JP2011223084A - Imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate roughness of a position in a changeable imaging range by a pan head mechanism in an imaging system.SOLUTION: The imaging system includes: imaging apparatuses 10 and 30 for imaging a subject in the imaging range to form an image; first imaging range moving means 20 for changing directions of the imaging apparatuses so as to move the imaging range; second imaging range moving means 31 capable of moving the imaging range with a smaller moving amount than the minimum moving amount in the imaging range by the first imaging range moving means; and control means 11 for operating the first imaging range moving means and the second imaging range moving means in accordance with an instruction to move the imaging range.

Description

  The present invention relates to an imaging system capable of panning and tilting an imaging apparatus.

In the imaging system as described above, the imaging device is supported by the pan head mechanism, and the orientation of the imaging device, that is, the imaging range by the imaging device is changed by operating the pan head mechanism in the pan direction or the tilt direction by the motor. (Moved).

  However, if a stepping motor is used as the motor, the changeable position of the image pickup range becomes discontinuous due to the stop position resolution (minimum movement amount) of the stepping motor, and the image pickup range is set between two adjacent changeable positions. Cannot be set. For this reason, when the imaging range is moved following a slowly moving subject, the imaging range may suddenly move greatly and the subject may fall out of the imaging range.

  By driving the stepping motor by the driving method disclosed in Patent Document 1, it is possible to solve the above-described problem by making the stop position resolution of the stepping motor higher (finer).

JP 2003-224997 A

However, even if the stepping motor is driven by the driving method disclosed in Patent Document 1, it is difficult to accurately move and stop the imaging range to each changeable position due to rotation unevenness caused by a manufacturing error of the stepping motor.

  The present invention provides an imaging system capable of eliminating the roughness of the position of the imaging range that can be changed by the pan head mechanism.

An imaging system as one aspect of the present invention includes an imaging device that captures an image of a subject within an imaging range and generates an image, and a first imaging range moving unit that changes the orientation of the imaging device so as to move the imaging range. The second imaging range moving means capable of moving the imaging range with a movement amount smaller than the minimum moving amount of the imaging range by the first imaging range moving means, and the first in response to an instruction to move the imaging range And an imaging range moving means and a control means for operating the second imaging range moving means.

According to the present invention, even if the position of the imaging range changed (moved) by the operation of the first imaging range moving unit is rough, the position of the imaging range is changed more finely by the operation of the second imaging range moving unit. be able to. Therefore, as compared with the conventional imaging system having only the first imaging range moving means, finer position setting of the imaging range, slower movement of the imaging range, smooth follow-up imaging for a moving subject, and the like are possible. Become.

1 is a block diagram showing a configuration of an imaging system (surveillance camera system) that is Embodiment 1 of the present invention. FIG. 3 is a diagram for explaining movement of an imaging range by a pan head mechanism in the imaging system according to the first embodiment. FIG. 3 is a diagram for explaining movement of an imaging range by a pan head mechanism and an optical image stabilization mechanism in the imaging system of Embodiment 1. The block diagram which shows the structure of the imaging system (surveillance camera system) which is Example 2 of this invention. FIG. 6 is a diagram for explaining electronic image stabilization processing in the imaging system according to the second embodiment. FIG. 6 is a diagram for explaining movement of an imaging range by a pan head mechanism and electronic image stabilization processing in the imaging system of Embodiment 2. Explanatory drawing when moving the imaging range in the tilt direction as in the first and second embodiments.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a surveillance camera system as an imaging system that is Embodiment 1 of the present invention. The surveillance camera system of the present embodiment includes a pan / tilt operation of a camera (imaging device) by a pan head mechanism (first imaging range moving means) and an optical image stabilization mechanism (second imaging range moving means) in the camera. The imaging range is moved in combination with the image shift operation by.

  The surveillance camera system includes a camera configured by the camera body 10 and the lens unit 30, and a pan head mechanism 20 that supports the camera via a support unit 60.

  The camera body 10 includes a microcomputer 11, a vibration gyro 12, a camera signal processing unit 13, a video encoder 14, a remote control sensor 15, an image sensor 16, and a timing generator 17.

