KR102273446B1 - Video surveillance system using magnetic sensor with detection area designation structure - Google Patents

Abstract

The present invention relates to a video surveillance system using a magnetic sensor with a detection area designation structure and, more specifically, to a video surveillance system using a magnetic sensor with a detection area designation structure, which sets a detection area by using a plurality of geomagnetic sensors, detects a visitor who possesses a small magnetic material threatening security among visitors passing through such a detection area on the basis of output of the geomagnetic sensors, and track the corresponding visitor through video analysis. According to the present invention, the video surveillance system can accurately detect the presence or absence of small magnetic materials such as pistols, knives, and unauthorized small devices by using a plurality of geomagnetic sensors for a visitor who passes through a detection area, in which security is required, while possessing the small magnetic material, can detect the visitor carrying such the small magnetic material as a suspect of criminal activity, and block the criminal activity of the suspect by tracking the suspect through video provided by one or more cameras, thereby providing effects of greatly increasing security of an area in which security is required and increasing reliability of blocking criminal activity. The video surveillance system comprises a detection device, at least one camera, and a video monitoring server.

Description

Video surveillance system using magnetic sensor with detection area designation structure

The present invention relates to an image monitoring system using a magnetic sensor having a detection area designation structure, and more particularly, to a small size that is a threat to security among those who pass through the detection area by designating a detection area using a plurality of geomagnetic sensors. To a video surveillance system using a magnetic sensor having a detection area designation structure that detects an occupant carrying a magnetic material based on the output of the geomagnetic sensor and then tracks the entrant through image analysis.

Recently, as crimes such as terrorism and industrial espionage have increased, the introduction of a security system to prevent suspects with criminal intent that threatens security in advance is increasing.

Most of the existing security systems install cameras in the security area, and through video analysis of the images received from these cameras, identify and track objects that are suspects taking actions that threaten security to prevent criminal actions in advance. operates to block

However, the security system using only the camera is difficult to detect even the items possessed by the suspect, so when the suspect commits a criminal act using the item that threatens security, the suspect is detected as a criminal, so it is practically a crime There is a problem in that it is difficult to block actions in advance.

Therefore, in order to compensate for this, a separate operation of a security checkpoint using X-rays is intended to detect a suspect possessing unauthorized belongings among the belongings of the suspect, but if such a security checkpoint is fixedly installed in a designated location, The location change is not easy, the search range is extremely limited, so efficiency is low, and the cost is high, so it is not suitable for a place where it is necessary to introduce a security system that targets multiple security areas.

Korean Patent Registration No. 10-1997236

The present invention forms a detection area using a plurality of geomagnetic sensors configured to designate a detection area, and secures security by holding small belongings such as a pistol or knife that exhibit magnetism that poses a threat to security among those who pass through the detection area The purpose of this is to support the accurate detection of a suspect that may be a threat to the public, and to prevent security threats in advance by acquiring images of the detected suspect through a plurality of cameras and performing tracking.

An image monitoring system using a magnetic sensor having a detection area designation structure according to an embodiment of the present invention is a magnetoresistive element pair having two magnetoresistive elements, and a magnetic material passing through a detection area between a first point and a second point A first pair disposed at the first point so that the measurement axis is in the +x-axis direction toward the second point, and the second point so that the measurement axis is in the -x-axis direction to detect the second pair, the third pair arranged at the first point so that the measurement axis faces the +y direction perpendicular to the +x axis, and the second pair so that the measurement axis faces the -y axis direction perpendicular to the -x axis A fourth pair disposed at the second point, a fifth pair disposed at the first point, such that the measurement axis faces the +z direction perpendicular to the +x axis and the +y axis, and the measurement axis faces the -z axis direction The sensor unit including a sixth pair disposed at the second point and the detection when there is a change in the output of the first pair, the second pair, the third pair, the fourth pair, the fifth pair, and the sixth pair A sensing device including a detection unit that determines that there is a moving magnetic material in the area, and generates and transmits event information, one or more cameras that capture the detection area and transmit an image generated through the detection unit and the camera and a communication network An image of communicating and detecting an object corresponding to a person whose magnetic body is sensed according to the event information from an image corresponding to an event occurrence time according to the event information among the images received from the one or more cameras when the event information is received from the detection unit a control server, wherein the detection unit includes: a first differential amplifier for differentially amplifying the output node voltages of the first pair and the second pair; and a first differential amplifier for differentially amplifying the output node voltages of the third pair and the fourth pair. A second differential amplifier, a third differential amplifier for differentially amplifying the output node voltages of the fifth pair and the sixth pair, the first differential amplifier, the second differential amplifier, and a third differential amplifier can be selected. When the output of any two differential amplifiers in the It may be characterized in that it includes an analysis unit that determines that there is a moving magnetic body.

As an example related to the present invention, if the Euclidean Norm obtained by the output of the first differential amplifier and the output of the second differential amplifier is greater than or equal to a preset reference value, the analysis unit determines that there is a magnetic material moving in the sensing area. can do.

As an example related to the present invention, the detection unit further includes an in-phase mode detection unit that determines an in-phase mode when signals having the same magnitude and the same sign are output from the first pair and the second pair, and the in-phase mode may be characterized in that a change in a magnetic field as a result of movement of a large magnetic body outside the sensing region acts on the sensing region.

As an example related to the present invention, if the Euclidean Norm obtained from the output of the first differential amplifier, the output of the second differential amplifier, and the output of the third differential amplifier is greater than or equal to a preset reference value, the magnetic body moving in the sensing area is It can be characterized by judging that there is.

As an example related to the present invention, the sensor unit includes a first sensor module and a second sensor module, the first pair, the third pair, and the fifth pair are built in the first sensor module, and the second pair and a fourth pair and a sixth pair are embedded in the second sensor module, and at least one of the +x, -x, +y and -y axial directions is formed on the outer surface of the case of the first sensor module and the second sensor module. It may be characterized in that it is visually displayed.

As an example related to the present invention, each of the first sensor module and the second sensor module is implemented as a wireless device and is wirelessly connected to the detection unit, and the first pair, the second pair, the third pair, the fourth pair, The output of the fifth pair and the sixth pair may be converted into a digital signal and transmitted to the detector.

