KR20220029034A - CCTV System Capable of Tracing Interesting Target by Sound Detection and Surveillance Method thereof - Google Patents

Abstract

The present invention relates to a CCTV system for crime prevention and a monitoring method thereof. The CCTV system for crime prevention of the present invention can detect a direction of noise source of noise generated in a monitoring space using a microphone disposed in a 3D space. The camera can be rotated in the detected direction to take pictures. In this process, a dead zone may be set and managed in order to prevent the direction of the noise source from being incorrectly calculated by the reflected and sensed noise. If the direction calculated from the noise belongs to the dead zone, the system of the present invention ignores the calculated direction and does not process the same, so that true noise source can be identified.

Description

CCTV System Capable of Tracing Interesting Target by Sound Detection and Surveillance Method thereof

The present invention calculates the direction of a noise source generated in a monitoring space using a plurality of microphones disposed in the space, and rotates the camera in the calculated direction of the noise source to obtain a noise-related image. It's about monitoring.

In a system that recognizes and tracks a specific object by arranging a PTZ (Pan Tilt Zoom) camera, the main methods of object recognition are image processing and object recognition and voice recognition. .

Among them, the method of recognizing an object by voice recognition is to place a plurality of microphones in a three-dimensional space to three-dimensionally recognize the direction of sound in space, and to pan or tilt the camera in that direction. ) method has been mainly used.

However, even with the voice recognition method, when the direction is calculated based on the noise reflected by the surrounding structure rather than the noise directly sensed from the noise source, a direction completely different from the real noise source is tracked.

This situation may make it unnecessary to operate the camera according to the sound source detection by preventing other dangerous situations from being monitored.

Republic of Korea Patent Publication No. 10-2010-0121086

An object of the present invention is to calculate the direction of a noise source generated in a monitoring space using a plurality of microphones arranged in a space, and rotate the camera in the calculated direction of the noise source to obtain a noise-related image. To provide a CCTV system and a monitoring method therefor.

Another object of the present invention is to provide a crime prevention CCTV system capable of eliminating errors in the direction of a noise source by noise that is not transmitted directly from the noise source but is reflected and sensed by surrounding structures, and a monitoring method therefor.

A CCTV system for crime prevention according to the present invention for achieving the above object includes a pan-tilt zoom camera that generates an image by taking pictures of the surroundings, four microphones arranged at intervals of 90° along the circumference of a virtual circle parallel to the ground, and and a microphone unit configured to detect noise from a surrounding noise source by having at least one microphone disposed on a vertical line passing through the center point of the circle, and a sound source detection unit configured to calculate a direction of the noise source using the microphone unit.

In addition, the CCTV system includes a camera angle control unit, a camera zoom control unit, and a dead zone processing unit. The camera angle control unit calculates panning and tilting angles for the pan/tilt zoom camera so that the pan/tilt zoom camera faces the noise source based on the direction of the noise source calculated by the sound source detection unit, By rotating the pan/tilt zoom camera at the calculated panning and tilting angles, it is possible to control the area where the noise is generated to be photographed. The camera zoom control unit may control the zoom of the pan/tilt zoom camera by calculating a zoom-control value of the pan/tilt zoom camera according to the tilt angle calculated by the camera angle control unit.

The dead zone processing unit, when the calculated direction of the noise source belongs to a preset dead zone, determines that the calculated noise source is not a real noise source, and sets the calculated direction of the noise source to the camera angle control unit and the camera zoom control unit. Ignoring the detected noise by not providing it to Here, the dead zone may be set as an area having a fixed structure, but belonging to a monitoring area of the pan/tilt zoom camera and set from an area having a preset height or higher.

Furthermore, the dead zone processing unit, even when the calculated direction of the noise source belongs to a preset dead zone, if other noise sources are not continuously calculated within a time within a preset range, the dead zone belongs to The direction of the noise source may be provided to the camera angle control unit and the camera zoom control unit to control the pan/tilt zoom camera to rotate in the direction of the noise source to take pictures.

According to another embodiment of the present invention, when the sound source detection unit calculates the distance to the noise source by using the microphone unit, the dead zone processing unit distance information from the sound source detection unit to the noise source together with direction information of the noise source may be provided, and after calculating the height of the noise source on the ground, if the calculated height on the ground is greater than or equal to a preset reference height (Y), it may be determined that the noise source belongs to a dead zone.

