JP7699617B2 - Inspection method and inspection device - Google Patents

Description

The present invention relates to an inspection method and inspection device for inspecting the fouling condition of the exterior wall surface of a ship, and more specifically, to an inspection method and inspection device that can efficiently inspect the fouling condition of the exterior wall surface of a ship.

In recent years, there has been a demand to prevent the movement of marine organisms such as algae and shellfish attached to ships. It is desirable to be able to check whether a ship is fouled by algae or the like before it enters a port, and in order to grasp the fouling condition of the ship before entering a port and determine whether it can enter the port or not, it is necessary to grasp the overall fouling condition of the ship efficiently in a relatively short time. Various underwater robots have been proposed for inspecting the fouling condition of the exterior wall surfaces of ships (see, for example, Patent Document 1). Patent Document 1 discloses the configuration of an underwater robot that moves along the exterior wall surface and acquires data showing the condition of the exterior wall surface using sensors or the like.

The underwater robot in Patent Document 1 is very small compared to the size of the exterior wall of a ship, so it takes a lot of time to inspect the entire ship. Furthermore, if the water is murky, the murkiness of the water makes the exterior wall of the ship invisible when attempting to take a picture from a distance. The camera of the underwater robot needs to be brought close to the exterior wall of the ship, which reduces the range of images that can be captured by the camera. This makes it extremely difficult to determine which position on the ship the image captured by the camera corresponds to. Furthermore, the underwater robot in Patent Document 1 is designed to be used on ships at sea, so it cannot be used to inspect ships at anchor.

Japanese Patent Application Publication No. 2022-535681

The present invention was made in consideration of the above problems, and its purpose is to provide an inspection method and inspection device that can efficiently inspect the fouling condition of the exterior wall surface of a ship.

An inspection method for achieving the above-mentioned object is an inspection method for inspecting the contamination condition of the outer wall surface of a ship, the inspection method comprising: underwater equipment having a camera; and a processing mechanism for acquiring data from the underwater equipment, the underwater equipment having a mirror arranged at a position in the shooting direction of the camera; and a case having at least a part of its wall surface made of a transparent material and filled with a transparent gas or liquid inside, and a configuration in which the optical distance from the camera to the mirror is set greater than the optical distance from the mirror to the outer wall surface, the inspection method comprising: a horizontal position selection step for selecting an inspection position within a range from the bow to the stern of the ship; a photographing step for the camera to acquire an image of the outer wall surface through the gas or liquid filled in the case and the mirror while moving the underwater equipment having the camera in the vertical direction at the inspection position selected in the horizontal position selection step; and an acquisition step in which the processing mechanism acquires data from the underwater equipment, the horizontal position selection step, the photographing step, and the acquisition step being repeatedly executed.

An inspection device for achieving the above-mentioned object is an inspection device for inspecting the contamination condition of the outer wall surface of a ship, and is equipped with underwater equipment having a camera and a processing mechanism for acquiring data from the underwater equipment, wherein the underwater equipment has a mirror positioned in a position in the shooting direction of the camera, and a case whose wall surface is at least partially made of a transparent material and filled with a transparent gas or liquid, and is configured so that the optical distance from the camera to the mirror is set greater than the optical distance from the mirror to the outer wall surface, and the camera is configured to acquire an image of the outer wall surface through the gas or liquid filled in the case and the mirror, and the underwater equipment acquires the image of the outer wall surface while moving in an up and down direction.

According to the present invention, by acquiring images in the vertical direction at multiple inspection positions from the bow to the stern of the ship, it is possible to grasp the overall state of contamination on the exterior wall surface of the ship. This is advantageous for efficiently inspecting the state of contamination on the exterior wall surface of the ship.

