JP4374863B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus including an illumination device that can be used for moving image shooting.
[0002]
[Prior art]
In recent years, compact digital still cameras have become multifunctional, and not only a still image shooting function but also a moving image shooting function is increasing. In general, many compact digital still cameras are equipped with a strobe in the camera body. When the amount of exposure is insufficient such as at night, the strobe is fired to take a picture.
[0003]
However, since the strobe of a conventional digital still camera uses a xenon tube as a light source, it can emit only instantaneous light and cannot be used for moving image shooting. For this reason, when taking a moving picture with a digital still camera at night or the like, it was necessary to shoot using a video light in the same way as with a digital video camera.
[0004]
Therefore, in order to eliminate such disadvantages during movie shooting, one movie can be used for both still image shooting and movie shooting by shooting the flash in synchronization with the vertical sync signal during movie shooting. It has been proposed (for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-76891 A
[0006]
[Problems to be solved by the invention]
However, since the strobe light from the xenon tube is instantaneous light, even if the strobe light is emitted in synchronization with the vertical sync signal, it can only be irradiated for a moment during the exposure period, and the captured image is unnatural. There is a drawback of becoming.
[0007]
In addition, since the strobe light from the xenon tube has almost the same color temperature as sunlight during the daytime, it becomes unnatural when shooting with a strobe in the evening, and the atmosphere at the time of shooting is impaired. .
[0008]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an imaging apparatus that can perform moving image shooting with natural depiction using illumination light.
[0013]
[Means for Solving the Problems]
ContractClaim1In order to achieve the above object, according to the present invention, as a shooting mode, a still image shooting mode for capturing an image captured by an image sensor and recording it as a still image data on a recording medium, and an image captured by the image sensor Are continuously captured at a predetermined cycle and recorded in the recording medium as moving image data, and still image shooting and moving image shooting can be selectively performed by switching the shooting mode. In the imaging apparatus, based on the brightness of the subject measured by the light metering means, the illumination means using the light emitting diode as a light source, the light metering means for measuring the brightness of the subject, and the subject brightness measured by the light metering means. At the time of imagingAperture value, shutter speedAnd means for controlling light emission of the light emitting diode in a still image shooting mode, starting light emission of the light emitting diode in synchronization with exposure of the imaging device, and emitting the light when a necessary amount of light is emitted. Means for stopping the light emission of the diode, and means for controlling the light emission of the light emitting diode in the moving image shooting mode, the means for controlling the light emitting diode to emit light in synchronization with an exposure period of the image sensor. Provided is an imaging apparatus characterized by comprising the above.
[0014]
  According to the present invention, light having the same color temperature as the color temperature of the object scene is emitted in synchronization with the exposure period so as to compensate for the insufficient light amount with respect to the appropriate exposure amount. Thereby, a natural and homogeneous image can be obtained without impairing the atmosphere during photographing. In addition, power consumption can be suppressed by emitting light only during the exposure period.
  Claims2In order to achieve the above object, according to the present invention, as a shooting mode, a still image shooting mode for capturing an image captured by an image sensor and recording it as a still image data on a recording medium, and an image captured by the image sensor Are continuously captured at a predetermined cycle and recorded in the recording medium as moving image data, and still image shooting and moving image shooting can be selectively performed by switching the shooting mode. In the imaging apparatus, means for determining a set shooting mode, illumination means using light emitting diodes of RGB three colors as a light source, photometry means for measuring the brightness of the subject, and color for measuring the color temperature of the object field Measured by a temperature measuring means, a computing means for calculating an insufficient light amount with respect to an appropriate exposure amount of the image sensor based on a measurement result of the photometric means, and a photometric means. At the time of imaging it was based on the brightness of the subjectAperture value, shutter speedAnd means for controlling the light emission of the light emitting diode in the still image shooting mode, starting the light emission of the light emitting diode in synchronization with the exposure of the imaging device, and measuring the color temperature during light emission. Means for controlling the ratio of the light emission amounts of the respective light emitting diodes so that the color temperature is measured by the means, and stopping the light emission of the light emitting diodes when the required amount of light is emitted; A means for controlling light emission, wherein the light emission amount of each of the light emitting diodes is controlled so that the insufficient light amount calculated by the arithmetic means is emitted, and the color temperature measured by the color temperature measurement means is obtained; The light emitting diode emits light in synchronism with the exposure period of the image sensor. To provide an imaging apparatus characterized by comprising a means for controlling so.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of an imaging apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a block diagram showing the configuration of a digital still camera to which the present invention is applied. This digital still camera 10 has both still and moving image shooting functions, and by switching a shooting mode (still image shooting mode or moving image shooting mode) with a mode switch (not shown), still image shooting is performed. And video shooting can be selectively performed.
