JP2001356015A - Wave measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave measuring system capable of surely extracting waves information by obtaining a relative water level of a side part of a floating body by analyzing an image photographed by one video camera on the body and further correcting the relative water level. SOLUTION: The wave measuring system images a crossing line 3 of a side face 1a of the floating body 1 and a wave motion 2 by the video camera 4, analyzes the image by an image processor 5 to obtain a relative water level, corrects the water level based on response characteristics of the waves of the floating body 1, extracts wave information including an incident wave direction spectrum of the wafer to the body 1, an angle of wave encounter, a significant wave height and a significant period, and displays the information on a display unit 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wave measuring system provided on a floating body such as a ship.

[0002]

2. Description of the Related Art Conventionally, a wave measuring device mounted on a ship includes a device using a laser beam, a device using an ultrasonic wave, and a device using a radio wave, and many devices include a plurality of sensors. Each of these sensors emits various signals toward the sea surface from each sensor, and operates to acquire wave information from signals reflected and returned from the sea surface. In addition, the wave measurement from the floating body includes a buoy. Wave measurement buoys are equipped with accelerometers that measure vertical movement, as well as measuring devices for the inclination angle of the floating body and the flow velocity acting on the floating body, and acquire wave information by integrating information obtained from these measuring devices. is there. As a wave measuring device using a video camera, a technology has been developed which is configured using two cameras and operates to calculate the position of a specific point on the sea surface in three dimensions.

[0003] Among the conventional wave measuring devices, those mounted on a ship use artificial signals such as ultrasonic waves, laser beams, and radio waves as described above. Since information is obtained from the reflected signal, the measurement accuracy is significantly dependent on the sea surface condition. In addition, the buoy shape of the buoy must be designed so as to be suitable for wave measurement. In the case of using a video camera, it is necessary to set a common point on the sea surface in images obtained from the two cameras in order to measure a three-dimensional position using two video cameras. In some cases, it is expected that measurement will be difficult.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention determines the relative water level at the side of the floating body by analyzing an image taken by using at least one video camera on the floating body, It is an object of the present invention to provide a wave measurement system capable of accurately extracting wave information by correcting the relative water level based on response characteristics.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a wave measuring system according to the present invention comprises: With the image analysis means for analyzing the image of the intersection line taken by the video camera to determine the relative water level of the side of the floating body, the relative water level determined by the image analysis means of the floating body Wave information extracting means for extracting wave information including a wave incident spectrum, a meeting angle, a significant wave height and a significant period of the wave with respect to the floating body by correcting based on a response characteristic to the wave. I have.

The wave measuring system according to the present invention is characterized in that the floating body is configured as a ship, and a response characteristic to the wave is set according to a moving speed of the ship.

Further, the wave measuring system of the present invention is characterized in that the floating body has an arm which can protrude outward on the deck of the floating body, and the video camera is mounted on the tip of the arm. I have.

The wave measuring system according to the present invention is characterized in that the video camera is provided so that the camera angle can be adjusted.

In the above-described wave measurement system of the present invention, wave information can be obtained at low cost and with high accuracy by using an ordinary video camera mounted on a floating body without relying on special dedicated equipment as in the prior art. .

[0010] The floating body is configured as a ship,
If the response characteristics to the waves are set according to the moving speed of the ship, the waves can be measured without any trouble even when the ship is navigating.

When the video camera is mounted on the end of an arm provided on the deck of a ship so as to be able to protrude outward, the video camera is protruded outward from the hull only when the video camera is in use. Measurement is now performed, so that the video camera does not hinder the ship's operation such as berthing, and when the video camera is used, it is protruded sufficiently outboard to efficiently intersect the line of intersection between the ship's side and the wavefront. I can shoot properly well.

Further, if the video camera is provided so that the camera angle can be adjusted, the intersection between the side surface of the ship and the wavefront can be more appropriately photographed by adjusting the camera angle according to the draft of the ship. The advantage that can be obtained is obtained.

