JP2013179488A - Imaging apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of controlling an exposure period by properly selecting an electronic shutter or a mechanical shutter.SOLUTION: The imaging apparatus comprises: an imaging device for receiving an incident beam; the mechanical shutter capable of mechanically cutting off or opening an incident light path to the imaging device; and a selection unit which selects, on the basis of the movement of a subject, first control of controlling the exposure period with the electronic shutter of the imaging device or second control of controlling the exposure period with the mechanical shutter, as control of the exposure period when imaging the subject corresponding to the beam incident to the imaging element.

Description

  The present invention relates to an imaging apparatus and a program.

  There is an image pickup apparatus that includes an electronic shutter that controls the charge accumulation time of the image pickup device and a mechanical shutter that mechanically blocks and opens an incident optical path to the image pickup device. (For example, refer to Patent Document 1).

JP 2006-345317 A

  By the way, as an electronic shutter of an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) sensor, for example, a rolling shutter system that sequentially shifts the charge accumulation time for each line in the vertical direction is generally used. When the exposure time is controlled by this rolling shutter type electronic shutter, there is an advantage that power consumption can be suppressed because there is no need to drive a mechanical shutter, but distortion occurs in an image when a fast-moving subject is photographed. There was a problem that there was. On the other hand, when the exposure time is controlled by the mechanical shutter, there is an advantage that generation of the above-described image distortion can be suppressed, but there is a problem that power consumption is increased because electric power for driving the mechanical shutter is necessary. It was.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an imaging apparatus and a program for appropriately selecting either an electronic shutter or a mechanical shutter to control an exposure time. .

  The present invention has been made to solve the above-described problems, and the present invention includes an image sensor that receives an incident light beam, a mechanical shutter that can mechanically block and open an incident optical path to the image sensor, A first control for controlling an exposure time by an electronic shutter of the image sensor based on a movement of the subject, and a control of an exposure time when the subject is imaged according to a light beam incident on the image sensor; and An image pickup apparatus comprising: a selection unit that selects which of the second controls for controlling the exposure time by a mechanical shutter.

  According to another aspect of the present invention, a computer having an imaging device that receives an incident light beam and a mechanical shutter that can mechanically block and open an optical path incident on the imaging device is incident on the imaging device. The exposure time when the subject is imaged according to the luminous flux is controlled, the first control for controlling the exposure time by the electronic shutter of the image sensor based on the movement of the subject, and the exposure time by the mechanical shutter. This is a program for executing a selection step of selecting which of the second controls to be controlled.

  According to the present invention, the exposure time can be controlled by appropriately selecting either the electronic shutter or the mechanical shutter.

1 is a schematic block diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention. It is a schematic block diagram which shows an example of a structure of a process part. It is a figure explaining schematic structure of an image sensor, and operation of an electronic shutter. It is a figure explaining the outline | summary of the exposure operation | movement by electronic shutter mode. It is a figure explaining an example of the image acquired by exposure operation by electronic shutter mode. It is a figure explaining the outline | summary of the exposure operation | movement by mechanical shutter mode. It is a flowchart which shows an example of the shutter mode selection process by 1st Embodiment. It is a flowchart which shows an example of the shutter mode selection process by 2nd Embodiment. It is a flowchart which shows an example of the shutter mode selection process by 3rd Embodiment. It is a flowchart which shows another example of the shutter mode selection process by 3rd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
(Configuration of imaging device)
FIG. 1 is a schematic block diagram showing a configuration of an imaging apparatus 300 according to an embodiment of the present invention. Here, the imaging apparatus 300 is an interchangeable lens type imaging apparatus including the camera body 100 and the interchangeable lens 200.

  The interchangeable lens 200 includes a lens unit 201 and a diaphragm unit 202. The lens unit 201 includes, for example, a plurality of lenses such as a zoom lens, a focus adjustment lens, and an anti-vibration lens. The aperture unit 202 includes, for example, an aperture mechanism having a plurality of aperture blades and a drive unit that drives the aperture mechanism, and the aperture diameter of the aperture can be changed. By controlling the aperture diameter of the aperture mechanism, the aperture unit 202 controls the amount of light beam (subject light) incident through the lens unit 201 and enters the camera body 100.

  The camera body 100 includes a mechanical shutter 101, a shutter drive unit 102, an image sensor 103, a lens control unit 104, a shooting control unit 105, a memory unit 106, a battery unit 107, and a display unit 108. Yes.

  The mechanical shutter 101 has a shutter mechanism capable of mechanically blocking and opening an incident optical path of a light beam incident through the interchangeable lens 200 to the image sensor 103. For example, the mechanical shutter 101 has a shutter mechanism including a shutter curtain, and mechanically blocks or opens the incident optical path to the image sensor 103 by driving the shutter drive unit 102 to open and close the shutter curtain. To do. That is, the mechanical shutter 101 is a mechanical shutter that adjusts the exposure time of the imaging surface (light receiving surface) of the image sensor 103.

  For example, the shutter curtain described above is formed by a thin plate-like member that slides and moves in a plane orthogonal to the optical axis 10 of the incident light beam. Then, the mechanical shutter 101 mechanically blocks (closes the shutter) or opens (opens the shutter) the optical path to the image sensor 103 by sliding the shutter curtain by driving the shutter driving unit 102.

  The mechanical shutter 101 is a normally open shutter that mechanically blocks the incident optical path (closes the shutter) only at the timing of the start and end of exposure in still image shooting. That is, the shutter is open during shooting standby before the still image shooting process is executed, and subject light is incident on the image sensor 103 via the interchangeable lens 200.

