KR102628412B1 - Monitoring method and system - Google Patents

Abstract

Embodiments of the present invention disclose a surveillance system and method.
A monitoring method according to an embodiment of the present invention includes tracking the detected object by a first camera that detects an object among a plurality of cameras monitoring each area within a first network; and monitoring the area of the first camera according to a priority set based on the similarity to the specifications of the first camera among candidate cameras assigned to an area with a surveillance importance lower than that of the area of the first camera. It includes; selecting a second camera to replace.

Description

Monitoring method and system {Monitoring method and system}

Embodiments of the present invention relate to surveillance systems and methods.

Pan-tilt-zoom (hereinafter referred to as PTZ) cameras respond to specific subjects or events and provide the ability to track specific subjects or intensively monitor and record the area where the event occurred. These features can cause blind spots by missing areas that were originally supposed to be monitored.

Korean Patent No. 1228341

When a PTZ camera tracks a subject or changes the PTZ value, the area originally to be monitored becomes a blind spot, making it impossible to obtain surveillance video for the surveillance area. As a result, if a problem occurs in that blind spot, important evidence cannot be secured.

Embodiments of the present invention seek to provide a surveillance method and system that can secure images of areas that become blind spots and organically use PTZ cameras for this purpose.

A monitoring method according to an embodiment of the present invention includes tracking the detected object by a first camera that detects an object among a plurality of cameras monitoring each area within a first network; and monitoring the area of the first camera according to a priority set based on the similarity to the specifications of the first camera among candidate cameras assigned to an area with a surveillance importance lower than that of the area of the first camera. It includes; selecting a second camera to replace.

The method selects a third camera to perform tracking of the object according to a priority set based on similarity to the specifications of the first camera among candidate cameras allocated to the area containing the predicted position of the object. Steps may be further included.

The method may further include requesting a profile change of the third camera based on the characteristics of the object.

The first camera may select the second camera and the third camera according to the priorities of cameras that responded to the surveillance replacement request or object tracking request among the candidate cameras.

The method may further include, when there is no candidate for the second camera among the cameras in the first network, constructing a third network with at least one of cameras in a second network different from the first network. You can.

In embodiments of the present invention, when one camera tracks a specific subject in an area where a PTZ camera is being used, the area of the tracking camera is adjusted to prevent blind spots from surrounding PTZ cameras through communication between cameras. A surveillance system and method can be provided that can automatically cover and modify the profiles of cameras in the area.

1 is a block diagram schematically showing a monitoring system according to an embodiment of the present invention.
Figure 2 is a block diagram schematically showing the internal structure of a camera according to an embodiment of the present invention.
3A to 3C show an example explaining a monitoring method according to an embodiment of the present invention.
Figure 4 is a diagram illustrating network construction of a surveillance system according to an embodiment of the present invention.
Figure 5 is a flowchart schematically explaining a monitoring method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Like symbols in the drawings refer to like elements. In describing the present invention below, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

1 is a block diagram schematically showing a monitoring system according to an embodiment of the present invention.

Referring to FIG. 1, the surveillance system according to an embodiment of the present invention includes a plurality of cameras 1 to N (101a to 101n) and a control device 130 connected to the plurality of cameras 1 to N (101a to 101n). It can be included.

A plurality of cameras 1 to n (101a to 101n) and the control device 130 may be connected to a communication network, for example, LAN or TCP/IP. Communication networks may include wired networks and wireless networks such as 3G, 4G (LTE), WiFi, Wibro, Wimax, etc.

The plurality of cameras 1 to n (101a to 101n) may be PTZ cameras arranged at a fixed location in a specific location and having pan/tilt/zoom functions. The camera can acquire various images by panning and/or tilting rotation by a driving device, or adjusting the zoom ratio by zooming in or zooming out the zoom lens. A plurality of cameras 1 to n (101a to 101n) are installed inside and outside of offices, houses, hospitals, as well as banks and public buildings requiring security, or outdoors such as parks, and can be straight or dome-shaped depending on the installation location and purpose of use. It can have various forms, such as:

Each of the plurality of cameras 1 to n (101a to 101n) may detect an object while monitoring an area allocated to it among the plurality of areas in which the surveillance area is divided using a preset method. At this time, in the preset method, the camera moves or rotates according to a preset preset to monitor the surveillance area. Each of the plurality of cameras 1 to n (101a to 101n) is connected to the control device 130 by wire or wirelessly and can transmit and receive images and control data. Each of the plurality of cameras 1 to n (101a to 101n) may be assigned an ID as its unique identification information. Each of the plurality of cameras 1 to n (101a to 101n) can store and manage information about cameras in the network in a table. Camera information may include the area allocated to each camera, camera specifications, priority, area importance, etc.

