Imaging device, control method, program, and storage medium

Abstract

To improve the quality of an image by restraining the influence of overshoot on the image.SOLUTION: An imaging device includes an imaging unit containing an optical system and an imaging element for capturing an image obtained by the optical system, a detection unit for detecting a subject from the image captured by the imaging unit, a first drive unit for rotating the imaging unit in a pan direction or a tilt direction, a second drive unit for driving the optical system or the imaging element to shift, and a control unit for controlling the first drive unit and the second drive unit. The control unit determines whether to stop the first drive unit based on the position of the subject detected by the detection unit, and when it is determined to stop the first drive unit, the control unit determines whether to drive the second drive unit based on the drive speed of the first drive unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, there has been a demand for reducing the number of people required in video production, and as a result, there are increasing opportunities to use cameras that can automatically track and capture subjects using pan, tilt, and zoom (hereinafter referred to as PTZ) functions, rather than handheld video cameras that are directly operated by the user.

[0003] Patent Document 1 discloses an automatic tracking device that uses a PTZ function to adjust the shooting range so that the tracking target is included in the shot video. In the device, it is disclosed that the zoom magnification is set according to the tracking speed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2008-219467 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the automatic tracking device disclosed in Patent Document 1, when the tracking speed changes significantly due to a sudden stop of the subject, the tracked target overshoots the target position, resulting in a decrease in image quality.

[0006] Therefore, an object of the present invention is to suppress the influence of overshoot on an image and improve the quality of the image. [Means for solving the problem]

[0007] In order to solve the above problems, an imaging device according to one aspect of the present invention includes an imaging unit including an optical system and an imaging element that captures an image by the optical system, a detection unit that detects a subject from an image captured by the imaging unit, a first drive unit that rotates the imaging unit in a pan direction or a tilt direction, and a second drive unit that drives the optical system or the imaging element to shift. The camera has a control unit that controls the first driving unit and the second driving unit, and the control unit decides whether to stop the first driving unit based on the position of the subject detected by the detection unit, and when it is decided to stop the first driving unit, decides whether to drive the second driving unit based on the driving speed of the first driving unit. Effect of the Invention

[0008] According to the present invention, the influence of overshoot on an image can be suppressed, and the quality of the image can be improved. [Brief description of the drawings]

[0009] [Figure 1] A block diagram showing the device configuration and the functional configuration of an imaging device. [Diagram 2] Illustration of automatic tracking method [Diagram 3] Flowchart of a conventional automatic tracking method [Figure 4] Flowchart showing the operation of the imaging device [Diagram 5] Flowchart showing the operation of the imaging device [Figure 6] Flowchart showing the operation of the imaging device [Figure 7] Flowchart showing the operation of the imaging device [Figure 8] Flowchart showing the operation of the imaging device DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiment for carrying out the present invention will be described in detail with reference to the attached drawings. The embodiment described below is an example of a means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the device to which the present invention is applied and various conditions, and the present invention is not limited to the following embodiment. In addition, a configuration may be made by appropriately combining parts of each embodiment described later.

[0011] <Embodiment 1> (Device configuration) 1(a) is a block diagram showing the configuration of an imaging device according to this embodiment. The imaging device 100 includes an imaging unit 101, a pan-tilt (PT) motor 102, a lens motor 103, an imaging element motor 104, a central processing unit (CPU) 105, a random access memory (RAM) 106, and a read only memory (ROM) 107. The components constituting the imaging device 100 are connected to each other via a bus.