  The shutter drive unit 102 drives the shutter mechanism (shutter curtain) of the mechanical shutter 101. For example, the shutter drive unit 102 has an electromagnet motor for sliding the shutter curtain. The shutter driving unit 102 mechanically blocks or opens the incident optical path to the image sensor 103 by driving the shutter mechanism (shutter curtain) of the mechanical shutter 101 under the control of the imaging control unit 105.

  The image sensor 103 receives a light beam incident through the interchangeable lens 200, photoelectrically converts the received light beam (subject light) into an analog image signal, and supplies the analog image signal to the processing unit 110. The image sensor 103 is driven under the control of the imaging control unit 105.

  The lens control unit 104 controls the lens unit 201 and the aperture unit 202 under the control of the imaging control unit 105. For example, the lens control unit 104 transmits a control signal for controlling a driving unit that drives a zoom lens, a focus adjustment lens, a vibration-proof lens, and the like included in the lens unit 201, and the interchangeable lens 200. Lens information and information indicating the control state of each lens are received. The lens control unit 104 transmits a control signal for controlling a driving unit that drives the diaphragm mechanism (diaphragm blade) of the diaphragm unit 202 and receives information (aperture value) indicating the aperture diameter of the diaphragm.

  The imaging control unit 105 controls driving of the image sensor 103 and driving of the shutter driving unit 102. Further, the imaging control unit 105 controls the driving of the lens unit 201 and the aperture unit 202 included in the interchangeable lens 200 via the lens control unit 104.

  For example, the imaging control unit 105 controls the driving of the imaging element 103, the shutter driving unit 102, the lens unit 201, and the aperture unit 202 in accordance with the imaging execution command and imaging conditions received from the processing unit 110. Then, the photographing process for acquiring the photographed image is executed. In addition, the imaging control unit 105 controls driving of each unit described above in accordance with a control command received from the processing unit 110, thereby obtaining a through image, focus adjustment control, and setting imaging conditions in the processing unit 110. Metering control to perform the above.

  Here, the through image is an image (live view image that is updated in real time) that is continuously acquired based on the light beam received by the image sensor 103 and that is, for example, an exposure in a photographing process. It is an image displayed on the display unit 108 for angle of view confirmation before starting, or an image used for focus adjustment and photometry control.

  The memory unit 106 includes a card connector to which a storage medium (card memory or the like) can be attached and detached, and performs writing (recording), reading, or erasing of an image or information on the attached storage medium. Note that the memory unit 106 may include a memory IC (Integrated Circuit) mounted inside the imaging apparatus 300.

  The battery unit 107 is configured to be able to store a battery such as a lithium ion secondary battery or a nickel hydride secondary battery, and images are taken from the stored battery via a battery terminal provided in the battery unit 107. Electric power necessary for the operation of each unit included in the apparatus 300 is supplied. Note that the battery that can be stored in the battery unit 107 may be a primary battery such as an alkaline battery.

  The display unit 108 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or the like, and displays an image or information supplied from the processing unit 110.

(Configuration of processing unit)
The processing unit 110 executes shooting processing, display processing, recording processing, and the like in the imaging apparatus 300. Next, the configuration of the processing unit 110 will be described in detail with reference to FIG. FIG. 2 is a schematic block diagram illustrating an example of the configuration of the processing unit 110.

  The processing unit 110 includes an A / D conversion unit 111, a subject detection unit 112, a motion detection unit 113, a shutter mode selection unit 114 (selection unit), an imaging condition setting unit 115, an image processing unit 116, and a display. A control unit 117 and a remaining battery level detection unit 118 are provided.

  The A / D conversion unit 111 converts the analog image signal supplied from the image sensor 103 into a digital image signal. Further, the A / D conversion unit 111 supplies the converted digital image signal to the subject detection unit 112, the imaging condition setting unit 115, or the image processing unit 116. The A / D conversion unit 111 may be included in the image sensor 103.

  The subject detection unit 112 detects an image of the subject from the image signal supplied from the A / D conversion unit 111. That is, the subject detection unit 112 detects an image of a subject from an image photographed (captured) via the image sensor 103.

  For example, the subject detection unit 112 uses the image signal supplied from the A / D conversion unit 111 to feature information (for example, facial feature information) indicating the characteristics of a person as a main subject (main subject) or a vehicle. An image of the main subject is detected based on feature information indicating features of the car (car, train, aircraft, etc.). Note that the subject detection unit 112 detects an image of the main subject from the through image.

  Here, the above-described features include a specific color, a specific shape, or an image of a specific portion having a specific positional relationship that is a feature of the main subject to be detected. For example, the subject detection unit 112 pattern-matches information indicating features detected from these images with a database (for example, a face database, a vehicle database, etc.) in which feature information of the main subject is registered. Is detected.

  The motion detection unit 113 is a feature included in the subject image detected by the subject detection unit 112 from each frame image of the through images (frame images continuous in time series) captured through the image sensor 103. Extract points. Then, the motion detection unit 113 detects a motion vector (motion) of the subject based on the inter-frame displacement of the extracted feature points.

  For example, the motion detection unit 113 determines the position of the main subject relative to the frame image region based on the displacement (displacement amount, displacement direction) of the position between the frames of the feature points (extracted feature points) included in the main subject relative to the frame image region. The motion vector of the image is detected.