[0017]
Image light indicating a subject is imaged on a light receiving surface of an image pickup device (CCD) 16 through a photographing lens 12 and a diaphragm 14. A large number of photosensors are arranged in a plane on the light receiving surface of the CCD 16, and the subject image formed on the light receiving surface is converted into a signal charge of an amount corresponding to the amount of incident light by each photosensor, Accumulated.
[0018]
The signal charge of the image accumulated in each photosensor is output to the shift register by the read gate pulse applied from the CCD drive circuit 18, and is sequentially output as a voltage signal corresponding to the signal charge by the register transfer pulse.
[0019]
The CCD 16 can sweep out signal charges accumulated in each photosensor by applying a shutter gate pulse from the CCD drive circuit 18, thereby controlling the charge accumulation time (exposure time) ( So-called electronic shutter function).
[0020]
The voltage signal of the image sequentially read out from the CCD 16 is applied to a correlated double sampling circuit (CDS circuit) 20, where the R, G and B signals for each pixel are sampled and held, and an A / D converter 22 is obtained. Added to.
[0021]
The A / D converter 22 converts analog R, G, and B signals sequentially added from the CDS circuit 20 into digital R, G, and B signals and outputs them. The digital R, G, B signals output from the A / D converter 22 are temporarily stored in the memory 126 and then added to the digital signal processing circuit 28.
[0022]
The CCD drive circuit 18, the CDS circuit 20, and the A / D converter 22 are driven in synchronization with a timing signal applied from the timing generation circuit 24.
[0023]
The digital signal processing circuit 28 includes a synchronization circuit 30, a white balance adjustment circuit 32, a gamma correction circuit 34, a YC signal generation circuit 36, a memory 38, and the like.
[0024]
The synchronization circuit 30 converts the dot-sequential R, G, and B signals read from the memory 26 into a simultaneous expression, and outputs the R, G, and B signals to the white balance adjustment circuit 32 at the same time.
[0025]
The white balance adjustment circuit 32 includes multipliers 32R, 32G, and 32B for increasing and decreasing the digital values of the R, G, and B signals, respectively. The R, G, and B signals output from the synchronization circuit 30 are added to the multipliers 32R, 32G, and 32B. A white balance correction value (gain value) for white balance control is added from the central processing unit (CPU) 40 to other inputs of the multipliers 32R, 32G, and 32B. The multipliers 32R, 32G, and 32B The white balance correction is performed by multiplying the white balance correction value by the R, G, and B signals output from the synchronization circuit 30. Then, the R, G, and B signals subjected to white balance correction are output to the gamma correction circuit 34.
[0026]
The gamma correction circuit 34 changes the input / output characteristics so as to obtain a desired gamma characteristic for the R, G, and B signals that have undergone white balance correction, and outputs them to the YC signal generation circuit 36.
[0027]
The YC signal creation circuit 36 creates a luminance signal Y and chroma signals Cr, Cb from the gamma-corrected R, G, B signals. The luminance signal Y and chroma signals Cr and Cb (YC signal) are stored in the memory 38 in the same memory space as the memory 26. By reading the YC signal in the memory 38 and outputting it to the liquid crystal monitor 42, a through image is displayed on the liquid crystal monitor 42.
[0028]
Here, when the release button of the camera operation unit 44 is pressed while the camera mode is set to the still image shooting mode, still image shooting is performed, and YC data of the main image is stored in a predetermined area of the memory 38. Is done. The YC data of the main image is compressed into a predetermined format by the compression / decompression processing circuit 46 and then recorded on a recording medium such as a memory card by the recording unit 48.
