types of amplification gains stored in advance in the device. Therefore, even during flash photography,
It is possible to obtain a photograph with a natural color tone close to the appearance.

[0006]

However, in the above-mentioned conventional white balance adjusting device, when the flash light emitting device is equipped with the color filter, the white balance adjustment at the time of flash photographing cannot be properly performed, and the white balance adjusting device cannot be performed. Sometimes the image looks unnatural with a color tone different from the person's intention.

This is because the color temperature of the flash light emitting device itself (when the color filter is not attached, the flash light emitted from the flash light emitting device and transmitted through the color filter is irradiated to the subject as illumination light). This is because the white balance of the image signal (three primary color signals) is adjusted by using the amplification gain according to the color temperature of the flash light. Further, the problem as described above is not limited to the case where the color filter is inserted in the optical path of the flash emitted from the flash light emitting device, and the color filter is inserted in the optical path of the light (object light) incident on the image pickup element from the subject. In some cases, this may also occur, resulting in an unnatural photograph with a color tone different from the photographer's intention.

An object of the present invention is to provide a white balance adjusting device and a camera system which can properly perform white balance adjustment of an image signal even when an image of a subject is picked up by using color filters.

[0009]

A white balance adjusting apparatus according to claim 1, wherein a color filter is inserted in at least one optical path of an illumination light flux to the subject and an incident light flux from the subject to the image pickup device. It is provided with a detecting means for detecting whether or not there is any, and an adjusting means for adjusting the white balance of the image signal obtained from the image pickup device in consideration of the detection result by the detecting means.

A white balance adjusting device according to a second aspect is the white balance adjusting device according to the first aspect, wherein the detecting means is inserted into the optical path when the color filter is inserted into the optical path. The color characteristic of the color filter is detected, the adjusting unit calculates a white balance adjustment amount in consideration of the color characteristic detected by the detecting unit, and the image signal of the image signal is calculated based on the white balance adjustment amount. It adjusts the white balance.

According to a third aspect of the present invention, there is provided an electronic device having the white balance adjusting device according to the first or second aspect, the flash light emitting device for emitting the illumination luminous flux as a flash light, and the image pickup device. A camera system including a camera body, wherein the flash light emitting device has a mounting portion of the color filter in the vicinity of a portion from which the illumination light flux is emitted, and the detecting unit includes the color filter in the mounting portion. Whether or not the color filter is mounted on the optical path is detected based on whether or not the filter is mounted.

A white balance adjusting device according to a fourth aspect is the camera system according to the third aspect, wherein the flash light emitting device and the electronic camera body are detachable, and the detecting means is the flash light emitting device. And the adjusting means is provided inside the electronic camera body, and further comprises communication means for transmitting the detection result of the detecting means to the adjusting means.

According to a fifth aspect of the present invention, there is provided a white balance adjusting device, wherein the white balance adjusting device according to the first or second aspect, a photographing lens for guiding the incident light flux from the subject to the image pickup device, and the image pickup device. A camera system including an electronic camera body having an element, wherein the taking lens is near a portion that takes in the incident light flux,
And a detection unit that detects whether or not the color filter is attached to the optical path, based on whether or not the color filter is attached to the attachment unit. is there.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. (First Embodiment) A first embodiment of the present invention corresponds to claims 1 to 4. Camera system 10 of the first embodiment
As shown in FIG. 1, is composed of a flash light emitting device 11 and an electronic camera 12, and the electronic camera 12 includes a taking lens 12
It is composed of a and a body 12b. Electronic camera 12
Is a digital still camera. Further, a white balance adjusting device 10a, which will be described later, is provided inside the camera system 10. In this camera system 10, a flash light emitting device 11 and a body 12 of an electronic camera 12
b is detachable.

Further, the flash light emitting device 11 of the camera system 10 accommodates two color filters 13 and 14. However, each of the two color filters 13 and 14 can be drawn out of the flash light emitting device 11. And
The flash light emitting device 11 has a mounting portion 11a for mounting one color filter (13 or 14) pulled out to the outside.
Is provided. The mounting portion 11a is provided with the flash light emitting device 11
Is located in the vicinity of the part that emits the illumination light flux (flash) to the subject.