  Further, the motion detection unit 113 determines whether or not the main subject is stopped based on the detected magnitude of the motion vector of the main subject. For example, the motion detection unit 113 is configured such that the magnitude of the displacement amount per unit time of the feature point included in the image of the main subject (that is, the magnitude of the motion vector and the speed of motion per unit frame) is the first threshold In the following cases, it is determined that the movement of the main subject has stopped (no movement). On the other hand, when the amount of displacement per unit time of the feature point included in the image of the main subject is larger than the first threshold, the motion detection unit 113 does not stop the movement of the main subject (there is motion). Is determined.

  Here, the first threshold is a threshold set in advance in order to determine whether or not the speed of movement of the main subject is a speed at which the main subject image is distorted (conspicuous) in the captured image. is there. This image distortion will be described later.

  The motion detection unit 113 determines whether or not the main subject has stopped in a predetermined direction (whether or not it is moving) based on the detected direction and magnitude of the motion vector of the main subject. May be. For example, the motion detection unit 113 determines that the main subject is in the horizontal direction (lateral direction) based on the size of the motion vector in the horizontal direction (reading line direction (horizontal line direction) of the image sensor) with respect to the image area of the through image. It may be determined whether or not the vehicle has stopped. Also, the motion detection unit 113 determines whether the main subject has stopped in the vertical direction (vertical direction) based on the magnitude of the motion vector in the vertical direction with respect to the image area of the through image. Good.

  Note that the motion detection unit 113 may detect the main subject from all the frame images continuous in time series of the through images, or may detect it from the frame images at predetermined frame intervals. In this way, the motion detection unit 113, for example, determines the position of the image of the main subject (position relative to the image area of the frame image) detected in the frame image at a certain time as the next frame image (or the subsequent frame image). , It is determined that the main subject is moving (not stopped) when it is detected at a position (shifted position) different from the previous position.

  The shutter mode selection unit 114 controls the exposure time when the subject is imaged according to the light flux incident on the image sensor 103, and controls the exposure time by the electronic shutter of the image sensor 103 based on the movement of the subject. 1, and second control for controlling the exposure time by the mechanical shutter 101 is selected.

  In the following description, an operation mode in which the imaging apparatus 300 performs a shooting operation using the first control that controls the exposure time using the electronic shutter of the imaging element 103 is referred to as an electronic shutter mode. In addition, an operation mode in which the imaging apparatus 300 performs a shooting operation using the second control in which the exposure time is controlled by the mechanical shutter 101 is referred to as a mechanical shutter mode.

  That is, the shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the movement of the main subject to be photographed. For example, the shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on whether or not the main subject to be photographed is moving.

  Specifically, when the motion detection unit 113 determines that the motion of the main subject has stopped based on the detected motion vector of the main subject, the shutter mode selection unit 114 selects the electronic shutter mode. On the other hand, when the motion detection unit 113 determines that the motion of the main subject has not stopped based on the detected motion vector of the main subject, the mechanical shutter mode is selected. In addition, the shutter mode selection unit 114 supplies a selection signal indicating the selected shutter mode to the imaging control unit 105.

  Note that the imaging apparatus 300 includes, for example, an operation input unit (not shown, which may be an operation input unit using a selection menu screen displayed on the display unit 108, for example) capable of selecting a shutter mode. May be. Then, the imaging apparatus 300 can be selected by the user from three types of shutter modes: “select electronic shutter mode”, “select mechanical shutter mode”, or “automatically select either electronic shutter mode or mechanical shutter mode”. It may be configured as possible. In this case, when “automatic selection of either electronic shutter mode or mechanical shutter mode” is selected, the shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the movement of the main subject. The process of selecting is executed. The shutter mode selection process for selecting either the electronic shutter mode or the mechanical shutter mode will be described later in detail.

  The shooting condition setting unit 115 sets shooting conditions when the shooting control unit 105 executes shooting processing. The photographing conditions are set conditions such as shutter speed (exposure time), aperture value, sensitivity, and the like. Specifically, the imaging condition setting unit 115 performs photometry processing using the image signal (through-image image signal) supplied from the A / D conversion unit 111 so that an appropriate exposure amount can be obtained. Shooting conditions such as shutter speed (exposure time), aperture value, or sensitivity are determined. Further, the shooting condition setting unit 115 supplies a setting signal for setting the determined shooting condition to the shooting control unit 105. Note that the shooting condition setting unit 115 may also supply a setting signal for setting the determined shooting condition to the shutter mode selection unit 114.

  The image processing unit 116 performs image processing on an image captured via the image sensor 103. For example, the image processing unit 116 performs image quality processing such as white balance adjustment, sharpness adjustment, gamma correction, and gradation adjustment on the image signal of the still image supplied from the A / D conversion unit 111, and JPEG Perform image compression processing such as (Joint Photographic Experts Group). Then, the image processing unit 116 supplies the image data generated through the image quality processing and the image compression processing to the memory unit 106 for storage.

  The image processing unit 116 performs image quality processing for display on the still image signal and the through image signal supplied from the A / D conversion unit 111, and converts the image signal to a display image signal. And supplied to the display control unit 117.

  The display control unit 117 converts the image signal received from the image processing unit 116 into a display signal in accordance with a format for displaying on the display unit 108 and causes the display unit 108 to display an image. In addition to the image, the display control unit 117 may display a setting menu for operation input and information indicating shooting conditions on the display unit 108. For example, the display control unit 117 may display information indicating the shooting condition on the display unit 108 based on the setting signal output from the shooting condition setting unit 115.