FIG. 1 is an explanatory diagram illustrating an outline of an inspection device. FIG. 1 is an explanatory diagram illustrating an outline of a ship. FIG. 11 is an explanatory diagram illustrating an example of data acquired by a processing mechanism. FIG. 1 is an explanatory diagram illustrating a flow of an inspection method. FIG. 11 is an explanatory diagram illustrating an example of an appearance image. FIG. 2 is an explanatory diagram illustrating a guide mechanism installed on a ship. 7 is an explanatory diagram illustrating the guide mechanism of FIG. 6 as viewed along the arrows AA. 8 is an explanatory diagram illustrating a modified example of the guide mechanism in FIG. 7 . 11 is an explanatory diagram illustrating a state in which the guide mechanism is tilted. FIG. FIG. 11 is an explanatory diagram illustrating an example of an appearance image. 1. FIG. 4 is an explanatory diagram illustrating a modified example of the underwater equipment of FIG. 12 is an explanatory diagram illustrating the underwater equipment of FIG. 11 as viewed along the arrows BB. 12 is an explanatory diagram illustrating data acquired by the underwater equipment of FIG. 11 . 12 is an explanatory diagram illustrating a modified example of the underwater equipment in FIG. 11 . 15 is an explanatory diagram illustrating the underwater equipment of FIG. 14 as viewed along the CC arrows. 15 is an explanatory diagram illustrating a modified example of the underwater equipment in FIG. 14 . 15 is an explanatory diagram illustrating a modified example of the underwater equipment in FIG. 14 . 18 is an explanatory diagram illustrating the underwater equipment of FIG. 17 as viewed along the arrows D-D. 19 is an explanatory diagram illustrating the underwater equipment of FIG. 18 as viewed along arrows E-E.

The inspection method and inspection device will be described below based on the embodiment shown in the figure. In the figure, the length direction of the ship, which is the direction connecting the bow and stern of the ship, is indicated by arrow y, the width direction of the ship, which crosses the length direction y at a right angle, is indicated by arrow x, and the up-down direction is indicated by arrow z.

As shown in FIG. 1, the inspection device 1 includes an underwater device 2 and a processing mechanism 3 that acquires data from the underwater device 2. The underwater device 2 includes a main body 2a and a camera 4 that is installed on the main body 2a. The main body 2a is configured, for example, in a cylindrical shape. The main body 2a may have cone-shaped members disposed at the upper and lower ends. The camera 4 can acquire at least one of video and still images.

The processing mechanism 3 is connected to the underwater device 2 via a cable 5. The cable 5 is composed of a signal line that sends data of images captured by the camera 4, for example, to the processing mechanism 3. The cable 5 may also include an electric wire that supplies power from the processing mechanism 3 to the underwater device 2. The processing mechanism 3 may be composed of various known computers. The processing mechanism 3 has a central processing unit (CPU), a main memory unit (memory), and an auxiliary memory unit (e.g., a HDD). The processing mechanism 3 may be configured to be installed in the main body 2a of the underwater device 2.

The underwater device 2 may have a pair of auxiliary structures 2b arranged on either side of the main body 2a. The auxiliary structure 2b may be configured, for example, in a cylindrical shape. The auxiliary structure 2b may have cone-shaped members arranged at the upper and lower ends. Each auxiliary structure 2b may also have two arms 2c arranged between it and the main body 2a.

The inspection device 1 may include a position detection mechanism 6 that is installed, for example, inside the main body 2a. The position detection mechanism 6 has a configuration for acquiring position information of the underwater device 2, and is configured, for example, by a depth gauge.

By having a configuration with a pair of auxiliary structures 2b, the underwater device 2 can suppress rotation (hereinafter sometimes referred to as skew) around the central axis in the vertical direction z.

The underwater device 2 may have a number of thrusters 7, each of which is composed of a propeller connected to a motor. The thrusters 7 are installed, for example, on the main body 2a or the auxiliary structure 2b. The configuration having the thrusters 7 allows the underwater device 2 to control its movement in the vertical direction z underwater. The thrusters 7 also allow the underwater attitude of the underwater device 2 to be controlled. Here, the attitude of the underwater device 2 refers to the inclination of the underwater device 2 about the central axis in the width direction x, the length direction y, or the vertical direction z.

The underwater device 2 may have a ballast tank 8, for example, installed on the auxiliary structure 2b. The ballast tank 8 can control the flow of water in and out of the outside. With a configuration that has the ballast tank 8, it is possible to sink the underwater device 2 with water injected into the ballast tank 8, and to cause the underwater device 2 to float by buoyancy by draining the water from the ballast tank 8. The ballast tank 8 may be installed on the main body 2a. It is also possible to control the attitude of the underwater device 2 by arranging the ballast tank 8 on each of the pair of auxiliary structures 2b and controlling the flow of water in and out of each. The underwater device 2 may have both the thruster 7 and the ballast tank 8, or only one of them.