  The vibration gyro 12 is an angular velocity detector for detecting vibration applied to the camera, and detects vibration in the pitch direction (vertical direction) and the yaw direction (horizontal direction).

  The imaging element 16 is a photoelectric conversion element such as a CCD sensor or a CMOS sensor that photoelectrically converts a subject image formed by a photographing optical system in the lens unit 30 and outputs an imaging signal. The photographing optical system includes a variable apex angle prism (VAP) 31 that is an optical element of an optical image stabilization mechanism, a variable power lens 32, a diaphragm 33, and a focus lens 34. The photographing optical system forms a subject image that is an optical image of a subject within an imaging range that is an object field range that is captured by a camera.

  The variable apex angle prism 31 is configured by enclosing a transparent liquid between two transparent flat plates, and changes the angle (vertical angle) formed by the transparent flat plate to change the subject image formed by the photographing optical system in the pitch direction. And shift in the yaw direction. The lens unit 30 includes a VAP actuator 36 that operates the variable apex angle prism 31 (changes the apex angle), a VAP driver 40 that drives the VAP actuator 36, and an apex that detects the apex angle of the variable apex angle prism 31. An angle sensor 35 is provided.

  Further, the lens unit 30 is provided with a zoom motor 37 and a focus motor 39 that move the zoom lens 32 and the focus lens 34 in the optical axis direction, and a zoom driver 41 and a focus driver 43 that drive the motors 37 and 39. It has been. Further, the lens unit 30 is provided with an aperture motor 38 that operates the aperture 33 and an aperture driver 42 that drives the aperture motor 38. The zoom driver 41, the aperture driver 42, and the focus driver 43 drive the zoom motor 37, the aperture motor 38, and the focus motor 39 in accordance with a drive command from the microcomputer 11.

  In the camera body 10, the camera signal processing unit 13 performs video signal processing such as color correction, gamma correction, and effect processing on the imaging signal output from the imaging device 16 to generate a video signal (image). The video encoder 14 encodes the video signal generated by the camera signal processing unit 13 and outputs the encoded video signal to an external camera control device 70 described later.

  The timing generator 17 controls the readout timing of the imaging signal from the imaging device 16 and the transfer timing to the camera processing circuit unit 13.

  The external camera control device 70 is configured by a personal computer or the like, and communicates with the microcomputer 11 via a communication line such as the Internet, LAN, and wireless and the external communication interface 15 in the camera body 10. The external camera control device 70 transmits an instruction for causing the monitoring camera system to perform various operations in accordance with the operation of the operator. This instruction includes an instruction to move the imaging range.

  The microcomputer 11 controls the operation of each part of the camera system such as the camera signal processing unit 13, the vibration gyro 12, the external communication interface 15, and the pan head mechanism 20.

  The microcomputer 11 integrates the vibration detection signal from the vibration gyro 12 to calculate the magnitude and direction of the vibration, and operates the VAP actuator 36 via the VAP driver 40 according to the calculation result. Thereby, the apex angle of the variable apex angle prism 31 changes, and the image blur of the subject image is reduced.

  Further, the microcomputer 11 causes the pan / tilt mechanism 20 to perform a pan / tilt operation in response to an imaging range movement instruction transmitted from the external camera control device 70 in response to an operator pan / tilt operation in the external camera control device 70. . Specifically, the microcomputer 11 calculates the rotation amounts (operation amounts) of the pan motor 21 and the tilt motor 22 based on the information on the target position of the imaging range included in the instruction to move the imaging range. Then, a drive command is given to the pan motor driver 23 and the tilt motor driver 24 so that the motors 21 and 22 are rotated by the calculated rotation amount. In this way, the microcomputer 11 operates the pan head mechanism 20 to move the imaging range (changes the position of the imaging range).

  Here, both the pan motor 21 and the tilt motor 22 are configured by stepping motors. The pan motor driver 23 and the tilt motor driver 24 generate a drive pulse signal having the number of pulses corresponding to the rotation amount calculated based on the target position described above in response to a drive command from the microcomputer 11. To give. The microcomputer 11 can detect the rotation amount of these motors 21 and 22 by counting the number of pulses of the drive pulse signal given to the pan motor 21 and the tilt motor 22.