The monitoring method of the CCTV system for crime prevention according to another embodiment of the present invention is arranged vertically on a vertical line passing through the center point of the four microphones and the center point of the circle and four microphones arranged at intervals of 90 ° along the circumference of a virtual circle parallel to the ground. A first step of detecting the noise of the surrounding noise source by a microphone unit having two microphones; a second step of calculating, by a sound source detection unit, a direction of the noise source using the noise detected by the microphone unit; A camera angle control unit calculates panning and tilting angles for the pan/tilt zoom camera so that the pan/tilt zoom camera faces the noise source based on the direction of the noise source calculated by the sound source detection unit, a third step of rotating the pan/tilt zoom camera by the calculated panning and tilting angles to control to photograph an area in which the noise is generated; a fourth step of controlling the zoom of the pan/tilt zoom camera by a camera zoom control unit calculating a zoom-control value of the pan/tilt zoom camera according to the tilt angle calculated by the camera angle control unit; and the dead zone processing unit determines whether the direction of the noise source calculated by the sound source detection unit is due to the reflected noise rather than the real noise source, and if it is determined that the direction is due to the reflected noise, the third and fourth steps are not performed. and ignoring the sensed noise.

The CCTV system for crime prevention of the present invention can basically take an image in the monitoring space and provide it to the control center. Furthermore, noise generated in the monitoring space is detected using a plurality of microphones placed near the camera, the direction of the noise source is detected from the noise, and then the camera is rotated in the detected direction to obtain an image related to the noise can do.

In this process, the system of the present invention can set and manage a dead zone in order to prevent the direction of the noise source from being incorrectly calculated by the reflected and sensed noise. If the direction calculated from the noise belongs to the dead zone, the system of the present invention ignores and does not process the calculated direction, thereby identifying the true source of the noise.

However, even if the calculated direction belongs to the dead zone, if other noise sources are not continuously calculated within the time within the preset range, the direction of the noise source belonging to the dead zone is not ignored and the image is processed by the camera. By controlling the photographing, it is possible to prevent a situation in which the noise is not reflected but is determined to be reflected noise, thereby responding to an unexpected situation.

1 is a block diagram of a CCTV system for crime prevention through sound source detection according to an embodiment of the present invention.
2 is a perspective view showing a camera, a microphone unit, and a sound source detection unit included in the CCTV system of the present invention.
3 is a perspective view illustrating in more detail a microphone unit and a sound source detection unit according to an embodiment of the present invention;
Figure 4 is a conceptual diagram provided for the description of the dead zone of the present invention.
5 is a flowchart provided for explaining the operation of the CCTV system according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 and 2, the crime prevention CCTV system 100 of the present invention can basically capture and store a monitoring area, and can more precisely capture the on-site situation when an unexpected situation occurs in the monitoring space. . The surveillance area is a place subject to crime prevention monitoring such as inside/outside a park or a building, and in particular, in the description of the present invention, the monitoring area may be limited to an area captured by the CCTV system 100 .

The CCTV system 100 includes a Pan-Tilt-Zoom (PTZ) camera 110 , a microphone unit 130 , a sound source detection unit 150 , and a control device 170 .

Referring to FIG. 2 , the pan/tilt zoom camera 110 , the microphone unit 130 , and the sound source detection unit 150 are a structure installed on one side of the monitoring space, a normal post ( 支柱 ) 10 , in particular, the It is installed on the horizontal support 11 installed at the top. The sound source detection unit 150 and the control device 170 are connected through the network 20 . Here, the network 20 may correspond to an IP (Internet Protocol) network capable of packet data communication, a mobile communication network, or the like. By using the network 20, the control device 170 can be placed in a control center at another location away from the monitoring space. On the other hand, when the control device 170 is installed on the post 10 , the sound source detection unit 150 may be a component of the control device 170 instead of being implemented as a separate device as described below.

