Imaging device, image processing method and program

Abstract

According to one embodiment, an imaging device includes a first acquisition module, a second acquisition module, a calculation module, and a display control module. The first acquisition module is used to acquire a captured image of a celestial body taken by an imaging unit. The second acquisition module is configured to acquire physical quantities detected by a plurality of detectors at least related to the position and attitude of the imaging device. The calculation module is configured to calculate the amount of motion and the rotation angle of the celestial body contained in the captured image based on the physical quantities of the imaging device, and to calculate the maximum exposure time for which the celestial body contained in the captured image is tracked. The display control module is configured to cause the display unit to display the captured image on which information related to the maximum exposure time is superimposed.

Description

Technical Field

[0001] The present invention relates to an imaging device, an image processing method, and a program. Background Art

[0002] When shooting the starry sky (night sky) using an imaging device, when performing a long exposure, the positions of stars or celestial bodies change due to the diurnal motion of celestial bodies related to the rotation of the earth. Therefore, even if you want to shoot stars in the starry sky as point images by long exposure, you usually use an equatorial mount to compensate for the diurnal motion. By using an equatorial mount, you can shoot celestial bodies while tracking celestial bodies that move diurnally. However, an equatorial mount is a special device that requires specialized setup work.

[0003] Therefore, a method is disclosed which compensates for the diurnal motion of a celestial body using the image stabilization function of an imaging device without using a specially mounted device such as an equatorial mount, and photographs the celestial body in the starry sky as a point image.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1]

[0007] Japanese published patent application 2014-209795 Summary of the invention

[0008] [Problems to be Solved by the Invention]

[0009] However, since the image stabilization function has a limited range of motion, the day and night motion compensation using the image stabilization function naturally has a limited exposure time. In this case, even if the user sets the exposure time in advance, since it is not possible to shoot within the specified exposure time exceeding the maximum exposure time due to the limited range of motion, the exposure is stopped at the maximum exposure time, thereby performing the shooting operation within the exposure time not intended by the user.

[0010] The present invention is proposed in view of the above-mentioned problems, and an object of the present invention is to provide an imaging device, an image processing method and a program, which can capture a celestial body as a point image within the user's intended exposure time by checking the maximum exposure time.

[0011] [Solution to the problem]

[0012] In order to solve the above problems and achieve the purpose, the imaging device includes a first acquisition module, a second acquisition module, a calculation module and a display control module. The first acquisition module is configured to acquire a captured image of a celestial body taken by an imaging unit. The second acquisition module is configured to acquire physical quantities detected by multiple detectors at least related to the position and posture of the imaging device. The calculation module is configured to calculate the movement amount and rotation angle of the celestial body contained in the captured image based on the physical quantities of the imaging device, and calculate the maximum exposure time for the celestial body contained in the captured image to be tracked. The display control module is configured to enable the display unit to display the captured image, on which information related to the maximum exposure time is superimposed.

[0013] [Effects of the invention]

[0014] According to one embodiment of the present invention, by checking the maximum exposure time, a celestial object can be photographed as a point image within the user's intended exposure time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram showing an example of a hardware configuration of an imaging device according to an embodiment;

[0016] Figure 2 It is a diagram that shows that the speed of celestial bodies varies with the declination of the celestial sphere;

[0017] Figure 3 It is a diagram illustrating the motion of celestial bodies centered on the celestial north pole;

[0018] Figure 4 is a schematic diagram showing that the maximum exposure time varies depending on the location where the night sky is framed;

[0019] Figure 5 It is a diagram illustrating how the appearance of a celestial body's orbit changes according to the elevation angle;

[0020] Figure 6 It is a diagram illustrating how the appearance of a celestial body's orbit changes according to the elevation angle;

[0021] Figure 7 is a schematic diagram illustrating physical quantities detected by various sensors of an imaging device according to an embodiment;

[0022] Figure 8 is a schematic diagram illustrating a celestial sphere when the imaging apparatus according to the embodiment photographs a celestial body;

[0023] Fig. 9 is a schematic diagram illustrating a state in which an imaging device according to an embodiment tracks a celestial body when the celestial body obviously moves in an elliptical (circular) orbit;

[0024] Fig.10is a diagram illustrating the relationship between an ellipse and a tangent line;

[0025] Fig.11 is a schematic diagram showing an example of a functional block configuration of an imaging device according to an embodiment;

[0026] Fig.12 is a schematic diagram for explaining an operation of obtaining a maximum exposure time of another area by interpolating the maximum exposure time of sampling points within a frame in an imaging device according to an embodiment;

[0027] Fig.13 is a schematic diagram showing an example of a display mode of a maximum exposure time within a frame and a framing operation of an imaging device according to an embodiment;

[0028] Fig.14 is a flowchart showing an example of the flow of a maximum exposure time display process and a tracking shooting process of an imaging device according to an embodiment;

[0029] Fig.15 is a schematic diagram showing an example of the operation of a display area that cannot be compensated within a frame captured by the imaging device according to the embodiment; and

[0030] Fig.16 : is a schematic diagram showing an example of a display mode of the length of the photocapable starlight trail within a frame photographed by the imaging device according to the embodiment. DETAILED DESCRIPTION

[0031] In the following, reference will be made to Figures 1 to 16 Embodiments of the imaging device, image processing method and program according to the present invention are described in detail. In addition, the present invention is not limited to the following embodiments, and the components in the following embodiments include components that are easily conceived by those skilled in the art, substantially the same components, and so-called equivalents. In addition, various omissions, substitutions, changes and combinations of components may be made without departing from the spirit of the following embodiments.

[0032] Hardware configuration of imaging equipment

[0033] Figure 1 A schematic diagram showing a hardware configuration of an imaging device 1 according to an embodiment. Figure 1 The hardware configuration of the imaging device 1 according to the present embodiment is described.

[0034] Figure 1 The imaging device 1 shown is an imaging device such as a smartphone and a tablet terminal having a camera function. It should be noted that in the present embodiment, the imaging device 1 will be described as a smartphone.

[0035] like Figure 1As shown, the imaging device 1 includes a central processing unit (CPU) 501, a read-only memory (ROM) 502, a random access memory (RAM) 503, a flash memory 504, a touch panel 505, a display 506, an external device connection I / F (interface) 507, a communication circuit 508 and a positioning signal receiver 509.

[0036] The CPU 501 is an arithmetic device that controls the operation of the entire imaging device 1. The ROM 502 is a nonvolatile memory for storing a program that is first executed by the CPU 501, such as an initial program loader (IPL). The RAM 503 is a volatile memory used as a work area of ​​the CPU 501. It should be noted that, for example, the CPU 501, the ROM 502, and the RAM 503 may be configured by a system on chip (SoC) mounted on one board.

[0037] The flash memory 504 is a nonvolatile memory and stores various programs such as a web browser and various data according to the control of the CPU 501 .

