JP2012147187A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus for shortening time until a next still image can be photographed.SOLUTION: The imaging apparatus includes: an imaging element in which a plurality of pixels generating a signal charge corresponding to an exposure amount are two-dimensionally arranged and which includes a memory storing image signals of the whole pixels; an imaging control section performing first reading control to make the imaging element perform first exposure, and to make the image signals of the whole exposed pixels to be stored in the memory so as to make them to be sequentially read at every field, and second reading control to make the imaging element perform second exposure, and to read the image signal on the second exposure from at least a part of the pixels included in the field where the first reading control is terminated during two field reading periods whose orders continue; and a photograph condition determining section for determining a photograph condition on next and subsequent first exposure control based on the image signal which is read by the second reading control.

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus that acquires an image signal by performing exposure.

  When shooting a still image, AE and AF operations are usually performed prior to exposure, and in the case of flash emission, a pre-emission operation is further performed to determine the amount of main emission. There is also.

  These AE and AF operations or flash pre-flash operation (including pre-flash preparation operation and main flash preparation operation) must be performed prior to exposure of a still image. Since a certain amount of execution time is required, the exposure of a still image is started after the time spent for execution.

  Here, in the exposure control related to the AE, an optical diaphragm (hereinafter simply referred to as a diaphragm) that defines the passage range of the photographing light beam is often used. Since it is configured to be mechanically controlled, it takes a certain amount of time to change its aperture diameter.

  In addition to the configuration in which the AF is provided with a dedicated distance measuring element, a configuration in which image data obtained from an imaging element that captures a still image is used is known. The latter is the so-called imager AF (IAF), which acquires the image signal of the AF target area multiple times while moving the focus lens, and determines the lens position where the contrast component of the obtained image is maximized. This is a technique for searching and setting the searched lens position as a focus position. Therefore, when the imager AF is used, a certain amount of time is required until focusing is achieved.

  Further, the pre-flash is performed during the pre-flash exposure in order to obtain data that determines the flash emission amount of the main flash, and is performed at least once (usually, the flash amount is reduced before the main flash is performed). A plurality of pre-flashes are performed while differently. Both the pre-light emission and the main light emission require a light emission preparation operation prior to actual light emission, and this light emission preparation operation requires a certain amount of time. As an example, FIG. 3 of Japanese Patent Application Laid-Open No. 2003-116142 describes a technique for performing strobe pre-flash exposure prior to the main exposure. This strobe pre-emission is performed during vertical synchronization prior to the main exposure, and it can be seen that when pre-emission described in the publication is performed, it takes a considerable time to start exposure of a still image.

JP 2003-116142 A

  Conventionally, after all the image signals obtained by one still image exposure are read out, the procedure for performing the AE, AF, and flash emission preparation operations is difficult. Therefore, it is difficult to reduce the release time lag, and the unit time It was also difficult to increase the number of consecutive shots per hit.

  The present invention has been made in view of the above circumstances, and can shorten the time until the next still image can be shot, and thus can be compared with a case where readout of a still image is performed without division. An object of the present invention is to provide an imaging apparatus capable of increasing the number of images that can be continuously shot per hour.

  In order to achieve the above object, an imaging apparatus according to an aspect of the present invention is an imaging apparatus that performs exposure to acquire an image signal, and a plurality of pixels that generate signal charges according to the exposure amount are two-dimensionally arranged. An image pickup device that is arranged and includes a memory that stores image signals of all pixels, a first exposure control that causes the image pickup device to perform a first exposure, and the image pickup device that has undergone the first exposure. First reading control for storing image signals of all pixels in the memory, sequentially reading the image signals of all pixels stored in the memory for each field, and causing the image sensor to perform second exposure. Between the exposure control of 2 and the two field readout periods in which the order in the first readout control is continuous, the second readout from at least a part of the pixels included in the field in which readout by the first readout control is completed Exposure A first readout control for the next time or later based on an image pickup control unit for performing a second readout control for reading out the image signal according to the control and an image signal read out by the second readout control. A photographing condition determining unit for determining the photographing condition according to the above.

  According to the imaging apparatus of the present invention, it is possible to shorten the time until the next still image can be captured, compared to the case where readout of a still image is not performed, and consequently continuous shooting per unit time. The number of possible sheets can be increased.

1 is a block diagram illustrating a configuration of an imaging apparatus according to Embodiment 1 of the present invention. FIG. 3 is a circuit diagram illustrating a configuration example of a pixel provided in the image sensor in the first embodiment. FIG. 3 is a diagram illustrating a state of potential and charge in a pixel during charge accumulation (exposure) in the first embodiment. FIG. 3 is a diagram illustrating a state of potential and charge in a pixel during global transfer in the first embodiment. FIG. 4 is a diagram illustrating the potential and charge state in a pixel when charge is held under a transistor TX2 after global transfer is completed in the first embodiment. FIG. 6 is a diagram illustrating the potential and charge state in a pixel when waiting for the charge under the transistor TX2 to be transferred in the first embodiment. FIG. 6 is a diagram illustrating the potential and charge state in a pixel when charge is transferred from the bottom of a transistor TX2 to the signal storage unit FD in the first embodiment. FIG. 3 is a diagram illustrating a state of potential and charge in a pixel when charge is held in a signal accumulation unit FD in the first embodiment. In the said Embodiment 1, the timing chart which shows operation | movement of the imaging device at the time of live view. 4 is a timing chart illustrating the operation of the imaging apparatus when performing live view display while continuously shooting and reading out a plurality of still images in Embodiment 1. FIG. 4 is a timing chart showing processing for performing AE based on an image signal obtained from an imaging element during divided readout of a still image in the imaging apparatus of the first embodiment. 6 is a flowchart illustrating processing for performing AE based on an image signal obtained from an image sensor during divided reading of a still image in the imaging apparatus according to the first embodiment. 9 is a timing chart showing processing for performing AF based on an image signal obtained from an image sensor during divided readout of a still image in the imaging apparatus according to the second embodiment of the present invention. 7 is a flowchart illustrating processing for performing imager AF based on an image signal obtained from an image sensor during divided reading of a still image in the imaging apparatus according to the second embodiment. 9 is a timing chart illustrating processing for determining the flash emission amount of main light emission based on an image signal obtained by performing pre-light emission while a still image is being divided and read out in the imaging apparatus according to the third embodiment of the present invention. 7 is a flowchart illustrating processing for determining the flash emission amount of main light emission based on an image signal obtained by performing pre-light emission while a still image is being divided and read out in the imaging apparatus according to the third embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[Embodiment 1]

  1 to 12 show Embodiment 1 of the present invention, and FIG. 1 is a block diagram showing a configuration of an imaging apparatus.

