Image capture device, image capture device control method, and program

Abstract

To provide a technique capable of precisely locating an imaging direction on a target position intended by a user.SOLUTION: The imaging apparatus includes an imaging means for capturing an image and control means for executing a process for controlling an imaging direction of the imaging means. The control means controls the timing to start a stopping process for stopping the control of the imaging direction in accordance with the speed at which the imaging direction is changed when controlling the imaging direction to a target location.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for controlling an imaging device. [Background technology]

[0002] There are technologies for controlling the imaging direction of an imaging device that captures an image. In such technologies, it is important to control the imaging direction and then stop the control of the imaging direction accurately at a desired position so that the user can capture an image of the location intended by the user.

[0003] Patent document 1 describes a method in which a drive signal is started to be output to a pan motor to drive the pan motor, and when the rotation angle of the pan motor reaches a target rotation angle, the output of the drive signal to the pan motor is stopped. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-131184 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, a process is executed to stop control of the imaging direction when the imaging direction reaches the target position, and therefore, particularly when the imaging direction is controlled at a high speed, the imaging direction may stop at a position significantly different from the target position.

[0006] Therefore, an object of the present invention is to provide a technique that can accurately position the imaging direction at a target position intended by a user. [Means for solving the problem]

[0007] In order to solve the above problem, the imaging device according to the present embodiment includes an imaging unit that captures an image, and a control unit that executes direction designation control, which is a process for controlling the imaging direction of the imaging unit, and when the control unit controls the imaging direction to a target position, A braking distance corresponding to the current change speed is determined based on a function of the change speed of the imaging direction and the braking distance, and the determined braking distance is calculated. The timing to start a stop process for stopping the control of the imaging direction is controlled based on the current position of the imaging means and the target position. [Effects of the Invention]

[0008] According to the present invention, the imaging direction can be accurately positioned at a target position intended by the user. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a system configuration. [Figure 2] FIG. 1 is a diagram illustrating an external view of an imaging device. [Figure 3] FIG. 2 is a diagram showing functional blocks of the imaging device and the camera platform. [Figure 4] 10 is a flowchart showing the flow of processing for stopping control of the imaging direction. [Figure 5] FIG. 10 is a diagram illustrating an example of a function of a change speed and a braking distance. [Figure 6] 10 is a flowchart showing the flow of processing for stopping control of the imaging direction. [Figure 7] FIG. 2 is a diagram illustrating the hardware configuration of each device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples and are not limited to the configurations shown in the drawings.

[0011] (Embodiment 1) 1 is a diagram showing the system configuration of this embodiment, which includes an image capturing device 1000, a camera platform 2000, a client device 3000, and a network 4000.

[0012] The imaging device 1000 and the client device 3000 are connected to each other so that they can communicate with each other via a network 4000. The network 4000 is realized by a plurality of routers, switches, cables, etc. that comply with a communication standard such as ETHERNET (registered trademark).

[0013] The network 4000 may be realized by the Internet, a wired LAN (Local Area Network), a wireless LAN, a WAN (Wide Area Network), or the like.

[0014] In response to a request from the client device 3000, the imaging device 1000 can transmit captured image data and the like to the client device 3000 via the network 4000. The imaging device 1000 may also actively transmit image data and the like to the client device 3000 to which it is connected in advance. Here, the client device 3000 is an information processing device configured by a general terminal device such as a personal computer (PC), a smartphone, or a tablet PC. The client device 3000 controls the imaging direction and image quality of the imaging device 1000. The client device 3000 may also directly control the imaging direction of the camera platform 2000. The client device 3000 may also be a dedicated controller device for operating the imaging device 1000 and the camera platform 2000. Additionally, the client device 3000 may be a control device that controls settings and controls of the imaging device 1000, such as focus and white balance, and controls the camera platform 2000.

[0015] The camera platform 2000 is a device that controls the pan and tilt of the imaging device 1000 via the imaging device 1000 in response to a request from the client device 3000. Communication between the imaging device 1000 and the camera platform 2000 may be achieved using EIA (Electronic Industries Association) communication standards RS-232C, RS-422A, or RS-485, or other communication standards. The imaging device 1000 and the camera platform 2000 may be provided in the same housing; in other words, the imaging device 1000 itself may have a drive unit for controlling the imaging direction.