[0038] The touch panel 505 is an input device capable of operating the imaging device 1 by a user's touch operation. For example, the touch panel 505 operates based on a capacitance sensing method, a resistance film method, etc. It should be noted that the touch panel 505 corresponds to an "operation unit".

[0039] The display 506 is a liquid crystal display, an organic electroluminescent display, or the like, and is integrated with the touch panel 505 , and displays an image of the main body, various icons, etc. It should be noted that the display 506 corresponds to a “display unit”.

[0040] The external device connection I / F 507 is an interface based on a standard such as USB (Universal Serial Bus), and performs data communication through connection with an external device.

[0041] The communication circuit 508 is a communication circuit that performs wireless communication with an external device via a network through an antenna 508a based on a communication method such as Wi-Fi (registered trademark), 4G (fourth generation mobile communication system), and 5G (fifth generation mobile communication system).

[0042] The positioning signal receiver 509 is a receiving device that receives a positioning signal from a positioning satellite based on a global navigation satellite system (GNSS). The positioning signal receiver 509 detects the latitude of the position of the imaging device 1 based on the received positioning signal.

[0043] like Figure 1As shown, the imaging device 1 also includes a lens 511, a focal length detector 511a, an imaging sensor 512, a driving unit 513, an image processing unit 514, an imaging control unit 515, a geomagnetic sensor 516, a posture sensor 517 and an acceleration sensor 518.

[0044] The lens 511 is an optical system that collects light from a subject to form an image with the imaging sensor 512. The focal length detector 511a is a device that detects the focal length of the lens 511.

[0045] The imaging sensor 512 is an image sensor configured by CMOS (Complementary Metal Oxide Semiconductor), CCD (Charge Coupled Device), etc., and the imaging sensor converts the light incident on the lens 511 into image data of an electrical signal and outputs the image data. The optical axis OA of the lens 511 is orthogonal to the imaging surface 512a of the imaging sensor 512.

[0046] The driving unit 513 is a unit including a fixed stage, a movable stage movable relative to the fixed stage, and an electromagnetic circuit that moves the movable stage. The imaging sensor 512 is held on the movable stage, and the parallel movement of the imaging sensor is controlled to a desired movement speed in a direction orthogonal to the optical axis OA, and the rotational movement of the imaging sensor is controlled to a desired rotational speed around an axis parallel to the optical axis OA. The image stabilization function is achieved by controlling the imaging sensor 512 using the driving unit 513.

[0047] The image processing unit 514 is a unit that receives image data captured by the imaging sensor 512 , performs processing on the image data, and outputs the processed image data.

[0048] The imaging control unit 515 is a unit that controls the imaging operation of the imaging sensor 512 and the operation of the driving unit 513 according to instructions from the CPU 501 .

[0049] The geomagnetic sensor 516 is a sensor that detects the earth's magnetism to detect the angle of the imaging direction of the imaging device 1 as an azimuth.

[0050] The attitude sensor 517 is a sensor that detects an elevation angle and a rotation angle. The elevation angle is the angle between the imaging direction of the imaging device 1 and the horizontal plane, and the rotation angle is the angle of rotation around the optical axis OA from the reference position of the imaging sensor 512.

[0051] The acceleration sensor 518 is a sensor that detects acceleration of the imaging device 1 in three-axis directions to detect the inclination, parallel movement, movement speed, displacement, and the like of the imaging device 1 .

[0052] CPU 501, ROM 502, RAM 503, flash memory 504, touch panel 505, display 506, external device connection I / F 507, communication circuit 508, positioning signal receiver 509, focal length detector 511a, image processing unit 514, imaging control unit 515, geomagnetic sensor 516, posture sensor 517 and acceleration sensor 518 are connected via a bus 520 such as an address bus and a data bus so as to be able to communicate with each other.

[0053] Figure 1 The hardware configuration of the imaging device 1 shown is only an example. Therefore, the imaging device does not necessarily include all components, and the imaging device may include another component. For example, the imaging device 1 may include a GPU (Graphics Processing Unit) that performs real-time image processing, a near field communication circuit that performs near field wireless communication through a communication standard such as NFC (Near Field Communication) and Bluetooth (registered trademark), and the like.

[0054] The difference in the speed of movement of celestial bodies on the celestial sphere

[0055] Figure 2 It is a schematic diagram that illustrates how the speed of celestial bodies' movement varies with the declination of the celestial sphere. Figure 3 It is a schematic diagram illustrating the motion of celestial bodies centered on the celestial north pole. Figure 4 is a diagram showing the maximum exposure time depending on the location where the night sky is viewed. The difference in motion speed depends on the position of the celestial body (star) on the celestial sphere, which will be referred to as Figure 2 and Figure 4 describe.

[0056] like Figure 2 As shown in (a), on the celestial sphere CS, a celestial body located at a declination δ from the celestial equator CE moves while drawing a circular orbit OB around the celestial north pole NCP. In other words, Figure 3 As shown, the user (observer) observes that each celestial body (star) in the starry sky rotates counterclockwise along a concentric orbit OB around the celestial body's north pole NCP. Figure 3 As shown in FIG. 1 , the celestial body moves a greater distance in a predetermined time and has a greater movement speed because the celestial body is farther from the celestial north pole NCP, that is, the celestial body has a smaller declination δ. Figure 2 As shown in (b), the celestial body with a declination δ of about 90 degrees (such as the North Star), that is, the celestial body located near the celestial north pole NCP, has a motion speed of about zero, but the celestial body existing on the celestial equator CE has the maximum motion speed (motion speed is D). In other words, the celestial body on the celestial sphere CS has a motion speed determined by the declination δ. In this case, Figure 2As shown in (b), as the declination δ becomes smaller, the movement speed becomes larger, and the movement speed increases in the order of movement speed A, B, C and D.

[0057] As described above, even if the image stabilization function is implemented by performing parallel motion control and rotational motion control on the imaging sensor 512 using the drive unit 513, the function can perform tracking shooting while exposing a celestial body included in the frame (image capturing range) framed by the imaging device 1. However, because the movable range of the imaging sensor 512 moved by the drive unit 513 has a mechanical limit, that is, a limit to the range of variation of the positional relationship between the imaging sensor 512 and the lens 511, the time that can be exposed while tracking the celestial body also has a limit. Here, the time that can be exposed while tracking the celestial body is referred to as the maximum exposure time.

