Imaging control method, imaging control device, and program

Abstract

The present disclosure relates to an imaging control method, an imaging control device, and a program that make it possible to prevent imaging failures. An imaging control method according to the present disclosure includes: acquiring the movement speed of a moving body; acquiring the separation between a subject in a captured image to be captured by a camera mounted on the moving body, and the moving body; and calculating the shutter speed of the camera on the basis of the movement speed and the separation. The present disclosure can be applied to integrated circuits such as SoCs that control imaging in drones.

Description

Photographing control method, photographing control device, and program

[0001] The present disclosure relates to an imaging control method, an imaging control device, and a program, and more particularly to an imaging control method, an imaging control device, and a program that can prevent imaging failures.

[0002] A conventional photography method known as panning, in which a camera is moved to follow a moving subject, is known. Patent Document 1 discloses an imaging device that reduces the difficulty of panning and allows the photographer to concentrate on selecting a composition by determining the shutter speed based on the angular velocity when the optical axis of the photographing lens is moved left and right and the focal length of the photographing lens.

[0003] On the other hand, drones equipped with RGB cameras have become popular in recent years, and are being used not only for aerial photography but also for industrial purposes such as inspection and surveying.

[0004] JP 2015-102774 A

[0005] When taking pictures using a camera mounted on a moving object, it is easy for mistakes to occur, such as the image being blurred as the moving object moves.

[0006] The present disclosure has been made in light of such circumstances, and is intended to prevent photographing failures.

[0007] The photography control method disclosed herein is a photography control method that includes acquiring the movement speed of a moving body, acquiring the distance between the moving body and a subject of an image captured by a camera mounted on the moving body, and calculating the shutter speed of the camera based on the movement speed and the distance.

[0008] The photography control device disclosed herein is a photography control device that includes a movement speed acquisition unit that acquires the movement speed of a moving body, a separation distance acquisition unit that acquires the separation distance between the moving body and a subject of an image captured by a camera mounted on the moving body, and a shutter speed calculation unit that calculates the shutter speed of the camera based on the movement speed and the separation distance.

[0009] The program disclosed herein is a program for causing a computer to execute a process including acquiring the movement speed of a moving body, acquiring the distance between the moving body and a subject of an image captured by a camera mounted on the moving body, and calculating the shutter speed of the camera based on the movement speed and the distance.

[0010] In the present disclosure, the movement speed of a moving body is acquired, the distance between the subject of an image captured by a camera mounted on the moving body and the moving body is acquired, and the shutter speed of the camera is calculated based on the movement speed and the distance.

[0011] FIG. 1 is a diagram illustrating an appropriate shutter speed for a flight speed. FIG. 2 is a diagram illustrating an appropriate shutter speed for a separation distance. FIG. 3 is a diagram illustrating an example configuration of an imaging system to which the technology according to the present disclosure is applied. FIG. 4 is a diagram illustrating another example configuration of an imaging system to which the technology according to the present disclosure is applied. FIG. 5 is a block diagram illustrating an example functional configuration of an optimal control calculation unit of a first embodiment. FIG. 6 is a flowchart illustrating the flow of imaging processing by a moving body. FIG. 7 is a flowchart illustrating details of optimal control calculation processing. FIG. 8 is a block diagram illustrating an example functional configuration of an optimal control calculation unit of a second embodiment. FIG. 9 is a flowchart illustrating the flow of imaging processing by a moving body. FIG. 10 is a flowchart illustrating details of optimal control calculation processing. FIG. 11 is a diagram illustrating setting of a shutter speed for each step. FIG. 12 is a diagram illustrating an example of a shutter speed for each step. FIG. 13 is a diagram illustrating setting of a shutter speed according to an application. FIG. 14 is a block diagram illustrating an example configuration of computer hardware.

[0012] Modes for carrying out the present disclosure (hereinafter referred to as embodiments) will be described below in the following order.

