JP2008199389A - Monitoring camera and monitoring camera control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monitoring camera and monitoring camera control method capable of smoothly tracking a subject even when the subject passes through around just under an imaging means. <P>SOLUTION: A just under traverse line Lc is previously set in a camera 12 by noticing that an advancing direction of a person who passes through just under the camera 12 can be limited to a direction of striding over a certain line perpendicularly many times. When a person being currently tracked approaches the just under traverse line Lc, the direction of the camera is set to a position of a linear symmetry with respect to the just under traverse line Lc where the person may advance, and the person who passes through just under the camera is caught to start tracking. Consequently, it is possible to smoothly perform automatic tracking around just under the camera. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surveillance camera that automatically tracks a subject and a surveillance camera control method.

  Conventionally, surveillance cameras have a camera with a turntable that changes the imaging direction of the camera body to the pan and tilt directions, and controls the camera in the pan and tilt directions and controls the zoom function of the camera to control the subject. There is one that automatically tracks (see, for example, Patent Document 1).

JP 2002-27442 A

  However, in the conventional surveillance camera described above, when the subject passes under the camera, if the subject is a person, only the head and shoulders are captured, and the panning control causes the screen to rotate. Since it moves, there is a problem that pan control is difficult and tracking cannot be performed smoothly. Incidentally, since it is assumed that the person is a vertically long object, if only the head and shoulders are captured, it is naturally difficult to identify the person.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a surveillance camera and a surveillance camera control method capable of smoothly tracking even when a subject passes near the vicinity of an imaging unit.

  The surveillance camera according to the present invention includes an imaging unit that images a subject, a turntable that moves the imaging unit in the pan and tilt directions, and a tracking target subject for identifying an image captured by the imaging unit. Video processing means for generating pan and tilt information for tracking the subject by performing video processing, and tracking the subject by controlling the turntable according to the pan and tilt information generated by the video processing means When the subject approaches close to the vicinity of the imaging means, the tracking of the subject is temporarily stopped to predict the moving direction of the subject, and the turntable is controlled with respect to the predicted moving direction. Tracking means for changing the direction of the imaging means and resuming tracking after the subject has passed near the imaging means.

  According to the above configuration, when the subject approaches the vicinity immediately below the imaging unit, the subsequent movement direction of the subject is predicted, and the direction of the imaging unit is changed with respect to that direction. Tracking can be resumed smoothly after passing the vicinity.

  In the surveillance camera of the present invention, the tracking unit controls the rotating base at a line-symmetrical position with respect to an index indicating a position directly below the imaging unit when the subject approaches the vicinity of the imaging unit. By doing so, the orientation of the imaging means is changed. This is because the traveling direction of a person who passes right under the imaging means can usually be limited to a direction that straddles a certain line in many cases.

  According to the above-described configuration, a line that traverses directly below the imaging means (referred to as a “directly transverse line” in the embodiments described later) is set in advance, and the subject being tracked approaches the transverse line that is directly below. In this case, by directing the imaging means to a position that is line-symmetric with respect to the straight line that will go forward, and waiting for the subject, automatic tracking near the imaging means can be performed smoothly.

  In the surveillance camera of the present invention, the tracking unit analyzes a change in position due to panning and tilting of the imaging unit, and when the subject passes near the imaging unit, the subsequent moving direction of the subject And the orientation of the imaging means is changed by controlling the turntable with respect to the predicted moving direction.

  According to the above configuration, the position change due to panning and tilting of the imaging unit is analyzed, and when the subject passes near the imaging unit, the subsequent moving direction is predicted, and the direction of the imaging unit with respect to the direction is predicted. Therefore, automatic tracking near the imaging means can be performed smoothly.

  Also, the surveillance camera control method of the present invention performs panning and tilt information for tracking the subject by performing video processing for specifying the subject to be tracked on the video imaged by the imaging means for imaging the subject. A video processing step for generating the image, a tracking step for tracking the subject by controlling the turntable according to the pan and tilt information generated in the video processing step, and a case where the subject is close to the vicinity of the imaging unit. The tracking of the subject is temporarily stopped to predict the moving direction of the subject thereafter, and the direction of the imaging unit is changed with respect to the predicted moving direction of the subject, so that the subject is directly below the imaging unit. A tracking resumption process for resuming tracking after passing the vicinity.