[0058] As described above, because the farther the celestial body is from the celestial north pole NCP, the faster the celestial body moves, so the speed of the celestial body contained in the frame F1 capturing the vicinity of the North Star is less than the speed of the celestial body contained in the frame F2 captured at a position far from the North Star. Figure 4 As shown. In other words, the maximum exposure time when tracking shooting is performed on a celestial body in frame F1 (for example, 30 seconds) is greater than the maximum exposure time when tracking shooting is performed on a celestial body in frame F2 (for example, 10 seconds). Here, among the celestial bodies included in a specific frame, for example, when the celestial body with the smallest maximum exposure time has a maximum exposure time of 10 seconds, and the celestial body with the largest maximum exposure time has a maximum exposure time of 30 seconds, the maximum exposure time of the entire frame is 10 seconds. Therefore, the maximum exposure time is different depending on the celestial body included in the frame determined by the user according to the imaging direction of the imaging device 1.

[0059] Differences in the appearance of celestial body orbits due to elevation angle

[0060] Figure 5 and Figure 6 is a schematic diagram illustrating how the appearance of a celestial body orbit changes according to the elevation angle. Figure 5 and Figure 6 .

[0061] like Figure 5 As shown, even if the orbit OB drawn by the celestial body on the celestial sphere CS is a circular orbit, the case of observing the circular orbit from directly below is (A1), the case of observing the circular orbit from a certain angle is (A2) and (A3), and the case of observing the circular orbit from the side is (A4), then the shape of each orbit OB observed is different, as shown in FIG. Figure 6In other words, when a user uses the imaging device 1 to take a starry sky image, the elevation angle h of the imaging direction of the imaging device 1 affects the imaging state of the orbit OB of the celestial body. For example, when the imaging direction of the imaging device 1 is as Figure 5 When the elevation angle is h as in the cases (A2) to (A4) in FIG. 1 , the orbit OB of the observed celestial body is as follows: Figure 6 A portion of a circular track is shown.

[0062] Physical quantity detected by imaging equipment

[0063] Figure 7 1 is a schematic diagram for explaining physical quantities detected by various sensors of the imaging device according to the embodiment. Figure 8 Schematic diagram of the celestial sphere when the imaging device according to the embodiment photographs a celestial body. Figure 7 and Figure 8 Physical quantities and the like that can be detected by various sensors of the imaging device 1 are described.

[0064] like Figure 7 As shown in (a), the positioning signal receiver 509 of the imaging device 1 can detect the latitude ε, which is an angle in the direction toward the North Pole NP, which is formed by the equator E and the camera point O of the imaging device 1 on the earth ER.

[0065] like Figure 7 As shown in (b), the geomagnetic sensor 516 of the imaging device 1 can detect the geomagnetism as the earth's magnetic force to detect the angle of the imaging direction of the imaging device 1 (for example, the clockwise angle relative to the north direction) as the azimuth A.

[0066] like Figure 7 As shown in (c), the posture sensor 517 of the imaging device 1 can detect the elevation angle h, which is the angle between the horizontal plane of the imaging device 1 and the imaging direction (i.e., the optical axis OA). Figure 7 As shown in (d), the posture sensor 517 can detect the rotation angle ξ around the center C of the imaging sensor 512 (the optical axis OA of the lens 511) from the horizontal plane.

[0067] like Figure 8As shown, it is assumed that on the celestial sphere CS, the zenith is Z, the point where the horizontal plane intersects the celestial sphere CS in the due north direction is N, and the celestial body existing in the imaging direction of the imaging device 1 is S. In this case, the angle between the horizontal plane and the direction from the shooting point O to the celestial body S is the elevation angle h. In addition, the angle between the direction from the shooting point O to the point N and the direction in which the celestial body S exists is the azimuth angle A. The azimuth angle corresponds to the angle formed by the shortest curve connecting the zenith Z and the celestial north pole NCP and the shortest curve connecting the zenith Z and the celestial body S. In addition, the latitude ε detected by the positioning signal receiver 509 corresponds to the angle formed by the point N, the shooting point O, and the celestial north pole NCP.

[0068] Furthermore, the angle formed by the shortest curve connecting the zenith Z and the celestial north pole NCP and the shortest curve connecting the celestial body S and the celestial north pole NCP corresponds to the hour angle H. Here, the angle formed by the shortest curve connecting the celestial north pole NCP and the celestial body S and the shortest curve connecting the zenith Z and the celestial body S is γ.

[0069] Furthermore, assuming that the declination of the celestial body S is δ, the angle θ formed by the celestial body S, the photographing point O, and the celestial body north pole NCP corresponds to 90-δ.

[0070] The amount of motion of a celestial body per unit time

[0071] Fig. 9 is a schematic diagram illustrating a state in which the imaging device according to the embodiment tracks a celestial body when the celestial body apparently moves on an elliptical (circular) orbit. Fig.10 is a diagram illustrating the relationship between an ellipse and a tangent line. Fig. 9 and Fig.10 The amount of motion per unit time on the imaging surface 512a of the imaging sensor 512 is described. From the perspective of a user observing from a location far from the North Pole (i.e., far from the Earth's axis) and the Earth rotating, the following calculation of the amount of motion of the celestial body will be derived on the premise of an ellipse, considering that the apparent orbit of the celestial body may have a slightly elliptical shape. However, since the apparent orbit is actually regarded as a perfect circular orbit, and the ellipse conceptually includes a perfect circle, the expression for calculating the amount of motion based on the ellipse is also applicable to the perfect circular orbit.

[0072] The amount by which the celestial body S moves in the X direction (horizontal direction) and the Y direction (vertical direction) on the celestial sphere CS in a unit time can be obtained as the amount of motion and the rotation angle in a unit time on the imaging surface 512a of the imaging sensor 512 of the imaging device 1. In this case, it is assumed that when the celestial body existing at the point S1 (center C) moves along the orbit OB (such as Fig. 9When the elliptical orbit (shown in FIG. 1 ) moves to point S1′ on the imaging surface 512a, the amount of movement in the X direction is Δx, the amount of movement in the Y direction is Δy, and the rotation angle is α. The rotation angle α is the inclination angle of the tangent line L at point S1′ on the ellipse of the celestial body orbit OB, that is, the angle between the tangent line of the ellipse at point S1 and the tangent line of the ellipse at point S1′. It should be noted that even if the orbit OB of the celestial body is described as an ellipse, the ellipse conceptually includes a perfect circle as described above.

[0073] Here, if Fig. 9 As shown, when the celestial body at point S1 moves along the orbit OB (such as Fig. 9 When the imaging sensor 512a moves along the elliptical orbit shown in FIG. 5 , if it is assumed that point S1 is the center C of the imaging surface 512a and the motion from point S1 to point S1′ is tracked, the driving unit 513 may move the imaging sensor 512 so that the center C moves by the motion amounts Δx and Δy. In addition, when another celestial body exists at point S2 around point S1, the other celestial body moves from point S2 to point S2′. In order to track the celestial body at point S2, the driving unit 513 may rotate the imaging sensor 512 around the center C at a rotation angle α.

