Imaging device, imaging method, and program

Abstract

To properly adjust a focal position.SOLUTION: An imaging device 100 includes: an imaging element; an object information acquisition part which acquires the position information on an object existing in an imaging region AR0 of the imaging element; and a focus position control part which controls a focal position of the imaging device 100. The focus position control part aligns the focus position with the object which is located in the outside of an object region AR between a first position AX1 which becomes a first distance L1 in the distance from the imaging device 100 and a second position AX2 which becomes a second distance L2 shorter than the first distance L1 in the distance from the imaging device 100 and in the imaging region AR0. During a period in which the object is outside the object region AR and in the imaging region AR0, the focal position is kept aligned with the object, and when the object moves into the object region AR, the focal position is removed from the object.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] There are known autofocus imaging devices that automatically set a focal position. For example, Patent Document 1 describes that the focus is adjusted to a predetermined position designated by the user. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 141746 Summary of the Invention [Problem to be solved by the invention]

[0004] In an autofocus imaging device, it is required to properly adjust the focus.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide an imaging device, an imaging method, and a program that are capable of appropriately adjusting the focus. [Means for solving the problem]

[0006] An imaging device according to one aspect of the present invention is an imaging device capable of capturing an image of an object, and includes an imaging element, an object information acquisition unit that acquires positional information of an object present in an imaging area of ​​the imaging element, and a focus position control unit that controls a focus position of the imaging device, wherein the focus position control unit adjusts the focus position to an object that is present within the imaging area and outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and continues to adjust the focus position to the object while the object is outside the target area but within the imaging area, and when the object moves into the target area, moves the focus position away from the object.

[0007] An imaging method according to one aspect of the present invention is an imaging method for imaging an object, and includes the steps of acquiring positional information of an object present in an imaging area and controlling a focal position of an imaging device, wherein in the step of controlling the focal position, the focal position is adjusted to an object that is present within the imaging area and outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and the focal position is kept adjusted to the object while the object is outside the target area but within the imaging area, and when the object moves into the target area, the focal position is moved away from the object.

[0008] A program according to one aspect of the present invention is a program that causes a computer to execute an imaging method for imaging an object, and causes the computer to execute the steps of acquiring positional information of an object present in an imaging area and controlling a focal position of an imaging device, wherein in the step of controlling the focal position, the focal position is adjusted to an object that is present within the imaging area but outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and while the object is outside the target area but present within the imaging area, the focal position continues to be adjusted to the object, and when the object moves into the target area, the focal position is moved away from the object. [Effects of the Invention]

[0009] According to the present invention, it is possible to appropriately adjust the focus. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic block diagram of an imaging device according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a target region. [Figure 3] FIG. 3 is a schematic diagram illustrating an example of a target region. [Figure 4] FIG. 4 is a schematic diagram showing another example of the target region. [Figure 5] FIG. 5 is a schematic diagram showing another example of the target region. [Figure 6] FIG. 6 is a flowchart illustrating the process flow for setting the focal position. [Figure 7] FIG. 7 is a schematic diagram illustrating an example in which the motion of an object is set as a predetermined condition. [Figure 8] FIG. 8 is a flowchart illustrating the processing flow for setting the focal position in the second embodiment. [Figure 9] FIG. 9 is a schematic diagram illustrating an example in which a plurality of objects exist in the target area. [Figure 10] FIG. 10 is a flowchart illustrating a process flow for setting a focal position according to the third embodiment. [Figure 11] FIG. 11 is a schematic diagram for explaining a method for setting the focal position in the fourth embodiment. [Figure 12] FIG. 12 is a flowchart illustrating a process flow for setting a focal position according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0012] (First embodiment) (Configuration of imaging device) FIG. 1 is a schematic block diagram of an imaging device according to a first embodiment. The imaging device 100 according to the first embodiment is an imaging device that captures an image of an object within an imaging range. The imaging device 100 is an autofocus camera that can automatically set the focal position. The imaging device 100 may be a video camera that captures moving images by capturing images every predetermined frame, or may be a camera that captures still images. The imaging device 100 may be used for any purpose, and may be used, for example, as a surveillance camera set at a predetermined position inside a facility or outdoors.

[0013] As shown in FIG. 1, the imaging device 100 includes an optical element 10, an imaging element 12, an image processing circuit 13, an object position measurement unit 14, an input unit 16, a display unit 18, a communication unit 20, a memory unit 22, and a control unit 24.

[0014] The optical element 10 is an element of an optical system such as a lens, etc. The optical element 10 may be one or more.

[0015] The imaging element 12 is an element that converts light incident through the optical element 10 into an image signal, which is an electrical signal. The imaging element 12 is, for example, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor.

[0016] The image processing circuit 13 generates image data for each frame from the image signal generated by the imaging element 12. The image data is data including, for example, information on the luminance and color of each pixel in one frame, and may be data to which a gradation is assigned for each pixel.

[0017] The object position measuring unit 14 is a sensor that measures the position of the object to be measured with respect to the imaging device 100 (the relative position of the object). The object here may be any object, and may be a living or inanimate object, and the same applies hereinafter. Furthermore, the object here may refer to a movable object, but is not limited thereto and may also refer to an immobile object.

[0018] In this embodiment, the object position measuring unit 14 measures the distance from the image capturing device 100 to the object as the relative position of the object. The object position measuring unit 14 may be any sensor capable of measuring the relative position of the object, and may be, for example, a TOF (Time Of Flight) sensor. When the object position measuring unit 14 is a TOF sensor, for example, a light-emitting element (e.g., an LED (Light Emitting Diode)) that irradiates light and a light-receiving unit that receives the light are provided, and the distance to the object is measured based on the time of flight of light that is irradiated from the light-emitting element to the object and returned to the light-receiving unit. Note that the object position measuring unit 14 may measure, for example, the direction in which the object exists relative to the image capturing device 100 in addition to measuring the distance from the image capturing device 100 to the object as the relative position of the object. In other words, the object position measuring unit 14 may measure, as the relative position of the object, the position (coordinates) of the object in a coordinate system with the image capturing device 100 as the origin.