  According to the above method, when the subject approaches close to the vicinity of the imaging unit, the subsequent movement direction of the subject is predicted, and the direction of the imaging unit is changed with respect to that direction. Tracking can be resumed smoothly after passing the vicinity.

  According to the surveillance camera and surveillance camera control method of the present invention, it is possible to track smoothly even when the subject passes near the vicinity of the imaging means.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a surveillance camera according to Embodiment 1 of the present invention. In the figure, a surveillance camera 1 according to the present embodiment includes a camera microcomputer 10 that controls each part of the surveillance camera 1 and a flash ROM (Read Only memory) that stores a program for controlling the camera microcomputer 10. Non-volatile memory 11, camera 12 that is an imaging means for imaging a subject, turntable 13 for directing camera 12 in the pan and tilt directions, and pan origin sensor for detecting the origin of camera 12 in the pan direction 14, a tilt origin sensor 15 for detecting the origin of the camera 12 in the tilt direction, rotation results according to the detection results of the pan origin sensor 14 and the tilt origin sensor 15, and a PT (PAN, TILT) control instruction from the camera microcomputer 10. Based on the video signal from the servo microcomputer / motor driver 16 that controls the table 13 and the camera 12, motion detection and frame A person who is the subject is identified by performing processing such as inter-frame difference, and a PTZ control instruction for tracking is generated based on the identified person and PTZ (PAN, TILT, ZOOM) position information given from the camera microcomputer 10 And an image processing / automatic tracking process DSP (Digital Signal Processor) 17 provided to the camera microcomputer 10.

  The camera 12 includes a zoom lens unit 121, an image sensor 122 such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) that converts an image obtained via the zoom lens unit 121 into an electrical signal, An AGC (Automatic Gain Control) and A / D unit 123 that performs digital conversion by performing control to keep the signal level constant is provided.

  The camera microcomputer 10 controls the pan motor 131 and the tilt motor 132 of the turntable 13 by giving a PT control instruction regarding pan and tilt to the servo microcomputer / motor driver 16 in accordance with the PTZ control instruction input from the video processing / automatic tracking process DSP 17. Then, a Z control instruction regarding zoom is given to the camera 12 to control the zoom lens unit 121. The camera microcomputer 10 controls the servo microcomputer / motor driver 16 when the power is turned on and also controls the zoom lens unit 121 of the camera 12 to detect the origin position. The camera microcomputer 10 always grasps the position information of the camera 12.

  In addition, the camera microcomputer 10 always receives PTZ position information from the pan / tilt position information of the camera 12 input from the servo microcomputer / motor driver 16 and the zoom information input from the zoom lens unit 121 of the camera 12 during operation. And is input to the video processing / automatic tracking processing DSP 17, and the servo microcomputer / motor driver 16 and the zoom lens unit 121 of the camera 12 are controlled in accordance with the PTZ control instruction input from the video processing / automatic tracking processing DSP 17. To track a person.

  When the person approaches near the camera, the camera microcomputer 10 temporarily stops tracking the person, and the camera 12 is referred to as a pre-set index (in this embodiment, a “directly crossing line”). ) And wait for the person to appear again in a line-symmetric position. This is because attention is usually paid to the fact that the direction of movement of a person passing directly below the camera 12 can often be limited to a direction that vertically crosses a certain line (a straight line below). A line is set, and when the person being tracked approaches this right-down crossing line, the camera 12 is pointed at a line-symmetrical position with respect to the right-down crossing line that will be advanced.

  FIG. 2A is a diagram in which the state when the person 20 as the subject approaches the vicinity just below the camera is viewed obliquely from above, and FIG. 2B is a diagram in which the same child is viewed from directly above. In addition, A and B in the figure are angle of view that is line-symmetric with respect to a transverse line Lc that is set directly below the camera 12. In this case, the angles of view A and B are, for example, 20 degrees. When the person 20 is captured at the angle of view A, tracking is temporarily stopped, and the pan angle is determined so that the angle of view B is symmetrical with the angle of view A, and the position of the camera 12 is changed. Then, tracking is resumed from this predicted position.