[0074] Here, assuming that the focal length detected by the focal length detector 511a is f, and the rotation angle of the celestial body around the celestial north pole NCP is Φ, the motion amounts Δx and Δy are expressed by expressions (1) and (2), as disclosed in Japanese Laid-Open Patent Application 2014-209795 (known document).

[0075] Δx=f×sinθ×sinΦ (1)

[0076] Δy=f×sinθ×cosθ(1-cosΦ) (2)

[0077] exist Fig.10 In the ellipse of the XY coordinate system shown, the equation of the tangent line L of the ellipse at the point K on the ellipse is represented by the expression (3) disclosed in the above-mentioned known document.

[0078] x0×(x / a 2 )+y0×(y / b 2 )=1 (3)

[0079] When the equation of the tangent line L is modified into the equation of y, it is represented by expression (4).

[0080] y=-(b 2 ×x0) / (a 2 ×y0)×x-1 / (a 2 ×y0) (4)

[0081] The angle between the tangent line L of the ellipse and the X-axis is the rotation angle α of the image with the center C of the imaging sensor 512 as the rotation center. Fig. 9 In the example, the coordinates of point S1′ are assumed to be (x0, y0), because the inclination angle of the straight line Q perpendicular to the tangent line L at point S1′ of the elliptical orbit OB is -(b 2 ×x0) / (a 2 ×y0), the rotation angle α to be obtained is expressed by expression (5).

[0082] α=arctan{(-b 2 ×x0) / (a 2 ×y0)} (5)

[0083] In addition, based on the tangent theorem, etc., it is expressed by expression (6) Figure 8 The angle γ in is as disclosed in the above-mentioned known documents.

[0084] γ=arctan[cos(ε)×sin(A) / {sin(ε)×cos(h)-cos(ε)×sin(h)×cos(A)}](6)

[0085] The celestial body's motion amounts x and y are converted into motion amounts Δx and Δy in coordinates on the imaging surface 512a by using the angle γ obtained by expression (6), and the motion amounts Δx and Δy are represented by expressions (7) and (8) as disclosed in the above-mentioned known literature.

[0086] Δx=x×cos(γ)+y×sin(γ) (7)

[0087] Δy=x×sin(γ)+y×cos(γ) (8)

[0088] In addition, if Figure 7 As shown in (d), when the imaging sensor 512 of the imaging device 1 is tilted (rotated) from the horizontal plane around the optical axis OA of the lens 511 by an angle ξ, the movement amounts Δx and Δy represented by expressions (7) and (8) can be compensated by expressions (9) and (10), respectively.

[0089] Δx=x×cos(γ+ξ)+y×sin(γ+ξ) (9)

[0090] Δy=x×sin(γ+ξ)+y×cos(γ+ξ) (10)

[0091] As described above, the imaging device 1 can calculate the movement amounts Δx and Δy and the rotation angle α of the celestial body by using the latitude ε detected by the positioning signal receiver 509, the azimuth angle A detected by the geomagnetic sensor 516, the elevation angle h and the rotation angle ξ detected by the attitude sensor 517, and the focal length f detected by the focal length detector 511a. Then, the imaging device 1 performs exposure while performing parallel motion control and rotational motion control on the imaging sensor 512 based on the calculated movement amounts Δx and Δy and the rotation angle α according to the movement of the celestial body using the driving unit 513, thereby achieving tracking shooting of the celestial body. In this case, the attitude of the imaging device 1 can be fixed.

[0092] On the other hand, as described above, the movable range of the imaging sensor 512 achieved by the driving unit 513 has mechanical limitations. Due to the mechanical limitations, the exposure time is also limited. Assuming that in the mechanical limitations, the mechanical limit value in the X direction is Lx, the mechanical limit value in the Y direction is Ly, and the mechanical limit value of the rotation is Lα, the time Tlimit to reach these limit values ​​can be calculated by using the mechanical limit values ​​Lx, Ly and Lα and expressions (5), (9) and (10). Assuming that the movement amounts Δx and Δy obtained in this case and the time Tlimit of the rotation angle α are Tlimit(Δx), Tlimit(Δy) and Tlimit(α) respectively, the minimum value of the three times Tlimit(Δx), Tlimit(Δy) and Tlimit(α) is the maximum exposure time of the target celestial body.

[0093] Configuration and operation of imaging device functional blocks

[0094] Fig.11 is a schematic diagram showing an example of a functional block configuration of an imaging device according to the embodiment. Fig.12 1 is a schematic diagram for explaining an operation of obtaining a maximum exposure time of another area by interpolating the maximum exposure time of sampling points within a frame in the imaging device according to the embodiment. Fig.13 1 is a schematic diagram showing an example of a display mode and a framing operation of a maximum exposure time within a frame of an imaging device according to an embodiment. Fig.11 and Fig.13 The configuration and operation of the functional blocks of the imaging device 1 according to the present embodiment are described.

[0095] like Fig.11 As shown, the imaging device 1 includes a first acquisition module 101 , a second acquisition module 102 , a motion amount calculation module 103 , an exposure time calculation module 104 , a display control module 105 , a drive control module 106 , a setting module 107 and a storage unit 108 .

[0096] The first acquisition module 101 is a processing module configured to acquire a captured image captured by the imaging sensor 512 and image-processed by the image processing unit 514. The first acquisition module 101 outputs the acquired captured image to the display control module 105.

[0097] The second acquisition module 102 is a processing module configured to acquire at least physical quantities related to the position and attitude of the imaging device 1, which are detected by various sensors (detection units). Specifically, the second acquisition module 102 acquires the latitude ε detected by the positioning signal receiver 509, the azimuth A detected by the geomagnetic sensor 516, the elevation angle h and the rotation angle ξ detected by the attitude sensor 517, and the focal length f detected by the focal length detector 511a. The second acquisition module 102 outputs the acquired physical quantities to the motion amount calculation module 103.

[0098] The motion amount calculation module 103 is a processing module that uses the latitude ε, azimuth angle A, elevation angle h, rotation angle ξ and focal length f acquired by the second acquisition module 102 to calculate the motion amount of each point (e.g., Fig.12 The motion amount calculation module 103 outputs the calculated motion amounts Δx, Δy and rotation angle α to the exposure time calculation module 104 and the drive control module 106. It should be noted that the motion amount calculation module 103 corresponds to the "first calculation module".