The two color filters 13 and 14 are pulled out one by one according to the photographer's intention and mounted on the mounting portion 11a of the flash light emitting device 11. The color filter 13 or the color filter 14 is attached to the attachment portion 11a.
Is inserted in the optical path of the luminous flux (flash) to the subject. Here, the one color filter 13 is an optical element having a color characteristic that mainly transmits light in the green wavelength range (500 nm to 600 nm). The other color filter 14 has an orange (amber) wavelength range (600 n
(m to 700 nm) is an optical element having color characteristics that mainly transmit light.

Next, the flash light emitting device 11 and the electronic camera 12
The internal configuration of the camera system 10 configured as will be specifically described with reference to FIG. FIG. 2 shows a state in which the color filter 13 is attached to the attachment portion 11a (not shown) of the flash light emitting device 11 and is inserted in the optical path L1 of the illumination light flux (flash light) to the subject. Now, in addition to the color filters 13 and 14 described above, the flash light emitting device 11 includes a light emitting section 21.
A light emission control circuit 22, a switch 23, a color filter identification circuit 24 (corresponding to "detection means" in claims), and a communication circuit 25 are provided.

In the electronic camera 12, in addition to the photographing lens 12a described above, an image pickup device 31 and an ambient light photometric circuit 32 are provided.
Ambient light colorimetric circuit 33, adjusting circuit 34 (corresponding to "adjusting means" in claims), recording circuit 35, and communication circuit 3
And 6 are provided. The components (31 to 36) other than the taking lens 12a in the electronic camera 12 are the body 1
It is provided inside 2b (FIG. 1).

The respective constituent elements (21 to 25, 31 to 36) provided in the camera system 10 will be individually described below. The communication circuit 25 of the flash light emitting device 11 and the communication circuit 36 of the electronic camera 12 are circuits for performing communication (transmission of information) between the flash light emitting device 11 and the body 12b (FIG. 1) of the electronic camera 12. is there. Communication circuit 25,36
Corresponds to "communication means" in the claims.

The information transmitted via the communication circuits 25 and 36 includes, for example, information from the color filter identification circuit 24 of the flash light emitting device 11 to the adjustment circuit 34 of the electronic camera 12 (color filter signals described later), There is information (flash light amount signal described later) from the light emission control circuit 22 of the flash light emitting device 11 to the adjustment circuit 34 of the electronic camera 12. The light emitting unit 21 of the flash light emitting device 11 is a xenon lamp that emits an illumination light flux (flash light) to the subject. The spectral characteristic (spectrum) of the flash light emitted from the light emitting section 21 has a peak in the blue wavelength range (400 nm to 500 nm) as shown in FIG.

Incidentally, the mounting portion 11 of the flash light emitting device 11
When the color filter 13 is attached to a (FIG. 1) (state of FIG. 2), the color filter 13 has a wavelength range (500 nm to 600 n).
m) has a color characteristic of mainly transmitting the light, the spectral characteristic of the flash light after passing through the color filter 13 has a peak in the wavelength range of blue-green (near 500 nm) as shown in FIG. become. That is, the color temperature of the flash light emitted from the light emitting unit 21 (FIG. 3) is converted into the color temperature of the fluorescent lamp (FIG. 4) by using the color filter 13.

When the color filter 14 is mounted on the mounting portion 11a in place of the color filter 13, the color filter 14
Has a color characteristic of mainly transmitting light in the wavelength range (600 nm to 700 nm), the spectral characteristic of the flash light after passing through the color filter 14 is, as shown in FIG. 5, an orange (amber) wavelength. It will have a peak in the region (around 600 nm). That is, the color temperature of the flash light emitted from the light emitting unit 21 (FIG. 3) is converted into the color temperature of the electric bulb (FIG. 5) by using the color filter 14.

In addition, the color filter identification circuit 24 of the flash light emitting device 11 (FIG. 2) is the mounting portion 1 for the color filters 13 and 14.
It is a switch that is turned on / off according to the mounting state on the 1a (FIG. 1). The color filter identification circuit 24 can detect whether or not the color filter (13 or 14) is attached to the attachment portion 11a (that is, whether or not the color filter is inserted in the optical path L1 of the flash light).