In addition, when analyzing the image of the intersection line photographed by the video camera, a plurality of analysis regions are set on the image, and the photographed image is photographed by one video camera as necessary. It is possible to determine the relative water level of the side of the floating body at a plurality of points from the image.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of a wave measuring system according to an embodiment of the present invention with reference to the drawings. FIG. 1 is a conceptual diagram of the system, and FIG. FIG. 3 is a block diagram showing the progress of the operation in the above system.

As shown in FIGS. 1 and 2, in the wave measuring system according to the present embodiment, a video for photographing an intersection 3 between a side surface 1a of a ship 1 as a floating body and a wave front 2 of a wave incident on the side surface 1a of the ship. A camera 4 is provided, and a signal of an image captured by the video camera 4 is input to an image processor 5 having image analysis means.

Then, the image processor 5 analyzes the image of the intersection line 3 to determine the relative water level at the side of the ship 1. Further, the image processor 5 corrects the relative water level based on the response characteristics of the ship 1 to the waves and corrects the relative water level to the waves 1 including the incident wave direction spectrum, the meeting angle, the significant wave height and the significant period of the waves 2 with respect to the ship 1. Wave information extracting means for extracting information is also provided. The wave information thus obtained is displayed on the display device 6 for safe operation support.

In this embodiment, since the present system is mounted on a ship, a response characteristic set according to the moving speed of the ship is used as the above-mentioned response characteristic. However, the present system is installed on a floating body that does not move such as a mooring buoy. When mounted, certain response characteristics can be used.

By the way, the relative water level fluctuation measured from the ship is different from the actual wave, but this is due to the following action. As the ship sails, the cycle of the measured wave changes. (Similar to Doppler effect) Waves are generated when a ship sails. (Occurs even in clear water.) An object called a ship breaks the wave flow field and deforms the waves. (Even if the ship is shaking or not sailing) Waves are generated by the shaking of the ship. Among them, is always constant without time fluctuation, and can be easily removed by processing such as time average. For the other,, an advanced processing method is required.

Such an advanced processing method is shown as a technique of so-called "hull wave height measurement", which regards a hull as an antenna for waves. (Pitch, roll, relative water level, acceleration) Considering regular waves as incident waves, the response characteristics can be calculated using a calculation method such as the strip method. be able to. Conversely, if the response characteristics are known, the wave causing the hull motion can be calculated backward. (Strictly speaking, the device needs to be devised in the following wave state).

In the actual sea area, the same processing can be performed by regarding a complicated wave field as a superposition of individual regular waves having different wavelengths and directions. However, considering the decomposition into regular waves having N different wavelengths and M different directions, N × M pieces of hull motion information are required to rigorously solve the simultaneous equations. However, the wave direction spectrum (individual regular waves) is estimated from about three to four types of information by the above-mentioned technique of measuring the hull wave height.

The above three or four types of hull motion information may be anything in principle. However, the hull motion information is easily responsive (has a large response characteristic) to the hull motion so that the antenna sensitivity varies depending on the frequency. There is a wavelength. For example, 1 /
Even if a wave with a wavelength of about 10 arrives, the ship does not shake, so pitching, rolling and acceleration cannot be used. Thus, the present invention takes into account the relative water level variation that can be used for a relatively wide range of wavelengths. That is, the relative water level fluctuation at three to four points may be measured, or the relative water level fluctuation one point + other information may be used. This is the same process as the above-mentioned "Holter wave height metering", but in the present invention, it is handled as "relative water level fluctuation measurement + hull motion correction", and FIG. 3 shows the procedure. I have.

As shown in FIG. 2, the video camera 4 is mounted on the end of an arm 8 provided on the side of the ship 1 so as to be able to protrude outward by a hinge 7 and thus photographed. The video camera 4 set at a possible position is further provided with a spindle mechanism 9 that can adjust the camera angle.

