KR20040065819A - Method for determining object motion in digital video recorder for monitoring - Google Patents

Abstract

PURPOSE: A method for deciding an object movement in a monitoring DVR(Digital Video Recorder) is provided to extract/compare features on previous/later frame video data picked up by a monitoring camera, and to decide whether an object moves, thereby exactly deciding an object movement. CONSTITUTION: A DVR performs a series of monitoring operations(S10). An A/D converter converts an analog video signal into digital frame video data(S11). An analyzer analyzes the digital frame video data, and temporarily stores feature information on the data(S12). If video data of a current frame is re-inputted, a comparator compares features of a previous frame and the current frame(S13). A motion decider decides whether the compared features are similar(S14). If not, the motion decider decides that an object moves between the frames(S15), and records the video data of the current frame(S16). A series of the same operations are repeated(S18).

Description

{Method for determining object motion in digital video recorder for monitoring}

The present invention relates to a method for determining the movement of a subject in a surveillance digital video recorder, and more particularly, to a surveillance digital video recorder for accurately determining and recording the movement of a subject photographed by a surveillance camera. It relates to a method for determining the movement of the subject.

Recently, a surveillance digital video recorder (DVR: Digital Video Recorder) capable of simultaneously monitoring various regions has been developed and commercialized. The surveillance digital video recorder (DVR) has a large amount of video or audio data. Storage such as a hard disk (HDD) capable of recording and storing, and a disc driver for recording and storing video or audio data on an optical disc such as a CD-RW, etc. It is provided.

Meanwhile, as shown in FIG. 1, the general surveillance digital video recorder (DVR) is connected to and connected to a plurality of surveillance cameras 10 ₁ to 10 _n respectively distributed in various regions requiring surveillance. In addition, it may be connected to various peripheral devices such as a plurality of monitoring sensors 20 ₁ to 20 _k .

In addition, the surveillance digital video recorder (DVR) may be connected to a personal computer 500 of a system operator located at a remote location through the network 400. For example, the surveillance digital video recorder (DVR) may be connected. ), The amount of change of the video signal photographed from the plurality of monitoring cameras is monitored, and when the amount of change of the video signal exceeds a preset reference change amount or a detection signal is received from the plurality of monitoring sensors, It is determined that an event such as a third party intrusion is detected.

When an event is detected through the above process, the video signal photographed from the surveillance camera installed in the corresponding area is recorded on the hard disk HDD as shown in FIG. 2.

When the video signal is recorded, the event is canceled, or the video signal recorded with the temporal continuity on the hard disk, that is, the recording size of the event detection video data exceeds 40 MBytes, for example. The detection video data is generated and managed as one data file. .

Accordingly, the system operator checks the surveillance video transmitted from the surveillance digital video recorder 300 in real time, or searches and confirms the data files recorded on the hard disk, so as to detect previously generated event situation and intruder. You can check again.

However, in the general surveillance digital video recorder 300, when the variation amount of the video image photographed from the surveillance camera exceeds the reference variation amount as described above, recording and storing the video image photographed from the surveillance camera in the hard disk. Therefore, when the illuminance of the place where the surveillance camera is installed or the ambient environment changes, it is impossible to accurately determine whether the subject is moving, and unnecessary video images are recorded and stored in the hard disk of limited recording capacity. There is a problem that the monitoring efficiency is lowered.

Accordingly, the present invention has been created to solve the above problems, and by extracting and comparing the characteristics of the frame video data before and after shooting from the surveillance camera, respectively, to determine whether the subject movement, Provides a method of determining the movement of a subject in a surveillance digital video recorder to more accurately determine whether the subject is being photographed by the surveillance camera even if the illuminance suddenly changes in the place where the camera is installed or the surrounding environment changes. There is a purpose.

1 is a view illustrating a state in which a general surveillance digital video recorder (DVR) is connected to a plurality of surveillance cameras, sensors, and personal computers of an operator.