[0013] 1. Background and specific examples of photography failures 2. Overview of the technology according to the present disclosure 3. Configuration example of a photography system 4. First embodiment (calculation of appropriate shutter speed) 5. Second embodiment (restrictions when photography cannot be performed with appropriate exposure) 6. Application example 7. Configuration example of computer hardware

[0014] <1. Background and Specific Examples of Photography Failures> (Background) In recent years, drones equipped with RGB cameras have become widespread, not only for aerial photography but also for industrial applications such as inspection and surveying. However, drone operators who are not familiar with cameras do not know what settings to use to obtain the intended images. Therefore, when such operators operate drone-mounted cameras, photography failures are more likely to occur, resulting in reduced work efficiency and photographic results that do not meet expectations.

[0015] (Specific Examples of Mistakes in Photography) Here, specific examples of mistakes in photography when inspecting a structure will be described.

[0016] (A) General camera settings: When flying a drone equipped with a commercially available SLR camera, it is often not possible to perform detailed settings in the air via the system, and if the settings are not correct, the drone must be landed. Drone operators may not be familiar with cameras and may not know what settings will result in the desired image (even if they try various things, they have to land the drone and check the image data each time, which is cumbersome).

[0017] (B) Focus: The focus is not set to the intended position (the focus is set to the foreground rather than the subject, or to the background). While you want to focus on the entire screen, the camera's depth of field is shallow and the in-focus range is narrow (the aperture is opened too much).

[0018] (C) Exposure: There are sunny and shady areas on one image plane, and the exposure is not correct. White subjects with few distinctive features are overexposed.

[0019] (D) White balance: When shooting in auto white balance mode, the color of the image will vary depending on the location.

[0020] (E) Shaking: If the camera moves due to the drone's fast flight speed, vibration of the aircraft or gimbal, etc., and the shutter speed is slow, the image will be blurred and unclear.

[0021] (F) Required resolution (resolution) - When setting the image resolution (the range captured per pixel) to find cracks or scratches in a structure, it is necessary to take the image at an appropriate distance based on the image sensor resolution and lens focal length. If this is not met, sufficient resolution cannot be guaranteed.

[0022] 2. Overview of the Technology According to the Present Disclosure The present disclosure proposes a technology for solving "(E) blurring," one of the specific examples of failures that may occur in photographing when inspecting a structure, as described above.

[0023] During inspections, in order to obtain the necessary image "resolution," the drone must fly at an appropriate "separation distance," fly at a constant "flight speed" in consideration of operational efficiency, and release the shutter at a constant speed to obtain the necessary images. It is possible to hover and take photos at each inspection point, but this takes time. It is desirable to have as fast a shutter speed as possible.

[0024] For inspection purposes, it is better to increase the depth of field without opening the aperture too much, as this will widen the range in focus. On the other hand, if the aperture is closed too much, aperture blur will occur, so it is necessary to set the aperture appropriately (for example, around F5.6 to F8).

[0025] Setting the ISO sensitivity is important to ensure proper exposure by making the shutter speed as fast as possible and fixing the aperture constant. The lower the ISO sensitivity value, the less noise an image will have, so for example, in a bright environment, the ISO sensitivity is fixed at 100 and the exposure is adjusted by the shutter speed. If the shutter speed reaches the limit of the camera's performance, the image will be overexposed (too bright). In dark environments such as dark places, the shutter speed cannot be made slower than a certain value due to the relationship with flight speed, so the ISO sensitivity is increased.

[0026] To obtain the appropriate shutter speed to prevent blurring of the image, the relationship between the "pixel size" calculated from the size and resolution of the camera's image sensor, the "lens focal length," the "separation distance" between the subject and the drone, and the "flight speed" is important.

[0027] FIG. 1 is a diagram for explaining the appropriate shutter speed for the flight speed.

[0028] Figure 1 shows a graph of the shutter speed denominator (xxx) calculated as 1 / [(focal length * flight speed) / (required pixel size * separation distance)] for a flight speed of 0 to 2 m / s at a fixed separation distance. If the value xxx for the flight speed is in the gray area in Figure 1, it is an appropriate shutter speed that will not blur the image.

[0029] The "required pixel size" depends on the ground sample distance (GSD) of the image captured by the camera and represents the amount of blur that can be tolerated in the captured image (hereinafter referred to as "tolerable blur") in pixel size. The "required pixel size" is determined experimentally from the relationship between flight speed and shutter speed to obtain the highest resolution for a camera and lens combination. It does not need to be a specific value and varies depending on the conditions and user requirements. Figure 1 shows the shutter speed versus flight speed when a 1 mm crack, for example, is to be visually recognized at a separation distance of 4.2 m (GSD = 0.4 mm / pix) and a pixel size of 3.8 μm, and the "required pixel size" is set to the size of two pixels.