[0012] The imaging unit 101 is composed of an optical system 101a, an imaging element 101b, and an image engine 101c. The optical system 101a is composed of a plurality of lenses, including, for example, a focus lens, a zoom lens, and a shift lens. The optical system 101a collects light from a subject and forms an image on the imaging element 101b. The optical system 101a may be an interchangeable lens, and may not be included in the imaging unit 101. The imaging element 101b captures an image by the optical system 101a. Specifically, the light incident on the imaging element 101b is converted into an electrical signal by photoelectric conversion. The image engine 101c is an image engine that executes image processing for generating image data based on the electrical signal output from the imaging element 101b. The image engine 101c converts, for example, an electrical signal, which is an analog signal, output from the imaging element 101b, into an image signal, which is a digital signal. The image engine 101c is capable of executing known image processing such as sharpness processing, and is also capable of executing detection and recognition processing such as detection processing for detecting a specific subject from the generated image data and subject recognition processing.

[0013] The PT motor (first driving unit) 102 is a motor mechanism that rotates the imaging unit 101 in a pan direction or a tilt direction to change the imaging range of the imaging unit 101. The PT motor 102 changes the imaging range of the imaging unit 101 by driving the imaging unit 101 to change the imaging direction to a pan direction (horizontal direction) or a tilt direction (vertical direction) in accordance with an instruction from a control unit 109 described later.

[0014] The lens motor (second driving unit) 103 is a motor mechanism that changes the optical axis of the optical system 101a and changes the imaging range of the imaging unit 101. Specifically, the lens motor 103 drives at least one lens included in the optical system 101a to change its position. This changes the position of the image formed by the optical system 101a. That is, the imaging range of the imaging unit 101 is changed. More specifically, the lens motor 103 drives at least one lens included in the optical system 101a to shift in a direction perpendicular to the optical axis or tilt in parallel with the shift movement and rotating around an axis intersecting the optical axis. This makes it possible to shift the position of the image formed by the optical system 101a and change the imaging range of the imaging unit 101.

[0015] The image sensor motor (second driving unit) 104 drives the image sensor 101b to change its position. This changes the imaging range of the imaging unit 101. More specifically, the image sensor motor 104 drives the image sensor 101b to shift in a direction perpendicular to the optical axis. This changes the position of the image sensor 101b relative to the position of the image formed by the optical system 101a, so that the imaging range of the imaging unit 101 can be changed. It is noted that at least one of the lens motor 103 and the image sensor motor 104 may be included in the imaging device 100.

[0016] The CPU 105 is a central processing unit for comprehensively controlling each unit constituting the imaging device 100. The CPU 105 reads a program stored in the ROM 107 into the RAM 106, and executes the read program using the RAM 106 as a work area. Among the functional configuration of the imaging device 100 described below, functions realized by software are realized by the CPU 105 executing the program.

[0017] (Functional configuration) Fig. 1(b) is a block diagram showing the functional configuration of the imaging device 100. Configurations that overlap with those in Fig. 1(a) are given the same reference numerals, and descriptions thereof will be omitted. The imaging device 100 has a detection unit 108 and a control unit 109. The detection unit 108 and the control unit 109 are both functions realized by software, and are operated by the CPU 105 executing a program stored in the ROM 107. The function of the detection unit 108 may be realized by the image engine 101c.

[0018] The detection unit 108 detects a subject from an image captured by the imaging unit 101. The subject can be detected by analyzing the image using a known method. The subject to be detected may be a person, an animal, a vehicle, etc., and a specific subject is detected from the image using various algorithms according to the subject to be detected. Note that the subject may be detected using deep learning. The detection unit 108 can output the position of the detected subject on the image. The position to be output may be any coordinate of the subject area on the image, and for example, the center position of the subject area is output.

[0019] The control unit 109 has a function for controlling each unit of the imaging device 100. For example, it executes an automatic tracking process of a detected subject. The control unit 109 controls the driving amount of at least one of the PT motor 102, the lens motor 103, and the image sensor motor 104 so that the position of the subject detected by the detection unit 108 becomes a target position (predetermined position) set in advance on the image. Note that a more detailed operation of the automatic tracking process will be described later in the description of the operation of the imaging device according to this embodiment.