The pan/tilt zoom camera 110 includes a camera 111 capable of variable zoom by controlling a lens, and a pan/tilt controller 113 for controlling pan/tilt of the camera 111 . The pan/tilt zoom camera 110 operates in a normal mode and an event mode. In the normal mode, a preset position is photographed with a preset zoom value, and in the event mode, the focal length and direction of the camera are adjusted according to the PTZ parameter provided by the control device 170 to shoot. The captured image is provided to the control center or the control device 170 . Here, the PTZ parameter includes a pan-tilt-control value for controlling the pan-tilt controller and a zoom-control value for controlling the zoom.

The pan/tilt zoom camera 110 may convert a captured image into a digital signal and provide it to a control center or the like, and may be an IP camera having a wired or wireless IP interface for connection to the network 20 .

It is sufficient if the microphone unit 130 is provided on one side of the pan/tilt zoom camera 110 , and is preferably installed side by side with the pan/tilt zoom camera 110 on the horizontal support 11 at the top of the post 10 . The microphone unit 130 includes a plurality of microphones to convert noise generated in the monitoring space into an audio signal and provide it to the sound source detection unit 150 . The sound source detection unit 150 may calculate direction information of a noise source generating noise in a space by using the audio signal provided by the microphone unit 130 .

For example, (a) of FIG. 3 is a diagram for schematically explaining the arrangement of six microphones of the microphone unit 130, and (b) is a perspective view of the microphone unit 130 according to an embodiment of the present invention. am.

Referring to Figure 3 (a), first, the microphone unit 130 is provided with four microphones (131, 133, 135, 137) arranged at intervals of 90 ° along the circumference of the virtual circle 30 on the virtual plane. to detect the noise of the surrounding noise source. Here, the virtual circle 30 is preferably substantially parallel to the ground.

Even if the four microphones 131 , 133 , 135 , 137 of the microphone unit 130 detect noise from the same noise source, the four microphones 131 , 133 , 135 , and 137 are the corresponding noise sources due to the difference in their arrangement positions. An error occurs at the time of detection. That is, a phase difference occurs between the audio signals provided by the four microphones 131 , 133 , 135 , and 137 to the sound source detection unit 150 . The sound source detection unit 150 may detect the direction of the noise source at least on the corresponding virtual plane by a geometric calculation method based on the phase difference. Furthermore, it is possible to measure the plane distance from the virtual plane to the noise source.

Furthermore, the microphone unit 130 of the present invention may further include at least one microphone on a vertical line passing through the center point of the virtual circle 30 . In FIG. 3, two microphones 139 and 141 are further provided on a vertical line passing through the center point of the virtual circle 30 to provide a total of six microphones 131, 133, 135, 137, 139, 141 from the same noise source. An example of detecting transmitted noise is shown. In this case, as described above, when the audio signals provided by the six microphones 131 , 133 , 135 , 137 , 139 , and 141 are higher than a preset level, the sound source detecting unit 150 detects a phase difference between the six audio signals. can be used to calculate the direction and distance of the noise source in 3D space. The direction and distance calculation of the sound source detection unit 150 may be performed by various conventionally known methods, and the method disclosed in Korean Patent Laid-Open No. 10-2010-0121086 is an example.

The sound source detection unit 150 provides the calculated direction information of the noise source in the three-dimensional space to the control device 170 . In this case, when the control device 170 is disposed in an external control center, the sound source detection unit 150 may include a network interface for connecting to the network 20 .

Referring to FIG. 3B , the microphone unit 130 and the sound source detection unit 150 of the present invention may be assembled as one component.

Six microphones 131 , 133 , 135 , 137 , 139 , 141 are disposed below the sound source detection unit 150 , and a cover 143 for blocking noise from the upper side is provided on the upper portion of the sound source detection unit 150 . is provided. The cover 143 also blocks other snow and rain.

As described above, the control device 170 may be disposed on one side of the post 10 by embedding the sound source detection unit 150 , or may be disposed in the control center through the network 20 as shown in FIG. 1 . When connected through the network 20, the control device 170 may be connected to a plurality of sound source detection units, and may control a plurality of pan/tilt zoom cameras 110 disposed in a plurality of monitoring spaces.

