JP2007033745A - Photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographing device that has light emitting parts by which the color of flash light emitted by a xenon tube or the like is corrected to a color corresponding to the color temperature of a field. <P>SOLUTION: The photographing device includes the first light emitting part having the xenon tube 116, and the second light emitting part having three light emitting diodes 114r, 114g and 114b, namely, red, blue and green. A system control circuit 110 instructs a light emission quantity control means 112B to cause the xenon tube 116 to emit light. Also, the system control circuit 110 instructs a light emission quantity control means 112A to cause at least one of the three light emitting diodes 114r, 114g and 114b to emit light in order to produce the color of emitted light, which corresponds to a color temperature detected by a color temperature detecting means 141. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photographing apparatus that includes an image sensor and generates an image signal by forming a subject image on the image sensor.

  Many photographic devices are equipped with a light emitting unit that emits flash light toward the subject in synchronization with shooting, and the xenon tube or the like can be used to allow the flash light to reach distant subjects. The arc tube is often deployed. This xenon tube is well known as an arc tube capable of emitting flash light with a color corresponding to almost the same color temperature as sunlight. When shooting is performed with flash light emitted from the xenon tube, an image having substantially the same color as that actually seen with one's own eyes can be obtained.

  However, when it is cloudy, the color of an image obtained by photographing with flash light may feel slightly different from the color of an actual subject even when it is outdoors. Such a tendency becomes even more prominent in indoor shooting in which incandescent lamps and fluorescent lamps are used for illumination.

  For example, when the light source on the illumination side is an incandescent lamp (tungsten light), the color of the illumination light is lower than the color temperature of the flash light emitted from the xenon tube (reddish white) Therefore, the color of an image obtained by photographing with flash light is different from the color when an object under the incandescent lamp is actually viewed with eyes.

  Usually, a digital camera is equipped with a white balance circuit, and the white balance is adjusted by using the light received by each light receiving element of the image sensor by the white balance circuit. Thus, there is no problem as long as the difference between the color temperature of the flash light and the color temperature of the illumination light can be eliminated.

  However, the white balance has only multiple types of white balance, such as under clear sky, under cloudy sky, under tungsten light, and under fluorescent light. For example, even in the automatic mode, one of these multiple types of white balance is available. (The subject whose color temperature is close) is selected, and only white balance processing is performed according to the color temperature close to the color temperature of the subject before the flash light emission. Then, since white balance processing according to the color temperature of the incandescent lamp before flash light emission is performed, flash light having a different color temperature is emitted and shooting is performed. The color of the image obtained by shooting is different from the color when the subject under the incandescent lamp is actually viewed with eyes.

  In order to cope with such a problem, it is conceivable to perform white balance in advance according to the color temperature of the flash light at the time of flash emission. However, white balance is performed by setting the color temperature of the flash light in advance. If it does in this way, the problem that color irregularity will generate | occur | produce in a picked-up image will arise in the environment where both external light and flash light are distributed.

  If there is an arc tube that can emit flash light toward the subject with an emission color corresponding to the color temperature of the object field at the time of white balance adjustment before flash emission, an appropriate white balance process will be performed. Thus, the above problem is solved, but no such arc tube can be found anywhere.

  By the way, since the development of blue light emitting diodes has made it possible to emit white light with a light emitting diode (hereinafter referred to as LED), there has been a movement to use LEDs as light emitting elements that emit flash light. There has been proposed a technique for illuminating a subject using an LED when performing close-up photography in one of the movements using the LED (see, for example, Patent Document 1). By using the technique of this patent document 1, it is possible to freely emit flash light of an emission color corresponding to the color temperature of the subject.

  However, since the light emission power of the LED is small, it is necessary to use a large number of LEDs side by side to reach a distant subject (see, for example, Patent Document 2), so a xenon tube or the like is used from the viewpoint of cost and production. There are still many people who think it would be advantageous.

However, when an arc tube such as a xenon tube is used, the emission color of the xenon tube cannot be changed to an emission color corresponding to the color temperature like an LED.
Japanese Patent Laid-Open No. 2003-233109 JP 2002-116481 A

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an imaging device including a light emitting unit that can correct the emission color of flash light emitted from a xenon tube or the like to a color corresponding to the color temperature of illumination. .

An imaging device of the present invention that achieves the above object includes an imaging lens and an imaging device, and forms an image of a subject on the imaging device with the imaging lens and performs imaging to generate an image signal with the imaging device.
A color temperature detection unit that detects a color temperature of the object scene based on an image signal generated by the imaging element;
A first light emitting unit that emits flash light toward a subject and that cannot adjust the emission color;
A second light-emitting unit that emits light having a color temperature adjusted toward the subject and that can adjust the emission color;
In synchronization with shooting, the first light emitting unit emits flash light, and the second light emitting unit corresponds to the color temperature detected by the color temperature detecting unit when combined with the flash light. And a light emission control unit that emits the color light emitted to the subject.

