KR20110048786A - Method for detecting disturbance of monitoring camera, and monitoring camera using the same - Google Patents

Abstract

PURPOSE: A control method of a monitoring camera is provided to determine contamination of transparent cover through a standard deviation of focus values form an image data of a transparent cover. CONSTITUTION: A microcomputer receives a focus value while proceeding panning of an optical system(S804). The focus values is obtained form an image data of a transparent cover. The microcomputer calculates a mean value of all inputted focus values(S809). The microcomputer calculates a standard deviation of all focus values about a mean value(S811). If the standard deviation is larger than a maximum deviation, the microcomputer transmits contamination of a transparent cover(S812, S813).

Description

Method for detecting disturbance of monitoring camera, and monitoring camera using the same}

The present invention relates to a method for controlling a surveillance camera and a surveillance camera using the same, and more particularly, to generate a live-view video signal by shooting in a state where a transparent cover is covered in front of an optical system. A control method of a camera and a surveillance camera using the same.

Surveillance cameras generate live-view video signals by imaging. Surveillance cameras also transmit live-view video signals to the computers while communicating with the computers as monitoring devices.

In such surveillance cameras, a transparent cover is covered to protect the optical system.

However, there is no control method in which the control unit inside the surveillance camera determines whether the transparent cover is contaminated.

Accordingly, even if the user cleans the transparent cover regularly, there is a problem that the monitoring function is degraded when the transparent cover is quickly contaminated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method of a surveillance camera and a surveillance camera using the same, in which a transparent cover is quickly polluted so that the surveillance function is not deteriorated.

The method of the present invention is a control method of a surveillance camera which generates a live-view video signal by photographing in a state where a transparent cover is covered in front of an optical system, comprising steps (a) to (d). do.

In the step (a), the focus values obtained from the image data of each part of the transparent cover are input while panning to rotate the optical system to the left and right.

In step (b), the average value of all input focus values is calculated.

In step (c), the standard deviation of all the focus values with respect to the average value is calculated.

In step (d), it is known that the transparent cover is contaminated if the standard deviation is greater than the upper limit deviation.

The surveillance camera of the present invention includes a control unit and generates a live-view video signal by photographing in a state where a transparent cover is covered in front of the optical system. Here, the control method used in the control unit includes the steps (a) to (d).

According to the control method of the surveillance camera of the present invention and the surveillance camera using the same, it is possible to determine whether the transparent cover is contaminated using the standard deviation of the focus values obtained from the image data of each part of the transparent cover.

This is because the standard deviation of the focus values when the transparent cover is contaminated is larger than when it is not.

Therefore, the controller inside the surveillance camera may detect and notify the user when the transparent cover is quickly polluted.

Therefore, even if the transparent cover is quickly contaminated, the user may know this, so that the monitoring function may not be degraded by the user cleaning the transparent cover when necessary.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a surveillance system to which surveillance cameras 1a, 1b and 1c are applied according to a first embodiment of the present invention.

Referring to FIG. 1, each of the surveillance cameras 1a, 1b and 1c generates a live-view video signal by photographing.

In addition, each of the surveillance cameras 1a, 1b, 1c communicates with the computers 3a, 3b, 3c as monitoring devices via a communication channel D _COM , and is live- _viewed through the video signal channel S _VID . The video signal of the (Live-view) is transmitted to the computers 3a, 3b, and 3c.

FIG. 2 shows the appearance of any of the surveillance cameras 1a, 1b, 1c of FIG. 1.

Referring to FIG. 2, the surveillance cameras 1a, 1b and 1c of FIG. 1 are covered with a transparent cover 22 in front of the optical system OPS to protect the optical system OPS of the body 21 and maintain cleanliness. have.

1 and 2, each of the surveillance cameras 1a, 1b, 1c according to the first embodiment of the present invention, periodically or according to a user command from one of the computers 3a, 3b, 3c, While performing panning to rotate the optical system OPS to the left and right, focus values obtained from image data of each part of the transparent cover 22 are obtained, and if the standard deviation of these focus values is greater than the upper limit deviation, the transparent cover 22 Notifies the computers 3a, 3b, and 3c that the computer has been contaminated.

This is because the standard deviation of the focus values when the transparent cover 22 is contaminated is larger than otherwise. Hereinafter, each of the focus values means an average value of gray level difference values of adjacent pixels.

Therefore, the control unit inside the surveillance cameras 1a, 1b, and 1c may detect and notify the user when the transparent cover 22 is quickly polluted.