As an example related to the present invention, the video monitoring system is configured in at least one of the video control server and the detection unit to check previously registered or separately received license information. It may further include a sensor detection interlocking software unit that provides sensor information to be used in the image control server according to a preset protocol.

As an example related to the present invention, in addition to the one or more cameras, one or more auxiliary cameras for transmitting an image generated by photographing a region of interest other than the detection region are further included, wherein the video control server communicates with the one or more auxiliary cameras It may be characterized in that it communicates through and detects the same object as the object in the image transmitted by each of the one or more auxiliary cameras.

As an example related to the present invention, the image control server extracts and stores the feature points for the object through image analysis, and based on the extracted feature points, from each of the one or more images corresponding to the one or more auxiliary cameras. It may be characterized in that the object and the same object are identified.

The present invention can accurately detect whether a small magnetic material such as a pistol, a knife, or an unauthorized small device is possessed by a plurality of geomagnetic sensors for a person who passes through a detection area requiring security while possessing a small magnetic material. , it is possible to detect a person carrying such a small magnetic body as a suspect suspected of criminal activity and then track the suspect through the image provided by one or more cameras to block the criminal activity of the suspect in advance. It can greatly increase security and has the effect of increasing the reliability of the pre-blocking of criminal activities.

In addition, the present invention can provide the convenience of changing the sensing area by conveniently setting the sensing area at the desired place by simply placing a plurality of geomagnetic sensors that are light and easy to move and install at the desired place. In addition, by supporting the accurate detection of small magnetic substances that threaten security through the output of a plurality of geomagnetic sensors, there is an effect of supporting the construction of a security system that can easily prevent crimes in advance at low cost.

1 is a block diagram of an image monitoring system using a magnetic sensor having a detection area designation structure according to an embodiment of the present invention;
2 is an overall configuration diagram of a small metal sensing device using a geomagnetic sensor of the present invention.
3 is a block diagram for explaining the operation of the sensing device of the present invention.
4 is a view for explaining a bridge offset structure.
5 is a view showing a sensing device according to another embodiment of the present invention.
6 is a view showing the sensing device of the present invention installed in the passage.
7 is a flowchart provided for explaining a method for detecting a magnetic body of a sensing device according to the present invention.
8 is a view showing a sensing device according to another embodiment of the present invention.
9 is an exemplary operation view of an image monitoring system using a magnetic sensor having a detection area designation structure according to an embodiment of the present invention.

Hereinafter, detailed embodiments of the present invention will be described with reference to the drawings.

1 is a block diagram of an image monitoring system (hereinafter, referred to as an image monitoring system) using a magnetic sensor having a detection area designation structure according to an embodiment of the present invention.

As shown, the video monitoring system according to an embodiment of the present invention may include a sensor unit 205 , a detection unit 250 , one or more cameras 10 , and an image control server 100 .

In this case, the video control server 100 may communicate with the detection unit 250 and the one or more cameras 10 through a communication network.

In addition, the communication network described in the present invention may include a wired/wireless communication network, and as an example of such a wireless communication network, a wireless LAN (WLAN), a DLNA (Digital Living Network Alliance), a WiBro (Wireless Broadband: Wibro), Wimax (World Interoperability for Microwave Access: Wimax), GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), CDMA2000 (Code Division Multi Access 2000), EV-DO (Enhanced Voice-Data Optimized or Enhanced Voice- Data Only), Wideband CDMA (WCDMA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), IEEE 802.16, Long Term Evolution (LTE), Long Term Evolution-A (LTE-A) Advanced), Wireless Mobile Broadband Service (WMBS), 5G mobile communication service, Bluetooth (Bluetooth), LoRa (Long Range), RFID (Radio Frequency Identification), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, Near Field Communication (NFC), Ultra Sound Communication (USC), Visible Light Communication (VLC), Wi-Fi, Wi-Fi Direct may be included. In addition, wired communication networks include wired LAN (Local Area Network), wired WAN (Wide Area Network), Power Line Communication (PLC), USB communication, Ethernet, serial communication, optical/coaxial cables, etc. may be included.

The sensor unit 205 includes a first sensor module 210 and a second sensor module 230 including a geomagnetic sensor, and the first sensor module 210 and the second sensor module 230 include a sensing area. It is configured adjacent to (or a measurement area or a detection target area) and may provide an output for detecting an occupant passing through the detection area to the detection unit 250 .

In addition, the detection unit 250 may detect the small magnetic body by sensing the small magnetic body from the output when the entrant possesses the small magnetic body.

In addition, the detection unit 250 may generate event information according to the detection of the small magnetic body when the small magnetic body is detected and transmit it to the image control server 100 through a communication network.

Also, the one or more cameras 10 may use the detection area as a photographing target area to generate an image of a person passing through the detection area, and then transmit it to the image control server 100 through a communication network.

In addition, the video control server 100 identifies an event occurrence time according to the event information when receiving event information from the detection unit 250 , and corresponds to the event occurrence time among the images received from the one or more cameras 10 . image can be identified.

In addition, the image control server 100 identifies an object corresponding to a suspect who is an entrant whose small magnetic body corresponding to the event information is detected (detected) in the image identified corresponding to the event occurrence time according to the event information. can be detected, and the detected object can be tracked.

As described above, the video surveillance system according to an embodiment of the present invention is configured to accurately detect an entrant with a small magnetic metal object as a suspect using a plurality of geomagnetic sensors to block the suspect's crime in advance. However, based on the above-described configuration, the present invention will be described in more detail with reference to the drawings below.

First, the configuration of the sensor unit 205 and the detection unit 250 constituting the video surveillance system of the present invention and capable of detecting a small metal object with high precision will be described.

In this case, the sensor unit 205 and the detection unit 250 may be configured as components included in the sensing device 200 for detecting an occupant carrying a small magnetic material for a designated sensing area, and the sensing device 200 is It may be configured to be included in the video surveillance system.

In addition, the detection unit 250 may be configured to be included in the sensor unit 205 .

2 and 3 , the sensing device 200 including a plurality of geomagnetic sensors includes a sensor unit 205 and a detection unit including a first sensor module 210 and a second sensor module 230 . A magnetic body of a person passing through the sensing area, including 250 , may be detected.