  According to the photographing apparatus of the present invention, when the light emission control unit causes the first light emitting unit to emit flash light, and the second light emitting unit with adjustable emission color is combined with the flash light. In addition, it is possible to emit color light of a luminescent color that becomes a color corresponding to the color temperature detected by the color temperature detection unit.

  That is, when the first light emitting unit is a xenon tube or the like, an imaging apparatus including a light emitting unit capable of correcting the emission color of flash light emitted from the xenon tube or the like to a color according to the color temperature of the illumination. Realized.

  Here, the light emission control unit causes the second light emitting unit to emit light from before the start of exposure by the current photographing to after the start of exposure by the current photographing, and then causes the first light emitting unit to emit light during the exposure. It is preferable that

  For example, the light emission control unit starts light emission to the second light emitting unit before the start of exposure by the current photographing, whereby light emission of the second light emitting unit as red-eye reduction light emission or ranging auxiliary light is performed. In addition, the light emission of the second light emitting unit is also used as the light emission for correcting the color temperature as described above by continuing the light emission after the start of exposure.

  Further, it is preferable that a power storage capacitor is provided, and that both the first light emitting unit and the second light emitting unit emit light upon receiving the supply of power stored in the capacitor.

  Then, even if the power sources of the first light emitting unit and the second light emitting unit are not separately provided, the power sources of both the light emitting units are shared by the single power storage capacitor.

  In addition, it is preferable that the light emission control unit first causes the first light emission unit to emit light and then causes the second light emission unit to emit light during the exposure period of the current photographing.

  Considering that both the first light-emitting unit and the second light-emitting unit are actually mounted on the photographing apparatus, the first light-emitting unit and the second light-emitting unit have different withstand voltages, Sometimes the operating voltage is different. In such a case, when the first light emitting unit and the second light emitting unit are operated, it is necessary to separately provide a power source for each of the light emitting units.

  Therefore, by using the fact that the magnitude of the voltage generated between the electrodes of the power storage capacitor changes with time, first the first light emitting unit on the side where the operating voltage is large is caused to emit light, and then the operation is performed. If the second light emitting unit that requires only a small voltage is allowed to emit light, efficiency can be improved in terms of power supply and only one power source is required. Therefore, the configuration of the light emitting unit is simplified and the size can be reduced. It becomes like.

  Here, the second light emitting unit is composed of a set of a plurality of light emitting elements that respectively emit a plurality of color lights, and the light emission control unit includes the plurality of light emitting elements in the second light emitting unit. Are preferably made to emit light sequentially.

  As described above, in order to simplify the configuration of the light emitting unit, if the capacitor is commonly used as a power source for the first light emitting unit and the second light emitting unit, the second light emitting unit includes a plurality of light emitting elements. In the case of a set, if all of the plurality of light emitting elements are caused to emit light at the same time, it may not be possible to obtain a sufficient amount of light emission color necessary to correct the color temperature. There is sex.

  Therefore, first, it is possible to correct the color temperature appropriately by causing the light emitting element that emits the light emission color necessary for correcting the color temperature to emit light while sufficient electric power is accumulated in the capacitor. .

  That is, it is preferable that the light emission control unit causes the second light emitting unit to sequentially emit light from a light emitting element having a large light emission amount in the current photographing.

  By doing so, the difference in color temperature in the current photographing is surely eliminated, and the power of the capacitor is effectively utilized.

  Here, the first light emitting unit includes a xenon tube and causes the xenon tube to emit flash light, and the second light emitting unit includes an LED that emits light whose emission color can be adjusted. It is preferable that the LED emit light.

  Then, even if flash light whose emission color cannot be adjusted is emitted from the xenon tube, the light of the color whose emission color is corrected to the emission color according to the color temperature when the flash light is combined is emitted from the LED. Light is emitted.

  Further, since the LED is relatively inexpensive, even if the second light emitting unit is mounted on the photographing apparatus in addition to the first light emitting unit, the cost required for manufacturing the photographing apparatus is relatively low. The effect that it can suppress to something is also acquired.

   As described above, an imaging apparatus including a light emitting unit that can correct the emission color of flash light emitted from a xenon tube or the like to a color corresponding to the color temperature of the object scene is realized.

  Embodiments of the present invention will be described below.

  FIG. 1 is a view showing an appearance of a digital camera 1 according to an embodiment of the present invention.