  As shown in FIG. 1, the imaging apparatus includes a lens 1 and a lens control unit 2 that are lens units, an aperture 3 and an aperture control unit 4 that are aperture units, an imaging element 5 and an imaging control unit 6 that are imaging units. An A / D conversion unit 7, a volatile memory 8, an image processing unit 9, an exposure control unit 10, an AF processing unit 11, a display unit 13, an operation unit 14, a nonvolatile memory 15, A flash control unit 16, a flash charging unit 17, a flash light emitting unit 18, a power source control unit 19, a power source unit 20, and a system control unit 21, which are flash units, are provided. Although the external memory 12 is also illustrated in FIG. 1, the external memory 12 is configured as a memory card that can be attached to and detached from the imaging apparatus, and thus may not have a configuration unique to the imaging apparatus. I do not care.

  The lens 1 forms an optical image of a subject in the imaging area of the imaging device 5 and includes a focus lens for adjusting the focus position.

  The lens control unit 2 drives the focus lens of the lens 1 in order to adjust the focus position. That is, the lens control unit 2 drives the focus lens included in the lens 1 based on the control of the system control unit 21 that has received the AF evaluation value related to the imager AF (IAF) from the AF processing unit 11, and the imaging element 5. The subject image formed on the lens is brought into focus. The lens control unit 2 outputs lens drive information such as a lens position to the system control unit 21.

  The stop 3 mechanically controls the passage range of the light beam reaching the image sensor 5 from the lens 1. As described above, since the diaphragm 3 is mechanically controlled, as described later, it takes a certain amount of time to change the diaphragm value.

  The aperture control unit 4 controls and drives the aperture 3 so as to obtain the aperture value based on the control of the system control unit 21 that has received the aperture value determined by the exposure control unit 10. The aperture control unit 4 is configured to output aperture drive information to the system control unit 21.

  The imaging element 5 is an imaging sensor that photoelectrically converts an optical image of a subject imaged by the lens 1 and outputs it as an image signal. This imaging device 5 has an imaging region in which a plurality of pixels that generate signal charges according to the exposure amount are two-dimensionally arranged, and includes a memory that stores image signals of all pixels, and includes one frame. Divided reading can be performed by dividing into a plurality of fields. Further, the image sensor 5 reads out only a desired partial area in the imaging area (for example, readout of a distance measurement area for AF, readout of a photometry area for AE, readout of a dimming area for flash light control, etc.) Is possible. A specific pixel configuration example of the image sensor 5 will be described later with reference to FIG.

  The imaging control unit 6 starts exposure by resetting a photoelectric conversion unit PD (see FIG. 2) in the pixels of the image sensor 5, ends exposure by transferring signal charges accumulated in the photoelectric conversion unit PD, and from the photoelectric conversion unit PD. The image pickup operation related to the image pickup device 5 such as reading of the charge transferred to the memory (see FIG. 2) in the pixel is controlled. The control of the imaging control unit 6 includes control of a so-called global shutter (an element shutter that is an exposure start by all pixel collective reset and an exposure end by collective transfer of signal charges of all pixels). As will be described in detail later, the imaging control unit 6 performs first exposure control for causing the imaging device 5 to perform first exposure (specifically, main exposure using a global shutter), and the first exposure. The image signal of all the pixels of the image pickup device 5 subjected to the above is stored in the memory, and the image signal of all the pixels stored in the memory is sequentially read for each field, and the image pickup device 5 has the second read control. Between the second exposure control for performing the exposure (specifically, the exposure for moving images by the global shutter and the exposure for determining the shooting conditions) and two field readout periods in which the order in the first readout control is continuous. In addition, second readout control for reading out an image signal related to the second exposure control from at least a part of the pixels included in the field in which readout by the first readout control is completed is performed.

  The A / D conversion unit 7 amplifies the analog image signal output from the image sensor 5 in accordance with the sensitivity setting, and converts it into a digital signal.

  The volatile memory 8 is for temporarily storing the image signal converted into digital by the A / D converter 7.

  The image processing unit 9 performs various image processing on the image signal stored in the volatile memory 8 based on the control of the system control unit 21. The image processing unit 9 reads the image signal read out by the above-described second reading control stored in the volatile memory 8 (or, if necessary, read out by the above-described first reading control). It also has a function of extracting photometric data and AF data from the image signal and outputting them to the system control unit 21.

  The exposure control unit 10 is based on photometric data received from the image processing unit 9 via the system control unit 21, and exposure values such as shutter speed (exposure time), aperture value, and shooting sensitivity (gain) as shooting conditions. Is an imaging condition determination unit for determining. Accordingly, the exposure control unit 10 functions as an exposure condition determining unit that determines an exposure condition including the aperture value of the aperture unit as a shooting condition related to the first exposure control for the next time or thereafter based on the photometric data. The aperture controller 4 described above receives the aperture value determined by the exposure controller 10 via the system controller 21 and controls and drives the aperture 3. Similarly, the imaging control unit 6 described above receives the exposure time determined by the exposure control unit 10 via the system control unit 21 and controls the element shutter of the imaging device 5.