[0019] The input unit 16 is a mechanism for accepting input (operation) from the user, and may be, for example, a button, a keyboard, or a touch panel.

[0020] The display unit 18 is a display panel that displays an image. The display unit 18 may be capable of displaying an image for the user to set a target area AR (described later) in addition to the image captured by the imaging device 100.

[0021] The communication unit 20 is a communication module that communicates with an external device, and may be, for example, an antenna, a Wi-Fi (registered trademark) module, etc. The imaging device 100 communicates with the external device via wireless communication, but wired communication may also be used, and any communication method may be used.

[0022] The storage unit 22 is a memory that stores various information such as captured image data, calculation contents and programs of the control unit 24, and includes at least one of a main storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and an external storage device such as an HDD (Hard Disk Drive). The program for the control unit 24 stored in the storage unit 22 may be stored in a recording medium that can be read by the imaging device 100.

[0023] The control unit 24 is a computing device and includes an arithmetic circuit such as a CPU (Central Processing Unit). The control unit 24 includes a target area acquisition unit 30, an object information acquisition unit 32, a focus position control unit 34, an imaging control unit 36, and an image acquisition unit 38. The control unit 24 implements the target area acquisition unit 30, the object information acquisition unit 32, the focus position control unit 34, the imaging control unit 36, and the image acquisition unit 38 by reading and executing a program (software) from the storage unit 22. The control unit 24 may implement these processes using a single CPU, or may be provided with multiple CPUs and execute the processes using the multiple CPUs. At least a portion of the processes performed by the target area acquisition unit 30, the object information acquisition unit 32, the focus position control unit 34, the imaging control unit 36, and the image acquisition unit 38 may be implemented using hardware circuits.

[0024] (Target area acquisition section) The target area acquisition unit 30 acquires information about a target area AR set within the imaging area of ​​the imaging device 100. The target area AR is an area set to automatically adjust the focus position. The information about the target area AR is information indicating the position of the target area AR, i.e., position information about the target area AR. The target area AR will be described below.

[0025] 2 and 3 are schematic diagrams for explaining an example of a target area. FIG. 2 is a view of the imaging device 100 and the target area AR viewed from above in the vertical direction, and FIG. 3 is a view of the imaging device 100 and the target area AR viewed from the horizontal direction. Hereinafter, direction Z is defined as the vertical direction, direction X is defined as one horizontal direction perpendicular to direction Z, and direction Y is defined as a direction (horizontal direction) perpendicular to direction Z and direction X. As shown in FIGS. 2 and 3, the range in which an image can be captured by the imaging device 100 is defined as an imaging area AR0. The imaging area AR0 refers to the area (space) that falls within the angle of view of the imaging element 12, in other words, the range in real space that is captured as an image. The target area AR is an area (space) set within the range of the imaging area AR0.

[0026] More specifically, the target area AR is an area within the imaging area AR0 between a first position AX1 and a second position AX2. The first position AX1 is a position at a first distance L1 from the imaging device 100, and the second position AX2 is a position at a second distance L2 that is shorter than the first distance L1. As shown in FIGS. 2 and 3 , in this embodiment, the first position AX1 can be considered to be a virtual plane that includes positions (coordinates) within the imaging area AR0 that are at the first distance L1 from the imaging device 100. Similarly, the second position AX2 can be considered to be a virtual plane that includes positions (coordinates) within the imaging area AR0 that are at the second distance L2 from the imaging device 100. That is, the target area AR can be considered to be a space within the imaging area AR0 that is surrounded by a virtual plane that is at the second distance L2 from the imaging device 100 and a virtual plane that is at the first distance L1 from the imaging device 100. Note that the first position AX1 is not limited to being a virtual plane on which all positions (coordinates) included in the first position AX1 are the first distance L1 from the imaging device 100, but may be a virtual plane on which at least some positions (coordinates) included in the first position AX1 are the first distance L1 from the imaging device 100. Similarly, the second position AX2 may be a virtual plane on which at least some positions (coordinates) included in the second position AX2 are the second distance L2 from the imaging device 100.

[0027] 4 and 5 are schematic diagrams showing other examples of the target area. In the description of FIGS. 2 and 3, the target area AR is delimited by the first position AX1 and the second position AX2 with respect to the imaging area AR0 in the optical axis direction of the imaging device 100 (the depth direction of the image). However, the target area AR is not delimited with respect to the imaging area AR0 in the radial direction (the direction of the angle of view) with respect to the optical axis direction of the imaging device 100. In other words, the end face of the target area AR in the direction of the angle of view coincides with the end face of the imaging area AR0 in the direction of the angle of view. However, this is not limited thereto, and the target area AR may also be delimited with respect to the imaging area AR0 in the direction of the angle of view. That is, for example, as shown in FIGS. 4 and 5, the target area AR may also be delimited with respect to the imaging area AR0 in the direction of the angle of view by the third position AX3. In this example, the third position AX3 is a virtual surface (here, a closed curved surface shaped like a cylindrical side surface) that includes positions (coordinates) that are a predetermined distance outward in the radial direction with respect to the optical axis LX of the imaging device 100. In this case, the target area AR is an area (space) surrounded by the first position AX1, the second position AX2, and the third position AX3. Note that the third position AX3 is not limited to being a virtual plane in which all positions (coordinates) included in the third position AX3 are the first distance L1 from the optical axis LX, but may be a virtual plane in which at least some positions (coordinates) included in the third position AX3 are the third distance L3 from the optical axis LX. For example, the third position AX3 may be a virtual plane that expands radially outward (in the horizontal and elevation directions) at a predetermined angle as it moves away from the image capture device 100 along the optical axis direction.