At this time, since the sensing method by the sensing device recognizes the change in the magnetic field due to the movement of the magnetic material that is generated according to the movement of the occupant, it is strictly to detect the movement of the magnetic material, but to recognize the magnetic material fixedly installed in the sensing area. no. Therefore, even if it is simply described as 'sensing a magnetic material' below, it should be understood that the movement of the magnetic material or sensing the moving magnetic material.

The first sensor module 210 and the second sensor module 230 are sensors for measuring a change in a magnetic field, respectively, and an output is connected to the detection unit 250 . The first sensor module 210 is installed at a first point p1, the second sensor module 230 is installed at a second point p2 spaced apart from the first point p1, and the first sensor module ( A space between the 210 and the second sensor module 230 becomes the sensing area. Meanwhile, here, the first point p1 and the second point p2 are points in space.

Here, for convenience of description, a sensing region set by three mutually perpendicular axes (x, y, z) will be described. Operations of the first sensor module 210 and the second sensor module 230 may be described based on three axes (x, y, z) set in the real space. In the present invention, since the x-axis is a basic measurement line, the first point p1 and the second point p2 are arranged on the x-axis.

In the present invention, two axes (x, y) or three axes (x, y, z) are set by installing the first sensor module 210 and the second sensor module 230 in an actual space. Therefore, x, y, and z are virtual coordinates for displaying the detection area set in the real space. In order to set the sensing area in the real space, directions of two or three axes are set in each of the first sensor module 210 and the second sensor module 230 . The first sensor module 210 is set in +x, +y, +z directions (or +x and +y directions), and the second sensor module 230 is configured in the -x, -y, -z directions (or -x and -y directions) are set. In order to set the x-axis as a measurement reference, +x of the first sensor module 210 and -x of the second sensor module 230 are arranged on the same axis to set the x-axis, and +y and -y are set on the same plane. Set the y-axis by placing it on the (xy plane). Accordingly, the three axes (x, y, z) are set in the real space according to the posture in which the first sensor module 210 and the second sensor module 230 are installed in the real space. According to an embodiment, at least one of +x, -x, +y, and -y axis directions may be visually displayed on the outer surfaces of the cases of the first sensor module 210 and the second sensor module 230 . For example, arrows 210a and 230a indicating the y-axis direction are displayed on the first sensor module 210 and the second sensor module 230 of FIG. 6 .

When the detection area defined by the x, y, and z axes (or x, y axes) is set in real space, the xy planes by the x and y axes do not need to be parallel to the ground or the floor of the passage, but the xy plane It can be easily and practically measured by setting it parallel to the ground or floor. In addition, since the x-axis is the basic measurement line, it is recommended to set the x-axis in the optimal direction for magnetic material detection in the x-y plane.

The hatched portion in FIG. 2 shows the plane of the passage through which a person can pass, and is an example in which the bottom surface of the passage is set parallel to the x-y plane. In addition, when the magnetic material moves along the passage, as shown in FIG. 2 , it is the closest method of recognizing the magnetic material that the x-axis vertically crosses the passage direction (arrow). However, of course, the x-axis may be set to cross the passage at an angle, and the x-y plane may not be horizontal to the passage.

Since the sensing device 200 of the present invention uses a distance within approximately 1 to 2 meters as the sensing area, it is preferable that the first point p1 and the second point p2 be spaced apart by approximately 1 to 2 meters. For example, as shown in FIG. 6 , the first sensor module 210 and the second sensor module 230 may be disposed on both sides of the 1-meter-wide passage to detect a small magnetic body passing through the passage. On the other hand, the first point p1 and the second point p2 are installed on the x-axis, and +x of the first sensor module 210 and -x of the second sensor module 230 are arranged on the x-axis. Although it is good, there may be errors that may occur during actual installation, and even if there is a slight discrepancy beyond the error range, there is no problem in the operation of the present invention because individual magnetoresistive elements do not have a problem in recognizing the change in the magnetic field.

The first sensor module 210 and the second sensor module 230 each include a plurality of magnetoresistive element pairs, and may include two magnetoresistive element pairs as in FIG. 3 , or three magnetoresistive element pairs as in FIG. 5 . It may include a magnetoresistive element pair. In the example of FIG. 3 , the first sensor module 210 includes a first pair 211 and a third pair 213 that are two magnetoresistive element pairs connected in series, and the second sensor module 230 includes a second magnetoresistive element pair. It includes a second pair 231 and a fourth pair 233 . The first to fourth pairs 211 , 213 , 231 , and 233 are electrically connected by using the same GND. As will be described below, the detection unit 250 differentially amplifies the output of the first pair 211 and the output of the second pair 231 , and the output of the third pair 213 and the output of the fourth pair 233 . By differentially amplifying, a change in the magnetic field in the sensing region between the first sensor module 210 and the second sensor module 230 is sensed.

In this case, the magnetoresistive element pair may include two magnetoresistive elements connected in series between the operating power supply VCC and GND.

In addition, the two magnetoresistive elements connected in series, each included in the first to fourth pairs 211 , 213 , 231 , and 233 , change the magnitude of the resistance in response to a change in the external magnetic field, and generate an output terminal by voltage distribution. The voltage of the connected node changes. On the other hand, the first to fourth pairs (211, 213, 231, 233) each measurement axis (Measurement Axis) in the same manner as known in the prior art according to the location and the node to which the operating power is supplied and the arrangement direction of the magnetoresistive element. this is decided

The first pair 211 outputs Vout 1 from the output terminal according to the change of the magnetic field, the second pair 231 outputs Vout 2 from the output terminal according to the change of the magnetic field, and the third pair 213 has the magnetic field Vout 3 is output from the output terminal according to the change of , and the fourth pair 233 outputs Vout 4 from the output terminal according to the change of the magnetic field.

In the first sensor module 210, the first pair 211 is arranged so that the direction of the measurement axis is +x-axis direction, and the third pair 213 has the direction of the measurement axis +y placed in the axial direction. In the second sensor module 230 , the second pair 231 is arranged so that the direction of its measurement axis becomes the -x-axis direction, and the fourth pair 233 is arranged so that the direction of its measurement axis becomes the -y-axis direction. do.

In order to set the virtual space by the x-axis, y-axis, and z-axis in the real space, the +x-axis direction of the first pair 211 and the -x-axis direction of the second pair 231 are the same as in FIG. 3 . It is arranged on one axis (x-axis). However, although the +y-axis direction of the third pair 213 and the -y-axis direction of the fourth pair 233 are disposed on the same x-y plane, they are not located on the same axis due to the measurement axis offset described below.