  The AF processing unit 11 is an imaging condition determination unit that calculates an AF evaluation value as an imaging condition based on the AF data received from the image processing unit 9 via the system control unit 21 and outputs the AF evaluation value to the system control unit 21. is there. As described above, the imaging apparatus is configured to perform autofocus by the imager AF. The system control unit 21 also functions as an imaging condition determination unit that calculates a lens driving amount as an imaging condition based on the AF evaluation value received from the AF processing unit 11 and outputs the lens driving amount to the lens control unit 2. The lens control unit 2 described above receives the lens driving amount calculated by the system control unit 21 and drives the focus lens included in the lens 1.

  The external memory 12 is a non-volatile recording medium for storing a signal image-processed for recording by the image processing unit 9.

  The display unit 13 displays an image based on a signal image-processed for display by the image processing unit 9. The display unit 13 performs live view (LV) display and still image display, and also displays various information related to the imaging apparatus.

  The operation unit 14 is for performing various operation inputs to the imaging apparatus. The operation unit 14 includes a power switch for turning on / off the power of the imaging apparatus, a release button for inputting instructions for single image shooting, continuous shooting, and moving image shooting, a still image shooting mode and a moving image shooting mode. Mode for setting continuous shooting mode, flash firing mode, AF mode (continuous AF, single AF, etc.), AE mode (program AE, aperture priority AE, shutter speed priority AE, etc.), live view mode, etc. Operation members such as buttons are included.

  The non-volatile memory 15 is a memory for storing in a non-volatile manner a processing program for controlling the entire imaging apparatus executed by the system control unit 21 and parameters used for various processes.

  The flash unit irradiates the subject with illumination light under the control of the system control unit 21, and includes the flash control unit 16, the flash charging unit 17, and the flash light emitting unit 18 as described above.

  The flash control unit 16 controls the charging operation of the flash charging unit 17, the light emission amount of the flash light emitting unit 18, the light emission timing, and the like.

  The flash charging unit 17 accumulates energy supplied from the power supply control unit 19 and supplies it to the flash light emitting unit 18 as energy for causing the flash light emitting unit 18 to emit light.

  The flash light emitting unit 18 emits flash using the energy supplied from the flash charging unit 17 based on the trigger signal input from the flash control unit 16.

  The power supply control unit 19 supplies power supplied from the power supply unit 20 to each unit in the imaging apparatus including the system control unit 21.

  The power supply unit 20 is a power supply source configured to include a secondary battery or a primary battery.

  The system control unit 21 is based on the lens drive information from the lens control unit 2, the exposure time and aperture value from the exposure control unit 10, the AF evaluation value from the AF processing unit 11, the operation input from the operation unit 14, and the like. Lens control unit 2, aperture control unit 4, imaging control unit 6, volatile memory 8, image processing unit 9, exposure control unit 10, AF processing unit 11, external memory 12, display unit 13, operation unit 14, non-volatile memory 15, the entire image pickup apparatus including the flash control unit 16, the power supply control unit 19 and the like is controlled.

  Next, FIG. 2 is a circuit diagram illustrating a configuration example of pixels provided in the image sensor 5.

  In FIG. 2, PD (photodiode) is a photoelectric conversion unit, and FD (floating diffusion) is a signal storage unit that temporarily holds a signal of the photoelectric conversion unit PD at the time of charge reading.

  FT is a transistor that resets the photoelectric conversion unit PD when a PD reset pulse is applied, and is connected to the photoelectric conversion unit PD and the voltage source VDD.

  Three transistors TX1, TX2, TX3 are connected in series between the photoelectric conversion unit PD and the signal storage unit FD, and by applying a control signal to the transistors TX1 and TX3 to form a potential barrier, The semiconductor portion below the transistor TX2 can function as a memory. Therefore, the transistor TX1 functions as a gate unit that transfers the signal of the photoelectric conversion unit PD to the lower side of the transistor TX2, and the transistor TX3 functions as a gate unit that transfers the signal of the lower side of the transistor TX2 to the signal storage unit FD. In addition, the three transistors TX1, TX2, and TX3 function as a transfer unit and a gate unit that transfer the signal of the photoelectric conversion unit PD to the signal storage unit FD as a whole.

  Ta is an amplifying transistor that functions as an amplifying unit, and a voltage source VDD and a current source constitute a source follower amplifier. The signal of the signal storage unit FD is amplified by the amplifying transistor Ta and is output to the vertical transfer line through the selection transistor Tb to which the selection pulse is applied.

  Tc is a transistor for resetting the input part of the signal storage part FD and the amplifying transistor Ta, and an FD reset pulse is applied thereto.

  Next, charge transfer in the pixel will be described with reference to FIGS. 3 is a diagram showing the potential and charge in the pixel during charge accumulation (exposure), FIG. 4 is a diagram showing the potential and charge in the pixel during global transfer, and FIG. 5 is the completion of global transfer. FIG. 6 is a diagram illustrating the potential and charge state in the pixel when the charge is held below the transistor TX2, and FIG. 6 illustrates the potential and charge in the pixel when waiting for the charge under the transistor TX2 to be transferred. FIG. 7 is a diagram showing the state of charge, FIG. 7 is a diagram showing the state of the potential in the pixel and the charge when the charge is transferred from the bottom of the transistor TX2 to the signal storage unit FD, and FIG. It is a figure which shows the mode of the potential and electric charge in a pixel when carrying out. Note that since charges generated by photoelectric conversion are electrons, in these drawings, a higher potential is a lower potential and a lower potential is a higher potential.

  Before starting charge accumulation, the photoelectric conversion unit PD is reset by applying a reset pulse to the transistor FT. At the time of the global shutter, the reset of the photoelectric conversion unit PD is simultaneously performed for all the pixels in the image sensor 5. The time when the reset of the photoelectric conversion unit PD is completed is the time when the exposure is started.

  When light is applied to the photoelectric conversion unit PD, electrons that become charges are generated by the photoelectric effect. As shown in FIG. 3, the generated charges are accumulated in the photoelectric conversion unit PD having a lower potential than the transistors FT and TX1.

