JP2019050594A - Image pickup apparatus, control method therefor, program and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an unnatural brightness with respect to a change in luminance of an object by acquiring an image obtained by intermittently imaging the object.
An imaging apparatus capable of setting a mode for performing intermittent imaging using an imaging unit, which comprises: a metering unit for metering a subject; and an intermittent imaging based on the metering result of the metering unit in the mode. Setting means for setting information on exposure corresponding to each of the detection means, and detection means for detecting, in the mode, first information on acquisition of a moving image obtained by joining a plurality of images acquired by intermittent imaging. And the setting means sets the information on the exposure by controlling the degree of smoothing of the exposure between successive imaging in the intermittent imaging based on the first information detected by the detection means. And
[Selected figure] Figure 3

Description

  The present invention relates to an imaging apparatus that performs intermittent imaging, its control method, program, and recording medium.

  Conventionally, so-called interval imaging is known as a technique for performing intermittent imaging at predetermined time intervals. In addition, a technique is known that acquires moving images (so-called time-lapse moving images) in which temporal changes in a subject are compressed and represented by connecting images acquired by performing intermittent imaging in the order of acquisition. ing. The time-lapse moving image has a reproduction time of a moving image acquired shorter than a period required from the start of the first imaging for the time-lapse moving image to the end of the last imaging.

  In patent document 1, when performing automatic exposure control for every imaging in interval photography, when viewing each frame continuously by the brightness changing a lot between the frames of imaging, (user) sense of incongruity The problem of being remembered has been raised. To address this problem, Patent Document 1 discloses a technique for smoothing the current proper exposure based on the history of the proper exposure obtained in the automatic exposure control process at the time of past imaging in the automatic exposure control process at interval shooting. Proposed.

JP, 2014-235183, A

  However, in the technique proposed in Patent Document 1, the exposure is uniformly smoothed without considering the environment (scene) at the time of imaging a subject and the imaging interval of interval imaging. Therefore, for example, when the imaging interval is relatively long and the ambient light changes significantly, the divergence of the exposure set at the time of imaging becomes large with respect to the actual luminance change of the subject. In this case, since the image for the time-lapse moving image is overexposed or underexposed with respect to the proper exposure corresponding to the brightness of the subject, the time-lapse moving image obtained by connecting the images is dark with respect to the brightness of the object Or a bright moving image is acquired.

  An object of the present invention is to suppress that an image acquired by capturing an image of a subject intermittently becomes unnatural brightness with respect to a change in luminance of the subject.

In order to achieve the above object, an image pickup apparatus according to the present invention is an image pickup apparatus capable of setting a mode for performing intermittent image pickup using an image pickup means, which comprises: a photometric means for photometrically measuring a subject; Setting means for setting information on exposure corresponding to each of intermittent imaging based on the photometry result of the photometry means;
A detection unit that detects, in the mode, first information related to acquisition of a moving image obtained by joining a plurality of images acquired by intermittent imaging; and the setting unit is configured to detect the first information detected by the detection unit. It is characterized in that information on the exposure is set by controlling the degree of smoothing of the exposure between successive imaging in intermittent imaging based on the first information.

  According to the present invention, it is possible to suppress that an image acquired by capturing an image of a subject intermittently becomes unnatural brightness with respect to a change in luminance of the subject.

It is a block diagram showing an example of composition of digital camera 1 which is an embodiment of an imaging device which carried out the present invention. It is a figure which illustrates an outline view (rear view) of camera 1 concerning the present invention by way of example. It is a flowchart explaining the imaging process in the time-lapse mode which concerns on this invention. It is a flow which shows exposure smoothing degree determination processing <A> concerning an embodiment of the present invention. It is a flowchart which shows the exposure arithmetic processing which concerns on this invention. It is a figure which illustrates an exposure smooth | blunted in the time-lapse mode which concerns on this invention. It is a figure which illustrates the relation between the difference of the number of exposure smoothed frames and the transition of the target exposure concerning the present invention. It is a flow which shows exposure smoothing degree determination processing <B> concerning a 2nd embodiment of the present invention. It is a flow which shows exposure smoothing degree determination processing <C> concerning a 3rd embodiment of the present invention.

(Embodiment)
(Basic configuration of digital camera 1)
Hereinafter, an embodiment of the present invention will be described based on the attached drawings. FIG. 1 is a block diagram showing a configuration example of a digital camera (hereinafter, simply referred to as a camera) 1 which is an embodiment of an imaging device according to the present invention. Note that one or more of the functional blocks shown in FIG. 1 may be realized by hardware such as an ASIC or programmable logic array (PLA), or realized by a programmable processor such as a CPU or MPU executing software. May be Also, it may be realized by a combination of software and hardware. Therefore, in the following description, even when different functional blocks are described as an operation subject, the same hardware can be realized as the subject.

  As illustrated in FIG. 1, the camera 1 of the present embodiment includes a camera body 100 and a lens unit 200. The lens unit 200 is freely attachable to and detachable from the camera body 100. The configuration of the camera 1 in a state where the lens unit 200 is connected (attached) to the camera body 100 will be described below with reference to FIG. The camera 1 may have a configuration in which the camera body 100 and the lens unit 200 are integrally provided.