The control device 170 may control the pan/tilt zoom camera 110 to photograph the noise source centered on the noise source by using the direction of the noise source provided by the sound source detection unit 150 . Through this, an unexpected situation that caused noise in the monitoring space can be recorded as an image. Additionally, the control device 170 may receive and process an image (video) provided by the pan/tilt zoom camera 110 .

For this operation, the control device 170 includes a camera angle control unit 171 , a camera zoom control unit 173 , and a dead zone processing unit 175 .

The camera angle control unit 171 is based on the direction of the noise source calculated and provided by the sound source detection unit 150, so that the optical axis of the pan/tilt zoom camera 110 faces the noise source, among the PTZ parameters for the pan/tilt zoom camera 110 . Calculate the panning angle and tilting angle. The camera angle control unit 171 calculates a pan/tilt-control value according to the calculated panning and tilting angles and provides them to the pan/tilt controller 113 of the pan/tilt zoom camera 110, so that the pan/tilt zoom camera 110 is used. Control the noise source to be photographed. The panning angle and tilting angle calculation of the camera angle control unit 171 may be controlled by a conventionally known method based on the direction provided by the sound source detection unit 150 .

The camera zoom control unit 173 calculates a zoom-control value for zoom control of the pan/tilt zoom camera 110 according to the direction of the noise source calculated by the sound source detection unit 150 and provides it to the pan/tilt zoom camera 110 . Accordingly, the camera 111 of the pan/tilt zoom camera 110 automatically adjusts the focal length according to the zoom-control value to generate an enlarged image. The zoom-control value calculation of the camera zoom control unit 173 may be obtained by a geometric method using the direction of the noise source calculated by the sound source detection unit 150 or the tilting angle calculated by the camera angle control unit 171 .

For example, when it is assumed that the height of the noise source is constant like the average height of a person, a tilting angle can be used. Since the height of the pan/tilt zoom camera 110 is fixed, the tilt angle corresponds to the straight line distance to the noise source of a certain height by geometrical logic. Accordingly, if the zoom-control value according to one tilting angle is arbitrarily set, the zoom-control value can be set proportionally to the other tilting angles as well.

By calculating the zoom-control value of the pan-tilt zoom camera 110 and providing it to the pan-tilt zoom camera 110 , the pan-tilt zoom camera 110 controls the zoom-control value to enlarge or reduce the image. According to an embodiment, instead of the direction of the noise source, the zoom-control value may be calculated using the tilt angle calculated by the sound source detection unit 150 .

The dead zone processing unit 175 checks whether the direction of the noise source calculated and provided by the sound source detection unit 150 is included in a preset dead zone, and if included in the dead zone, ignores the direction information of the noise source. The camera angle control unit 171 and the camera zoom control unit 173 are controlled.

Even if there is only one noise source, the number of noises actually acquired by the microphone unit 130 due to reflection of noise by various structures, buildings, etc. existing in the monitoring space may be plural with a time difference. Since the direction of the noise source calculated by the reflected noise is incorrect information, the panning angle and the tilting angle should not be calculated based on this information.

In order to block the effect of such reflected noise, the dead zone processing unit 175 sets a dead zone, and when the direction of the noise source calculated and provided by the sound source detection unit 150 is included in the dead zone, the direction information of the noise source is provided. control to ignore.

The dead zone is set as an area with a fixed structure among areas with a preset height or higher belonging to the monitoring area of the pan/tilt zoom camera 110 . Here, the preset height may be determined in consideration of a person's height, which is a major noise source in the monitoring space, and may be set to, for example, approximately 2 meters.

Figure 4 (a) is a side view of the monitoring space, (b) is a plan view of the monitoring space, an example of setting the area in which the structure (B) is arranged among the areas above the preset height (Y) as the dead zone (D). . 4 shows four noise source direction vectors (x1 to x4). This direction vector is determined by an angle in a plane perpendicular to the ground as in (a) of FIG. 4 and an azimuth in a plane parallel to the ground as in (b). Among the four direction vectors x1 to x4, only x1 belongs to the dead zone D.

A noise source (eg, a person) that the CCTV system 100 of the present invention considers as a monitoring target cannot exist where the x1 direction vector passes.

The control center monitors images provided from a plurality of CCTV systems 100 to monitor a surveillance area captured by each camera device.

