JP2007225493A - Log speed measuring device for ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a log speed measuring device for a ship, capable of measuring the log speed of the ship from relative backward movement of the same bubble with respect to the hull of the ship using a simple means, while focusing on a large number of bubbles generated on the surface of a relative flow of water, along the shipside during sailing. <P>SOLUTION: The log speed measuring device is provided with: a camera 4, mounted on a tip part of an arm 3 overhanging from the ship 1, to a side direction toward a water surface W below so that the camera is not affected by the outside water boundary layer along the side surface of the ship; a shutter operational means 4a for photographing the bubble B floating on the water surface W by the camera 4 at a required time interval; and a range finding means 5 measuring the distance between the camera 4 and the water surface W. The relative moving distance of the bubble along the shipside at the required time interval is obtained, on the basis of mutual comparison of a plurality of imaging data of the same bubble B and the measurement data of the range finding means 5, and the log speed of the ship is calculated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a marine water speed measurement device capable of measuring the water speed of a ship in operation.

Various electromagnetic logs and acoustic logs (Doppler logs) have been developed as means for measuring the water velocity of a ship. The electromagnetic log uses Faraday's law of electromagnetic induction. When the magnetic field generated by the sensor with the coil at the tip of the measuring rod protruding from the bottom of the vessel cuts seawater, the electromagnetic log is relative to the pair of electrodes attached to the tip of the sensor. It is a device that measures the water speed of a ship by an electromotive force generated in proportion to the speed. The acoustic log is equipped with a transducer on the bottom of the ship, and obtains the water velocity of the ship by calculating the frequency shift (Doppler shift) between the emission frequency and the reflection frequency.
However, the measured water speed measured by electromagnetic logs and acoustic logs includes the influence of the navigating hull, mainly the influence of the boundary layer developed on the hull surface. Cannot be detected.
JP-A-9-5348 JP-A-9-196956 JP 2005-292011 A

  The present invention avoids the influence of the portion of the water flow relative to the hull in order to avoid the influence of the portion of the hull surface near the hull surface, which is a problem with electromagnetic logs and acoustic logs, due to the friction between the hull and the fluid. In order not to be affected, the image of bubbles on the surface of the water away from the hull to the side (those whose contours can be identified as a collection of fine bubbles) is processed over time, and the water speed of the ship by simple means It is an object of the present invention to provide a marine water speed measurement device that can measure water.

  A marine water speed measuring device according to the present invention includes an arm projecting upward from a water surface on the side of the ship and a camera mounted downward on the tip of the arm to detect the water speed of the ship. And a shutter operating means for photographing a number of bubbles generated on a surface of a relative water flow along a ship side of the ship during the navigation of the ship at a predetermined time interval by the camera, and the shutter A distance measuring means for measuring the distance between the camera and the water surface when the operation means is operated, a mutual comparison of a plurality of photographing data of the bubbles sequentially photographed according to the operation of the shutter operating means, and the distance measuring means The bubble movement measuring means for measuring the relative movement distance in the captain direction of the foam with respect to the ship side portion based on the measurement data, and the relative movement distance and the movement distance of the foam determined by the bubble movement measuring means In Calculator and is characterized in that provided for calculating the-water speed of the ship and a response to the above time intervals.

  In addition, the marine water speed measurement device of the present invention is attached to an arm that protrudes upward from the water surface on the side of the marine vessel and a tip of the arm downward to detect the water velocity of the marine vessel. A video camera, and a shutter operation for continuously shooting a number of bubbles generated on the surface of the relative water flow along the side of the ship during the navigation by the video camera over the required time. A distance measuring means for measuring a distance between the video camera and the water surface when the shutter operating means is operated, and relative to the ship of the bubbles continuously photographed according to the operation of the shutter operating means. Based on the movement image and the measurement data of the distance measuring means, the relative movement distance of the foam with respect to the ship side and the required time corresponding to the movement distance from the ship side, and the water speed of the ship. It is characterized in that the computing unit and is provided for calculating a.