Therefore, even if the transparent cover 22 is quickly contaminated, since the user can know this, the monitoring function may not be degraded by the user cleaning the transparent cover 22 when necessary. Related contents will be described in detail with reference to FIGS. 3 to 8.

FIG. 3 shows the internal configuration of the body 21 of either surveillance camera 1a or 1b or 1c of FIG. 2.

Referring to FIG. 3, the surveillance camera 1a or 1b or 1c according to the present invention may include an optical system (OPS), a photoelectric converter (OEC), a CDS-ADC (Correlation Double Sampler and Analog-to-Digital Converter, 301), Timing circuit 302, Digital Signal Processor (DSP) as a control unit, Digital Signal Processor (307), Video-Signal Generator (308), Aperture Motor (M _A ), Zoom Motor (M _Z ), Focus Motor (M _F ) , Filter motor M _D , panning motor M _P , tilting motor M _T , driver 310, communication interface 112, micro-computer 313, and lighting unit 315.

The optical system OPS including the lens unit and the filter unit optically processes light from a subject.

The lens unit of the optical system OPS includes a zoom lens and a focus lens. In the filter unit of the optical system OPS, an optical low pass filter (OLPF) used in a night mode of operation removes optical noise having a high frequency content. Infra-Red cut filter (IRF) used in daytime operation mode cuts off the infrared component of incident light.

A photoelectric conversion unit (OEC) of a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) converts light from an optical system (OPS) into an electrical analog signal. Here, the digital signal processor 307 controls the timing circuit 302 to control the operation of the photoelectric converter OEC and the Correlation Double Sampler and Analog-to-Digital Converter (301).

The CDS-ADC 101 processes the analog video signal from the photoelectric converter (OEC), removes the high frequency noise, adjusts the amplitude, and converts the digital video data. This digital image data is input to the digital signal processor 307.

The digital signal processor 307 processes the digital signal from the CDS-ADC element 101 to generate digital image data classified into luminance and chroma signals.

The video-signal generator 308 converts the digital image data from the digital signal processor 307 into a video signal S _VID which is an analog image signal.

The digital signal processor 307 communicates with the digital video recorder (DVR, 2 of FIG. 1) as a recording device via the communication interface 312 and the communication channel (D _{COM in} FIG. 1), and the video signal channel S _VID . The video signal S _VID from the video-signal generator 308 is transmitted to the computers 3a, 3b, and 3c.

Meanwhile, the micro-computer 313 controls the driving unit 310 to control the aperture motor M _A , the zoom motor M _Z , the focus motor M _F , the filter motor M _D , and the panning motor M _P. And a tilting motor (M _T ).

The aperture motor M _A drives the aperture, the zoom motor M _Z drives the zoom lens, and the focus motor M _F drives the focus lens. The filter motor M _D drives the optical low pass filter OLPF and the infrared cut filter IRF at the filter part.

The panning motor M _P rotates the optical system OPS from side to side. The tilting motor M _T rotates the optical system OPS up and down.

Here, the micro-computer 313 periodically or in accordance with the user command input from the computer 3a, 3b, 3c through the communication interface 312 and the digital signal processor 307, Focus obtained from the image data of each part of the transparent cover (22 in FIG. 2) while controlling to perform panning for rotating the optical system OPS to the left and right and tilting for rotating the optical system OPS up and down. Values are received from the digital signal processor 307.

For such panning and tilting, the micro-computer 313 controls the driving unit 310 to move the zoom lens in the optical system OPS so as to be in the maximum wide angle state. In addition, the micro-computer 313 controls the driving unit 310 to move the focus lens to the position of the focus lens corresponding to the position of the transparent cover 22, that is, the designated focusing position.

In addition, the micro-computer 313 indicates that the transparent cover 22 is contaminated when the standard deviation of the focus values is larger than the upper limit deviation. 3c).

This is because the standard deviation of the focus values when the transparent cover 22 is contaminated is larger than otherwise. As described above, each of the focus values means an average value of gray level difference values of adjacent pixels.

Thus, the micro-computer 313 inside the surveillance cameras 1a, 1b, 1c can detect and notify the user when the transparent cover 22 is quickly contaminated.

Therefore, even if the transparent cover 22 is quickly contaminated, the user may know this, so that the monitoring function may not be degraded by the user cleaning the transparent cover 22 when necessary.