  The remaining battery level detection unit 118 detects the remaining capacity of the battery stored in the battery unit 107. For example, the battery remaining amount detection unit 118 detects the remaining battery capacity by detecting the battery voltage of the battery unit 107. Further, the remaining battery level detection unit 118 supplies the detection result to the shutter mode selection unit 114.

(Explanation of shutter mode selection processing)
Next, shutter mode selection processing in the imaging apparatus 300 will be described.
First, an outline of control of exposure time control by the electronic shutter of the image sensor 103 and exposure time control by the mechanical shutter 101 will be described with reference to FIGS.

First, the control of the exposure time by the electronic shutter will be described with reference to FIGS. FIG. 3 is a diagram for explaining the schematic configuration of the image sensor 103 and the operation of the electronic shutter.
The image sensor 103 includes a CMOS sensor. A plurality of pixels are two-dimensionally arranged in the pixel region 20 (all pixel regions of the image sensor 103) on the image pickup surface of the image sensor 103 shown in this figure.

  Further, the image sensor 103 includes a horizontal scanning unit 30 and a vertical scanning unit 40, and accumulates according to light received by each pixel in the pixel region 20 by driving the horizontal scanning unit 30 and the vertical scanning unit 40. The generated charge is output.

  The vertical scanning unit 40 includes a vertical scanning circuit for readout including a shift register that sequentially selects readout pixel lines (horizontal pixel lines, pixel rows) in the pixel region 20 in the vertical direction, and starts accumulation of each pixel. And a vertical scanning circuit for shutter including a shift register for sequentially selecting pixel lines for (shutter) in the vertical direction.

  Exposure is started at each pixel of the exposure start line 21 selected at the accumulation start (shutter) timing of pulses sequentially shifted in the vertical direction indicated by reference numeral 42. Further, the accumulated charge is read out in each pixel of the readout line 22 selected at the readout timing of the pulse sequentially shifted in the vertical direction indicated by reference numeral 41. The image sensor 103 performs an electronic shutter operation by the vertical scanning circuit for shutter and the vertical scanning circuit for reading.

  For example, for each pixel in the pixel area 20, a pixel line (exposure start line 21) at which exposure is started is selected for each pixel line at an accumulation start (shutter) timing (reference numeral 42). For each pixel in the pixel region 20, a pixel line (read line 22) from which accumulated charges are read is selected for each pixel line at a read timing (reference numeral 41). That is, the exposure time (accumulation time) for each pixel line by the electronic shutter is the time from the exposure start line 21 to the readout line 22 (corresponding to the time indicated by reference numeral 23).

  The vertical scanning unit 40 sequentially shifts the exposure start line 21 and the readout line 22 by the electronic shutter in the vertical direction. Then, the exposure start line 21 and the readout line 22 are shifted (scanned) from the first pixel line to the last pixel line, thereby exposing all the pixels in the pixel region 20 (ie, exposure for one screen). Is completed.

  Further, the horizontal scanning unit 30 sequentially scans the charges of the pixels of the pixel lines that are sequentially selected and exposed in the vertical direction under the control of the vertical scanning unit 40 in the horizontal direction, and outputs them as analog pixel signals. The charge of each pixel that is sequentially scanned in the horizontal direction and output by the horizontal scanning unit 30 is, for example, not shown, but an amplifier that amplifies the accumulated charge for each pixel and the amplifier for each pixel. This charge is temporarily stored in the buffer via a CDS (correlated double sampling) circuit for removing output variations.

  FIG. 4 is a view for explaining the outline of the exposure operation in the electronic shutter mode. As described with reference to FIG. 3, according to the electronic shutter operation of the image sensor 103, exposure for each pixel line is sequentially shifted from the first pixel line to the last pixel line (rolling shutter method). Therefore, the exposure timing of the first pixel line is gradually shifted from the exposure timing of the last pixel line.

  FIG. 4A shows the pixel area 20, and FIG. 4B shows each pixel line in the pixel area 20 with the vertical axis representing the vertical position and the horizontal axis representing time t (exposure timing). The exposure timing is shown. The exposure timing of the area 51 shown in FIG. 4A is sequentially delayed from the first pixel line to the last pixel line as shown in the accumulation start (shutter) timing 52 and the readout timing 53 shown in FIG. To go.

  For example, the pixel region 61 in the first predetermined pixel line in the pixel region 20 shown in FIG. 4A is the same as the pixel region 61 in the horizontal direction and the last predetermined pixel line. There is a difference between the respective exposure timings of the pixel region 62 in FIG. As shown in FIG. 4B, the timing at which the subject light is exposed to the pixel area 62 is delayed with respect to the timing at which the subject light is exposed to the pixel area 61.

  As described above, since the exposure timing for each pixel line in the vertical direction is sequentially delayed, for example, when a fast moving subject is photographed, the position of the subject at the exposure timing of each pixel line changes. May be distorted.

  FIG. 5 is a diagram for explaining an example of an image taken by the exposure operation in the electronic shutter mode. FIG. 5A shows the movement of a subject received by the pixel region 20 when a person is photographed as a main subject. In this figure, the person who is the main subject is moving at a high speed in the horizontal direction (the same direction as the horizontal direction and the horizontal scanning direction), and the position where the person's subject light is received is changed from the position indicated by reference numeral 71 to reference numeral 72. The state which is moving to the position shown at high speed is shown.