2 schematically shows a data file recording process in a general surveillance digital video recorder,

3 illustrates a configuration of a surveillance digital video recorder to which a subject motion discrimination method according to the present invention is applied;

4 illustrates characteristics of frame video data extracted by a subject motion discrimination method according to the present invention;

5 is a flowchart illustrating an operation of determining a subject motion in a surveillance digital video recorder according to the present invention.

※ Explanation of code for main part of drawing

10 ₁ ~10 _n: camera for monitoring 20 ₁ ~20 _k: monitoring sensor

30: A / D converter 31: recording system

32: analyzer 33: buffer

34: comparator 35: motion discrimination unit

300: Surveillance Digital Video Recorder

400: network

500: personal computer

In accordance with an aspect of the present invention, there is provided a method of determining a subject motion in a digital video recorder for monitoring, after converting a frame video signal photographed from a surveillance camera into digital frame video data, and then, characteristics of the frame video data. Extracting and temporarily storing; Extracting and comparing the temporarily stored characteristic with the characteristic of the video data of the next frame and calculating a difference value between the characteristic; And determining whether or not the subject is photographed by the surveillance camera based on the calculated difference between the characteristics.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, a preferred embodiment of a method for determining a subject motion in a surveillance digital video recorder according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 3 shows a configuration of a surveillance digital video recorder to which a subject motion discrimination method according to the present invention is applied. The surveillance digital video recorder includes an A / D converter 30, a recording system 31, The analyzer 32, the buffer 33, the comparator 34, and the motion discriminator 35 may be included.

On the other hand, the A / D converter 30 performs A / D conversion on the analog frame video signal photographed from the surveillance camera and outputs the digital frame video data. In the recording system 31, the digital frame video is output. A series of recording operations for recording and storing data on a recording medium such as a hard disk (HDD) is performed. In the recording system 31, a control signal output from the motion discriminating unit 35, for example, The digital frame video data, which is converted and output by the A / D converter 30, is selectively recorded and stored on the basis of the control signal generated and output according to the determination that the subject movement is detected.

As shown in FIG. 4, the analyzer 32 analyzes the A / D-converted digital frame video data, and includes an edge component, an object shape, and a variance value of the corresponding frame. And a characteristic such as a histogram and the like are respectively detected and temporarily stored in the buffer 33.

In addition, the analyzer 32 analyzes the video data of the next frame A / D converted by the A / D converter 30, and has characteristics such as edge components, object shapes, and variance values and histograms of the frame. After the analysis is detected and temporarily stored in the buffer 33, the characteristics of the previous frame previously stored and the characteristics of the currently analyzed frame are output to the comparator 34, respectively.

In the comparator 34, the characteristics of the previous frame, that is, the edge component, the object shape, and the variance value and histogram, which are respectively output through the above process, the edge component of the current frame, the object shape, and the variance value, The histograms are compared to each other and the difference value is calculated.

In addition, the motion discrimination unit 35 compares and confirms whether a difference value between the characteristics compared and calculated by the comparator 34 exceeds a preset threshold value, for example, allowing When the reference value is exceeded, it is determined that a subject movement has occurred between the previous frame and the current frame, and then a corresponding control signal is output to the recording system 31 so that the video data of the current frame is recorded and stored on the hard disk. do.

On the other hand, when the difference value between the characteristics of the previous frame and the characteristics of the current frame does not exceed the allowable reference value, a corresponding control signal is output to the recording system 31, so that the video data of the current frame, It does not record and store in the hard disk, which will be described in detail below.

FIG. 5 is a flowchart illustrating a method of determining a subject motion in a surveillance digital video recorder according to the present invention. In the surveillance digital video recorder 300, images are captured from surveillance cameras distributed in a surveillance area. A series of surveillance operations for monitoring the video image is performed (S10), wherein the analog video signal photographed from the surveillance camera is converted into digital frame video data by the A / D converter 30 ( S11).

