JP5803406B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging device.

  Conventionally, an imaging device equipped with a photometric device, such as calculating the luminance of a subject using an output signal of a photometric sensor and controlling exposure during shooting, or analyzing and analyzing a shooting scene to determine and recognize a subject It has been known. As a photometric device used for such an image pickup device, a CCD (Charge Coupled Device) image sensor which is a photoelectric conversion element is generally used in consideration of the necessity of accumulating charges along with flash light emission. This CCD image sensor has an advantage that the power consumption can be suppressed as a result, since the number of pixels is small and the number of operation clocks is small.

  Recently, not only an image sensor but also a photometric sensor has a tendency to increase the number of pixels. Here, when the number of pixels of the CCD image sensor is increased, there is a disadvantage that the signal readout time becomes longer, and it is also considered to use a CMOS (Complementary Metal Oxide Semiconductor) image sensor instead of a CCD image sensor as a photometric sensor. Has been. Since the CMOS image sensor can perform A / D conversion and output inside the sensor, there are advantages that analog noise can be reduced and signal readout time can be reduced. In addition, there is an advantage that the accuracy of photometry and scene analysis can be improved using a signal from the photometric sensor.

JP 2011-2688 A

  However, the CMOS image sensor needs to be driven at a higher speed than the CCD image sensor due to the difference in the number of pixels, and as a result, the power consumption is greatly increased. For this reason, when a CMOS image sensor is used as a photometric sensor, there is a disadvantage that a battery that is attached to the digital camera has a poor holding time and a large number of images cannot be acquired.

An object of the present invention is to provide an imaging apparatus capable of suitable imaging control .

In order to solve the above-described problem, the imaging apparatus according to the present embodiment has a plurality of pixels, and calculates the first output signal output from the plurality of pixels when calculating the exposure by the exposure calculation unit that calculates the exposure. When the light emission amount is calculated by the light emission amount calculation unit that outputs to the exposure calculation unit and calculates the light emission amount, the second output signal output from the plurality of pixels is output to the light emission amount calculation unit, and the suppression signal is supplied. And an imaging unit that suppresses power supply to the plurality of pixels when the operation is performed, a first accumulation operation by the plurality of pixels for outputting the first output signal, and after the first accumulation operation. By the plurality of pixels for outputting the suppression signal to the imaging unit and outputting the second output signal during the second accumulation operation by the plurality of pixels for outputting the first output signal A third accumulation operation; And a said not output the inhibition signal to the imaging unit control section between the fourth holding operation by the plurality of pixels for outputting the second output signal is carried out after the accumulation operation.

The imaging apparatus according to the present embodiment includes a plurality of pixels, and outputs an output signal output from the plurality of pixels to an exposure calculation unit that calculates exposure and a light emission amount calculation unit that calculates light emission amount. A first accumulation operation by the plurality of pixels for outputting the output signal to the imaging unit and the exposure calculation unit, and the output signal is output to the exposure calculation unit performed after the first accumulation operation For controlling the power supply to the plurality of pixels during the second accumulation operation by the plurality of pixels for outputting the output signal to the light emission amount calculation unit. To the plurality of pixels between a third accumulation operation and a fourth accumulation operation by the plurality of pixels for outputting the output signal to the light emission amount calculation unit performed after the third accumulation operation. Control to suppress the power supply of And a have the control unit.

ADVANTAGE OF THE INVENTION According to this invention, the imaging device in which suitable imaging control is possible can be provided .

It is a figure which shows the structure of a digital camera. It is a figure which shows the structure of a photometry sensor, a body drive control circuit, and an image processing apparatus. It is a figure which shows the structure of a photometric sensor. It is a figure which shows the structure of the pixel arrange | positioned at a photometry sensor. It is a figure which shows the timing chart of the photometry sensor in a photometry cycle. It is a figure which shows the timing chart of the photometry sensor at the time of photometry of an object scene. It is a figure which shows the timing chart of the photometry sensor at the time of TTL light control.