  In this embodiment, the case where stepping motors are used as the pan motor 21 and the tilt motor 22 has been described. However, other motors such as a DC motor and a vibration motor (ultrasonic motor) may be used. A position detector such as an encoder may be used for detecting the rotation amount of the motor.

  Next, with reference to FIGS. 2 and 3, the operation of moving the imaging range using the pan head mechanism 20 and the optical image stabilization mechanism (VAP 31) in the surveillance camera system of this embodiment will be described. In the present embodiment, the VAP 31 has a function of reducing image blur due to vibration applied to the camera as described above, and a function of moving the imaging range regardless of the vibration.

  FIG. 2 shows a state where the imaging range is moved by changing the direction of the camera by the pan operation of the pan head mechanism 20. The rectangular double frame indicates the imaging range, and A0 and A1 indicate the positions of the imaging range (first pan stop position) that can be set by the pan operation of the pan head mechanism 20. The moving amount of the imaging range between the two first pan stop positions A0 and A1 is the minimum moving amount of the imaging range corresponding to the rotation amount of one step of the pan motor (stepping motor) 21 that drives the pan head mechanism 20. .

  A person in the figure indicates a subject to be imaged. At the first pan stop positions A0 and A1, the subject is captured at the end of the imaging range. That is, only the pan operation of the pan head mechanism 20 can change the position of the imaging range only at a minimum interval corresponding to the amount of movement of the first pan stop positions A0 and A1, and the subject can be changed at the approximate center of the imaging range. I can't catch it. T0 is a target position to which the imaging range should be moved in order to capture the subject at approximately the center of the imaging range, and is located between the two first pan stop positions A0 and A1.

  In FIG. 3, B <b> 0 to B <b> 8 indicate the positions (second pan stop positions) of the imaging range that can be set by changing the vertex angle of the VAP 31. The moving amount of the imaging range between two adjacent positions among the second pan stop positions B0 to B8 is a moving amount smaller than the minimum moving amount of the imaging range by the pan head mechanism 20. FIG. 3 shows a case where the second pan stop positions B0 to B8 are positions obtained by dividing the first pan stop positions A0 and A1 by 1/8. However, the second pan stop position may be set at a finer interval (for example, an interval finer than the pixel pitch of the image sensor 16), or may be set at a division interval coarser than 1/8.

  For example, the operator operates the external camera control device 70 to instruct the microcomputer 11 to move the imaging range to the target position T0 in order to capture a subject located outside the imaging range at approximately the center of the imaging range. Send. Receiving the movement instruction, the microcomputer 11 first calculates the first pan stop position (one of A0 and A1, which is A0 in this case) that is closest to the target position T0. Then, the microcomputer 11 pans the pan head mechanism 20 to move the imaging range to the first pan stop position A0.

  Subsequently, the microcomputer 11 selects a position (here, the second pan stop position B4) closest to the target position T0 among the second pan stop positions B0 to B8. Then, | B4-A0 |, which is the position difference between the second pan stop position B4 and the first pan stop position A0, and the movement from the first pan stop position A0 to the second pan stop position B4 (target position T0). Calculate the direction. Next, the microcomputer 11 converts the calculated position difference into the change amount of the vertex angle of the VAP 31 and converts the moving direction into the change direction of the vertex angle of the VAP 31. Then, the VAP 31 is operated by the vertex angle change amount in the vertex angle change direction obtained by the conversion. As a result, as shown in FIG. 3, the subject can be captured at substantially the center of the imaging range.

  As described above, according to the present embodiment, even when the position of the imaging range changed (moved) by the pan head mechanism 20 is rough, the position of the imaging range can be changed more finely by the operation of the VAP 31. Therefore, as compared with the conventional imaging system that can only move the imaging range by the pan head mechanism 20, the imaging range can be changed more finely and moved at a lower speed, and imaging is performed while tracking the moving subject. In this case, the imaging range can be moved smoothly.

  In this embodiment, the case where the variable apex angle prism is used as the optical image stabilization mechanism has been described. Instead, the image blur is reduced by shifting the lens or the image sensor in the direction perpendicular to the optical axis. An optical vibration isolation mechanism may be used.