[0028] The size and shape of the target area AR are not limited to those described above and may be arbitrary. In the above description, the target area AR is an area set within the imaging area AR0, but this is not limiting. For example, if the range measurable by the object position measurement unit 14 is defined as a ranging area (ranging space), the target area AR may be an area set within the ranging area. In this case, the imaging area AR0 in FIGS. 2 to 5 may be treated as the ranging area.

[0029] The target area acquisition unit 30 may acquire information about the target area AR using any method. For example, the position of the target area AR may be set in advance. In this case, the target area acquisition unit 30 may read the position information of the target area AR set in advance from the storage unit 22, or may acquire the position information of the target area AR from another device via the communication unit 20. For example, if the position of the target area AR is not set in advance, the target area acquisition unit 30 may automatically set the position of the target area AR. For example, the user may set the position of the target area AR. In this case, for example, the user may input information specifying the position of the target area AR (e.g., values ​​of the first distance L1, the second distance L2, and the third distance L3) to the input unit 16, and the target area acquisition unit 30 may set the target area AR based on the position information of the target area AR specified by the user. For example, the target area AR may be set by specifying coordinates. That is, in the example of FIG. 2, coordinates P1, P2, P3, and P4 that are the vertex positions of the target area AR may be specified, and the area enclosed by the coordinates P1 to P4 may be set as the target area AR.

[0030] (Object information acquisition unit) The object information acquisition unit 32 acquires position information of an object present within the imaging area AR0. The object information acquisition unit 32 controls the object position measurement unit 14 to cause the object position measurement unit 14 to measure the relative position of the object with respect to the imaging device 100. The object information acquisition unit 32 acquires the measurement result of the object's relative position with respect to the imaging device 100 by the object position measurement unit 14 as object position information. The object information acquisition unit 32 acquires object position information sequentially by acquiring object position information at predetermined time intervals. The object information acquisition unit 32 can also acquire information indicating the shape of the object (e.g., the 3D shape of the object) based on the object position information. For example, the object information acquisition unit 32 can acquire the 3D shape of the object by accumulating multiple pieces of position information, such as TOF image information.

[0031] (Focus position control unit) The focus position control unit 34 sets the focus position of the imaging device 100. The focus position control unit 34 controls the focus position by controlling the position of the optical element 10, that is, by moving the position of the optical element 10.

[0032] The focus position control unit 34 adjusts the focus position to an object present within the target area AR. In other words, the focus position control unit 34 sets the focus position to the position of an object determined to be present within the target area AR. In this embodiment, the focus position control unit 34 determines whether an object is present within the target area AR based on the object's position information acquired by the object information acquisition unit 32. If the position of the object acquired by the object information acquisition unit 32 overlaps with the position of the target area AR, the focus position control unit 34 determines that the object is present within the target area AR and adjusts the focus position to the object's position acquired by the object information acquisition unit 32. That is, for example, if the distance from the imaging device 100 to the object is equal to or less than the first distance L1 and equal to or greater than the second distance L2, the focus position control unit 34 determines that the object is present within the target area AR and adjusts the focus position to the object. On the other hand, the focus position control unit 34 does not adjust the focus position to an object not present within the target area AR. That is, for example, if the distance from the imaging device 100 to the object is farther than the first distance L1 or closer than the second distance L2, the focus position control unit 34 determines that the object does not exist within the target area AR and does not adjust the focus position to the object.

[0033] The focus position control unit 34 continues to focus on the object for a period during which the object for which the focus position is set is present within the target area AR. That is, the focus position control unit 34 determines whether the object continues to exist within the target area AR based on the object's position information acquired at predetermined time intervals by the object information acquisition unit 32, and continues to focus on the object for a period during which the object continues to exist within the target area AR. On the other hand, if the object for which the focus position is set moves outside the target area AR, i.e., if it is no longer present within the target area AR, the focus position control unit 34 moves the focus position away from the object and focuses on a position other than the object.

[0034] Note that the focus position control unit 34 does not need to adjust the focus position for an object that has been present in the target area AR since the imaging device 100 started operating (the timing when imaging is possible). That is, the focus position control unit 34 may adjust the focus position for an object that enters the target area AR after operation has started. In other words, the focus position control unit 34 may adjust the focus position for an object that exists in the target area AR at a certain timing but did not exist in the target area AR at a timing prior to that timing, from the timing when the object begins to exist in the target area AR. In other words, when an object moves from outside the target area AR into the target area AR, the focus position control unit 34 may recognize the object as a target to be focused on. That is, the focus position control unit 34 may adjust the focus position for an object that moves from outside the target area AR into the target area AR.

[0035] Furthermore, when no object is present within the target area AR, the focus position control unit 34 may adjust the focus position to a preset position. The position may be set arbitrarily, but is preferably set within the target area AR, such as the center position of the target area AR.

[0036] An example of the focus position setting described above will be described with reference to FIG. 2. FIG. 2 illustrates an example in which object A moves from position A0, passing through positions A1 and A2, to position A3 toward the image capture device 100. Position A0 is located outside the target area AR because the distance to the image capture device 100 is greater than the first distance L1. Positions A1 and A2 are located within the target area AR because the distance to the image capture device 100 is less than the first distance L1 but greater than the second distance L2. Position A3 is located closer to the image capture device 100 than the second distance L2 and therefore outside the target area AR. In this case, the focus position control unit 34 does not focus on object A when object A is located at position A0, but instead focuses on a set position, for example. Then, the focus position control unit 34 focuses on object A when object A is located at position A1, i.e., when object A enters the target area AR. The focus position control unit 34 continues to adjust the focus position on object A even when object A is present at position A2, and when object A moves to position A3, that is, when object A moves out of the target area AR, it removes the focus position from object A and returns the focus position to the set position. That is, the focus position control unit 34 adjusts the focus position on object A from the time when object A enters the target area AR, moves the focus position in accordance with the moving object A while object A is moving within the target area AR, and removes the focus position from object A when object A moves out of the target area AR.