  FIG. 1 shows an outline of a digital camera 10 as an example of a photographing apparatus of the present embodiment. The digital camera 10 includes a camera body 11 and a lens unit 12 that can be attached to and detached from the camera body 11. The camera body 11 and the lens unit 12 are provided with a pair of mounts 13 and 14 that form a male-female relationship. When the lens unit 12 is attached to the camera body 11, the mount 14 provided on the lens unit 12 is coupled to the mount 13 of the camera body 11 by a bayonet mechanism or the like. Each of the mounts 13 and 14 is provided with an electrical contact. When the lens unit 12 is attached to the camera body 11, the electrical contacts provided on the mounts 13 and 14 come into contact with each other, and the electrical connection between them is established.

  Next, the configuration of the lens unit 12 will be described. The lens unit 12 includes an imaging optical system 21, a lens driving mechanism 22, a diaphragm 23, a diaphragm driving mechanism 24, a lens driving control circuit 25, and the like. The lens drive mechanism 22 and the aperture drive mechanism 24 are each connected to a lens drive control circuit 25.

  The imaging optical system 21 includes a plurality of lenses such as a zoom lens and a focus lens. The lenses constituting the imaging optical system 21 can be moved in the optical axis (L1) direction by the lens driving mechanism 22. The position of each lens of the imaging optical system 21 is detected by an encoder (not shown). A detection signal indicating the detected position of each lens is output to the lens drive control circuit 25. The lens drive control circuit 25 receives the input detection signal and calculates a shooting distance and a focal length at the time of shooting. These calculated values are output to the camera body 11.

  The diaphragm 23 adjusts the amount of light incident on the camera body 11 by opening and closing the diaphragm blades. The aperture driving mechanism 24 controls the opening degree of the aperture 23. The lens drive control circuit 25 communicates with the camera body 11 via the electrical contacts of the mounts 13 and 14 and executes various controls in the lens unit 12. The lens drive control circuit 25 transmits lens data recorded in a ROM (not shown) to the camera body 11.

  Incidentally, in FIG. 1, an example of a so-called single-lens reflex digital camera 10 in which the lens unit 12 is detachably attached to the camera body 11 is taken. However, the present invention is not limited to this, and the lens unit 12 is not limited to the camera body 11. It may be a so-called compact type digital camera fixed to the camera.

  Next, the configuration of the camera body 11 will be described. The camera body 11 includes a quick return mirror 31, a mechanical shutter 32, an image sensor 33, a sub mirror 34, a focus detection unit 35, a finder optical system, a photometric sensor 37, and the like.

  The quick return mirror 31, the mechanical shutter 32, and the image sensor 33 are arranged along the optical axis L <b> 1 of the image pickup optical system 21. A sub mirror 34 is disposed behind the quick return mirror 31. Further, a finder optical system and a photometric sensor 37 are arranged on the upper part of the camera body 11. Further, a focus detection unit 35 is disposed in the lower region of the camera body 11.

  The quick return mirror 31 is pivotally supported about a rotation shaft 31a and can be switched between an observation state indicated by a solid line and a retreat state retracted from the optical axis L1. The quick return mirror 31 in the observation state is inclined and disposed in front of the mechanical shutter 32 and the image sensor 33. The quick return mirror 31 in this observation state reflects the light beam that has passed through the imaging optical system 21 upward (in the direction of the optical axis L2) and guides it to the finder optical system. The central portion of the quick return mirror 31 is a half mirror, and a part of the light beam transmitted through the quick return mirror 31 is reflected downward (in the direction of the optical axis L3) by the sub mirror 34 and is reflected on the focus detection unit 35. Led. Note that the focus detection unit 35 performs so-called phase difference detection type focus detection in which an image shift amount of a subject image divided by a separator lens (not shown) is detected for each AF area. The focus detection signal from the focus detection unit 35 is output to the body drive control circuit 51.

  On the other hand, the quick return mirror 31 in the retracted state is flipped up together with the sub mirror 34 and rotated to a position off the photographing optical path. When the quick return mirror 31 is in the retracted state, the light beam that has passed through the imaging optical system 21 is guided to the mechanical shutter 32 and the imaging element 33.

  The finder optical system includes a finder screen (focus plate) 41, a condenser lens 42, a pentaprism 43, and an eyepiece lens 44. Reference numeral 45 denotes an eyepiece window. The viewfinder screen 41 is located above the quick return mirror 31. The finder screen 41 forms an image of the light beam reflected by the quick return mirror 31 in the observation state. The light beam formed on the finder screen 41 passes through the condenser lens 42 and the pentaprism 43 and is guided to the exit surface having an angle of 90 ° with respect to the incident surface of the pentaprism 43. Then, the light beam from the exit surface of the pentaprism 43 passes through the eyepiece lens 44 and then reaches the user's eyes through the eyepiece window 45.