In the above-described wave measuring system of the present embodiment, the wave information can be obtained at low cost and with high accuracy by using a normal video camera mounted on the marine vessel 1 as a floating body without relying on special equipment as in the prior art. Can be obtained. Since the response characteristics to the waves are set according to the moving speed of the ship 1, the wave measurement can be performed without hindrance even when the ship 1 is navigating.

Further, since the video camera 4 is mounted on the distal end of the arm 8 provided on the deck of the boat 1 so as to be able to protrude outward, the video camera 4 is made to protrude outward only when used. As a result, wave measurement is performed, so that the video camera 4 does not become an obstacle when maneuvering at a shore or the like. The intersection line 3 can be efficiently and appropriately photographed.

Further, since the video camera 4 is provided so that the camera angle can be adjusted, the intersection 3 between the ship side surface 1a and the wavefront 2 can be formed by adjusting the camera angle according to the draft of the ship 1. The advantage is obtained that the photographing can be performed more appropriately.

In addition, when the image taken by the video camera 4 is analyzed by the image processor 5, a plurality of analysis areas on the image are set, so that relative water levels at a plurality of points are obtained as necessary. It is possible,
It can be used for extracting wave information.

[0027]

As described in detail above, according to the wave measuring system of the present invention, the following effects can be obtained. (1) Wave information can be obtained inexpensively and accurately using a normal video camera mounted on a floating body without relying on special dedicated equipment as in the past. (2) If the floating body is configured as a ship and the response characteristics to the waves are set according to the moving speed of the ship, the waves can be measured without any trouble even when the ship is navigating. (3) If the video camera is mounted on the tip of an arm provided on the deck of the ship so as to be able to protrude outward, the video camera can be protruded out of the hull only when used to measure waves. As a result, the video camera does not disturb the ship when maneuvering at a shore, etc., and when the video camera is used, it protrudes sufficiently out of the boat to make the intersection between the ship's side surface and the wavefront efficient and appropriate. Can be taken. (4) If the video camera is provided so that the camera angle can be adjusted, by adjusting the camera angle according to the draft of the ship, it is possible to more appropriately capture the intersection line between the ship side surface and the wavefront. Is obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a wave measurement system as one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation state of a video camera in the wave measurement system of FIG. 1 in a cross section of a hull.

FIG. 3 is a block diagram showing a progress of an operation in the wave measurement system of FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ship 1a Ship side surface 2 Wavefront 3 Intersecting line 4 Video camera 5 Image processor 6 Display device 7 Hinge 8 Arm 9 Camera angle adjustment support mechanism

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeshi Ishida 6-38-1 Shinkawa, Mitaka-shi, Tokyo Inside the Ship Research Institute of the Ministry of Transport (72) Inventor Tsuyoshi Miyazaki 2-1-1 Uchisaiwaicho, Chiyoda-ku, Tokyo F-term (Reference) 2F014 AA05 AB01 FA04

Claims (4)

[Claims] 1. A video camera for photographing an intersection of a side surface of the floating body with a wavefront of a wave incident on the side surface, and analyzing an image of the intersection taken by the video camera. Image analysis means for determining the relative water level of the side of the floating body, and correcting the relative water level determined by the image analysis means based on the response characteristics of the floating body to waves, the spectrum of the incident wave direction of the waves with respect to the floating body, A wave measuring system, comprising: wave information extracting means for extracting wave information including an angle of association, a significant wave height, and a significant period. 2. The wave measuring system according to claim 1, wherein the floating body is configured as a ship, and a response characteristic to the wave is set according to a moving speed of the ship. Measurement system. 3. The wave measuring system according to claim 2, wherein the floating body has an arm that can protrude outward on a deck of the floating body, and the video camera is mounted on a tip of the arm. Wave measurement system characterized by the following. 4. The wave measuring system according to claim 3, wherein the video camera is provided so that a camera angle can be adjusted.