  As described above, according to the surveillance camera 1 according to the present embodiment, it is noted that the traveling direction of the person passing directly below the camera 12 can often be limited to a direction straddling a certain line vertically. Lc is set in the camera 12 in advance, and when the person being tracked approaches the straight crossing line Lc, the direction of the camera 12 is set to a position symmetrical with respect to the straight crossing line Lc that will be followed. Since the tracking is resumed by setting and capturing the person 20 that has passed directly under the camera, automatic tracking near the camera can be performed smoothly.

(Embodiment 2)
In the above-described first embodiment, the right-down crossing line Lc is set in the camera 12 in advance, and when the person being tracked approaches the right-down crossing line Lc, the right-down crossing line Lc that the person will move forward is the next. The direction of the camera 12 is set at a line-symmetrical position with respect to the tracking camera 1A according to the present embodiment. The movement prediction is performed after the person who is the target subject passes near the camera. Since the configuration of the apparatus is the same as that of FIG. 1, FIG. 1 is used. However, there is a difference in that the memory 11 stores a calculation program for the camera microcomputer 10 to perform a movement prediction after the person passes near the camera. The movement prediction method after passing near the camera will be described below.

  FIG. 3 is a view of the camera 12 and the person 20 as the subject viewed from the lateral direction, and FIG. 4 is a view of the camera 12 and the subject 20 as viewed from directly above. 3 and 4, 30 is a range (circle) designated to be directly under the camera, P0 is a position directly below the camera, P1 is a tracking start position of the person, P2 is a position where the person is in the vicinity of the camera, and P3 is The predicted position after moving the person is shown. In addition, h indicates the installation height of the camera 12 from the ground, and is set in the camera 12 in advance when the camera 12 is installed.

(1) First, the distance a at the start of tracking, that is, the distance from the position P0 directly below the camera to the tracking start position P1 of the person is obtained. As shown in FIG. 5, the distance a at the start of tracking can be determined by dividing the installation height h of the camera 12 in tan _1. That can be determined by the formula a = h / tanγ _1.

(2) Next, the radius b of the circle 30 designated as just below the camera is obtained. As shown in FIG. 6, the radius b of the circle 30 can be determined by dividing the height h of the camera 12 at tan _2. That can be obtained by the formula b = h / tanγ _2.

(3) Next, an angle α formed between the person's tracking start position P1 and the position P2 at which the person approaches the vicinity of the camera is obtained. This angle α can be obtained by subtracting the pan angle γ ₄ when the person is approaching just below the camera from the pan angle γ ₃ at the start of tracking. That is, it can be obtained by the equation: α = pan angle γ ₃ −pan angle γ ₄ .

(4) Next, the distance c between the tracking start position P1 of the person and the position P2 at which the person is approaching just below the camera is obtained. This distance c can be obtained by using the cosine theorem. That ^can be obtained by the formula ^{c 2 = a 2 + b 2} -2abcosα.

(5) Next, an angle β formed between the position P0 directly below the camera and the position P2 at which the person approaches the camera is determined. This angle β can also be obtained by using the cosine theorem. That is, it can be obtained by the equation of cos β = (a ² + c ² −b ² ) / 2ac.

  (6) Next, an angle θ which is a half of an angle formed between the position P2 where the person approaches the vicinity of the camera and the predicted position P3 after moving the person is obtained. This angle θ can be obtained by using the angles α and β obtained in the previous step. That is, it can be obtained by the equation θ = 180 ° −90 ° −β−α.

Therefore, the predicted position P3 after the movement of the person is a position obtained by further rotating the pan angle by 2θ from the position P2 at which the person approaches the vicinity of the camera. In this case, since the tilt angle is defined gamma _2, may only pan angle seek. In this way, the pan angle of the predicted position P3 after the person is moved is obtained. The angle at which the camera pan 12 is 2θ moved relative gamma _4, tilt controlling the direction of the camera 12 so that the gamma _2.

  The person 20 as the subject moves substantially linearly, but the movement direction often changes little by little until reaching a position just below the camera. (6) may be repeated every short time. In this way, it is possible to obtain an accurate predicted position after moving the person immediately before the position approaching just below the camera.