[0099] The exposure time calculation module 104 is a processing module configured to calculate the maximum exposure time of each point (each celestial body) included in the frame photographed by the imaging sensor 512 based on the mechanical limitation of the movable range of the imaging sensor 512 by using the movement amounts Δx and Δy calculated by the movement amount calculation module 103 and the rotation angle α. Specifically, Fig.12As shown, the exposure time calculation module 104 first calculates the maximum exposure time of the corresponding sampling point SP by using the movement amount Δx and Δy corresponding to each sampling point SP arranged in a grid pattern in the frame F3 photographed by the imaging sensor 512 and the rotation angle α. Then, the exposure time calculation module 104 performs interpolation processing using the maximum exposure time of the sampling point SP, and then calculates the maximum exposure time of the points other than the sampling point SP in the frame F3. In other words, the exposure time calculation module 104 does not obtain the maximum exposure time of all points included in the frame F3 by the movement amount Δx, Δy and rotation angle α corresponding to all points. Instead, the exposure time calculation module 104 obtains the maximum exposure time (first maximum exposure time) of each sampling point SP only according to the movement amount Δx and Δy of the corresponding sampling point SP and the rotation angle α, and calculates the maximum exposure time (second maximum exposure time) corresponding to each other point by interpolation processing. Therefore, the calculation load of the movement amount calculation module 103 and the exposure time calculation module 104 is reduced. The exposure time calculation module 104 outputs the calculated maximum exposure time to the display control module 105 and the drive control module 106. It should be noted that the exposure time calculation module 104 corresponds to a “second calculation module.” Furthermore, the sampling points SP correspond to a “predetermined plurality of points.” Furthermore, the movement amount calculation module 103 and the exposure time calculation module 104 correspond to a “calculation module.”

[0100] The display control module 105 is a processing module configured to control the display operation of the display 506. When the user performs framing by changing the imaging direction of the imaging device 1, the display control module 105 causes the display 506 to display the captured image acquired by the first acquisition module 101 and the information on the maximum exposure time calculated by the exposure time calculation module 104 to superimpose the information on the captured image. Fig.13 As shown in (a), assuming that there is an area with a maximum exposure time of "10 seconds", an area with a maximum exposure time of "20 seconds", and an area with a maximum exposure time of "30 seconds", the display control module 105 displays the boundaries between the areas corresponding to the predetermined ranges of the maximum exposure time and displays the maximum exposure time representing the corresponding ranges (for example, Fig.13(a) "10 seconds", "20 seconds", and "30 seconds") in order to be able to identify the distribution of maximum exposure times in the frame (captured image). In this case, for example, the area of ​​"10 seconds" may indicate an area where the maximum exposure time is not greater than 10 seconds, the area of ​​"20 seconds" may indicate an area where the maximum exposure time is greater than 10 seconds and less than 20 seconds, and the area of ​​"30 seconds" may indicate an area where the maximum exposure time is greater than 20 seconds and less than 30 seconds. Therefore, the user can identify the distribution of the maximum exposure time of a point (celestial body) in the frame determined by the imaging direction of the imaging device 1. In this case, when the exposure time (specified exposure time) set by the setting module 107 is 15 seconds, for example, because tracking shooting cannot be performed on the "10 seconds" area using exposure with the specified exposure time, the user can adjust the exposure direction by moving toward Fig.13 The arrow shown in (b) performs framing (changing the imaging direction of the imaging device 1) to remove the area of ​​"10 seconds" from the frame, thereby determining a frame in which tracking shooting can be performed by exposure using a designated exposure time.

[0101] It should be noted that the information about the maximum exposure time superimposed on the captured image is not limited to Fig.13 The information shown is displayed. For example, the display control module 105 may display the maximum exposure time corresponding to the boundary between the areas as superimposed on the boundary. In this case, for example, when the maximum exposure time superimposed on the displayed boundary is "20 seconds", it can be understood that one side of the boundary is an area where the maximum exposure time is less than 20 seconds, and the other side is an area where the maximum exposure time is greater than 20 seconds. Alternatively, the display control module 105 may give transparency to a grayscale image represented by a hue of a specific color according to the size of the maximum exposure time to superimpose the grayscale image on the captured image. In this case, the display control module 105 may switch the image to be displayed on the display 506 between the captured image and the grayscale image according to the operation of the touch panel 505. Therefore, the distribution of the maximum exposure time can be intuitively grasped according to the hue of the specific color, so that appropriate framing can be easily performed.

[0102] The drive control module 106 is a processing module configured to movably control the drive unit 513 via the imaging control unit 515 to perform parallel motion control in a direction orthogonal to the optical axis OA of the imaging sensor 512 installed in the drive unit 513 and rotational motion control centered on an axis parallel to the optical axis OA. In addition, the drive control module 106 controls the imaging operation of the imaging sensor 512 via the image processing unit 514. In addition, when a shooting operation related to tracking shooting is started, the drive control module 106 performs parallel motion control and rotational motion control on the imaging sensor 512 by using the drive unit 513 according to the motion of the celestial body based on the motion amounts Δx and Δy and the rotation angle α calculated by the motion amount calculation module 103, and performs exposure according to the specified exposure time set by the setting module 107. In other words, the drive control module 106 performs control according to the movement of the celestial body based on the movement amounts Δx and Δy and the rotation angle α to change the positional relationship between the imaging sensor 512 and the lens 511 so that the position of the celestial body as the subject included in the captured image remains unchanged on the imaging surface 512a.

[0103] The setting module 107 is a processing module configured to set the operation mode of the imaging device 1 and various types of information according to the operation of the touch panel 505. For example, the setting module 107 sets the exposure time used by the imaging sensor 512 and causes the storage unit 108 to store the set exposure time as the specified exposure time. In addition, the setting module 107 sets the tracking shooting mode or the normal shooting mode as the operation mode. The tracking shooting mode is a mode in which shooting is performed by exposure using the set specified exposure time while the imaging sensor 512 is moved to track the movement of the celestial body as described above. The normal shooting mode is a mode in which shooting is performed by exposing using the specified exposure time in a state in which the imaging sensor 512 is fixed. The setting module 107 causes the storage unit 108 to store the set operation mode. In addition, the setting module 107 outputs the set specified exposure time to the drive control module 106.

[0104] like Fig.11 The first acquisition module 101, the second acquisition module 102, the motion amount calculation module 103, the exposure time calculation module 104, the display control module 105, the drive control module 106 and the setting module 107 of the imaging device 1 are connected by Figure 1 It should be noted that at least one of the first acquisition module 101, the second acquisition module 102, the motion amount calculation module 103, the exposure time calculation module 104, the display control module 105, the drive control module 106 and the setting module 107 can be implemented by hardware such as an integrated circuit.

[0105] The storage unit 108 is a unit configured to store a program of the imaging device 1, various types of setting information set by the setting module 107, and the like. For example, the storage unit 108 is composed of Figure 1 The RAM 503 or flash memory 504 implementation is shown.

[0106] It should be noted that Fig.11 The processing modules of the imaging device 1 shown in FIG. 1 conceptually indicate functions and are therefore not limited to such configurations. For example, Fig.11 Multiple independent processing modules in the process can be configured as one processing module. On the other hand, by dividing the functions of one processing module into two or more, Fig.11 The one processing module shown in is configured as multiple processing modules.

