JP2019197185A - Imaging device, control method, and program - Google Patents

Abstract

To make it possible, in a panning shot involving a change in focal distance due to zooming, to easily obtain an image including a suitable panning effect.SOLUTION: An imaging device 1 comprises: imaging means 112 that picks up a subject image incident via an imaging optical system 102; detection means 109 that detects the amount of temporal change in focal distance of the imaging optical system 102; angular velocity calculation means 118 that calculates an angular velocity corresponding to the amount of movement of a subject; and exposure time control means 119 that determines an exposure time. In a panning shot imaging mode, the exposure time control means 119 determines the exposure time on the basis of the amount of temporal change in focal distance detected by the detection means 109 and the angular velocity of the subject calculated by the angular velocity calculation means 118.SELECTED DRAWING: Figure 1

Description

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

  An imaging method using an imaging device such as a camera is based on panning. Panning is a technique for capturing an image while the direction of the imaging device follows the movement of a subject moving in the horizontal direction, for example. Conventionally, in an imaging apparatus, a function for assisting panning is proposed. For example, Patent Document 1 discloses a technique for determining whether or not the currently performed imaging is in the panning state and changing the exposure control according to the determination result.

JP2015-154409A

  Incidentally, some imaging methods using an imaging apparatus perform panning while zooming. In this case, in the captured image, a background flow due to zooming occurs in addition to a background flow due to panning, and an excessive background flow that cannot occur with simple panning can occur. For this reason, for example, even if the technique of Patent Document 1 is adopted, it is not easy for the user to obtain a desired sink effect by zoom panning. In zoom panning, the user operates the orientation and zooming of the imaging device so as to maintain the angle of view of the subject. In order to obtain a desired flow effect, the user must predict the operation contents in advance and set an appropriate exposure time based on the prediction in the imaging apparatus in advance. In order to be able to do this work properly, the user needs a lot of experience. As described above, an imaging apparatus is required to easily obtain an image including a suitable sink effect in panning with a change in focal length due to zoom or the like.

  An imaging apparatus according to the present invention corresponds to an imaging unit that captures an image of a subject incident through an imaging optical system, a detection unit that detects a temporal change amount of a focal length of the imaging optical system, and an amount of movement of the subject. An angular velocity calculation means for calculating an angular velocity; and an exposure time control means for determining an exposure time, wherein the exposure time control means includes a temporal change amount of the focal length detected by the detection means in a panning imaging mode. The exposure time is determined based on the angular velocity of the subject calculated by the angular velocity calculating means.

  According to the present invention, it is possible to easily obtain an image including a suitable sink effect in sink imaging with a change in focal length due to zoom or the like.

1 is a schematic configuration diagram of an imaging apparatus according to an embodiment of the present invention. It is a figure explaining the change of the positional relationship of the to-be-photographed object and background in the normal panning as a comparative example. It is explanatory drawing of the captured image in each position of FIG. 2 of a comparative example. It is a figure explaining the change of the positional relationship of the to-be-photographed object and background in zoom panning. It is explanatory drawing of the captured image in each position of FIG. It is a flowchart which shows the example of the calculation process of the shutter speed for a panning assist in this embodiment. It is a figure explaining the positional relationship of the to-be-photographed object and the background in zoom panning. It is a figure explaining how the background flows in the captured image by zoom panning.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the configurations described in the following embodiments are merely examples, and the scope of the present invention is not limited by the configurations described in the embodiments.