  A part of the light beam formed on the finder screen 41 passes through the pentaprism 43 and then enters the photometric sensor 37 through the triangular prism 46 and the photometric lens 47. The photometric sensor 37 outputs a signal based on the received light beam (hereinafter, photometric signal) to the image processing circuit 55. As the photometric sensor 37, for example, a CMOS image sensor is used.

  The body drive control circuit 51 includes a microcomputer, ROM, RAM, and the like (not shown). The body drive control circuit 51 performs drive control of the image sensor 33, the photometric sensor 37, the flash device 52, the shutter drive mechanism 53, and the like. The body drive control circuit 51 performs exposure control based on the photometric calculation result and the dimming result from the image processing circuit 55, and also performs focus adjustment control based on the focus detection calculation based on the focus detection signal from the focus detection unit 35. Do. The body drive control circuit 51 communicates with the lens drive control circuit 25 via the mounts 13 and 14 to transmit and receive lens information and camera information.

  The image processing circuit 55 performs image processing such as white balance processing and gradation conversion processing on the image signal output from the image sensor 33. The image signal subjected to the image processing by the image processing circuit 55 is output to the display control circuit 56. The display control circuit 56 displays an image based on the input image signal on the display unit 57.

  The image processing circuit 55 uses the photometric signal output from the photometric sensor 37 to execute processing related to TTL light control, subject photometry, subject tracking, subject discrimination, and scene recognition, which will be described later. The result of each process is output to the body drive control circuit 51.

  As shown in FIG. 2, the body drive control circuit 51 includes a sensor drive unit 61, an exposure control unit 62, an imaging processing unit 63, and a focus control unit 64. In FIG. 2, only the portions related to exposure control and focus adjustment control are shown. The sensor driving unit 61 drives and controls the photometric sensor 37 based on the charge accumulation time and the amplifier gain set by the control calculation unit 67 described later. Since a CMOS image sensor is used as the photometric sensor 37, a rolling shutter which is a line exposure sequential readout method is used as the electronic shutter for driving control of the photometric sensor 37.

  The exposure control unit 62 performs an exposure calculation at the time of imaging based on a photometric calculation result and a dimming result output from the image processing circuit 55, and determines a shutter speed and an aperture value at the time of imaging. In addition to the shutter speed and aperture value determined by the exposure control unit 62, the imaging processing unit 63 performs imaging processing using the flash emission amount set by the TTL light control unit described later.

  The focus control unit 64 drives the lens so that the main subject is focused from the defocus amount of the focus detection area obtained from the focus detection unit 35 in addition to the position information and motion information of the subject output from the image processing circuit 55. The control circuit 25 is controlled, and the lens drive control circuit 25 moves the focus lens of the imaging optical system 21 in the optical axis (L1) direction to perform focus adjustment.

  The image processing circuit 55 includes a data processing unit 66, a control calculation unit 67, a photometry calculation unit 68, a TTL light control unit 69, a subject determination unit 70, and a subject tracking unit 71. When the photometric signal (photometric data) from the photometric sensor 37 is input, the data processing unit 66 executes processing such as pixel defect correction or blocking processing on the photometric data. The photometric data processed by the data processing unit 66 is temporarily stored in a buffer memory (not shown).

  The control calculation unit 67 executes validity determination for determining whether or not the photometric calculation is possible based on the photometric data. Further, the control calculation unit 67 sets the charge accumulation time and the amplifier gain of the photometric sensor 37 in the next photometry based on the photometric data. For example, when performing photometry of the object scene, the control calculation unit 67 sets the charge accumulation time and the amplifier gain of the photometry sensor 37 so that the maximum brightness value of the object scene becomes the target brightness value. Further, when performing scene recognition, the control calculation unit 67 sets the charge accumulation time and the amplifier gain of the photometric sensor 37 so that the average luminance value of the object scene becomes the target photometric value. Information on the charge accumulation time and amplifier gain of the photometric sensor 37 set by the control calculation unit 67 is output to the sensor driving unit 61.