  When a predetermined exposure time has elapsed, the electric charge in the photoelectric conversion unit PD is transferred to the transistor TX2 as shown in FIG. 4 by making the potentials of the transistors TX1 and TX2 lower than the potential of the photoelectric conversion unit PD. The exposure is completed by this charge transfer. At the time of the global shutter, the charge transfer from the photoelectric conversion unit PD is simultaneously performed for all the pixels in the image sensor 5 (global transfer).

  After the transfer of charge from the photoelectric conversion unit PD is completed, control is performed so that the potential of the transistor TX1 becomes high again. As a result, as shown in FIG. 5, the electric charge is accumulated under the transistor TX2 functioning as a memory, and the subsequent reading is awaited.

  When reading is performed, control is first performed so that the potential of the transistor TX2 is higher than that of the signal storage unit FD, as shown in FIG.

  Then, after applying the FD reset pulse to the transistor Tc to reset the signal storage unit FD, the selection pulse is applied to the selection transistor Tb to read the reset voltage of the signal storage unit FD.

  Thereafter, by controlling the potential of the transistor TX3 so that the charge moves from the potential well of the transistor TX2 to the potential well of the signal storage unit FD, as shown in FIG. 7, the charge is transferred from below the transistor TX2 to the signal storage unit FD. Forward to.

  When the charge is transferred, control is performed so that the potential of the transistor TX3 becomes high again, and the charge is held in the signal storage unit FD as shown in FIG. Then, a selection pulse is applied to the selection transistor Tb to read out the signal voltage accumulated in the signal accumulation unit FD. The signal voltage read here is corrected from the previously read reset voltage and output from the image sensor 5.

  In this way, the image sensor 5 having the pixel configuration shown in FIG. 2 outputs an image signal in which reset noise is corrected.

  FIG. 9 is a timing chart illustrating the operation of the imaging apparatus during live view.

  The operation of the imaging unit including the imaging element 5 is performed based on the vertical synchronization signal VD generated from the imaging control unit 6.

  In the example shown in FIG. 9, the vertical synchronizing signal VD is generated alternately with a short-cycle signal for moving images and a long-cycle signal for still images.

  Here, the reason why the cycle of the vertical synchronizing signal VD for moving images is shorter than the cycle of the vertical synchronizing signal VD for still images is as follows. That is, the number of display pixels provided in the display unit 13 is generally smaller than the number of all pixels provided in the image sensor 5 (for example, the former has 10 million pixels). In contrast, the latter is 300,000 pixels). Accordingly, for example, a moving image signal is read out by thinning out at a ratio of one line to a plurality of lines, and pixel addition is performed in one line, so that the time required for reading is only a fraction of that of a still image. It is.

  The cycle of the short cycle vertical synchronization signal VD and the long cycle vertical synchronization signal VD is configured to be the same as the moving image display cycle. As shown in FIG. 9, the moving image capturing operation (operation by the second exposure control) is performed by performing a global reset indicated by a vertical dotted line and performing a global transfer indicated by a vertical line after a moving image exposure time has elapsed. It is executed by. After that, in synchronization with the short-cycle vertical synchronization signal VD, the video line signal is read out sequentially, for example, in units of lines (indicated by diagonal lines in FIG. 9). Accordingly, the moving image is output from the image sensor 5 in synchronization with the display cycle.

  In the example shown in FIG. 9, the moving image is read out, for example, for a part or all of even lines (2N lines: N is a positive integer).

  The moving image signal read from the image sensor 5 is stored in the volatile memory 8 via the A / D conversion unit 7, processed for moving image display by the image processing unit 9, and then displayed on the display unit 13 as a live view. Displayed as an image.

  Next, FIG. 10 is a timing chart showing the operation of the image pickup apparatus when performing live view display while continuously shooting and reading a plurality of still images.

  The operations in this case are the operations shown in FIG. 9 plus the operations of still image exposure, still image reading, and still image processing.

  That is, in the still image capturing operation (operation by the first exposure control), as shown in FIG. 10, global reset indicated by a thick vertical dotted line is performed, and global transfer indicated by a thick vertical line is performed after a still image exposure time has elapsed. It is executed by doing. After that, in synchronization with the long-cycle vertical synchronization signal VD, signals of all lines for still images are sequentially read, for example, in units of lines (indicated by diagonally thick lines in FIG. 10).

  However, since it is not possible to read out all the lines for a still image within one long-cycle vertical synchronization period, reading of a still image is performed by dividing it into a plurality of long-cycle vertical synchronization periods (divided reading). In the example shown in FIG. 10, the data is divided into even lines (2N lines) and odd lines (2N + 1 lines), and reading is performed every long vertical synchronization period. Further, as the moving image line, a part or all of the lines on which the first divided reading is performed (in the example shown in FIGS. 9 and 10, even lines as described above) are used.

  Note that for both still images and moving images, since the image signal is read out in synchronization with the vertical synchronization signal VD, the exposure period is performed in a vertical synchronization period that is earlier in time than that. . Accordingly, it may occur that the reading of still images and the exposure of moving images overlap in a period, or the reading of moving images and the exposure of a still image overlap in a period, for example as shown in FIG. Since the imaging device 5 having such a configuration is used, such duplication can be realized relatively easily.

  The still image signal read from the image sensor 5 is stored in the volatile memory 8 via the A / D conversion unit 7, processed for a still image by the image processing unit 9, and then stored in the external memory 12, for example. Is done.

  The live view image is continuously displayed on the display unit 13 while the still image is being read.

  Next, FIG. 11 is a timing chart showing a process of performing AE based on an image signal obtained from the image sensor 5 while a still image is being divided and read out in the imaging apparatus.

  In the processing of FIG. 10 described above, the live view image is exposed and read between the still images divided and read. In the processing of FIG. 11, instead of exposing and reading the live view image, the photometry image is read. Exposure and readout are performed.