  A lens barrel 100 is provided at the front center of the digital camera 1 shown in FIG. A photographing lens 1021 is built in the lens barrel 100. A finder 101 is provided above the lens barrel 100, and a light emission window 102 is provided beside the finder 101. From the light emitting window 102, the flash light is emitted toward the subject when it is determined by the system control circuit described later that the flash light needs to be emitted.

  Also, a shutter button 104, a mode dial 105, and a single / continuous shooting switch 106 are provided on the upper surface of the camera body.

  FIG. 2 is a block diagram showing the internal configuration of the digital camera 1 shown in FIG.

  The internal configuration of the digital camera 1 will be described with reference to FIG.

  In the digital camera 1 of the present embodiment, all processing is controlled by the system control circuit 110. The operation unit such as the shutter button 104, the mode dial 105, and the single / continuous shooting switch 106 shown in FIG. 1 is connected to the input unit of the system control circuit 110, and any one of these operators is connected. When an operation signal is supplied to the system control circuit 110 by an operation, processing corresponding to any one of these operators is started.

  Although not shown in FIG. 1, the digital camera 1 according to the present embodiment has a detachable storage medium 200 such as a memory card mounted in the medium loading chamber 100A and the memory card 200 loaded in the medium loading chamber 100A. Since image data representing a photographed image is recorded, a storage medium attachment / detachment detecting means for detecting whether a memory card as a storage medium is mounted in the medium loading chamber 100A is provided. . Further, although not shown in FIG. 1, on the back side, an image display ON / OFF switch 107 and an image display unit for detecting opening / closing of a protective door for protecting the surface of the display panel provided on the back side. Open / close detection means 109 is also provided. Signals from the storage medium attachment / detachment detection means, the image display ON / OFF switch 107, and the image display section opening / closing detection means 109 are also supplied to the system control circuit 110, and the system control circuit 110 outputs these signals. In response, the process is executed.

  Further, the system control circuit 110 instructs the zoom control means in accordance with an operation of a zoom switch (not shown) to move the zoom lens in the photographing lens 1021, or performs measurement according to the distance measurement result obtained by TTL distance measurement. The focus lens in the photographing lens is moved by instructing the distance control means.

  Further, in the system control circuit 110, TTL photometry is performed along with the TTL distance measurement by the system control circuit 110 based on the image data generated by the CCD solid-state imaging device 120. Depending on the photometric result of the TTL photometry, the exposure control means 1040 is instructed to cause the exposure control means to adjust the aperture of the aperture 1041. Further, at the time of photographing, the first light emission amount control means is based on the photometric result. 112A is instructed to drive the xenon tube 116 by the xenon tube driving circuit 115 and at least one of the LED 114r that emits red light, the LED 114g that emits green light, and the LED 114b that emits blue light. By driving, the flash light from the xenon tube 116 and the color light from at least one of the three LEDs are combined to irradiate the subject with flash light of a color corresponding to the color temperature. I am also doing it.

In the present invention, the xenon (Xe) tube 116 corresponds to the first light emitting portion according to the present invention, and the three light emitting diodes 114r, 114g, and 114b correspond to the second light emitting portion according to the present invention. As is well known, since the xenon (Xe) tube emits flash light whose emission color cannot be adjusted, the LED 3 whose emission color can be adjusted in addition to the flash light whose emission color cannot be adjusted. The light emission color of the flash light is adjusted to a color corresponding to the color temperature by emitting at least one of the light sources. For example, blue light (B) of three light emitting diodes is emitted in accordance with the flash light The light emitting diode 114b emits light to give a light emission color corresponding to a high color temperature (bluish white), or a low color by emitting red light of the three light emitting diodes in accordance with the flash light. It is also possible to change the emission color according to temperature (reddish white).

  In this way, the amount of light emitted from each light emitting diode can be individually adjusted, so that the flash color can be adjusted at any time according to the color temperature detected by the color temperature detector. can do.

  Here, an outline of a photographing process of a digital camera having two light emitting units, such as a xenon tube 116 that emits flash light whose light emission color cannot be adjusted and a light emitting diode 114 that emits light whose light emission color can be adjusted, will be described.

  In the present embodiment, when the power switch of the digital camera 1 is turned on, the overall operation of the digital camera 100 is comprehensively controlled by the system control circuit 110 in accordance with the procedure of the overall processing program in the nonvolatile memory 1101. Processing is started. In this example, a power switch (not shown) of the digital camera 100 is turned on to suppress power consumption of the battery, and the power switch is turned on by the system control circuit 110 (power from the battery is always supplied to the system control circuit). For the first time when it is detected that the battery has been inserted, power is supplied from the battery Bt to each block via the power control means 111b.