  Furthermore, the marine water velocity measuring device of the present invention is characterized in that the arm is provided so as to be retractable to the inner side of the ship side.

  In the marine water velocity measuring device of the present invention, the bubbles generated on the surface of the relative water flow along the ship side of the vessel being navigated are not affected by the outer water boundary layer along the ship side. Images are taken at the required time interval (for example, 1/30 second) by the downward-facing camera at the tip of the arm that protrudes toward the camera, and the shape is identified from the multiple shooting data. The relative movement distance of the same bubble to the rear of the hull in the time interval can be measured, and the water speed of the hull as a ratio to the time interval can be easily obtained by the calculator.

  In addition, when a video camera is provided as a bubble photographing means on the water surface on the side of the hull, the movement of the bubbles is continuously photographed over a required time by the shutter operation means of the video camera, and the video camera and the above Since the distance to the water surface is measured by the distance measuring means, it is based on the image of the relative movement of the bubbles with respect to the ship taken continuously according to the operation of the shutter operating means and the measurement data of the distance measuring means. From the relative movement distance of the same foam along the side of the ship and the required time corresponding to the movement distance, the water speed of the ship can be easily obtained by the calculator.

  The arm on which the camera or video camera is mounted is stored inside the ship when not in use, so that there will be no problem when the hull is berthed.

  FIG. 1 is a perspective view schematically showing a ship provided with a marine water speed measuring device as one embodiment of the present invention, FIG. 2 is a front view showing a use state of the device of FIG. 1, and FIG. It is explanatory drawing which shows the aspect of the water speed measurement of a ship typically.

  As shown in FIG. 1 and FIG. 2, in the hull parallel part of the ship 1, an arm 3 is provided on the deck 1 a so as to protrude above the water surface W via the pedestal 2. A camera (preferably a CCD camera) 4 mounted toward the lower water surface W is provided.

And the shutter operation means 4a of the camera 4 is comprised so that it can operate | move by the remote apparatus which is not shown inboard.
Further, a distance measuring means 5 for measuring a distance D between the camera 4 and the water surface W is provided at the tip of the arm 3 in conjunction with the operation of the shutter operating means 4a.

Further, as shown in FIG. 1 and FIG. 3, the relative movement distance E in the length direction with respect to the side of the ship for t seconds of the same bubble B on the water surface taken by the camera 4 in accordance with the operation of the shutter operation means 4a, A bubble image measuring device 6 that can be measured as corresponding to the positional change amount e of the images b ₁ and b ₂ of the bubble B is provided.

In the marine water speed measurement device of the above-described embodiment, at the time of navigation of the ship, it is at a position away from the side of the ship via the arm 3 so as not to be affected by the boundary layer of the water flow along the side of the ship. For example, based on the relative movement distance e of the _two images b ₁ and b _{2 obtained} by photographing the same bubble B by the camera 4 provided with the high-speed shutter operation means 4a that can be photographed at a time interval of 1/30 seconds, By taking into account the scale (for example, 1/10) of the camera image at a distance D (for example, 3 meters) corresponding to the characteristics of the camera 4, the actual distance E of the relative movement distance of the bubble B with respect to the hull is obtained. Can be found at

That is, when the relative movement distance e of the images b ₁ and b ₂ of the same bubble B photographed at a time interval of 1/30 seconds is 17.1 mm, for example, the actual relative movement distance of the bubble B is Considering the scale 1/10 of the camera image at a distance of 3 meters and the time interval of 1/30 seconds, the speed is 17.1 mm × 10 × 30 per second, that is, 5.13 m per second. 1 knot is 1852 m / h, and is calculated as about 10 knots using the computing unit 7 according to the formula [1].
[Equation 1]
V = 5.13 × 60 × 60 / 1852≈10

  As shown in FIG. 1, in this embodiment, the arm 3 can be retracted to the inside of the ship side by rotating as shown in the chain line using the electric rotary drive device 3A when the device is not in use. In this way, consideration is given so as not to cause any trouble when the ship berths.