[0037] The focal position may be set by the user. In this case, for example, the camera may be able to switch between an auto mode in which the focal position is automatically set and a manual mode in which the user sets the focal position. In the auto mode, the focal position is set by the focal position control unit 34 as described above. On the other hand, in the manual mode, the user inputs an operation to set the focal position into the input unit 16, and the focal position control unit 34 sets the focal position in accordance with the user's operation.

[0038] (imaging control unit) The imaging control unit 36 ​​controls imaging by the imaging device 100 to capture an image. The imaging control unit 36 ​​controls, for example, the imaging element 12 to cause the imaging element 12 to acquire an image signal. For example, the imaging control unit 36 ​​may cause the imaging element 12 to acquire an image signal automatically, or may cause the imaging element 12 to acquire an image signal in response to a user operation.

[0039] (Image acquisition section) The image acquisition unit 38 acquires image data acquired by the imaging element 12. The image acquisition unit 38, for example, controls the image processing circuit 13 to cause the image processing circuit 13 to generate image data from the image signal generated by the imaging element 12, and acquires the image data. The image acquisition unit 38 stores the image data in the storage unit 22.

[0040] (Focus position setting flow) Next, the process flow for setting the focal position described above will be described. FIG. 6 is a flowchart illustrating the process flow for setting the focal position. As shown in FIG. 6, the control unit 24 acquires information about the target area AR using the target area acquisition unit 30 (step S10), and acquires position information of the object using the object information acquisition unit 32 (step S12). The order of steps S10 and S12 may be arbitrary. The control unit 24 determines, using the focus position control unit 34, whether the object is located within the target area AR based on the position information of the object (step S14). If the object is not located within the target area AR (step S14; No), the process returns to step S12 and continues acquiring position information of the object. On the other hand, if the object is located within the target area AR (step S14; Yes), the focus position control unit 34 adjusts the focal position to the object (step S16). Thereafter, the process continues to acquire position information of the object and determines whether the object has moved outside the target area AR (step S18). If the object does not move outside the target area AR (step S18; No), that is, if the object continues to exist within the target area AR, the process returns to step S16, and the focus position continues to be adjusted to the object. If the object moves outside the target area AR (step S18; Yes), the focus position control unit 34 removes the focus position from the object (step S20). Thereafter, if the process is not to be ended (step S22; No), the process returns to step S12, and if the process is to be ended (step S22; Yes), the process ends.

[0041] (effect) As described above, the imaging device 100 according to this embodiment includes the imaging element 12, the object information acquisition unit 32 that acquires position information of an object present in the imaging area AR0 of the imaging element 12, and the focus position control unit 34 that controls the focus position of the imaging device 100. The focus position control unit 34 adjusts the focus position to an object present in the target area AR, keeps the focus position adjusted to the object while the object is present in the target area AR, and shifts the focus position away from the object when the object moves out of the target area AR. The target area AR is the area between a first position AX1, where the distance from the imaging device 100 is a first distance L1, and a second position AX, where the distance from the imaging device 100 is a second distance L2 that is shorter than the first distance L1.

[0042] Here, autofocus imaging devices are required to appropriately adjust the focal position. In contrast, the imaging device 100 according to this embodiment adjusts the focal position on an object present within the target area AR, and continues to adjust the focal position on the object if the object remains within the target area AR. When the object leaves the target area AR, the focal position is shifted. Therefore, it is possible to maintain focus on an object present in a target area, which is a region of interest in surveillance, for example. Furthermore, when the object leaves the region of interest, for example, when the object is farther away than the first distance L1 or closer than the second distance L2, the focal position is shifted from the object, thereby preventing the focus from shifting from the region of interest. Therefore, according to this embodiment, it is possible to appropriately adjust the focal position.

[0043] Furthermore, the focal position control unit 34 controls the focal position by moving the position of the optical element 10 provided in the imaging device 100. According to this embodiment, it is possible to appropriately adjust the focal position.

[0044] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that the focal position is adjusted to an object that exists within the target area AR and satisfies a predetermined condition. Explanations of the configurations of the second embodiment that are common to the first embodiment will be omitted.

[0045] In the second embodiment, the focus position control unit 34 adjusts the focus position on an object that exists within the target area AR and satisfies a predetermined condition. The focus position control unit 34 does not adjust the focus position on an object that does not satisfy at least one of the following conditions: existence within the target area AR; and the predetermined condition. The focus position control unit 34 continues to adjust the focus position on the object for a period during which the object satisfies the predetermined condition and remains within the target area AR. On the other hand, the focus position control unit 34 shifts the focus position away from the object when the object no longer satisfies at least one of existence within the target area AR and the predetermined condition. That is, for example, the focus position control unit 34 shifts the focus position away from the object when the object satisfies the predetermined condition but moves outside the target area AR, or when the object exists within the target area AR but no longer satisfies the predetermined condition.

[0046] The focus position control unit 34 may determine whether the predetermined conditions are met using any method, but may determine whether the predetermined conditions are met based on at least one of object position information and an image of the object. The object position information here may refer to the measurement results of the object position measurement unit 14, and the image of the object may refer to image data of the object acquired by the image sensor 12.

[0047] The predetermined condition here may be any condition other than the presence of an object within the target area AR. For example, the predetermined condition may be at least one of the following: the object is performing a predetermined motion, the object has a predetermined shape, and the object is facing a predetermined direction. Alternatively, any two of these may be the predetermined conditions, or all of these may be the predetermined conditions. When multiple predetermined conditions are set, the focus position control unit 34 determines that the predetermined conditions are met when all of the conditions are met.