  When the control calculation unit 67 determines that the photometry calculation is possible, the photometry calculation unit 68 performs the photometry calculation using the photometry data.

  The TTL light control unit 69 is based on photometric data output from the photometric sensor 37 during preliminary light emission (monitor light emission) by the flash device 52 and photometric data output from the photometric sensor 37 when the flash device 52 is not emitting light. The reflected light component at the time of monitor light emission is extracted, and the amount of flash light emission optimum for flash photography is obtained.

  The subject discrimination unit 70 executes subject discrimination processing using photometric data. Specifically, the subject determination unit 70 determines a main subject (for example, a human face region) in the image based on color information and luminance information in the photometric data, and acquires position information of the determined subject. Note that when a person's face area is determined, a face detection sequence such as, for example, extracting a human face feature amount or specifying a skin color area may be used. The discrimination result (subject position information) in the subject discrimination unit 70 is output to the body drive control circuit 51 in addition to the photometry calculation unit 68 and the TTL dimming unit 69.

  The subject tracking unit 71 uses the focus detection area selected by the user to execute subject tracking processing by a template matching method, for example. By executing the subject tracking process by the subject tracking unit 71, the movement information of the subject is acquired. The subject movement information acquired by the subject tracking unit 71 is output to the body drive control circuit 51.

  Next, the photometric sensor 37 will be described. The photometric sensor 37 is composed of a CMOS image sensor provided with a primary color transmission filter (not shown) on the front surface. This primary color transmission filter is, for example, a primary color Bayer in which the resolution of G (green) is N / 2 and the resolution of R (red) and B (blue) is N / 4 with respect to the total number N of pixels of the photometric sensor 37. It is an array (not shown).

  As shown in FIGS. 3 and 4, the CMOS image sensor includes a plurality of pixels P (i, j), a timing generator (TG) 75, a reset circuit 76, a vertical scanning circuit 77, and a horizontal scanning arranged in a two-dimensional manner. A circuit 78, a CDS circuit 79, an AD converter (ADC) 80, and the like are provided. 3 and 4 show an example of the configuration of the CMOS image sensor, and the configuration of FIGS. 3 and 4 is not necessarily required.

  The plurality of pixels P (i, j) includes a photodiode (PD) 81, a floating diffusion (FD) 82, an amplification transistor 83, a row selection transistor 84, and a reset transistor 85.

  The PD 81 is connected to the gate of the amplification transistor 83, and the amplification transistor 83 generates a signal (pixel signal) corresponding to the amount of charge accumulated in the FD 82. The FD 82 is connected to the power supply voltage Vdd via the reset transistor 85.

For example, when the reset transistor 85 by the control signal .phi.R _n output from the reset circuit 73 is ON, the charge accumulated in the PD81 and FD82 are cleared. After the charges accumulated in the PD 81 and the FD 82 are cleared, the received light beam is converted into charges by the PD 81 and transferred from the PD 81 to the FD 82. When the control signal ΦS _n is output in response to the vertical synchronization signal output when the charge accumulation time has elapsed, the row selection transistor 84 is turned on.

  When the row selection transistor 84 is turned on, a pixel signal corresponding to the amount of accumulated charge is output from the amplification transistor 83 to the vertical signal line 86. The pixel signals output to the vertical signal line 86 are input to the CDS circuit 79, respectively.

  The timing generator 75 receives the accumulation signal output from the body drive control circuit 51 and outputs a reset signal to the reset circuit 76. In response to the end of the accumulation signal output from the body drive control circuit 51, the vertical synchronization signal is output to the vertical scanning circuit 77 and the horizontal synchronization signal is output to the horizontal scanning circuit 78.

Reset circuit 76 receives the reset signal output from the timing generator 75 sequentially outputs a control signal ΦR ₁ ~ΦR _n every predetermined time for each horizontal line. The predetermined time refers to the time for transferring the pixel signals of all the pixels arranged on the same horizontal line to the CDS circuit 79 in each column, and the pixel signal from which noise is removed by the CDS circuit 79 in each column to the ADC 80. Time for A / D conversion.

The vertical scanning circuit 77 receives the vertical synchronizing signal output from the timing generator 75 sequentially outputs a control signal ΦS ₁ ~ΦS _n in each horizontal line.