[0020] (Conventional automatic tracking function) Here, a conventional automatic tracking function will be described with reference to Figs. 2 and 3. Fig. 2 shows a setting screen for setting the target position of a subject. First, a user sets a subject target position 201 (predetermined position) so as to obtain a desired composition during automatic tracking. The subject target position 201 indicates the target position of a detected subject, and can be set to any position on an image. In the automatic tracking function, the imaging range is changed so that the detected subject is located at the subject target position 201. The subject target position 201 is set to, for example, the center position of the image.

[0021] Next, the user can set the size of the dead zone 202. The dead zone is an area set to prevent tracking of minute movements of the subject, and indicates a threshold value for the distance (difference) between the target position of the subject and the position of the subject output from the detection unit 108. In the conventional automatic tracking function, the control unit 109 determines that the subject has moved when the subject moves out of the set dead zone 202. In other words, the control unit 109 determines that the subject has moved when the distance (difference) between the target position of the subject and the position of the subject becomes equal to or greater than a predetermined value. When it is determined that the subject has moved, the control unit 109 calculates the drive amount of the PT motor 102 based on the distance (difference) between the subject target position 201 and the position of the subject so that the subject is positioned at the subject target position 201. The calculated drive amount is output to the PT motor 102 to control the PT motor 102. As a result, the imaging range of the imaging unit 101 is changed, and an image in which the subject is positioned at the subject target position 201 is captured.

[0022] FIG. 3 is a flowchart showing the operation of a conventional automatic tracking function.

[0023] In step S301, the distance between the subject target position 201 and the detected subject position is calculated, and the correction amount of the PT motor 102 is calculated based on the calculated distance. Here, the correction amount refers to the drive amount of the PT motor 102 required to capture an image of the detected subject at the set target position. In other words, the correction amount is calculated so that the distance between the detected subject position and the subject target position 201 (predetermined position) becomes small (preferably to become 0).

[0024] In step S302, it is determined whether the distance calculated in step S301 is equal to or greater than a predetermined value. That is, it is determined whether the subject has moved out of the dead zone 202. If the calculated distance is equal to or greater than the predetermined value (Yes in step S302), the process proceeds to step S303. If not (No in step S302), the process returns to step S301, where the distance between the subject target position 201 and the subject position is calculated again, and a correction amount is calculated based on the calculated distance.

[0025] In step S303, the control unit 109 controls the drive amount of the PT motor 102 according to the correction amount. That is, the imaging unit 101 is rotated in the pan direction or tilt direction according to the correction amount so that the subject is positioned at the subject target position 201.

[0026] In steps S304 and S305, similarly to steps S301 and S302, it is determined whether or not the subject has moved out of the dead zone 202 based on the distance between the subject target position 201 and the position of the subject. In other words, it is determined whether or not to stop the PT motor 102 (first driving unit) based on the position of the subject detected by the detection unit 108.

[0027] If it is determined that the subject has not left the dead zone 202 (No in S305), in step S306, the control unit 109 performs processing to stop the PT motor 102, and ends the processing of this flowchart. Note that while the automatic tracking function is enabled, the operation of this flowchart is repeatedly executed, and the imaging range continues to be changed so that the subject to be tracked is located at the subject target position 201.

[0028] (Operation description) Next, the operation of the auto-tracking function of the imaging device according to this embodiment will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing the operation of the auto-tracking function of the imaging device according to this embodiment. The operation shown in this flowchart is executed by the CPU 105 reading out a program stored in the ROM 107 in the imaging device 100.

[0029] Note that the operations from step S401 to step S405 are similar to the operations from step S301 to step S305, and therefore the description thereof will be omitted.

[0030] Here, consider the case where a fast-moving subject suddenly stops. If it is determined in step S405 that the distance is equal to or greater than the threshold, the control unit 109 performs a process of stopping the PT motor 102 (first driving unit) in step S406. However, if the motor suddenly stops (speed is set to 0) from a high speed at that time, there is a possibility that the motor will lose synchronization depending on the type of motor. Therefore, in general, a deceleration process is often provided in the stopping process.