Here, when the average value of each of the focus values is less than the reference value, the micro-computer 313 controls the lighting unit 315 to illuminate the illumination light on the transparent cover 22. Accordingly, it is possible to accurately determine whether the transparent cover 22 is contaminated even in a dark environment.

4 illustrates the focus values of the transparent cover 22 input by the panning angle from the digital signal processor 307 of FIG. 3 when the transparent cover 22 of FIG. 2 is contaminated.

FIG. 5 illustrates focus values of the transparent cover 22 input by the panning angle from the digital signal processor 307 of FIG. 3 when the transparent cover 22 of FIG. 2 is not contaminated.

FIG. 6 shows a scatter plot corresponding to the standard deviation of the graph of FIG. 4.

FIG. 7 shows a scatter plot corresponding to the standard deviation of the graph of FIG. 5.

4 to 7, the average value M _AVS of the focus values when the transparent cover 22 is contaminated is larger than the average value F _AVR . In addition, it can be seen that the standard deviation of the average value F _AVS of the focus values when the transparent cover 22 is contaminated is larger than that otherwise.

FIG. 8 shows a cover-contamination detection algorithm of the micro-computer 313 as the controller of FIG. 3. This algorithm is performed periodically or according to a user command input from a computer (3a, 3b, 3c in FIG. 1) through a communication interface (312 in FIG. 3) and a digital signal processor (307 in FIG. 3).

Referring to FIGS. 3 to 8, the cover-contamination detection algorithm of FIG. 8 will be described.

First, the micro-computer 313 controls the driving unit 310 to move the zoom lens in the optical system to the maximum wide angle state (step S801).

Next, the micro-computer 313 controls the driving unit 310 to move the focus lens to the position of the focus lens corresponding to the position of the transparent cover (22 in FIG. 2), that is, the designated focusing point position (step S802).

Next, the micro-computer 313 controls the driving unit 310 to drive the tilting motor M _T such that the tilting angle of the optical system OPS becomes 0 ^o (step S803).

Next, the micro-computer 313 receives the focus values of the transparent cover 22 of FIG. 2 from the digital signal processor 307 while performing the panning by controlling the driver 310 (step S804).

Next, the micro-computer 313 controls the driving unit 310 to drive the tilting motor M _T such that the tilting angle of the optical system OPS is 30 ^° (step S805).

Next, the micro-computer 313 receives the focus values of the transparent cover 22 of FIG. 2 from the digital signal processor 307 while performing the panning by controlling the driver 310 (step S806).

Next, the micro-computer 313 controls the driving unit 310 to drive the tilting motor M _T such that the tilting angle of the optical system OPS is 60 ^° (step S807).

Next, the micro-computer 313 receives the focus values of the transparent cover 22 of FIG. 2 from the digital signal processor 307 while performing the panning by controlling the driver 310 (step S808).

Next, the micro-computer 313 calculates an average value F _AVS or F _AVR of all input focus values (step S809).

Next, the micro-computer 313 determines whether the average value F _AVS or F _AVR of all the focus values is less than the reference value F _LMA (step S810).

If the average value (F _AVS or F _AVR ) of all the focus values is less than the reference value (F _LMA ), the accuracy of the input data may be regarded as inferior, so that the micro-computer 313 controls the lighting unit 315. After illuminating the transparent cover 22 with the illumination light (step S815), the steps S803 to S810 are performed again. Accordingly, it is possible to accurately determine whether the transparent cover 22 is contaminated even in a dark environment.

If the average value F _AVS or F _AVR of all the focus values is not less than the reference value F _LMA , the micro-computer 313 determines the standard deviation of the average value F _AVS or F _AVR of all the input focus values. Is calculated (step S811).

The micro-computer 313 then passes through the digital signal processor 307 and the communication interface 312 that the transparent cover 22 is contaminated if the standard deviation F _DES of the focus values is greater than the upper limit deviation F _HMD . The computer 3a, 3b, 3c is informed (steps S812 and S813).

In addition, the micro-computer 313 indicates that the transparent cover 22 is not contaminated unless the standard deviation F _DES of the focus values is greater than the upper limit deviation F _HMD , and the digital signal processor 307 and the communication interface 312. The computer 3a, 3b, and 3c are informed via () (steps S812 and S814).

As described above, according to the control method of the surveillance camera according to the present invention and the surveillance camera using the same, it is possible to determine whether the transparent cover is contaminated using the standard deviation of the focus values obtained from the image data of each part of the transparent cover. have.

This is because the standard deviation of the focus values when the transparent cover is contaminated is larger than when it is not.

