JP2012013567A - Wave overtopping detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wave overtopping detection system having less erroneous detection and high reliability.SOLUTION: The wave overtopping detection system includes: a monitoring camera by which an area for monitoring the wave overtopping is imaged to output imaged data; an antenna which radiates radio waves toward the waves moving forward and backward toward and from a breakwater, and receives reflection waves reflected by a reflector and returned thereto; and a remote control monitoring device which determines whether or not motion exceeding the breakwater exists by analyzing the image data outputted from the monitoring camera, and also determines that the wave overtopping occurs when it is determined that the motion exists and then when Doppler velocity obtained from the frequency spectrum of the reflection waves satisfies prescribed conditions.

Description

  The present invention relates to an overtopping detection system for detecting overtopping flowing into a bank beyond the top of a seawall or breakwater.

  A conventional overtopping detection device includes an imaging unit that captures an image of an area where overtopping is monitored, a control unit that controls the imaging unit, a frame memory that stores image data from the imaging unit, and a rippling from the image data. A wave contour shape extraction unit that extracts a wave contour shape, and an overtopping determination unit that determines the occurrence of overtopping based on a change in the wave contour shape extracted by the wave contour shape extraction unit (see, for example, Patent Document 1) ).

JP 2006-52974 A

  However, with such overtopping detection devices, it is falsely detected that other moving factors (moving objects such as cars, people, and bicycles, their shadows, car lights, etc.) enter the monitoring area. There was a problem to do.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain an overtopping detection system with few false detections and high reliability.

  The overtopping detection system according to the present invention includes a surveillance camera that captures an area where overtopping is monitored and outputs image data, and radiates a radio wave toward a wave moving forward and backward toward the breakwater and is reflected back by a reflector. From the antenna that receives the reflected wave and the image data output from the monitoring camera to determine whether there is movement over the breakwater and when it is determined that there is movement, from the frequency spectrum of the reflected wave A remote control monitoring device that determines that overtopping occurs when the obtained Doppler speed satisfies a predetermined condition.

  In the overtopping detection system according to the present invention, when it is determined that there is movement in the monitoring area by analyzing the image data, it is further determined that overtopping has occurred using the Doppler velocity data. Even if a factor with other motion enters, the Doppler velocity at that time is different from the Doppler velocity when the radio wave is reflected by the wave, and it is possible to prevent other factors with motion from being erroneously determined as overtopping.

1 is a configuration diagram of an overtopping detection system according to a preferred embodiment of the present invention. It is a figure which shows a mode that the overtopping detection system of FIG. 1 has been arrange | positioned in the breakwater vicinity.

Hereinafter, preferred embodiments of the overtopping detection system of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an overtopping detection system according to a preferred embodiment of the present invention. FIG. 2 is a diagram illustrating a state where the overtopping detection system of FIG. 1 is arranged in the vicinity of the breakwater.
The overtopping detection system according to Embodiment 1 of the present invention is a system that detects overtopping that flows into the road 32 beyond the top of the breakwater 31, and is a surveillance camera that captures a monitoring area including the top of the breakwater 31. 1, an antenna 11 that radiates radio waves in a direction toward a wave approaching the breakwater 31, receives radio waves reflected by the waves and converts them into high-frequency signals, and temporarily stores data of images taken by the monitoring camera 1. In addition, the IP video server 2 that sends image data to the Web server according to the request from the Web browser, the antenna drive device 12 that drives the antenna 11, and the high frequency signal that is transmitted to the antenna 11 and received by the antenna 11 The transmission / reception device 13 that receives the signal, the high frequency signal that is transmitted, and the high frequency signal that is received And a signal processing unit 14 for extracting a la speed.

In addition, the overtopping detection system according to Embodiment 1 of the present invention transmits a Doppler velocity data to the transmission device 3 and receives control data for controlling the antenna driving device 12 and the transmission / reception device 13 from the transmission device 3. And a transmission device 3 for transmitting image data and Doppler speed data to the Internet 4 and receiving control data for controlling the antenna 11 and the transmission / reception device 13 via the Internet 4.
The IP video server 2, the transmission device 3, the antenna driving device 12, the transmission / reception device 13, the signal processing device 14, and the control monitoring device 15 are collectively referred to as a transmission / reception signal processing unit 100, and the IP video server 2, the transmission device 3, and the antenna. The drive device 12, the signal processing device 14, and the control monitoring device 15 are configured from a computer.

The overtopping detection system according to the first embodiment of the present invention receives the image and Doppler speed data via the Internet 4 and transmits the control data for the antenna 11 and the transmission / reception device 13. A Web display device 22 for displaying, a recording device 23 for recording image data, a control device 24 for outputting control data of the antenna 11 and the transmission / reception device 13 and a remote control monitoring device 24 for detecting overtopping from image data and Doppler velocity data. .
The transmission device 21, the Web display device 22, the recording device 23, and the remote control monitoring device 24 are collectively referred to as a remote control monitoring unit 101, and are configured from a computer.