The underwater device 2 preferably has a light 9, for example, installed on the main body 2a. The light 9 enables the camera 4 to take pictures even at relatively deep places or at night where there is insufficient light. The light 9 may be installed on the auxiliary structure 2b. Multiple lights 9 may be installed on the underwater device 2.

As shown in FIG. 2, in a ship 10 at anchor, such as a tanker or container ship, one inspection position P is selected in the range from the bow to the stern of the ship 10 (horizontal position selection step S1). In the case of a ship 10 having a length of 300 m in the length direction y, for example, the inspection positions P can be set every 15 m. In this case, 20 inspection positions P1-20 are set on the port side, and 20 inspection positions P21-40 are set on the starboard side. The method of setting the inspection positions P is not limited to the above. The intervals between the inspection positions P do not need to be limited to equal intervals. In addition, the number of inspection positions P does not need to be 40 points on both sides in total, and may be set to, for example, 10 points or 50 points or more on both sides in total. A configuration in which the inspection positions P are set only on one of the port side or starboard side may also be used.

In the horizontal position selection step S1, one inspection position P, such as inspection position P3, is selected from among the pre-set inspection positions P.

Next, the underwater device 2 is lowered from the upper deck 10a at the selected inspection position P3. The underwater device 2 descends underwater, for example, by its own weight. While the underwater device 2 is being lowered, the outer wall surface 10b of the ship 10 is photographed (photographing step S2). The underwater device 2 photographs the area from the upper deck 10a to the bottom 10c of the ship while descending in the vertical direction z. After the underwater device 2 is lowered to the vicinity of the bottom 10c of the ship, it may be photographed while ascending. It may also be photographed both while the underwater device 2 is descending and while ascending. The underwater device 2 ascends, for example, by winding up the cable 5. The underwater device 2 may be connected to a rope separate from the cable 5 and may be configured to ascend by winding up the rope. The area photographed by the underwater device 2 is not limited to the area below the water surface. The area above the water surface may also be photographed. In FIG. 2, the soiled portion 11 of the outer wall surface 10b is indicated by diagonal lines for the sake of explanation.

The configuration is not limited to placing the inspection device 1 on the ship 10 to perform the inspection. A small vessel on which the inspection device 1 is placed may be brought close to the ship 10 to be inspected, and the underwater equipment 2 may be lowered from the small vessel to take photographs. In this case, the position of the small vessel relative to the ship 10 is selected in the horizontal position selection step S1. The worker performing the inspection can perform the inspection without boarding the ship 10 to be inspected.

As illustrated in FIG. 3, the processing mechanism 3 acquires data from the underwater equipment 2 (acquisition step S3). The data acquired by the processing mechanism 3 includes image data captured by the camera 4. The image data may be video or still images, or both. In the case of video, for example, a series of images from the upper deck 10a to the bottom of the ship 10c, or a series of images from the water surface to the bottom of the ship 10c, are acquired. In the case of still images, multiple images are acquired at a predetermined interval over time or a distance in the vertical direction z.

The data acquired by the processing mechanism 3 may include horizontal position information corresponding to the image data. The horizontal position information is composed of a number that distinguishes between multiple inspection positions P or coordinate data of the inspection positions P. It can also be said that the horizontal position information is composed of data indicating a position on the ship 10. In the embodiment of FIG. 3, the number of the inspection position P at which the image data was acquired is included as the horizontal position information. For example, it becomes possible to distinguish between image data corresponding to inspection position P1 and image data corresponding to inspection position P3.