Further, according to the color filter identifying circuit 24, when the color filter (13 or 14) is mounted on the mounting portion 11a (that is, inserted into the optical path L1), the color filter (13 or 14) is detected. It is also possible to detect the color characteristic, that is, which of the two color filters (13 or 14) is attached (inserted). Therefore, the color filter signal indicating the detection result by the color filter identification circuit 24 includes a signal indicating that the color filter 13 is attached (inserted) and a signal indicating that the color filter 14 is attached (inserted), There are three types of signals, that is, a signal indicating that neither the color filter 13 nor the color filter 14 is attached (inserted).

The color filter signal (any one of the above three types) indicating the detection result by the color filter identification circuit 24 is transmitted through the communication circuits 25 and 36 to the adjustment circuit 34 of the electronic camera 12.
Be transmitted to. The color filter identifying circuit 24 and the adjusting circuit 34 (details of which will be described later) constitute a white balance adjusting device 10a shown by a dotted line in FIG. The switch 23 of the flash light emitting device 11 is a switch for selecting whether or not to perform flash photography and a mode such as a guide number at the time of flash photography, and is operated according to the intention of the photographer.
The flash photography mode signal obtained from the switch 23 is output to the light emission control circuit 22.

The light emission control circuit 22 is a circuit for controlling the light emission of the light emitting section 21 by the external automatic light control system when the flash photography mode signal obtained from the switch 23 indicates "perform flash photography". A photometric sensor (not shown) used in an external automatic light control system is provided in the light emission control circuit 22. That is, the light emission control circuit 22 includes an internal photometric sensor.
(Not shown), the amount of flash light reflected from the subject is detected in real time, and when the amount of flash light reaches a predetermined fixed amount (appropriate light amount) End the emission of the flash of.

Then, the light emission control circuit 22 outputs information (flash light amount signal) relating to the light amount (guide number) of the flash light actually emitted from the light emitting section 21. The flash light amount signal from the light emission control circuit 22 is transmitted to the adjustment circuit 34 of the electronic camera 12 via the communication circuits 25 and 36. As described above, when the subject is irradiated with flash light from the light emitting unit 21 of the flash light emitting device 11, the incident light flux (subject light flux) from the subject to the electronic camera 12 is generally due to the flash light (artificial light). The light flux generated from the subject by the illumination and the light flux generated by the subject by the illumination by the ambient light (natural light) such as sunlight, fluorescent lamps, and electric bulbs are included.

Here, it can be considered that the light quantity ratio between the subject light flux due to the flash light and the subject light flux due to the ambient light is almost equal to the light quantity ratio between the flash light and the ambient light. The light quantity of the flash light (flash light quantity signal) detected by the drawing) and the peripheral light photometric circuit 32 described later.
It can be calculated based on the ratio with the light amount of the ambient light detected by (peripheral light signal).

Then, the incident light flux (subject light flux) on the electronic camera 12 passes through the photographing lens 12a and the image pickup device 3
1 is incident on the image pickup surface. An image of a subject is formed on the image pickup surface of the image pickup device 31. The image pickup device 31 is the photographing lens 1.
A two-dimensional image sensor that captures an image of a subject formed by 2a, and outputs an image signal (three primary color signals of a red signal, a green signal, and a blue signal) obtained by capturing an image of the subject to the adjustment circuit 34. . Each color signal of the image signal represents the strength of each color component of the subject light flux.

The ambient light photometric circuit 32 is a photometric sensor for measuring the light intensity (luminance) of ambient light (sunlight, fluorescent lamps, light bulbs, etc.) of the subject, and an adjustment circuit for the ambient light intensity signal indicating the measurement result. To 34. The ambient light colorimetric circuit 33
It is a colorimetric sensor that measures the color temperature (spectral characteristics) of ambient light, and outputs an ambient light color temperature signal indicating the measurement result to the adjustment circuit 34. When the ambient light is a fluorescent lamp, the spectral characteristic indicated by the ambient light color temperature signal has a peak in the wavelength range of blue-green (near 500 nm) as shown in FIG.
The measurement by the ambient light photometric circuit 32 and the ambient light colorimetric circuit 33 is performed via the taking lens 12a.