Meanwhile, the first sensor module and the second sensor module may each include three magnetoresistive element pairs to set the x, y, and z axes in the sensing area and measure the change in the magnetic field in the three directions. In the sensing device 500 of FIG. 5 , the first sensor module 510 and the second sensor module 530 each include three magnetoresistive element pairs, and the first sensor module 510 includes the first sensor module ( The fifth pair 511 is further included in the 210 , and the second sensor module 530 further includes a sixth pair 531 in the second sensor module 230 . The fifth pair 511 has a +z axis as a measurement axis and outputs Vout 5 from an output terminal, and the sixth pair 531 has a -z axis as a measurement axis and outputs Vout 6 from an output terminal.

On the other hand, each of the first sensor module 210 and the second sensor module 230 may be provided with a separate case, in addition to the first to fourth pairs (211, 213, 231, 233) to supply power to them. A DC power supply circuit for

The detection unit 250 detects the change in the magnetic field in the x-axis and the y-axis using Vout 1 and Vout 3 that are the outputs of the first sensor module 210 and Vout 2 and Vout 4 that are the outputs of the second sensor module 230 . A magnetic body is detected by recognizing it. Since there is a change in the magnetic field in the sensing region just by having a meaningful change in the output of at least one of Vout 1, Vout 2, Vout 3 and Vout 4, the first sensor module 210 and the second sensor module ( 230), there may be various methods for recognizing the change in the magnetic field using the output.

For example, the detection unit 250 includes the first differential amplifier 251 , the second differential amplifier 253 , and the analysis unit 255 to differentially amplify the signal for each axis to detect the magnetic material. The first differential amplifier 251 receives the output Vout 1 of the first pair 211 and the output Vout 2 of the second pair 231 and outputs the differentially amplified signal to the analyzer 255 . The second differential amplifier 253 receives the output Vout 3 of the third pair 213 and the output Vout 4 of the fourth pair 233 and outputs the differentially amplified signal to the analysis unit 255 . Since the present invention is for detecting a change in a micro-magnetic field in a sensing region, Vout 1, Vout 2, Vout 3, and Vout 4 themselves are inevitably weak. Accordingly, the present invention differentially amplifies the minute outputs of the first sensor module 210 and the second sensor module 230 using the first differential amplifier 251 and the second differential amplifier 253 .

The first differential amplifier 251 and the second differential amplifier 253 may use a known differential amplifier circuit, but may be implemented in software by a digital signal processing processor such as a DSP (Digital Signal Processing) chip. may be

The analysis unit 255 detects a magnetic material using the output signals of the first differential amplifier 251 and the second differential amplifier 253 . For example, if the output of the first differential amplifier 251 and/or the second differential amplifier 253 is greater than or equal to a predetermined reference value, the analysis unit 255 may determine that there is a magnetic material in the sensing area. . As another method, since the outputs of the first differential amplifier 251 and the second differential amplifier 253 are outputs of different direction vectors, the first differential amplifier 251 and the second differential amplifier 253 are By obtaining the Euclidean Norm of the output, the magnetic material can be recognized by whether it is greater than or equal to the reference value. In addition, when the signals of the first differential amplifier 251 and the second differential amplifier 253 do not reach the reference value, the analysis unit 255 may process it as noise.

The analysis unit 255 may be implemented as a general logic circuit, may be implemented in software by a digital signal processing processor such as a DSP chip, or may be implemented in software operating on a separate operating system program.

If the first sensor module 210 and the second sensor module 230 include three magnetoresistive element pairs as shown in FIG. 5 , the detection unit 250 may output the fifth pair 511 and the sixth pair A third differential amplifier 551 for differentially amplifying the output of 531 may be further included. In addition, the analysis unit 255 detects the magnetic material by using the output signals of the first differential amplifier 251, the second differential amplifier 253, and the third differential amplifier 551.

Hereinafter, a method for detecting a magnetic body using the first sensor module 210 and the second sensor module 230 of the present invention will be described.

Spatial Measurement Using Bridge Offset

Referring to FIG. 4 , the first pair 211 and the second pair 231 have a bridge shape and are differentially amplified by the first differential amplifier 251 . In this case, the first pair 211 and the second pair 231 are disposed to be spatially spaced apart by a bridge offset distance. According to this arrangement, the bridge offset space becomes the sensing region, and it is possible to amplify minute changes in the magnetic field within the sensing region. Furthermore, due to the bridge offset, the change in the magnetic field by the large magnetic material located outside the measurement space acts in the same direction with almost the same magnitude for the first pair 211 and the second pair 231 (Common mode) acts as

Accordingly, the change in the magnetic field in the sensing region acts in different directions with respect to the first pair 211 and the second pair 231 , so that the output Vout 1 of the first pair 211 and the output of the second pair 231 . Vout 2 is a signal with different codes. Accordingly, while Vout 1 and Vout 2 are differentially amplified by the first differential amplifier 251 , the output of the magnetoresistive element is amplified by a minute change in the magnetic field. When the magnitude of the output of the first differential amplifier 251 is equal to or greater than the reference value, the analysis unit 255 recognizes the magnetic material. The bridge offset prevents a sudden loss of a signal due to an increase in the distance between the magnetoresistive element and the point where the magnetic field change occurs, and no matter where the magnetic field change occurs at any position on the path, a signal with no significant loss can be obtained.

If there is no space between the first pair 211 and the second pair 231 and the change in the magnetic field close to the first pair 211 and the second pair 231 is Since the two pairs 231 act in the same direction, the output Vout 1 of the first pair 211 and the output Vout 2 of the second pair 231 are signals of the same sign. By the first differential amplifier 251, Vout 1 and Vout 2 cancel each other out in the differential amplification process, and the detection sensitivity is rather reduced.

In the common mode, although outside the sensing region, since the change in the external magnetic field is very large, the output Vout 1 of the first pair 211 and the output Vout 2 of the second pair 231 have almost the same magnitude and the same sign. becomes a signal of Accordingly, since Vout 1 and Vout 2 are differentially amplified and cancel each other, the output of the first differential amplifier 251 is almost absent.