  In the above-described embodiment, the camera 4 is used as a still camera. However, a video camera (preferably a CCD system) may be used as the camera 4, and in this case, an image at a specific time of a certain bubble is used. Thus, the moving distance of the image on the same bubble screen after the required time is obtained, and in this way, the water speed of the ship can be measured by the same means as in the above-described embodiment.

  That is, when a video camera is provided as a bubble photographing means on the water surface on the side of the hull, the movement of the bubbles is continuously photographed over the required time by the shutter operation means of the video camera, and the video camera and the above Since the distance to the water surface is measured by the distance measuring means, it is based on the image of the relative movement of the bubbles with respect to the ship taken continuously according to the operation of the shutter operating means and the measurement data of the distance measuring means. From the relative movement distance of the same foam along the side of the ship and the required time corresponding to the movement distance, the water speed of the ship can be easily obtained by the calculator.

  In this case as well, the arm equipped with the video camera is stored inside the ship side when not in use, as in the case of the above-described embodiment, and consideration is given so as not to cause trouble when the hull is berthed. .

  It should be noted that the relative movement of the bubbles on the water surface W with respect to the ship side may be obtained as the movement distance in the direction of the ship length in the minute time of the water surface pattern (luminance pattern) due to the plurality of bubbles. The water speed of the ship can be obtained by the same method as in the example.

It is a perspective view which shows the mounting state to the ship of the marine water velocity measuring device as one Example of this invention. It is a front view which shows the use condition of the apparatus of FIG. It is explanatory drawing which shows the aspect of an effect | action in the marine water speed measurement apparatus shown to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ship 1a Deck 2 Pedestal 3 Arm 3A Electric rotation drive device 4 Camera 4a Shutter operation means 5 Distance measuring means 6 Bubble image measuring instrument 7 Calculator B Bubble b ₁ and b ₂ Bubble image D Distance e Relative of bubble image Travel distance EE Actual size t Time interval V Water speed (speed)
W Water surface

Claims (3)

  In order to detect the water speed of the ship, an arm projecting upward from the water surface on the side of the ship and a camera mounted downward on the tip of the arm are provided. Shutter operating means for photographing a large number of bubbles generated on the surface of the relative water flow along the ship side of the ship at a required time interval by the camera, and the camera and the water surface when the shutter operating means is operated A distance measuring means for measuring the distance between the bubble and the ship side of the bubble based on the mutual comparison of a plurality of photographing data of the foam sequentially photographed according to the operation of the shutter operating means and the measurement data of the distance measuring means From the bubble movement measuring means for measuring the relative movement distance in the captain direction with respect to the section, and the relative movement distance of the foam obtained by the bubble movement measurement means and the time interval corresponding to the movement distance. Characterized in that the calculator for calculating the to water velocity is provided, marine-water velocity measuring device.   In order to detect the water speed of the ship, an arm projecting upward from the water surface on the side of the ship and a video camera mounted downward on the tip of the arm are provided during the navigation of the ship. Shutter operating means for continuously photographing a number of bubbles generated on the surface of the relative water flow along the ship side of the ship over the required time by the video camera, and the video at the time of operating the shutter operating means Ranging means for measuring the distance between the camera and the water surface, an image of the relative movement of the bubbles with respect to the ship taken continuously in response to the operation of the shutter operating means, and measurement data of the ranging means And a computing unit for calculating the water velocity of the ship from the relative movement distance of the foam with respect to the ship side in the length direction and the required time corresponding to the movement distance. And wherein, marine-water velocity measuring device.   The marine water speed measuring device according to claim 1, wherein the arm is provided so as to be retractable to an inner side of the ship side.

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