Control apparatus for imaging apparatus, method, and program

Abstract

To complete shot operation for performing autofocus control in a specified movement time to obtain a video focused at the time of reaching movement time.SOLUTION: A control apparatus controls an imaging apparatus 100 comprising driving sections (104, 105) for varying an imaging direction. The control apparatus includes control means (106) for moving the driving sections (104, 105) to a specified position in specified movement time t and controls to perform autofocus control. The control means (106) has, when moving the driving sections (104, 105) to the specified position, low-speed driving period tc2 for reducing the driving speed of the driving sections (104, 105) and performs autofocus control in the low-speed driving period tc2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device, a method, and a program for controlling an imaging device having a drive unit that changes the shooting direction. [Background technology]

[0002] Surveillance systems and video distribution systems use cameras that can be remotely controlled via a network or a dedicated line. Some of these cameras are equipped with a pan drive unit that rotates the camera horizontally and a tilt drive unit that rotates the camera vertically, allowing the camera to freely change the shooting direction. Pan-tilt-zoom (hereinafter also referred to as PTZ) cameras that can pan, tilt, and zoom allow the camera to freely change the shooting direction and shooting angle of view, making it possible to shoot moving subjects. Some cameras also perform autofocus (hereinafter also referred to as AF) control to automatically focus on the subject. PTZ cameras used for broadcasting have a function called shot operation, in which the PTZ position and the time it takes to move to that position are specified, and the PTZs start and stop moving simultaneously to the specified position. When AF control is performed during a shot operation, if the pan drive speed or tilt drive speed exceeds a predetermined speed, the subject of the image captured by the image sensor will move, and AF control using a method for acquiring a contrast evaluation value, for example, may become impossible. If AF control is performed when the pan and tilt are driven to a specified position, a focused image will be obtained after the time required for this AF control has elapsed, and a focused image will no longer be obtainable when the movement time specified in the shot operation is reached.

[0003] Patent Document 1 discloses a method for simultaneously driving and terminating moving parts such as pan, tilt, zoom, and focus by specifying the moving time from the current position to the destination position and calculating the optimal moving speed from the specified time and the moving distance of each of the moving parts. Patent Document 2 also discloses that the camera position and focal distance for the shooting position are stored in advance, and when the camera is panned and tilted to take a shot at the target camera position, the focus lens is set to the target focal position. However, in Patent Documents 1 and 2, when AF control is performed in a shot operation, the focus position is moved to a preset position, and when the subject moves, the focus may go out. When the subject is a moving object such as a person, the distance between the subject and the camera changes from moment to moment, and the process of moving to a preset focus position is likely to result in many cases where the focus is not adjusted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-325710 A [Patent Document 2] Japanese Patent Application Publication No. 9-205573 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above-mentioned points, and aims to complete a shot operation that performs autofocus control within a specified movement time, and to obtain a focused image when the movement time is reached. [Means for solving the problem]

[0006] The control device for an imaging device of the present invention is a control device that controls an imaging device equipped with a drive unit that changes the shooting direction, and is equipped with a control means that controls the drive unit to move to a specified position in a specified movement time and to perform autofocus control, and is characterized in that when moving the drive unit to the specified position, the control means has a low-speed drive period in which the drive speed of the drive unit is reduced, and performs autofocus control during the low-speed drive period. Effect of the Invention

[0007] According to the present invention, a shot operation for executing autofocus control can be completed within a designated movement time, and a focused image can be obtained when the movement time is reached. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of an imaging device according to a first embodiment. [Diagram 2] 1 is an external view of an imaging device according to a first embodiment. [Diagram 3] FIG. 13 is a diagram showing an example of a shot motion control command. [Figure 4] 4 is a flowchart showing a process executed by the imaging device according to the first embodiment. [Diagram 5] 13 is a flowchart showing a process of deriving driving parameters for a shot operation. [Figure 6] FIG. 11 is a characteristic diagram showing acceleration / deceleration control during a shot operation. [Figure 7] 5 is a flowchart showing an AF control process. [Figure 8] 13A and 13B are characteristic diagrams showing modified examples of acceleration / deceleration control of the pan drive unit during a shot operation. [Figure 9] FIG. 11 is a diagram illustrating a configuration of an imaging device according to a second embodiment. [Figure 10] 13 is a flowchart showing a process of deriving a second driving speed based on the angle of view. [Figure 11] 13 is a flowchart showing a process of deriving a second driving speed based on a shutter speed. [Figure 12] 13 is a flowchart showing a process for deriving a low-speed drive period based on an aperture amount. [Figure 13] 11 is a diagram showing an example of the relationship between the aperture amount and the time required for AF control. [Figure 14] FIG. 2 is a diagram illustrating an example of a hardware configuration of a device that functions as a control device of the imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. <First embodiment> The first embodiment will be described with reference to FIGS. Fig. 1 is a diagram showing the configuration of an imaging device 100 according to the first embodiment. Fig. 2 is a diagram showing the external appearance of the imaging device 100 according to the first embodiment, in which (a) is a plan view of the imaging device 100 and (b) is a side view of the imaging device 100. The imaging device 100 is an imaging device known as a network camera or the like, and includes an imaging unit 101, an image processing unit 102, a focus driving unit 103, a pan driving unit 104, a tilt driving unit 105, a system control unit 106, and a communication unit 107.