[0030] FIG. 2 is a diagram for explaining the appropriate shutter speed for the separation distance.

[0031] FIG. 2 shows the appropriate shutter speeds for the separation distances when the flight speed is constant at 0.1 m / s, 1 m / s, 2 m / s, 3 m / s, 4 m / s, and 5 m / s.

[0032] As shown in Figure 2, the higher the flight speed, the more likely the captured image is to be blurred, so the higher the flight speed, the faster the appropriate shutter speed. Also, when the separation distance (the distance from the drone to the subject) is large, the effect of blurring in the captured image is small, so the longer the separation distance, the slower the appropriate shutter speed can be, regardless of the flight speed.

[0033] In calculating the appropriate shutter speed, it is important to accurately measure the parameters of each element. Camera parameters can be obtained from the camera's specifications, etc. Flight speed can be obtained in real time if the drone uses GNSS (Global Navigation Satellite System) information. Separation distance can be obtained by installing a ranging sensor such as LiDAR (Light Detection and Ranging) on ​​the drone.

[0034] 3. Configuration Example of Imaging System FIG. 3 is a diagram showing a configuration example of an imaging system to which the technology according to the present disclosure is applied.

[0035] The imaging system shown in FIG. 3 is configured to include an input / output device 100 , a moving body 200 , and a payload 300 .

[0036] The input / output device 100 is a controller used by an operator (user) who operates the moving body 200, and is configured from a tablet terminal, a smartphone, a dedicated terminal such as a radio transmitter, or the like.

[0037] The input / output device 100 is configured to include a display 110 , a touch panel 120 , buttons 130 , and a stick 140 .

[0038] The display 110 displays the movement path of the moving body 200, the status of each part of the moving body 200 and the payload 300, images captured by a camera mounted on the payload 300, etc. The touch panel 120 is provided superimposed on the display 110 to provide a GUI (Graphical User Interface) operated by a user. The button 130 and the stick 140 are physical operation units provided on the housing of the input / output device 100. The button 130 is used to perform operations such as turning on / off each part of the moving body 200 and the payload 300. The stick 140 is used to perform operations for moving the moving body 200.

[0039] The mobile body 200 is a mobile device that can move according to operation information from the input / output device 100 or autonomously move based on preset route information. In the embodiment of the present disclosure, the mobile body 200 is described as a drone that can perform inspections, surveying, aerial photography, etc., but the mobile body 200 may also be a vehicle that can travel on the ground using tires or caterpillar tracks, a mobile robot that can travel on walls and ceilings, a disaster relief robot that can move in disaster sites where human access is difficult, etc.

[0040] The moving body 200 is configured to include a sensor unit 210 , a drive unit 220 , and a movement control unit 230 .

[0041] The sensor unit 210 is composed of a position information sensor capable of acquiring position information such as GNSS information. The sensor information acquired by the sensor unit 210 is supplied to the movement control unit 230. The drive unit 220 generates a driving force for moving the mobile body 200 under the control of the movement control unit 230. If the mobile body 200 is a drone, the drive unit 220 is composed of a motor that rotates a propeller, etc. The movement control unit 230 controls the movement of the mobile body 200 and also controls the operation of a camera and a gimbal mounted on the payload 300. If the mobile body 200 is a drone, the movement control unit 230 is composed of a flight controller, etc.

[0042] The payload 300 is a load carried on the moving body 200, and includes a camera, a gimbal, and the like.

[0043] The payload 300 is configured to include a gimbal 310 , an image capturing unit 320 , a recording unit 330 , a subject range finder 340 , and an optimum control calculation unit 350 .