  Here, the pixel area 61 shown in FIG. 5A is an area where a light beam incident from a position above the person's head when the person who is the main subject is at the position indicated by reference numeral 71 is received. The pixel area 62a is an area where a light beam incident from the position of the person's foot when the person who is the main subject is at the position indicated by reference numeral 71 is received. The pixel region 62b is a region where a light beam incident from the position of the person's foot when the person who is the main subject is at the position indicated by reference numeral 72 is received.

  Then, it is assumed that a person who is a main subject is photographed with an exposure time including a time during which the person as a main subject moves at a high speed from the position indicated by reference numeral 71 to the position indicated by reference numeral 72 in the electronic shutter mode. By this exposure for photographing, for example, a light beam received by the pixel area 61 in FIG. 5A is exposed (accumulated) in the pixel area 61 shown in FIG. 5B. However, since the exposure timing is sequentially delayed in the vertical direction, the pixel region 62 shown in FIG. 5B is not a light beam received by the pixel region 62a in FIG. In some cases, the light beam received by the pixel region 62b is exposed (accumulated).

  In this case, since the position of the person as the main subject moves as the exposure timing sequentially delays in the vertical direction, the diagonal line connecting the pixel area 61 and the pixel area 62 as shown in FIG. The subject light of the person is exposed to each pixel in the pixel region that is sequentially shifted in the direction. As a result, the image of the person who is the main subject is photographed as a distorted image that is gradually shifted obliquely in the vertical direction.

  Although the image distortion in the case where the main subject moves in the horizontal direction (horizontal direction, horizontal scanning direction in the image sensor 103, pixel line direction) has been described with reference to FIG. In some cases, the captured image may be affected. For example, when the main subject moves in the vertical direction (vertical direction, vertical scanning direction in the image sensor 103), the length of the main subject in the vertical direction may be shortened.

  However, when the length of the main subject in the vertical direction is shortened, it is often less noticeable than when the above-described image is distorted. When the main subject moves in an oblique direction, the influence on the image (image distortion) depends on the horizontal (horizontal) size and the vertical (vertical) size of the motion vector of the main subject. Or changes in vertical length).

  On the other hand, in the exposure time control in the mechanical shutter mode, the above-described image distortion is suppressed by mechanically controlling the start and end of the exposure time at a speed faster than the vertical scanning time by the electronic shutter. can do.

  Subsequently, the control of the exposure time by the mechanical shutter 101 will be described with reference to FIG. FIG. 6 is a diagram for explaining the outline of the exposure operation in the mechanical shutter mode, in which the vertical axis represents the vertical position of the pixel region 20 and the horizontal axis represents time t (exposure timing).

  Each pixel accumulates the received light beam during the time between the accumulation start (shutter) timing 52 and the readout timing 53. However, the time from the accumulation start (shutter) timing 52 to the mechanical shutter opening timing 54 (timing to open the mechanical shutter) and the time from the mechanical shutter closing timing 55 (timing to close the mechanical shutter) to the reading timing 53 (hatched portion shown in FIG. 6). ), Since the light flux to the image sensor 103 is blocked by the mechanical shutter 101, no subject light is accumulated in each pixel.

  That is, the exposure time is the time during which the mechanical shutter 101 is opened from the mechanical shutter opening timing 54 to the mechanical shutter closing timing 55. Therefore, if the mechanical shutter 101 operates fast, image distortion that may occur in the electronic shutter operation does not occur.

  Thus, in the mechanical shutter mode, there is an advantage that image distortion that may occur in the electronic shutter mode can be suppressed. On the other hand, in the mechanical shutter mode, power for operating the mechanical shutter 101 at a mechanically high speed is required. There is a problem in that the power consumption of the battery (battery stored in the battery unit 107) included in the imaging apparatus 300 is accelerated by this power.

  On the other hand, in the electronic shutter mode described above, there is a problem that the image may be distorted depending on the movement of the subject. However, since the mechanical shutter 101 does not need to be mechanically operated, the power can be kept low. There is.

  As described above, the electronic shutter mode and the mechanical shutter mode have advantages and disadvantages that conflict with each other. Therefore, the imaging apparatus 300 according to the present embodiment executes a process of selecting a suitable mode from the electronic shutter mode and the mechanical shutter mode based on the movement of the subject.

(Explanation of shutter mode selection processing)
Next, the operation of the shutter mode selection process in which the imaging apparatus 300 selects either the electronic shutter mode or the mechanical shutter mode will be described.

  This shutter mode selection process is performed in the imaging apparatus 300 when, for example, “automatic selection of either the electronic shutter mode or the mechanical shutter mode” is selected as the shutter mode, that is, the shutter mode is not specified by the user. It is executed in the operation selected by the control of the imaging apparatus 300. In addition, this processing is performed through the image sensor 103 in the shooting standby state before the start of exposure in the shooting processing (for example, before the shutter button is pressed or before the start of exposure immediately after the shutter button is pressed). It is a process that is executed when acquiring.

  FIG. 7 is a flowchart illustrating an example of shutter mode selection processing according to the first embodiment. The imaging apparatus 300 shown in this figure detects the movement of the subject from the through image acquired via the imaging element 103, and selects the shutter mode based on the detected movement of the subject. Hereinafter, the operation of the shutter mode selection process will be described with reference to FIG.

  First, the A / D conversion unit 111 converts an analog image signal (output image signal of the image sensor 103, image signal of a through image) supplied from the image sensor 103 into a digital image signal, and converts the image. A signal is supplied to the subject detection unit 112 (step S11).

  Next, the subject detection unit 112 detects an image of a subject (for example, a main subject) from the image signal supplied from the A / D conversion unit 111 (step S12).