  As illustrated in FIG. 1, the camera control unit 101 is a camera control unit that generally controls the operation of the camera 1, and internally includes a camera CPU as a control microprocessor (computer). The camera control unit 101 further includes an internal timer 101a capable of measuring time. The built-in timer 101a is a so-called real-time clock, and measures time in each operation based on information such as an interval such as hour, minute, second of the timer stored in advance in the memory 102 described later and a time zone set at the time of camera initialization. Run. The camera control unit 101 executes various control and processing described later based on a computer control program stored in a memory 102 described later.

  The memory 102 is a recording medium capable of recording data related to the operation of the camera 1 and various data acquired using the camera 1. The memory 102 of this embodiment includes a ROM area as a non-volatile memory and a RAM area as a volatile memory.

  The lens control unit 201 is a lens control unit that generally controls the operation of the lens unit 200, and internally includes a lens CPU as a lens control microprocessor (computer). With the lens unit 200 mounted on the camera body 100, the lens control unit 201 can mutually communicate with the camera body 100 via an interface (IF) shown in FIG. The imaging lens group 202 is a lens group including a plurality of lenses such as a shift lens, a zoom lens, and a focus lens, and forms a light flux corresponding to an optical image of a subject on the image sensor 103 inside the camera body 100. Is an optical member of The diaphragm 203 is a light amount adjusting member for adjusting the light amount corresponding to the light beam incident through the imaging lens group 202.

  The imaging device 103 is an imaging unit that employs a charge storage type solid-state imaging device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging element 103 photoelectrically converts the light flux formed on the imaging surface of the imaging element 103 and outputs analog image data (analog image signal).

  The shutter 104 is a shielding member capable of shielding a light flux incident on the imaging element 103, and can be switched to a retracted state for guiding the incident light flux to the imaging element 103 without shielding the light flux and a shielding state for shielding incident light It is.

  The A / D conversion unit 105 is an A / D conversion unit that converts analog image data output from the imaging element 103 into digital image data. The image processing unit 106 is an image processing unit that performs predetermined image interpolation, resizing processing such as reduction, color conversion processing, and calculation processing of the number of pixel data such as saturated pixels and black-flooded pixels on digital image data. In addition, the image processing unit 106 performs white balance (hereinafter, simply referred to as WB) (comment; for this reason, "WB processing means", "WB coefficient", etc.) appear on digital image data, so WB is white. It should be shown in advance that it is an abbreviation of balance.) It is a WB processing means that performs arithmetic processing. The WB arithmetic processing multiplies the signal value of each color signal (signal of RGB Bayer array) corresponding to the image data output from the imaging element 103 by a predetermined WB coefficient, so that the image data is processed according to various conditions. WB adjustment is possible. Note that the predetermined WB coefficient is a gain amount that is different for each color signal. The WB coefficient is, for example, data stored in advance assuming a predetermined ambient light, data calculated based on a color temperature manually set by the user, or a signal of each color signal from acquired image data The value is set based on data calculated by extracting the value.

  The D / A conversion unit 108 is a D / A conversion unit that converts digital image data into analog image data for display. The memory control unit 107 is a recording control unit that controls input and output of image data to each unit such as the A / D conversion unit 105, the image processing unit 106, and the D / A conversion unit 108. Although the camera 1 according to the present embodiment includes the imaging device 103 as an imaging unit, for example, a configuration including an A / D conversion unit 105, an image processing unit 106, and the like may be used as the imaging unit.

  The timing generator (hereinafter referred to as TG) 110 is timing generation means for emitting a timing signal related to each operation of the camera 1 toward each part of the camera 1. For example, the TG 110 can emit timing signals related to various operations such as charge accumulation in the imaging device 103, change of the frame rate, and change of the state of the shutter 104.

  The display unit 109 is a display unit configured by a TFT type LCD (Thin Film Transistor Drive Type Liquid Crystal Display) or the like, and can display analog image data for display. The display unit 109 can perform so-called live view display (hereinafter, referred to as LV display) in which image data acquired using the imaging element 103 is sequentially displayed. The display unit 109 can display various information other than the acquired image data.

  The release button 111 is an imaging instruction means for a still image which instructs the start of the imaging preparation operation of the still image of the subject and the imaging operation of the still image. Note that the release button 111 may be operated to instruct the start of the imaging operation of a moving image for recording. In the camera 1 according to the present embodiment, the user instructs the start of the imaging preparation operation for a still image by setting the release button 111 to the SW1 state (for example, half depression), and focus control and photometric calculation described later are performed. Ru. In addition, when the user sets the release button 111 to the SW2 state (for example, full press), the start of the still image capturing operation using the shutter 104 is instructed, and the subject is captured to acquire the still image and the moving image A series of processes are performed until the recording is completed.