The data acquired by the processing mechanism 3 may include position information in the vertical direction z corresponding to the image data. The position information in the vertical direction z is composed of the water depth of the shooting range. The position information in the vertical direction z may be data that directly or indirectly indicates the water depth. The position information of the underwater device 2 is acquired, for example, by a position detection mechanism 6 installed in the underwater device 2. The position detection mechanism 6 is composed of, for example, a pressure sensor or a depth gauge installed in the underwater device 2. The processing mechanism 3 can acquire the position information in the vertical direction z corresponding to the image data by the pressure sensor or the depth gauge. The position detection mechanism 6 is not limited to being installed in the underwater device 2. For example, the position detection mechanism 6 may be composed of an encoder installed on the upper deck 10a that detects the amount of cable 5 being paid out. The water depth of the underwater device 2 may be acquired based on the amount of cable 5 being paid out from the upper deck 10a to the underwater device 2. The position detection mechanism 6 is composed of, for example, a program stored in the processing mechanism 3. The program may be configured to estimate the water depth based on the speed and time at which the underwater device 2 descends from the water surface. The program may be configured to, for example, calculate the speed and direction of movement of the underwater device 2 from images acquired by the camera 4, and estimate the position of the underwater device 2.

The configuration of the position detection mechanism 6 is not limited to the above. The position detection mechanism 6 only needs to have a configuration capable of acquiring position information in the vertical direction z corresponding to the image data. In addition, the position detection mechanism 6 may have a configuration capable of acquiring position information in the horizontal direction corresponding to the image data. The position detection mechanism 6 is not a required component of the inspection device 1.

The position detection mechanism 6 may be configured to acquire horizontal position information. The position detection mechanism 6 may be configured, for example, by a Global Navigation Satellite System (GNSS) antenna installed in the underwater device 2. The position detection mechanism 6 may also be configured by a positioning system that uses ultrasonic waves. The position detection mechanism 6 may be configured, for example, by an acceleration sensor installed in the underwater device 2. The acceleration sensor estimates the position of the underwater device 2 from an accumulation of the amount of change in acceleration. These position detection mechanisms 6 can acquire the coordinates of the underwater device 2 in three-dimensional space as position information. The position information consisting of coordinates in three-dimensional space includes position information in the vertical direction z and horizontal direction corresponding to the image data.

The position detection mechanism 6 may be configured with a combination of the above devices. For example, the position detection mechanism 6 may be configured with a GNSS and an ultrasonic positioning system, and position information may be obtained by the GNSS when the underwater device 2 is on the water, and by the ultrasonic positioning system when the underwater device 2 is underwater.

While the camera 4 is taking pictures in the photographing step S2, the image data may be configured to have location information added to it and sent to the processing mechanism 3. In this case, the underwater device 2 sends the image data and location information to the processing mechanism 3 while taking pictures with the camera 4. It can be said that the photographing step S2 and the acquisition step S3 are performed simultaneously.

The acquisition step S3 may be performed after the photographing step S2 is completed. In this case, data is transferred from the underwater device 2 to the processing mechanism 3 after the photographing step S2 is completed. When the underwater device 2 is underwater, the data is stored in a memory mechanism installed in the underwater device 2. The inspection device 1 of this embodiment may be configured without the cable 5.

Photographing by the underwater equipment 2 is repeated multiple times while changing the inspection position P from P1 to, for example, P40. In other words, the horizontal position selection step S1, the photographing step S2, and the acquisition step S3 are executed repeatedly. Multiple inspection devices 1 may be used to perform inspections simultaneously. For example, two inspection devices 1 may be used, with one inspection device 1 inspecting the port side inspection position P1-20 and the other inspection device 1 inspecting the starboard side inspection position 21-40.

The dirt condition of the outer wall surface 10b can be evaluated from the data of multiple images. As shown in FIG. 3, the image data shows the condition of the outer wall surface 10b at least in the range from the water surface (0 m depth) to the bottom of the ship 10c (15 m depth). For example, from the images of inspection positions P2 and P3, it is easy to imagine that the dirtied portion 11 spreads horizontally at a depth of about 6 m. Also, from the image of inspection position P20, it is easy to imagine that the dirtied portion 11 is located at a depth of about 10 m, and therefore the dirtied portion 11 at inspection position P2 spreads horizontally while shifting downward to inspection position P20. In FIG. 3, the dirtied portion 11 is shaded for the sake of explanation. Also, data for inspection positions P4 to P19 is omitted in FIG. 3.

By acquiring images at multiple inspection positions P using the inspection device 1 in the longitudinal direction y from bow to stern of the ship 10, it is possible to grasp the overall fouling condition of the exterior wall surface 10b of the ship 10. Fouling caused by marine organisms such as algae and shellfish tends to spread horizontally. Therefore, by acquiring images in the vertical direction z at multiple inspection positions P, it is possible to estimate the overall fouling condition of the exterior wall surface 10b.