  That is, as shown in FIG. 11, the photometric image capturing operation (operation by the second exposure control) performs a global reset indicated by the vertical dotted line and performs a global transfer indicated by the vertical line after the photometric exposure time has elapsed. Is executed. After that, in synchronism with the short-cycle vertical synchronization signal VD, for example, the readout of the photometry line signal is sequentially performed in units of lines as indicated by the oblique lines. Here, a part or all of the lines (for example, even lines as described above) on which the first divided readout is performed are used as the photometric lines, similarly to the moving image lines described above.

  The photometric image signal read from the image sensor 5 is stored in the volatile memory 8 via the A / D conversion unit 7, and the component corresponding to the luminance signal is extracted by the image processing unit 9, and the photometric data is obtained. Generated. The photometric data is input to the exposure control unit 10 via the system control unit 21. After the photometric calculation is performed and the photometric value is calculated, the next or subsequent still image is taken based on the photometric value. Exposure values such as shutter speed (exposure time), aperture value, and shooting sensitivity (gain), which are shooting conditions (shooting conditions related to first exposure control), are determined.

The period (aperture drive time) during which the aperture control unit 4 drives the aperture 3 related to the exposure control (first exposure control) of the still image at or after the next time so that the aperture value determined in this way is obtained. As shown in FIG. 11, at least a part of the reading control period (first reading control period) of a still image that requires a certain length of time and is currently being divided and read is overlapped.
Accordingly, in the present embodiment, the exposure control unit 10 functions as an exposure condition determining unit of the photographing condition determining unit.

  However, since the next still image cannot be captured unless the driving of the aperture stop 3 is completed, the period (accumulation time control range) from the time when the aperture drive ends to the time when the still image is globally transferred is within the range of the still image. This is a period that can be used for charge accumulation. Therefore, the global reset for the still image is performed within this accumulation time control range.

  The flow of such processing will be described with reference to FIG. FIG. 12 is a flowchart showing a process for performing AE based on the image signal obtained from the image sensor 5 while the still image is being divided and read out in the imaging apparatus.

  When this process is started, the operation waits for the release button of the operation unit 14 to be pressed to input a shooting instruction (step S1).

  Thus, when the system control unit 21 determines that the release button has been pressed, the image pickup control unit 6 controls the image pickup device 5 so as to perform exposure for photometry based on a command from the system control unit 21 (Step S1). S2).

  When the exposure is completed, a photometric image is read from the image sensor 5 (step S3).

  From the read photometric image, photometric data is extracted by the image processing unit 9, and the exposure control unit 10 determines the exposure conditions for still image shooting based on the extracted photometric data (step S4).

  The system control unit 21 determines whether or not the aperture value in the exposure condition determined by the exposure control unit 10 has been changed from the currently set aperture value (step S5).

  If it is determined that the aperture value has been changed, the system control unit 21 drives and controls the aperture 3 so that the aperture value designated via the aperture control unit 4 is obtained (step S6).

  If the process of step S6 ends or if it is determined in step S5 that the aperture value has not been changed, still image exposure is performed by global reset and global transfer (step S7).

  Then, a gain (still image sensitivity) necessary for amplifying the image signal read from the image sensor 5 after the still image exposure in step S7 is set (step S8).

  Next, the system control unit 21 determines whether or not the continuous shooting mode is set and the release button of the operation unit 14 is kept pressed (whether or not there is a continuous shooting instruction) (step S1). S9).

  If it is determined that there is a continuous shooting instruction, the first still reading of the still image exposed in step S7 or step S15 described later is performed and the photometric image is exposed (step S10). .

  When the first divided readout in the long-cycle vertical synchronization period is completed, the photometric image exposed in step S10 is read out in the subsequent short-cycle vertical synchronization period (step S11).

  Then, the exposure control unit 10 calculates a photometric value based on the photometric data extracted from the read photometric image, and the exposure control unit 10 uses the calculated photometric value to, for example, a still image based on the APEX system. The photographing exposure condition is determined (step S12).

  Subsequently, the system control unit 21 determines whether or not the aperture value in the exposure condition determined by the exposure control unit 10 in step S12 is changed from the currently set aperture value ( Step S13).

  If it is determined that the aperture value has been changed, the system control unit 21 drives and controls the aperture 3 so that the aperture value designated via the aperture control unit 4 is obtained (step S14). As described above, the driving of the diaphragm 3 is performed so that the period overlaps with the second divided reading of the still image that is subsequently performed.

  When the processing of step S14 is completed or when it is determined in step S13 that the aperture value has not been changed, the still image exposed in step S7 or the exposure performed when this step S15 was executed last time. The second divided readout of the still image is performed and the next still image exposure is performed (step S15).

  Then, the gain (still image sensitivity) when reading the still image newly exposed in step S15 is set to the gain in the exposure condition determined in step S12 (step S16), and then the process proceeds to step S9. Return.

  On the other hand, if it is determined in step S9 that there is no continuous shooting instruction, that is, if the release button is stopped during continuous shooting and the continuous shooting instruction ends, or the continuous shooting mode is not set. If only a single image is taken, if there is an unread image signal, the image signal is read (step S17). Note that the readout of the still image in step S17 does not necessarily have to be division readout. In this way, when the image signal is read out, this process is terminated.

According to the first embodiment, exposure for photometry can be performed while still images are divided and read, and the exposure control conditions for the next or subsequent still images can be determined. At this time, since the drive control period of the diaphragm 3 for capturing the next or subsequent still image can be overlapped with the still image divided readout period, the still image can be read out once without division. Compared with the case where the exposure for photometry is performed after this, the time until the next still image can be taken can be shortened. As a result, it is possible to increase the number of images that can be continuously shot per unit time.
[Embodiment 2]

  FIGS. 13 and 14 show the second embodiment of the present invention. FIG. 13 shows a process for performing AF based on an image signal obtained from the image sensor 5 while a still image is being divided and read out in the imaging apparatus. It is a timing chart which shows.