[0029]
In addition, when the release button of the camera operation unit 44 is pressed while the camera mode is set to the moving image shooting mode, moving image shooting is started, and YC data from the YC signal generation circuit 36 is transmitted at a predetermined cycle (for example, 30 per second). Frame) to be taken into a predetermined area of the memory 38. The YC data captured in the memory 38 is compressed at a rate of once every three times and stored in a predetermined area of the memory 38. When the release button is pressed again, the moving image shooting ends, and the YC data of the moving image compressed and stored in a predetermined area of the memory 38 at this time is recorded on the recording medium by the recording unit 48.
[0030]
The CPU 40 comprehensively controls each circuit based on input information from the camera operation unit 44 including a mode switch, a release button, a cross button, and the like, as well as autofocus (AF) control, automatic exposure (AE) control, white balance ( AWB) and other controls are performed.
[0031]
Here, the AF control is, for example, contrast AF for moving the photographing lens 12 so that the high frequency component of the G signal is maximized, and a lens (not shown) so that the high frequency component of the G signal is maximized when the release button is half-pressed. The taking lens 12 is moved to the in-focus position via the drive unit.
[0032]
In the AE control, R, G, and B signals are captured, and the brightness of the subject (imaging EV value) is obtained based on an integrated value obtained by integrating these R, G, and B signals, and based on the captured EV value. The aperture value and shutter speed at the time of imaging are determined. At this time, if the photographing light quantity is insufficient, strobe light is emitted from the strobe device 60.
[0033]
In the AWB control, the light source type (color temperature) of the object scene is measured, and white balance correction is performed according to the measured light source type. The measurement of the light source type of the object scene is performed as follows.
[0034]
That is, one screen is divided into a plurality of areas (for example, 64 areas of 8 × 8) from the R, G, and B signals, and an average integrated value for each color of the R, G, and B signals is obtained for each area. The average integrated values of the R, G, and B signals for each of these divided areas are calculated by the integrating circuit 52 and added to the CPU 40. Multipliers 52R, 52G, and 52B are provided between the integrating circuit 50 and the CPU 40, and an adjustment gain value for adjusting variation of the devices is added to the multipliers 52R, 52G, and 52B. The CPU 40 determines the type of light source such as daylight (clear), shade-cloudy, fluorescent lamp, tungsten bulb, etc., based on the average integrated value of the R, G, B signals for each divided area.
[0035]
This light source type is determined by obtaining ratios R / G and B / G of average integrated values for each color of the R, G, and B signals for each divided area, followed by R / G on the horizontal axis and B / on the vertical axis. On the graph of G, a detection frame indicating a color distribution range corresponding to each light source type is set. Then, the number of areas entering the detection frame is obtained based on the ratios R / G and B / G for each area thus obtained, and the light source type is determined based on the luminance level of the subject and the number of areas entering the detection frame ( (See JP 2000-224608).
[0036]
When the CPU 40 determines the light source type (color temperature of the object scene) as described above, the CPU 40 determines a white balance correction value suitable for the light source type, and a multiplier for the determined white balance correction value (gain value). Output to 32R, 32G, 32B. As a result, the R, G, and B signals subjected to white balance adjustment are output to the gamma correction circuit 34 from the multipliers 32R, 32G, and 32B.
[0037]
The strobe device 60 is configured by using a light emitting diode (LED) as a light source, and causes the RGB three-color light emitting diodes to emit light to emit high-intensity white light.
[0038]
FIG. 2 is a cross-sectional view illustrating a configuration of the light emitting unit of the strobe device 60. As shown in the figure, the light emitting unit of the strobe device 60 includes RGB three-color LEDs 62R, 62G, and 62B (hereinafter, the three-color LEDs 62R, 62G, and 62B are referred to as LED groups 62 as necessary), a reflector 64, It comprises a diffusion plate 66.
[0039]
The RGB three-color LEDs 62R, 62G, and 62B are mounted on the circuit board 68, respectively. The reflector 64 is attached to the circuit board 68 so as to surround the LED group 62 and reflects light emitted from the LED group 62 forward. The diffuser plate 66 is integrally attached to the inside of the reflector 64 and diffuses highly directional light emitted from the LED group 62.
[0040]
FIG. 3 is a block diagram showing the configuration of the strobe device 60. As shown in the figure, RGB three-color LEDs 62R, 62G, and 62B that are strobe light sources are connected in parallel to a main capacitor 70, and current is supplied from the main capacitor 70.