  Subsequently, the motion detection unit 113 extracts feature points included in the image of the main subject detected by the subject detection unit 112 from each frame image of the through images captured through the image sensor 103. Then, the motion detection unit 113 detects a motion vector (motion) of the subject based on the inter-frame displacement of the extracted feature points. Then, based on the detected motion vector of the main subject, the motion detection unit 113 determines whether or not the subject is moving in the lateral direction (horizontal direction) (whether there is a lateral motion) (step S13). ).

  If it is determined in step S13 that the main subject is moving in the horizontal direction (there is horizontal movement), the shutter mode selection unit 114 selects the mechanical shutter mode (step S16). On the other hand, when it is determined in step S13 that the main subject does not move in the horizontal direction (no movement in the horizontal direction), the shutter mode selection unit 114 selects the electronic shutter mode (step S17).

  As described above, the processing unit 110 selects the shutter mode based on the movement of the subject detected from the through image, and ends the shutter mode selection process.

  As a result, the imaging apparatus 300 selects the mechanical shutter mode when the subject to be photographed (for example, the main subject) moves (for example, when it moves in the horizontal direction at a high speed), so that the photographed image is displayed. It is possible to suppress distortion in the image of the main subject included.

  In addition, the imaging apparatus 300 can select the electronic shutter mode when the subject to be photographed (for example, the main subject) does not move because the above-described image distortion does not occur. That is, the imaging apparatus 300 can reduce power consumption because there is no need to operate the mechanical shutter 101 by selecting the electronic shutter mode when the subject to be photographed (for example, the main subject) does not move. .

  Therefore, the imaging apparatus 300 can appropriately select one of the electronic shutter mode and the mechanical shutter mode based on the movement of the subject. That is, the imaging apparatus 300 can appropriately select either the electronic shutter or the mechanical shutter 101 to control the exposure time.

Second Embodiment
The second embodiment is a process in which a determination based on the shutter speed is added to the shutter mode selection process of the first embodiment.

  For example, when the shutter speed is slow (long time), even if the subject to be photographed moves in the horizontal direction, the effect of image blurring is large, so the effect of image distortion due to the electronic shutter operation is the effect of image blurring. The image distortion becomes less noticeable. In such a case, the imaging apparatus 300 according to the second embodiment suppresses the frequency of use of the mechanical shutter mode based on the speed (long / short) of the shutter speed.

  An imaging apparatus 300 according to the second embodiment has the same configuration as that shown in FIGS. The shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the shutter speed (exposure time length) when the subject is imaged. Specifically, the shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the detection result of the motion detection unit 113 and the shutter speed determined by the shooting condition setting unit 115.

  For example, when the electronic shutter mode is selected based on the detection result of the motion detection unit 113, the shutter mode selection unit 114 selects the electronic shutter mode without determining the shutter speed.

  On the other hand, when the shutter mode selection unit 114 selects the mechanical shutter mode based on the detection result of the motion detection unit 113, the shutter mode selection unit 114 further selects either the electronic shutter mode or the mechanical shutter mode based on the shutter speed.

  Specifically, for example, the shutter mode selection unit 114 is configured to detect the shutter speed (exposure time of the subject) even when the subject has not stopped moving (for example, moved in the horizontal direction). When the (length) is longer than the second threshold, the electronic shutter mode is selected.

  Here, the second threshold value is, for example, a value set in advance as a shutter speed threshold value that is highly likely to cause image blurring so that the influence of image distortion due to the electronic shutter is inconspicuous. It is. The second threshold value is one threshold value (for example, 1/60 seconds), a value based on the reciprocal of the focal length value according to the focal length, and the speed of movement of the subject (the magnitude of the motion vector, unit time) (Amount of displacement per round)) and a value based on the reciprocal of the value of the focal length, etc. Further, the second threshold value may be set based on the shake amount of the imaging apparatus 300 itself, the presence / absence of the image stabilization function, and the like.

  FIG. 8 is a flowchart illustrating an example of shutter mode selection processing according to the second embodiment. The process shown in FIG. 8 differs from the process shown in FIG. 7 in that the process of step S14 is added. In FIG. 8, processes corresponding to the processes in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted.

  If it is determined in step S13 that the main subject is moving in the horizontal direction (there is a horizontal movement), the shutter mode selection unit 114 sets the shutter speed based on the setting signal output from the shooting condition setting unit 115. Get the information shown. Then, based on the acquired information indicating the shutter speed, the shutter mode selection unit 114 determines whether or not the shutter speed is equal to or lower than the second threshold value (short time) (step S14).

  If it is determined in step S14 that the shutter speed is equal to or lower than the second threshold value, the shutter mode selection unit 114 selects the mechanical shutter mode (step S16). On the other hand, if it is determined in step S14 that the shutter speed is slower than the second threshold (long time), the shutter mode selection unit 114 selects the electronic shutter mode (step S17).

  As described above, the imaging apparatus 300 selects either the electronic shutter mode or the mechanical shutter mode based on the shutter speed (exposure time length) when the subject is imaged. For example, the shutter mode selection unit 114 can detect the shutter speed (the length of the exposure time) when the subject is imaged even when the movement of the subject is not stopped (for example, when the subject is moving in the horizontal direction at a high speed). ) Is longer than the second threshold, the electronic shutter mode is selected.

  As a result, the imaging apparatus 300 can detect the shutter speed (exposure) when the subject is imaged even if the subject to be photographed (for example, the main subject) moves (for example, when the subject is moving laterally at a high speed). When the time length is long (when the shutter speed at which image blur is likely to occur), it is possible to reduce the operation opportunity of the mechanical shutter 101 and reduce power consumption.