  The operation unit 112 is an operation unit that inputs various operation instructions according to the user's manual operation to the camera control unit 101. FIG. 2 is a view exemplarily explaining the external view (rear view) of the camera 1 according to the present invention. The broken line portions illustrated in FIG. 2 indicate the first operation unit 112 a and the second operation unit 112 b, respectively. The first operation unit 112 a includes direction instruction buttons for instructing various operations related to imaging and an LV button for instructing execution and termination of LV display on the display unit 109. The second operation unit 112 b includes a power switch and a mode dial for setting an imaging mode. Note that if a capacitive touch panel or the like is adopted as the display unit 109, the display unit 109 may function as an operation unit that can input each operation described above. The display control unit 113 is a display control unit that controls image display on the display unit 109. The display control unit 113 can select image data to be displayed on the display unit 109 or set on / off (display / non-display) of the display unit 109 in accordance with an instruction from the camera control unit 101.

  The focus detection circuit 114 is a focus detection unit that includes a focus sensor (not shown) and detects the in-focus state of the optical image corresponding to the light beam incident from the lens unit 200 side. The focus detection circuit 114 can calculate distance information from the camera 1 to a predetermined subject based on the focus detection result. The detection result of the focus detection circuit 114 is used for control (focus control) of the lens position of a focus lens (not shown) included in the lens unit 200. A light beam incident through the imaging lens group 202 is guided to the image sensor 103 side and the focus sensor side by a mirror (not shown). The camera 1 according to the present embodiment is configured to execute focus control based on the output of the focus detection circuit 114 using a phase difference detection method, but is configured to use a contrast detection method based on contrast information of image data. It may be. Further, although the camera 1 of the present embodiment is configured to include a focus sensor separate from the imaging element 103, data output from pixels that can be detected by focus included in the imaging element 103 without including a focus sensor The focus detection may be performed based on

  The photometric circuit 115 is a photometric unit that includes a photometric sensor (not shown) and calculates a photometric value corresponding to a light beam incident from the lens unit 200 side. The photometry result of the photometry circuit 115 is output to the camera control unit 101 and used for exposure control. The calculation method of the luminance value will be specifically described. First, the acquired image data is divided into a plurality of blocks, and the average luminance value of each block is calculated. Then, the average luminance value of each block is integrated to obtain a representative luminance value. In the following description, this representative luminance value is used as a photometric value of an object for various processing and control such as exposure control. In the present embodiment, the photometric operation is performed using a photometric sensor, but the photometric operation may be performed based on the output of the image sensor 103.

  The target value setting unit 116 is a target value setting unit that sets target values for exposure control and WB adjustment based on the photometry result of the subject. That is, when acquiring an image using the imaging element 103, the target value setting unit 116 is a target value related to the brightness of the image, and is a target for changing the brightness in a predetermined number of frames. Is a means to set the following value. In the present embodiment, at the time of acquisition of moving images for recording and LV display, the photometry circuit 115 measures a subject for each predetermined number of frames to calculate a photometric value. The target value setting unit 116 sets a target value for exposure and a target value for WB adjustment based on the photometric value.

  Note that if the amount of exposure or WB adjustment is changed sharply toward the target value when acquiring a moving image, the brightness may change frequently between the frames constituting the moving image, which may cause the user to feel uncomfortable. . Therefore, a configuration may be provided in which a predetermined amount of hysteresis (dead zone) is provided with respect to the target value set by the target value setting unit 116, and the exposure and WB are not changed within the range of the hysteresis. In this case, the actual exposure (referred to as a controlled exposure) is changed toward the target exposure when a change in luminance of a predetermined amount or more occurs with reference to the set exposure.

  The motion detection unit 117 is a motion detection unit that detects, for example, an attitude change or a motion amount (such as an angular velocity and an acceleration) of the camera 1 based on an output result of a gyro sensor (not shown). The camera control unit 101 or the like compares the plurality of images output from the imaging element 103 to calculate the motion vector of the subject, and detects the motion vector as the posture change or motion amount of the camera 1. It is also good.

  The external recording medium 300 is a recording medium such as a memory card or a hard disk that can be attached to and detached from the camera body 100. For example, the external recording medium 300 can record an image obtained by imaging a subject. In addition, although the external recording medium 300 of this embodiment employ | adopts the memory card which can be inserted in and removed from the camera main body 100, it is not limited to this, Optical disks, such as a DVD-RW disk, Magnetic disks, such as a hard disk It may be The above is the basic configuration of the camera of the present embodiment.

(Imaging mode)
Hereinafter, an imaging mode that can be set by the camera 1 will be described. The camera 1 according to the present embodiment can set a normal still image mode, a normal moving image mode, and a time lapse mode as an imaging mode.

  The normal still image mode is an imaging mode for acquiring single image data (still image) for recording. The normal moving image mode is an imaging mode in which image data (moving image) is acquired based on a plurality of image data groups continuously acquired using the imaging device 103. The time-lapse mode is an imaging mode for generating image data (time-lapse moving image) in which a plurality of pieces of image data acquired by performing intermittent imaging at intervals longer than the moving image mode of the subject are acquired in acquisition order. .

  In the present embodiment, when the time lapse mode is set, the time-lapse moving image is generated (combined) in the imaging device, but the present invention is not limited to this. For example, the time lapse mode may be at least an imaging mode for performing intermittent imaging for a time-lapse moving image in the imaging device, and generation (synthesis) of the time-lapse moving image is performed by a signal processing device or the like outside the imaging device. It may be a configuration.