  In the second embodiment, parts that are the same as those in the first embodiment are given the same reference numerals and description thereof is omitted, and only differences are mainly described.

  In the processing of FIG. 11 of the first embodiment described above, the exposure and readout of the photometric image are performed between the still images being divided and read. In the processing of FIG. The exposure and readout are performed. In the present embodiment, an example is shown in which still images are divided and read out four times.

  That is, in the imager AF image capturing operation (operation by the second exposure control), as shown in FIG. 11, global reset indicated by the vertical dotted line is performed, and global transfer indicated by the vertical line is performed after the imager AF exposure time has elapsed. It is executed by doing. After that, in synchronization with the short-cycle vertical synchronization signal VD, the readout of the signal of the imager AF line is sequentially performed, for example, in units of lines as indicated by the oblique lines. Here, as the imager AF line, a part or all of the lines on which the first divided reading is performed are used, like the moving image line and the photometric line.

  In addition, in accordance with other embodiments, here, the imager AF line is part or all of the line on which the first divided reading is performed as shown in FIG. However, the present invention is not limited to this. The exposure for the imager AF can be started if the still image has already been transferred to the memory, and the still image has already been read out. If it is a pixel, readout for the imager AF can be performed. Therefore, the imager AF immediately after the first divided reading becomes a line or a part of the line read by the first divided reading, but the imager AF immediately after the second divided reading is read by the first or second divided reading. Similarly, the imager AF immediately after the third divided reading may be the line read by the first to third divided readings or a part thereof, and so on.

  The image signal for the imager AF read from the image sensor 5 is stored in the volatile memory 8 via the A / D conversion unit 7, and a component corresponding to the edge component is extracted by the image processing unit 9 to be used for the imager AF. Data is generated. The imager AF data is input to the AF processing unit 11 via the system control unit 21. The imager AF image signal that is the basis of such imager AF data is obtained by moving the focus position of the lens unit after the exposure control (first exposure control) for the still image is completed (this focus position). This movement is the same as in general imager AF, and is performed so as to search for the peak value of the edge amount), and is read out a plurality of times. The AF processing unit 11 calculates an AF evaluation value based on the imager AF data input multiple times as described above (imager AF calculation). The system control unit 21 receives the AF evaluation value from the AF processing unit 11 and becomes the in-focus position as a shooting condition (shooting condition related to the first exposure control) for shooting the next or subsequent still image. Determine the focus position of the lens unit.

  At this time, the period during which the lens control unit 2 drives the focus lens to determine the focus position at the next or subsequent still image shooting requires a certain amount of time as shown in FIG. In addition, at least a portion overlaps with the reading control period (first reading control period) of the still image currently being divided and read. However, although not shown as an example in FIG. 13, the focus lens is adjusted so that the focus position in the next or subsequent still image exposure control (first exposure control) becomes the focus position determined as described above. The driving period (the period in which the focus lens is driven to the focus position as indicated by an arrow in FIG. 13) is at least one time than the still image reading control period (first reading control period) currently being divided and read. You may make it overlap.

  Therefore, in the present embodiment, the AF processing unit 11 and the system control unit 21 function as a focus condition determining unit of the photographing condition determining unit.

  The flow of such processing will be described with reference to FIG. FIG. 14 is a flowchart showing a process of performing imager AF based on an image signal obtained from the image sensor 5 while a still image is being divided and read out in the imaging apparatus.

  When this process is started, the process waits for the release button of the operation unit 14 to be pressed to input a shooting instruction (step S21).

  Thus, if the system control unit 21 determines that the release button has been pressed, the lens control unit 2 drives the focus lens of the lens 1 based on the command from the system control unit 21 (step S22).

  Next, the imaging control unit 6 controls the imaging element 5 so as to perform exposure for the imager AF (step S23).

  When the exposure is completed, the imager AF image is read from the image sensor 5 (step S24).

  The imager AF data is extracted from the read imager AF image by the image processing unit 9, and the imager AF calculation is performed by the AF processing unit 11 based on the extracted imager AF data (step S25).

  The system control unit 21 determines whether or not an in-focus position (focus position) has been detected based on the result calculated by the AF processing unit 11 (step S26).

  If the in-focus position is not detected here, the process returns to the above-described step S22 to further search for the in-focus position while driving the focus lens.

  Thus, if it is determined in step S26 that the in-focus position has been detected, the system control unit 21 drives the focus lens of the lens 1 via the lens control unit 2 so that the detected in-focus position is obtained. Control (step S27).

  Thereafter, the still image is exposed by global reset and global transfer (step S28).

  Then, a gain (still image sensitivity) necessary for amplifying the image signal read from the image sensor 5 after the still image exposure in step S28 is set (step S29).

  Next, the system control unit 21 determines whether or not the continuous shooting mode is set and the release button of the operation unit 14 is kept pressed (whether or not there is a continuous shooting instruction) (step S1). S30).

  If it is determined that there is a continuous shooting instruction, the lens control unit 2 drives the focus lens of the lens 1 based on a command from the system control unit 21 (step S31).

  Next, the system control unit 21 determines whether or not the divided reading of the still image has been completed (step S32).

  In this step S32, when it is determined that the still image division reading has not been completed, the still image exposed in step S28 or step S40 or step S41 described later is divided and the imager AF image is read. Is exposed (step S33).

  On the other hand, if it is determined in step S32 that the still image division readout has been completed, only the imager AF image is exposed (step S34).

  When the exposure is completed in step S33 or step S34, the imager AF image is read in the subsequent vertical synchronization period (step S35).

  Then, based on the imager AF data extracted from the imager AF image read in step S35, the imager AF calculation is performed by the AF processing unit 11 (step S36).

  The system control unit 21 determines whether or not an in-focus position (focus position) has been detected based on the result calculated by the AF processing unit 11 (step S37).