[0031] However, if a stop process is executed when it is determined that the subject has entered the dead zone 202 (No in step S405) as in the conventional method, the subject may overshoot from the subject target position 201 during the deceleration process. Moreover, if the subject moves out of the dead zone 202 due to the overshoot, the PT motor 102 (first driving unit) will be driven again by the automatic tracking function, degrading the image quality.

[0032] Therefore, the operation of the auto-tracking function of the imaging device according to this embodiment is characterized by the stop processing in step S406. Hereinafter, the stop processing of the PT motor 102 (first driving unit) in the auto-tracking function of the imaging device according to this embodiment will be described with reference to Fig. 5. That is, the processing when it is determined in step S405 that the PT motor 102 (first driving unit) should be stopped will be described.

[0033] In step S501, the drive speed of the PT motor 102 is acquired. The drive speed is expressed as an angular velocity per unit time. In step S403, the drive amount of the PT motor 102 is controlled according to the correction amount, and the drive speed is also controlled. The drive speed may be a speed according to the drive amount (for example, the drive speed is increased in proportion to the drive amount), or may be a drive speed preset by the user. In this embodiment, the PT motor 102 rotates at a drive speed according to the drive amount in step S403. Therefore, as the drive amount of the PT motor 102 increases, the drive speed increases, and the possibility of overshoot occurring increases. The drive amount of the PT motor 102 is calculated based on the distance between the position of the subject detected by the detection unit 108 and the subject target position 201. Therefore, in a broader sense, it can be said that the drive speed of the PT motor 102 is determined based on the position of the subject detected by the detection unit 108.

[0034] In step S502, it is determined whether the drive speed of the PT motor 102 is equal to or greater than a threshold value. The threshold value is set to a speed at which overshoot occurs or is noticeable due to deceleration processing. If it is determined that the drive speed of the PT motor 102 is equal to or greater than the threshold value (Yes in step S502), it is determined to drive the lens motor 103 (second drive unit) or the image sensor motor 104 (second drive unit). If the drive speed of the PT motor 102 is less than the threshold value, it is determined not to drive the second drive unit. In this way, when it is determined that the first drive unit is to be stopped, the control unit 109 determines whether to drive the second drive unit based on the drive speed of the first drive unit.

[0035] In step S503, the control unit 109 calculates an overshoot angle based on the driving speed and deceleration information of the PT motor 102. Here, the deceleration information is information determined by the control unit 109, and includes a deceleration indicating how much the driving speed of the PT motor 102 is decelerated per unit time. The deceleration information is information determined when it is determined that the PT motor 102 is to be stopped. In other words, the deceleration information is determined at the timing when it is determined that the distance between the subject target position 201 and the subject position is within a threshold (i.e., the subject has entered the dead zone 202). The deceleration information can be determined based on the magnitude of the driving speed of the PT motor 102. This driving speed is preferably the current driving speed. Therefore, if the current driving speed of the PT motor 102 can be acquired, the deceleration information can be calculated. Note that it is preferable to set an upper limit to the deceleration so that the PT motor 102 does not lose synchronism, and not to decelerate the PT motor 102 to a predetermined deceleration or more. The overshoot angle is the angle of the PT motor 102 corresponding to the amount by which the subject has overshot from the subject target position 201. It can be calculated from the drive speed and deceleration information of the PT motor 102. More specifically, the angle at which the PT motor 102 actually stops can be predicted based on the drive speed of the PT motor 102 and the deceleration per unit time. Thus, the overshoot angle can be calculated by finding the difference with the angle of the PT motor 102 when the subject is positioned at the subject target position 201. Alternatively, a table of the overshoot angle relative to the speed of the PT motor 102 may be stored in ROM 107, and the overshoot angle may be acquired by referring to the table.

[0036] In step S504, the control unit 109 calculates the drive amount of the lens motor 103 (second drive unit) or the image sensor motor 104 (second drive unit) based on the overshoot angle calculated in step S503.