[0048] A case where object movement is the predetermined condition will be described. In this case, the focus position control unit 34 determines whether the object is performing a predetermined movement based on the object's position information continuously acquired in time series. The focus position control unit 34 adjusts the focus position to an object that exists within the target area AR and is performing a predetermined movement. The focus position control unit 34 does not adjust the focus position to an object that does not satisfy at least one of the conditions of being present within the target area AR and performing a predetermined movement. The focus position control unit 34 continues to adjust the focus position to the object for a period during which the object is present within the target area AR and continues performing a predetermined movement. On the other hand, if the object no longer satisfies at least one of the conditions of being present within the target area AR and performing a predetermined movement, the focus position control unit 34 removes the focus position from the object. Note that the movement of the object here refers to the object's movement mode, and may refer to, for example, the object's movement direction and movement speed. For example, if the predetermined movement refers to vertically downward movement at a speed of 10 m / h or more, the focus position control unit 34 adjusts the focus position on an object moving vertically downward within the target area AR at a speed of 10 m / h or more. Note that the movement of an object is not limited to the direction and speed of the object's movement, but may refer to any movement pattern. For example, the movement of an object may refer to at least one of the direction and speed of the object's movement.

[0049] FIG. 7 is a schematic diagram illustrating an example in which the predetermined condition is the movement of an object. In the example of FIG. 7, the predetermined condition is the vertical downward movement of the object (opposite to the Z direction), i.e., the movement direction of the object. The example of FIG. 7 illustrates a case in which object A moves vertically downward from position A0a, passing through positions A1a and A2a, to position A3a, and stops at position A3a. Position A0a is outside the target area AR, while positions A1a, A2a, and A3a are within the target area AR. In this case, when object A is located at position A0a, object A is outside the target area AR, so the focus position control unit 34 does not focus on object A, but instead focuses on a set position, for example. Then, when object A is located at position A1a, i.e., when object A enters the target area AR while moving vertically downward, the focus position control unit 34 focuses on object A. The focal position control unit 34 continues to adjust the focal position to the object A even when the object A is at the position A2a, and when the object A moves to the position A3a and stops, it removes the focal position from the object A and returns the focal position to the set position.

[0050] Next, a case where the shape of an object is set as a predetermined condition will be described. In this case, the focus position control unit 34 determines whether the object has a predetermined shape based on image data containing the object. The focus position control unit 34 adjusts the focus position to an object that exists within the target area AR and has a predetermined shape. The focus position control unit 34 does not adjust the focus position to an object that does not satisfy at least one of the conditions of being present within the target area AR and having a predetermined shape. The focus position control unit 34 continues to adjust the focus position to the object for a period during which the object has the predetermined shape and continues to exist within the target area AR. On the other hand, if the object no longer satisfies at least one of the conditions of being present within the target area AR and having a predetermined shape, the focus position control unit 34 removes the focus position from the object. The shape of the object here may be, for example, at least one of the size and the outer shape of the object. For example, if the predetermined shape refers to an object that is equal to or larger than a predetermined size, the focus position control unit 34 adjusts the focus position to an object that exists within the target area AR and has the predetermined size or larger. Note that 3D shape information acquired by the object information acquisition unit 32 may be used to acquire the shape information of the object.

[0051] A case where the orientation of an object is set as a predetermined condition will be described. In this case, the focus position control unit 34 determines whether the object is facing a predetermined direction based on image data containing the object. The focus position control unit 34 adjusts the focus position to an object that exists within the target area AR and faces the predetermined direction. The focus position control unit 34 does not adjust the focus position to an object that does not satisfy at least one of the conditions of being present within the target area AR and facing the predetermined direction. The focus position control unit 34 continues to adjust the focus position to the object for a period during which the object continues to exist within the target area AR while facing the predetermined direction. On the other hand, if the object no longer satisfies at least one of the conditions of being present within the target area AR and facing the predetermined direction, the focus position control unit 34 removes the focus position from the object. Note that 3D shape information acquired by the object information acquisition unit 32 may be used to acquire information about the object's orientation.

[0052] The predetermined conditions may be set in any manner, for example, they may be set in advance. In this case, the focus position control unit 34 may read information indicating the predetermined conditions (e.g., movement direction and movement speed) from the storage unit 22, or may acquire the predetermined conditions from another device via the communication unit 20. Furthermore, for example, if the predetermined conditions are not set in advance, the focus position control unit 34 may automatically set the predetermined conditions. Furthermore, for example, the user may set the predetermined conditions. In this case, for example, the user may input information specifying the predetermined conditions (e.g., movement direction and movement speed) to the input unit 16, and the focus position control unit 34 may set the predetermined conditions based on the information specified by the user.

[0053] Next, a flow for setting a focal position in the second embodiment will be described. FIG. 8 is a flowchart illustrating a process flow for setting a focal position in the second embodiment. As shown in FIG. 8, the control unit 24 acquires information about the target area AR using the target area acquisition unit 30 (step S30), acquires predetermined conditions using the focus position control unit 34 (step S32), and acquires object position information and information about the conditions using the object information acquisition unit 32 (step S34). The information about the conditions is information for determining whether the object satisfies the predetermined conditions, such as object position information or image data containing the object. Steps S30, S32, and S34 may be performed in any order. The control unit 24 determines, using the focus position control unit 34, whether the object satisfies the predetermined conditions and is located within the target area AR (step S36). If the object does not satisfy at least one of the conditions of satisfying the predetermined conditions and being located within the target area AR (step S36; No), the process returns to step S12 and continues acquiring object position information. On the other hand, if the object satisfies the predetermined conditions and is located within the target area AR (step S36; Yes), the focus position control unit 34 adjusts the focus position on the object (step S38). Thereafter, the process continues to acquire information about the object's position and conditions, and determines whether the object does not satisfy the predetermined conditions or has moved outside the target area AR (step S40). If the object satisfies the predetermined conditions and is located within the target area AR (step S40; No), that is, if the object satisfies the predetermined conditions and remains within the target area AR, the process returns to step S38, and the focus position continues to be adjusted on the object. If the object does not satisfy at least one of the predetermined conditions and being located within the target area AR (step S40; Yes), the focus position control unit 34 removes the focus position from the object (step S42). Thereafter, if the process is not to be ended (step S44; No), the process returns to step S34. If the process is to be ended (step S44; Yes), the process ends.