  In the normal moving image mode and the time lapse mode, the reproduction time of the acquired moving image and the total imaging time for acquiring the moving image (period required from the start of the first imaging to the end of the last imaging) The relative relationship is different. Specifically, in the normal moving image mode, the total imaging time for acquiring a single moving image and the reproduction time of the moving image are substantially the same. On the other hand, in the time-lapse mode, the reproduction time of the time-lapse video is shorter than the total imaging time for acquiring a single time-lapse video. Therefore, in the time-lapse moving image acquired in the time-lapse mode, temporal change of the subject can be compressed.

  In the time lapse mode, the imaging interval of the interval imaging is preset, and predetermined imaging such as 1 second, 30 seconds, 1 minute, 15 minutes, 30 minutes, 1 hour, 3 hours, 5 hours, 10 hours, 24 hours, etc. The user can set an arbitrary imaging interval from the interval (time interval). Also, the user may be able to freely set an arbitrary imaging interval. For example, the imaging interval may be longer than 24 hours, or the imaging interval may be shorter than 1 second.

  Further, in the time lapse mode, it is possible to set a total imaging time (or a total number of imaging times) from the start to the end of the plurality of intermittent imaging operations. Furthermore, in the time lapse mode, intermittent imaging can be performed indefinitely as long as power supply from a power source (not shown) such as a battery provided in the camera 1 continues regardless of the total imaging time or the total number of imagings. . Each imaging mode described above can be freely set by the user operating the operation unit 112.

  In the time-lapse mode, the camera 1 of the present embodiment performs interval shooting based on the imaging interval set in advance by the user, and generates still-moving images by joining still images acquired intermittently. is there. On the other hand, a configuration is used in which a moving image is acquired using the imaging element 103, and an image used to generate a time-lapse moving image is intermittently extracted from images constituting the moving image according to a preset imaging interval. It may be When this configuration is employed, the number of charge accumulation lines of the image sensor 103 at the time of imaging a subject is reduced (the charge accumulation is performed by thinning pixel lines) as compared to the case of acquiring a still image intermittently. The processing load on the camera 1 when capturing an object can be reduced.

(Imaging process in time-lapse mode)
Hereinafter, the imaging process in the time lapse mode will be described with reference to FIG. FIG. 3 is a flow chart for explaining an imaging process in the time lapse mode according to the present invention. When the imaging mode is set to the time lapse mode, in step S301, the camera control unit 101 initializes the value of the number of exposure smoothed frames N_EVave, which indicates the degree of smoothing of the exposure when shooting an object, to zero. Details of the smoothing of the exposure will be described later.

  Next, in step S302, the camera control unit 101 determines whether acquisition of a time-lapse moving image has been instructed. In the camera 1 according to the present embodiment, for example, in response to the operation of the operation unit 112 by the user, an instruction to start acquisition of an image (referred to as a time-lapse image) used to generate a time-lapse video (shooting of an object) is instructed It is determined whether or not it is. In other words, in the process of step S302, it is determined whether acquisition of an image corresponding to the first frame in a single time lapse moving image has been instructed.

  When an instruction to acquire a time-lapse moving image is given, the process proceeds to step S303, and the camera control unit 101 secures a photometric value holding area EVHist that holds a photometric value acquired by photometry of a subject described later. In the present embodiment, the light metering holding area EVHist is developed in the memory 102.

  Next, in step S304, the camera control unit 101 monitors the acquisition timing of the time-lapse image (the imaging timing of the subject) based on the count of the built-in timer 101a. Note that the intermittent imaging of the subject related to the generation of the time-lapse moving image is performed based on the fact that the time measurement from the previous imaging has reached the imaging interval based on the imaging interval set in advance. Here, in the first imaging among the intermittent imaging relating to acquisition of a single time-lapse moving image, an object may be imaged without being counted by the built-in timer 101a in accordance with the acquisition instruction of the time-lapse moving image by the user I see. Alternatively, an arbitrary time interval for the first imaging may be set, and after the acquisition instruction of the time-lapse moving image, the subject may be imaged according to the time measurement of the built-in timer 101a reaching the time interval. The process of step S304 is repeated until the imaging timing is reached.

  In response to the imaging timing being reached, the photometric circuit 115 calculates the photometric value of the subject in step S305. The photometric calculation method is as described above. Then, when the photometric calculation is completed, the process proceeds to step S306, and the camera control unit 101 stores the calculated latest photometric value in the photometric value holding area EVHist secured earlier.

  Next, in step S307, the camera control unit 101 executes exposure smoothing degree determination processing for smoothing the exposure when capturing an object. Generally, time-lapse video has a longer time interval when acquiring a plurality of images constituting the video as compared with a normal video. Therefore, when the exposure at the time of imaging is made to follow the change in the brightness of the subject as when acquiring a normal moving image, the degree of change in the brightness of the subject between the images constituting the time-lapse moving image becomes steep. I will. In the time-lapse moving image acquired in this case, an unnatural flicker occurs in the moving image due to a sudden change in the brightness of the subject.