  FIG. 1 is a schematic configuration diagram of an imaging apparatus 1 according to an embodiment of the present invention. Examples of the imaging apparatus 1 include a lens-exchangeable digital camera, a lens-integrated digital camera (compact digital camera), a video camera, and a surveillance camera. An imaging apparatus 1 shown in FIG. 1 is an interchangeable lens digital camera, and includes an interchangeable lens 100 and a camera body 127. The interchangeable lens 100 is a lens device that can be attached to and detached from the camera body 127. Note that the imaging apparatus 1 may be one in which the lens cannot be replaced. The interchangeable lens 100 includes an imaging lens unit 101. The imaging lens unit 101 includes a zoom lens group (hereinafter, referred to as “zoom lens”) 102 that is an imaging optical system, and a focus lens group (hereinafter, referred to as “focus lens”) that forms a subject image. And description) 103. The zoom lens driving unit 104 is interlocked with a zoom ring (not shown) of the interchangeable lens 100. The zoom lens driving unit 104 changes the position of the zoom lens 102 when the user rotates the zoom ring. As a result, the optical magnification of the subject image changes. The interchangeable lens 100 can be zoomed. The focus lens driving unit 105 includes an actuator similar to that of the zoom lens driving unit 104, and moves the position of the focus lens 103. As a result, the focus of the subject changes. In addition, the interchangeable lens 100 includes an encoder 106 that detects the position of the zoom lens 102, and a lens system control microcomputer (hereinafter referred to as “lens microcomputer”) 107. The lens microcomputer 107 has a CPU and a memory, and the CPU executes a program recorded in the memory. As a result, the lens microcomputer 107 implements the lens control means 108 and the zooming detection means 109. The lens control unit 108 transmits to the focus lens driving unit 105 and controls the driving amount necessary for the moving amount and moving speed of the focus lens 103. A zooming detection unit 109 detects position information of the zoom lens 102 obtained from the encoder 106. The zooming detection means 109 can detect the temporal change amount of the focal length of the interchangeable lens 100 based on the position information of the zoom lens 102. In addition, the interchangeable lens 100 includes a lens mount 110 for connecting to the camera body 127. The lens mount 110 is connected to the main body mount 122 of the camera main body 127 in a state where the interchangeable lens 100 is attached to the camera main body 127. The lens microcomputer 107 performs bidirectional serial communication with a camera microcomputer 116 (described later) of the camera body 127 through the lens mount 110 and the body mount 122 at a predetermined timing. For example, the lens mount 110 transmits the position information of the zoom lens 102 detected by the zooming detection unit 109 to the camera microcomputer 116 of the camera body 127.

  The camera main body 127 includes a shutter unit 111, an imaging element 112 such as a CMOS sensor as an imaging unit that captures an image of a subject incident through an imaging optical system, an analog signal processing circuit (AFE) 113, and a camera signal processing circuit 114. Prepare. The camera body 127 also includes a timing generator (TG) 115 that sets the operation timing of the image sensor 112 and the analog signal processing circuit 113. The camera body 127 includes an operation switch 126 such as a power switch and a release switch. In addition, the operation switch 126 may include, for example, a main SW that instructs the camera main body 127 to supply power, and a mode dial in which the user sets the imaging mode. The camera body 127 includes a camera system control microcomputer (hereinafter referred to as “camera microcomputer”) 116 for controlling the entire camera system, a driver 120 for driving a motor for performing a shutter operation, and a shutter driving motor. 121. The camera body 127 includes an angular velocity sensor 123 that outputs angular velocity data of the camera body 127. The camera body 127 includes a memory card 124 for recording captured images, a liquid crystal panel (hereinafter referred to as “LCD”) 125 for monitoring images captured by the camera and displaying the captured images, the interchangeable lens 100, and the like. A main body mount 122 which is a contact portion.

  The camera microcomputer 116 has a CPU and a memory, and the CPU executes a program recorded in the memory. As a result, the camera microcomputer 116 implements background flow amount setting means 117, angular velocity calculation means 118, and exposure time control means 119 as imaging parameter calculation means. The angular velocity calculation means 118 calculates the angular velocity of the main subject corresponding to the amount of movement of the subject in the image. The background sink amount setting unit 117 sets a background sink amount in zoom panning based on a user input. The background flow amount setting means 117 sets, for example, the flow amount for the background of the area in front of the moving direction of the main subject. The exposure time control means 119 determines the exposure time for zoom panning. As will be described in detail later, the exposure time control unit 119 determines the exposure time for zoom panning using the set amount of background flow together with the temporal change amount of the focal length and the angular velocity of the subject. When the operation switch 126 is operated to turn on the power of the imaging apparatus 1, the camera microcomputer 116 detects a change in the state of the operation switch 126 and starts up. The activated camera microcomputer 116 permits power supply to each circuit of the camera body 127 and executes initial setting for each circuit. Further, when power is supplied to the interchangeable lens 100, the lens microcomputer 107 is activated, and initial setting of each part in the interchangeable lens 100 is performed under the control of the lens microcomputer 107. The activated lens microcomputer 107 and the activated camera microcomputer 116 start communication at a predetermined timing. With this communication, at a necessary timing, for example, the camera state, imaging settings, and the like are transmitted from the camera to the lens. Further, the focal length information of the lens is transmitted from the lens to the camera.