The horizontal scanning circuit 78 receives the horizontal synchronization signal output from the timing generator 76 and sequentially outputs the control signals ΦV _{1 to} ΦV _m .

The CDS circuit 79 performs correlated double sampling processing on the input pixel signal, and removes a noise component superimposed on the pixel signal. Thereafter, when the control signals ΦV _{1 to} ΦV _m are output from the horizontal scanning circuit 78, the pixel signal from which the noise component has been removed is sequentially transferred from each CDS circuit 79 to the ADC 80. The analog pixel signal sequentially transferred to the ADC 80 is converted into a digital pixel signal by the ADC 80 and is output as photometric data.

  As described above, when a CMOS image sensor is used as the photometric sensor 37, a rolling shutter that is a line exposure sequential readout method is used as the electronic shutter of the photometric sensor 37. This rolling shutter sequentially executes drive readout of each pixel in the photometric sensor 37, specifically, reset, exposure, pixel signal output, and next charge accumulation for each row (horizontal line).

  Next, drive control of the photometric sensor 37 will be described. The drive control of the photometric sensor 37 is executed using standby control. In this standby control, when the photometric sensor 37 is not driven and controlled, a standby signal is output from the body drive control circuit 51 to the photometric sensor 37. In response to the standby signal, power supply to the plurality of pixels P (i, j), the reset circuit 76, the vertical scanning circuit 77, the horizontal scanning circuit 78, and the like of the photometric sensor 37 is stopped. As a result, the photometric sensor 37 enters a standby state, and charge accumulation in a plurality of pixels is stopped. In this state, power is supplied to the timing generator 75, but signals to each circuit of the photometric sensor 37 are invalidated.

  On the other hand, when drive control of the photometric sensor 37 is performed, the output of the standby signal from the body drive control circuit 51 to the photometric sensor 37 is stopped. In response to the stop of the output of the standby signal, power supply to the plurality of pixels P (i, j), the vertical scanning circuit 77, the horizontal scanning circuit 78, the reset circuit 76, and the like of the photometric sensor 37 is started. As a result, the photometric sensor 37 is activated, and charges are accumulated in the plurality of pixels P (i, j). Note that after the output of the standby signal is stopped, a control signal for switching the driving mode is output.

  As shown in FIG. 5, the digital camera 10 repeatedly executes a photometry cycle in which the photometry operation of the object scene and the scene analysis operation are set to one cycle when not photographing. In the following, since the content of the photometry sensor 37 drive control in the object scene photometry operation and the scene analysis operation is the same, drive control of the photometry sensor 37 when performing the object photometry operation will be described below.

  As shown in FIG. 6, the body drive control circuit 51 stops outputting the standby signal to the photometric sensor 37 and outputs a control signal. As a result, the photometric sensor 37 is switched from the standby state to the activated state, and power supply to the plurality of pixels P (i, j), the vertical scanning circuit 77, the horizontal scanning circuit 78, the reset circuit 76, and the like of the photometric sensor 7 is started. The

After the photometric sensor 37 is switched to the operating state, the body drive control circuit 51 outputs an accumulation signal to the photometric sensor 37. In response to this accumulated signal, the timing generator 75 outputs a reset signal to the reset circuit 76. In response to this, the reset circuit 76 outputs the control signal ΦR ₁ to the pixels arranged in the first horizontal line. By outputting the control signal ΦR _1, the pixels arranged in the horizontal line of the first row are reset, and the charge accumulation of each pixel arranged in the horizontal line of the first row is performed at the falling edge of the control signal ΦR _1. Be started. Then, every time a predetermined time elapses, control signals ΦR ₂ , ΦR ₃ ,..., ΦR _n are sequentially output for the pixels arranged in the second and subsequent horizontal lines. That is, charge accumulation is sequentially started in each of the pixels arranged in each horizontal line. Here, the predetermined time is the time from when the pixel signals of all the pixels arranged on the same horizontal line are output from each pixel until the ADC 80 performs A / D conversion.

When the charge accumulation time elapses after the accumulated signal is output from the body drive control circuit 51 to the photometric sensor 37, the body drive control circuit 51 stops outputting the accumulated signal and outputs a read signal to the photometric sensor 37. The timing generator 75 outputs a vertical synchronization signal to the vertical scanning circuit 77. Then, the vertical scanning circuit 77 sequentially outputs a control signal ΦS ₁ ~ΦS _n.