  With respect to this problem, when acquiring time-lapse moving images, it is possible to suppress the effect of flickering by applying a technique for smoothing the exposure at the time of imaging between intermittent imaging relating to generation of time-lapse moving images. . Specifically, in each intermittent imaging, the brightness between the images is obtained by smoothing the exposure used in the past imaging relating to the generation of a single time-lapse movie and the exposure indicating the brightness of the current subject. It is possible to generate a time-lapse video in which the change of is smooth.

  However, when the smoothing of the exposure is uniformly performed without considering the information related to the acquisition of the time-lapse moving image, the time-lapse moving image with the brightness not intended by the user may be acquired. For example, in the case of imaging a landscape with an imaging interval of 1 minute, when the degree of exposure smoothing is low, flickers in time-lapse video become noticeable due to temporary changes in external light (for example, passing of a car at night). Conversely, when capturing a landscape with an imaging interval of 5 hours, if the exposure smoothing degree is high, the brightness of the subject in the time-lapse video is affected by the exposure used at the time of past imaging, even if the ambient light changes significantly Unnaturally dark or bright. The former assumes that the change in ambient light (external light) is small based on the imaging interval of intermittent imaging as information on the acquisition of time-lapse video, and the exposure change between each image constituting the video is as smooth as possible You should give priority to the quality of time-lapse videos so that In the latter, assuming that the change in ambient light is large, the quality of the time-lapse moving image should be prioritized so that the exposure of the subject is as appropriate as possible for each imaging.

  Therefore, in the present embodiment, by controlling the degree of smoothing of the exposure based on the imaging interval of intermittent imaging as information related to the acquisition of the time-lapse video, the quality of the time-lapse video is maintained, and the brightness change of the subject in the time-lapse video Suppress unnatural changes.

  Hereinafter, the details will be described with reference to FIG. FIG. 4 is a flowchart showing exposure smoothing degree determination processing <A> in step S307 of FIG. 3 according to the first embodiment of the present invention, and exposure is performed based on a preset imaging interval (Interval). It is a figure explaining the case where the number N_EVave of smoothing frames is determined. In the present embodiment, the number of exposure smoothed frames refers to the past imaging that refers to the photometric value (or exposure) when determining the target exposure corresponding to each imaging for acquiring the time-lapse image in the time-lapse mode. Points to the number.

  As illustrated in FIG. 4, in step S401, the camera control unit 101 reads a preset imaging interval (Interval), and determines whether the imaging interval is longer than 24 hours in step S402. If it is determined by the camera control unit 101 that the imaging interval is longer than 24 hours (YES in step S402), the process proceeds to step S403, 24 hours is subtracted from the current imaging interval, and the process returns to step S402. If the camera control unit 101 determines that the imaging interval is 24 hours or less by repeating the processes of steps S402 to S403, the process proceeds to step S404. In the processing of steps S402 to S403, assuming that the brightness of ambient light every 24 hours is substantially the same, the actual change degree of ambient light is obtained by subtracting the Interval value from the actual imaging interval in units of 24 hours. Is a flow to determine

  Next, in step S404, the camera control unit 101 determines whether the imaging interval is longer than 12 hours. If the camera control unit 101 determines that the imaging interval is longer than 12 hours (YES in step S404), the process advances to step S405, and the camera control unit 101 sets the number of exposure smoothed frames to N_EVave = 3. If the camera control unit 101 determines that the imaging interval is 12 hours or less (NO in step S404), the process advances to step S406.

  Next, in step S406, the camera control unit 101 determines whether the imaging interval is longer than 3 hours. If it is determined by the camera control unit 101 that the imaging interval is longer than 3 hours (YES in step S406), the process advances to step S407, and the camera control unit 101 sets the number of exposure smoothed frames N_EVave = 5. If the camera control unit 101 determines that the imaging interval is 3 hours or less (NO in step S406), the process advances to step S408, and the camera control unit 101 sets the number of exposure smoothed frames to N_EVave = 10. The above is the exposure smoothing degree determination process according to the present embodiment.

  The exposure smoothed frame number N_EVave set in accordance with the flow of FIG. 4 indicates the number of exposures at the time of imaging in the past (related to the image used to generate a single time-lapse movie) to be referred to when setting the target exposure. There is. Then, as the number of exposure smoothed frames increases, the degree of reference to exposure in past imaging increases, so the degree of smoothed exposure becomes stronger (larger), and as the number of exposed smoothed frames decreases, the degree of smoothed exposure becomes larger. Weak (small).

  Returning to FIG. 3, when the number of exposure smoothed frames is set in the process of step S307, the target value setting unit 116 executes an exposure calculation process in step S308. The details will be described with reference to FIG. FIG. 5 is a flowchart showing exposure calculation processing according to the present invention.

  As illustrated in FIG. 5, in step S501, the target value setting unit 116 sets the number of time-lapse images already acquired as the image used for generating a single time-lapse moving image (the number of imaging) to the number of exposed smoothed frames. It is determined whether it is smaller than N_EVave.