In the photographing step S2, the underwater device 2 is configured to move only in the vertical direction z, so the position of the part shown in the image can be determined by determining its position in the vertical direction z.

The underwater device 2 can move in the vertical direction z without using water currents, making it possible to inspect the fouling condition of the ship 10 while it is anchored.

As shown in FIG. 4, the processing mechanism 3 may be configured to execute a judgment step S4 for judging whether or not photographing has been completed at all pre-set inspection positions P. After it is judged in judgment step S4 that there is no next inspection position P, the processing mechanism 3 may be configured to execute an exterior image generation step S5 for generating an exterior image that reproduces the entire exterior wall surface 10b. The processing mechanism 3 executes the exterior image generation step S5. When an exterior image is generated, the image data has at least position information in the vertical direction z. It is desirable that the image data has position information in the horizontal direction and the vertical direction z.

As shown in FIG. 5, the exterior image 12 is arranged with data of multiple images based on position information in the horizontal direction and the vertical direction z. In the exterior image generation step S5, the vertical direction z position of each image is adjusted while, for example, the water surface position (water depth 0 m) and the position of the bottom of the ship 10c (water depth 15 m) are aligned. For example, multiple images on the port side are generated as one exterior image 12 while adjusting the relative positions in the vertical direction z and the length direction y. In the exterior image generation step S5, for example, one exterior image 12 is generated on the port side and one exterior image 12 is generated on the starboard side. In FIG. 5, the range of the exterior image 12 is shown with a dashed line for the purpose of explanation. The range inside the dashed line is generated as the exterior image 12. The exterior image 12 is displayed on, for example, a monitor connected to the processing mechanism 3. In FIG. 5, the interval between the image data in the length direction y is shown narrow for the purpose of explanation. In reality, the range shown in the data of one image in the length direction y is, for example, 1 m, and the interval between the data of adjacent images is, for example, 15 m.

The degree of soiling is determined based on this exterior image 12. As illustrated in FIG. 5, the exterior image 12 has many areas where image information is missing, but it is as if the entire exterior wall surface 10b is being observed. From the exterior image 12, it is easy to estimate the extent of the soiled area 11 in areas where images have not been acquired. For the sake of explanation, the area estimated to be the soiled area 11 is shown by a dashed line in FIG. 5. Generating the exterior image 12 makes it easier to determine the degree of soiling.

As shown in FIG. 4, the configuration may include a complementation step S5a that estimates the condition of the range where image data cannot be obtained and complements the appearance image 12. The processing mechanism 3 executes the complementation step S5a. In the complementation step S5a, for example, the range of the soiled portion 11 is estimated, and this range is added to the appearance image 12. For example, the dashed line shown in FIG. 5 is added to the appearance image 12.

In the complementation step S5a, the soiled areas 11 are extracted from the data of the individual images by image processing. For example, the soiled areas 11 are extracted by image processing such as binarization processing and edge detection processing. In the data of adjacent images, the boundaries of the soiled areas 11 that are closest in the vertical direction z are connected by a straight line (see the dashed and dotted line in Figure 5). This complements the soiled areas 11 in the exterior image 12. It can be estimated that the area surrounded by the dashed and dotted line is the soiled area 11. By displaying the area of the soiled area 11 in the exterior image 12, it becomes easier to grasp the area of the soiled area 11 on the entire exterior wall surface 10b.

The system may be configured so that a worker executes the completion step S5a. The worker looks at the image data and extracts the range of the stained portion 11. The worker adds a boundary line to the range in the exterior image 12 where the stained portion 11 is estimated to extend. For example, the worker adds a dashed line as shown in FIG. 5 to the exterior image 12.