[0041]
Further, transistors 72R, 72G, and 72B are connected to the LEDs 62R, 62G, and 62B, respectively, and a pulse signal whose ON / OFF duty ratio is controlled is added to the bases of the transistors 72R, 72G, and 72B. The current flowing from the main capacitor 70 to the LEDs 62R, 62G, and 62B is controlled. That is, the transistors 72R, 72G, and 72B allow current to flow from the main capacitor 70 to the LEDs 62R, 62G, and 62B only during the ON period of the pulse signal applied to the base, and interrupt the current during the OFF period. Thereby, the electric current which flows into each LED62R, 62G, 62B is controlled, and the light emission amount of each LED62R, 62G, 62B is controlled. The CPU 40 controls the light emission time of each LED 62R, 62G, 62B by controlling the ON / OFF duty ratio of the pulse signal applied to the base of each transistor 72R, 72G, 72B. Control the color temperature.
[0042]
FIG. 4 shows a timing chart in the case where the ON / OFF duty ratio of each LED 62R, 62G, 62B is adjusted to control the color temperature of the strobe light (ratio of light emission amounts of R, G, B). That is, the ON / OFF duty ratio of the LEDs 62R, 62G, and 62B is determined so that the ratio of the ON times of the LEDs 62R, 62G, and 62B becomes the ratio of the light emission amounts of R, G, and B (in FIG. 4, R The case where the ON / OFF duty ratio of the LEDs 62R, 62G, and 62B is set assuming that the ratio of the light emission amounts of G, B is 1: 2: 3 is illustrated). As a result, strobe light adjusted to a predetermined color temperature as a whole is emitted.
[0043]
The main capacitor 70 is charged via the power supply circuit 74, and the power supply circuit 74 boosts the voltage of the battery 76 loaded in the camera to a predetermined voltage to charge the main capacitor 70. The power supply to each circuit constituting the system is also performed through the power supply circuit 74, and the CPU 40 controls the power supply circuit 74 to control the power supply to each circuit.
[0044]
In addition, the dimming control of the strobe light at the time of still image shooting is performed via the dimming circuit 78, and the dimming circuit 78 outputs a light emission stop signal to the CPU 40 when a predetermined amount of strobe light is emitted. That is, when strobe light is emitted from the LED group 62, strobe reflected light is received via the strobe light receiving sensor 80, and if the amount of received light matches a preset reference value, the light control is performed. The circuit 78 outputs a light emission stop signal to the CPU 40. When receiving the light emission stop signal, the CPU 40 interrupts the current flowing through the LED group 62 and stops the light emission of the LED group 62. The CPU 40 outputs a light emission amount adjustment reference value for obtaining a desired strobe light emission amount to the dimming circuit 78 in the strobe light emission.
[0045]
FIG. 5 is a flowchart showing a procedure of LED light emission control during flash photography.
[0046]
As shown in the figure, first, the shooting mode is determined (step S10). That is, it is determined whether the set shooting mode is the still image shooting mode or the moving image shooting mode. This determination is made based on the output from the mode selector switch of the camera operation unit 44.
[0047]
When the still shooting mode is set, first, it is determined whether or not the release button is half-pressed (switch S1 is ON) (step S12). When the switch S1 is turned ON, the process proceeds to step S14 and AE, AF, AWB control is performed. That is, the brightness of the subject (shooting EV value) is measured, and the aperture value and shutter speed (charge accumulation time) are determined from the measured shooting EV value. Further, the photographing lens 12 is driven so that the main subject is focused based on the contrast information of the subject. In addition, the color temperature of the object scene is measured, the white balance correction value is determined, and the ON / OFF duty of each LED 62R, 62G, 62B necessary for emitting light having the same color temperature as that color temperature is determined. The ratio is determined.
[0048]
Subsequently, it is determined whether or not the release button is fully pressed (switch S2 is ON) (step S16). When switch S2 is ON, shooting is performed with the aperture value and shutter speed determined in step S14. . In synchronism with this exposure, the strobe device 60 having the same color temperature as the color temperature of the object scene emits light. That is, a pulse signal whose duty ratio is controlled so that light having the same color temperature as that of the object scene obtained in step S14 is emitted from the LED group 62 is added to the bases of the transistors 72R, 72G, and 72B. A current is passed through each of the R, G, and B LEDs 62R, 62G, and 62B.