[0016] 2 and 3, the imaging device 1000 and the camera platform 2000 will be described. FIG. 2 is an example of an external view of the imaging device 1000 and the camera platform 2000 in this embodiment. The imaging device 1000 is a device that captures images, and can change the zoom value by controlling a lens driver 1001. The camera platform 2000 in this embodiment can change the imaging direction of the imaging device 1000 to a pan direction (horizontal direction) 2003 and a tilt direction (vertical direction) 2004 by controlling a pan driver 2001 and a tilt driver 2002.

[0017] Next, the functions of the imaging device 1000 and the camera platform 2000 will be described with reference to Fig. 3. Of the functional blocks of the imaging device 1000 according to this embodiment, the functions of the image processing unit 1012, lens control unit 1013, storage unit 1014, communication unit 1015, system control unit 1016, etc. are realized as follows: That is, the functions are realized by a CPU (Central Processing Unit) 700 of the imaging device 1000 executing a computer program stored in a ROM (Read Only Memory) 720 of the imaging device 1000, which will be described later with reference to Fig. 7.

[0018] The imaging unit 1011 is composed of an imaging element (not shown), such as a CCD (charge coupled device) sensor or a CMOS (complementary metal oxide semiconductor) sensor. The imaging unit 1011 photoelectrically converts an object image formed through a lens to generate an electrical signal. The image processing unit 1012 performs image processing, such as converting the electrical signal photoelectrically converted by the imaging unit 1011 into a digital signal and compression encoding, to generate image data. Note that the number of image data generated is not limited to one; multiple image data sets with different resolutions and video qualities may be generated simultaneously. The generated image data is also transmitted to the system control unit 1016. The lens driving unit 1001 is composed of a driving system for a focus lens and a zoom lens, and its operation is controlled by the lens control unit 1013. The lens control unit 1013 controls the lens driving unit 1001 based on instructions transmitted from the system control unit 1016. The image processing unit 1012 also transmits focus movement information and zoom movement information to the system control unit 1016.

[0019] The storage unit 1014 stores various setting information, etc. The system control unit 1016 analyzes the transmitted camera control command and performs processing according to the command. For example, the system control unit 1016 instructs the image processing unit 1012 to adjust image quality and instructs the lens control unit 1013 to control zoom and focus, according to the acquired camera control command. The system control unit 1016 also acquires image data generated by the image processing unit 1012 and transmits it to the communication unit 1017. Furthermore, the system control unit 1016 converts the pan / tilt control command received by the communication unit 1015 into a camera platform control command and transmits it to the communication unit 1015.

[0020] The communication unit 1015 transmits image data transmitted from the system control unit 1016 to the client device 3000. It also receives various setting commands and camera control commands transmitted from the client device 3000 and transmits them to the system control unit 1016. It also transmits responses of the imaging device 1000 to commands transmitted from the client device 3000 to the client device 3000. It also transmits pan head control commands transmitted from the system control unit 1016 to the communication unit 2012 of the pan head 2000.

[0021] The pan drive unit 2001 of the camera platform 2000 is composed of a mechanical drive system that performs panning and a motor that serves as a drive source, and drives to control rotational drive for rotating the imaging direction of the imaging device 1000 in a pan direction 2003. The operation of the pan drive unit 2001 is controlled by a system control unit 2011. The tilt drive unit 2002 is composed of a mechanical drive system that performs tilting and a motor that serves as a drive source, and drives to control rotational drive for rotating the imaging direction of the imaging device 1000 in a tilt direction 2004. The operation of the tilt drive unit 2002 is controlled by the system control unit 2011.

[0022] The system control unit 2011 analyzes the transmitted camera head control command and instructs the pan driver 2001 and tilt driver 2002 to perform pan and tilt operations. It also obtains the current angle data of the pan driver 2001 and tilt driver 2002 and transmits it to the communication unit 2012.