[0044] The gimbal 310 is configured to be able to mount a camera, and under the control of the moving body 200 and the optimal control calculation unit 350, maintains the camera horizontal and suppresses vibrations transmitted to the camera. The imaging unit 320 is configured as a camera mounted on the gimbal 310, and captures an image of an object under the control of the optimal control calculation unit 350. The captured image by the imaging unit 320 is supplied to the optimal control calculation unit 350 and recorded in a recording unit 330 composed of a recording medium or the like detachable from the imaging unit 320. The object rangefinder 340 is configured as a distance measurement sensor such as LiDAR, and measures the distance between the object of the imaging unit 320 to be inspected, for example, and the moving body 200, and supplies the measured value to the optimal control calculation unit 350. The optimal control calculation unit 350 is configured as an imaging control device of the present disclosure. The optimum control calculation unit 350 is configured with an integrated circuit such as a SoC (System-on-a-Chip), and executes optimum control calculation processing for optimally controlling image capture by the imaging unit 320 (camera). The functional configuration realized by the optimum control calculation unit 350 will be described later.

[0045] As described above, in the imaging system shown in Fig. 3, the optimal control calculation process for the camera is executed on the payload 300 side. However, as in the imaging system shown in Fig. 4, the optimal control calculation process for the camera may be executed on the mobile body 200 side by providing the optimal control calculation unit 350 on the mobile body 200 side. Furthermore, for example, the optimal control calculation unit 350 may be provided on a cloud server (not shown) that can communicate with the mobile body 200 and the payload 300, so that the optimal control calculation process for the camera is executed on the cloud.

[0046] 4. First Embodiment (Calculation of Appropriate Shutter Speed) (Functional Configuration of Optimal Control Calculation Unit) An example of the functional configuration of the optimal control calculation unit 350 of the first embodiment will be described with reference to FIG.

[0047] 5 is realized by the optimum control calculation unit 350 executing a program stored in a memory (not shown) etc. Specifically, the optimum control calculation unit 350 realizes the function blocks including a movement speed acquisition unit 351, a separation distance acquisition unit 352, a shutter speed calculation unit 353, a brightness calculation unit 354, an ISO sensitivity calculation unit 355, and an imaging control unit 356.

[0048] The movement speed acquisition unit 351 acquires the movement speed (flight speed) of the moving body 200 from the position information acquired by the sensor unit 210 of the moving body 200 .

[0049] Separation distance acquisition section 352 acquires the distance between the subject and moving body 200 measured by subject rangefinder 340 as the separation distance.

[0050] The shutter speed calculation unit 353 calculates the shutter speed of the imaging unit 320 (camera) based on the movement speed acquired by the movement speed acquisition unit 351 and the separation distance acquired by the separation distance acquisition unit 352 .

[0051] The brightness calculation unit 354 calculates the brightness of the subject based on a live view image acquired by the imaging unit 320 while the moving body 200 is moving. Then, the brightness calculation unit 354 sets an appropriate exposure for the captured image based on the calculated brightness of the subject.

[0052] The ISO sensitivity calculation unit 355 calculates the ISO sensitivity for photographing at the exposure set by the brightness calculation unit 354 based on the shutter speed calculated by the shutter speed calculation unit 353 .

[0053] The shooting control unit 356 controls shooting by the imaging unit 320 using the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 .

[0054] (Flow of Image Capture Process by Moving Object) The flow of image capture process by the moving object 200 in the image capture system of this embodiment will be described with reference to the flowchart of FIG.

[0055] In step S11, the input / output device 100 inputs the focal length of the lens of the imaging unit 320 (camera) and the pixel size of the image sensor in response to a user operation.

[0056] In step S12, the input / output device 100 sets the lens aperture value and the allowable amount of blur for the captured image in response to user operation. The lens aperture value is calculated based on the "focus range" input by the user as information about the desired captured image. The allowable amount of blur is calculated as the required pixel size based on the "required image sharpness" input by the user as information about the desired captured image and the pixel size of the image sensor described above.

[0057] In this way, the input and set focal length, aperture value, and allowable amount of blur are transmitted from the input / output device 100 to the moving body 200 and the payload 300 .

[0058] In step S13 , the movement control unit 230 starts the movement of the moving object 200 in response to a user's operation on the input / output device 100 .

[0059] In step S14, the optimum control calculation unit 350 performs optimum control calculation processing for the imaging unit 320 (camera) based on various information, thereby capturing an image of the subject. Details of the optimum control calculation processing will be described later with reference to the flowchart in FIG. 7.

[0060] In step S15, the movement control unit 230 determines whether the movement of the moving body 200 and the capturing of images by the imaging unit 320 (camera) have been completed based on the operation information from the input / output device 100 and the pre-set route information.