As such, there is no output of the first differential amplifier 251 in the common mode due to the bridge offset, but according to an embodiment, the analysis unit 255 uses the outputs of the first pair 211 and the second pair 231 . Thus, it may further include a common mode detection unit (not shown) for detecting the common mode output. For example, the common mode detection unit may determine that there is a change in the magnetic field of the common mode when the output Vout 1 of the first pair 211 and the output Vout 2 of the second pair 231 are added to a certain level or more. .

Measure the gradient of the magnetic field using the offset of the measuring axis

The signal of magnetic field change that appears when an object made of iron moves is divided into a permanent magnetization component and an induction magnetization component, and the magnetization component changes the gradient of the surrounding magnetic field. When only the first pair 211 and the second pair 231 are installed, it is difficult to measure the gradient of the magnetic field along the y-axis. In the present invention, a third pair 213 and a fourth pair 233 are additionally provided to measure the gradient (change) of the magnetic field in the y-axis direction.

Referring to FIG. 3 , unlike the measurement axes of the first pair 211 and the second pair 231 being disposed on the x-axis, the measurement axes of the third pair 213 and the fourth pair 233 +y A 'measurement axis offset' is placed between and -y.

If the measurement axis offset structure is used, the change in the magnetic field including the gradient of the magnetic field in the y-axis direction in the sensing area can be measured. Since it is advantageous to measure the gradient of the magnetic field in a spatially separated state, the third pair 213 and the fourth pair 233 may sense a change in the gradient of the micro magnetic field by the measurement axis offset.

In addition, since the third pair 213 and the fourth pair 233 are spaced apart by the measurement axis offset, a passage path in the y-axis direction can be secured. In other words, when the x-axis is set to cross the passage, the third pair 213 and the fourth pair 233 do not need to be disposed on the passage.

In the present invention, the third pair 213 and the fourth pair 233 to which the measurement axis offset is applied are simultaneously applied together with the change in the magnetic field of the x-axis component by the first pair 211 and the second pair 231 . By doing so, it is possible to improve the sensitivity to changes in the micro-magnetic field in the sensing region.

Sensor module with 3-axis magnetoresistive element pair

The first sensor module 510 and the second sensor module 530 of FIG. 5 set a sensing area in three axes of x, y, and z and measure a change in a magnetic field in the three axes. Accordingly, the first sensor module 510 further includes a fifth pair 511 in the first sensor module 210 , and the second sensor module 530 includes a sixth pair 531 in the second sensor module 230 . further includes

As if there is a 'measurement axis offset' between the measurement axes +y and -y of the third pair 213 and the fourth pair 233, the first sensor module 510 is placed at the first point p1 and the second When the sensor module 530 is placed at the second point p2 , a measurement axis offset is also generated between the +z axis of the fifth pair 511 and the -z axis of the sixth pair 531 . Accordingly, the fifth pair 511 and the sixth pair 531 may measure the gradient of the magnetic field change in the z-axis direction. Similarly, when the change of the external magnetic field is applied to the third pair 213 and the fourth pair 233 in the in-phase mode, the fifth pair 511 and the sixth pair 531 are also applied to the in-phase mode.

The detection unit 550 of the sensing device 500 of FIG. 5 further includes a third differential amplifier 551 in addition to the first differential amplifier 251 and the second differential amplifier 253 . The third differential amplifier 551 receives Vout 5 output from the fifth pair 511 and Vout 6 output from the sixth pair 531 , and provides a differentially amplified signal to the analyzer 255 .

The analysis unit 255 determines that the magnetic material has been recognized if the size of the output of any one of the first differential amplifier 251, the second differential amplifier 253, and the third differential amplifier 551 is greater than or equal to the reference value. When all of the outputs of the first differential amplifier 251, the second differential amplifier 253, and the third differential amplifier 551 are individually greater than or equal to a predetermined reference value, it can be determined that the magnetic material has been recognized. may be As another method, the analysis unit 255 calculates the Euclidean Norm of the square of the output of each of the first differential amplifier 251 , the second differential amplifier 253 , and the third differential amplifier 551 . If the sum (or the square root of the sum) is equal to or greater than the reference value, it may be determined that the magnetic material has been recognized.

Alternatively, the analysis unit 255 detects the output of any two differential amplifiers that can be selected from the first differential amplifier 251, the second differential amplifier 253, and the third differential amplifier 551. It may be determined that there is a magnetic material moving in the sensing area when the magnitude of the output of the two differential amplifiers is equal to or greater than a reference value.

According to an embodiment, the detection unit 550 of FIG. 5 may further include an in-phase mode detection unit. The common mode detection unit determines whether the output Vout 1 of the first pair 211 and the output Vout 2 of the second pair 231 are equal to or greater than a certain level by adding the output Vout 3 of the third pair 213 and the output Vout 3 of the fourth pair 233 ) by adding the output Vout 4 to determine whether it is greater than or equal to a certain size, or by adding the output Vout 5 of the fifth pair 511 and the output Vout 6 of the sixth pair 531 to determine whether it is greater than or equal to a certain level, so that the change in the magnetic field is in phase mode can be determined.

Meanwhile, the present invention also extends to the sensing method of the sensing devices 200 and 500 described with reference to FIGS. 2 to 6 .

As shown in FIG. 7 , in the sensing method of the sensing device according to the present invention, a plurality of magnetoresistive element pairs 211 , 213 , 231 , 233 , 511 , 531 are combined with a bridge offset and a measurement axis according to FIGS. 3 and 5 . In the step of installing an offset in the sensing region (S701), the outputs of the magnetoresistive element pairs 211, 213, 231, 233, 511, 531 are differentially applied to the first to third differential amplifiers 251, 253, and 551. A step of amplifying (S703), and the analysis unit 255 determining whether there is a change in the magnetic field according to the movement of the magnetic material in the sensing region based on the outputs of the first to third differential amplifiers 251, 253, 551 ( S705).

Wireless connection between the first sensor module 210 and the second sensor module 230

On the other hand, the first sensor module 210 and the second sensor module 230 of the present invention may be implemented as a wireless device so as to be easily installed in the sensing area.

Referring to FIG. 8 , the first sensor module 810 and the second sensor module 830 are connected to the detector 850 through a wireless channel such as Bluetooth or a wireless LAN channel, and the first to fourth pairs 211, The outputs of 213 , 231 , and 233 may be converted into analog signals or digital signals and provided to the detection unit 850 .