[0023] The communication unit 2012 transmits a pan head control command transmitted from the communication unit 1015 of the imaging device 1000 to the system control unit 2011. The communication unit 2012 also receives current angle data of the pan driver 2001 and tilt driver 2002 transmitted from the system control unit 2011 and transmits the data to the communication unit 1015 of the imaging device 1000. Note that the imaging device 1000 and the pan head 2000 may be housed in the same housing; in other words, the imaging device 1000 may have the pan driver 2001 and the tilt driver 2002.

[0024] There are two main types of control methods for the camera platform: position specification control, which specifies the pan angle and tilt angle and controls the imaging direction to match the specified pan angle and tilt angle, and direction specification control, which specifies the direction of imaging movement.

[0025] Assume that a user requests position specification control to a target position for a camera platform that does not support position specification control but does support direction specification control. In this case, in this embodiment, when the system control unit 1016 operates the camera platform to the target position specified by the current position acquisition command and direction specification control, it starts the process of stopping the direction specification control a braking distance before the target position, which corresponds to the operation speed of the camera platform. Note that if the user does not specify a speed for controlling (changing) the imaging direction, the camera platform is assumed to operate at maximum speed.

[0026] 4 and 5, a method for controlling the timing for starting processing to stop control of the imaging direction in this embodiment will be described. It is assumed that, prior to the processing shown in Fig. 4, a pan / tilt position that serves as a target position for the imaging direction is specified by a user at the client 3000, and information on the target position is transmitted from the client 3000 to the imaging device 1000 via the network 4000. The processing flow shown in Fig. 4 is executed by the functional blocks shown in Fig. 3, which are implemented by the CPU 700 of the imaging device 1000 executing a computer program stored in the ROM 720 of the imaging device 1000, for example.

[0027] In S4001 shown in FIG. 4, the system control unit 1016 acquires the most recently acquired current pan / tilt position stored in the memory unit 1014 and determines whether the current position is equal to the target position. Note that even if the current position and the target position do not exactly match, the system control unit 1016 determines that the current position is equal to the target position if the difference between the current position and the target position is less than a threshold value. If it is determined that they are equal in S4001 (No in S4001), the pan / tilt control ends. On the other hand, if it is determined that the current position and the target position are not equal (Yes in S4001), the process proceeds to S4002. Note that the current position used in S4001 may be the stop position from the previous control stored in the memory unit 1015. Alternatively, the system control unit 1016 may periodically send a current position acquisition command to the pan / tilt head 2000 and use the current pan / tilt position obtained as a response thereto as the current position used in S4001.

[0028] In S4002, the system control unit 1016 of the imaging device 1000 sends a direction specification control start processing command to the system control unit 2011 of the camera platform 2000 via the communication units 1015 and 2012. At this time, the system control unit 1016 determines the pan / tilt direction to the target position, and sends a direction specification control start processing command such that pan and tilt are controlled in the determined direction. To determine the pan / tilt direction to the target position, the following processing is executed, for example. That is, to reach the target position from the current position, the system control unit 1016 determines whether the pan direction 2003 is the shortest, either rightward or leftward, and similarly determines whether the tilt direction 2004 is the shortest, either upward or downward. Then, the system control unit 1016 specifies the shortest direction between right and left as the pan direction 2003, and similarly specifies the shortest direction between up and down as the tilt direction 2004, and transmits a processing command to start direction specification control so that control will be performed in the specified direction.

[0029] Next, in S4003, the system control unit 1016 of the imaging device 1000 transmits a current position acquisition command requesting the current pan / tilt position to the system control unit 2011 via the communication unit 1015 and the communication unit 2012. Then, the system control unit 1016 acquires the current position transmitted from the camera platform 2000 as a response to the current position acquisition command.

[0030] Next, in S4004, the system control unit 1016 determines a braking distance corresponding to the operating speed (change speed) of the current imaging direction based on a braking distance function (described later) and determines whether the sum of the current position and the braking distance exceeds the target position. If the sum of the current position and the braking distance does not exceed the target position (No in S4004), in other words, if the target position is not reached even when the braking distance is added to the current position, proceed to S4003 and execute the process of S4003 again. If the sum of the current position and the braking distance exceeds the target position (Yes in S4004), in other words, if the target position is reached when the braking distance is added to the current position, proceed to S4005. Note that the conditional expression in S4004 may be the sum of the current distance and the braking distance plus an allowable stopping error. The operating speed of the platform may be stored as specified when the start command for direction specification control was issued in S4002, or may be estimated from the current position used in S4001 and the current position acquired in S4003.