The adjusting circuit 34 includes a color filter signal from the color filter identifying circuit 24, a flash light intensity signal from the emission control circuit 22, a peripheral light intensity signal from the ambient light photometric circuit 32, and an ambient light colorimetric signal. This circuit adjusts the white balance of the image signal (three primary color signals) obtained from the image pickup device 31 in consideration of the ambient light color temperature signal from the circuit 33. The adjustment circuit 34 includes a memory 41, a reference circuit 42,
It is composed of a white balance calculation circuit 43 and a signal processing circuit 44.

Of these, in the memory 41, the white balance adjustment amount according to the spectral characteristic of the flash itself emitted from the light emitting section 21 (FIG. 3) and the spectral characteristic of the flash after passing through the color filter 13 (see FIG. The white balance adjustment amount according to 4) and the white balance adjustment amount according to the spectral characteristic (FIG. 5) of the flash light after passing through the color filter 14 are stored.

The three types of white balance adjustment amounts in the memory 41 are the red wavelength range (600 nm to 700 nm) and the green wavelength range in the respective spectral characteristics (FIGS. 3 to 5).
(500nm-600nm) and blue wavelength range (400nm
(-500 nm) is an amplification gain determined so that the spectral intensities thereof are equal to each other. Further, in the memory 41, the three types of white balance adjustment amounts are respectively set in the mounting portions 11a of the color filters 13 and 14.
It is stored as a table in association with the mounting state (that is, the state of inserting the flash light into the optical path L1) to (FIG. 1).

That is, (1) the white balance adjustment amount corresponding to the spectral characteristic (FIG. 3) of the flash itself emitted from the light emitting section 21 is associated with the state in which the color filters 13 and 14 are not attached (inserted). The (2) white balance adjustment amount according to the spectral characteristic (FIG. 4) of the flash light after passing through the color filter 13 is associated with the state in which the color filter 13 is attached (inserted), and the (3) color The white balance adjustment amount according to the spectral characteristic of the flash light after passing through the filter 14 (FIG. 5) is associated with the state in which the color filter 14 is attached (inserted).

The reference circuit 42 is a color filter identification circuit 24.
The color filter signal from is input, and the table in the memory 41 is referred to based on this color filter signal. As described above, the color filter signal is attached to the color filter 13.
A signal indicating (inserted) and the color filter 14 are attached.
It is either a signal indicating (inserted) or a signal indicating that neither the color filter 13 nor the color filter 14 is attached (inserted).

Then, the reference circuit 42 reads out one white balance adjustment amount corresponding to the color filter signal (one of the above three types) from the three types of white balance adjustment amounts in the memory 41, and calculates the white balance. Circuit 4
Output to 3. For example, as shown in FIG.
When 3 is attached (inserted), the reference circuit 42 reads the white balance adjustment amount according to the spectral characteristic (FIG. 4) of the flash light after passing through the color filter 13 and outputs it to the white balance calculation circuit 43. To do.

The white balance calculation circuit 43 includes
In addition to the white balance adjustment amount related to the flash light being input from the reference circuit 42, the flash light amount signal is input from the emission control circuit 22, the ambient light amount signal is input from the ambient light photometric circuit 32, and the ambient light colorimetric circuit 33 is input. The ambient light color temperature signal is input. Then, the white balance calculation circuit 43 first calculates the white balance adjustment amount related to the ambient light based on the ambient light color temperature signal from the ambient light colorimetric circuit 32. The white balance adjustment amount related to the ambient light is an amplification gain (gain) determined so that the red, green, and blue output signals are equal to each other in the spectral characteristic of the ambient light (for example, FIG. 6).

Further, the white balance calculation circuit 43 calculates the light quantity ratio between the flash light and the peripheral light based on the flash light quantity signal from the light emission control circuit 22 and the peripheral light quantity signal from the peripheral light photometry circuit 32. As described above, the light quantity ratio between the flash light and the ambient light represents the light quantity ratio between the subject light flux due to the flash light and the subject light flux due to the peripheral light in the subject light flux incident on the image sensor 31.