[0107] Fig.14 : is a flowchart showing an example of the flow of the maximum exposure time display process and the tracking shooting process of the imaging device according to the present embodiment. Fig.15 1 is a schematic diagram showing an example of the operation of a display area that cannot be compensated within a frame captured by an imaging device according to an embodiment. Fig.14 and Fig.15 The flow of the maximum exposure time display process and the tracking shooting process of the imaging device 1 according to the present embodiment is described. It should be noted that the operation mode is considered to be set in advance by the setting module 107 as the tracking shooting mode.

[0108] Operation of step S11

[0109] The drive control module 106 of the imaging device 1 performs initialization processing on the drive unit 513 via the image processing unit 514. For example, the drive control module 106 returns the position of the imaging sensor 512 to the original position by performing the initialization processing on the drive unit 513. Then, the process proceeds to step S12.

[0110] Operation of step S12

[0111] The first acquisition module 101 of the imaging device 1 acquires a captured image photographed by the imaging sensor 512 and on which image processing is performed by the image processing unit 514. In this case, the captured image photographed by the imaging sensor 512 may be stored in the storage unit 108, and the first acquisition module 101 may acquire the captured image stored in the storage unit 108. The first acquisition module 101 outputs the acquired captured image to the display control module 105. Then, the process proceeds to step S13.

[0112] Operation of step S13

[0113] The second acquisition module 102 of the imaging device 1 acquires the latitude ε detected by the positioning signal receiver 509, the azimuth A detected by the geomagnetic sensor 516, the elevation angle h and the rotation angle ξ detected by the attitude sensor 517, and the focal length f detected by the focal length detector 511a. The second acquisition module 102 outputs the acquired physical quantity to the motion amount calculation module 103. Then, the process proceeds to step S14.

[0114] Operation of Step S14

[0115] The motion amount calculation module 103 of the imaging device 1 calculates the motion amounts Δx and Δy and the rotation angle α of each sampling point SP included in the frame photographed by the imaging sensor 512 by the above expressions (5), (9) and (10) using the latitude ε, azimuth angle A, elevation angle h, rotation angle ξ and focal length f acquired by the second acquisition module 102. The motion amount calculation module 103 outputs the calculated motion amounts Δx and Δy and the rotation angle α to the exposure time calculation module 104.

[0116] Next, by using the movement amounts Δx and Δy corresponding to each sampling point SP arranged in a grid pattern in the frame captured by the imaging sensor 512 and the rotation angle α, the exposure time calculation module 104 of the imaging device 1 calculates the maximum exposure time of the corresponding sampling point SP. Then, the exposure time calculation module 104 calculates the maximum exposure time of the points other than the sampling point SP in the frame through interpolation processing using the maximum exposure time of the sampling point SP. The exposure time calculation module 104 outputs the calculated maximum exposure time to the display control module 105. Then, the process proceeds to step S15.

[0117] Operation of step S15

[0118] The display control module 105 of the imaging device 1 causes the display 506 to display the captured image acquired by the first acquisition module 101 and the information related to the maximum exposure time calculated by the exposure time calculation module 104 to superimpose the information on the captured image. Therefore, the user can recognize the distribution of the maximum exposure time of the point (celestial body) in the frame determined by the imaging direction of the imaging device 1. Then, the process proceeds to step S16.

[0119] Operation of step S16

[0120] The user checks the captured image displayed by the display 506 and the information about the maximum exposure time superimposed on the captured image, and changes the imaging direction of the imaging device 1 to adjust the framing to the expected distribution of the maximum exposure time. Then, in response to the operation of the touch panel 505 (step S16: Yes), when shooting starts in the tracking shooting mode, the drive control module 106 sets the state of the imaging sensor 512 to the exposure state, and the process proceeds to step S17. On the other hand, when the user continues to adjust the framing by changing the imaging direction of the imaging device 1 (step S16: No), the process returns to step S12.

[0121] Operation of step S17

[0122] The motion amount calculation module 103 calculates the motion amounts Δx and Δy and the rotation angle α of each sampling point SP contained in the frame photographed by the imaging sensor 512 by the above-mentioned expressions (5), (9) and (10) by using the latitude ε, azimuth angle A, elevation angle h, rotation angle ξ and focal length f acquired by the second acquisition module 102. The motion amount calculation module 103 outputs the calculated motion amounts Δx and Δy and the rotation angle α to the exposure time calculation module 104 and the drive control module 106. Then, the process proceeds to step S18.

[0123] Operation of step S18

[0124] The drive control module 106 of the imaging device 1 performs parallel motion control and rotational motion control on the imaging sensor 512 according to the motion of the celestial body through the drive unit 513 based on the motion amounts Δx and Δy and the rotation angle α calculated by the motion amount calculation module 103. Then, the process proceeds to step S19.

[0125] Operation of Step S19

[0126] When tracking shooting is started and the designated exposure time has elapsed (step S19: Yes), the process proceeds to step S20. When the designated exposure time has not elapsed (step S19: No), the process returns to step S16. It should be noted that the drive control module 106 may terminate tracking shooting when the amount of movement of the imaging sensor 512 reaches a mechanical limit before the designated exposure time has elapsed.

[0127] Operation of step S20

[0128] The drive control module 106 terminates the tracking photography. Then, the process proceeds to step S21.

[0129] Operation of step S21

[0130] The first acquisition module 101 acquires a captured image photographed by the imaging sensor 512 in a state where the imaging sensor is exposed for a specified exposure time. Then, the process proceeds to step S22.

[0131] Operation of step S22

[0132] The first acquisition module 101 stores the acquired captured image in the storage unit 108, and outputs the captured image to the display control module 105. The display control module 105 causes the display 506 to display the captured image acquired by the first acquisition module 101. Therefore, the user can check the image on the display 506 in which the celestial bodies (stars) in the starry sky are captured as point images in the tracking shooting mode.

[0133] The maximum exposure time display process and the tracking shooting process of the imaging device 1 are performed through the flow of steps S11 to S22 .

[0134] In addition, in step S15, if Fig.15 As shown, for example, when the display control module 105 superimposes and displays the captured image and the information related to the maximum exposure time of the frame F4 on the display 506, if an area in which tracking photography of the designated exposure time set by the setting module 107 cannot be performed is included in the frame F4, the display control module 105 can perform a specific color display that is transparent to the area to highlight the area. For example, because tracking photography of 11 seconds cannot be performed on the "10 seconds" area in the frame F4 when the setting module 107 sets 11 seconds as the designated exposure time, the display control module 105 performs a specific color display that is transparent to the "10 seconds" area, as shown in FIG. Fig.15 In this case, Fig.15 As shown, for example, the user clicks the displayed portion of "10 seconds" in the "10 seconds" area, and thus the setting module 107 can set the designated exposure time to the minimum value of the maximum exposure time in the "10 seconds" area. Therefore, the user can not only perform framing to enable tracking shooting within the set designated exposure time, but also set the designated exposure time to enable tracking shooting within a specific frame.