The timing generator 75 outputs a horizontal synchronization signal to the horizontal scanning circuit 78 when outputting a vertical synchronization signal to the vertical scanning circuit 77. The horizontal scanning circuit 78 sequentially outputs control signals ΦV _{1 to} ΦV _m . Thereby, pixel signals are read out from the pixels arranged in each horizontal line for each line. The pixel signal to be read out is subjected to noise removal by a CDS circuit 79 provided in each column, then subjected to A / D conversion by ADC, and output as photometric data.

  When reading of the image signal from all of the plurality of pixels provided in the photometric sensor 37 is completed, the body drive control circuit 51 outputs a standby signal to the photometric sensor 37. Thereby, the power supply to the plurality of pixels and each circuit is stopped. That is, the photometric sensor 37 is switched from the operating state to the standby state. The photometric data output from the photometric sensor 37 is used for photometric calculation in the image processing circuit.

  When a predetermined time elapses from the above-mentioned photometry operation of the object scene, a scene analysis operation is executed. Here, the predetermined time is a time related to a photometric calculation using photometric data in the image processing circuit. The drive control of the photometric sensor 37 in this scene analysis operation is the same drive control as that of the photometric sensor 37 during the photometric operation of the object scene. That is, by stopping the standby signal from the body drive control circuit 51 to the photometric sensor 37 and outputting the control signal, the photometric sensor 37 is switched from the standby state to the operating state. Thereafter, the body drive control circuit 51 performs drive control of the photometric sensor 37 in the scene analysis operation. Also in this scene analysis operation, the body drive control circuit 51 outputs a standby signal to the photometric sensor 37 upon completion of reading of the pixel signal of each pixel. Thereby, after the scene analysis operation is executed, the photometric sensor 37 is switched from the operating state to the standby state.

  Since the standby signal is input to the photometric sensor 37 from the end of the scene analysis to the end of one photometric cycle, the photometric sensor 37 is held in a standby state. The second and subsequent photometric cycles are executed in the same cycle as the first photometric cycle.

  Here, when standby control is not performed on the photometric sensor 37, when drive control of the photometric sensor 37 is not executed, the photometric sensor 37 is controlled in the same manner as when drive control of the photometric sensor 37 is executed. Power is supplied to each part. In this state, charge accumulation is executed in a plurality of pixels of the photometric sensor 37, and power is wasted for this charge accumulation. Here, in one cycle of the photometry cycle, the more periods in which the photometry operation and scene analysis operation of the object scene are not performed, the more power is wasted.

  On the other hand, when performing standby control for the photometric sensor 37 of the present invention, when not performing drive control of the photometric sensor 37, the plurality of pixels P (i, j), the reset circuit 76, and the vertical scanning circuit 77 of the photometric sensor 37 are used. The power supply to the horizontal scanning circuit 78 and the like is stopped. That is, in a period in which the photometric sensor 37 is not driven and controlled in the photometric cycle, power supply to the pixels of the photometric sensor 37, the vertical scanning circuit 77, the horizontal scanning circuit 78, the reset circuit 76, and the like is stopped, and unnecessary power supply is performed. Since it is lost, power is not wasted.

  If the release button is pressed halfway in the process of repeatedly executing the above-mentioned photometry cycle, the photometry cycle is interrupted and the photometry operation of the object scene shown in FIG. 6 is executed. Then, the shooting conditions are determined using the photometric data obtained by the photometric operation of the object scene by the full press operation of the release button, and the body drive control circuit 51 is determined in response to the full press operation of the release button. An imaging process is executed based on the imaging conditions. Also in this case, the body drive control circuit 51 outputs a standby signal to the photometric sensor 37 after the photometric operation of the object scene is performed. As a result, the photometric sensor 37 is maintained in a standby state while the imaging process is being performed.

  In the digital camera 10, when flash photography is performed in the process of repeatedly performing the photometry operation and the scene analysis operation as one cycle, the photometry cycle is interrupted and the operation related to TTL light control is performed. Executed.