[0037] Here, since the overshoot angle is calculated based on the drive speed of the PT motor 102, it can be said that the drive amount (correction amount) of the lens motor 103 or the image sensor motor 104 is calculated based on the drive speed of the PT motor 102.

[0038] Then, the deviation of the overshoot angle is corrected using either or both of the lens motor 103 and the image sensor motor 104. That is, the correction of the overshoot angle is realized by shifting the optical system 101a or the image sensor 101b.

[0039] When performing correction by shifting the image sensor 101b, it is necessary to change the amount of correction according to the focal length. For example, when the correction angle is θ and the focal length is f, the amount of correction d can be expressed by (Equation 1).

[0040]

number

[0041] The calculation method is merely one example, and various modifications and changes can be made to the calculation method within the scope of the gist.

[0042] Then, in step S505, the control unit 109 stops the PT motor 102. As described above, the shift in the imaging range caused by the overshoot generated by the PT motor 102 is offset by shifting the optical system 101a or the imaging element 101b. This makes it possible to suppress the phenomenon in which the subject shifts from the subject target position 201 due to overshoot, thereby improving the quality of the image.

[0043] In this embodiment, the processing when the PT motor 102 is stopped has been described, but by performing similar processing even when the user changes the drive speed of the PT motor 102, the effect of overshoot on the image can be suppressed. In this case, when the difference between the drive speed designated by the user and the current drive speed is large and deceleration processing is performed (i.e., the designated drive speed is smaller than the current drive speed), the overshoot angle in the deceleration processing is corrected by the lens motor 103 or the image sensor motor 104. This makes it possible to suppress the effect on the image when the drive speed of the PT motor 102 is changed, and improve the quality of the image.

[0044] Now, consider the position of the optical system 101a or the image sensor 101b after the process of step S505 is completed. If this process is completed with the optical system 101a or the image sensor 101b still shifted, these imaging optical systems will be positioned away from the center of the optical axis, and the image quality at the end of this process may be worse than that before the shifting.

[0045] Therefore, in step S505, the PT motor 102 is controlled to rotate by the overshoot angle while returning the shifted optical system 101a or image sensor 101b to its original position. In other words, the second drive unit is driven to return the position of the optical system 101a or image sensor 101b shifted by the second drive unit to the position before the shift. In this case, the first drive unit is driven in the opposite direction to the drive direction of the second drive unit. This makes it possible to suppress the effect of overshoot on the image while suppressing deterioration in image quality.

[0046] <Embodiment 2> In the first embodiment, when the process of stopping the PT motor 102 is executed, the optical system 101a or the image sensor 101b is shifted using the lens motor 103 or the image sensor motor 104. However, in reality, due to the effects of the latency from when the detector 108 detects the subject to when the process of stopping the PT motor 102 is executed, the dead zone 202, and the tracking speed, there may be a difference between the position of the subject at the start of the process of stopping the PT motor 102 and the subject target position 201. If the position of the subject is within the dead zone 202, there is no problem with the automatic tracking function, but ideally it is desirable for the position of the subject to be at the subject target position.

[0047] Therefore, the operation of the automatic tracking function of the imaging device according to this embodiment will be described with reference to Fig. 6. In this embodiment, the amount of correction by the second driving unit is determined based on the overshoot angle of the PT motor 102 and the distance between the detected position of the subject and the subject target position.

[0048] The configuration of the imaging device according to this embodiment is the same as that of the first embodiment, and therefore a description thereof will be omitted. Fig. 6 is a flowchart showing the operation of the stop processing of the PT motor in the automatic tracking function of the imaging device according to this embodiment. The operations up to the stop processing (steps S401 to S406) are the same as those of the first embodiment, and therefore a description thereof will be omitted. The operations shown in this flowchart are also executed by the CPU 105 reading out a program stored in the ROM 107, as in the first embodiment.