[0061] If it is determined in step S15 that the movement and photographing are not completed, the process returns to step S14, and the optimum control calculation process is repeated. On the other hand, if it is determined in step S15 that the movement and photographing are completed, the photographing process by the moving body 200 ends.

[0062] (Details of Optimal Control Calculation Processing) Next, details of the optimal control calculation processing executed in step S14 of the above-mentioned photographing processing will be described with reference to the flowchart of Fig. 7. The optimal control calculation processing of Fig. 7 is executed while the moving body 200 is moving.

[0063] In step S31 , the moving speed acquisition unit 351 acquires the moving speed of the moving body 200 .

[0064] In step S32, the separation distance acquisition unit 352 acquires the separation distance (the distance between the subject and the moving body 200).

[0065] In step S33, the shutter speed calculation unit 353 calculates an appropriate shutter speed using the above-mentioned formula based on the acquired movement speed and separation distance, as well as the focal length input by the input / output device 100 and the allowable amount of blur of the captured image that is set in advance by the input / output device 100.

[0066] In step S34, the brightness calculation unit 354 calculates the brightness of the subject based on a live view image acquired while the moving object 200 is moving.

[0067] In step S35, the brightness calculation unit 354 sets an appropriate exposure for the captured image based on the calculated brightness of the subject.

[0068] In step S36 , the ISO sensitivity calculation unit 355 calculates the ISO sensitivity for photographing at the appropriate exposure set by the brightness calculation unit 354 based on the shutter speed calculated by the shutter speed calculation unit 353 .

[0069] Then, in step S37 , the photographing control unit 356 uses the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 to control photographing of the subject by the image capturing unit 320 .

[0070] According to the above processing, even a user who is not familiar with cameras can take a photograph at an appropriate shutter speed according to the moving speed and distance of the moving object without having to make complicated settings, thereby preventing photographic errors such as blurred images due to the movement of the moving object.

[0071] 5. Second Embodiment (Restrictions When Shooting with Proper Exposure is Unavailable) Although this differs depending on the use case and the user, in some cases, a desired image cannot be obtained if the ISO sensitivity is set to a certain level or higher in a dark environment such as a dark place. In the second embodiment, a configuration will be described in which, when such a situation is known in advance, an upper limit for the ISO sensitivity is set, and underexposure shooting can be performed without increasing the ISO sensitivity above the upper limit.

[0072] (Functional Configuration of Optimal Control Calculation Unit) An example of the functional configuration of the optimal control calculation unit 350 of the second embodiment will be described with reference to FIG.

[0073] 8 is realized by the optimum control calculation unit 350 executing a program stored in a memory (not shown) etc. Specifically, the optimum control calculation unit 350 realizes function blocks including a movement speed acquisition unit 351, a separation distance acquisition unit 352, a shutter speed calculation unit 353, a brightness calculation unit 354, an ISO sensitivity calculation unit 355, an imaging control unit 356, and an ISO sensitivity determination unit 361.

[0074] That is, the optimum control calculation section 350 shown in FIG. 8 differs from the optimum control calculation section 350 described with reference to FIG. 5 in that it further includes an ISO sensitivity determination section 361 .

[0075] The ISO sensitivity determination unit 361 calculates the upper limit of the ISO sensitivity based on the noise level (hereinafter referred to as the allowable noise level) that is allowable in the captured image, which is set in advance by the user, and determines whether the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 exceeds the upper limit.

[0076] (Flow of Image Capture Process by Moving Object) The flow of image capture process by the moving object 200 in the image capture system of this embodiment will be described with reference to the flowchart of FIG.

[0077] In step S111, the input / output device 100 inputs the focal length of the lens of the imaging unit 320 (camera) and the pixel size of the image sensor in response to a user operation.

[0078] In step S112, the input / output device 100 sets the lens aperture value, the allowable amount of blur in the captured image, and the allowable noise level in response to a user operation. The allowable noise level may be set according to the purpose of the image capture, the use case, etc., input and selected by the user.

[0079] In this way, the input and set focal length, aperture value, allowable amount of blur, and allowable noise level are transmitted from the input / output device 100 to the moving body 200 and the payload 300 .