  First, the configuration and operation of the processing unit related to the photographing process of the digital camera that is in an operating state by supplying power to each unit will be briefly described with reference to FIG.

  As shown in FIG. 2, the lens barrel 100 shown in FIG. 1 is provided with a photographing lens 1021 such as a focus lens and a zoom lens, and a diaphragm 1041 for adjusting the amount of light. Also, in this example, a lens barrier 1011 for protecting the lens is shown. When the power switch is turned on, the lens barrier 1011 is released, and the photographing lens 1021 is surfaced as shown in FIG. It is configured to be exposed to.

  When the mode dial 105 is switched to the photographing side when the power switch is turned on, the subject image first formed on the CCD solid-state photographing element 120 through the photographing lens 1021 exposed on the surface is the timing. Based on the timing signal from the generation circuit 121, the data is thinned out at predetermined intervals (every 33 ms) and output. The output image signal is converted from an analog image signal to a digital image signal by the A / D conversion circuit 130, and the digital image signal is further guided to the image processing circuit 140 under the control of the memory control unit 111a. The image processing circuit 140 converts the RGB image signal into a YC signal, and is further guided to the image display memory 151 under the control of the memory control unit 111a to store the image signal representing the through image in the image display memory 151. It has come to be. The image signal for one frame stored in the image display memory 151 is read out by the memory control unit 111a, guided to the D / A conversion circuit 160, converted into an analog image signal, and then supplied to the image display unit 150. Is done. In this example, an image display memory 151 is provided so that new image signals can be supplied to the image display unit 150 at predetermined intervals, and image signals for at least two frames are stored in the image display memory 151. By memorizing, the display timing can be adjusted well.

  In the present embodiment, an example is shown in which the white balance adjustment and γ correction, and as described above, photometry and distance measurement are performed by the system control circuit 110, and RGB analog signals are supplied to the system control circuit 110. Then, white balance adjustment, γ correction, photometry, distance measurement, and the like are performed in the system control circuit, and aperture control of the aperture 1041 and placement control of the focus lens (1021) are performed. ing.

  Here, the operation of each unit will be described in detail along with the flow of the image signal.

  First, the operation of each unit will be briefly described along the flow of the image signal of the through image.

  In accordance with a timing signal from the timing generation circuit 121 (for example, every 33 ms), an image signal representing a subject image formed on the light receiving surface on the CCD solid-state image sensor 120 by the photographing lens 1020 is converted into an A / D conversion circuit 130 at the subsequent stage. To output. The image signal converted from the analog image signal to the digital image signal by the A / D conversion circuit 130 is guided to the image processing circuit 140 under the control of the memory control unit 111a. The image processing circuit 140 separates the R, G, and B color signals and supplies them to the color temperature detection circuit 141. The R, G, and B color signals are displayed on the YC for display using a color conversion matrix. It is converted into a signal and supplied to the image display memory 151 in the subsequent stage. The R, G, and B color signals are supplied to the subsequent color temperature detection circuit 141. When the color temperature detection circuit 141 detects each color temperature, for example, each color amplifier in the system control circuit 110 receives each color. A gain corresponding to the temperature is set, and white balance adjustment of the image signal is performed in the system control circuit 110. When white balance adjustment is performed in the system control circuit 110, as described above, the gain of each color amplifier is set so that the color temperature is the closest to one of clear sky, cloudy weather, tungsten light, and fluorescent light. It is set and white balance adjustment is performed.

  The YC signal is supplied to the image display memory 151 and supplied to the image display memory 151 for storage. The image display memory 151 stores at least two frames of image signals. Of the two frames of image signals, one frame of image signals stored at an old time is D / A converted. The image is guided to the unit 160, converted into an analog signal, supplied to the image display unit 150, and a through image is displayed on the display screen.

  As described above, the TTL distance measurement is performed in the system control circuit 110, and the distance measurement control means 1030 is instructed based on the distance measurement result so that the focus lens (1021) is always placed at the focal point. When the zoom switch is operated, the zoom control means 1020 is instructed to place the zoom lens (1021) at a position corresponding to the zoom magnification by the operation of the zoom switch.

  When the shutter button 104 is pressed while the through image with the zoom magnification according to the operation position of the zoom switch that is always in focus is displayed in this way, the photographing process is started.