In this way, when the white balance adjustment amount relating to the flash light, the white balance adjustment amount relating to the ambient light, and the light amount ratio of the flash light to the ambient light are obtained, next,
The white balance calculation circuit 43 calculates a white balance adjustment amount required for white balance adjustment for an actual image signal (three primary color signals). That is, the white balance adjustment amount related to the flash light and the white balance adjustment amount related to the ambient light are added for each color according to the light amount ratio of the flash light to the ambient light, and the white balance adjustment amount required for the actual white balance adjustment is added. To calculate.

For example, the light amount ratio of the flash light to the ambient light at the object position is La: Lb, the white balance adjustment amount related to the flash light is the amplification gain Ra for the red signal, and the white balance adjustment amount related to the ambient light is If the amplification gain for the red signal is Rb, the amplification gain for the red signal out of the white balance adjustment amount required for the actual white balance adjustment is calculated from the relational expression of La · Ra + Lb · Rb.
The same applies to other color signals.

The white balance adjustment amount required for the actual white balance adjustment calculated by the white balance calculation circuit 43 is output to the signal processing circuit 44 in the subsequent stage. The signal processing circuit 44 is a circuit that actually performs white balance adjustment based on the white balance adjustment amount calculated by the white balance calculation circuit 43. An image signal (three primary color signals) obtained from the image sensor 31 is input to the signal processing circuit 44.

The white balance adjustment in the signal processing circuit 44 is the amplification gain for the red signal (corresponding to La.Ra + Lb.Rb in the above example) of the white balance adjustment amount calculated by the white balance calculation circuit 43.
Is multiplied by the red signal of the image signal, the amplification gain for the green signal is multiplied by the green signal of the image signal, and the amplification gain for the blue signal is multiplied by the blue signal of the image signal.

In the signal processing circuit 44, in addition to the above white balance adjustment, gamma processing, color conversion processing,
Image processing such as color correction processing and interpolation processing is also performed. In the signal processing circuit 44, when the white balance adjustment and various kinds of image processing for the image signal (three primary color signals) are completed, the processed image signal (three primary color signals) is recorded in the recording circuit 35.
Output to. The recording circuit 35 records the image signal (three primary color signals) from the signal processing circuit 44 on a recording medium.

As described above, in the camera system 10 according to the first embodiment, the white balance adjustment amount is adjusted in consideration of the detection result of the color filter identification circuit 24 and the color characteristics of the color filter (13 or 14). The white balance of the image signal (three primary color signals) obtained from the image sensor 31 is adjusted based on the calculated and obtained white balance adjustment amount. Therefore, even when the image of the subject is captured using the color filter (13 or 14), proper white balance adjustment can be automatically performed, and a photograph with a color tone that reflects the intention of the photographer can be obtained. it can.

Although the camera system 10 of the first embodiment described above is provided with the ambient light photometric circuit 32 and the ambient light colorimetric circuit 33 independently in order to measure the amount of ambient light and the color temperature of the subject. The present invention can also be applied to a camera system 50 in which the ambient light photometric circuit 32 and the ambient light colorimetric circuit 33 are omitted as shown in FIG. In this case, the signal processing circuit 51 measures the light amount and the color temperature of the ambient light of the subject based on the image signal obtained from the image sensor 31. Therefore, the ambient light amount signal and the ambient light color temperature signal similar to those in the first embodiment are output from the signal processing circuit 51 to the adjustment circuit 34.

Furthermore, the camera system 1 of the first embodiment.
With 0, when calculating the white balance adjustment amount during flash photography, both the white balance adjustment amount related to the flash light and the white balance adjustment amount related to the ambient light are used and added according to the light amount ratio between the flash light and the ambient light. However, the present invention is not limited to this configuration.

Generally, the purpose of inserting the color filters (13, 14) into the optical path L1 of the flash light is to match the color temperature of the flash light for auxiliary illumination of the object with the color temperature of the ambient light of the object. In this case, the color temperature within one screen is almost uniform. For example, when the ambient light of the subject is a fluorescent lamp, the color temperature of the ambient light is as shown in FIG.
It has a peak in the wavelength range of blue-green (around 500 nm). At this time, if the color filter 14 is inserted in the optical path L1 of the flash light,
The color temperature of the flash light after passing through the color filter 14 also has a peak in the wavelength range of blue-green (near 500 nm) as in the spectral characteristic shown in FIG. 5, so that the color temperature within one screen is substantially uniform. Become.