  Next, zoom panning will be described. Here, for comparison, first, normal panning without zooming during exposure will be described. FIG. 2 is a diagram for explaining a change in the positional relationship between the subject and the background from the start of exposure to the end of exposure in normal panning as a comparative example. FIG. 2A shows the start of exposure, FIG. 2B shows a temporary point from the start of exposure to the end of exposure, and FIG. 2C shows the end of exposure. FIG. 2A to FIG. 2C are examples in which the panning is performed so that the moving bodies 501a, 501c, and 501e that are subjects that progress in the right front direction toward the user are captured at the center of the angle of view. At the start of exposure in FIG. 2A, the reflected light of the moving body 501a is collected by the condenser lens 504 of the camera device 503 and forms an image at the center of the virtual imaging surface 505. On the virtual imaging surface 505, a stationary body image 502b of the background stationary body 502a located within the range of the imaging field angle 507 is formed. Then, in FIG. 2B, the moving body that advances toward the right front with respect to the user moves to the position of the moving body 501c. The user pans the camera device 503 so that the moving body 501c is captured at the center position 501d of the angle of view. As a result, the background stationary body 502a during normal panning exposure is formed at a position of a stationary body image 502c different from the stationary body image 502b. Furthermore, in FIG.2 (c), the mobile body which progresses further toward the front right with respect to a user moves to the position of the mobile body 501e. The user further pans the camera device 503 so as to capture the moving body 501e at the center position 501f of the angle of view. As a result, the background stationary body 502a during normal panning exposure is formed at a position of a stationary body image 502d different from the stationary body image 502b. Thus, the moving body continues to form an image at the center position of the angle of view during the exposure period. Further, the stationary body image moves from the position of the stationary body 502a to the position of the stationary body image 502d via the position of the stationary body image 502c. On the virtual imaging surface 505, the stationary body image moves from the position of the stationary body 502b toward the position of the stationary body image 502e.

  3A to 3C show images at each moment in the positional relationship shown in FIGS. 3A to 3C, the moving body images 501b, 501c, and 501f are captured at the center of the imaging angle of view 507. In contrast, the background stationary body has moved from the position of the stationary body image 502b to the position of the stationary body image 502d. As a result, as shown in FIG. 3D, it is possible to capture a panning image in which the moving body that is the subject is continuously captured at the center of the imaging angle of view 507. However, when images are taken by normal panning, the moving body images 501b, 501c, and 501f of the moving body that is the subject increase from FIG. 3A to FIG. 3C. As a result, as shown in FIG. 3D, the rear part away from the center of the imaging angle of view 507 in the moving body that is the subject becomes a flowing image. Note that the amount of background flow in the panning shot corresponds to the amount of background movement on the imaging surface from the stationary body image 502b at the start of exposure to the stationary body image 502d at the end of the normal panning exposure. If the speed at which the user pans the camera body 127 is constant, the amount of movement of the background on the imaging surface is determined by the exposure time. The longer the exposure time, the longer the time for the user to pan, and the greater the angle at which the camera body 127 is shaken during imaging. As a result, the amount of movement of the background on the imaging surface increases with the exposure time. In other words, in order to calculate the shutter speed appropriate for the desired flow rate, the desired flow rate is converted into the amount of movement of the background on the imaging surface, the user's panning speed is obtained, and the necessary shutter speed is calculated. That's fine. The method for calculating the shutter speed is a known technique and will not be described in detail here.

  Next, panning that zooms during exposure will be described. This embodiment implements zoom panning as described below. FIG. 4 is a diagram for explaining a change in the positional relationship between the subject and the background from the start of exposure to the end of exposure in zoom panning. FIG. 4A shows the start of exposure, FIG. 4B shows a certain temporary point from the start of exposure to the end of exposure, and FIG. 4C shows the end of exposure. FIGS. 5A to 5C show images at the respective moments in the positional relationship of FIGS. 4A to 4C. 4A to 4C, similarly to FIGS. 2A to 2C, the moving bodies 501a, 501c, and 501e, which are subjects that advance toward the right front toward the user, are captured at the center of the angle of view. This is an example of panning. The reference numerals in the figure basically correspond to those in FIGS. Also, in FIG. 4, the user performs a zooming operation so that the moving body images 501g and 501h during the zoom flow exposure have the same size as the moving body image 501b at the start of exposure on the virtual imaging surface 505. Therefore, from FIG. 4A to FIG. 4C, the angle of view changes so that the angle of view widens from the angle of view 507a at the start of zoom-out exposure to the angle of view 507b during the exposure of zoom-in. As a result, in the instantaneous images in the positional relationship of FIGS. 4A to 4C, the moving body images 501b, 501g, and 501h are picked up with the same size as shown in FIGS. 5A to 5C. obtain.