[0010] The imaging unit 101 includes a lens, an imaging element, and a control circuit for the same, and captures an image of a subject. The imaging unit 101 is electrically connected to an image processing unit 102, receives light from the subject that is imaged by the imaging optical system of the lens, and converts the optical image of the subject into an electrical signal by photoelectric conversion. Under the control of the system control unit 106, the image processing unit 102 acquires the signal photoelectrically converted by the imaging unit 101, and generates image data by performing development processing, compression / encoding processing, etc. The focus driving unit 103 is a driving unit that performs a focus operation to adjust the focus of the imaging unit 101 under the control of the system control unit 106. The focus driving unit 103 includes a mechanism that moves a focus lens included in the imaging unit 101, and an electric motor such as a stepping motor that serves as an actuator.

[0011] The pan driving unit 104 is a driving unit that performs panning of the imaging device 100 under the control of the system control unit 106. The pan driving unit 104 includes a mechanism that performs panning, an electric motor such as a stepping motor that serves as an actuator, and an encoder that detects a pan angle. Tilt driving unit 105 is a driving unit that performs a tilt operation of imaging device 100 under the control of system control unit 106. Tilt driving unit 105 includes a mechanism that performs a tilt operation, an electric motor such as a stepping motor that serves as an actuator, and an encoder that detects the tilt angle.

[0012] The communication unit 107 realizes a network communication function via the network 150. The imaging device 100 can communicate with a client device (not shown) connected to the network 150 via the communication unit 107. The imaging device 100 transmits instructions from the system control unit 106 to the client device via the communication unit 107. The imaging device 100 also receives commands from the client device and transmits responses from the system control unit 106 to the client device via the communication unit 107.

[0013] The system control unit 106 controls the entire imaging device 100. The system control unit 106 transmits and receives commands and responses to a client device (not shown) through the communication unit 107, and controls the imaging device 100. In detail, the system control unit 106 receives a camera control command transmitted from the client device, analyzes the acquired camera control command, and executes processing according to the command. Then, the system control unit 106 transmits a response to the camera control command to the client device. For example, the system control unit 106 controls the image processing unit 102 based on an image quality adjustment command transmitted from the client device. The system control unit 106 also controls the pan driving unit 104 and the tilt driving unit 105 based on a control command transmitted from the client device. The system control unit 106 also controls the focus driving unit 103 to execute AF (autofocus) control for focusing on a subject captured by the imaging unit 101.

[0014] As shown in FIG. 2, the imaging device 100 includes a bottom case 110, a turntable 111, a camera head support 112, and a camera head 113. The bottom case 110 serves as a base for the entire imaging device 100 . The turntable 111 is installed on the bottom case 110 . The camera head support pillar 112 is a support pillar that supports the camera head 113. The camera head support pillar 112 is disposed coaxially with the central axis C of the turntable 111, and its base end is supported at the center position of the turntable 111. The camera head support pillar 112 also supports the camera head 113 at its upper end. When the turntable 111 rotates, the camera head support pillar 112 rotates around the central axis C of the turntable 111, thereby performing a panning operation of the imaging device 100. The camera head 113 is a unit that includes the imaging unit 101. The camera head 113 swings about an axis perpendicular to the central axis C to perform a tilt operation of the imaging device 100.

[0015] The pan driving unit 104 is built into the bottom case 110 or the turntable 111. That is, a mechanism for performing panning, an actuator, and an encoder, which constitute the pan driving unit 104, are installed inside the bottom case 110 or the turntable 111. In this embodiment, as shown in FIG. 2(a), panning can be performed in the range of -175 degrees to +175 degrees. Note that the movable range of the panning is an example and is not limited thereto. The tilt drive unit 105 is built into the camera head support 112 or the camera head 113. That is, a mechanism for performing tilt operation, an actuator, and an encoder, which constitute the tilt drive unit 105, are installed inside the camera head support 112 or the camera head 113. In this embodiment, as shown in FIG. 2(b), the direction perpendicular to the central axis C is defined as 0 degrees, and the bottom case 110 side is defined as the negative direction, and the tilt operation can be performed in a range from -45 degrees to +90 degrees. Note that the movable range of the tilt operation is an example and is not limited to this. In this way, the imaging device 100 can perform panning and tilting operations to change the imaging direction and capture images. Although it has been described above that pan driving unit 104 is built into bottom case 110 or turntable 111, and tilt driving unit 105 is built into camera head support 112 or camera head 113, the present invention is not limited to this and may have other configurations. Furthermore, pan driving unit 104 and tilt driving unit 105 may be configured as a pan / tilt driving unit that performs panning and tilting operations of imaging device 100.