  The system control circuit 110 causes the timing generation circuit 121 to supply an exposure start signal to the CCD solid-state imaging device 120 at the timing when the shutter button 104 is pressed. At this time, if the system control circuit 110 determines that flash light emission is necessary based on the photometric result, the first light emission amount control means 112A is instructed to the xenon tube 116 in synchronization with the depression of the shutter button 104. While flash light is emitted, light is emitted to at least one of the three LEDs so that the emission color of the flash light becomes a color corresponding to the color temperature detected by the color temperature detection circuit 141 during the through image display. Let

  In the present embodiment, the first light emission amount control means 112A is notified of the ratio of the amounts of red light, green light, and blue light according to the color temperature detected by the color temperature detection circuit 141, and the LED drive circuit 113. Since at least one of the LEDs emitting red light, green light, and blue light is driven according to the ratio, any color temperature can be adjusted according to the color temperature. At least one color light of red light, green light, and blue light is emitted so that the flash light is corrected in color.

  As described above, at least one of the three LEDs so as to obtain a light emission color corresponding to the color temperature detected by the color temperature detection unit 141 when combined with the flash light emitted from the xenon tube 116 whose light emission color cannot be adjusted. As described above, the white balance adjustment unit in the system control circuit 110 at the subsequent stage has a gain corresponding to the color temperature of any of the clear sky, cloudy weather, tungsten light, and fluorescent lamp as described above. Even if the amplifier is set, flash light corresponding to any one of the color temperatures is emitted toward the subject and photographing is performed, so that suitable white balance adjustment is performed.

  After flash light is emitted so that white balance adjustment is suitably performed in this way, the system control circuit 110 instructs the timing generation circuit 121 to supply an exposure end signal to the CCD solid-state imaging device 120.

  Then, an image signal is output from the CCD solid-state imaging device 120 to the A / D conversion circuit 130 in synchronization with the exposure end signal. The analog image signal output from the CCD solid-state imaging device 120 is converted into a digital image signal by the A / D conversion circuit 130, and the digital image signal is further controlled by the memory control unit 111a to be stored in the memory via the bus. 180. When all the image signals composed of all the pixels included in the CCD solid-state imaging device 120 are stored in the memory 180, this image signal is read out under the control of the system control circuit 110, and the system control circuit 110 reads the image signal described above. White balance adjustment and gamma correction are performed. Further, the image signal subjected to white balance adjustment and gamma correction is supplied to the image processing circuit 140 via the bus and converted into a YC signal, and then supplied to the compression / decompression circuit 190 via the bus. The image signal consisting of the signal is compressed and stored in the storage medium 200, here the memory card.

  This makes it possible to adjust the light emission color of the flash light to the white balance, so that a suitable white balance adjustment is performed in the system control circuit to obtain a color according to the color temperature of the object scene. The possessed image data can be obtained reliably.

  In addition, a communication means that can perform wireless communication with the outside when the antenna 1101 is connected to the connector 1105 on the side surface of the camera body via a cable, a display unit 1102 and a memory 103 that transmit operation contents to the user, and the like. Has been deployed.

  FIG. 3 is a flowchart showing a procedure of photographing processing involving flash light performed by the system control circuit 110.

  In FIG. 3, in synchronization with shooting, the xenon tube (first light emitting unit according to the present invention) emits flash light and the flash light is combined with the LED (second light emitting unit). A processing procedure for emitting light having a color corresponding to the color temperature detected by the color temperature detection unit 140 is shown.

  In step S301, it is determined whether the shutter button 104 is half-pressed. If it is determined that the shutter button 104 is not half-pressed, the process proceeds to the No side and the process of Step S301 is repeated. If it is determined that the shutter button 104 is half-pressed, the process proceeds to Yes and the distance measurement ( AF), photometry (AE), and white balance adjustment (AWB) are performed.

  Further, the process proceeds to the next step S303, where it is determined whether or not the shutter button 104 has been fully pressed. If it is determined in step S303 that the shutter button 104 has not been fully pressed, the process proceeds to No and the process of the step is repeated. If it is determined that the shutter button 104 has been fully pressed, the process proceeds to Yes and the exposure signal is sent to the timing generation circuit 121 in step S304. To cause the CCD 120 to start exposure.

  Further, the process proceeds to the next step S305 to instruct the first and second light emission amount control means 112A and 112B to cause the xenon tube 116 to emit light, and at least one of the three LEDs of red, blue, and green. First, light is emitted so that the flash light from the xenon tube has a color corresponding to the color temperature detected by the color temperature detection circuit.

  In this case, at least one of the LEDs 114r, 114g, and 114b is caused to emit light simultaneously with the flash light, so that a certain one in the spectral radiant flux is added to the spectral radiant flux of the flash light originally possessed by the xenon tube. By emitting light in the wavelength range (at least one of red light, green light, and blue light), the emission color of the flash light is made reddish white (low color temperature), or bluish white ( The color temperature is high).

  When a predetermined shutter time has elapsed, in step S306, a timing signal is supplied from the timing generation circuit 121 to the CCD 120, the exposure to the CCD solid-state imaging device 120 is terminated, and the processing of this flow is terminated.