[0049] In step S601, similarly to step S501, the drive speed of the PT motor 102 is acquired. The same is true for the determination in step S602; if the drive speed of the PT motor is equal to or greater than the threshold value (Yes in step S602), it is determined that an overshoot will occur in the PT motor 102.

[0050] In step S603, the control unit 109 calculates the distance between the subject target position 201 and the subject position detected by the detection unit 108. In step S604, similar to step S503, the overshoot angle is calculated based on the PT motor 102 driving speed and deceleration information.

[0051] In step S605, the control unit 109 calculates a correction amount for the lens motor 103 or the image sensor motor 104 based on the distance calculated in step S603 and the overshoot angle calculated in step S604. In this embodiment, the correction amount is calculated taking into consideration the distance between the subject target position 201 and the subject position in addition to the overshoot angle. The control unit 109 drives the lens motor 103 or the image sensor motor 104 according to the calculated correction amount. In other words, the control unit 109 shifts and moves the optical system 101a or the image sensor 101b so that the subject position coincides with the subject target position 201.

[0052] According to this embodiment, when the automatic tracking function is stopped (that is, when the process of stopping the PT motor 102 is executed), the difference between the subject target position and the subject position can be reduced while suppressing the effect on the image caused by overshoot of the PT motor 102.

[0053] <Embodiment 3> In this embodiment, a method of selecting a motor to be used for correcting the overshoot angle from the lens motor 103 and the image sensor motor 104 based on the overshoot angle calculated by the control unit 109 will be described.

[0054] 7 is a flowchart showing the process of stopping the PT motor 102 of the imaging device according to this embodiment. The operations in this flowchart other than step S704 are the same as those in the first embodiment, so their explanation will be omitted. The operation of step S704 will be explained in the flowchart shown in FIG.

[0055] As a method for correcting the overshoot angle, two methods have been described: correction by the lens motor 103 and correction by the image sensor motor 104, but the allowable correction angle for each method is different. For correction by the lens motor 103, i.e., correction by shifting the optical system 101a, the allowable correction angle is constant and does not depend on the focal length. However, for correction by the image sensor motor 104, i.e., correction by shifting the image sensor 101b, the allowable correction angle is determined by the limit drive amount and focal length of the image sensor motor 104. If the limit drive amount is d and the focal length is f, the allowable correction angle can be expressed by (Equation 2).

[0056]

number

[0057] In this way, when the focal length is long, the allowable correction angle is narrow, and when the focal length is short, the allowable correction angle is wide. The calculation method is merely an example, and various modifications and changes can be made to the calculation method within the scope of the gist.

[0058] In step S801, it is determined whether or not the overshoot angle calculated in step S703 is within the correction range of the lens motor 103. If it is within the correction range (Yes in step S801), the process proceeds to step S802, and if it is outside the correction range (No in step S801), the process proceeds to step S803.

[0059] In step S802, the lens motor 103 is driven by an overshoot angle.

[0060] In step S803, it is determined whether or not the overshoot angle calculated in step S703 is within the correction range of the image sensor motor 104. If it is within the correction range (Yes in step S803), the process proceeds to step S804, and if it is outside the correction range (No in step S803), the process proceeds to step S805. Note that the correction range by the image sensor motor 104 may be calculated sequentially from the focal length and the driving range of the image sensor.

[0061] In step S804, the image sensor motor 104 is driven by an overshoot angle.

[0062] In step S805, both the lens motor 103 and the image sensor motor 104 are used and driven. In order to reduce the shift in the imaging range caused by overshoot, the maximum driving speed of the PT motor 102 may be calculated in advance from the driving amounts of the lens motor 103 (second driving unit) and the image sensor motor 104 (second driving unit). In this case, the control unit 109 may drive the PT motor 102 at driving speeds within the range up to the maximum driving speed.

[0063] Furthermore, if the drive speed of the PT motor 102 is so fast that the correction of the lens motor 103 and the image sensor motor 104 is insufficient, the second drive unit is driven in the drive direction of the first drive unit while the first drive unit is driving. This makes it possible to increase the amount of correction when correcting the overshoot angle when the PT motor 102 is stopped, and to reduce deviations in the imaging range even at faster drive speeds.