[0049]
When the LED group 62 starts to emit light, dimming control is performed, and it is determined whether or not the light amount incident on the light receiving sensor 80 has reached a predetermined light amount (step S20). That is, it is determined whether or not a light emission OFF signal (dimming OK) is issued from the light control circuit 78. When a light emission OFF signal is issued, the current supply to the LED group 62 is stopped and light emission is stopped ( Step S22). On the other hand, if the light control is not OK, it is determined whether or not the exposure time has passed (step S24), and the light emission of the LED group 62 is also stopped when the exposure time has passed before the light control is completed.
[0050]
As described above, when shooting with the flash in the still image shooting mode, shooting is performed by emitting the flash light having the same color temperature as the object scene. Thereby, flash photography can be performed without impairing the atmosphere during photography.
[0051]
On the other hand, in the moving image shooting mode, the flash emission is controlled as follows. That is, when it is determined in step S10 that the camera mode is the moving image shooting mode, it is first determined whether or not the release button is fully pressed (switch S2 is ON) (step S26).
[0052]
When the switch S2 is turned on, the process proceeds to step S28 where the color temperature of the object scene is measured (step S28), and the LEDs 62R, 62G necessary for emitting light having the same color temperature as that color temperature are measured. , 62B ON / OFF duty ratio is determined.
[0053]
Thereafter, recording is started, and strobe light adjusted to the same color temperature as the object scene is emitted with a constant light amount at the start of recording (step S30). That is, a pulse signal whose duty ratio is controlled is applied to the bases of the transistors 72R, 72G, and 72B, and a current flows from the main capacitor 70 to the LEDs 62R, 62G, and 62B. Thereby, light having the same color temperature as the color temperature of the object scene is emitted from the LED group 62.
[0054]
The strobe light is emitted in synchronism with the exposure period of the CCD 16 and is emitted only during the exposure period of the CCD 16 (current is supplied to the LEDs 62R, 62G, and 62B only during the exposure period of the CCD 16). More specifically, the light emission is controlled as follows.
[0055]
FIG. 6 is a timing chart of the light emission control of the strobe device during moving image shooting. In the figure, (a) is the ON signal of the switch S2, (b) is the color temperature reading period, (c) is the recording period, (d) is the CCD exposure period, and (e) is the strobe light emission period. Show.
[0056]
As shown in FIG. 6, when the ON signal of the switch S2 is input, the color temperature of the external light is measured, and then recording is started. Simultaneously with the start of recording, the CCD 16 is exposed at a constant cycle, and the flash device 60 emits light in synchronization with the exposure period of the CCD 16. Thereby, useless light emission can be prevented and power saving can be achieved. In addition, since the strobe light is always emitted during the exposure period, it is possible to perform moving image shooting without unnaturalness.
[0057]
Thus, strobe light is emitted in synchronization with the exposure period of the CCD 16 during recording. Then, during the recording, it is determined whether or not the release button is fully pressed (switch S2 is ON) (step S32). When the switch S2 is turned ON, the recording is stopped and the current supply to the LED group 62 is performed. The light emission is stopped (step S22).
[0058]
As described above, the digital still camera 10 of the present embodiment can use one strobe device 60 for both still image shooting and moving image shooting. And since it can shoot by emitting light having the same color temperature as the color temperature of the object field at each shooting, it is possible to shoot without impairing the atmosphere at the time of shooting.
[0059]
Further, when shooting moving images, strobe light is emitted in synchronization with the exposure period of the CCD 16, thereby eliminating unnecessary light emission and saving power. Further, since the strobe light is always emitted during the exposure period, it is possible to perform moving image shooting without unnaturalness.
[0060]
In this embodiment, the color temperature of the strobe light is adjusted to the same color temperature as the color temperature of the object scene during moving image shooting. However, a constant color temperature (for example, daytime sunlight ( Strobe light having the same color temperature as that of the daylight) may be emitted in synchronization with the exposure period of the CCD 16. In this case, it is not always necessary to use RGB three-color LEDs as the strobe light source, and LEDs that emit white light with high brightness may be used as the strobe light source.
[0061]
In the present embodiment, the strobe light having a constant light amount is emitted during moving image shooting, but only the insufficient light amount with respect to the appropriate exposure amount may be emitted. That is, when photographing with a predetermined aperture value and shutter speed, the insufficient light amount with respect to the appropriate exposure amount is calculated based on the photometric result (photographing EV value), and the strobe device 60 is caused to emit light by the insufficient light amount. Good. Thereby, useless light emission can be prevented and power saving can be achieved. At this time, by shooting the strobe light having the same color temperature as the color temperature of the object scene, it is possible to perform moving image shooting without impairing the atmosphere during shooting.