As shown in FIG. 4, the system may have a configuration in which a contamination state determination step S6 is executed to determine the contamination state from the exterior image 12. The processing mechanism 3 executes the contamination state determination step S6. The processing mechanism 3 calculates the ratio of the contamination portion 11 to the exterior wall surface 10b in the exterior image 12 (hereinafter, sometimes referred to as the contamination degree), and determines the contamination state based on this contamination degree. The higher the contamination degree, the more severe the contamination state. Specifically, the range from the water surface to the bottom of the ship 10c in the exterior image 12 in FIG. 5 is calculated as the area of the exterior wall surface 10b. In addition, the area of the contamination portion 11 shown by the diagonal lines and the estimated range surrounded by the dashed line are calculated as the range of the contamination portion 11. The contamination degree is calculated from the two areas. In other words, the contamination degree is calculated including the range complemented in the complement step S5a. The range from the upper deck 10a to the bottom of the ship 10c may be calculated as the area of the exterior wall surface 10b. In this case, the upper deck 10a must be included in the data of each image.

By carrying out an inspection before entering port, it becomes possible to take measures such as refusing entry into port if the degree of contamination exceeds a preset threshold, such as 10%. Furthermore, when inspecting the ship, it may be possible to determine whether or not the exterior wall surface 10b needs to be cleaned depending on the degree of contamination. The configuration for calculating the degree of contamination makes it possible to quantitatively evaluate the degree of contamination of the exterior wall surface 10b of the ship 10.

The method of calculating the degree of contamination is not limited to the above. It is sufficient if the method has a configuration that can quantitatively evaluate the extent of the contaminated area 11. For example, the method may have a configuration that calculates the degree of contamination without including the complemented area. Specifically, the area from the water surface to the bottom of the ship 10c in the image data of Figure 5 is calculated as the area of the outer wall surface 10b. In addition, the area of the contaminated area 11 shown with diagonal lines is calculated. The degree of contamination is calculated from the two areas. The above method can be used to calculate the degree of contamination even if the inspection method does not have the appearance image generation step S5 or the complementation step S5a.

The system may be configured so that an operator executes step S6 for determining the state of contamination. The operator may check the data of the exterior image 12 or multiple images, and calculate and evaluate the degree of contamination based on the data.

As shown in FIG. 6, the inspection device 1 may include a guide mechanism 13 that extends in the vertical direction z and is positioned near the outer wall surface 10b. In this embodiment, the guide mechanism 13 has a wire 14 that is stretched in the vertical direction z, and a weight 15 that is positioned near the lower end of the wire 14. The wire 14 has at least a length that allows the underwater device 2 to move to the vicinity of the bottom of the vessel 10c.

The guide mechanism 13 may have a support mechanism 16 for suspending the wire 14 from the upper deck 10a. The support mechanism 16 protrudes from the upper deck 10a toward the sea. The support mechanism 16 holds the wire 14 at a position, for example, 1 m toward the sea from the outer wall surface 10b. The support mechanism 16 is also configured to be movable along the length direction y on the upper deck 10a. In the horizontal position selection step S1, the guide mechanism 13 is moved together with the inspection device 1 to match a preset inspection position P.

As shown in FIG. 7, the underwater device 2 is connected to the wire 14 via a pair of connectors 17 spaced apart in the vertical direction z. In the photographing step S2, the underwater device 2 moves while being guided by the wire 14 of the guide mechanism 13. Because the underwater device 2 is connected to the wire 14 by the pair of connectors 17, rotation of the underwater device 2 about the central axis in the length direction y or width direction x can be suppressed. In this embodiment, the underwater device 2 does not have an auxiliary structure 2b.

As illustrated in Figures 6 and 7, the configuration including the guide mechanism 13 can suppress the problem of the underwater device 2 unintentionally moving in the horizontal direction (length direction y and width direction x). The underwater device 2 can descend or ascend almost straight along the outer wall surface 10b, improving the accuracy of the position information corresponding to the image data.

As shown in FIG. 8, the guide mechanism 13 may have two wires 14. A weight 15 is disposed near the lower ends of the two wires 14. The underwater device 2 is connected to one of the wires 14 via a pair of connectors 17 spaced apart in the vertical direction z, and is connected to the other wire 14 via another pair of connectors 17. Because the underwater device 2 is connected to the two wires 14 by the connectors 17, rotation of the underwater device 2 about the vertical direction z as a central axis in addition to the length direction y and width direction x can be suppressed. The underwater device 2 can photograph the outer wall surface 10b straight from the front. The accuracy of the position information corresponding to the image data can be further improved.