  As is well known, the processing related to TTL dimming is performed by measuring light data when preliminary light emission (monitor light emission) is first performed by the flash device 52 and photometric data when flash light emission is not performed by the flash device 52 (using steady light). Photometry data) is acquired by the photometry sensor 37, and the amount of flash light emitted from the flash device at the time of main light emission is adjusted based on the reflected light component obtained from the photometry data.

  Here, as shown in FIG. 7, the drive control of the photometric sensor 37 in the TTL light control is executed as follows. In this case as well, the start of the output of the standby signal from the body drive control circuit 51 to the photometric sensor 37 is stopped in the same manner as the photometric sensor 37 drive control in the scene photometry and scene analysis.

The body drive control circuit 51 stops outputting the standby signal to the photometric sensor 37 and outputs a control signal. Thereby, the photometric sensor 37 is switched from the standby state to the operating state. After the photometric sensor 37 is switched from the standby state to the operating state, the body drive control circuit 51 outputs an accumulation signal. In response to this accumulated signal, the timing generator 75 outputs a reset signal to the reset circuit 76. In response to this, the reset circuit 76 outputs the control signal ΦR ₁ to the pixels arranged in the first horizontal line. By outputting the control signal ΦR _1, the pixels arranged in the horizontal line of the first row are reset, and the charge accumulation of each pixel arranged in the horizontal line of the first row is performed at the falling edge of the control signal ΦR _1. Be started. Then, every time a predetermined time elapses, control signals ΦR ₂ , ΦR ₃ ,..., ΦR _n are sequentially output for the pixels arranged in the second and subsequent horizontal lines. That is, charge accumulation is sequentially started in each of the pixels arranged in each horizontal line.

After the accumulation of electric charge is started in each of the plurality of pixels, monitor light emission in the flash device 52 is executed. In response to the end of the monitor light emission, the body drive control circuit 51 stops outputting the accumulation signal and outputs a read signal to the photometric sensor 37. The timing generator 75 outputs a vertical synchronization signal to the vertical scanning circuit 77. Then, the vertical scanning circuit 77 sequentially outputs a control signal ΦS ₁ ~ΦS _n. The timing generator 75 outputs a horizontal synchronization signal to the horizontal scanning circuit 78 when outputting a vertical synchronization signal to the vertical scanning circuit 77. The horizontal scanning circuit 78 sequentially outputs control signals ΦV _{1 to} ΦV _m . Thereby, pixel signals are read out from the pixels arranged in each horizontal line for each line. The pixel signal to be read is subjected to noise removal by a CDS circuit 79 provided in each column, and then A / D conversion by ADC is performed and output to the image processing circuit 55. Thereby, photometric data when monitor light emission is performed is acquired.

  After acquiring the photometric data when the monitor light emission is performed, the body drive control circuit 51 performs photometry of the object scene in the steady light. In the metering of the object scene with the stationary light, the body drive control circuit 51 drives and controls the metering sensor 37 under the same conditions as those when the flash device 52 performs monitor light emission to measure the object field. Thereby, photometric data in the steady light is acquired. The photometric data in the stationary light is output to the image processing circuit 55. After performing the photometry of the object field in the stationary light, the body drive control circuit 51 outputs a standby signal to the photometry sensor 37. In response to this, the photometric sensor 37 is switched from the operating state to the standby state. That is, when the charge is continuously accumulated in the plurality of pixels P (i, j) such as TTL dimming, the body drive control circuit 51 does not output a standby signal to the photometric sensor 37. Since it is not necessary to switch the photometric sensor 37 between the standby state and the operating state, it is possible to reduce the time lag between the acquisition of the photometric data at the time of monitor light emission and the acquisition of the photometric data in the steady light.

  In the present embodiment, during TTL light control, a standby signal is not output from the body drive control circuit 51 to the photometry sensor 37 after the photometry operation of the object scene when monitor light emission is performed, and the object in normal light is captured. The photometric operation of the field has started. However, after the photometric operation of the object field when monitor light emission is performed, charges are accumulated in the pixels arranged in the read horizontal line. Since power is consumed by this charge accumulation, for example, a reset signal is output to the pixel from which the accumulated charge is read, and the next charge accumulation is executed in the pixel from which the charge has been read. It is also possible to control so that it does not occur.