  In the zoom panning shot of FIG. 4, the field angle widens from the angle of view 507a at the start of the zoom panning exposure to the angle of view 507b during the zoom panning exposure. In this way, by changing the position of the condenser lens 504 to the wide side, the still body image 502e during the zoom panning exposure is more virtual than the stationary body image 502c during the normal panning exposure in FIG. 2B. It approaches the imaging of the moving body on the imaging surface 505. Similarly, the stationary body image 502f at the end of zoom flow exposure is closer to the imaging of the moving body on the virtual imaging surface 505 than the stationary body image 502d at the end of normal panning exposure in FIG. FIG. 5D is an image diagram of the panning image created by superimposing the images at the respective moments of FIGS. 5A to 5C in the same manner as FIG. 3D. The stationary body image on the virtual imaging surface 505 has a larger flow amount than the case of FIG. 3D due to the zooming operation in addition to the panning of the camera device 503.

  As described above, in normal panning shooting and zoom panning shooting, when imaging is performed with the same subject and the same exposure time, the captured images are different between the moving body as the subject and the stationary body as the background. In normal panning, the size of the moving object image on the virtual imaging surface 505 increases by the distance that the moving object approaches the user. On the other hand, in zoom panning, since the zooming operation is performed simultaneously with the panning of the camera device 503, the size of the moving object image on the virtual imaging surface 505 does not change. However, comparing the stationary object image on the virtual imaging surface 505 in FIG. 5B and FIG. 3B, the stationary object image 502e in the middle of the exposure while zooming out than the stationary object image 502c in the middle of the normal panning exposure is compared. However, the amount of movement from the moving object image 501b at the start of exposure becomes larger. Since zooming is performed in zoom panning, not only the panning amount of the camera device 503 but also the movement amount of the condenser lens 504 is added to the background flow amount. For this reason, in normal panning, if the desired amount of panning is converted into the amount of movement of the background on the imaging surface, the user's panning speed is obtained and the necessary shutter speed is calculated, the effect of an appropriate amount of panning can be obtained. It was possible to take an image with. However, in zoom panning, the amount of movement of the background on the imaging surface changes depending on both the panning and zooming operations of the user, so an image with an appropriate amount of sinking can be obtained simply by acquiring the panning speed. It is not possible to calculate the shutter speed at which imaging can be performed. In this way, in the shutter speed control corresponding to simply panning, the influence of the zooming operation is not taken into account, and therefore, when zoom panning is performed, an image portion in which the panning amount becomes larger than desired can be generated. . Therefore, in this embodiment, an appropriate shutter speed is calculated so that a desired background flow amount can be obtained in zoom panning. This will be described in detail below.

  FIG. 6 is a flowchart illustrating an example of a shutter speed calculation process for panning assist. The flowchart in FIG. 6 calculates shutter speeds for normal panning without zooming and panning with zooming. In step S <b> 201 of FIG. 6, the camera microcomputer 116 determines whether or not the user has set the panning mode by operating the operation switch 126. If an operation mode other than the panning mode is set, the camera microcomputer 116 repeats the process of step S201. If the panning mode is set, the camera microcomputer 116 advances the process to step S202. In step S202, the background flow amount setting means 117 of the camera microcomputer 116 acquires the background flow amount set by the user. The background sink amount set by the user may be a setting indicating the level of the sink amount, such as small, medium, and large. In step S <b> 203, the angular velocity calculation unit 118 of the camera microcomputer 116 acquires the angular velocity of the subject from the angular velocity sensor 123 of the camera body 127. Since the method for calculating the angular velocity of the subject is a known technique, description thereof is omitted here. In step S204, the zooming detection means 109 of the lens microcomputer 107 acquires the position information of the zoom lens 102 from the encoder 106 at a predetermined time interval. The zooming detection unit 109 calculates the focal length of the interchangeable lens 100 from the plurality of position information acquired from the encoder 106. The zooming detection means 109 transmits the calculated focal length information to the exposure time control means 119 of the camera microcomputer 116 through the lens mount 110 and the main body mount 122.