[0016] In the imaging device 100 according to this embodiment, the pan driving unit 104 and the tilt driving unit 105 are moved to preset designated positions (pan designated position, tilt designated position) within a designated movement time t, and a shot operation is performed to execute AF control. Fig. 3 is a diagram showing an example of a control command (shot operation control command) 300 indicating a shot operation instruction of the imaging device 100. In Fig. 3, "0100" of a command identifier 301 is a command instructing a shot operation. Parameter 302 is a parameter indicating a designated pan position of the shot operation, and specifies the pan position by an angle value. Parameter 303 is a parameter indicating a designated tilt position of the shot operation, and specifies the tilt position by an angle value. Parameter 304 is a parameter indicating a movement time t of the shot operation, and specifies the movement time t in seconds. Here, an example is shown in which the designated position and the movement time t of the shot motion are designated as parameters in one command, but this is not limiting. For example, a command for registering the designated position and the movement time t of the shot motion and a command for instructing the shot motion may be separated.

[0017] The shot operation performed by the imaging device 100 according to the first embodiment will be described below. First, an overview of the control of the pan driving unit 104 during a shot operation will be described with reference to Fig. 6. Fig. 6 is a characteristic diagram showing acceleration / deceleration control of the pan driving unit 104 during a shot operation, where the horizontal axis is time and the vertical axis is driving speed. In Fig. 6, t is a designated movement time, t a1 is the acceleration period, t c1 is the constant speed driving period, t d1 is the first deceleration period, tc2 is the low-speed drive period, t d2 indicates the second deceleration period. Also, a1 is the acceleration, v1 is the first drive speed, d1 is the first deceleration, v2 is the second drive speed, and d2 is the second deceleration. When the pan driving unit 104 is moved to the designated pan position during a moving time t, the pan driving unit 104 is driven at a first driving speed v1 during a constant speed driving period t. c1 After that, a low-speed driving period t c2 In the example of FIG. 6, the low-speed driving period t c2 Then, the pan driving unit 104 is driven at a constant speed of the second driving speed v2. Then, during the low-speed driving period t c2 AF control is performed.

[0018] The same applies to the control of the tilt driver 105 during the shot operation. That is, when the tilt driver 105 is moved to the tilt designated position in the moving time t, the tilt driver 105 is driven at a constant speed v1 during a constant speed driving period t. c1 After that, a low-speed driving period t c2 The low-speed driving period t c2 Then, the tilt driver 105 is driven at a constant speed of the second driving speed v2. Then, during the low-speed driving period t c2 AF control is performed. In this case, for example, the pan driving unit 104 and the tilt driving unit 105 have a movement time t and an acceleration period t a1 , constant speed driving period t c1 , the first deceleration period t d1 , low speed driving period t c2 , the second deceleration period t d2 are made common (the same time). Then, the pan driving unit 104 and the tilt driving unit 105 appropriately set the acceleration a1, the first driving speed v1, the first deceleration d1, the second driving speed v2, and the second deceleration d2 (details will be described later). This allows a shot operation to be performed in which the driving of the pan driving unit 104 and the tilt driving unit 105 starts and ends simultaneously during the movement time t. The pan driving unit 104 and the tilt driving unit 105 have a movement time t and a low-speed driving period t c2 is common, and the acceleration period t a1 , constant speed driving period t c1 , the first deceleration period t d1 , the second deceleration period t d2 Even in this case, by appropriately setting the acceleration a1, the first driving speed v1, the first deceleration d1, the second driving speed v2, and the second deceleration d2 in the pan driving unit 104 and the tilt driving unit 105, respectively, it is possible to perform a shot operation in which the driving of the pan driving unit 104 and the tilt driving unit 105 starts and ends simultaneously during the movement time t.

[0019] Fig. 4 is a flowchart showing the process executed by the imaging apparatus 100. The flowchart in Fig. 4 starts when the system control unit 106 receives a shot operation control command. In step S401, the system control unit 106 starts a low-speed driving period t immediately before the shooting operation is stopped so that AF control is possible. c2 Set the low-speed drive period t c2 is common to the pan driving unit 104 and the tilt driving unit 105. In this embodiment, the low speed driving period t c2 is a predetermined fixed time, and is derived as follows: c2 is derived based on the time required for AF control, including the time required for moving the focus lens to perform focus search for the subject after the subject included in the designated position of the shot appears and the time required for moving the focus lens to the in-focus position. c2 is, for example, 2 seconds. In addition, the low-speed driving period t c2 The time required for AF control may be set longer by adding the time for maintaining the focused state. This allows the focused state to be maintained for a certain period of time during driving before the shot operation is stopped for the sake of image quality, rather than achieving the focused state just before the shot operation is stopped.