[0062]
In the present embodiment, the light control of the strobe light is performed via the light control circuit 78 during still image shooting. However, the light emission amount is determined in advance based on the brightness of the subject and the subject distance. The light emission control of the LED group 62 may be performed so that the emitted light amount is emitted within the exposure time (shutter speed time).
[0063]
Furthermore, in the present embodiment, the strobe light source is configured by using one RGB three-color LED one by one, but the number of LEDs installed is not limited to this. Further, the numbers of R, G, B, and LEDs need not be the same, and may be arranged at a ratio such that white light is obtained when full light is emitted.
[0064]
FIG. 7 is a block diagram showing a configuration of the strobe device according to the second embodiment. In the strobe device of the present embodiment, the amount of current flowing through each LED is controlled by an operational amplifier. In addition, the same code | symbol is attached | subjected to the same component as the strobe device of embodiment mentioned above, and the description is abbreviate | omitted.
[0065]
As shown in FIG. 7, the RGB three-color LEDs 62R, 62G, and 62B that are strobe light sources are connected in parallel to the main capacitor 70, and current is supplied from the main capacitor 70 through operational amplifiers 82R, 82G, and 82B. . The CPU 40 controls the operational amplifiers 82R, 82G, and 82b, and controls the light emission amount and the light emission time of the R, G, and B LEDs 62R, 62G, and 62B.
[0066]
That is, the CPU 40 emits light from each of the R, G, and B LEDs 62R, 62G, and 62B so that the light having the same color temperature is emitted from the strobe device based on the measurement result of the color temperature of the object scene when the flash is emitted. Determine the ratio. Then, R, G, and B light emission levels corresponding to this ratio are set, and control signals indicating the R, G, and B light emission levels are output to the positive inputs of the operational amplifiers 82R, 82G, and 82B. Signals corresponding to the current values flowing through the LEDs 62R, 62G, and 62B are added to the negative inputs of the operational amplifiers 82R, 82G, and 82B, and the operational amplifiers 82R, 82G, and 82B have the set R, G, and B light emission levels. The constant current corresponding to is controlled so as to flow to each LED 62R, 62G, 62B. As a result, strobe light having the same color temperature as the color temperature of the object scene as a whole is emitted from the LED group 62.
[0067]
Further, during moving image shooting, the operational amplifiers 82R, 82G, and 82B are controlled so that strobe light is emitted in synchronization with the exposure period of the CCD.
[0068]
In this way, the color temperature of the strobe light can be adjusted by controlling the amount of current flowing through the LEDs 62R, 62G, and 62B by the operational amplifiers 82R, 82G, and 82B, and synchronized with the exposure period of the CCD. Can be emitted.
[0069]
In the series of embodiments described above, the case where the strobe device is incorporated in the camera body has been described as an example. However, the present invention can also be applied to a type of camera in which the strobe device is externally attached to the camera body. it can.
[0070]
In the series of embodiments described above, the case where the present invention is applied to a digital still camera has been described as an example. However, the present invention can be similarly applied to a video camera. In this case, the video camera may have both a still image shooting function and a moving image shooting function, or only a moving image shooting function. Note that, as in the present embodiment, by applying the present invention to a digital still camera, one strobe device can be used for shooting both still images and moving images.
[0071]
【The invention's effect】
As described above, according to the present invention, since light is emitted from the light emitting diode in synchronization with the exposure period, useless light emission can be prevented and power saving can be achieved. In addition, by always emitting light during the exposure period, it is possible to perform moving image shooting without unnaturalness.
[0072]
In addition, according to the present invention, light having the same color temperature as the color temperature of the object scene is emitted so as to compensate for the insufficient light amount with respect to the appropriate exposure amount, so that a natural image can be obtained without impairing the atmosphere during shooting. Obtainable.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a digital still camera to which the present invention is applied.
FIG. 2 is a cross-sectional view showing a configuration of a light emitting unit of a strobe device
FIG. 3 is a block diagram showing the configuration of a strobe device
FIG. 4 is a timing chart in the case of controlling the color temperature of the strobe light (ratio of light emission amounts of R, G, B) by adjusting the ON / OFF duty ratio of each LED of R, G, B.