The configuration of the guide mechanism 13 is not limited to the above. The guide mechanism 13 may be configured with a rail, which is less prone to deformation than a wire. The rail is configured with a steel material, such as rolled steel, extending in the vertical direction z. In this case, a weight may or may not be placed near the bottom end of the rail. This is advantageous for suppressing rotation of the underwater device 2 about the central axis in the length direction y, width direction x, and vertical direction z. Furthermore, since rails are less prone to deformation and are heavier than wires, they are less susceptible to the effects of currents and wind. This is advantageous for lowering the underwater device 2 straight down parallel to the vertical direction z.

The underwater device 2 may be configured to move using a drive mechanism such as wheels relative to the rails that make up the guide mechanism 13. For example, a rack may be formed on the rails, and a pinion gear may be disposed on the underwater device 2. This is advantageous for precisely controlling the movement speed of the underwater device 2 in the vertical direction z.

As shown in FIG. 9, the inspection device 1 may be equipped with an attitude detection mechanism 18 that detects the inclination of the underwater equipment 2 or the guide mechanism 13. The attitude detection mechanism 18 is configured, for example, with an inclinometer that is installed on the support mechanism 16 and detects the inclination θ of the wire 14 relative to the vertical direction z. The inclinometer is installed on a sheave or the like that is installed on the support mechanism 16 and around which the wire 14 is wound.

The attitude detection mechanism 18 is, for example, installed in the underwater device 2 and is composed of an inclinometer, gyroscope, acceleration sensor, or optical gyroscope that detects the inclination θ of the underwater device 2 relative to the vertical direction z. The attitude detection mechanism 18 may be installed in both the underwater device 2 and the guide mechanism 13. In acquisition step S3, the processing mechanism 3 acquires the value of the inclination θ from the attitude detection mechanism 18 as well as the position information of the underwater device 2.

The inspection device 1 is configured with an attitude detection mechanism 18, so that the tilt θ of the image captured by the underwater device 2 in the vertical direction z can be obtained. The tilt θ indicates the tilt of the underwater device 2 with the width direction x as the central axis. When generating the exterior image 12 as illustrated in FIG. 10, for example, the image data of the inspection position P2 is arranged in a tilted state according to the tilt θ.

Acquiring the inclination θ can improve the accuracy of generating the appearance image 12. This is particularly advantageous when estimating the extent of the soiled portion 11. For example, it can accurately determine whether the soiled portion 11 shown at inspection position P2 is connected to the soiled portion 11 shown at inspection position P20. In the complementation step S5a, it can improve the accuracy of estimating the extent of the soiled portion 11 in the range of the appearance image 12 for which no image data has been acquired.

If a gyroscope or acceleration sensor is installed in the underwater device 2, the tilt φ of the underwater device 2 with the vertical direction z as the central axis can also be detected. When tilt φ occurs in the underwater device 2, the camera 4 captures an image of a position shifted to the left or right with the vertical direction z as the central axis. By acquiring the tilt φ, the captured range can be reflected in the external image 12, as shown in region R1 of the inspection position P20 in Figure 10. This can further improve the accuracy when generating the external image 12. The attitude detection mechanism 18 may be composed of a combination of multiple devices as described above.

When the attitude detection mechanism 18 is composed of an acceleration sensor, this acceleration sensor can detect the position of the underwater device 2 in the horizontal direction and the vertical direction z. In other words, this attitude detection mechanism 18 also functions as a position detection mechanism 6.

11 and 12, the camera 4 may be configured as a camera that captures images of at least 360° in the horizontal direction. The camera 4 may be configured as, for example, a hemispherical camera capable of capturing images of 360° in the horizontal direction, or a 360° spherical camera capable of capturing images of 360° in the horizontal direction and the vertical direction. In this case, the inspection device 1 is equipped with an attitude detection mechanism 18 that detects the inclination φ of the underwater device 2 with the vertical direction z as the central axis. In FIG. 12, the front direction of the underwater device 2, which is provided for convenience of explanation, is indicated by an arrow F. The angle between the perpendicular line extending from the outer wall surface 10b in the width direction x and the front direction F of the underwater device 2 is the inclination φ of the underwater device 2. For example, when the front direction F of the underwater device 2 faces downward in FIG. 12, the inclination φ is 90°, when it faces leftward in FIG. 12, the inclination φ is 180°, and when it faces upward in FIG. 12, the inclination φ is 270°.