[0080] In step S113 , the movement control unit 230 starts the movement of the moving object 200 in response to a user's operation on the input / output device 100 .

[0081] In step S114, the optimum control calculation unit 350 performs optimum control calculation processing for the imaging unit 320 (camera) based on various information, thereby capturing an image of the subject. Details of the optimum control calculation processing will be described later with reference to the flowchart in FIG. 10.

[0082] In step S115, the movement control unit 230 determines whether the movement of the moving body 200 and the capturing of images by the imaging unit 320 (camera) have been completed based on the operation information from the input / output device 100 and the pre-set route information.

[0083] If it is determined in step S115 that the movement and image capturing are not complete, the process returns to step S14, and the optimal control calculation process is repeated. On the other hand, if it is determined in step S115 that the movement and image capturing are complete, the image capturing process by the moving body 200 ends.

[0084] (Details of Optimal Control Calculation Processing) Next, details of the optimal control calculation processing executed in step S114 of the above-mentioned photographing processing will be described with reference to the flowchart of Fig. 10. The optimal control calculation processing of Fig. 10 is executed while the moving body 200 is moving.

[0085] The processes in steps S131 to S136 in the flowchart of FIG. 10 are the same as those in steps S31 to S36 in the flowchart of FIG. 7, and therefore will not be described again.

[0086] That is, in step S136, the ISO sensitivity calculation unit 355 calculates the ISO sensitivity, and then in step S137, the ISO sensitivity determination unit 361 calculates the upper limit of the ISO sensitivity based on the allowable noise level set by the input / output device 100. Note that the upper limit of the ISO sensitivity may be input directly in the input / output device 100.

[0087] In step S138, the ISO sensitivity determination unit 361 determines whether the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 exceeds the upper limit.

[0088] If it is determined in step S138 that the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 does not exceed the upper limit, that is, if shooting with appropriate exposure is possible, the process proceeds to step S139.

[0089] Then, in step S139 , the shooting control unit 356 controls the shooting of the subject by the image capturing unit 320 using the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 .

[0090] On the other hand, if it is determined in step S138 that the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 exceeds the upper limit, that is, if shooting cannot be performed with proper exposure, the process proceeds to step S140.

[0091] In step S140, the shooting control unit 356 generates presentation information indicating that shooting with proper exposure is not possible. The generated presentation information is transmitted from the optimum control calculation unit 350 to the input / output device 100 and presented to the user. For example, the display 110 of the input / output device 100 displays an icon indicating that shooting with proper exposure is not possible. Furthermore, the display 110 of the input / output device 100 presents a selection screen that allows the user to select whether or not to allow shooting with improper exposure. Selection information indicating the content selected on the selection screen is transmitted from the input / output device 100 to the movement control unit 230 and the optimum control calculation unit 350.

[0092] In step S141, the photographing control unit 356 determines, based on the selection information from the input / output device 100, whether photographing with an inappropriate exposure is permitted.

[0093] If it is determined in step S141 that shooting with an inappropriate exposure is permitted, the process proceeds to step S139, where shooting of the subject by the imaging unit 320 is controlled using an ISO sensitivity that exceeds the upper limit. In other words, shooting with an inappropriate exposure is performed.

[0094] On the other hand, if it is determined in step S141 that photography with inappropriate exposure is not permitted, the process proceeds to step S142.

[0095] In step S142, the movement control unit 230 controls the drive unit 220 to limit the movement speed of the moving body 200. Thereafter, the process returns to step S131, and the subsequent processes are repeated. That is, the movement of the moving body 200 continues with the movement speed limited until the ISO sensitivity calculated by the ISO sensitivity calculation unit 355 falls below the upper limit value.

[0096] According to the above processing, when it is not possible to take a photograph with proper exposure in a dark environment such as a dark place, it is possible to prevent unintentional photographing, and as a result, it is possible to prevent photographing failures.

[0097] 6. Application Examples (Setting the Shutter Speed ​​in Steps) Even if an appropriate shutter speed is calculated as in the above-described embodiment, the actual shutter speed of a camera can only be set in steps such as 1 / 1000, 1 / 2000, etc. Furthermore, in the real world, fluctuations in flight speed often occur due to factors such as drone flight accuracy and wind.