  In step S205, the exposure time control means 119 determines whether or not the user is performing a zooming operation based on the focal lengths obtained at predetermined time intervals in step S204. The exposure time control unit 119 serving as a selection unit determines that the user is not performing a zooming operation when the focal length is not changed or when the temporal change amount of the focal length is smaller than the threshold value. In this case, since it is considered that the user is performing normal panning, the exposure time control unit 119 advances the process to step S206. In step S206, the exposure time control unit 119 acquires and stores the focal length of the zoom lens 102 transmitted from the lens microcomputer 107 again. In step S207, the exposure time control means 119 calculates the shutter speed for normal panning based on the focal length, the amount of sink, and the main subject angular velocity acquired in step S206 (shutter speed in the second mode). Calculation). The shutter speed for panning is the exposure time during panning. The exposure time control means 119 calculates a shutter speed tv in normal panning based on the following formula 1. Here, α is a value corresponding to the amount of background flow set by the user with the operation switch 126. f is the focal length of the interchangeable lens 100. The exposure time control means 119 acquires focal length data in the interchangeable lens 100 through the main body mount 122. ω is the angular velocity of the main subject obtained from the camera angular velocity of the angular velocity sensor 123 of the camera body 127. Then, for example, by setting the background sink effect α to a predetermined value so that the amount of movement of the background portion on the image plane is, for example, 800 μm, It can be constant regardless of the panning speed. Thereafter, when the switch is operated for normal panning, the camera microcomputer 116 captures an image with an automatically set shutter speed TV. Thereby, even if the user is unfamiliar with the panning, the user can easily capture an image having an appropriate panning effect.

    TV = α / f / ω (Formula 1)

  On the other hand, in step S205, when the temporal change amount of the focal length of the interchangeable lens 100 changes by a predetermined amount or more, the exposure time control unit 119 determines that the user is performing a zooming operation. In this case, since it is considered that the user is performing zoom panning, the exposure time control unit 119 advances the processing to step S208. In step S208, the exposure time control unit 119 calculates a zooming speed. The exposure time control unit 119 calculates a temporal change amount of the focal length based on the focal length of the zoom lens 102 transmitted from the zooming detection unit 109, and calculates a zooming speed. When performing zoom panning, the user follows the subject while rotating the zoom ring of the interchangeable lens 100 and changing the focal length of the interchangeable lens 100. Here, it is assumed that the user rotates the zoom ring of the interchangeable lens 100 at a constant speed and performs panning at a constant zooming speed. When the temporal change amount of the focal length is calculated in step S208, the process proceeds to step S209, and the shutter speed for zooming is calculated based on the temporal change amount of the focal length, the flow amount, and the angular velocity of the main subject calculated in step S208. (Shutter speed calculation in the first mode). A method for calculating the shutter speed for zooming in step S209 will be described with reference to FIG.

  FIG. 7 is a diagram for explaining the positional relationship between the subject and the background in zoom panning. FIG. 7A shows the positional relationship between the subject and the background when exposure is started. FIG. 7B shows the positional relationship of the subject when the exposure is completed. In FIG. 7, the subject progresses diagonally forward from the left back toward the right front with reference to the user. FIG. 7A shows the main subject 301 at the start of exposure as an imaging target, one point 302 in the background behind the main subject 301 at the start of exposure, and the exposure reflected by the main subject 301 at the start of exposure. A ray 303 of the main subject at the start is shown. In addition, a point of light ray 304 of the background part reflected by the point 302 of the background part is shown. Further, FIG. 7A shows a virtual zoom lens 305 that simply shows the zoom lens 102 in the interchangeable lens 100, an imaging surface 306 on the imaging device 112 disposed in the camera body 127, and Is shown. In addition, an angle of view 307 at the start of exposure, which is an imaging range projected on the imaging surface 306, is illustrated. The light beam reflected by the main subject 301 and the background point 302 at the start of exposure is condensed at the center of the virtual zoom lens 305 and formed on the imaging surface 306. In this embodiment, in order to simplify the description, in FIGS. 7A and 7B, the main subject 301 at the start of exposure is captured at the center of the imaging surface 306. That is, the light beam 303 of the main subject at the start of exposure coincides with the optical axis of the interchangeable lens 100. In FIG. 7A, the angle formed by the light ray 303 of the main subject at the start of exposure and the light ray 304 at one point in the background is defined as θ1. A distance from the center of the virtual zoom lens 305 to the imaging surface 306 is defined as a focal length f1 of the virtual zoom lens 305. The distance between the image of the point 302 on the imaging surface and the optical axis is x1.