[0031] In S4005, the system control unit 1016 transmits a stop processing command to the system control unit 2011 to request that control of the imaging direction be stopped, via the communication unit 1015 and the communication unit 2012. Then, in response to receiving the stop processing command, the camera platform 2000 ends pan / tilt control.

[0032] FIG. 5 shows an example of a braking distance function (hereinafter, "braking distance function") corresponding to the operation speed of the camera platform, which is referenced by the system control unit 1016 when acquiring the braking distance in S4004. As shown in FIG. 5(a), different braking distances are assigned depending on the operation speed of the camera platform (in other words, the speed at which the imaging direction is changed). For example, the faster the operation speed of the camera platform (the speed at which the imaging direction is changed), the larger the braking distance value. Conversely, the slower the operation speed of the camera platform (the speed at which the imaging direction is changed), the smaller the braking distance value. That is, a first braking distance is assigned to a first speed at which the imaging direction is changed, and a second braking distance greater than the first braking distance is assigned to a second speed at which the imaging direction is changed that is faster than the first speed. Note that the braking distance function may be determined by storing a table of camera platform operation speeds and braking distances in advance in the storage unit 1015, as shown in FIG. 5(a), and then the system control unit 1016 may refer to this table in S4004. Furthermore, when the camera platform or lens attached to the imaging device is changed, the system control unit 1016 may sample the braking distance actually required for the camera platform operating speed and dynamically update the function table as shown in FIG. 5(b). In this case, for example, when controlling the imaging direction at a first change speed, the system control unit 1016 determines the distance from when a stop command is sent to when the imaging direction actually stops, and samples the determined distance as the braking distance for the first change speed. Similarly, a new braking distance function may be generated by sampling the braking distance for a plurality of different change speeds, such as a second change speed and a third change speed, as shown in FIG. 5(b). Note that different braking distance functions may be stored in the memory unit 1015 for each of the pan direction 2003 and the tilt direction 2004. In this case, the system control unit 1016 determines the braking distance corresponding to the current change speed of the imaging direction in the pan direction 2003 by referring to the braking distance function for the pan direction 2003. Furthermore, the system control unit 1016 refers to the braking distance function for the tilt direction 2004 to determine the braking distance according to the speed at which the current imaging direction is changed in the tilt direction 2004 .Furthermore, different braking distance functions may be stored for the right and downward directions in the pan direction 2003 and the upward and downward directions in the tilt direction 2004.

[0033] As described above, the imaging device of this embodiment, when controlling the imaging direction of the imaging device to a target position, specifies a braking distance according to the speed at which the imaging direction is changed, and executes processing to stop control of the imaging direction when the imaging device has reached the target position by the specified braking distance. In this way, the imaging device of this embodiment controls the timing to start processing to stop control of the imaging direction. Here, if processing to stop control of the imaging direction is executed when the imaging direction has reached the target position, for example, a lag may occur in sending the stop command, and it may take a certain amount of time from the start of the stop processing to the actual stop, resulting in the imaging device stopping at a position significantly deviated from the target position. On the other hand, this embodiment solves the above problem by specifying a braking distance according to the speed at which the imaging direction is changed, and executing processing to stop when the imaging device has reached the target position by the braking distance.

[0034] Furthermore, in a case where the imaging direction of an imaging device is controlled by a camera platform, the communication between the camera platform and the imaging device is slow, and it takes time to send and receive control commands to control the camera platform and to obtain the current position of the camera platform. Even in such a case, if a process to stop the control of the imaging direction is executed when the target position is reached, a lag occurs in the sending and receiving of the stopping command, and it takes time from the start of the stopping process to the actual stopping, which may result in the imaging device stopping at a position significantly different from the target position. However, as described above, this problem can be solved according to this embodiment. In other words, according to this embodiment, the imaging direction can be stopped more accurately at the target position intended by the user.