Therefore, the controller inside the surveillance camera may detect and notify the user when the transparent cover is quickly polluted.

Therefore, even if the transparent cover is quickly contaminated, the user may know this, so that the monitoring function may not be degraded by the user cleaning the transparent cover when necessary.

It can be used not only for surveillance cameras but also for all cameras capable of shooting video.

1 is a block diagram illustrating a surveillance system to which surveillance cameras according to a first exemplary embodiment of the present invention are applied.

FIG. 2 is a diagram illustrating an external appearance of the surveillance camera of FIG. 1.

3 is a block diagram illustrating an internal configuration of the surveillance camera of FIG. 2.

FIG. 4 is a graph showing focus values input for each panning angle from the digital signal processor of FIG. 3 when the transparent cover of FIG. 2 is contaminated.

5 is a graph showing focus values input for each panning angle from the digital signal processor of FIG. 3 when the transparent cover of FIG. 2 is not contaminated.

FIG. 6 is a graph showing a scatter plot corresponding to the standard deviation of the graph of FIG. 4.

FIG. 7 is a graph showing a scatter plot corresponding to the standard deviation of the graph of FIG. 5.

8 is a flowchart showing a cover-contamination detection algorithm of the micro-computer as the control unit of FIG.

<Explanation of symbols for the main parts of the drawings>

1a, 1b, 1c ... surveillance cameras, 3a, 3b, 3c ... computers,

21 body, 22 transparent cover,

OPS ... optical system, OEC ... photoelectric conversion unit,

301 ... CDS-ADC, 302 ... timing circuit,

307 digital signal processor, 308 video signal generator,

310 drive section, 312 communication interface,

313 micro-computer, 315 lighting unit.

Claims (10)

A control method of a surveillance camera that generates a live-view video signal by shooting in a state where a transparent cover is covered in front of an optical system, (a) receiving focus values obtained from image data of each part of the transparent cover while panning the optical system to rotate left and right; (b) calculating an average value of all input focus values; (c) calculating a standard deviation of all the focus values relative to the mean value; And and (d) informing that the transparent cover is contaminated when the standard deviation is greater than the upper limit deviation. The method of claim 1, wherein in step (a), And each of the focus values is an average value of gray level difference values of adjacent pixels. The method of claim 1, wherein in step (a), And the panning is performed along with tilting of rotating the optical system up and down. The method of claim 1, If the average value calculated in the step (b) is less than the lower limit value, illumination light is shining on the transparent cover. A control method of a surveillance camera that generates a live-view video signal by shooting in a state where a transparent cover is covered in front of an optical system, (a) moving the zoom lens in the optical system to obtain a maximum wide angle state; (b) moving the focus lens to the position of the focus lens corresponding to the position of the transparent cover; (c) receiving focus values while performing panning to rotate the optical system from side to side; (d) calculating an average value of all input focus values; (e) calculating a standard deviation of all the focus values relative to the average value; And (f) controlling the surveillance camera including a notification that the transparent cover is contaminated when the standard deviation is greater than the upper limit deviation. The method of claim 5, wherein in step (c), And each of the focus values is an average value of gray level difference values of adjacent pixels. The method of claim 5, wherein in step (c), And the panning is performed along with tilting of rotating the optical system up and down. The method of claim 5, And if the average value calculated in the step (d) is less than the lower limit value, illumination light is shined on the transparent cover. A surveillance camera comprising a control unit, wherein the surveillance camera generates a live-view video signal by capturing a transparent cover in front of an optical system. The control method used in the control unit, (a) receiving focus values obtained from image data of each part of the transparent cover while panning the optical system to rotate left and right; (b) calculating an average value of all input focus values; (c) calculating a standard deviation of all the focus values relative to the mean value; And (d) a surveillance camera comprising a notification that the transparent cover is contaminated if the standard deviation is greater than the upper limit deviation. A surveillance camera comprising a control unit, wherein the surveillance camera generates a live-view video signal by capturing a transparent cover in front of an optical system. The control method used in the control unit, (a) moving the zoom lens in the optical system to obtain a maximum wide angle state; (b) moving the focus lens to the position of the focus lens corresponding to the position of the transparent cover; (c) receiving focus values while performing panning to rotate the optical system from side to side; (d) calculating an average value of all input focus values; (e) calculating a standard deviation of all the focus values relative to the average value; And (f) a surveillance camera comprising a notification that the transparent cover is contaminated if the standard deviation is greater than the upper limit deviation.

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