  If it is determined by the target value setting unit 116 that the number of time-lapse images is smaller than the number of exposure smoothed frames (YES in step S501), the target value setting unit 116 in step S502 acquires N_calc as the time-lapse image acquired so far Set to number. If the target value setting unit 116 determines that the number of time-lapse images is equal to or greater than the exposure smoothed frame number (NO in step S501), the target value setting unit 116 calculates the N_calc in step S503. Set to the number of frames N_EVave. Here, N_calc indicates the number of recorded photometric values to be actually referred to when calculating the target exposure corresponding to the next imaging.

Next, in step S504, the target value setting unit 116 refers to the photometric values for the N_calc number from the EVHist area of the memory 102 holding the photometric values at the time of the past imaging, Determine the control photometric value when acquiring an image. When N_calc = 5 is set, assuming that the photometric values recorded in the respective EVHist areas are EVHist [n], the calculation of the control photometric value Bv is as shown in the following equation (1) To
Bv = {EVHist [n-4] + EVHist [n-3] + EVHist [n-2] + EVHist [n-1] + EVHist [n]} / N_calc (1)
Calculated based on Here, n is a natural number including 0. Then, the target exposure is calculated by converting the calculated control photometric value into an exposure.

  As described above, the case where N_calc = 5 is set will be exemplarily described with reference to FIG. FIG. 6 is a view exemplarily explaining the smoothed exposure in the time lapse mode according to the present invention. FIG. 6A exemplarily illustrates the relationship between the photometric value recorded in the EVHist area according to the present invention and the actual target exposure. FIG. 6B is a view for explaining an example of the relationship between a plurality of photometric values recorded in the EVHist area according to the present invention and an actual target exposure.

  As illustrated in FIG. 6, an EVHist area [n] indicating a photometric value corresponding to the present imaging is set as EVHist [4]. In this case, the average value of the photometric values EVHist [0] to [4] at the time of acquiring the five time-lapse images including the photometric value and the photometric value corresponding to the imaging before this imaging corresponds to the target exposure. Do. In the example illustrated in FIG. 6, the value of the target exposure corresponding to the timing is relative to the actual brightness of the subject at the timing when EVHist [4] is acquired in view of the transition of the photometric value at the time of imaging in the past. Lower.

  FIG. 7 is a view exemplarily explaining the relationship between the difference in the number of exposure smoothed frames and the transition of the target exposure according to the present invention, in which the vertical axis represents the passage of time and the horizontal axis represents the magnitude of the luminance value. It represents. As illustrated in FIG. 7, as the number of exposure smoothed frames increases, the control photometric value gradually transitions with respect to the actual photometric value at each timing, so that the change in the target exposure becomes gentler. On the other hand, as the number of smoothed exposure smoothed frames decreases, the control photometric value transitions sharply with respect to the actual photometric value at each timing, so that the change in the target exposure becomes steeper, and the brightness of the subject at each timing Appropriate exposure is set.

  Returning to FIG. 3, when the target exposure is determined in step S308, the camera control unit 101 controls the respective units of the camera 1 in step S309 to change the exposure at the time of imaging so as to become the previously determined target exposure. . Then, in step S310, the camera control unit 101 controls each unit of the camera 1 to capture an object, and acquires a time-lapse image.

  After obtaining the time-lapse image, the camera control unit 101 determines an instruction to end intermittent imaging in step S311. In the present embodiment, the camera control unit 101 determines that an instruction to end intermittent imaging has been issued when the preset total number of imaging times has been reached. In addition to this, for example, it is also configured to detect whether or not an end instruction has been given by the user before reaching the total number of times of imaging, and to determine whether or not to end intermittent imaging according to the presence or absence of the instruction. Good.

  If it is determined that the camera control unit 101 instructs the end of imaging (YES in step S311), the camera control unit 101 connects the acquired time-lapse images in the order of acquisition to generate time-lapse moving images in step S312. The imaging process ends. If it is determined that the camera control unit 101 has not instructed the end of imaging (NO in step S311), the process returns to step S304 to repeat the above-described processes. The above is the imaging process in the time lapse mode according to the present embodiment.

  In the present embodiment, the exposure smoothing in the time lapse mode is configured to refer to the photometric value at the time of imaging in the past, but may be configured to refer to the exposure at the time of imaging in the past. In this case, the information on the target exposure obtained in step S308 is recorded in the EVHist area in association with the information on the imaging order corresponding to the acquired time lapse image, and the photometric value calculated in step S305 is converted to an exposure (for example, , APEX unit) and execute exposure calculation processing.

  As described above, according to the camera 1 of the present embodiment, the degree of smoothing of the exposure is made variable based on the imaging interval as the information related to the acquisition of the time-lapse moving image. More specifically, the camera 1 according to the present embodiment relates to acquisition of the time-lapse image in the case of acquiring the time-lapse image at the second interval at which the imaging interval is shorter than the first interval at which the imaging interval is long. It is the structure which enlarges the smoothing degree of the exposure at the time of imaging. With this configuration, the camera 1 according to the present embodiment can suppress unnatural flickering in the time-lapse moving image, and can suppress that the time-lapse image has unnatural brightness with respect to a change in luminance of the subject.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes are possible within the scope of the present invention. For example, in the above-described embodiment, the imaging interval is referred to as the information related to the acquisition of the time-lapse moving image in the exposure smoothing number determination process, but the number of exposure smoothing frames is determined based on other information. It may be.