[0035] (Embodiment 2) In the second embodiment, when a difference occurs between the stop position and the target position, the speed at which the image capture direction is changed is changed and the image capture direction is again controlled to the target position. Note that the following mainly describes the differences from the first embodiment, and the same reference numerals are used to designate the same or equivalent components and processes as those in the first embodiment, and redundant explanations will be omitted.

[0036] Fig. 6 is a flowchart showing the flow of processing for stopping the imaging direction in this embodiment. Note that the processing of the flow shown in Fig. 6 is executed by the functional blocks shown in Fig. 3 which are realized by the CPU 700 of the imaging device 1000 executing a computer program stored in the ROM 720 of the imaging device 1000, for example.

[0037] In S6001, the system control unit 1016 acquires the most recently acquired current pan / tilt position stored in the storage unit 1014 and determines whether the current position is equal to the target position. Note that even if the current position and the target position do not exactly match, the system control unit 1016 determines that the current position is equal to the target position as long as the difference between the current position and the target position is less than a threshold. If it is determined that they are equal in S6001 (No in S6001), the pan / tilt control ends. On the other hand, if it is determined that the current position and the target position are not equal (Yes in S6001), the process proceeds to S6002. In S6002, the system control unit 1016 stores the current pan / tilt position in the storage unit 1014 as a start position. Note that the flow from S6003 to S6006 is the same as S4002 to S4005 described in the first embodiment, and therefore description thereof will be omitted.

[0038] In S6007, the system control unit 1016 sends a current position acquisition command to the system control unit 2011 via the communication unit 1015 and the communication unit 2012, and the process proceeds to S6008. In S6008, the system control unit 1016 acquires the start position of the pan / tilt operation from the memory unit 1014, and determines whether it has moved from the start position. If the start position and the current position are the same, it is determined that the camera head has not moved due to the direction specification control, and the pan / tilt control ends. If the start position and the current position are different, the process proceeds to S6009. Even if the current position and the target position do not exactly match, they are determined to be the same position if the difference between the start position and the current position is less than a predetermined value.

[0039] Next, in S6009, the system control unit 1016 obtains the previous position from the memory unit 1014 and determines whether the pan head has completely stopped. If the previous position and the current position are different, it is determined that the pan head is still in a stopped state, and the process proceeds to S6007. If the previous position and the current position are the same, it is determined that the pan head has stopped operating, and the process proceeds to S6010. Note that even if the current position and the previous position do not exactly match, they are determined to be in the same position as long as the difference between the previous position and the current position is less than a predetermined value.

[0040] Next, in S6010, the system control unit 1016 obtains information about the allowable error from the memory unit 1014 and determines whether the current position of the pan / tilt head is located within the allowable error from the target position. If the allowable error is exceeded (No in S6010), the process proceeds to S6011. If the allowable error is within the allowable error (Yes in S6011), the pan / tilt control ends.

[0041] In S6011, the system control unit 1016 changes the operation speed of the camera platform to a speed slower than the currently set operation speed, and then proceeds to S6002. Note that the changed speed for each loop count may be determined in advance, or the speed during the previous direction specification control may be decelerated in a geometric progression according to the loop count. Also, a maximum number of loops may be determined.

[0042] As described above, in this embodiment, even if an error occurs between the stop position and the target position when panning and tilting to the target position using direction specification control, the operation speed of the camera platform is changed and the stopping process is started a braking distance before the target position according to the changed operation speed. In this way, it is possible to improve the accuracy of stopping the imaging direction at the target position desired by the user.

[0043] (Other embodiments) Next, the hardware configuration of the imaging device 1000 for realizing each function of each embodiment will be described with reference to Fig. 7. Note that although the hardware configuration of the imaging device 1000 will be described in the following explanation, it is assumed that the camera platform 2000 and the client device 3000 are also realized by the same hardware configuration.

[0044] The imaging device 1000 of this embodiment includes a CPU 700 , a RAM 710 , a ROM 720 , an HDD 730 , and an I / F 740 .