The surveillance camera 1 captures a surveillance area including the top of the breakwater 31 and transmits it to the IP video server 2 for each frame at a predetermined cycle.
The IP video server 2 accumulates the image data transmitted from the surveillance camera 1 with the shooting date and time as metadata. In addition, the IP video server 2 transmits image data to the Web browser in accordance with a request from the Web browser of the remote control monitoring device 24.
The turntable 18 of the antenna 11 rotates the antenna 11 in the biaxial direction by a control signal from the antenna driving device 12, and the radio wave radiated from the antenna 11 is shaken in the horizontal direction and the vertical direction.
The turntable 18 of the antenna 11 is rotated or stopped by a control signal sent from the remote control monitoring device 24.

When the wave is likely to cross the breakwater 31, the radio wave radiated from the antenna 11 is reflected by the rising wave, and the reflected wave returned to the antenna 11 has a higher frequency due to the Doppler effect. Therefore, the signal processing device 14 obtains the frequency spectrum of the high-frequency signal received by the receiving unit 16 of the transmitting / receiving device 13 and obtains the peak value and the half value width. The difference between the peak value and the frequency of the high-frequency signal output from the transmitter 17 is obtained, and the Doppler velocity is detected from the obtained difference.
Further, the Doppler velocity obtained from the high-frequency signal received by the receiving unit 16 depends on the wave velocity, and the half width depends on the wave amount. When rain is blowing at the same time as the waves, the waves and rain can be separated by a half-value width.
The signal processing device 14 obtains the Doppler velocity and the half width, and sends the Doppler velocity data to the control monitoring device 15 as Doppler velocity data. At that time, the detection date as metadata is attached to the Doppler speed data and sent.

  The remote control monitoring device 24 analyzes the image data and determines whether or not there is a movement in the monitoring area. That is, several monitoring areas are set in the image in advance, and the movement in the monitoring area is detected. The motion detection method calculates the average of the relative density difference by dividing the sum of the relative density differences representing the difference between the two image signals obtained by imaging before and after the time by the total number of pixels in the measurement range. If the value is exceeded, it is determined that there is movement. The limit value is obtained by multiplying the average value obtained by dividing the total of the average M (i) of N density relative differences obtained successively in succession by a correction coefficient k (k> 1). Furthermore, a trigger signal is generated when the average of the density relative difference exceeds the limit value. When this trigger signal is generated, the average of the density relative difference is compared with the limit value over a predetermined number of times, It is determined that there is a motion when the number of times exceeding the limit value is equal to or greater than a predetermined number.

When the remote control monitoring device 24 analyzes the image data and determines that there is movement in the monitoring area, whether or not overtopping has occurred using Doppler velocity data having the same detection date and time as the shooting date and time of the image. Determine whether.
An average value of the Doppler speed is extracted from the Doppler speed data, and it is determined that overtopping has occurred when the average value is larger than a predetermined threshold.

  When it is determined that there is movement in the monitoring area by analyzing the image data in this way, it is further determined that overtopping has occurred using the Doppler velocity data, so there is other movement in the monitoring area. Even if a factor is entered, the Doppler velocity at that time is different from the Doppler velocity when the radio wave is reflected by a wave, and it is possible to prevent other factors having movements from being erroneously determined as overtopping.

  DESCRIPTION OF SYMBOLS 1 Surveillance camera, 2 IP video server, 3 Transmission apparatus, 4 Internet, 11 Antenna, 12 Antenna drive apparatus, 13 Transmission / reception apparatus, 14 Signal processing apparatus, 15 Control monitoring apparatus, 16 Reception part, 17 Transmission part, 18 Turntable, 21 transmission device, 22 Web display device, 23 recording device, 24 remote control monitoring device, 31 breakwater, 32 road, 100 transmission / reception signal processing unit, 101 remote control monitoring unit.

Claims (3)

A surveillance camera that captures the area where overtopping is monitored and outputs image data;
An antenna that radiates radio waves toward a wave moving forward and backward toward the breakwater and receives a reflected wave that is reflected back by a reflector;
The image data output from the surveillance camera is analyzed to determine whether or not there is movement over the breakwater, and when it is determined that there is movement, the Doppler velocity obtained from the frequency spectrum of the reflected wave satisfies a predetermined condition A remote control monitoring device that determines that time overtopping will occur,
A wave overtopping detection system comprising:   2. The overtopping detection system according to claim 1, wherein the remote control monitoring device separates the wave and the rain according to the peak width of the spectrum of the reflected wave. A web display device for displaying image data output from the surveillance camera;
The overtopping detection system according to claim 1, wherein the remote control monitoring device controls the monitoring camera and an antenna.

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