[0020] In step S402, the system control unit 106 starts the low-speed driving period t c2 The second driving speed v2 of each of the pan driving unit 104 and the tilt driving unit 105 in the AF control mode is set. In this embodiment, the second driving speed v2 is a fixed driving speed determined in advance, and is derived as follows. The second driving speed v2 of the pan driving unit 104 is set as a driving speed at which a contrast evaluation value required for AF control can be obtained, for example, based on the moving speed on the image due to panning. When the horizontal angle of view of the imaging unit 101 is 100 degrees, the pan driving speed v [degrees / second] for keeping the moving speed of the subject on the image within 1 [% / second] as an AF controllable index is obtained by the formula (1), and this is set as the second driving speed v2. Note that the derivation method described here is an example, and the driving speed at which AF control is possible may be derived according to the AF control method and other camera control characteristics. v=100 1 / 100=1 (1)

[0021] In step S403, the system control unit 106 derives driving parameters for the shot operations of the pan driving unit 104 and the tilt driving unit 105. Details of step S403 will be described later with reference to FIG. In step S404, the system control unit 106 determines whether the low-speed driving period t c2 Based on the second driving speed v2 and the driving parameters derived in step S403, the pan driving unit 104 and the tilt driving unit 105 start driving.

[0022] In step S405, the system control unit 106 uses the second driving speed v2 set in step S402 as a threshold value and monitors the driving speed of the pan driving unit 104 and the driving speed of the tilt driving unit 105. If the driving speed of the pan driving unit 104 and the driving speed of the tilt driving unit 105 become equal to or lower than the respective threshold values, the process proceeds to step S406. In step S406, the system control unit 106 executes AF control by controlling the focus driving unit 103. Details of step S406 will be described later with reference to FIG. In step S407, the system control unit 106 monitors the completion of driving of the pan driving unit 104, the tilt driving unit 105, and the focus driving unit 103. When the driving of the pan driving unit 104, the tilt driving unit 105, and the focus driving unit 103 is completed, that is, when the AF control is completed and the pan driving unit 104 and the tilt driving unit 105 are moved to the designated positions, this process ends.

[0023] Fig. 5 is a flowchart showing a process of deriving driving parameters for a shot operation. The flowchart in Fig. 5 is executed as a subroutine when the system control unit 106 executes the process of step S403 in Fig. 4. The pan driving unit 104 will be described below, but the tilt driving unit 105 is similar. In step S501, the system control unit 106 derives the movement angle of the pan driving unit 104 based on the current position of the pan driving unit 104 and the designated pan position designated in the shot operation. For example, if the current position of the pan driving unit 104 is 40 degrees and the designated pan position is 90 degrees, the movement angle of the pan driving unit 104 is 90-40=50 degrees It becomes.

[0024] In step S502, the system control unit 106 calculates the movement angle calculated in step S501, the movement time t designated in the shot operation, and the low-speed drive period t set in step S401. c2 Based on the second driving speed v2 set in step S402, the constant speed driving period t c1 A first driving speed v1 for driving at a constant speed is derived. Here, with reference to FIG. 6, a method for deriving the first driving speed v1 will be described. The movement time t designated in the shot operation is, for example, 10 seconds (hereinafter, "second" is also referred to as "s"). The movement angle of the pan driving unit 104 is 50 degrees derived in step S501. The low-speed driving period t c2 is 2 seconds set in step S401. The second driving speed v2 is 1 degree / second set in step S402. In addition, the acceleration period t a1 , the first deceleration period t d1, the second deceleration period t d2 is preset as a fixed time, for example, t a1 is 0.5 seconds, t d1 is 0.5 seconds, t d2 These times are set according to the driving characteristics of acceleration and deceleration, such as the load on the pan driving unit 104 and the torque of the actuator.

[0025] In this case, the constant speed driving period t c1 is expressed by equation (2). From equation (2), t c1 =10-(0.5+0.5+2+0.1)=6.9 seconds. t c1 =t-(t a1 +t d1 +t c2 +t d2 ) (2)

[0026] The movement angle l of the pan driving unit 104 is expressed by the first driving speed v1, the second driving speed v2, and the acceleration period t a1 , constant speed driving period t c1 , the first deceleration period t d1 , low speed driving period t c2 , the second deceleration period t d2 Using this, it is expressed as equation (3).

[0027]

number

[0028] By solving the first drive velocity v1 from the equation (3), the equation (4) is obtained. From the equation (4), the first drive velocity v1 is approximately 6.446 degrees / second.

[0029]

number

[0030] Returning to the explanation of FIG. 5, in step S503, the system control unit 106 derives the acceleration a1 and decelerations d1 and d2 of the pan driving unit 104. Here, a method for deriving the acceleration a1 and the decelerations d1 and d2 will be described with reference to FIG. Acceleration a1 [degrees / s 2 ] is expressed by equation (5). From equation (5), the acceleration a1 is approximately 12.892 degrees / s 2 become.

[0031]

number

[0032] Also, the first deceleration d1 [deg / s 2 From equation (6), the first deceleration d1 is approximately 10.892 degrees / s 2 become.