  In the present embodiment, an example of a digital camera is taken up, but the present invention is not limited to this, and a photometric device including each unit shown in FIG. 2 may be used.

  In this embodiment, TTL dimming using a flash device provided in a digital camera is described. However, the present invention is not limited to this, and TTL dimming is performed using a flash device attached to and detached from the digital camera. Even in this case, the present invention can be applied.

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 37 ... Photometry sensor, 51 ... Body drive control circuit, 52 ... Flash apparatus, 55 ... Image processing circuit, 61 ... Sensor drive part, 66 ... Data processing part, 67 ... Control calculation part, 68 ... Photometry calculation 69: TTL light control unit 70: Subject discrimination unit 71 71 Subject tracking unit

Claims (10)

A light emission amount calculation unit that has a plurality of pixels and outputs a first output signal output from the plurality of pixels to the exposure calculation unit when calculating an exposure by an exposure calculation unit that calculates exposure, and calculates a light emission amount An imaging unit that outputs a second output signal output from the plurality of pixels to the light emission amount calculating unit when calculating a light emission amount by the output, and suppresses power supply to the plurality of pixels when a suppression signal is supplied; ,
  A first accumulation operation by the plurality of pixels for outputting the first output signal; and a second accumulation operation by the plurality of pixels for outputting the first output signal performed after the first accumulation operation. A third accumulation operation by the plurality of pixels for outputting the suppression signal to the imaging unit and outputting the second output signal between the accumulation operation and the third accumulation operation; An imaging apparatus comprising: a control unit that does not output the suppression signal to the imaging unit during a fourth accumulation operation by the plurality of pixels for outputting a second output signal. The imaging apparatus according to claim 1 ,
An exposure calculator for calculating the exposure;
A light emission amount calculation unit that calculates a light emission amount. An imaging apparatus according to claim 2,
The said exposure calculating part is an imaging device which has a photometry calculating part which calculates photometric light quantity based on the photometric result of an object scene. The imaging apparatus according to any one of claims 1 to 3, wherein
  The plurality of pixels is an imaging device that stops an accumulation operation when power supply is suppressed. The imaging apparatus according to any one of claims 1 to 4 , wherein
The third accumulating operation is an accumulating operation when metering monitor light emission emitted before the main light emission, and the fourth accumulating operation is an accumulating operation when metering steady light. Imaging device. An imaging apparatus according to any one of claims 1 to 5, wherein
  The imaging unit that outputs the control signal for switching the drive mode of the imaging unit after the control unit outputs the suppression signal and stops outputting the suppression signal. The imaging apparatus according to any one of claims 1 to 6, wherein
  A photometric sensor that is switched between an operating state for accumulating charge and a standby state for waiting for the charge accumulation;
  When the charge accumulation starts, the photometric sensor in the standby state is switched to the operating state, and after the accumulated charge is read, the photometric sensor in the active state is switched to the standby state. A sensor driving unit;
  An imaging apparatus comprising: The imaging apparatus according to claim 7, wherein
  The plurality of pixels are arranged two-dimensionally,
  The sensor driving unit drives the photometric sensor in the operating state by a rolling shutter that sequentially reads out charges accumulated in pixels arranged in the same line among the plurality of pixels of the photometric sensor for each line. An imaging device to be controlled.   An imaging unit that has a plurality of pixels and outputs an output signal output from the plurality of pixels to an exposure calculation unit that calculates exposure and a light emission amount calculation unit that calculates light emission amount;
  A first accumulation operation by the plurality of pixels for outputting the output signal to the exposure calculation unit, and the plurality for outputting the output signal to the exposure calculation unit performed after the first accumulation operation The third accumulation by the plurality of pixels for performing the control to suppress the power supply to the plurality of pixels during the second accumulation operation by the pixels and outputting the output signal to the light emission amount calculation unit The power supply to the plurality of pixels is performed between the operation and the fourth accumulation operation by the plurality of pixels for outputting the output signal to the light emission amount calculation unit performed after the third accumulation operation. An imaging apparatus having a control unit that does not perform control to suppress. An imaging apparatus according to claim 9, wherein
  The third accumulating operation is an accumulating operation when metering monitor light emission emitted before the main light emission, and the fourth accumulating operation is an accumulating operation when metering steady light. Imaging device.

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