  If the in-focus position is not detected here, the process returns to the above-described step S31 to search for the in-focus position while driving the focus lens.

  Thus, if it is determined in step S37 that the in-focus position has been detected, the system control unit 21 drives the focus lens of the lens 1 via the lens control unit 2 so that the detected in-focus position is obtained. Control is performed (step S38).

  Further, the system control unit determines whether or not the divided reading of the still image is completed (step S39).

  Here, if it is determined that the still image division reading has not been completed, the remaining division reading is performed, and the still image is exposed at the focus position driven by the lens in step S38 (step S40). .

  If it is determined in step S39 that the divisional reading of the still image has been completed, the still image is exposed at the focus position driven by the lens in step S38 (step S41).

  Then, a gain (still image sensitivity) for reading a still image newly exposed in step S40 or step S41 is set (step S42), and then the process returns to step S30.

  On the other hand, if it is determined in step S30 that there is no continuous shooting instruction, if there is an image signal that has not been read, the image signal is read (step S43). Note that the readout of the still image in step S43 is not necessarily limited to the division readout. In this way, when the image signal is read out, this process is terminated.

According to the second embodiment, IAF exposure can be performed while still images are being divided and read, and focus control for exposing the next or subsequent still images can be performed. At this time, the period during which the lens control unit 2 drives the focus lens to determine the in-focus position at the next or subsequent still image shooting can overlap the still image divided readout period. Compared with the case where the exposure for IAF is performed after the image is read once without division, the time until the next still image can be taken can be shortened. As a result, it is possible to increase the number of images that can be continuously shot per unit time.
[Embodiment 3]

  15 and 16 show Embodiment 3 of the present invention. FIG. 15 is based on an image signal obtained from the image sensor 5 by performing pre-emission while still images are being divided and read out in the imaging apparatus. It is a timing chart which shows the process which determines the flash emission amount of this light emission.

  In the third embodiment, parts that are the same as those in the first and second embodiments are given the same reference numerals, description thereof is omitted, and only differences are mainly described.

  In the process of FIG. 11 of the first embodiment described above, the photometric image is exposed and read in between the still image divided reading. In the process of FIG. 13 of the second embodiment described above, the still image is divided and read. In the meantime, the imager AF image is exposed and read out, but in the process of FIG. 15, instead of these, the preflash image is exposed and read out to determine the flash emission amount of the main flash. It has become. Note that the present embodiment is an example in which divided reading of a still image is performed in two steps.

  That is, in the pre-flash image capturing operation (operation by the second exposure control), as shown in FIG. 11, a global reset indicated by a vertical dotted line is performed, pre-flash is performed during the second exposure control period, This is executed by performing global transfer indicated by a vertical line after the light adjustment exposure time has elapsed since the global reset. After that, in synchronization with the short-cycle vertical synchronization signal VD, readout of the pre-emission line signal is sequentially performed, for example, in units of lines as indicated by diagonal lines. Here, as the pre-light emission line, a part or all of the lines on which the first division reading is performed are used, like the moving image line, the photometry line, and the imager AF line.

  The pre-emission image signal read from the image sensor 5 is stored in the volatile memory 8 via the A / D conversion unit 7, and the component corresponding to the luminance signal is extracted by the image processing unit 9, and the photometric data Is generated. The photometric data is input to the exposure control unit 10 via the system control unit 21 and photometric calculation is performed to calculate a photometric value. The system control unit 21 receives the calculated photometric value from the exposure control unit 10 and performs the main light emission as a shooting condition (shooting condition related to the first exposure control) for shooting a still image for the next time or after. The flash emission amount is determined, and the flash control unit 16 is controlled. The flash control unit 16 controls the flash charging unit 17 and the flash light emitting unit 18 to perform main light emission in accordance with the still image exposure timing (that is, during the first exposure control period).

  Therefore, in the present embodiment, the system control unit 21 functions as a flash emission amount determining unit of the photographing condition determining unit.

  At this time, if pre-emission is performed once between two consecutive still image exposure controls (first exposure control), preparation for emission of main emission is performed as shown in FIG. The period (which requires a certain amount of time as shown) overlaps at least partially with the first read control period. Further, when the pre-light emission is performed twice or more, although not shown, a period for preparing the light emission for the second or subsequent pre-light emission or the main light emission (also requires a certain amount of time). Is at least partially overlapping with the first read control period.

  The flow of such processing will be described with reference to FIG. FIG. 16 is a flowchart showing a process for determining the flash emission amount of the main light emission based on the image signal obtained from the image pickup device 5 by performing pre-light emission while the still image is being divided and read out in the image pickup apparatus. .

  When this process is started, the process waits for the release button of the operation unit 14 to be pressed to input a shooting instruction (step S51).

  Thus, when the system control unit 21 determines that the release button has been pressed, the imaging control unit 6 performs light control (more specifically, for light control of main light emission) based on a command from the system control unit 21. The image sensor 5 is controlled to perform exposure for pre-emission (step S52).

  When the exposure is completed, the pre-flash image is read from the image sensor 5 (step S53).

  From the read pre-emission image, photometric data is extracted by the image processing unit 9, and photometric calculation is performed by the exposure control unit 10 based on the extracted photometric data to calculate a photometric value. The system control unit 21 determines the flash emission amount of the main light emission based on the photometric value calculated by the exposure control unit 10 (step S54).

  Subsequently, the still image is exposed by global reset and global transfer (step S55).

  Then, a gain (still image sensitivity) necessary to amplify the image signal read out from the image sensor 5 by performing the still image exposure in step S55 is set (step S56).

  Next, the system control unit 21 determines whether or not the continuous shooting mode is set and the release button of the operation unit 14 is kept pressed (whether or not there is a continuous shooting instruction) (step S1). S57).

  If it is determined here that there is a continuous shooting instruction, the first divided readout of the still image exposed in step S55 or step S61 described later is performed, and the exposure for dimming is preliminarily performed during the exposure. This is performed while emitting light (step S58).