  In this manner, an imaging apparatus including a light emitting unit that can correct the emission color of flash light emitted from a xenon tube or the like to a color according to the color temperature of the object scene is realized.

  Further, as described above, at least one of the xenon tube and the three LEDs may be caused to emit light at the same time, but the second light emitting unit from before the exposure start by the current photographing to after the exposure start by the current photographing. After the LED is continuously emitted, the first light emitting unit may emit light during exposure. If it does in this way, light emission of LED can be utilized as AF auxiliary light, or light emission for red-eye reduction can be utilized.

  FIG. 4 is a flowchart showing a processing procedure when the xenon tube is caused to emit light while the LED is continuously emitting light from before the start of exposure by the current shooting to after the start of exposure by the current shooting. 4 is performed by the system control circuit 110 as in FIG.

  In step S401, it is determined whether the shutter button 104 is half-pressed. If it is determined in step S401 that the shutter button 104 is not half-pressed, the process proceeds to No and the process in step S401 is repeated. If it is determined that the shutter button 104 is half-pressed, the process proceeds to Yes and white balance adjustment (AWB) is performed in step S402. ). When this white balance adjustment is performed, the color temperature of the object scene is notified from the color temperature detection circuit 141. Therefore, in step S403, the second light emission amount control unit 112B is instructed to emit light according to the color temperature. In order to change the color, at least one of the LEDs 114 is made to emit light continuously after the start of exposure. By doing so, the LED 114 emits light before photographing, and therefore the LED 114 can be used as red light emission or AF auxiliary light.

  Proceeding to the next step S404, distance measurement (AF) is performed using the emitted light, and the shutter button is fully pressed in the next step S405. If it is determined in this step S405 that it has not been fully pressed, step S405 is repeated. If it is determined in this step S405 that it has been fully pressed, the process proceeds to Yes, and the timing signal is sent to the timing generation circuit 121 in the next step S406. Supplying to the CCD 120 causes the CCD solid-state imaging device 120 to start exposure. After a predetermined time, the process proceeds to the next step S407, where the xenon tube 116 is caused to emit flash light. Further, when a predetermined time (shutter time) elapses after the flash light is emitted, the process proceeds to the next step S408, where an exposure end signal is supplied to the timing generation circuit 121, and the CCD 120 ends the exposure. After proceeding to the next step S409 to stop the light emission of each LED 114r, 114g, 114b, the processing of this flow is terminated.

  In this way, the light emitted from the second light emitting unit (three light emitting diodes 114r, 114g, 114b) is used for correcting the color temperature, used as AF auxiliary light, and used as light for reducing red-eye. If it does, light emission of LED will be utilized still more effectively.

  FIG. 5 is a diagram for explaining another embodiment.

  The xenon tube driving circuit 115 and the LED driving circuit 113 shown in FIG. 3 become one driving circuit 1130, and the first light emission amount control means 112A and the second light emission amount control means 112B become one light emission amount control means. The configuration is the same as that of FIG.

  FIG. 5 shows that the light emission on the LED 114 side is also accumulated in the capacitor MC by utilizing the fact that the capacitor MC for power storage is provided in the Xe tube driving circuit 115 for driving the xenon (Xe) tube 116. The configuration in the case where the drive circuit 1130 is made common so that the power can be utilized is shown.

  FIG. 6 is a diagram for explaining the internal configuration of the shared drive circuit 1130.

  FIG. 6 shows a circuit configuration in the case where the switch SW is switched by the light emission amount control circuit 112A to first cause the xenon tube 116 to emit light and then cause all the LEDs 114r, 114g, and 114b to emit light simultaneously.

  As shown in FIG. 6, the drive circuit 1130 is provided with a capacitor MC for storing power, so that the power supply path from the capacitor MC is switched to the xenon tube 116 side or switched to the LED 114 side. A switch SW with a control terminal is provided. This switch SW with a control terminal is a single-pole, three-throw switch, and can be switched to any one of the three contacts S1, S2, S3 according to an instruction from the light emission amount control circuit 112. ing.

  In this example, since the capacitor MC has to be charged except when light is emitted, the switch MC is switched to the contact position S2, and the capacitor MC is charged by the charging circuit including the battery BT and the booster circuit 1121A. Like to do. At this time, since it is difficult to know the charging state of the capacitor MC, whether the capacitor MC is fully charged by detecting the voltage of the electrode of the capacitor MC by the detection circuit 1122 in order to detect the charging state of the capacitor MC. It is also possible to detect whether or not. Further, if the voltage of the capacitor MC rises to near full charge, the voltage of the capacitor MC becomes higher than that of the booster circuit 1121 and current may flow backward to the booster circuit 1121 side. A diode D1 is connected to the end so that the cathode side is on the capacitor side.