  FIG. 7B further shows a main subject 308 after the exposure, a light beam 309 of the main subject at the end of exposure reflected by the main subject 308 after the exposure, an angle of view 310 at the end of the exposure, Is shown. In FIG. 7B, the angle formed between the light beam 309 of the main subject at the end of exposure and the light beam 304 at one point in the background is θ2. A distance from the center of the virtual zoom lens 305 to the imaging surface 306 is defined as a focal length f2 of the virtual zoom lens 305. The distance between the image of the point 302 on the imaging surface and the optical axis is x2. Then, by changing the focal length from f1 to f2, the angle of view is widened from the angle of view 307 at the start of exposure to the angle of view 310 at the end of exposure. If the angular velocity of the main subject obtained from the angular velocity sensor 123 is ω and the shutter speed for zooming is TZ, the angle formed between the main subject light ray 303 at the start of exposure and the main subject light ray 309 at the end of exposure. Becomes ω · TZ. The background sink effect α is represented by the amount of movement of one point 302 on the background portion on the imaging surface 306 as shown in the following formula 2. 7A, the distance between the image of the point 302 on the imaging surface at the start of exposure and the optical axis is expressed by the following equation (3). From FIG. 7B, the distance x2 between the image of the point 302 on the imaging surface at the end of the exposure and the optical axis is expressed by the following equation (4). At this time, assuming that θ1 and (θ2−ω · TZ) are sufficiently small, “tan θ1≈θ1” and “tan (θ2−ω · TZ) ≈θ2−ω · TZ” are obtained. Therefore, the background flow amount α can be transformed as shown in Equation 5 below. Further, assuming that the shutter speed in zoom panning is sufficiently short, θ1 and θ2 are substantially equal, so the background sinking amount α can be transformed as shown in the following equation (6). Furthermore, when the zooming speed is VZ, f2 = f1 + VZ · TZ, and therefore the background flow amount α can be transformed as shown in the following equation (7). The background flow amount α can be expressed as a TZ polynomial. In these equations, “·” means multiplication. “^ 2” means square.

α = x1−x2 (Formula 2)
x1 = f1 · tan θ1 (Formula 3)
x2 = f2 · tan (θ2−ω · TZ) (Formula 4)
α = x1−x2 = f1 · θ1−f2 · (θ2−ω · TZ) (Formula 5)
α = (f1−f2) θ2 + f2 · ω · TZ (Expression 6)
α = (f1 · ω−VZ · θ1) TZ + ω · f2 · TZ ^ 2 (Expression 7)

  The exposure time control means 119 provided in the camera main body 127 calculates the shutter speed TZ for zoom panning based on the relationship of the above formula 7, similarly to the shutter speed for normal panning. The exposure time control unit 119 can acquire the zooming speed VZ of the zoom lens 102 from the zoom lens 102 through the main body mount 122. As a result, the exposure time control unit 119 can calculate an appropriate shutter speed in zoom panning so that the background sink amount set by the user can be obtained.

  FIG. 8 is a diagram for explaining how the background flows in a captured image by zoom panning. FIG. 8 shows an image obtained by focusing on a subject moving from the left back to the right front by focusing on the center of the angle of view by zoom panning as in FIG. Further, for the sake of explanation, a dividing line that divides the image into three parts in the vertical and horizontal directions is shown. The thin solid-line arrows shown in the peripheral divided areas in FIG. 8 indicate the background flow amount and the flow direction vector generated in each divided area when the user pans the camera body 127 leftward. This fine solid line vector is defined as a panning vector 401. The dotted arrows in FIG. 8 indicate vectors of the background flow amount and the flow direction generated in each divided region when the user zooms the interchangeable lens 100. This fine dotted line vector is referred to as a zooming vector 402. The thick solid-line arrows in FIG. 8 indicate the background flow amount and the flow direction vector generated in each divided area in zoom panning. This thick solid line vector is set as a zoom flow vector 403. The zoom sink vector 403 is a vector obtained by synthesizing a thin solid line panning vector 401 and a dotted line zooming vector 402.