[0054] As described above, in the second embodiment, the focus position control unit 34 may adjust the focus position on an object that is present in the target area AR and is performing a predetermined motion. The focus position control unit 34 continues to adjust the focus position on the object while the object is performing the predetermined motion, and removes the focus position from the object when the object stops performing the predetermined motion. In this way, by setting the condition for adjusting the focus position as being within the target area AR and also satisfying the predetermined motion, it becomes possible to track an object performing a specific motion and adjust the focus position appropriately. For example, it becomes possible to detect a fall within the target area AR.

[0055] In the second embodiment, the focus position control unit 34 may adjust the focus position to an object that exists in the target area AR and has a predetermined shape. In this way, by setting the condition for adjusting the focus position that the object has a predetermined shape in addition to being within the target area AR, it becomes possible to track an object of a specific shape and adjust the focus position appropriately.

[0056] In the second embodiment, the focus position control unit 34 may adjust the focus position to an object that exists in the target area AR and faces a predetermined direction. In this way, by setting the condition for adjusting the focus position as facing a predetermined direction in addition to being within the target area AR, it becomes possible to track an object facing a specific direction and adjust the focus position appropriately.

[0057] (Third embodiment) Next, a third embodiment will be described. The third embodiment differs from the first embodiment in that a method for adjusting the focal position when multiple objects exist within the target area AR is defined. Explanations of parts of the third embodiment that are common to the first embodiment will be omitted. Note that the third embodiment can also be applied to the second embodiment.

[0058] The object information acquisition unit 32 causes the object position measurement unit 14 to measure the relative position of each object and acquires position information for each object present within the imaging area AR0. The focus position control unit 34 determines whether each object is located within the target area AR based on the position information for each object. If the focus position control unit 34 determines that multiple objects are located within the target area AR at the same time, it switches the focus position so that each object present within the target area AR is in focus. That is, the focus position control unit 34 continues to focus on one object present within the target area AR for a predetermined period of time, then switches the focus position to focus on another object present within the target area AR and continues to focus on that object for a predetermined period of time. The focus position control unit 34 repeats this process until it has finished focusing on all objects present within the target area AR, and then resets the focus position to the object that was initially in focus and continues this process. It should be noted that even during this processing, the focus position control unit 34 continues to determine whether an object is located within the target area AR, and therefore does not adjust the focus position to, for example, an object that is no longer present within the target area AR.

[0059] In this embodiment, the focus position control unit 34 sets the order in which the focus position is switched, i.e., the object to be focused on next, based on the position information of each object present in the target area AR. For example, the focus position control unit 34 may set the order in which the focus position is switched so as to minimize the time required to switch the focus position. That is, since the amount of movement of the optical element 10 required to switch the focus position corresponds to the distance (object distance) between the original position and the target position, the time required to switch the focus position is determined by the object distance, and the shorter the object distance, the shorter the time required to switch. Therefore, the focus position control unit 34 sets the order in which the focus position is switched based on the position information of each object present in the target area AR, i.e., so as to minimize the object distance, in other words, so as to minimize the time required to switch the focus position.

[0060] FIG. 9 is a schematic diagram illustrating an example in which multiple objects exist in the target area. An example of setting the order in which the focus position is switched will be described using FIG. 9. FIG. 9 illustrates an example in which objects Aa, Ab, Ac, and Ad remain positioned within the target area AR. For example, among objects Aa, Ab, Ac, and Ad, the object with the shortest distance from the current focus position (e.g., the object distance from the set position) is set to object Aa. In this case, the focus position control unit 34 minimizes the time required to switch the focus position by switching the focus position to object Aa with the shortest object distance from the current focus position. Next, among objects Ab, Ac, and Ad for which the focus position has not been adjusted so far, the object with the shortest object distance from object Aa is set to object Ab. Therefore, the focus position control unit 34 minimizes the time required to switch the focus position by setting object Ab with the shortest object distance as the next target and switching the focus position from object Aa to object Ab. Next, among objects Ac and Ad for which the focus position has not been adjusted so far, the object with the shortest object distance from object Ab is set to object Ad. Therefore, the focus position control unit 34 sets the object Ad with the smallest object distance as the next object and switches the focus position from object Ab to object Ad. Next, since object Ac is the only object for which the focus position has not been adjusted, the focus position control unit 34 sets object Ac as the next object and switches the focus position from object Ad to object Ac. After that, since there are no more objects for which the focus position has not been adjusted, the focus position control unit 34 switches the focus position to object Aa, for which the focus position was adjusted initially, and continues the same process.

[0061] In this way, the focus position control unit 34 switches the focus position to the object with the smallest object distance among the objects that have not been focused on before. Then, when there are no more objects that have not been focused on before, in other words, when all objects have been focused on, the focus position is adjusted to the object that has been focused on most recently among the objects currently located within the target area AR. However, the method for setting the order in which the focus positions are switched is not limited to the above and may be arbitrary. For example, the focus position control unit 34 may switch the focus position to the object with the longest object distance, or may switch the focus position in order of closest distance from the image capture device 100.