In order to convert the outputs of the first to fourth pairs 211 , 213 , 231 , and 233 into digital signals, the first sensor module 810 receives the outputs of the first pair 211 and the third pair 231 , respectively. First and third amplifiers 811 and 813 for amplifying, a first converter 815 for converting the amplified signal into a digital signal, and a first for transmitting the output of the first converter 815 to the detection unit 850 and a wireless interface 817 . Similarly, the second sensor module 830 includes second and fourth amplifiers 831 and 833 for amplifying the outputs of the second pair 213 and the fourth pair 233, respectively, and converts the amplified signal into a digital signal. a second converter 835 , and a second wireless interface 837 for transmitting the output of the second converter 835 to the detection unit 850 .

Correspondingly, the detection unit 850 also needs a third wireless interface 851 that can be connected to the first wireless interface 817 and the second wireless interface 837 . Meanwhile, when implemented as a wireless device, the first to fourth pairs 211 , 213 , 231 , and 233 cannot be connected to the same GND. Accordingly, the detector 850 sets reference values of the outputs of the first to fourth pairs 211 , 213 , 231 , and 233 , and the first to second differential amplifiers 853 and 855 use the first to fourth pairs Differential values of the output of (211, 213, 231, 233) are differentially amplified by software.

According to the above-described configuration of the sensing device, the first sensor module and the second sensor module configured in the sensor unit 205 of the sensing device are configured to allow a person passing through the sensing area to have a small magnetic body (or a small metal body). In this case, the output of detecting the small magnetic material may be provided to the detection unit.

In addition, the detection unit generates a first output obtained by differentially amplifying an output of a first pair provided by the first sensor module and an output of a second pair provided by the second sensor module, and provided by the first sensor module After generating a second output obtained by differentially amplifying the output of the third pair and the output of the fourth pair provided by the second sensor module, when at least one of the first output and the second output changes by more than a reference value, the visitor It can be determined and detected as possessing a small magnetic material that can become a security threat.

At this time, when a fifth pair is additionally configured in the first sensor module and a sixth pair is additionally configured in the second sensor module, the detection unit outputs the fifth pair and the sixth pair to the first sensor a module and a second sensor module, respectively, and may generate a third output obtained by differentially amplifying the output of the fifth pair and the output of the sixth pair, the first output, the second output, and the third output When there is a change in at least one of the reference values or more, it may be determined and detected that the entrant possesses a small magnetic material that may become a security threat.

In addition, the detection unit 250 determines that an event occurs when the small magnetic body is detected (detected), and generates event information including an event occurrence time, which is a time point at which the small magnetic body is detected, so that the image control server 100 can be sent to

The generation of the event information may be performed by an analysis unit included in the detection unit 250 .

In this case, the detection unit 250 may be configured to include a communication unit for communication with the video control server 100 through the communication network, and the communication unit may be configured to include the third air interface, and the first 3 A communication module for communication through the communication network separately from the wireless interface may be included in the communication unit.

In addition, the detection unit 250 includes output information including the first output and the second output in the event information or outputs information including the first output, the second output, and the third output to the event information. It may be included in the information and transmitted to the video control server 100 .

On the other hand, the video control server 100, based on the event information provided from the detection unit 250, when a suspect who is an occupant possessing a small magnetic material that is a security threat is detected, the suspect is tracked and the suspect's crime It can operate to block an action in advance, which will be described in detail with reference to FIG. 9 .

As shown, the image control server 100 receives the output from the sensor unit 205 and generates event information by receiving the event information from the detection unit 250, one or more cameras 10 for photographing the detection area. ), an image of interest that is an image corresponding to an event occurrence time included in the event information may be identified and extracted.

In this case, the video control server 100 includes a server communication unit for communication through a communication network with the detection unit 250 and the one or more cameras 10 , and for storing images received from each of the one or more cameras 10 . It may be configured to include a storage unit and a server control unit that controls the components configured in the video control server 100 and performs overall control functions of the video control server 100, but is not limited thereto, and various components are additionally configured. can be

In addition, at least one of the components configured in the video control server 100 may be configured by being included in another component.

In addition, the server control unit executes the overall control function of the image control server 100 using the program and data stored in the storage unit, and the server control unit may include RAM, ROM, CPU, GPU, and a bus. , RAM, ROM, CPU, GPU, etc. can be connected to each other via a bus.

Accordingly, the server control unit of the image control server 100 searches for the images received from the one or more cameras 10 stored in the storage unit based on the event occurrence time according to the event information, and according to the event information An image captured at the time of occurrence of an event may be selected as an image of interest and extracted from the storage unit.

The configuration of the image control server 100 to be described below may be performed by the server controller.

On the other hand, the image control server 100 may detect a specific object (or object of interest) corresponding to a suspect whose magnetic body is detected according to the event information from the image of interest corresponding to the time of occurrence of the event according to the event information. .

In this case, the image control server 100 may identify and detect the specific object from the image of interest through a preset image analysis algorithm.

In addition, the image control server 100 may receive the event information or generate alarm information corresponding to the event information when the specific object is detected (or identified) from the image of interest corresponding to the event information.

In addition, the video monitoring system may be configured to further include an alarm device including a warning light, a speaker, and the like.

In this case, the video control server 100 may communicate with the alarm device through a communication network, and may transmit the alarm information to the alarm device when generating the alarm information.

Accordingly, when the alarm information is received, the alarm device may generate a warning signal based on the alarm information and output the alarm information through a warning light or output a warning sound according to the alarm information through a speaker. .

Through this, the alarm device can notify the manager who controls the detection area that a suspect, who is an entrant carrying a magnetic material, has been detected in the detection area, thereby pre-blocking the suspect's criminal activity.

In addition, the image control server 100 may identify a specific object detected as a suspect in the image of interest, and extract a feature point from the specific object through a preset image analysis algorithm.

In addition, the image control server 100 identifies and detects the same object as the specific object in the image provided by another camera 10 other than the camera 10 that provided the image of interest based on the extracted feature point. It is possible to track the same object as the specific object.

For example, the image control server 100 identifies the face region of the specific object detected in the image of interest in correspondence to the event information, extracts the feature point from the face region, generates the feature point information, and the specific object The object identification information including the feature point information may be generated to correspond to , and stored in the storage unit.