Each of the plurality of cameras 1 to n (101a to 101n) may track the object when an unauthorized object is detected and output an event occurrence signal to the control device 130 and/or cameras in the network.

If an object (for example, a person, a car, etc.) goes beyond the camera's monitoring range, monitoring becomes impossible, or if the object moves in a direction that can disable the camera's monitoring function, monitoring becomes impossible.

In one embodiment of the present invention, each of the plurality of cameras 1 to n (101a to 101n) collaborates to prevent the monitoring and tracking function of an object from being weakened. When an object is detected, each of the plurality of cameras 1 to n (101a to 101n) may select an alternative camera according to a priority set based on the area importance and/or camera specifications of the camera and other cameras. The replacement camera may include a second camera that will replace surveillance of the area assigned to the first camera that is detecting and tracking the object, and a third camera that will subsequently track the object outside the area of the first camera.

The control device 130 includes a wireless access point (AP) supporting the Wi-Fi communication method, a wireless base station supporting the LTE communication method, a relay device such as a gateway, and a relay, and a digital video recorder (DVR: It may be a recording device such as a digital video recorder (NVR) or a network video recorder (NVR), or a server such as a recording server, an upgrade server, or an alarm server.

The control device 130 can store and manage camera information for each of the plurality of cameras 1 to n (101a to 101n) in a table. The control device 130 may independently select the second camera and the third camera based on the request of the first camera or the monitoring situation of the first camera. The control device 130 may receive the object's movement speed and direction from the first camera, update the object's movement information, and select the third camera instead of the first camera.

Since the method of selecting the second camera and the third camera by the control device 130 is the same as the method of selecting the second camera and the third camera by the camera described later, description is omitted.

Although not shown, the surveillance system may further include a recording device, such as a digital video recorder (DVR) or a network video recorder (NVR), separate from the control device 130. The recording device can determine whether to record only keyframes or full frames of video signals received from cameras 1 to n (101a to 101n). When blind spots are eliminated, the recording device can record and play back the received video by processing it like a one-take video.

Figure 2 is a block diagram schematically showing the internal structure of a camera according to an embodiment of the present invention.

Referring to FIG. 2, the camera 101 may be one of a plurality of cameras 1 to n (101a to 101n). The camera 101 can perform surveillance by switching between a first mode for monitoring an assigned area, a second mode for operating as a second camera, and a third mode for operating as a third camera. The camera 101 may include an image acquisition unit 201, a control unit 203, a storage unit 205, and a communication unit 207.

The image acquisition unit 201 may acquire an image by including an optical system, a photoelectric conversion unit, and an encoder. The optical system may include a lens that condenses the optical signal, an aperture that adjusts the amount (quantity of light) of the optical signal, and a shutter that controls the input of the optical signal. The photoelectric conversion unit receives optical signals input from the optical system and converts them into electrical image data. The photoelectric conversion unit may be an image sensor including an imaging device such as a charge coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS). The encoder can receive analog image data or digital image data from the photoelectric conversion unit depending on the characteristics of the imaging device. The encoder can convert analog video data into digital video data. The encoder may encode digital image data and output the encoded image data to the control unit 203.

The control unit 203 controls the overall operation of the camera 101 and performs functions such as exchanging control signals with the components to control the operation of each component or processing data. The control unit 203 may be implemented with a microchip or a circuit board including a microchip, and each component included in the control unit 203 may be implemented with software or circuits built into the control unit 203. . For example, the control unit 203 may include an application processor (AP), a microcontroller chip (MCU), etc.

The control unit 203 may include a detection unit 213, a tracking unit 233, a selection unit 253, and a setting unit 273.

The detection unit 213 may detect an event based on detection signals from a plurality of heterogeneous sensors that obtain detection information. For example, the detection unit 213 may detect an object by analyzing a detection signal from a PIR (Pyroelectric Infrared Ray) sensor, a motion detection sensor, or an image signal from the image acquisition unit 201 including an image sensor. there is. The detection unit 213 may detect a motion area through analysis of a plurality of image frames and determine it to be an object.

The tracking unit 233 may track the movement of the object using the analysis result of the detection unit 213. The tracking unit 233 may obtain tracking information of an object within an image (movie) by collecting information and/or detection signals about changes in the object between successive image frames. The tracking unit 233 can calculate the moving speed and direction of the object. Accordingly, the tracking unit 233 can predict the movement pattern and location of the object.

When the selection unit 253 receives an event signal according to object detection from the detection unit 213, it can select the second camera and the third camera.