[0064] As described above, according to this embodiment, even if the amount of correction required to correct the overshoot angle exceeds the allowable correction angle of the lens motor 103, the correction can be made using the image sensor motor 104.

[0065] <Other embodiments> The present invention can be realized by a process of reading and executing a program that realizes one or more functions of the above-mentioned embodiment 1. The program is supplied to a system or device via a network or a computer-readable storage medium, and is read and executed by one or more processors in the computer of the system or device. The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0066] 100 Imaging device 101 Imaging unit 102 PT motor 103 Lens motor 104 Image sensor motor 105 CPU 106 RAM 107 ROM 108 Detection unit 109 Control Unit

Claims

1. an imaging unit including an optical system and an imaging element that captures an image by the optical system; a detection unit that detects a subject from an image captured by the imaging unit; A first drive unit that rotates the imaging unit in a pan direction or a tilt direction; a second driving unit that drives the optical system or the image sensor to shift; A control unit that controls the first drive unit and the second drive unit, the control unit determines whether to stop the first driving unit based on the position of the subject detected by the detection unit; an imaging device comprising: an imaging unit that, when it is determined to stop the first driving unit, determines whether or not to drive the second driving unit based on a driving speed of the first driving unit;

2. The imaging device according to claim 1 , wherein the control unit calculates a distance between the position of the subject detected by the detection unit and a predetermined position.

3. The imaging device according to claim 2, characterized in that the control unit decides to drive the first driving unit when the distance is equal to or greater than a threshold value, and decides to stop the first driving unit when the distance is less than the threshold value.

4. The imaging apparatus according to claim 2 , wherein the control unit calculates a correction amount for the first driving unit based on the distance.

5. The imaging apparatus according to claim 4 , wherein the control unit calculates the correction amount so as to reduce the distance.

6. The imaging apparatus according to claim 1 , wherein the control unit determines to drive the second drive unit when the drive speed is equal to or greater than a threshold value.

7. The imaging apparatus according to claim 1 , wherein the control unit calculates a drive amount of the second drive unit based on the drive speed.

8. The imaging device according to claim 1 , wherein the control unit calculates a drive amount of the second drive unit so as to correct a shift in the imaging range of the imaging unit caused by the first drive unit.

9. The imaging device according to claim 1, characterized in that when the control unit drives the second driving unit to return the position of the optical system or the image sensor shifted by the second driving unit to the position before the shift, the control unit drives the first driving unit in a direction opposite to the driving direction of the second driving unit.

10. The first driving unit is a PT motor that rotates the imaging unit in a pan direction or a tilt direction, 10. The imaging device according to claim 9, wherein the second driving section includes at least one of a lens motor that drives the optical system to shift, and an image sensor motor that drives the image sensor to shift.

11. 11. The image pickup apparatus according to claim 10, wherein the lens motor drives at least one lens of the optical system to shift in a direction perpendicular to an optical axis.

12. 11. The imaging apparatus according to claim 10, wherein the imaging element motor drives the imaging element so as to shift the imaging element in a direction perpendicular to an optical axis.

13. A method for controlling an imaging device having an imaging unit including an optical system and an imaging element, comprising: an imaging step of capturing an image by an optical system; a detection step of detecting a subject from the image captured in the imaging step; A control step of controlling a first driving unit that rotates an imaging direction of the imaging unit in a pan direction or a tilt direction and a second driving unit that drives the optical system or the imaging element to shift, In the control step, it is determined whether or not to stop the first driving unit based on the position of the subject detected in the detection step; A control method comprising: when it is decided to stop the first drive unit, determining whether or not to drive the second drive unit based on a drive speed of the first drive unit.

14. A program for causing a computer to execute the control method according to claim 13.

15. A computer-readable storage medium storing the program according to claim 14.

Images