The digital frame video data is temporarily stored in the recording system 31 and input to the analyzer 32. In the analyzer, an edge component and an object shape of the digital frame video data are input. In addition, after analyzing and detecting the variance value and the histogram as the characteristics of the corresponding frame, the characteristic information is temporarily stored in the buffer 33 (S12).

Subsequently, when the video data of the current frame photographed by the surveillance camera and A / D converted is inputted to the analyzer 32 again, the edge component, the subject shape, and the dispersion value for the video data of the current frame. And after analyzing and detecting a histogram as a characteristic of the current frame, the operation of temporarily storing the histogram in the buffer 33 is repeated. In the comparator 34, the previous frame analyzed and detected through the above process, respectively The characteristics of and the characteristics of the current frame are compared with each other (S13).

On the other hand, in the comparison process, the difference value between each characteristic is calculated and output to the motion discriminating unit 35, the motion discriminating unit 35 determines whether the characteristics are similar to each other (S14), for example For example, when the difference values between the calculated characteristics exceed a preset allowable reference value, it is determined that a subject movement has occurred between the previous frame and the current frame (S15), and the recording system 31 By controlling the operation, video data of the current frame in which the motion is detected is recorded and stored in the hard disk (S16).

On the other hand, when the difference value between the characteristics of the previous frame and the characteristics of the current frame does not exceed an allowable reference value, that is, when the characteristics are similar to each other, it is determined that no subject movement occurs between the previous frame and the current frame. In operation S17, the video data of the current frame is not recorded and stored on the hard disk. Then, the above series of operations are repeatedly performed until the surveillance system operation is terminated (S18).

Therefore, only the video data from which the movement of the subject is determined can be selectively recorded on the hard disk. The analyzer, the comparator, and the motion discrimination unit may be included in one software or may be included in separate hardware. The analyzer may extract and analyze other values other than edge components, object shapes, variance values, and histograms as characteristics of the frame video data.

Or more, preferred embodiments of the present invention described above, for the purpose of illustration, those skilled in the art, within the technical spirit and the technical scope of the present invention disclosed in the appended claims below, to further improve various other embodiments Changes, substitutions or additions will be possible.

The object motion discrimination method of the surveillance digital video recorder according to the present invention constructed and constructed as described above comprises converting a frame video signal photographed from a surveillance camera into digital frame video data, and then an edge component of the frame video data. At least one component of a subject shape, a dispersion value, and a histogram is extracted and temporarily stored as a characteristic of the frame video data, and then captured by a surveillance camera in comparison with the characteristics of the frame video data captured and extracted later. By determining whether or not the subject moves, the illuminance may suddenly change in the place where the surveillance camera is installed, or even when the surrounding environment changes, thereby accurately determining whether the subject photographed by the surveillance camera moves or not. Very useful feet that can be improved It is a person.

Claims (5)

Converting the frame video signal photographed from the surveillance camera into digital frame video data, and then extracting and temporarily storing characteristics of the frame video data; Extracting and comparing the temporarily stored characteristic with the characteristic of the video data of the next frame and calculating a difference value between the characteristic; And And determining the movement of the subject photographed by the surveillance camera on the basis of the calculated difference between the characteristics. 3. The method of claim 1, In the first step, at least one of an edge component, a subject shape, a dispersion value, and a histogram of the frame video data is extracted and temporarily stored as a characteristic of the frame video data. How to determine the movement of the subject. The method of claim 1, In the second step, the difference between the characteristics is calculated by extracting and comparing at least one of an edge component, a subject shape, a variance value, and a histogram with respect to the video data of the next frame. A subject motion discrimination method in a surveillance digital video recorder, characterized in that the. The method of claim 1, In the third step, when the difference value between the calculated characteristics exceeds a preset reference value, the surveillance digital video recorder, characterized in that it is determined that the movement of the subject photographed by the surveillance camera has been detected. How to determine the movement of the subject. The method of claim 1, And if it is determined that the movement of the subject photographed by the surveillance camera is detected, recording and storing the video data of the corresponding frame in the apparatus.