The selection unit 253 may select the second camera according to the priority setting criteria for selecting the second camera set by the user. Priority setting criteria may include at least one of area importance and camera specifications. Area importance can be determined based on the frequency of occurrence of events in the area, the frequency of occurrence of dangerous situations, etc. For example, the area importance of an area with a high frequency of event occurrence and/or high risk situation occurrence may be relatively high.

In one embodiment, the selection unit 253 may first select cameras that can cover its area. The selection unit 253 may first select cameras assigned to an area adjacent to its own area. The selection unit 253 may compare the importance of its own area (hereinafter referred to as 'first area') with that of each of the first selected cameras. The selection unit 253 may select a camera assigned to an area with lower importance than the priority of the first area as the second candidate camera. The selection unit 253 may set a priority proportional to region importance for at least one second candidate camera. The selection unit 253 may not select the second camera if the area importance of the first area is the lowest.

In another embodiment, the selection unit 253 may first select cameras that can cover its area. The selection unit 253 may first select cameras assigned to an area adjacent to its own area. The selection unit 253 may use the first selected cameras as second candidate cameras. The selection unit 253 may compare its own camera specifications (hereinafter referred to as 'first camera specifications') with the camera specifications of the second candidate cameras. The selection unit 253 may set a priority proportional to the similarity to the first camera specifications for at least one second candidate camera. For example, if the first camera is a high-definition camera, the second camera may be selected as a camera that acquires images with similar image quality as the first camera.

In another embodiment, the selection unit 253 may initially select adjacent cameras that can cover its area. The selection unit 253 may first select cameras assigned to an area adjacent to its own area. The selection unit 253 may use the first selected cameras as second candidate cameras. The selection unit 253 may set the priority by considering both the area importance and camera specification similarity of the second candidate cameras. For example, the selection unit 253 may apply weights to the region importance and camera specification similarity of the second candidate cameras, respectively, and set a priority proportional to the weighted sum.

The selection unit 253 may broadcast a replacement request for surveillance of the first area to the second candidate cameras through the communication unit 207 and select the second camera according to the priorities of the second candidate cameras that responded within a predetermined time. there is. Alternatively, the selection unit 253 sequentially transmits a surveillance replacement request for the first area according to the priority set for the second candidate cameras through the communication unit 207, and selects the second candidate camera that responds within a predetermined time as the second camera. You can select .

The selection unit 253 may select the third camera according to the priority setting criteria for selecting the third camera set by the user. Priority setting criteria may include camera specifications. If it is predicted that the object leaves the first area based on the movement information of the object, the selection unit 253 may select at least one third camera candidate assigned to an area that can cover the predicted position of the object. The selection unit 253 may compare the first camera specifications and the camera specifications of the third candidate cameras. The selection unit 253 may set a priority proportional to the similarity to the first camera specifications for at least one third candidate camera. For example, if the first camera is a high-definition camera, the third camera may be selected as a camera that acquires images with similar image quality as the first camera.

The selection unit 253 may broadcast an object tracking request to third candidate cameras through the communication unit 207 and select the third camera according to the priorities of the third candidate cameras that responded within a predetermined time. Alternatively, the selection unit 253 may sequentially transmit object tracking requests to the third candidate cameras through the communication unit 207 according to the priorities set, and select the third candidate camera that responds within a predetermined time as the third camera. .

The selection unit 253 may simultaneously select two or more second cameras according to the terrain of the area or the surrounding environment and object characteristics. The selection unit 253 may simultaneously select two or more third cameras according to the terrain of the area or the surrounding environment and object characteristics.

The setting unit 273 can set a profile by adjusting the compression method (MJPEC, H.264, etc.), resolution, and frame rate within its camera specifications. The profile may be set by the user for each area and may be changed according to the characteristics of the detected object. Characteristics of an object may include the type of object (eg, person, vehicle, etc.), speed of the object, etc. When the camera 101 operates in the second mode and/or the third mode, the setting unit 273 may change the profile in response to the received profile change request. The setting unit 273 may request a profile change from the second camera and/or the third camera. For example, in the event of a car passing by, the setting unit 273 may request the third camera to increase the frame rate and resolution.

When the second camera and/or the third camera is selected and a request for surveillance replacement or object tracking is received, the control unit 203 may determine whether to accept or not and respond.

The storage unit 205 can store programs for processing and control of the control unit 203, and can temporarily store input or output data (for example, images, etc.). The storage unit 205 includes a flash memory type, hard disk type, multimedia card micro type, card type memory (for example, SD or XD memory, etc.), It may include at least one type of storage medium among RAM and ROM. Additionally, the storage unit 205 may be web storage that performs a storage function on the Internet.