In addition, in the storage unit of the image control server 100, occupant information including feature point information on feature points of the face region for each occupant with access authority may be pre-stored, and the image control server 100 may identify the object. By comparing the feature point information included in the information with the feature point information of the visitor information for each visitor stored in the storage unit, it is possible to identify the occupant information including the feature point information matching the feature point information of the specific object.

In addition, the image control server 100 may generate the alarm information and output it through the alarm device when the occupant information including the characteristic point information matching the characteristic point information of the specific object does not exist in the storage unit. .

In addition, the video surveillance system may be configured to further include one or more auxiliary cameras 20 for transmitting an image generated by photographing a region of interest other than the detection region.

In this case, the one or more auxiliary cameras 20 may be configured to photograph mutually different regions of interest.

Accordingly, the image control server 100 receives the image from each of the one or more auxiliary cameras 20, and when an object corresponding to a person is identified in the image for each auxiliary camera, extracting the characteristic point from the identified object Information can be generated and compared with feature point information of a specific object corresponding to the suspect.

At this time, when the specific object corresponding to the event information is identified from the image of interest and object identification information including the characteristic point information of the specific object is generated, the image control server 100 generates an object in each of the images for each of the one or more auxiliary cameras. After identifying and generating feature point information for the identified object, it is possible to perform tracking of the specific object while identifying the same object as the specific object by comparing it with feature point information included in the object identification information.

In addition, the image control server 100 may identify and detect an object in which key point information matching the key point information of the specific object is generated through the key point comparison in the image for each auxiliary camera.

Accordingly, the image control server 100 receives the same object as the object corresponding to the suspect detected in the image of interest corresponding to the detection area from the auxiliary camera 20 for photographing the area of interest other than the detection area. It can be detected in the image, and through this, it is possible to continuously track suspects detected as possessing a small magnetic body.

As an example, the image control server 100 generates object identification information for the specific object when detecting a specific object corresponding to the event information in the image of the camera 10 that captures the detection area, and stores it in the storage unit. can

In this case, the object identification information may include an ID given to the object by the image control server 100, occupant information including feature point information matching the feature point information of the specific object, and the feature point information.

In addition, when the video control server 100 identifies and detects the same object as the specific object corresponding to the suspect in the image of the specific auxiliary camera 20 among the one or more auxiliary cameras 20, the specific auxiliary camera ( 20), the preset location information of the ROI may be matched with object identification information of the specific object and stored.

In this case, the image control server 100 may match the location information of the ROI with the object identification information of the specific object and store it in the storage unit of the image control server 100 .

Through this, the video control server 100 sends an image in which the specific object is detected whenever an object identical to the specific object is identified from the image transmitted by the auxiliary camera 20 to the auxiliary camera 20 that transmits the detected image. The location information of the corresponding region of interest may be stored by matching with the object identification information of the specific object, and the movement path of the specific object may be tracked based on one or more pieces of location information accumulated by matching the specific object.

In this case, the video control server 100 may include the time (or time point) at which the specific object was detected in the location information when the location information is matched with the object identification information and stored, and the video control server 100 ) may be matched with the object identification information of the specific object to generate path information on a movement path according to a time sequence based on the accumulated stored location information and the time included in the location information.

Meanwhile, in the above-described configuration, the image control server 100 includes a first output obtained by differentially amplifying an output for the x-axis among the outputs provided by the first sensor module 210 and the second sensor module 230 and the Among the outputs provided by the first sensor module 210 and the second sensor module 230, a second output obtained by differentially amplifying the output for the y-axis is identified from the event information, and the first output and the second output are combined The output ranges for the x-axis and y-axis for each of the above object types can be compared with preset setting information.

In this case, the setting information may be preset or stored in the image control server 100 , and the output range may include a range for an output of an x-axis and a range for an output of a y-axis.

Accordingly, the image control server 100 compares the first output and the second output included in the event information with the setting information to determine the type of object corresponding to the output range to which the first output and the second output belong. It can be identified from the setting information.

Accordingly, the image control server 100 determines that at least one of the first output and the second output is equal to or greater than a reference value, and the object type identified in response to the event information is a pre-set object type as a dangerous object that threatens security. In this case, the alarm information may be generated and transmitted to the alarm device.

In this case, the event information may further include a third output obtained by differentially amplifying the output on the z-axis, and a range for the output of the z-axis may be further set in each of the output ranges for each object type included in the setting information. .

Accordingly, the video control server 100 compares the first output, the second output, and the third output included in the event information with the setting information to which the first output, the second output, and the third output belong. An object type corresponding to the output range can be identified from the setting information, and at least one of the first output, the second output, and the third output is greater than a reference value, and the object type identified in response to the event information is a threat to security In the case of a preset object type as a dangerous object, the alarm information may be generated and transmitted to the alarm device.

At this time, the video control server 100 may include the identified object type in the alarm information and transmit it to the alarm device, and the alarm device is configured as a display device and outputs a warning signal through the display device. An object type identified in correspondence to the event information may be displayed.

Meanwhile, in the above configuration, the video monitoring system is configured in at least one of the video control server 100 and the detection unit 250 to check previously registered or separately received license information, and if the check result is approved, the It may further include a sensor detection interlocking software unit that provides the sensor information detected by the detection unit 250 to be used by the image control server 100 according to a preset protocol.

As described above, the present invention uses a plurality of geomagnetic sensors to determine whether a small magnetic material such as a pistol, a knife, or an unauthorized small device is possessed by an entrant who passes through a sensing area requiring security while possessing a small magnetic material. It is possible to accurately detect a person carrying such a small magnetic material as a suspect suspected of criminal activity, and then track the suspect through the video provided by one or more cameras to block criminal activity of the suspect in advance. The security of this necessary area can be greatly increased, and the reliability of the pre-blocking of criminal activities can be increased.

In addition, the present invention can provide convenience for changing the sensing area by conveniently setting the sensing area at the desired place by simply placing a plurality of geomagnetic sensors that are light and easy to move and install at the desired place. In addition, by supporting the accurate detection of small magnetic objects that threaten security through the output of a plurality of geomagnetic sensors, it is possible to support the construction of a security system that can easily prevent crime in advance at low cost.