[0033]

number

[0034] Also, the second deceleration d2 [degrees / s 2 From equation (7), the second deceleration d2 is 10 degrees / s 2 become.

[0035]

number

[0036] The system control unit 106 performs acceleration / deceleration control of the pan drive unit 104 as shown in FIG. 6 based on the first drive speed v1, second drive speed v2, acceleration a1, first deceleration d1, and second deceleration d2 set in this manner.

[0037] Fig. 7 is a flowchart showing the AF control process, which is executed as a subroutine when the system control unit 106 executes the process of step S406 in Fig. 4. In step S701, the system control unit 106 starts a focus search for searching for a focusing position by moving the focus lens within a predetermined range using the focus driving unit 103. In step S702, the system control unit 106 acquires a contrast evaluation value of the image data at each position of the moved focus lens. The image processing unit 102 extracts high-frequency components from the image data to derive a contrast evaluation value indicating the contrast state of the subject image, and transmits the contrast evaluation value to the system control unit 106.

[0038] In step S703, the system control unit 106 determines whether the focus lens has moved within the focus search range and acquisition of the contrast evaluation value at each position has been completed. If acquisition of the contrast evaluation value has been completed, the system control unit 106 proceeds to step S704. If acquisition of the contrast evaluation value has not been completed, the system control unit 106 returns to step S702, continues processing, and performs focus search within a predetermined range. In step S704, the system control unit 106 derives the position with the highest contrast evaluation value from the contrast evaluation values ​​at each position of the focus lens, and sets this position as the in-focus position.

[0039] In step S705, the system control unit 106 moves the focus lens to the in-focus position derived in step S704, and ends this process. In this embodiment, the contrast AF method is described as the AF control method, but this is only an example and other methods may be used. For example, a phase difference AF method may be adopted in which a dedicated sensor for detecting a phase difference is used to obtain the amount of focus deviation, the in-focus position is calculated from the obtained amount of deviation, and the focus lens position is moved.

[0040] As described above, when the pan driving unit 104 and the tilt driving unit 105 are moved to their designated positions, the driving speeds of the pan driving unit 104 and the tilt driving unit 105 are reduced during the low-speed driving period t c2 and the low speed driving period t c2In this way, the shot operation for performing the AF control can be completed within the designated movement time t, and a focused image can be obtained when the movement time t is reached.

[0041] In this embodiment, as shown in FIG. c2 In the above, the pan driving unit 104 is driven at a constant speed of the second driving speed v2, but the present invention is not limited to this. For example, as shown in FIG. c2 Then, the pan driver 104 may be driven to decelerate using the second drive speed v2 as the deceleration start speed. 8 is a characteristic diagram showing a modified example of the acceleration / deceleration control of the pan driving unit 104 during a shot operation, where the horizontal axis is time and the vertical axis is driving speed. In FIG. 8, t is a designated movement time, t a1 is the acceleration period, t c1 is the constant speed driving period, t d1 is the first deceleration period, t c2 indicates the low-speed drive period. Also, a1 is the acceleration, v1 is the first drive speed, d1 is the first deceleration, v2 is the second drive speed, and d2 is the second deceleration. The same applies to the control of tilt drive unit 105.

[0042] In this case, the process of deriving the driving parameters for the shot operation in FIG. 5 is as follows. In step S502, the system control unit 106 calculates the movement angle calculated in step S501, the movement time t designated in the shot operation, and the low-speed drive period t set in step S401. c2 Based on the second driving speed v2 set in step S402, the constant speed driving period t c1 A first driving speed v1 for driving at a constant speed is derived. Here, with reference to FIG. 8, a method for deriving the first driving speed v1 will be described. The movement time t designated in the shot operation is, for example, 10 seconds. The movement angle of the pan driving unit 104 is 50 degrees derived in step S501. The low-speed driving period t c2 is 2 seconds set in step S401. The second driving speed v2 is 1 degree / second set in step S402. In addition, the acceleration period t a1 , the first deceleration period t d1 is preset as a fixed time, for example, t a1 is 0.5 seconds, t d1 These times are set according to the driving characteristics of acceleration and deceleration, such as the load on the pan driving unit 104 and the torque of the actuator.

[0043] In this case, the constant speed driving period t c1 is expressed by equation (8). From equation (8), t c1 =10-(0.5+0.5+2)=7 seconds. t c1 =t-(t a1 +t d1 +t c2 ) ···(8)

[0044] The movement angle l of the pan driving unit 104 is expressed by the first driving speed v1, the second driving speed v2, and the acceleration period t a1 , constant speed driving period t c1 , the first deceleration period t d1 , low speed driving period t c2 Using this, it is expressed as equation (9).

[0045]

number

[0046] By solving the first drive speed v1 from the formula (9), the formula (10) is obtained. From the formula (10), the first drive speed v1 becomes 6.5 degrees / second.