  As the second embodiment, a configuration for determining the number of exposure smoothed frames based on the frame rate of the time-lapse moving image to be acquired as information on acquiring the time-lapse moving image will be described with reference to FIG. FIG. 8 is a flowchart showing exposure smoothing degree determination processing <B> according to the second embodiment of the present invention, in which the number of exposure smoothed frames N_EVave is determined based on the frame rate of the time-lapse moving image. It is a figure explaining.

  Generally, the higher the frame rate of a moving image, the shorter the display interval of the images, and therefore the flicker due to the difference in brightness between the images is also noticeable. Therefore, in the second embodiment of the present invention, the higher the frame rate of the time-lapse moving image to be acquired, the stronger (larger) the exposure smoothing degree, and the lower the frame rate, the weaker (smaller) the exposure smoothing degree. Details of this will be described below.

  As illustrated in FIG. 8, in step S801, the camera control unit 101 detects a frame rate (FrameRate) of the time-lapse moving image to be acquired. If the user can set the frame rate of the time-lapse video, the user detects a frame rate set in advance. Also, when the user can set the video method (for example, NTSC or PAL), the frame rate corresponding to the video method set by the user is detected.

  Next, in step S802, the camera control unit 101 determines whether the previously detected frame rate is higher than 60 fps. If the camera control unit 101 determines that the frame rate is higher than 60 fps, the camera control unit 101 sets the number of exposure smoothed frames to N_EVave = 10 in step S803. If the camera control unit 101 determines that the frame rate is 60 fps or less, the process advances to step S804.

  Next, in step S804, the camera control unit 101 determines whether the previously detected frame rate is higher than 30 fps. If the camera control unit 101 determines that the frame rate is higher than 30 fps, the camera control unit 101 sets the number of exposure smoothed frames to N_EVave = 5 in step S805. If the camera control unit 101 determines that the frame rate is 30 fps or less, the camera control unit 101 sets the number of exposure smoothed frames to N_EVave = 3 in step S806.

  Further, as a third embodiment, a configuration for determining the number of exposure smoothed frames based on the amount of movement of the camera 1 as information regarding acquisition of time-lapse moving images will be described with reference to FIG. FIG. 9 is a flowchart showing exposure smoothing degree determination processing <C> according to the third embodiment of the present invention, in which the number of exposure smoothed frames N_EVave is determined based on the amount of movement of the imaging device. It is a figure explaining.

  Note that although the processing of FIG. 9 is executed following the exposure smoothing degree determination processing <A> and <B> described in FIG. 4 and / or FIG. 8 described above, the exposure shown in FIG. Only the smoothing degree determination process may be executed. As illustrated in FIG. 9, in step S 901, the camera control unit 101 determines whether or not a motion (blur) equal to or more than a predetermined amount occurs in the camera 1 based on the detection result of the motion detection unit 117. If it is determined by the camera control unit 101 that a motion of a predetermined amount or more has occurred in the camera 1 (YES in step S901), the camera control unit 101 sets the number of exposure smoothed frames N_EVave = 0 in step S902. If it is determined by the camera control unit 101 that the camera 1 has not moved by more than a predetermined amount (NO in step S901), the exposure previously determined according to the flow of FIG. 4 and / or FIG. The process ends without changing the number of smoothed frames.

  In so-called walk-laps shooting in which the user carries out interval shooting while carrying the imaging apparatus, the change in the subject (change in composition) is more noticeable than the change in exposure in the moving image generated based on the interval shooting. Therefore, at the time of the walk-lapse shooting, it is possible to more effectively record the change of the subject by performing the exposure control so that the degree of smoothing of the exposure is reduced and the appropriate exposure is approached for each shooting. Therefore, in the third embodiment illustrated in FIG. 9, when the camera 1 has a motion of a predetermined amount or more, it is determined that the walk-lapse shooting is performed, and the number of exposure smoothed frames is set to zero.

  Note that the number of exposure smoothing frames set in this case may be a value other than 0, in which case the number of exposure smoothing frames is smaller than the lower limit value that can be set by the processing shown in FIGS. 4 and 8. Preferably it is a number.

  Further, when the walk-up mode can be set as one of the imaging modes of the camera 1, it is not the configuration for detecting the movement amount of the camera 1 but the configuration for detecting whether or not the walk-up mode is set. May be In this case, when the camera control unit 101 detects that the walk-up mode is set, the process proceeds to the process of step S902 described above.

  Note that the processing of the exposure smoothing degree determination processing <A> to <C> described above may be configured to connect and execute each processing. For example, the exposure smoothing degree determination process <B> may be performed after the exposure smoothing degree determination process <A>. In this case, any one of the exposure smoothing frame number determined in the exposure smoothing degree determination process <A> or the exposure smoothing degree determination process <B> may be given priority, or each process The number of exposure smoothed frames may be determined based on the result of. For example, when the imaging interval is between 3 and 12 hours and the frame rate of the time-lapse moving image is 60 fps, the number of exposure smoothed frames N_EVave may be set to 7.