In addition, in the present invention, the sensing device for sensing a small magnetic body processes in a common mode even if a change in a magnetic field generated while a large metal body moves, such as a long-distance vehicle or an elevator, reaches the sensing area, and processes the small metal. It is possible to separate and detect minute changes in the magnetic field caused by movement. Similarly, since changes in the Earth's magnetic field that occur in natural phenomena such as sunspot explosion, magnetic axis movement, and magnetic storm are also processed as in-phase mode signals in the present invention, minute changes in magnetic field caused by small magnetic materials in the sensing area unaffected by the detection of

In addition, since the geomagnetic sensors included in the sensing device of the present invention are designed not to respond to changes in the magnetic field caused by the movement of a large magnetic body in the vicinity or changes in the Earth's magnetic field itself, microscopic The signal can be amplified by a large magnification.

In addition, the sensing device of the present invention is differentially amplified by applying a bridge offset and a measurement axis offset that extend the measurement point of the geomagnetic sensor to the measurement space and simultaneously measuring the change in the magnetic field gradient. , it is possible to sufficiently amplify minute changes in the magnetic field within the sensing area. Through this, the sensing device of the present invention solves the problem that the sensing signal rapidly decreases according to the distance between the sensor and the moving object in the sensing area.

The components described in the embodiments of the present invention include, for example, a storage unit such as a memory, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, and a field programmable (FPA). one or more general purpose computers or special devices, such as hardware such as an array), programmable logic unit (PLU), microprocessor, software including an instruction set, or any combination thereof, or any other device capable of executing and responding to instructions. It can be implemented using a target computer.

Those of ordinary skill in the art to which the present invention pertains may modify and modify the above-described contents without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

10: camera 20: secondary camera
100: video control server 200: detection device
205: sensor unit 210: first sensor module
230: second sensor module 250: detection unit

Claims (9)

As a magnetoresistive element pair having two magnetoresistive elements, in order to sense a magnetic material passing through a sensing area between a first point and a second point, a measurement axis is directed toward the second point in a +x-axis direction. a first pair disposed at the first point such that the second pair is disposed at the second point such that the measurement axis is in the -x axis direction, and the measurement axis is directed in the +y direction perpendicular to the +x axis. A third pair disposed at the first point, a fourth pair disposed at the second point such that the measurement axis faces the -y axis direction perpendicular to the -x axis, and the measurement axis is perpendicular to the +x and +y axes a sensor unit including a fifth pair disposed at the first point to face a +z direction and a sixth pair disposed at the second point so that a measurement axis faces a -z axis direction; and
When there is a change in the output of the first pair, the second pair, the third pair, the fourth pair, the fifth pair, and the sixth pair, it is determined that there is a moving magnetic material in the sensing area, and event information is generated and transmitted a detection unit;
A sensing device comprising;
one or more cameras for transmitting an image generated by photographing the detection area; and
A person who communicates with the detection unit and the camera through a communication network, and has detected a magnetic body according to the event information from an image corresponding to an event occurrence time according to the event information among the images received from the one or more cameras when receiving event information from the detection unit A video control server that detects an object corresponding to
includes,
The detection unit,
a first differential amplifier for differentially amplifying the output node voltages of the first pair and the second pair;
a second differential amplifier for differentially amplifying the output node voltages of the third pair and the fourth pair;
a third differential amplifier for differentially amplifying the output node voltages of the fifth pair and the sixth pair;
and
When the output of any two differential amplifiers selectable from the first differential amplifier, the second differential amplifier, and the third differential amplifier is sensed, it includes an analysis unit that determines that there is a magnetic body moving in the sensing area,
The detection unit,
In the case where the signal having the same magnitude and the same sign is output from the first pair and the second pair, it further includes an in-phase mode detection unit for judging an in-phase mode,
The in-phase mode is an image monitoring system using a magnetic sensor having a detection area designation structure, characterized in that a change in a magnetic field as a result of movement of a large magnetic body outside the detection area acts on the detection area.
The method according to claim 1,
The analysis unit determines that there is a magnetic material moving in the sensing area when the Euclidean Norm obtained by the output of the first differential amplifier and the output of the second differential amplifier is greater than or equal to a preset reference value. A video surveillance system using sensors.
delete The method according to claim 1,
If the Euclidean Norm obtained by the output of the first differential amplifier, the output of the second differential amplifier, and the output of the third differential amplifier is greater than or equal to a preset reference value, the analysis unit determines that there is a magnetic material moving in the sensing area. A video surveillance system using a magnetic sensor with a detection area designation structure.
The method according to claim 1,
The sensor unit includes a first sensor module and a second sensor module,
The first pair, the third pair, and the fifth pair are built in the first sensor module,
The second pair, the fourth pair, and the sixth pair are built into the second sensor module,
An image using a magnetic sensor having a detection area designation structure, wherein at least one of the +x, -x, +y and -y axial directions is visually displayed on the outer surfaces of the cases of the first sensor module and the second sensor module surveillance system.
6. The method of claim 5,
Each of the first sensor module and the second sensor module is implemented as a wireless device and is wirelessly connected to the detection unit,
The output of the first pair, the second pair, the third pair, the fourth pair, the fifth pair and the sixth pair is converted into a digital signal and transmitted to the detection unit. video surveillance system used.
The method according to claim 1,
It is configured in at least one of the video control server and the detection unit to check previously registered or separately received license information, and if use is approved as a result of the verification, the sensor information detected by the detection unit is used in the video control server according to a preset protocol. An image monitoring system using a magnetic sensor having a detection area designation structure, characterized in that it further comprises a sensor detection interlocking software unit that provides to be able to do so.
The method according to claim 1,
In addition to the one or more cameras, it further comprises one or more auxiliary cameras for transmitting an image generated by photographing a region of interest other than the detection region,
The image control server communicates with the one or more auxiliary cameras through a communication network, and a magnetic sensor having a detection area designation structure, characterized in that it identifies and detects the same object as the object in the image transmitted by each of the one or more auxiliary cameras video surveillance system using
9. The method of claim 8,
The video control server extracts and stores the feature points for the object through image analysis, and identifies the same object as the object from each of the one or more images corresponding to the one or more auxiliary cameras based on the extracted feature points A video surveillance system using a magnetic sensor with a characteristic detection area designation structure.

Images