  As shown in FIG. 8, the panning vector 401 is constant everywhere in the angle of view. On the other hand, the direction of the zooming vector 402 differs depending on the position within the angle of view. A zooming vector 402 in FIG. 8 is a vector extending in a radial direction from the center of the angle of view. Here, a divided region on the front side in the traveling direction of the subject is a right divided region 404, and a divided region on the rear side (reverse side) in the traveling direction of the subject is a left divided region 405. In the right divided area 404, the vector direction of the zooming vector 402 is the right direction, but in the left divided area 405, the vector direction of the zooming vector 402 is the left direction. Thus, the vector direction of the zooming vector 402 differs depending on the area within the angle of view. As a result, the zoom flow vector 403, which is a combined vector of the panning vector 401 and the zooming vector 402, in each divided region has different vector directions. For example, in FIG. 8, the panning vector 401 and the zooming vector 402 in the right division area 404 are in the same right direction. For this reason, the zoom flow vector 403 of the right divided area 404 is in the right direction, and the size thereof is the sum of the panning vector 401 and the zooming vector 402. The amount of background flow in the right divided area 404 increases. On the other hand, the panning vector 401 in the left divided region 405 is in the right direction, whereas the zooming vector 402 is in the opposite left direction. The panning vector 401 and the zooming vector 402 cancel each other. For this reason, the zoom flow vector 403 of the left divided area 405 becomes small. When the size of the zoom sink vector 403 is zero, the background sink amount in the left divided area 405 is eliminated. Thus, in zoom panning, the amount of background sinking in zoom panning varies depending on the position within the angle of view.

  In the present embodiment, the area in which the background flow amount α is set is automatically set by the background flow amount setting means 117 in the area ahead of the main subject in the traveling direction. Hereinafter, the setting of the background flow amount α will be described in detail. In step S209, the camera signal processing circuit 114 divides the image obtained by the image sensor 112 into three parts vertically and horizontally as shown in FIG. 8, and generates nine divided regions for the image data. Then, the angular velocity calculation unit 118 determines the traveling direction of the main subject from the angular velocity data acquired by the angular velocity sensor 123. The background flow amount setting unit 117 acquires the position information of the main subject within the angle of view from the camera signal processing circuit 114 and acquires the traveling direction information of the main subject from the angular velocity calculation unit 118. Then, the background flow amount setting unit 117 extracts an area corresponding to the main subject in the traveling direction from the main subject position information and the traveling direction information. In the example of FIG. 8, the main subject is located at the center of the angle of view and progresses from left to right. In this case, the background flow amount setting means 117 selects the right divided region 404 as a setting region for the background flow amount α. In this case, the background sink amount setting unit 117 calculates the shutter speed tz for zoom panning based on the relationship of the above expression 7 so that the background sink amount in the right divided area 404 becomes the set sink amount α. To do.

  As described above, in the present embodiment, the first mode and the second mode are selected based on the detected temporal change amount of the focal length in the panning imaging mode. Specifically, in the present embodiment, for example, when the temporal change amount of the focal length due to zoom or the like is equal to or greater than the threshold, the first mode is selected, and based on the temporal change amount of the focal length and the angular velocity of the subject. The exposure time is determined. On the other hand, in the present embodiment, for example, when the amount of temporal change in focal length is less than the threshold, the second mode is selected, and the exposure time is based on the focal length of the imaging optical system and the angular velocity of the subject. To decide. Therefore, in the present embodiment, in the panning shooting mode, even when the focal length changes due to zoom or the like, an image including a suitable panning effect can be easily obtained as in the case of normal panning without the focal length changing. Obtainable.

  Further, in the present embodiment, the background sink amount in zoom panning is set, and the exposure time of zoom panning is set not only from the temporal change amount of the focal length and the angular velocity of the subject but also from the set background sink. The amount is also determined. In particular, as the amount of background flow, the amount of flow for the background in the region ahead of the moving direction of the main subject is set. In this case, the background of the area in front of the moving direction of the main subject can be imaged so as to flow with the set sink amount. Therefore, in this embodiment, in zooming during panning, excessive exposure of the background due to zooming that does not occur in panning is less likely to occur, and the exposure time is determined so that the background flows in a desired amount. it can. The user can easily obtain an image including a desired sink effect by zoom panning. It should be noted that the background flow amount to be set may not be changeable. In this case, the background flow amount setting means 117 for setting the flow amount is unnecessary.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included.

  For example, in the above-described embodiment, the region that has the background flow amount α is a divided region on the front side in the traveling direction of the main subject. In addition to this, for example, the background flow amount setting unit 117 may set the designated divided region as a region having the background flow amount α based on the designation of the divided region by the user. As described above, even when the user designates a region for setting the background sink amount, the user can easily obtain an image including a desired effect by zoom panning, as in the above-described embodiment. A user who is accustomed to zoom panning can specify a divided region where the background is the amount of flow α and obtain an image having a desired zoom panning effect.