  In this embodiment, the case where the image pickup range is optically moved by the optical image stabilization mechanism has been described. However, the image pickup range is electronically changed in the same manner as in this embodiment by the electronic image stabilization processing described in the second embodiment. It is also possible to move it.

FIG. 4 shows the configuration of a surveillance camera system as an imaging system that is Embodiment 2 of the present invention. The surveillance camera system of the present embodiment slowly combines the pan / tilt operation of the camera by the pan head mechanism 20 and the image clipping operation by the electronic image stabilization processing unit (second imaging range moving means) 13a of the camera. While tracking the moving subject, it is maintained at the approximate center of the imaging range. In FIG. 4, constituent elements common to the first embodiment are denoted by the same reference numerals as in the first embodiment and are not described. In this embodiment, an electronic image stabilization processing unit 13 a is provided in the camera signal processing circuit 13. Further, the VAP described in the first embodiment is not mounted on the lens unit 30 ′.

  FIG. 5 shows an image cut-out operation (electronic image stabilization processing) by the electronic image stabilization processing unit 13a. 5-C in the figure indicates an entire image generated based on the image pickup signal from the image pickup device 16. Reference numerals 5-A and 5-B denote image areas of the same size cut out from the entire image 5-C. The image areas 5-A and 5-B correspond to the imaging range set by the electronic image stabilization processing unit 13a. The electronic image stabilization processing unit 13 a can cut out the image areas 5 -A and 5 -B at timing intervals generated by the timing generator 17.

  The microcomputer 11 integrates the vibration detection signal from the vibration gyroscope 12 to calculate the magnitude and direction of the vibration, and the image obtained by the electronic image stabilization processing unit 13a so as to reduce the image blur according to the calculation result. The region is cut out.

  Control of the position of the imaging range using the pan head mechanism 20 and the electronic image stabilization processing unit 13a in the monitoring camera system of the present embodiment will be described with reference to FIG. Here, the movement instruction from the external camera control device 70 is an instruction to move the imaging range over a range exceeding the minimum movement amount that can be moved by the pan operation of the pan head mechanism 20 (the imaging range is moved following the moving subject). Will be described.

  As described above, the electronic image stabilization processing unit 13 a can cut out the image area at the timing interval generated by the timing generator 17. In the present embodiment, by utilizing this fact, the imaging range is moved by the image region clipping operation of the electronic image stabilization processing unit 13a.

  A0, A1, and A2 shown in the lower part of FIG. 6 indicate positions in the imaging range (first pan stop position) that can be set by the pan operation of the pan head mechanism 20. The amount of movement of the imaging range between adjacent first pan stop positions is the minimum of the imaging range corresponding to the amount of rotation of one step of the pan motor (stepping motor) 21 that drives the pan head mechanism 20 as in the first embodiment. The amount of movement. In this embodiment, A0, A1, and A2 are also used as the positions of moving subjects.

  B0 to B8 indicate the positions of the imaging range (second pan stop position) that can be set by the image region cutting operation by the electronic image stabilization processing unit 13a. The moving amount of the imaging range between two adjacent positions among the second pan stop positions B0 to B8 is a moving amount smaller than the minimum moving amount of the imaging range by the pan head mechanism 20. In the drawing, the second pan stop positions B0 to B8 are positions obtained by dividing 1/8 between adjacent first pan stop positions. However, the second pan stop position may be set at a finer interval (for example, an interval finer than the pixel pitch of the image sensor 16).

  FIG. 6A shows a state in which the subject to be imaged continuously moves in the right direction from the left end of the imaging range set at the first pan stop position A0. If the imaging range is not moved as it is, the subject will eventually go out of the imaging range. For this reason, it is necessary to move the imaging range in the moving direction of the subject.

  However, with the subject moved to the center of the imaging range set at the first pan stop position A0, the pan head mechanism 20 is panned to move the imaging range to the first pan stop position A1 adjacent to the right (fast). As a result, the position of the subject changes to the left end of the imaging range. That is, it is not possible to generate an image with a stable subject position.