  The imaging apparatus 300 also moves the subject to be photographed (for example, the main subject) when it moves (for example, moves at a high speed in the horizontal direction), and the shutter speed (length of exposure time) when photographing the subject. ) Is short (when the shutter speed at which image blur hardly occurs), the mechanical shutter mode is selected, so that distortion of the main subject image included in the photographed image can be suppressed.

<Third Embodiment>
The third embodiment is a process in which determination based on the remaining battery capacity is added to the shutter mode selection process of the first embodiment or the second embodiment.

  For example, if the remaining battery level is low, even if the captured image is distorted, it may be better to shoot than to run out of battery capacity. In such a case, the imaging apparatus 300 according to the third embodiment restricts the use of the mechanical shutter mode based on the remaining battery capacity.

  An imaging apparatus 300 according to the third embodiment has the same configuration as that illustrated in FIGS. The shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the remaining battery capacity of the battery unit 107. Specifically, the shutter mode selection unit 114 selects either the electronic shutter mode or the mechanical shutter mode based on the remaining battery capacity of the battery unit 107 detected by the remaining battery level detection unit 118.

  For example, even when the movement of the subject is not stopped (for example, when moving in the horizontal direction), the shutter mode selection unit 114 is, when the remaining battery capacity of the battery unit 107 is less than the third threshold value, Select the electronic shutter mode.

  Here, the third threshold is, for example, the remaining capacity of the battery that can perform the photographing operation only a few times (for example, the capacity that is only 10% of the number of times that the photographing can be performed with a fully charged battery). Or a threshold value of the remaining battery capacity that can be executed if the photographing operation in the mechanical shutter mode is impossible and the photographing operation is in the electronic shutter mode.

  FIG. 9 is a flowchart illustrating an example of shutter mode selection processing according to the third embodiment. The process shown in FIG. 9 is different from the process shown in FIG. 7 in that the process of step S15 is added. In FIG. 9, processes corresponding to the processes in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted.

  If it is determined in step S13 that the main subject is moving in the horizontal direction (there is a horizontal movement), the shutter mode selection unit 114 detects the remaining battery level of the battery unit 107 detected by the battery level detection unit 118. Acquires information indicating the capacity. Then, based on the acquired information indicating the remaining battery capacity, the shutter mode selection unit 114 determines whether or not the remaining battery capacity is equal to or less than the third threshold (whether or not the remaining battery capacity is sufficient). Determination is made (step S15).

  If it is determined in step S15 that the remaining battery capacity is greater than the third threshold (the battery remaining capacity is sufficient), the shutter mode selection unit 114 selects the mechanical shutter mode (step S16). On the other hand, if it is determined in step S15 that the remaining battery capacity is equal to or less than the third threshold (there is no remaining battery capacity), the shutter mode selection unit 114 selects the electronic shutter mode (step S17). .

  As described above, the imaging apparatus 300 selects one of the electronic shutter mode and the mechanical shutter mode based on the remaining battery capacity of the battery unit 107. For example, the imaging apparatus 300 has a case where the remaining battery capacity of the battery unit 107 is less than the third threshold even when the movement of the subject is not stopped (for example, when moving in the horizontal direction at a high speed). The electronic shutter mode is selected.

  Thereby, even when the subject to be photographed (for example, the main subject) has a motion (for example, when it moves in the lateral direction at a high speed), the imaging apparatus 300 has a low battery capacity, The opportunity for operating the mechanical shutter 101 can be reduced to reduce power consumption.

  Note that the shutter mode selection unit 114 does not stop the movement of the subject (for example, when moving in the horizontal direction at a high speed) and the shutter speed is equal to or less than the second threshold value. When the remaining battery capacity of the battery unit 107 is less than the third threshold value, the electronic shutter mode may be selected. That is, the process shown in FIG. 8 may be a process obtained by adding the process of step S15.

  FIG. 10 is a flowchart showing another example of the shutter mode selection process according to the third embodiment. The process shown in FIG. 10 is a process in which the process of step S15 is added to the process shown in FIG. is there. In FIG. 10, processes corresponding to the processes in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

  If it is determined in step S14 that the shutter speed is equal to or lower than the second threshold value, the shutter mode selection unit 114 acquires information indicating the remaining battery capacity of the battery unit 107 detected by the battery remaining amount detection unit 118. . Then, based on the acquired information indicating the remaining battery capacity, the shutter mode selection unit 114 determines whether or not the remaining battery capacity is equal to or less than the third threshold (whether or not the remaining battery capacity is sufficient). Determination is made (step S15).

  If it is determined in step S15 that the remaining battery capacity is greater than the third threshold (the battery remaining capacity is sufficient), the shutter mode selection unit 114 selects the mechanical shutter mode (step S16). On the other hand, if it is determined in step S15 that the remaining battery capacity is equal to or less than the third threshold (there is no remaining battery capacity), the shutter mode selection unit 114 selects the electronic shutter mode (step S17). .

  As described above, the imaging apparatus 300 is a case where the movement of the subject is not stopped (for example, when moving in the horizontal direction at a high speed) and the shutter speed is equal to or less than the second threshold value. However, when the remaining battery capacity of the battery unit 107 is smaller than the third threshold value, the electronic shutter mode is selected.