Therefore, when determining the white balance adjustment amount for flash photography, it is appropriate to determine based on only the white balance adjustment amount for the flash light without using the white balance adjustment amount for the ambient light. The white balance can be automatically adjusted, and a photograph with a color tone that reflects the photographer's intention can be obtained. In the camera system 10 of the first embodiment described above, the memory 41 of the adjustment circuit 34 is set so that the spectral intensities of the red, green, and blue wavelength ranges of the spectral characteristics (FIGS. 3 to 5) are equal to each other. Although the obtained amplification gain is stored, the present invention is not limited to this.

In the memory 41 of the adjusting circuit 34, for example,
The spectral characteristics (FIGS. 3 to 5) themselves may be stored, or the color characteristics of the color filters 13 and 14 (transmittance characteristics, absorptance characteristics, etc.) may be stored. When the spectral characteristics (FIGS. 3 to 5) are stored in the memory 41, the reference circuit 42 reads out one spectral characteristic from the memory 41 based on the color filter signal from the color filter identification circuit 24, and white balance The circuit outputs to the arithmetic circuit 43. The white balance calculation circuit 43 calculates the amplification gain based on the spectral characteristic obtained from the reference circuit 42 so that the spectral intensities in the red, green and blue wavelength ranges are equal to each other.
Using this, it becomes a circuit for calculating the white balance adjustment amount during the actual white balance adjustment.

Further, the color filters 13, 14 are stored in the memory 41.
When storing the color characteristics of the
It is also preferable to store the spectral characteristics (FIG. 3) of the flash light itself emitted from the device. In this case, the reference circuit 42
When the color filter signal from the color filter identification circuit 24 indicates “non-attachment of the color filters 13 and 14”, only the spectral characteristic (FIG. 3) is read from the memory 41 and output to the white balance calculation circuit 43. Then, the white balance calculation circuit 43 calculates the amplification gain based on the spectral characteristic (FIG. 3), and uses this to calculate the white balance adjustment amount necessary for the actual adjustment.

Further, when the color filter signal from the color filter identifying circuit 24 indicates "mounting of the color filter (13 or 14)", the reference circuit 42 determines from the memory 41 the color characteristics of the color filter (13 or 14). The spectral characteristics (FIG. 3) are read and output to the white balance calculation circuit 43.
Then, the white balance calculation circuit 43 calculates the spectral characteristic (FIG. 4 or 5) of the flash light after passing through the color filter (13 or 14) based on the color characteristic and the spectral characteristic (FIG. 3), and obtains it. The amplification gain is calculated based on the obtained spectral characteristics, and using this, the white balance adjustment amount required for actual adjustment is calculated.

Further, in the camera system 10 of the first embodiment described above, the memory 41 and the reference circuit 42 are provided in the body 12b of the electronic camera 12, but the memory 41 and the reference circuit 42 are provided in the flash light emitting device 11. It may be provided. Furthermore, in the camera system 10 of the first embodiment described above,
The case of performing flash photography using the color filters 13 and 14 incorporated in the flash light emitting device 11 has been described as an example, but the present invention can also be applied to the case of performing flash photography using an external color filter.

If the external color filters are dedicated to the flash light emitting device, as shown in FIG.
3, 54, 55 have unique projections 53a, 54a, 55a
The flash light emitting device 56 is provided with a color filter 5
Depending on the mounting state of 3, 54, 55, the protrusions 53a, 54
Switch turned on / off by a, 55a (not shown)
(Detection means corresponding to the color filter identification circuit 24 described above) may be provided.

On the other hand, when the external color filter is not exclusively used for the flash light emitting device, the flash light emitting device or the body of the electronic camera is provided with a switch that can be operated from the outside to identify the color filter (the above-mentioned color filter). Identification circuit 24
(Detection means) corresponding to When the body of the electronic camera is provided with the liquid crystal display unit, the menu of the liquid crystal display unit can be used.