Hereinafter, with reference to FIG. 5, the operation of the CCTV system 100 for crime prevention of the present invention will be described.

<Normal mode status: S501, S503>

In the normal mode, the pan/tilt zoom camera 110 captures a surveillance space with a preset zoom value while looking at a preset direction (S501). The microphone unit 130 detects noise generated in the monitoring space and provides it to the sound source detection unit 150, and the sound source detection unit 150 continues to monitor whether noise above a certain level is detected (S503).

<Event occurrence according to noise detection: S505 to S515>

When the sound source detection unit 150 detects a noise above a certain level, the direction of the noise source of the noise is determined using the audio signals provided by the six microphones 131 , 133 , 135 , 137 , 139 and 141 of the microphone unit 130 . Calculate (S505).

The sound source detection unit 150 provides the calculated direction information of the noise source to the control device 170 (S507).

<Determining whether it belongs to the dead zone: S509>

When the direction information of the noise source is transmitted from the sound source detection unit 150, the dead zone processing unit 175 first determines whether the direction of the noise source belongs to the dead zone. If it belongs to the dead zone, the sound source detection unit 150 ignores the corresponding event and does not perform any further processing. If the direction of the noise source does not belong to the dead zone, the dead zone processing unit 175 provides direction information of the noise source to the camera angle control unit 171 and the camera zoom control unit 173 (S509).

The dead zone processing unit 175 ignores the direction of the noise source belonging to the dead zone, even if the direction of the noise source belongs to the dead zone, if other noise sources are not continuously calculated within a predetermined range of time (around several seconds) By providing the direction information of the noise source to the camera angle control unit 171 and the camera zoom control unit 173 without doing so, it is possible to respond to an unexpected situation.

<If not in the dead zone: S511, S513>

When the camera angle control unit 171 and the camera zoom control unit 173 receive direction information of the noise source from the dead zone processing unit 175, they calculate a panning angle, a tilting angle, and a zoom value (S511). Subsequently, the camera angle control unit 171 provides the pan/tilt control value based on the calculated panning angle and the tilt angle to the pan/tilt control unit 113 , and the camera zoom control unit 173 controls the zoom based on the calculated zoom value. The value is provided to the camera 111 (S513, S515).

<Shooting by event mode: S517, S519>

The pan/tilt controller 113 of the pan/tilt zoom camera 110 rotates the camera 111 according to the pan/tilt-control value, and the camera 111 controls the zoom according to the zoom-control value to shoot focusing on the noise source. do.

The pan/tilt zoom camera 110 provides the captured image to the control center. When the control device 170 includes a separate image processing unit or an image storage medium, an image may be provided to the control device 170 .

The CCTV system 100 of the present invention described above goes beyond simply providing an image of the entire monitoring space like the conventional closed circuit system, and tracks the location of the noise source of the noise generated in the monitoring space to detect the noise source. It is possible to provide a more detailed and favorable image for observation. Accordingly, when noise of a certain level or higher is generated in a space, an image related to the noise can be provided to the control center, and when such noise is detected, a separate alarm message can be directly transmitted to the control center.

<Example; Cancel event mode>

The dead zone processing unit 175 performs image processing on the image provided after the pan/tilt zoom camera 110 rotates according to the pan-tilt-control value provided from the camera angle control unit 171 and moves to the center of the image. Determines whether an object exists.

If there is no moving object in the center of the image, it is determined that the event is not caused by a true noise source, and the event mode is canceled. Accordingly, the pan/tilt zoom camera 110 may return to the basic mode state of step S501.

In addition, the event mode is (1) when the preset time has expired after starting the event mode, (2) when an event caused by another noise source occurs, (3) when there is an administrator's control through the control device 170, etc. can be released

<Another embodiment>

According to an embodiment, the dead zone processing unit 175 may perform the same operation without determining a preset dead zone. To this end, the dead zone processing unit 175 must be provided with distance information from the sound source detection unit 150 to the noise source along with direction information of the noise source.

The dead zone processing unit 175 calculates the height of the noise source on the ground by using the distance information to the noise source along with the direction information of the noise source. First, (1) calculating the angle (for example, tilting angle) of the noise source in a plane perpendicular to the ground from the direction information of the noise source, and then (2) using the angle and distance information to the noise source, the height of the noise source on the ground can be calculated.