FIG. 5 is a flowchart showing a procedure of LED light emission control during flash photography.
FIG. 6 is a timing chart of light emission control of the strobe device during moving image shooting.
FIG. 7 is a block diagram illustrating a configuration of a strobe device according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Digital still camera, 12 ... Shooting lens, 14 ... Aperture, 16 ... Imaging device (CCD), 18 ... CCD drive circuit, 20 ... Correlated double sampling circuit (CDS circuit), 22 ... A / D converter, 24 ... Timing generation circuit, 26 ... Memory, 28 ... Digital signal processing circuit, 30 ... Synchronization circuit, 32 ... White balance adjustment circuit, 32R, 32G, 32B ... Multiplier, 34 ... Gamma correction circuit, 36 ... YC signal generation circuit , 38 ... Memory, 40 ... Central processing unit (CPU), 42 ... Liquid crystal monitor, 44 ... Camera operation unit, 46 ... Compression / decompression processing circuit, 48 ... Recording unit, 50 ... Integration circuit, 52R, 52G, 52B ... Multiplier , 60 ... Strobe device, 62 ... LED group, 62R, 62G, 62B ... Light emitting diode (LED), 64 ... Reflector, 66 ... Diffuser, 68 ... Circuit group , 70 ... main capacitor, 72R, 72G, 72B ... transistor, 74 ... power supply circuit, 76 ... battery, 78 ... light control circuit, 80 ... light-receiving sensor, 82R, 82G, 82B ... op

Claims (2)

As a shooting mode, a still image shooting mode in which an image captured by an image sensor is captured and recorded on a recording medium as still image data, and an image captured by the image sensor is continuously captured at a predetermined cycle, and is recorded as moving image data. In an imaging apparatus having a moving image shooting mode for recording on the recording medium, and capable of selectively performing still image shooting and moving image shooting by switching the shooting mode,
Means for determining the set shooting mode;
Illumination means using a light emitting diode as a light source;
A photometric means for measuring the brightness of the subject;
Means for determining an aperture value and shutter speed at the time of imaging based on the brightness of the subject measured by the photometric means;
A means for controlling light emission of the light emitting diode in a still image shooting mode, starting light emission of the light emitting diode in synchronization with exposure of the image sensor, and stopping light emission of the light emitting diode when a necessary amount of light is emitted. Means,
Means for controlling light emission of the light emitting diode during the moving image shooting mode, and means for controlling the light emitting diode to emit light in synchronization with an exposure period of the imaging element;
An imaging apparatus comprising: As a shooting mode, a still image shooting mode in which an image captured by an image sensor is captured and recorded on a recording medium as still image data, and an image captured by the image sensor is continuously captured at a predetermined cycle, and is recorded as moving image data. In an imaging apparatus having a moving image shooting mode for recording on the recording medium, and capable of selectively performing still image shooting and moving image shooting by switching the shooting mode,
Means for determining the set shooting mode;
Illumination means using light emitting diodes of RGB three colors as a light source;
A photometric means for measuring the brightness of the subject;
Color temperature measuring means for measuring the color temperature of the object field;
An arithmetic unit that calculates an insufficient light amount with respect to an appropriate exposure amount of the image sensor based on a measurement result of the photometric unit;
Means for determining an aperture value and shutter speed at the time of imaging based on the brightness of the subject measured by the photometric means;
Means for controlling the light emission of the light emitting diode in a still image shooting mode, wherein the light emission of the light emitting diode is started in synchronism with the exposure of the imaging device, and the color measured by the color temperature measuring means during light emission; Means for controlling the ratio of the amount of light emission of each light emitting diode so as to become temperature, and stopping the light emission of the light emitting diode when a necessary amount of light is emitted;
Means for controlling the light emission of each light emitting diode in the moving image shooting mode, controlling the light emission amount of each light emitting diode so that the insufficient light amount calculated by the computing means is emitted, and measuring the color temperature Means for controlling the ratio of the light emission amounts of the respective light emitting diodes so as to achieve the color temperature measured by the means, and for controlling the light emitting diodes to emit light in synchronization with the exposure period of the imaging device;
An imaging apparatus comprising:

Images