Further, in the above-described first embodiment, the camera system 1 in which the two color filters (13, 14) can be mounted.
Although the example of 0 has been described, the number of color filters may be one or three or more. The color characteristic of the color filter is not limited to the above example, and may be, for example, a blue wavelength range (400 nm).
It is possible to use a color filter having a color characteristic of transmitting mainly (.about.500 nm). With this color filter, the color temperature (FIG. 3) of the flash emitted from the light emitting unit 21 can be converted into a high color temperature.

Here, in the present specification, the color filter means (1) a cut-off filter that transmits only light having a specific wavelength or less, or only light having a specific wavelength or more,
(2) An optical element such as a bandpass filter that transmits only light in a specific wavelength range. further,
In the above-described first embodiment, the example of the camera system 10 in which the flash light emitting device 11 and the body 12b of the electronic camera 12 are detachably configured has been described, but the flash light emitting device is configured integrally with the body of the electronic camera. The present invention can also be applied to a camera system. In this case, the communication means between the flash light emitting device and the body becomes unnecessary.

Further, in the above-described first embodiment, the flash light emitting device 11 of the external automatic light control system has been described as an example, but the present invention is not limited to this configuration. In addition, the present invention can be applied to a TTL dimming flash light emitting device. In this case, the light emission control circuit 22 in the flash light emitting device 11 is
It is provided in the second body 12b. (Second Embodiment) Next, a second embodiment of the present invention will be described.

The second embodiment of the present invention corresponds to claims 1, 2, and 5. In the second embodiment, a camera system 60 (FIG. 9) in which a color filter can be attached to a taking lens of an electronic camera will be described. The camera system 60 of the second embodiment includes a flash light emitting device (not shown) and an electronic camera 61. The electronic camera 61 is provided with a color filter identification circuit 62 (corresponding to "detection means" in claims) in addition to the above-described components (12a, 31 to 36) of the electronic camera 12.

The color filter identification circuit 62 is used for the electronic camera 6
It is detected whether or not the color filters 63 and 64 are attached to the first taking lens 13a (that is, whether or not the color filters 63 and 64 are inserted in the optical path L2 of the subject light flux), and the color filter 63 or the color filter 64 is attached to the taking lens 13a. It is a switch that detects the color characteristics of the color filter when it is attached (that is, inserted in the optical path L2).

Therefore, the color filter signal indicating the detection result by the color filter identification circuit 62 is included in the color filter 63.
Signal indicating that is installed (inserted), and the color filter 64
Signal indicating that is attached (inserted), and the color filter 63
And the signal indicating that neither the color filter 64 is attached (inserted) exists. Color filter identification circuit 6
The color filter signal (any one of the above three types) indicating the detection result of 2 is transmitted to the adjustment circuit 34. The color filter identifying circuit 62 and the adjusting circuit 34 constitute a white balance adjusting device.

In the camera system 60 of the second embodiment configured as described above, the color characteristics of the color filter (63 or 64) are taken into consideration in consideration of the detection result of the color filter identification circuit 62 provided in the electronic camera 61. The white balance adjustment amount is calculated in consideration, and the white balance of the image signal (three primary color signals) obtained from the image sensor 31 is adjusted based on the obtained white balance adjustment amount. Therefore, even when the image of the subject is captured using the color filter (63 or 64), proper white balance adjustment can be automatically performed, and a photograph with a color tone that reflects the photographer's intention can be obtained. it can.

In the above embodiment, the color filter
An example of calculating the white balance adjustment amount in consideration of the color characteristics of the color filters (13, 14) (63, 64) when (13, 14) (63, 64) is attached (inserted) will be described. However,
The present invention is not limited to this configuration. For example, by the color filter identification circuit (14, 62), the color filter (13, 14)
When the mounting (insertion) of (63, 64) is detected, the white balance adjustment may not be performed on the image signal from the image sensor 31 in consideration of the detection result. Even in this case, it is possible to obtain a photograph that reflects the intention of the photographer.

Further, in the above-described embodiment, the camera system for adjusting the white balance in consideration of the mounting when the color filter is mounted on either the flash light emitting device or the photographing lens has been described as an example. However, the present invention can be applied to a camera system in which color filters can be attached to both the flash light emitting device and the taking lens, and the white balance can be adjusted in consideration of the attachment.