If the height of the calculated noise source on the ground is greater than or equal to the preset reference height (Y), it is determined that it belongs to the dead zone, and the dead zone processing unit 175 ignores the direction information of the noise source, and the pan/tilt zoom camera ( 110) control is not performed.

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and it is common in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications may be made by those having the knowledge of, of course, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

Claims (4)

In the crime prevention CCTV system,
A pan/tilt zoom camera that creates an image by photographing the surroundings;
a microphone unit comprising four microphones disposed at intervals of 90° along the circumference of a virtual circle parallel to the ground and at least one microphone disposed on a vertical line passing through the center point of the circle to sense noise from a surrounding noise source;
a sound source detection unit calculating information on a direction of the noise source and distance to the noise source using the microphone unit;
Based on the direction of the noise source calculated by the sound source detection unit, a panning and tilting angle for rotating the pan/tilt zoom camera is calculated so that the pan/tilt zoom camera faces the noise source, and the calculation a camera angle control unit controlling the pan/tilt zoom camera to rotate the pan/tilt angle to capture the area where the noise is generated;
a camera zoom control unit that proportionally calculates a zoom-control value of the pan/tilt zoom camera according to the tilt angle calculated by the camera angle control unit and controls the zoom of the pan/tilt zoom camera; and when the direction information and distance information of the noise source are continuously detected with a time difference, and when there are a plurality of heights on the ground of the noise source calculated using the direction information and distance information of the noise source, the height is preset A noise source higher than the height is judged to be in the dead zone position by the reflected noise source, and the direction of the noise source belonging to the dead zone is not provided to the camera angle control unit and the camera zoom control unit, thereby ignoring reflected and detected noise. having a zone processing unit,
The dead zone processing unit, even if the calculated direction of the noise source belongs to a preset dead zone, if other noise sources are not continuously calculated within a time period before and after a preset range, the direction of the noise source belonging to the dead zone is determined by the camera A CCTV system for crime prevention, characterized in that it provides the angle control unit and the camera zoom control unit.
The method of claim 1,
The dead zone is a CCTV system for crime prevention, characterized in that it is set as an area with a fixed structure.
The method of claim 1,
When the sound source detection unit calculates the distance to the noise source by using the microphone unit, the dead zone processing unit receives distance information from the sound source detection unit to the noise source along with direction information of the noise source, and the noise source is on the ground After calculating the height, if the calculated height on the ground of the noise source is greater than or equal to a preset reference height (Y), the CCTV system for crime prevention, characterized in that it is determined to belong to the dead zone.
In the surveillance method of a crime prevention CCTV system,
The first microphone unit having four microphones arranged at intervals of 90° along the circumference of a virtual circle parallel to the ground and two microphones arranged vertically on a vertical line passing through the center point of the circle detects the noise of the ambient noise source. step;
a second step of calculating, by a sound source detection unit, a direction of the noise source using the noise detected by the microphone unit;
A camera angle control unit calculates panning and tilting angles for the pan/tilt zoom camera so that the pan/tilt zoom camera faces the noise source based on the direction of the noise source calculated by the sound source detection unit, and a third step of rotating the pan/tilt zoom camera by the calculated panning and tilting angles to control to photograph the area where the noise is generated;
a fourth step of controlling the zoom of the pan/tilt zoom camera by a camera zoom control unit calculating a zoom-control value of the pan/tilt zoom camera according to the tilt angle calculated by the camera angle control unit; and
When the sound source detection unit continuously detects the direction information and distance information of the noise source with a time difference, the dead zone processing unit has a plurality of heights on the ground of the noise source calculated using the direction information and distance information of the noise source. , determining that the noise source whose height is higher than the preset height is in the dead zone position by the reflected noise source, and ignoring the third and fourth steps without performing the third and fourth steps for the noise source belonging to the dead zone, , the dead zone processing unit, even when the calculated direction of the noise source belongs to a preset dead zone, if other noise sources are not continuously calculated within a time period before and after a preset range, the direction of the noise source belonging to the dead zone A method of monitoring a CCTV system for crime prevention, characterized in that performing the third and fourth steps.

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