  When the exposure for light control is thus completed, the pre-flash image is read in the subsequent vertical synchronization period (step S59).

  Then, based on the photometric data extracted from the pre-flash image read in step S59, the exposure control unit 10 performs photometric calculation, and the system control unit 21 determines the flash emission amount of the main flash ( Step S60).

  Subsequently, the second still reading of the still image exposed in step S55 or the still image exposed when step S61 was executed last time and the next still image exposure are performed (step S61). ).

  In step S61, a gain (still image sensitivity) for reading a newly exposed still image is set (step S62), and then the process returns to step S57.

  On the other hand, if it is determined in step S57 that there is no continuous shooting instruction, if there is an image signal that has not been read, the image signal is read (step S63). Note that the reading of the still image in step S63 is not necessarily limited to the divided reading. In this way, when the image signal is read out, this process is terminated.

  According to the third embodiment, it is possible to perform exposure for dimming while dividing and reading still images, and to perform flash light emission amount control for exposing the next or subsequent still images. At this time, if the pre-emission performed between the two consecutive first exposure controls is performed once, the period for preparing the emission for the main emission is set as the first readout control period (divided readout of still images). Period) and at least a part of the pre-light emission is performed twice or more, and when the pre-light emission or the second light emission preparation or the main light emission preparation is performed, the first read control period is set. Since at least a part of the images can be overlapped, the time until the next still image can be photographed as compared with the case where the exposure for dimming is performed after the still image is read once without division. Can be shortened. As a result, it is possible to increase the number of images that can be continuously shot per unit time.

  Note that the shooting condition determined by the shooting condition determination unit based on the image signal read by the second reading control is often used mainly for the next first exposure control, for example. However, as described in each of the above-described embodiments, the determined shooting condition may be continuously used for the first exposure control after the next time.

  Furthermore, in each of the above-described embodiments, moving image shooting, photometry shooting, IAF shooting, and dimming shooting are performed in the interval between divided reading of still images, but two or more of these are performed. It may be performed in an appropriate order for each short-cycle vertical synchronization period, or may be performed as long as two or more of these can be executed within one short-cycle vertical synchronization period. Or when two or more can be performed simultaneously based on the image data obtained by one reading, they may be performed in combination. For example, since the image signal acquired for a moving image can be used for photometry at the same time, photometry can be performed while displaying a moving image without interruption during divided readout of a still image.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, you may delete some components from all the components shown by embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined. Thus, it goes without saying that various modifications and applications are possible without departing from the spirit of the invention.

1 ... Lens (Lens part)
2. Lens control unit (lens unit)
3 ... Aperture (aperture part)
4. Aperture control unit (aperture unit)
DESCRIPTION OF SYMBOLS 5 ... Imaging device 6 ... Imaging control part 7 ... A / D conversion part 8 ... Volatile memory 9 ... Image processing part 10 ... Exposure control part (Shooting condition determination part, exposure condition determination part)
11. AF processing unit (imaging condition determining unit, focus condition determining unit)
DESCRIPTION OF SYMBOLS 12 ... External memory 13 ... Display part 14 ... Operation part 15 ... Non-volatile memory 16 ... Flash control part (flash part)
17 ... Flash charging part (flash part)
18 ... Flash light emitting part (flash part)
DESCRIPTION OF SYMBOLS 19 ... Power supply control part 20 ... Power supply part 21 ... System control part (Shooting condition determination part, flash emission amount determination part, focus condition determination part)

Claims (4)

In an imaging device that obtains an image signal by performing exposure,
An image sensor having a memory in which a plurality of pixels that generate signal charges according to the exposure amount are two-dimensionally arranged and stores image signals of all pixels;
First exposure control for causing the image sensor to perform a first exposure, and storing image signals of all pixels of the image sensor subjected to the first exposure in the memory, and storing all the image signals stored in the memory A first readout control for sequentially reading out image signals of pixels for each field, a second exposure control for causing the image sensor to perform a second exposure, and two sequential orders in the first readout control. A second readout control for reading out an image signal related to the second exposure control from at least a part of pixels included in a field in which readout by the first readout control is completed during a field readout period; An imaging control unit to perform;
A shooting condition determining unit that determines a shooting condition related to the first exposure control for the next time or later based on the image signal read by the second reading control;
An imaging apparatus comprising: It further comprises a diaphragm that mechanically controls the passage range of the light beam reaching the image sensor,
The imaging condition determining unit is configured to set an exposure condition including an aperture value of the aperture unit as an imaging condition related to the first exposure control for the next time or thereafter based on the image signal read by the second readout control. An exposure condition determining unit for determining,
2. The period for changing the aperture value of the aperture section related to the first exposure control at or after the next time is at least partially overlapped with the first readout control period. Imaging device. It further comprises a flash unit that performs flash emission,
The imaging condition determination unit causes the flash unit to perform pre-emission during the second exposure control period, and based on an image signal read by the second read control, the first or subsequent first time A flash emission amount determining unit for determining the flash emission amount of the main emission as a photographing condition related to the exposure control of
In the case where the pre-emission is performed once between two consecutive first exposure controls, the period for preparing the main emission is at least partially overlapped with the first readout control period. In the case where the pre-emission is performed twice or more, a period for preparing the pre-emission or the main emission for the second or subsequent times at least partially overlaps the first readout control period. The imaging apparatus according to claim 1, wherein: A subject image is formed on the image sensor, and further includes a lens unit capable of adjusting a focus position,
The imaging condition determining unit moves the focus position of the lens unit after the first exposure control is completed, and based on the image signal read by the second read control, the next time or later A focus condition determining unit that determines a focus position of the lens unit serving as a focus position as a shooting condition according to the first exposure control;
The change of the focus position of the lens unit for determining the in-focus position, or the change of the focus position of the lens unit related to the first exposure control at or after the next time is at least in the first readout control period. The imaging apparatus according to claim 1, wherein the imaging apparatus partially overlaps.

Images