[0047]

number

[0048] In addition, in the present embodiment, an example of trapezoidal acceleration / deceleration control has been shown, but the present invention is not limited to this. For smoother control, acceleration / deceleration control may be performed in an S-shape with a predetermined curvature.

[0049] <Second embodiment> The second embodiment will be described with reference to Fig. 9 to Fig. 13. In the following, the same components as those of the imaging device 100 according to the first embodiment will be denoted by the same reference numerals, and the description will be omitted, and the differences from the first embodiment will be mainly described. In the first embodiment, the low-speed driving period t c2 The second drive speed v2 is set to a fixed value so that AF control is possible. In contrast, in the second embodiment, the low-speed driving period t c2 In this example, the second driving speed v2 is derived and set according to the angle of view, the shutter speed, and the aperture value. c2 By deriving the second driving speed v2, it is possible to obtain a focused image when the movement time t is reached, even if the camera control state changes.

[0050] (Example of setting the second drive speed v2 according to the angle of view) 9 is a diagram showing the configuration of an imaging device 100 according to the second embodiment. In addition to the configuration described in the first embodiment, the imaging device 100 according to the second embodiment includes a zoom driving unit 108. By controlling the zoom driving unit 108, the angle of view of the image captured by the imaging unit 101 can be changed. The zoom driving unit 108 is a driving unit that performs a zoom operation under the control of the system control unit 106. The zoom driving unit 108 includes a mechanism that moves the zoom lens included in the imaging unit 101, and an electric motor such as a stepping motor that serves as an actuator. In this way, in an imaging device with an optical zoom function, the movement speed on the image relative to the actual pan and tilt drive speed differs depending on the angle of view, and even at the same drive speed, the movement speed on the image becomes relatively faster as the angle of view becomes more telephoto. When AF control is performed using an image captured by the imaging unit 101, the drive speed at which AF control is possible also changes depending on the movement speed on the image. Therefore, in the second embodiment, the second drive speed v2 is set based on the angle of view that changes due to the optical zoom function. Specifically, when the angle of view is on the wide-angle side, the second drive speed v2 is set fast, and when the angle of view is on the telephoto side, the second drive speed v2 is set slow. In this way, by setting an appropriate second drive speed v2, it is possible to obtain a focused image when the movement time t is reached, even if the angle of view changes.

[0051] Fig. 10 is a flowchart showing a process of deriving the second driving speed v2 based on the angle of view. The flowchart in Fig. 10 is executed as a subroutine when the system control unit 106 executes the process of step S402 in Fig. 4. Although the pan driving unit 104 will be described below, the tilt driving unit 105 is similarly executed. In step S1001, the system control unit 106 acquires the current angle of view.

[0052] In step S1002, the system control unit 106 derives a second driving speed v2 based on the current angle of view. If the horizontal angle of view is h [degrees] and the pan driving speed is v [degrees / second], the movement speed a [% / second] on the captured image is expressed by equation (11). a=v / h (11) By solving equation (11) for the pan drive speed v, which becomes the movement speed a on the image, equation (12) is obtained. v = h a (12) For example, assume that the horizontal angle of view acquired in step S1001 is 60 degrees. In this case, the pan drive speed v for keeping the moving speed on the image within 1% / sec, which is an index for AF control, is given by: v=60·1 / 100=0.6[degrees / second] This is set as the second drive speed v2. Note that the derivation method described here is just one example, and the second drive speed v2 at which AF control is possible may be obtained depending on the AF control method and other camera control characteristics.

[0053] (Example of setting the second drive speed v2 according to the shutter speed) In the imaging device 100, the shutter speed is controllable, the exposure time of the imaging element can be changed, and the brightness of the image captured by the imaging unit 101 and the expression of the subject movement can be changed. Changing the shutter speed changes the effect of subject image blur caused by panning and tilting, and the slower the shutter speed, the greater the subject image blur caused by panning and tilting. When AF control is performed using the image captured by the imaging unit 101, the driving speed at which AF control is possible will also change depending on the extent of this image blur. Therefore, in the second embodiment, the second drive speed v2 is set based on the shutter speed. Specifically, when the shutter speed is on the high speed side, the second drive speed v2 is set high, and when the shutter speed is on the low speed side (slow shutter side), the second drive speed v2 is set low. By setting an appropriate second drive speed v2, it is possible to obtain a focused image when the movement time t is reached, even if the shutter speed changes.

[0054] Fig. 11 is a flowchart showing a process of deriving a second driving speed v2 based on a shutter speed. The flowchart in Fig. 11 is executed as a subroutine when the system control unit 106 executes the process of step S402 in Fig. 4. The pan driving unit 104 will be described below, but the tilt driving unit 105 is similarly executed. In step S1101, the system control unit 106 obtains the current shutter speed.