[0135] The imaging sensor 512 is physically translated and rotated by the driving control of the driving unit 513, thereby realizing the above-mentioned tracking shooting operation, but the present embodiment is not limited thereto. For example, a combination of an image blur compensation device and a driving unit 513 that rotates the imaging sensor 512 can also capture a celestial body as a point image by tracking and shooting the celestial body. The image blur compensation device includes an image blur compensation lens in the lens 511, which moves the position of the subject on the imaging sensor 512. Even in this case, the driving control module 106 performs control according to the movement of the celestial body based on the movement amounts Δx and Δy and the rotation angle α to change the positional relationship between the imaging sensor 512 and the lens 511, so that the position of the celestial body as the subject contained in the captured image on the imaging surface 512a remains unchanged.

[0136] Operation in normal shooting mode

[0137] Fig.16 1 is a schematic diagram showing an example of a display mode of the length of the starlight trail that can be captured in a frame captured by the imaging device according to the embodiment. Fig.16 The operation of the imaging device 1 of the present embodiment in the normal shooting mode is described.

[0138] The first acquisition module 101 acquires a captured image photographed by the imaging sensor 512 and on which image processing is performed by the image processing unit 514. The first acquisition module 101 outputs the acquired captured image to the display control module 105.

[0139] The second acquisition module 102 acquires the latitude ε detected by the positioning signal receiver 509, the azimuth A detected by the geomagnetic sensor 516, the elevation h and the rotation angle ξ detected by the attitude sensor 517, and the focal length f detected by the focal length detector 511a. The second acquisition module 102 outputs the acquired physical quantities to the motion amount calculation module 103.

[0140] The motion amount calculation module 103 calculates the motion amounts Δx and Δy and the rotation angle α of the central celestial body contained in the frame captured by the imaging sensor 512 by using the latitude ε, azimuth angle A, elevation angle h, rotation angle ξ, and focal length f acquired by the second acquisition module 102 through the above expressions (5), (9), and (10). In addition, based on the calculated motion amounts Δx and Δy and the rotation angle α, the motion amount calculation module 103 calculates the length of the starlight trail to be drawn when the exposure is performed within the specified exposure time set by the setting module 107. It should be noted that the motion amounts Δx and Δy and the rotation angle α calculated by the motion amount calculation module 103 are not limited to the motion amounts Δy and the rotation angle α of the central celestial body in the frame (captured image). The motion amount calculation module 103 outputs the calculated starlight trail length to the display control module 105.

[0141] The display control module 105 causes the display 506 to display the captured image acquired by the first acquisition module 101, and to display the starlight trail length calculated by the motion amount calculation module 103 in a predetermined area of ​​the captured image. For example, when the frame F5 is captured by the imaging sensor 512, as shown in FIG. Fig.16 As shown, the display control module 105 causes the display 506 to display the captured image of the frame F5, and displays the starlight trail length of the central celestial body in the frame F5 calculated by the motion amount calculation module 103 in the display area AR5. Fig.16 As shown, when the imaging sensor 512 captures frame F6 framed in an area closer to the north pole of the celestial body than frame F5, the display control module 105 causes the display 506 to display the captured image of frame F6, and displays the length of the starlight trail of the central celestial body in frame F6 calculated by the motion calculation module 103 in the display area AR6 (shorter than the starlight trail length of frame F5).

[0142] In this way, when photographing the light trail of a celestial body (star) by performing exposure for a designated exposure time in the normal photographing mode, the user can check in advance how long the length of the starlight trail to be photographed is in the imaging direction in which framing is performed.

[0143] As described above, in the imaging device 1 according to the present embodiment: the first acquisition module 101 acquires a captured image of a celestial body photographed by the imaging sensor 512; the second acquisition module 102 acquires physical quantities related to at least the position and attitude of the imaging device 1 detected by a plurality of sensors; the motion amount calculation module 103 calculates the motion amounts Δx and Δy and the rotation angle α of the celestial body contained in the image photographed on the imaging surface 512a of the imaging sensor 512 based on the physical quantities acquired by the second acquisition module 102; the exposure time calculation module 104 calculates the maximum exposure time that can track the celestial body contained in the captured image according to the change in the positional relationship when the imaging sensor 512 performs exposure based on the motion amounts Δx and Δy, the rotation angle α, and the limit of the change range of the positional relationship between the imaging sensor 512 and the lens 511; the display control module 105 causes the display 506 to display the captured image and the information about the maximum exposure time so as to superimpose the information on the captured image. In this case, for example, the display control module 105 displays the boundary between the regions corresponding to the predetermined ranges of the maximum exposure time and the maximum exposure time representing the respective predetermined ranges as the information related to the maximum exposure time. Therefore, the user can check the maximum exposure time, can perform framing for a desired maximum exposure time, and can photograph a celestial body as a point image within the user's intentional exposure time.

[0144] The drive control module 106 changes the positional relationship between the imaging sensor 512 and the lens 511 based on the movement amounts Δx and Δy and the rotation angle α so that the position of each celestial body included in the captured image on the imaging surface 512a does not change. For example, based on the movement amounts Δx and Δy and the rotation angle α, the drive control module 106 performs parallel motion control on the imaging sensor 512 in a direction orthogonal to the optical axis OA of the lens 511, and performs rotational motion control on the imaging sensor 512 around an axis parallel to the optical axis OA. Therefore, compensation for the diurnal motion of the celestial body can be performed, and the celestial body can be photographed as a point image.

[0145] Furthermore, in the maximum exposure time in the captured image, the exposure time calculation module 104 calculates a first maximum exposure time corresponding to a predetermined sampling point SP in the captured image, and calculates a second maximum exposure time of an area other than the sampling point SP in the captured image by using an interpolation process for the first maximum exposure time corresponding to the sampling point SP. Therefore, the calculation load can be reduced.

[0146] It should be noted that each function of the above-mentioned embodiments can be implemented by one or more processing circuits. Here, "processing circuit" includes: a processor programmed to perform functions by software, similar to a processor implemented by an electronic circuit; and devices such as ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array) and conventional circuit modules, which are designed to perform the above-mentioned functions.

[0147] The program executed by the imaging device 1 according to the above-described embodiment may be configured to be provided by being incorporated in a ROM or the like in advance.

[0148] In addition, the program executed by the imaging device 1 according to the above-mentioned embodiment can be configured to be provided as a computer program product by recording it in a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a floppy disk (FD), a CD-R (Compact Disc Recordable) and a DVD (Digital Versatile Disk) in an installable or executable file format.

[0149] In addition, the program executed by the imaging device 1 according to the above-mentioned embodiment can be configured to be provided by being stored on a computer connected to a network (such as the Internet) and downloaded through the network. In addition, the program executed by the imaging device 1 according to the above-mentioned embodiment can be configured to be provided or distributed through a network (such as the Internet).