[0062] The predetermined time, which is the time for which the focal position is kept focused on one object, may be set arbitrarily. For example, the predetermined time may be set to the same length for all objects, or the length of the predetermined time may be different for each object. In this case, for example, the focus position control unit 34 may assign importance to each object based on at least one of the object's position information and image data, and the higher the importance, the longer the predetermined time. While any method for assigning importance may be used, for example, the focus position control unit 34 may set the importance of an object to be higher the shorter the distance from the image capture device 100, or the higher the speed at which the object approaches the image capture device 100.

[0063] Furthermore, during a period when multiple objects exist within the target area AR, the focal position control unit 34 may stop switching the focal position to other objects and continue to focus the focal position on one object. For example, when the focal position is focused on a certain object, if the user inputs a command to stop switching the focal position (a command to fix the focal position on that object) to the input unit 16, the focal position control unit 34 stops switching the focal position to other objects and continues to focus the focal position on that object.

[0064] Next, the process flow for setting the focal position described above will be described. FIG. 10 is a flowchart illustrating the process flow for setting the focal position according to the third embodiment. As shown in FIG. 10, the control unit 24 acquires information about the target area AR using the target area acquisition unit 30 (step S50), and acquires object position information using the object information acquisition unit 32 (step S52). The order of steps S50 and S52 may be arbitrary. The control unit 24 determines, using the focus position control unit 34, whether an object is located within the target area AR based on the object position information (step S54). If no object is located within the target area AR (step S54; No), the process returns to step S52 and continues acquiring object position information. On the other hand, if an object is located within the target area AR (step S54; Yes), the focus position control unit 34 determines whether multiple objects are present within the target area AR (step S56). If multiple objects are present within the target area AR (step S56; Yes), the focus position control unit 34 adjusts the focal position to the object with the shortest object distance (step S58). Thereafter, the acquisition of object position information is continued, and it is determined whether or not there is an object within the target area AR (step S60). If there is an object within the target area AR (step S60; No), the process returns to step S56, and the setting of the focal position continues. If there is no object within the target area AR (step S60; Yes), the focal position control unit 34 removes the focal position from the object (step S62), and if the process is not to be ended (step S64; No), the process returns to step S52, and if the process is to be ended (step S64; Yes), the process ends.

[0065] On the other hand, if there are no objects in the target area AR (step S56; No), that is, if there is one object in the target area AR, the focus position is adjusted to that object (step S66). Thereafter, the acquisition of object position information is continued, and it is determined whether there is an object in the target area AR (step S60). If there is an object in the target area AR (step S60; No), the process returns to step S56 and continues setting the focus position. If there is no object in the target area AR (step S60; Yes), the focus position control unit 34 removes the focus position from that object (step S62). If the process is not to be ended (step S64; No), the process returns to step S52. If the process is to be ended (step S64; Yes), the process ends.

[0066] As described above, in the third embodiment, when there are multiple objects in the target area AR, the focus position control unit 34 switches the focus position so that the focus position is adjusted to each object in turn. Therefore, even when there are multiple objects in the target area AR, the focus position can be adjusted appropriately.

[0067] The focal position control unit 34 sets the order in which the focal position is switched depending on the position of each object, so that even when multiple objects exist within the target area AR, the focal position can be adjusted appropriately.

[0068] The focus position control unit 34 sets the order in which the focus position is switched so as to minimize the time required for switching the focus position, and therefore, even when multiple objects exist within the target area AR, the focus position can be adjusted appropriately.

[0069] (Fourth embodiment) Next, a fourth embodiment will be described. The fourth embodiment differs from the first embodiment in that the focal position is not adjusted to an object present within the target area AR, but adjusted to an object when the object moves outside the target area AR. In the fourth embodiment, a description of parts of the configuration common to the first embodiment will be omitted. Note that the fourth embodiment can also be applied to the second and third embodiments.

[0070] The method of setting the focal position in the fourth embodiment can be explained by replacing "inside the target area AR" with "outside the target area AR" in the explanation of the first embodiment. A specific explanation will be given below.

[0071] In the fourth embodiment, the focus position control unit 34 adjusts the focus position on an object that exists within the image capture area AR0 but outside the target area AR, and does not adjust the focus position on an object that exists within the target area AR. The focus position control unit 34 continues to adjust the focus position on the object while the object for which the focus position is adjusted exists within the image capture area AR0 but outside the target area AR. On the other hand, when the object for which the focus position is adjusted no longer exists within the image capture area AR0 but outside the target area AR, that is, when the object moves outside the image capture area AR0 or into the target area AR, the focus position control unit 34 shifts the focus position away from the object and adjusts the focus to a position other than the object.

[0072] Furthermore, it is preferable that the focus position control unit 34 adjusts the focus position for an object that has moved from within the target area AR to outside the target area AR within the imaging area AR0. This is preferable because it makes it possible to adjust the focus position for an object that has moved from a specific area, for example.

[0073] FIG. 11 is a schematic diagram illustrating a method for setting a focal position in the fourth embodiment. An example of the focal position setting described above will be described with reference to FIG. 11. FIG. 11 illustrates an example in which object A moves from position A0b through position A1b to position A2b. Position A0b is within the target area AR, position A1b is within the image capture area AR0 but outside the target area AR, and position A2b is outside the image capture area AR0. In this case, the focus position control unit 34 does not focus on object A when object A is at position A0b, but instead focuses on a set position, for example. Then, the focus position control unit 34 focuses on object A when object A is at position A1b, i.e., when object A moves from within the target area AR to within the image capture area AR0 but outside the target area AR. When object A moves to position A2b, i.e., when object A moves outside the image capture area AR0, the focus position control unit 34 removes the focus from object A and returns the focus to the set position.