[0055] In step S1102, the system control unit 106 derives a second drive speed v2 based on the current shutter speed. If the horizontal angle of view is h [degrees], the horizontal pixels are n [pixels], the pan drive speed is v [degrees / second], and the shutter speed is s [seconds], the pixel change amount x [pixels] during the shutter speed and pan operation is expressed by Equation (13). x=v·s·n / h (13) By solving the pan drive speed v that results in the pixel change amount x from equation (13), equation (14) is obtained. v = (h x) / (s n) (14) For example, assume that the horizontal angle of view is 60 degrees, the horizontal pixels are 1920, and the shutter speed acquired in step S1001 is 1 / 20 seconds. In this case, the pan drive speed v for confining the amount of blur caused by panning during the shutter speed to one pixel as an index for AF control is given by (14) as follows: v=(60·1) / {(1 / 20)·1920}=0.625[degrees / second] This is set as the second drive speed v2. Note that the derivation method described here is just one example, and the second drive speed v2 at which AF control is possible may be obtained depending on the AF control method and other camera control characteristics.

[0056] (The low-speed driving period t c2 Example of setting In the imaging device 100, the imaging unit 101 has an aperture and can change the aperture amount, thereby changing the amount of exposure to the imaging element per unit time. This makes it possible to change the image expression, such as the brightness and depth of field, of the image captured by the imaging unit 101. Changing the aperture value changes the depth of field of the image captured by the imaging unit 101. When AF control is performed using the image captured by the imaging unit 101, the focus search range changes depending on the depth of field, and the time required for AF control also changes. Therefore, in the second embodiment, the low-speed driving period t c2 Specifically, when the throttle amount is on the open side, the low-speed driving period t c2 When the aperture is small, the low-speed driving period t c2 This shortens the appropriate low-speed drive period t c2 By setting t, even if the aperture value changes, a focused image can be obtained when the movement time t is reached.

[0057] FIG. 12 shows the slow drive period t c212 is a flowchart showing a process for deriving the vector .DELTA..times ... In step S1201, the system control unit 106 acquires the current aperture amount.

[0058] In step S1202, the system control unit 106 determines the low-speed driving period t c2 FIG. 13 shows an example of the relationship between the aperture value and the time required for AF control. As shown in FIG. 13, the more the aperture value is opened, the longer the time required for AF control. These values ​​are obtained from the lens characteristics and AF control characteristics, and are recorded in advance in a non-volatile memory as a table. For example, if the aperture value acquired in step S1201 is I6, the time required for AF control when the aperture value is I6 is derived as T6 from the relationship in FIG. 13, as an index for AF controllability. This is referred to as the low-speed drive period t c2 Set as. The derivation method described here is an example, and the AF controllable low-speed drive period t c2 It is sufficient to ask for the following.

[0059] In the above description, the low-speed drive period t c2 , the second driving speed v2 is set, but the low-speed driving period t c2 , a second driving speed v2 may be set. Also, parameters other than the angle of view, shutter speed, and aperture value may be referred to. For example, in the contrast AF method, it is possible to perform focusing with high accuracy even in a dark environment, but in a dark environment, the time required for AF control is longer than in a bright environment. Therefore, in a dark environment, the low-speed driving period t c2 In bright environments, the low-speed driving period t c2 may be shortened.

[0060] In this embodiment, the imaging device 100 itself functions as a control device of the imaging device to which the present invention is applied, but for example, the control device of the imaging device to which the present invention is applied may be configured as a device separate from the imaging device. 14 shows an example of the hardware configuration of a device that functions as a control device for an imaging device to which the present invention is applied. The computer device includes a CPU 1, a memory 2, a storage device 3, an input device 4, and an output device 5, which are interconnected by a bus 6. The CPU 1 executes the programs stored in the storage device 3. This executes the function of the control means of the present invention. The memory 2 temporarily stores the programs and data that the CPU 1 reads from the storage device 3. The memory 2 is also used as an area for the CPU 1 to execute various programs. The storage device 3 stores an operating system (OS), various programs, and various data. The input device 4 is a functional unit that accepts input from an operator, and may be, for example, a keyboard or a mouse. The output device 5 executes output of information input by the input device 4 and the execution results of the programs executed by the CPU 1.