  When the light emission amount control circuit 112 receives a light emission instruction from the system control circuit 110 when the full charge voltage is detected in this way, the light emission amount control circuit 112 first sets the switch SW to the contact S1 side. The discharge is started by the path of the capacitor MC, the xenon tube 116, and the switch SW. At this time, a high voltage is supplied between the electrodes so that light is efficiently emitted from the xenon tube 116, and at the same time, a trigger signal is supplied to the trigger coil to excite the xenon tube so that the xenon tube quickly transitions to a discharge state. Yes.

  Further, after causing the xenon tube to emit light, the light emission amount control circuit 112A switches the switch SW to the contact S3 side when the detection circuit 1122 detects a decrease in the voltage generated in the capacitor MC to 50V. The light emitting diode is caused to emit light by the remaining power of the capacitor.

  In this way, the xenon tube 116 and the three LEDs 114r, 114g, 114b can be made to emit light sequentially by supplying power from one capacitor.

  FIG. 7 is a diagram for explaining how the state of the voltage generated in the capacitor MC changes with time. The horizontal axis represents time, the vertical axis represents the value of the voltage generated in the capacitor MC, and the first part of the horizontal axis indicating time indicates the time required for charging and the time for waiting for light emission.

  As is well known, the xenon tube 116 emits light because no discharge occurs unless a high voltage of 300 V or higher is applied between the electrodes of the xenon tube while supplying a trigger signal to the trigger coil of the xenon tube to excite the inside of the xenon tube. do not do. In general, a capacitor MC is used in a drive circuit for causing a xenon tube to emit light so as to generate the high voltage (300V). On the other hand, the operating voltage of the LED is as low as 50V.

  Therefore, as shown in FIG. 7, during the exposure period of the current photographing, first, the xenon (Xe) tube is caused to emit light, and the LED 114 emits light when the voltage of the capacitor MC decreases to 50V.

  In this way, until now, since it is not possible to maintain the light emission even if it is added to the xenon tube, the power of 50 V or less that has been discarded is efficiently utilized on the LED side.

  Here, if the three light emitting diodes 114r, 114g, and 114b are caused to emit light at the same time, the current required to emit light at a certain voltage does not flow when the voltage gradually decreases from 50V.

  Therefore, the capacitor MC is configured so that it can be switched to one of a plurality of resistors (R1, R2, R3, R4) so that the power stored in the capacitor MC can be used more effectively. A modified example will be described so that the stored power can be used more effectively.

  FIG. 8 is a diagram for explaining an example modified so that the power stored in the capacitor MC can be used more effectively. In FIG. 8A, when the voltage of the main capacitor MC decreases with time, the plurality of resistors R1 to R4 are sequentially switched to those having a small resistance value by the switch SW1, and between the electrodes of each LED. The state when the applied voltage is kept in the LED light emitting region shown in FIG. 8A is shown, and FIG. 8B shows the state for realizing the state shown in FIG. The circuit configuration is shown.

  The magnitudes of the resistance values shown in FIGS. 8A and 8B have a relationship of R1> R2> R3> R3.

  As shown in FIGS. 8 (a) and 8 (b), when the voltage of the capacitor MC decreases, the resistors are sequentially switched from a larger one (R1) to a smaller one (R4). As a result, the voltage between the electrodes necessary for causing the LEDs 114r, 114g, and 114b to emit light all at once (the voltage indicated as the LED light emitting region shown in FIG. 8A) is always applied to the LEDs. ) Always be able to secure.

  In this way, even if the power stored in the capacitor MC is effectively utilized and the voltage of the capacitor is lowered, the voltage in the LED light emitting region shown in FIG. 8A is always applied between the electrodes of the LED. As a result, the amount of light emitted from each LED is sufficiently secured, and the emission color of the flash light can be corrected more effectively.

  Here, if all the three LEDs 114r, 114g, and 114b are made to emit light at the same time, the amount of emitted light of the most necessary emission color (red or green or blue) is sufficient to correct the emission color of the flash light. You may not be able to get it.

  In view of such a situation, in order to secure the light emission amount of the light emission color necessary for correcting the light emission color of the flash light, the LED 114g emitting green light is first emitted, and then the capacitor MC is sufficiently used as the next LED. Light necessary for color correction may be emitted while a large amount of power is accumulated.

  FIG. 9 is a diagram illustrating a configuration example when light is emitted sequentially from an LED having a large light emission amount in the current photographing.

  FIG. 9A shows a diagram similar to FIG. 7, and FIG. 9B shows a configuration in which a changeover switch SW2 is added in addition to the configuration of FIG. 8B. ing.