[0098] Therefore, as shown in FIG. 11, the shutter speed for the separation distance may be set in steps corresponding to the separation distance.

[0099] Specifically, as shown in Figure 12, when the flight speed is 3 m / s or more and the separation distance is 1 to 10 m, the shutter speed is set to 1 / 4000, when the separation distance is 10 to 20 m the shutter speed is set to 1 / 2500, and when the separation distance is 20 m or more the shutter speed is set to 1 / 1000. When the flight speed is 1 to 3 m / s or more and the separation distance is 1 to 10 m the shutter speed is set to 1 / 3000, when the separation distance is 10 to 20 m the shutter speed is set to 1 / 1500, and when the separation distance is 20 m or more the shutter speed is set to 1 / 1000. When the flight speed is 1 m / s or less, the shutter speed is set to 1 / 1000 regardless of the separation distance.

[0100] This allows the shutter speed to be set appropriately in accordance with the actual camera, and also allows the shutter speed to be set stably even with fluctuations in flight speed.

[0101] In addition, in Figure 11, in the case of photography where the flight speed is 3 m / s or more and the separation distance is 6 m or less, as shown in the dotted line frame UD, the shutter speed may not be defined, as this is a case that does not actually occur.

[0102] (Setting the shutter speed according to the application) The relationship between the separation distance and the flight speed (movement speed) is thought to differ depending on the application of the image capture. For example, the resolution required for surveying is often lower than the resolution required for inspection, such as 1 cm / pix, so images can be captured from a higher altitude. When capturing images from a high altitude, the separation distance is greater, so the shutter speed can be kept low. In other words, automatically setting an appropriate shutter speed according to the separation distance and resolution can be applied to a variety of applications.

[0103] For example, if the application is inspection, the separation distance will be close to medium distance and the flight speed will be relatively fast, so the shutter speed will be set to the range surrounded by the dashed frame P1 among the shutter speeds for the separation distances shown in Figure 13.

[0104] When the application is inspection, the separation distance is long and the flight speed is relatively fast, so the shutter speed is set to the range surrounded by the dashed frame P2 among the shutter speeds for the separation distances shown in Figure 13.

[0105] When manual photography is performed regardless of the application, a slow flight speed is expected regardless of the separation distance, so the shutter speed is set to the range surrounded by the dashed frame P3 among the shutter speeds for the separation distances shown in Figure 13.

[0106] 7. Example of Computer Hardware Configuration The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware, a general-purpose personal computer, or the like.

[0107] 14 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program. For example, a cloud server provided with the optimal control calculation unit 350 may be configured by a computer 500 having a configuration similar to that shown in FIG.

[0108] A CPU (Central Processing Unit) 501 , a ROM (Read Only Memory) 502 , and a RAM (Random Access Memory) 503 are interconnected by a bus 504 .

[0109] An input / output interface 505 is also connected to the bus 504. An input unit 506 including buttons, a touch panel, etc., and an output unit 507 including a display, a speaker, etc. are connected to the input / output interface 505. Also connected to the input / output interface 505 are a storage unit 508 including a hard disk, a nonvolatile memory, etc., a communication unit 509 including a network interface, etc., and a drive 510 that drives removable media 511.

[0110] In the computer 500 configured as described above, the CPU 501 performs the above-described series of processes by, for example, loading a program stored in the memory unit 508 into the RAM 503 via the input / output interface 505 and the bus 504 and executing it.

[0111] The program executed by the CPU 501 is installed in the storage unit 508 by being recorded on, for example, a removable medium 511 or provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting.

[0112] The program executed by computer 500 may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0113] In this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all of the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0114] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0115] The embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure.

[0116] For example, the embodiment of the present disclosure can be configured as a cloud computing system in which a single function is shared and processed collaboratively by multiple devices via a network.

[0117] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by a plurality of devices.