  In the above embodiment, the user performs a zooming operation of the interchangeable lens 100 during zoom panning. In addition to this, for example, the camera microcomputer 116 may perform zooming control in zoom panning.

  In the above embodiment, in zoom panning, the user operates the orientation of the imaging device 1 in accordance with the movement of the main subject. In addition to this, for example, the interchangeable lens 100 may drive the imaging lens unit 101 so as to maintain the angle of view of the main subject during exposure of zoom panning. As described above, the interchangeable lens 100 drives the imaging lens unit 101 to maintain the angle of view of the main subject during the exposure of zoom panning, thereby reducing the main subject's displacement and enabling clear imaging.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to the apparatus which mainly aimed at imaging like a digital camera. The present invention can be applied to any device with a built-in or externally connected imaging device, such as a mobile phone, personal computer (laptop type, desktop type, tablet type, etc.), game machine, and the like. Therefore, the “imaging device” in this specification is intended to include any electronic device having an imaging function.

  In addition, the present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors of a computer of the system or apparatus execute the program. It can also be realized by a process of reading and executing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 1 Imaging device 100 Interchangeable lens 101 Imaging lens unit 102 Zoom lens 103 Focus lens 104 Zoom lens drive means 109 Zooming detection means 112 Imaging element 117 Background flow amount setting means 118 Angular velocity calculation means 119 Exposure time control means 127 Camera body

Claims (8)

An image pickup means for picking up a subject image incident via the image pickup optical system;
Detecting means for detecting a temporal change amount of a focal length of the imaging optical system;
Angular velocity calculating means for calculating an angular velocity corresponding to the amount of movement of the subject;
Exposure time control means for determining the exposure time,
The exposure time control means is in a panning imaging mode.
Determining the exposure time based on the amount of change in the focal length detected by the detecting means and the angular velocity of the subject calculated by the angular velocity calculating means;
An imaging apparatus characterized by that. Selecting means for selecting a first mode and a second mode based on a temporal change amount of the focal length detected by the detecting means;
The exposure time control means includes
When the first mode is selected by the selection unit, the exposure time is determined based on a temporal change amount of the focal length and an angular velocity of the subject,
When the second mode is selected by the selection unit, the exposure time is determined based on a focal length of the imaging optical system and an angular velocity of the subject;
The imaging apparatus according to claim 1. The selection unit selects the first mode when the temporal change amount of the focal distance is equal to or greater than a threshold, and selects the second mode when the temporal change amount of the focal distance is less than the threshold.
The imaging apparatus according to claim 2. A background sink amount setting means for setting the background sink amount in zoom panning is provided.
The exposure time control means includes a temporal change in focal length detected by the zooming detection means, an angular velocity of the subject calculated by the angular velocity calculation means, and a background flow amount set by the background flow amount setting means. To determine the exposure time for zoom panning,
The imaging apparatus according to claim 1. The background sink amount setting means sets the sink amount for the background of the area in front of the moving direction of the main subject;
The imaging apparatus according to claim 4. The background flow amount setting means sets a flow amount for the background of the area designated by the user.
The imaging apparatus according to claim 4. A method for controlling an imaging apparatus that captures a subject image incident through an imaging optical system,
A detection step of detecting a temporal change amount of a focal length of the imaging optical system;
An angular velocity calculating step for calculating an angular velocity corresponding to the amount of movement of the subject;
An exposure time control step for determining an exposure time;
With
In the exposure time control step in the panning shooting mode,
The exposure time is determined based on the amount of change in focal length detected by the detection step and the angular velocity of the subject calculated by the angular velocity calculation step.
And a method of controlling the imaging apparatus. A program that causes a computer to execute a control method of an imaging device that captures an image of a subject incident through an imaging optical system,
The control method of the imaging device is:
A detection step of detecting a temporal change amount of a focal length of the imaging optical system;
An angular velocity calculating step for calculating an angular velocity corresponding to the amount of movement of the subject;
An exposure time control step for determining an exposure time;
With
In the exposure time control step in the panning shooting mode,
The exposure time is determined based on the amount of change in focal length detected by the detection step and the angular velocity of the subject calculated by the angular velocity calculation step.
A program characterized by that.

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