  As a result, the imaging apparatus 300 is in a case where a subject to be photographed (for example, a main subject) is moving (for example, moving in a horizontal direction at a high speed), and the shutter speed is equal to or less than the second threshold value. Even if it is a case, when the remaining capacity of the battery is small, the operation opportunity of the mechanical shutter 101 can be reduced and the power consumption can be reduced.

  As described above, as described with reference to the first embodiment, the second embodiment, and the third embodiment, the imaging apparatus 300 can select either the electronic shutter mode or the mechanical shutter mode based on the movement of the subject. Can be selected appropriately. That is, the imaging apparatus 300 can appropriately select either the electronic shutter or the mechanical shutter 101 to control the exposure time.

  In the above embodiment, an example in which the main subject is mainly a person has been described, but the main subject is not limited to a person. For example, the main subject may be a living thing or a vehicle that is not limited to a person. In addition, the subject detection unit 112 may detect a subject located at the center within the shooting angle of view, a subject that occupies most of the area within the shooting angle of view, and the like as the main subject, or the subject designated by the user as the main subject. You may detect as a to-be-photographed object.

  In the above-described embodiment, the configuration in which the image sensor 103 includes a CMOS sensor has been described as an example. However, the present invention is not limited to this, and an electronic shutter method in which the exposure timing for each pixel line is sequentially shifted in the vertical direction. As long as the image sensor is an image sensor other than the configuration including the CMOS sensor, the image sensor may be used.

  In the above-described embodiment, the configuration in which the imaging apparatus 300 is an interchangeable lens imaging apparatus has been described as an example. However, the imaging apparatus 300 may be an imaging apparatus having a configuration in which lenses are integrated.

  In the above embodiment, the imaging apparatus 300 detects the feature point of the subject from the through image, and detects the motion vector of the detected feature point, so that the motion of the subject (for example, whether the motion has stopped). However, the present invention is not limited to this. For example, the imaging apparatus 300 may detect the movement of the subject by performing a motion capture process on the through image, or simply detect whether or not the subject is in a predetermined region of the image between the frames of the through image. Thus, the movement of the subject may be detected. Further, the imaging apparatus 300 may perform processing for detecting the motion of the subject using an ultrasonic motion detection sensor, a magnetic sensor, an infrared sensor, or the like instead of the processing for detecting the motion of the subject from the image.

  The processing unit 110 described above may be realized by dedicated hardware, and is configured by a memory and a CPU (central processing unit), and a program for realizing the functions of the processing unit 110 described above. The function may be realized by loading the program into a memory and executing it.

  Further, the above-described processing unit is recorded by recording a program for realizing the functions of the above-described processing unit 110 on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. 110 processing may be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 101 Image pick-up element 103 Mechanical shutter, 107 Battery part, 112 Subject detection part, 113 Motion detection part, 114 Shutter mode selection part (selection part), 300 Imaging device

Claims (11)

An image sensor for receiving an incident light beam;
A mechanical shutter capable of mechanically blocking and opening an incident optical path to the image sensor;
A first control for controlling an exposure time by an electronic shutter of the image sensor based on a movement of the subject, and a control of an exposure time when the subject is imaged according to a light beam incident on the image sensor; and A selection unit that selects which of the second controls for controlling the exposure time by the mechanical shutter;
An imaging apparatus comprising: The selection unit includes:
Selecting which of the first control and the second control is used as the exposure time control when imaging the subject based on whether or not the subject is stopped. The imaging apparatus according to claim 1. The selection unit includes:
When the movement of the subject is stopped, the first control is selected,
The imaging apparatus according to claim 1, wherein when the movement of the subject is not stopped, the second control is selected. Extracting feature points included in the image of the subject from each of the time-sequential frame images captured through the image sensor, and moving the subject based on the displacement of the extracted feature points between frames A motion detector for detecting
With
The selection unit includes:
Selecting one of the first control and the second control based on the movement of the subject detected by the motion detection unit before the start of exposure when imaging the subject. The imaging apparatus according to any one of claims 1 to 3, wherein The motion detector is
When the displacement amount per unit time of the feature point is less than or equal to a first threshold, it is determined that the movement of the subject is stopped, and the displacement amount per unit time of the feature point is The imaging apparatus according to claim 4, wherein when the movement is larger than the first threshold, it is determined that the movement of the subject is not stopped. A subject detection unit that detects an image of the subject from an image captured through the image sensor;
The imaging apparatus according to any one of claims 1 to 5, further comprising: The selection unit includes:
The control unit according to any one of claims 1 to 6, wherein one of the first control and the second control is selected based on a length of exposure time when the subject is imaged. The imaging device according to any one of the above. The selection unit includes:
Even if the movement of the subject is not stopped, the first control is selected if the length of the exposure time when imaging the subject is longer than a second threshold. Item 8. The imaging device according to any one of Items 1 to 7. A battery unit for supplying power,
With
The selection unit includes:
The control unit selects one of the first control and the second control based on a remaining capacity of the battery unit. Imaging device. The selection unit includes:
The imaging according to claim 9, wherein the first control is selected when the remaining capacity of the battery unit is less than a third threshold even when the movement of the subject is not stopped. apparatus. In a computer provided with an imaging device having an imaging device that receives an incident light beam, and a mechanical shutter that can mechanically block and open an incident optical path to the imaging device,
A first control for controlling an exposure time when the subject is imaged in accordance with a light beam incident on the image sensor, and an exposure time is controlled by an electronic shutter of the image sensor based on the movement of the subject; and A selection step for selecting which of the second controls for controlling the exposure time by the mechanical shutter is to be performed;
A program for running

Images