[0118] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0119] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0120] Furthermore, the technology according to the present disclosure may have the following configurations: (1) A photographing control method including: acquiring a moving speed of a moving body; acquiring a separation distance between the moving body and a subject of an image captured by a camera mounted on the moving body; and calculating a shutter speed of the camera based on the moving speed and the separation distance. (2) The photographing control method described in (1), in which the shutter speed is calculated based on the moving speed and the separation distance, as well as a focal length of the camera and a preset allowable amount of blur for the captured image. (3) The photographing control method described in (2), in which the allowable amount of blur is set according to a pixel size of an image sensor of the camera. (4) The photographing control method described in (3), in which the exposure of the captured image is set based on the brightness of the subject, and an ISO sensitivity for capturing an image with the exposure is calculated based on the shutter speed. (5) The photographing control method described in (4), in which the brightness of the subject is calculated based on a live view image captured while the moving body is moving. (6) The photography control method according to (4) or (5), which calculates an upper limit of the ISO sensitivity based on a preset allowable noise level, and generates presentation information indicating that photography with the exposure is not possible when the ISO sensitivity calculated based on the shutter speed exceeds the upper limit. (7) The photography control method according to (6), which limits the movement speed of the moving object when photography with the exposure is not allowed. (8) The photography control method according to (7), which limits the movement speed of the moving object until the ISO sensitivity calculated based on the shutter speed falls below the upper limit. (9) The photography control method according to any of (1) to (8), in which the moving object is a drone. (10) An photography control device comprising: a movement speed acquisition unit that acquires the movement speed of the moving object; a separation distance acquisition unit that acquires a separation distance between the moving object and a subject of an image captured by a camera mounted on the moving object; and a shutter speed calculation unit that calculates the shutter speed of the camera based on the movement speed and the separation distance.(11) A program for causing a computer to execute a process including: acquiring the moving speed of a moving body; acquiring a separation distance between the moving body and a subject of an image captured by a camera mounted on the moving body; and calculating a shutter speed of the camera based on the moving speed and the separation distance.

[0121] 100 Input / output device, 110 Display, 120 Touch panel, 130 Button, 140 Stick, 200 Moving body, 210 Sensor unit, 220 Drive unit, 230 Movement control unit, 300 Payload, 310 Gimbal, 320 Imaging unit, 330 Recording unit, 340 Subject rangefinder, 350 Optimum control calculation unit, 351 Movement speed acquisition unit, 352 Separation distance acquisition unit, 353 Shutter speed calculation unit, 354 Brightness calculation unit, 355 ISO sensitivity calculation unit, 356 Shooting control unit, 361 ISO sensitivity determination unit

Claims

1. A photography control method including: acquiring the movement speed of a moving body; acquiring a separation distance between the moving body and a subject of an image captured by a camera mounted on the moving body; and calculating a shutter speed of the camera based on the movement speed and the separation distance.

2. The photography control method according to claim 1, wherein the shutter speed is calculated based on the focal length of the camera and a preset allowable amount of blur of the photographed image in addition to the movement speed and the separation distance.

3. The photography control method according to claim 2, wherein the allowable amount of blur is set according to the pixel size of the image sensor of the camera.

4. The photography control method according to claim 3, further comprising the steps of: setting the exposure of the photographed image based on the brightness of the subject; and calculating the ISO sensitivity for photographing at said exposure based on the shutter speed.

5. The photographing control method according to claim 4, wherein the brightness of the subject is calculated based on a live view image acquired while the moving object is moving.

6. The photography control method according to claim 4, wherein an upper limit of the ISO sensitivity is calculated based on a preset allowable noise level, and when the ISO sensitivity calculated based on the shutter speed exceeds the upper limit, presentation information is generated to the effect that photography cannot be performed at the exposure.

7. The photography control method according to claim 6, wherein the moving speed of the moving object is limited if photography at the exposure is not permitted.

8. The photography control method according to claim 7, wherein the moving speed of the moving object is limited until the ISO sensitivity calculated based on the shutter speed falls below the upper limit value.

9. The photography control method according to claim 1, wherein the moving body is a drone.

10. An imaging control device comprising: a movement speed acquisition unit that acquires the movement speed of a moving body; a separation distance acquisition unit that acquires the separation distance between the moving body and a subject of an image captured by a camera mounted on the moving body; and a shutter speed calculation unit that calculates the shutter speed of the camera based on the movement speed and the separation distance.

11. A program for causing a computer to execute a process including: acquiring the moving speed of a moving body; acquiring the distance between the moving body and a subject in an image captured by a camera mounted on the moving body; and calculating the shutter speed of the camera based on the moving speed and the distance.

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