[0045] The CPU 700 is a central processing unit that controls the imaging device 1000. The RAM 710 temporarily stores computer programs executed by the CPU 700. The RAM 710 also provides a work area used by the CPU 700 when executing processing. The RAM 710 also functions as, for example, a frame memory or a buffer memory.

[0046] The ROM 720 stores programs and the like that are used by the CPU 700 to control the image capturing apparatus 1000. The HDD 730 is a storage device that records image data and the like.

[0047] The I / F 710 communicates with external devices via the network 140 in accordance with TCP / IP, HTTP, or the like.

[0048] Although the above-described embodiment describes an example in which the CPU 700 executes the processing, at least a part of the processing by the CPU 700 may be executed by dedicated hardware. For example, the processing of reading program code from the ROM 720 and loading it into the RAM 710 may be executed by a DMA (Direct Memory Access) that functions as a transfer device.

[0049] The present invention can also be realized by a process in which one or more processors read and execute a program that realizes one or more functions of the above-described embodiments. The program may be supplied to a system or device having a processor via a network or a storage medium. The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions of the above-described embodiments. Each unit of the imaging device 1000 may be realized by hardware shown in FIG. 7, or by software.

[0050] Note that one or more functions of the imaging device 1000 according to the above-described embodiment may be implemented by another device. For example, one or more functions of the imaging device 1000 according to the embodiment may be implemented by another device.

[0051] Although the present invention has been described above with reference to the embodiments, the above embodiments merely illustrate specific examples of how the present invention can be implemented, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be implemented in various forms without departing from the technical concept or main features of the present invention. For example, combinations of the embodiments are also included in the disclosure of this specification. [Explanation of symbols]

[0052] 1000 Imaging Device 1016 System control unit 2000 Pan head 2011 System Control Unit 3000 client devices 4000 Network

Claims

1. an imaging means for capturing an image; a control unit that executes a direction designation control that is a process for controlling the imaging direction of the imaging unit; an imaging device characterized in that, when controlling the imaging direction to a target position, the control means specifies a braking distance corresponding to a current change speed of the imaging direction based on a function of the change speed and a braking distance, and controls a timing to start a stop process for stopping control of the imaging direction based on the specified braking distance, the current position of the imaging means, and the target position.

2. 2. The imaging device according to claim 1, further comprising an acquisition unit for acquiring a current position of the imaging unit.

3. The imaging device according to claim 1 or 2, characterized in that the control means determines a braking distance corresponding to a current change speed based on a function of the change speed of the imaging direction in the pan direction and the braking distance, and a function of the change speed of the imaging direction in the tilt direction and the braking distance.

4. The imaging device according to any one of claims 1 to 3, characterized in that the control means generates the new function by identifying the distance to stop when the imaging direction is changed at different change speeds.

5. The imaging device according to any one of claims 1 to 4, characterized in that the control means starts the stopping process when the target position is reached when a braking distance corresponding to the change speed is added to the current position of the imaging means.

6. The imaging device according to any one of claims 1 to 5, characterized in that, when a difference between a stop position after control of the imaging direction has been stopped by the stop processing and the target position exceeds an allowable error, the control means changes the change speed to a low speed and re-executes the process of controlling the imaging direction to the target position.

7. 2. The imaging device according to claim 1, wherein the stopping process is a process of transmitting a command to a camera platform having a drive unit for changing the imaging direction, requesting the camera platform to stop controlling the imaging direction.

8. A control method for controlling an imaging device having an imaging means for capturing an image, comprising: an acquisition step of acquiring the image; a control step of executing a direction designation control which is a process for controlling the imaging direction of the imaging means, a control method characterized in that, in the control step, when the imaging direction is controlled to a target position, a braking distance corresponding to the current change speed of the imaging direction is specified based on a function of the change speed of the imaging direction and the braking distance, and the timing to start a stop process for stopping the control of the imaging direction is controlled based on the specified braking distance, the current position of the imaging means, and the target position.

9. A program that causes a computer to function as each of the means of the imaging device according to any one of claims 1 to 7.

Images