The communication unit 207 may provide communication using wired communication and/or wireless communication links. The communication unit 207 may include a communication module capable of performing WiFi, 3G, LTE, and/or Radio Frequency (RF), and/or Bluetooth, or any suitable communication technology.

3A to 3C show an example explaining a monitoring method according to an embodiment of the present invention.

Referring to FIG. 3A, each of cameras 1 to 3 (101a to 101c) in the network is monitoring the set first to third areas (50a to 50c). The sizes of areas 50a to 50c may be the same or different depending on camera specifications or environments.

Referring to FIG. 3B, camera 1 (101a) can detect the object 400 and track the object 400 within the first area 50a. At this time, Camera 1 (101a) zooms in and tracks the object 400, thereby reducing the monitoring range to a partial area (50a') within the first area (50a). Camera 1 101a may select a second camera capable of covering the blind spot 50an in the first area 50a generated by tracking the object 400 based on area importance and camera specification similarity.

In FIG. 3B, camera 2 (101b), selected as the second camera, is switched to the second mode and covers the blind spot 50an of camera 1 (101a). Here, Camera 2 (101b) can monitor both its own area (50b) and the blind spot (50an) of Camera 1 (101a). Alternatively, camera 2 (101b) can monitor a portion of its own area (50b) and the blind spot (50an) of camera 1 (101a) within the maximum range that it can cover. The unmonitored area created by the area change of Camera 2 (101b) can be covered and monitored by Camera 3 (101c), which is selected as the second camera by Camera 2 (101b). Accordingly, Camera 2 (101b) and Camera 3 (101c) perform a zoom-out operation so that the areas 50b and 50c can be changed to areas 50b' and 50c', respectively. The size of the area monitored by the second camera may be the same or enlarged as the size of the originally allocated area.

Referring to FIG. 3C, when the object 400 leaves its area 50a, camera 1 (101a) can select a third camera to cover the predicted position of the object 400 based on camera specification similarity. .

In FIG. 3C, camera 2 (101b) is selected as the third camera and is tracking the object 400. In FIG. 3B, camera 2 (101b), which was monitoring the blind spot 50an of camera 1 (101a), is switched to the third mode and can track the object 400 following camera 1 (101a). At this time, Camera 2 (101b) zooms in and tracks the object 400, thereby changing the area to a partial area (50b") within the area (50b). Camera 1 (101a) returns to the originally assigned area (50a). Surveillance can be performed. The blind spot (50bn) caused by object tracking of camera 2 (101b) can be covered and monitored by camera 3 (101c), which is selected as the second camera. Accordingly, the Area 50c' may be changed to area 50c".

In FIGS. 3A to 3C , the first to third areas 50a to 50c are spaced apart from each other by a predetermined distance for convenience, but the first to third areas 50a to 50c may partially overlap.

Figure 4 is a diagram illustrating network construction of a surveillance system according to an embodiment of the present invention.

Referring to FIG. 4, a plurality of cameras 1 to n (101a to 101n) can form a first network (NW1), and a plurality of cameras 1 to k (101a to 101k) can form a second network (NW2). there is. The first network (NW1) and the second network (NW2) may each be a wired network or a wireless network.

When camera n (101n) of the first network (NW1) detects an object, it may not be possible to select the second camera and/or third camera within the first network (NW1) depending on the object's movement pattern and camera status. there is. In this case, camera n (101n) can acquire camera information about cameras 1 to k (101a to 101k) of the adjacent second network (NW2) directly or through the control device 530. Camera n (101n) may share camera information of cameras of the first network (NW1) and the second network (NW2) with cameras of the first network (NW1) and the second network (NW2). Accordingly, a third network that integrates the first network (NW1) and the second network (NW2) can be built. Accordingly, camera n (101n) can select the second camera and/or the third camera based on camera information of the third network.

The control device 530 may be connected to the first network (NW1) and the second network (NW2) by wire or wirelessly. The control device 530 can store and manage camera information of cameras of the first network (NW1) and the second network (NW2) in a table. The control device 530 may provide camera information of the second network (NW2) according to a request from camera n (101n) of the first network (NW1). The control device 530 may select the second camera and the third camera from among the cameras of the third network at the request of camera n (101n) or independently. Since the method of selecting the second camera and the third camera by the control device 530 is the same as the method of selecting the second camera and the third camera by the camera described above, description is omitted.