  In the above-described embodiment, the time-lapse moving image is generated inside the camera 1 in the time-lapse mode, but the invention is not limited to this. That is, the camera 1 may be configured to perform intermittent imaging (interval shooting) for acquiring a recorded image used to generate a time-lapse moving image, and generate the time-lapse moving image on an external device or a computer network.

  In the embodiment described above, the camera control unit 101, the memory 102, the memory control unit 107, the photometry circuit 115, the target value setting unit 116, etc. operate in cooperation with one another to control the operation of the camera 1. Although it was, it is not limited to this. For example, a computer program according to the flow illustrated in FIGS. 3 to 5 and 8 to 9 described above is stored in advance in the memory 102, and the computer program is executed by the camera control unit 101 or the like. It may be configured to control the operation.

  Further, as long as it has the function of a program, the form of the program may be any one, such as an object code, a program executed by an interpreter, script data supplied to an OS, and the like. The recording medium for supplying the program may be, for example, a hard recording medium, a magnetic recording medium such as a magnetic tape, or an optical / optical magnetic recording medium.

  Moreover, although the case where a digital camera was employ | adopted as an example of the imaging device which implements this invention was demonstrated in embodiment mentioned above, it is not limited to this. For example, a configuration may be adopted in which an imaging device other than a digital camera such as a portable device such as a digital video camera or a smartphone, a security camera, or the like is adopted.

(Other embodiments)
Furthermore, the present invention provides a program that implements the functions of the above-described embodiments to a system or apparatus via a network or storage medium, and one or more processors in the computer of the system or apparatus read and execute the program. But it can be realized. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

Reference Signs List 1 digital camera 100 camera main body 101 camera control unit 102 memory 103 imaging device 115 photometry circuit 116 target value setting unit 200 lens unit 300 external recording medium

Claims (10)

An imaging apparatus capable of setting a mode for performing intermittent imaging using an imaging unit, comprising:
Photometry means for measuring the subject,
A setting unit configured to set information on exposure corresponding to each of intermittent imaging based on the photometric result of the photometric unit in the mode;
A detection unit that detects, in the mode, first information related to acquisition of a moving image obtained by joining a plurality of images acquired by intermittent imaging;
Have
The setting means sets information on the exposure by controlling a smoothing degree of exposure between successive imagings in intermittent imaging based on the first information detected by the detection means. Imaging device. The detection means detects, in the mode, information on an imaging interval of intermittent imaging as the first information;
The setting means is based on the first information detected by the detection means, and the imaging interval is more than the first interval than when the continuous imaging interval in intermittent imaging is the first interval. The imaging apparatus according to claim 1, wherein control is performed such that the degree of smoothing of the exposure is larger when the second interval is shorter. The detection means detects, in the mode, information on a frame rate of the moving image as the first information;
The setting means may be configured to set a second frame rate lower than the first rate based on the first information detected by the detection means than when the frame rate of the moving image is the first rate. The imaging apparatus according to claim 1, wherein control is performed such that the degree of smoothing of the exposure is smaller in the case of rate. The detection means detects, in the mode, information related to the movement of the imaging device as the first information;
When the movement of the imaging device is equal to or more than a predetermined amount based on the first information detected by the detection means, the setting unit is more than the case where the movement of the imaging device is smaller than a predetermined amount. The imaging apparatus according to any one of claims 1 to 3, wherein control is performed such that the degree of smoothing of the exposure is reduced.   The setting means includes a plurality of photometry results of the photometry means corresponding to current imaging in intermittent imaging, and photometry results of the photometry means corresponding to imaging prior to current imaging in intermittent imaging. Setting the information related to the exposure based on the average value of the photometry results, and controlling the smoothing degree of the exposure by making the number of the plurality of photometry results used for calculating the average value variable. The imaging device according to any one of claims 1 to 4.   The setting means is based on an average value of a plurality of exposures including an exposure corresponding to current imaging in intermittent imaging and an exposure corresponding to previous imaging in intermittent imaging. The smoothing degree of the said exposure is controlled by setting the information regarding A, making variable the number of several exposures used for calculation of the said average value, It is described in any one of the Claims 1 thru | or 4 characterized by the above-mentioned. Imaging device.   The imaging apparatus according to any one of claims 1 to 6, wherein the mode is a mode in which intermittent imaging for acquiring a plurality of images used for generating a time-lapse moving image is performed. A control method of an image pickup apparatus capable of setting a mode for performing intermittent image pickup using an image pickup means, comprising:
A setting step of setting information on exposure corresponding to each of intermittent imaging in the mode;
A detection step of detecting first information related to acquisition of a moving image obtained by joining a plurality of images acquired by intermittent imaging in the mode;
Have
In the setting step, based on the first information detected in the detection step, information on the exposure is set by controlling a smoothing degree of exposure between successive imaging in intermittent imaging. The control method of the imaging device characterized.   A computer readable program for causing a computer to execute the method of controlling an imaging device according to claim 8.   A computer readable recording medium having the program of claim 9 recorded thereon.

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