Further, in the above embodiment, the white balance of the image signal composed of the three primary color signals is adjusted.
Even for an image signal composed of a plurality of color signals, the white balance can be adjusted similarly. Further, the example in which the electronic camera 12 is a digital still camera has been described, but the present invention can be applied to a digital video camera.

Further, in the above embodiment, the white balance adjusting device 10 is used in the camera systems 10, 50 and 60.
The white balance adjusting device 10a, (62, 34) of the present invention is not limited to the camera system, but the subject (sample) is not limited to the camera system.
It can also be applied to a microscope system that observes a sample by capturing an image of, and various color imaging devices.

[0066]

As described above, according to the white balance adjusting apparatus of the present invention, the white balance adjustment of the image signal can be properly performed even when the image of the subject is picked up by using the color filters. Further, according to the camera system of the present invention, even when an image of a subject is captured using a color filter, it is possible to obtain a photograph with a color tone that reflects the photographer's intention.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an appearance of a camera system 10 according to a first embodiment.

FIG. 2 is a block diagram showing an internal configuration of the camera system 10 of the first embodiment.

FIG. 3 is a graph showing spectral characteristics of flash light itself.

FIG. 4 is a graph showing spectral characteristics of flash light after passing through a color filter 13.

FIG. 5 is a graph showing spectral characteristics of flash light after passing through a color filter.

FIG. 6 is a graph showing spectral characteristics of a fluorescent lamp.

FIG. 7 is a block diagram showing an internal configuration of a camera system 50 of a modified example.

FIG. 8 is a perspective view showing a configuration of external color filters 53 to 55.

FIG. 9 is a block diagram showing an internal configuration of a camera system 60 of a second embodiment.

[Explanation of symbols]

10,50,60 camera system 11 Flash light emitting device 12 electronic camera 13, 14, 63, 64 color filters 24,62 color filter identification circuit 31 Image sensor 34 Adjustment circuit 41 memory 42 Reference circuit 43 White balance calculation circuit 44,51 Signal processing circuit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5C065 AA03 BB02 CC01 DD26 EE06                       FF05 GG23 GG26 GG32                 5C066 AA01 EA14 KE07 KM05 KM10                       KP02

Claims (5)

[Claims] 1. A detection means for detecting whether or not a color filter is inserted in at least one optical path of an illumination light flux to an object and an incident light flux from the object to an image sensor, and a detection result by the detection means. In consideration of the above, a white balance adjusting apparatus comprising: an adjusting unit that adjusts a white balance of an image signal obtained from the image sensor. 2. The white balance adjusting apparatus according to claim 1, wherein the detecting unit detects a color characteristic of the color filter inserted in the optical path when the color filter is inserted in the optical path. The adjusting means calculates a white balance adjustment amount in consideration of the color characteristics detected by the detecting means, and adjusts the white balance of the image signal based on the white balance adjustment amount. White balance adjustment device. 3. A camera system comprising the white balance adjusting device according to claim 1 or 2, a flash light emitting device for emitting the illumination light flux as flash light, and an electronic camera body having the image pickup device. The flash light emitting device has a mounting portion for the color filter in the vicinity of a portion that emits the illumination light flux, and the detecting unit is based on whether or not the color filter is mounted on the mounting portion. A camera system for detecting whether or not the color filter is attached to the optical path. 4. The camera system according to claim 3, wherein the flash light emitting device and the electronic camera body are detachable, the detecting means is provided inside the flash light emitting device, and the adjusting means is provided. The camera system further comprises a communication unit which is provided inside the electronic camera body and which transmits a detection result of the detection unit to the adjustment unit. 5. A white balance adjusting device according to claim 1, a photographing lens for guiding the incident light flux from the subject to the image pickup device, and an electronic camera body having the image pickup device. In the camera system, the photographing lens has a mounting portion for the color filter in the vicinity of a portion that takes in the incident light flux, and the detecting unit determines whether or not the color filter is mounted in the mounting portion. A camera system for detecting whether or not the color filter is attached to the optical path based on the above.