  For this reason, in the present embodiment, while the imaging range is set to the first pan stop position A0 by the pan head mechanism 20, the microcomputer 11 does not move while the subject moves in the range from A0 to A1. The mechanism 20 is stopped as it is. That is, the imaging range is not moved by the pan operation of the pan head mechanism 20. Then, the imaging range is sequentially (continuously) moved from B0 to B8, which is the second pan stop position, by the image region cutout operation by the electronic image stabilization processing unit 13a. Accordingly, it is possible to perform follow-up imaging with respect to the subject while maintaining the position within the imaging range of the subject moving in the range from A0 to A1 at substantially the center thereof.

  Further, when the subject moves in the direction A2 beyond A1, the microcomputer 11 moves the pan head mechanism 20 in the direction of movement of the subject (the instruction for movement is given), as shown in FIG. The image pickup range is moved from A0, which is the first pan stop position, to A1. At the same time, the image pickup range (image region cut-out position) is switched (returned) from B8, which is the second pan stop position, to B0 by the image region cut-out operation by the electronic image stabilization processing unit 13a.

  By performing such switching processing for returning the cutout position of the image area, the cutout position reaches the end of the entire image and cannot be moved in the same direction any more, that is, the imaging range is smooth. Prevents being unable to move.

  By matching the speed at which the imaging range is switched by the return switching process with the speed at which the imaging range is moved from A0 to A1 by the pan operation of the pan head mechanism 20, the position of the subject can be substantially equal to the imaging range even during the return switching process. Can be kept central. With the above operation, it is possible to perform follow-up imaging with respect to a good moving subject whose position within the imaging range of the moving subject is stable.

  In each of the above-described embodiments, the movement of the imaging range in the pan direction has been described. However, as shown in FIG. 7, the imaging range can be moved in the tilt direction by a similar operation.

  In each of the above embodiments, the case where the position of the imaging range is controlled by combining the head mechanism and the optical image stabilization mechanism or the electronic image stabilization process has been described. A combination of the first and second imaging range moving means may be used. For example, the motor types of the two pan head mechanisms may be changed (for example, a stepping motor and a DC motor), or the same type of motor (stepping motor) may be used to vary the reduction ratio of the reduction gear. Good.

  Further, in each of the above-described embodiments, the case where the optical image stabilization mechanism and the electronic image stabilization process are also used as means for moving the imaging range has been described, but the image stabilization function is not necessarily required as long as the imaging range can be moved.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

In an imaging system such as a surveillance camera system, the degree of freedom in setting an imaging range can be increased.

DESCRIPTION OF SYMBOLS 10 Camera body 11 Microcomputer 16 Image pick-up element 20 Pan head mechanism 31 Variable apex angle prism

Claims (6)

An imaging device that images a subject within an imaging range and generates an image;
First imaging range moving means for changing the orientation of the imaging device so as to move the imaging range;
Second imaging range moving means capable of moving the imaging range with a movement amount smaller than a minimum movement amount of the imaging range by the first imaging range moving means;
An imaging system comprising: control means for operating the first imaging range moving means and the second imaging range moving means in response to an instruction to move the imaging range. When the movement instruction is an instruction to move the imaging range to a target position between two positions that can be moved by the minimum movement amount by the operation of the first imaging range moving means. The first imaging range moving means is operated to move the imaging range to one of the two positions, and the second imaging range moving means is operated to move to the target position. The imaging system according to claim 1. The control means moves the first imaging range when the movement instruction is an instruction to move the imaging range over a range exceeding the minimum movement amount that can be moved by the operation of the first imaging range moving means. And moving the imaging range in the direction in which the movement instruction is given, and operating the second imaging range moving unit so that the position of the subject in the imaging range is maintained. The imaging system according to claim 1. 4. The apparatus according to claim 1, wherein both the first imaging range moving unit and the second imaging range moving unit change an orientation of the imaging apparatus by driving an actuator. 5. Imaging system. The first imaging range moving means drives an actuator to change the orientation of the imaging device,
The said 2nd imaging range moving means moves the said imaging range optically or electronically, without changing the direction of the said imaging device, The Claim 1 characterized by the above-mentioned. Imaging system. The imaging system according to claim 5, wherein the second imaging range moving unit is also used as an image stabilization unit for reducing image blur due to vibration of the imaging apparatus.