  With such a configuration, the LED 114g having a large light emission amount is first selected by the switch SW2 in the current photographing to emit light, and then the LEDs 114r and 114b are sequentially emitted by switching the switch SW2. Further, the voltage applied between the electrodes of the LED (114roll114gor114b) that emits light by switching the switch SW1 toward a smaller resistance value as the voltage of the main capacitor MC decreases is shown in FIG. It is possible to secure a certain amount of light emitted from the LEDs 114r, 114g, and 114b so as to be maintained within the light emitting region shown in a).

  In other words, while the capacitor MC still has power reserve, the LED 114r 114gor 114b having the light emission color most necessary for correction is emitted with a sufficient amount of light emission, and the priority is not so high, but it is finer if the light is emitted. Even if the light that can be corrected is sequentially emitted and the voltage of the main capacitor decreases with time, a certain amount of emitted light is secured for the necessary light.

  As described above, an imaging apparatus including a light emitting unit that can correct the emission color of flash light emitted from a xenon tube or the like to a color corresponding to the color temperature of the object scene is realized.

It is a figure which shows the external appearance of the digital camera 1 which is one Embodiment of this invention. FIG. 2 is a configuration block diagram showing an internal configuration of the digital camera 1 in FIG. 1. 4 is a flowchart illustrating a procedure of photographing processing with flash light performed by a system control circuit 110. It is a flowchart which shows the process sequence at the time of making it light-emit to LED after the exposure start by this imaging | photography from the start of exposure by this imaging | photography, and making a xenon tube light-emit during exposure after that. It is a figure explaining another embodiment. FIG. 6 is a diagram showing a configuration in a drive circuit 1130 shown in FIG. 5. It is a figure explaining that the state of the voltage which generate | occur | produced in the capacitor | condenser changes with progress of time. It is a figure explaining the example deform | transformed so that the electric power accumulate | stored in the capacitor | condenser MC could be used more effectively. It is a figure explaining the structural example when it is made to light-emit sequentially from LED with big emitted light quantity in this imaging | photography.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 100 Lens barrel 101 Finder 102 Light emission window 104 Shutter button 105 Shooting mode dial 106 Single shooting / continuous shooting switch 107 Image display ON / OFF switch 112 112A 112B Light emission amount control means 1121 Booster circuit 1122 Detection circuit 113 LED drive circuit DESCRIPTION OF SYMBOLS 1130 Drive circuit 114 Light emitting diode 115 Xenon (Xe) tube drive circuit 116 Xenon (Xe) tube MC Capacitor Bt Battery SW SW1 SW2 Changeover switch

Claims (8)

In a photographing apparatus that includes a photographing lens and an image sensor, forms an image of a subject on the image sensor with the photographing lens, and generates an image signal with the image sensor.
A color temperature detector that detects a color temperature of the object scene based on an image signal generated by the image sensor;
A first light emitting unit that emits flash light toward a subject and that cannot adjust the emission color;
A second light-emitting unit that emits light having a color temperature adjusted toward the subject and that can adjust the emission color;
In synchronization with shooting, the first light emitting unit emits flash light, and the second light emitting unit corresponds to the color temperature detected by the color temperature detecting unit when combined with the flash light. An imaging apparatus comprising: a light emission control unit that emits light of a color irradiated with light of a color to a subject.   The light emission control unit is configured to cause the second light emitting unit to emit light from before the start of exposure by the current photographing to after the start of exposure by the current photographing, and then to cause the first light emitting unit to emit light during the exposure. The imaging device according to claim 1.   The power storage capacitor is provided, and both the first light emitting unit and the second light emitting unit emit light upon receiving the supply of power stored in the capacitor. Shooting device.   4. The photographing apparatus according to claim 3, wherein the light emission control unit is configured to first cause the first light emitting unit to emit light and then cause the second light emitting unit to emit light during the exposure period of the current photographing. .   The second light emitting unit includes a set of a plurality of light emitting elements that respectively emit a plurality of colored lights, and the light emission control unit sequentially supplies the plurality of light emitting elements to the second light emitting unit. The photographing apparatus according to claim 4, wherein the photographing apparatus emits light.   6. The photographing apparatus according to claim 5, wherein the light emission control unit causes the second light emitting unit to sequentially emit light from a light emitting element having a large light emission amount in the current photographing.   The photographing apparatus according to claim 1, wherein the first light emitting unit includes a xenon tube and causes the xenon tube to emit flash light.   The imaging apparatus according to claim 1, wherein the second light emitting unit includes an LED that emits light whose emission color is adjustable, and causes the LED to emit light.

Images