Figure 5 is a flowchart schematically explaining a monitoring method according to an embodiment of the present invention. The monitoring method of FIG. 5 can be performed by the above-described camera 101 or the control devices 130 and 530. Hereinafter, the monitoring method using the camera 101 will be described as an example. Detailed description of content that overlaps with the content described with reference to FIGS. 1 to 4 will be omitted.

Referring to FIG. 5, a first camera among a plurality of cameras in the current network (first network) may detect an object and track the detected object (S501). Each of the plurality of cameras can monitor a corresponding area divided from the surveillance area covered by the first network.

The first camera determines whether there are candidate cameras in the first network for a second camera to replace surveillance of an unmonitored area in its area resulting from object tracking and a third camera to replace object tracking following the first camera. It is possible to determine whether or not (S502). The first camera may select candidates for the second camera and the third camera based on area importance and/or camera specifications among the cameras.

If a candidate camera exists in the first network, the first camera may set a priority to at least one candidate camera (S503).

If there is no candidate camera in the first network, the first camera can build a new third network that integrates the first network and the second network by sharing camera information with cameras in the adjacent second network (S504 ). The new network may include all of the first network and the second network, or may include at least a portion of each of the first network and the second network.

The first camera can determine whether candidate cameras for the second camera and the third camera exist in the third network (S505).

If a candidate camera exists in the third network, the first camera can set a priority to at least one candidate camera (S503).

The first camera may select the second camera and the third camera from at least one candidate camera according to priority (S506).

In an embodiment of the present invention, cameras can be connected to build a network. Remote cameras can build a network by communicating with cameras in the middle as relay devices. The size of the network can be limited to a range that ensures the stability of peer-to-peer communication between cameras.

It is difficult for users to directly set connection information between cameras. In embodiments of the present invention, each camera operates like a wireless terminal and can configure its own network. Even if you do not use the same network, you can build a network by automating the registration of cameras that can be connected through independent communication with cameras from other certified networks. Through this process, each camera can manage its surveillance area, priority, connection information, etc. in a table.

In the above-described embodiment, the description was focused on the example of blind spots occurring due to object tracking, but the embodiments of the present invention can also be applied to cases where blind spots occur due to PTZ operation of a camera.

In the above-described embodiment, the description focuses on an example in which the first camera selects the second camera and the third camera. However, a candidate camera that has received a replacement request from the first camera may directly transmit the replacement request to another camera that can be replaced. This is possible because each camera manages the camera information of cameras in the network.

In an embodiment of the present invention, a unique ID is inserted into each replacement request for a camera to prevent the same replacement request from being transmitted repeatedly.

Embodiments of the present invention can be applied to areas where object tracking is required due to a high risk occurrence frequency, areas where traffic accidents occur frequently, and areas where PTZ cameras are installed.

The monitoring method according to an embodiment of the present invention can be implemented as computer-readable code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage devices. Additionally, computer-readable recording media can be distributed across computer systems connected to a network, so that computer-readable code can be stored and executed in a distributed manner. And, functional programs, codes, and code segments for implementing the present invention can be easily deduced by programmers in the technical field to which the present invention pertains.

One aspect of the present invention has been described with reference to the embodiments shown in the accompanying drawings, but these are merely illustrative, and various modifications and equivalent embodiments can be made by those skilled in the art. You will understand the point. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

Claims (5)

tracking the detected object by a first camera that has detected the object among a plurality of cameras monitoring each allocated area within the first network; and
First candidate cameras to which an area adjacent to the area allocated to the first camera is assigned are given priority based on the area importance of the areas allocated to each of the first candidate cameras and their similarity to the specifications of the first camera. Setting and selecting a second camera to replace surveillance of the area allocated to the first camera among the first candidate cameras according to the priorities set for the first candidate cameras,
The area importance is determined based on at least one of the frequency of occurrence of events and the frequency of occurrence of dangerous situations in the area,
A surveillance method wherein the area importance of the area allocated to the second camera is lower than the area importance of the area allocated to the first camera. According to paragraph 1,
A priority is set to second candidate cameras assigned to an area containing the predicted position of the object based on similarity to specifications of the first camera, and the second candidate cameras are assigned a priority according to the priorities set for the second candidate cameras. A surveillance method further comprising: selecting a third camera among two candidate cameras to perform tracking of the object. According to paragraph 2,
Requesting to change the profile of the third camera based on the characteristics of the object. According to paragraph 2,
Selecting the second camera among the first candidate cameras according to the priority of cameras that responded to the surveillance replacement request,
A surveillance method for selecting the third camera among the second candidate cameras according to the priority of cameras that responded to an object tracking request. According to paragraph 1,
If there is no candidate for the second camera among the cameras in the first network, establishing a third network with at least one of the cameras in a second network different from the first network.

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