[0150] In addition, the program executed by the imaging device 1 according to the above embodiment has a module configuration including the above functional parts. From the perspective of actual hardware, the CPU (processor) reads and executes the program from the ROM, so the above functional parts are loaded on the main memory and generated on the main memory.

[0151] [Explanation of letters or numbers]

[0152] 1 Imaging equipment

[0153] 101 First Acquisition Module

[0154] 102 Second acquisition module

[0155] 103 Exercise volume calculation module

[0156] 104 Exposure time calculation module

[0157] 105 Display Control Module

[0158] 106 Drive control module

[0159] 107 Setting Module

[0160] 108 storage units

[0161] 501 CPU

[0162] 502 ROM

[0163] 503 RAM

[0164] 504 Flash

[0165] 505 Touch Panel

[0166] 506 Display

[0167] 507 External device connection I / F

[0168] 508 Communication Circuit

[0169] 508a Antenna

[0170] 509 Positioning signal receiver

[0171] 511 Lens

[0172] 511a Focus Detector

[0173] 512 Imaging Sensor

[0174] 512a Imaging surface

[0175] 513 Drive Unit

[0176] 514 Image Processing Unit

[0177] 515 Imaging Control Unit

[0178] 516 Geomagnetic Sensor

[0179] 517 Attitude Sensor

[0180] 518 Acceleration Sensor

[0181] 520 bus

[0182] A azimuth

[0183] AR5, AR6 display area

[0184] C Center

[0185] CE Celestial Equator

[0186] CS Sky Sphere

[0187] E equator

[0188] ER Earth

[0189] F1-F6 Frames

[0190] h Elevation angle

[0191] H Hour angle

[0192] N points

[0193] NCP Celestial North Pole

[0194] NP Arctic

[0195] O Shooting point

[0196] OA optical axis

[0197] OB Track

[0198] S-body

[0199] SP sampling point

[0200] Z Zenith

[0201] Gamma angle

[0202] δ Declination

[0203] ε Latitude

[0204] θ Angle

[0205] ξ Rotation angle

Claims

1. An imaging device, comprising: a first acquisition module, the first acquisition module being configured to acquire a captured image of a celestial body taken by an imaging unit; a second acquisition module, the second acquisition module being configured to acquire physical quantities at least related to the position and posture of the imaging device detected by a plurality of detectors; a calculation module configured to calculate, based on the physical quantity of the imaging device, a movement amount and a rotation angle of a celestial body contained in the captured image, and calculate a maximum exposure time for tracking the celestial body contained in the captured image; and a display control module configured to cause a display unit to display a captured image on which information related to the maximum exposure time is superimposed, The display control module is configured to display the boundary between the areas corresponding to the predetermined range of the maximum exposure time and the maximum exposure time representing the corresponding predetermined range as the information.

2. The imaging device according to claim 1, further comprising: A drive control module is configured to change the positional relationship based on the movement amount and the rotation angle so that the position of each of the celestial bodies included in the captured image on the imaging surface does not change.

3. The imaging device according to claim 2, wherein: The imaging device includes an optical system, and the driving control module is configured to perform parallel motion control on the imaging unit in a direction orthogonal to the optical axis of the optical system based on the movement amount and the rotation angle, and to perform rotational motion control on the imaging unit around an axis parallel to the optical axis to change the positional relationship.

4. The imaging device according to claim 1, wherein The imaging device includes an optical system, and the physical quantity includes any one of the following items: the latitude of the imaging device, the azimuth of the imaging direction of the imaging device, the elevation angle between the imaging direction and the horizontal plane, the rotation angle centered on the optical axis of the imaging unit, and the focal length of the optical system.

5. The imaging device according to claim 1, wherein The display control module is configured to highlight a region including the celestial object contained in the captured image.

6. The imaging device according to claim 5, further comprising: A setting module is configured to set a minimum value of the maximum exposure time of the celestial body contained in the area as a designated exposure time in response to an operation on the area highlighted by the operation unit.

7. The imaging device according to claim 1, wherein: The calculation module is configured to: calculate, among the maximum exposure times in the captured image, a first maximum exposure time corresponding to a predetermined plurality of points in the captured image; And by performing interpolation processing on the first maximum exposure times corresponding to the plurality of points, a second maximum exposure time of an area other than the plurality of points in the captured image is calculated.

8. The imaging device according to claim 1, wherein The calculation module is configured to calculate the length of the starlight trail that will be drawn when the celestial body is exposed to the imaging unit according to the calculated motion amount and rotation angle, and The display control module is configured to cause the display unit to display the captured image and display the starlight trail length in a predetermined area on the captured image.

9. The imaging device according to claim 8, further comprising: A setting module is configured to set the designated exposure time in response to an operation of an operation unit.

10. The imaging device according to claim 1, wherein The calculation module is configured to calculate the maximum exposure time based on a limit of a variation range of a positional relationship between the imaging unit and an optical system that collects light on an imaging surface of the imaging unit.

11. An image processing method for an imaging device, the method comprising: acquiring a captured image of a celestial body taken by an imaging unit; Acquire physical quantities at least related to the position and posture of the imaging device detected by a plurality of detectors; calculating, based on the physical quantity of the imaging device, the amount of motion and the rotation angle of the celestial body contained in the captured image, and calculating the maximum exposure time during which the celestial body contained in the captured image is tracked; and The method of causing a display unit to display a captured image, wherein information related to the maximum exposure time is superimposed on the captured image, comprises: The boundary between the areas corresponding to the predetermined range of the maximum exposure time and the maximum exposure time representing the corresponding predetermined range are displayed as the information.

12. The method according to claim 11, wherein: The calculating includes calculating the maximum exposure time based on a limit of a variation range of a positional relationship between the imaging unit and an optical system that collects light on an imaging surface of the imaging unit.

13. A program product, the program product causing a computer to execute: acquiring a captured image of a celestial body taken by an imaging unit; Acquire physical quantities at least related to the position and posture of the imaging device detected by the plurality of detectors; calculating, based on the physical quantity of the imaging device, the amount of motion and the rotation angle of the celestial body contained in the captured image, and calculating the maximum exposure time during which the celestial body contained in the captured image is tracked; and The method of causing a display unit to display a captured image, wherein information related to the maximum exposure time is superimposed on the captured image, comprises: The boundary between the areas corresponding to the predetermined range of the maximum exposure time and the maximum exposure time representing the corresponding predetermined range are displayed as the information.

14. The program product according to claim 13, wherein: Calculating a maximum exposure time during which the celestial body included in the captured image is tracked includes calculating the maximum exposure time based on a limit of a variation range of a positional relationship between the imaging unit and an optical system that focuses light on an imaging surface of the imaging unit.

Images