[0074] Next, the process flow for setting the focal position described above will be described. FIG. 12 is a flowchart illustrating the process flow for setting the focal position according to the fourth embodiment. As shown in FIG. 12, the control unit 24 acquires information about the target area AR using the target area acquisition unit 30 (step S70), and acquires position information of the object using the object information acquisition unit 32 (step S72). The order of steps S70 and S72 may be arbitrary. The control unit 24 determines, based on the position information of the object, using the focus position control unit 34, whether the object that was present in the target area AR has moved outside the target area AR within the image capture area AR0 (step S74). If the object has not moved outside the target area AR (step S74; No), that is, if the object continues to exist in the target area AR, the process returns to step S72 and continues acquiring position information of the object. On the other hand, if the object has moved outside the target area AR within the image capture area AR0 (step S74; Yes), the focus position control unit 34 adjusts the focal position to the object (step S76). Thereafter, the acquisition of object position information continues, and if the object is within the image capture area AR0 and has not moved from outside the target area AR (step S78; No), that is, if the object remains within the image capture area AR0 but outside the target area AR, the process returns to step S76 and continues to focus on the object. On the other hand, if the object is within the image capture area AR0 and has moved from outside the target area AR (step S78; Yes), that is, if the object has moved outside the image capture area AR or into the target area AR, the focus position control unit 34 removes the focus position from the object (step S80). Thereafter, if the process is not to be ended (step S82; No), the process returns to step S72, and if the process is to be ended (step S82; Yes), the process ends.

[0075] As described above, the imaging device 100 according to the fourth embodiment includes the imaging element 12, the object information acquisition unit 32 that acquires positional information of an object present in the imaging area AR0 of the imaging element 12, and the focus position control unit 34 that controls the focus position of the imaging device 100. The focus position control unit 34 adjusts the focus position on an object that is present outside the target area AR but within the imaging area AR0, continues adjusting the focus position on the object while the object is present outside the target area AR but within the imaging area AR0, and shifts the focus position away from the object when the object moves into the target area AR. The target area AR is the area between a first position AX1, where the distance from the imaging device 100 is a first distance L1, and a second position AX, where the distance from the imaging device 100 is a second distance L2 that is shorter than the first distance L1.

[0076] Here, autofocus imaging devices are required to appropriately adjust the focal position. In contrast, the imaging device 100 according to this embodiment adjusts the focal position to an object existing outside the target area AR, and if the object continues to exist outside the target area AR, continues to adjust the focal position to the object. Therefore, for example, it is possible to continue to adjust the focus to an object that has left the target area, which is an area to be noted. Therefore, according to this embodiment, it is possible to appropriately adjust the focal position.

[0077] Although the embodiments of the present invention have been described above, the embodiments are not limited by the content of these embodiments. Furthermore, the above-described components include those easily conceivable to those skilled in the art, those that are substantially identical, and those within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate, and the configurations of each embodiment can be combined. Furthermore, various omissions, substitutions, or modifications of components can be made without departing from the spirit of the above-described embodiments. Furthermore, while each embodiment has been described with the focus position adjustment operation as a characteristic feature, the focus position adjustment operation may be combined with other operations. For example, the focus position adjustment operation may be combined with a zooming operation. Furthermore, in the description of each embodiment, the focus position adjustment operation may be replaced with other operations. For example, the focus position adjustment operation may be replaced with a zooming operation. Furthermore, in each embodiment, the control unit 24 of the imaging device may send a notification to a predetermined destination via the communication unit 20 when a set condition is met, such as an object entering or leaving a predetermined target area AR or moving in a predetermined direction. The set condition here may refer to, for example, adjusting the focus position to an object when the object moves into the target area AR. [Explanation of symbols]

[0078] 10 Optical Elements 12 Image sensor 14 Object position measurement section 30 Target area acquisition unit 32 Object information acquisition unit 34 Focus position control unit AR target area AR0 imaging area AX1 1st position AX2 2nd position L1 1st distance L2 2nd distance

Claims

1. An imaging device capable of imaging an object, An imaging element; an object information acquisition unit that acquires position information of an object present in an imaging area of ​​the imaging element; a focus position control unit that controls a focus position of the imaging device; and The focus position control unit adjusting the focal position to an object that is outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and that is present within the imaging area; While the object is outside the target area and present within the imaging area, the focal position is kept aligned with the object, and when the object moves into the target area, the focal position is moved away from the object; and the focus position control unit: adjusting the focal position to an object that is present outside the target area and is performing a predetermined motion, continuing to adjust the focal position to the object while the object is performing the predetermined motion, and removing the focal position from the object when the object stops performing the predetermined motion; Imaging device.

2. The imaging device according to claim 1 , wherein when the object moves from inside the target area to outside the target area, the focus position control unit recognizes the object as a target for adjusting the focus position.

3. 3. The imaging device according to claim 1, wherein the focus position control unit controls the focus position by moving a position of an optical element provided in the imaging device.

4. An imaging method for imaging an object, comprising: acquiring position information of an object present in an imaging area; controlling a focus position of the imaging device; In the step of controlling the focal position, adjusting the focal position to an object that is outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and that is present within the imaging area; an imaging method comprising: adjusting the focal position on an object that is outside the target area but present within the imaging area and that is performing a predetermined motion; continuing to adjust the focal position on the object while the object is performing the predetermined motion; and removing the focal position from the object when the object stops performing the predetermined motion.

5. A program for causing a computer to execute an imaging method for imaging an object, acquiring position information of an object present in an imaging area; controlling a focus position of an imaging device; In the step of controlling the focal position, adjusting the focal position to an object that is outside a target area between a first position at a first distance from the imaging device and a second position at a second distance from the imaging device that is shorter than the first distance, and that is present within the imaging area; adjusting the focal position to an object that is outside the target area but present within the imaging area and that is performing a predetermined motion, continuing to adjust the focal position to the object while the object is performing the predetermined motion, and removing the focal position from the object when the object no longer performs the predetermined motion; program.

Images