As described above, according to the monitoring camera 1A according to the present embodiment, the distance a from the position P0 directly below the camera 12 to the tracking start position P1 of the person 20 that is the subject to be tracked and the position directly below the camera 12 are designated. The angle b between the radius b of the circle 30 and the tracking start position P1 of the person centered on the position P0 directly below the camera 12 and the position P2 where the person approaches the camera directly below (that is, panning at the start of tracking) based difference) and the pan angle gamma ₄ when the angle gamma ₃ and human is approaching the vicinity of directly below the camera performs movement prediction after passing near the camera beneath the person 20, and set the camera position to the predicted position Since it is corrected, automatic tracking near the camera can be performed smoothly.

  INDUSTRIAL APPLICABILITY The present invention has an effect that, even when a subject passes near the imaging unit, it can be smoothly tracked without being confused, and can be applied to a surveillance camera system that automatically tracks a subject. .

1 is a block diagram showing a schematic configuration of a surveillance camera according to Embodiment 1 of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the surveillance camera control method in the surveillance camera which concerns on Embodiment 1 of this invention, (a) is the figure which looked at the mode when the person who is a subject approached the camera direct vicinity from diagonally upward. (B) is a view of the same child as seen from directly above. It is a figure for demonstrating the surveillance camera control method in the surveillance camera which concerns on Embodiment 2 of this invention, and the figure which looked at the camera and the person who is a subject from the horizontal direction It is a figure for demonstrating the surveillance camera control method in the surveillance camera which concerns on Embodiment 2 of this invention, and the figure which looked at the camera and the person who is a subject from right above The figure for demonstrating how to obtain | require the distance a at the time of the tracking start in FIG. 3 or FIG. The figure for demonstrating how to obtain | require the radius b of the circle | round | yen designated as right under the camera in FIG. 3 or FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Surveillance camera 10 Camera microcomputer 11 Memory 12 Camera 13 Turntable 14 Pan origin sensor 15 Tilt origin sensor 16 Servo microcomputer / motor driver 17 Video processing / automatic tracking processing DSP
20 People 30 Range that is specified as just under the camera (circle)
Lc Crossing line just below P0 Position just below the camera P1 Tracking start position of the person P2 Position where the person is approaching directly below the camera P3 Predicted position after moving the person

Claims (4)

Imaging means for imaging a subject;
A turntable for moving the imaging means in the pan and tilt directions;
Video processing means for performing video processing for specifying a subject to be tracked on the video imaged by the imaging means to generate pan and tilt information for tracking the subject; and
The panorama is controlled according to the pan and tilt information generated by the video processing means to track the subject, and the subject tracking is temporarily stopped when the subject approaches the vicinity of the imaging means. Then, after the moving direction of the subject is predicted, the direction of the imaging unit is changed by controlling the turntable with respect to the predicted moving direction, and the subject passes near the vicinity of the imaging unit. Tracking means for resuming tracking;
Surveillance camera with.   The tracking means controls the orientation of the imaging means by controlling the rotating base at a line-symmetrical position with respect to an index indicating a position directly below the imaging means when the subject approaches near the vicinity of the imaging means. The surveillance camera according to claim 1 to be changed.   The tracking unit analyzes a change in position due to panning and tilting of the imaging unit, predicts a moving direction of the subject when the subject passes near the imaging unit, and sets the predicted moving direction to the predicted moving direction. The surveillance camera according to claim 1, wherein the orientation of the imaging unit is changed by controlling the turntable. A video processing step for generating pan and tilt information for tracking the subject by performing video processing for specifying the subject to be tracked on the video imaged by the imaging means for imaging the subject;
A tracking step of tracking the subject by controlling the turntable according to the pan and tilt information generated in the video processing step;
When the subject approaches close to the vicinity of the imaging unit, the tracking of the subject is temporarily stopped to predict the subsequent movement direction of the subject, and the imaging unit's movement direction is predicted with respect to the predicted movement direction of the subject. A tracking resumption step of resuming tracking after changing the direction and the subject passes near the vicinity of the imaging means;
A surveillance camera control method comprising:

Images