[0061] Although the present invention has been described above with reference to the embodiments, the above embodiments are merely illustrative of the specific examples of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from its technical concept or main features. (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0062] The disclosure of this embodiment includes the following configuration. (Configuration 1) A control device for controlling an imaging device having a driving unit that changes the shooting direction, a control means for controlling the driving unit to move to a designated position within a designated movement time and to execute autofocus control; The control device for an imaging device, characterized in that the control means has a low-speed drive period in which the drive speed of the drive unit is reduced when moving the drive unit to the specified position, and performs autofocus control during the low-speed drive period. (Configuration 2) 2. The control device for an imaging device according to configuration 1, wherein the control means sets the low-speed drive period so as to enable autofocus control. (Configuration 3) 3. The control device for an imaging device according to configuration 1 or 2, wherein the control means sets a second drive speed of the drive section during the low-speed drive period so as to enable autofocus control. (Configuration 4) The low-speed driving period is provided after a constant-speed driving period in which the driving unit is driven at a first driving speed, The control device for an imaging device according to configuration 3, wherein the control means derives the first drive speed based on the specified position, the movement time, the low-speed drive period, and the second drive speed. (Configuration 5) 5. The control device for an imaging device according to configuration 3 or 4, wherein the control means drives the drive section at a constant speed at the second drive speed during the low-speed drive period. (Configuration 6) 5. The control device for an imaging device according to configuration 3 or 4, wherein the control means drives the drive section at a deceleration start speed equal to the second drive speed during the low-speed drive period. (Configuration 7) The control means deriving the second drive speed based on an angle of view that changes due to an optical zoom function of the imaging device; 7. The control device for an imaging device according to any one of configurations 3 to 6, wherein when the angle of view is on the wide-angle side, the second driving speed is made faster, and when the angle of view is on the telephoto side, the second driving speed is made slower. (Configuration 8) The control means deriving the second drive speed based on a shutter speed of the imaging device; The control device for an imaging device according to any one of configurations 3 to 7, wherein when a shutter speed is on the high speed side, the second drive speed is set to be high, and when the shutter speed is on the low speed side, the second drive speed is set to be low. (Configuration 9) The control means deriving the low-speed drive period based on an aperture amount of an aperture provided in the imaging device; 9. The control device for an imaging device according to any one of configurations 3 to 8, wherein when the aperture amount is on the open side, the low-speed drive period is made longer, and when the aperture amount is on the small aperture side, the low-speed drive period is made shorter. [Explanation of symbols]

[0063] 100: imaging device, 101: imaging section, 102: image processing section, 103: focus driving section, 104: pan driving section, 105: tilt driving section, 106: system control section, 107: communication section, 108: zoom driving section

Claims

1. A control device for controlling an imaging device having a drive unit that changes the imaging direction, a control means for controlling the driving unit to move to a designated position within a designated movement time and to execute autofocus control; The control device for an imaging device, characterized in that the control means has a low-speed drive period in which the drive speed of the drive unit is reduced when moving the drive unit to the specified position, and performs autofocus control during the low-speed drive period.

2. 2. The control device for an imaging device according to claim 1, wherein the control means sets the low-speed drive period so as to enable autofocus control.

3. 3. The control device for an imaging device according to claim 1, wherein the control means sets the drive unit to drive at a second drive speed slower than the first drive speed during the low-speed drive period so as to enable autofocus control.

4. the low-speed driving period is provided after a constant-speed driving period in which the driving unit is driven at the first driving speed, 4. The control device for an imaging device according to claim 3, wherein the control means derives the first drive speed based on the specified position, the movement time, the low-speed drive period, and the second drive speed.

5. 4. The control device for an imaging device according to claim 3, wherein the control means drives the drive unit at the second drive speed during the low-speed drive period.

6. 4. The control device for an imaging device according to claim 3, wherein the control means drives the drive unit at a deceleration speed during the low-speed drive period, with the second drive speed as a deceleration start speed.

7. The control means deriving the second drive speed based on an angle of view that changes due to an optical zoom function of the imaging device; 4. The control device for an imaging device according to claim 3, wherein the second driving speed is increased when the angle of view is on the wide-angle side, and the second driving speed is decreased when the angle of view is on the telephoto side.

8. The control means deriving the second drive speed based on a shutter speed of the imaging device; 4. The control device for an imaging device according to claim 3, wherein the second drive speed is set to a high speed when the shutter speed is on the high speed side, and the second drive speed is set to a low speed when the shutter speed is on the low speed side.

9. 3. The control device for an imaging device according to claim 2, wherein the low-speed drive period is derived based on the time required for autofocus control, including the time it takes for the focus lens to move to a focus search for the subject after the subject included in the designated position of the shot operation appears and the time it takes for the focus lens to move to a focus position.

10. 10. The control device for an imaging device according to claim 9, wherein the low-speed drive period is set to a period of time required for the autofocus control plus a predetermined time.

11. The control means deriving the low-speed drive period based on the aperture size of an aperture provided in the imaging device; 4. The control device for an imaging device according to claim 3, wherein the low-speed drive period is made longer when the aperture amount is on the widest side, and the low-speed drive period is made shorter when the aperture amount is on the smallest side.

12. A control method for controlling an imaging device having a drive unit that changes the imaging direction, comprising: a control step of controlling the driving unit to move to a designated position within a designated movement time and to execute autofocus control; a control method for an imaging device, characterized in that the control step includes a low-speed drive period in which the drive speed of the drive unit is reduced when the drive unit is moved to the specified position, and autofocus control is performed during the low-speed drive period.

13. A program for controlling an imaging device having a drive unit that changes the imaging direction, causing the computer to function as a control means for controlling the driving unit to move to a designated position within a designated movement time and for controlling the driving unit to execute autofocus control; The control means, when moving the drive unit to the specified position, has a low-speed drive period in which the drive speed of the drive unit is reduced, and performs autofocus control during the low-speed drive period.

Images