Here, we will explain an example in which the underwater device 2, with the forward direction F facing the outer wall surface 10b, descends while rotating clockwise in Figure 12. As illustrated in Figure 13, the camera 4 of the underwater device 2 captures 360° horizontally. On the left side of Figure 13, for convenience, the 360° image is displayed on a plane cut out at a position corresponding to the forward direction F. The water depth and the angle corresponding to the inclination φ of the underwater device 2 are added as position information to the image data in Figure 13. For explanation purposes, the symbol F is displayed in the image data on the left side of Figure 13 at a position corresponding to the forward direction F.

According to the image data of FIG. 13, at a water depth of 0 m, the front direction F faces the outer wall surface 10b, and the outer wall surface 10b is included in the position corresponding to the front direction F in the image. In FIG. 13, for the purpose of explanation, the range in which the outer wall surface 10b is included in the image is indicated by diagonal lines. At a water depth of 5 m, the inclination φ=90°, and the front direction F of the underwater device 2 faces downward in FIG. 12. At this time, the outer wall surface 10b is located to the left of the front direction F. At a water depth of 10 m, the inclination φ=180°, and the front direction F of the underwater device 2 faces left in FIG. 13. At this time, the outer wall surface 10b is located on the opposite side of the front direction F in the image. At a water depth of 15 m, the inclination φ=270°, and the front direction F of the underwater device 2 faces upward in FIG. 13. At this time, the outer wall surface 10b is located to the right of the front direction F in the image. Because the underwater device 2 rotates clockwise while descending, the position in the image data that includes the outer wall surface 10b moves from the front direction F to the left in accordance with the rotation of the underwater device 2.

In acquisition step S3, the processing mechanism 3 acquires the value of the tilt φ from the attitude detection mechanism 18 along with position information in the up-down direction z of the underwater device 2. The processing mechanism 3 extracts the portion corresponding to the outer wall surface 10b from the 360° image shown in FIG. 13, and stitches the images together as shown on the right side of FIG. 13. As shown on the right side of FIG. 13, image data is acquired that is similar to that obtained when an image is taken along the outer wall surface 10b from the water surface (depth 0 m) to the bottom of the vessel (depth 15 m). This image data is handled by the processing mechanism 3 as data for one image, such as inspection position P3. This image data may be used to generate an exterior image 12.

The configuration includes an attitude detection mechanism 18 that acquires the tilt φ and a hemispherical camera, allowing for accurate acquisition of images of the exterior wall surface 10b. In the inspection device 1, the guide mechanism 13 can be simplified to a single wire 14, or a configuration without a guide mechanism 13 can be adopted. A configuration without or with a simplified guide mechanism 13 makes it easier to move the guide mechanism 13 from one inspection position P to another inspection position P. This is advantageous for shortening the inspection time.

The underwater device 2 may have a configuration that involves rotation around the vertical direction z as the central axis when moving along the vertical direction z. That is, in the photographing step S2, the underwater device 2 is actively rotated. For example, a propeller whose rotation is restricted is installed at the lower end or upper end of the main body 2a of the underwater device 2. The propeller receives the water current as the underwater device 2 descends, and the underwater device 2 descends while rotating clockwise or counterclockwise around the vertical direction z as the central axis. A configuration that actively rotates the underwater device 2 can improve the straightness of the underwater device 2 moving along the vertical direction z. The underwater device 2 is less susceptible to the effects of tides, etc.

As shown in Figs. 14 and 15, the underwater device 2 may have a case 19 that is cylindrical with its central axis in the vertical direction z, with the camera 4 located at the center O. The periphery of the case 19 is made of a transparent material such as acrylic resin or glass. The upper and lower surfaces of the case 19 are covered with a material that constitutes the main body 2a of the underwater device 2. In this embodiment, the camera 4 is made of the semi-spherical camera or omnidirectional camera described above.

As shown in FIG. 15, in a plan view, the distance d2 from the center O of the case 19 to the periphery of the case 19 is set to be at least twice the distance d1 from the center O of the case 19 to the end of the camera 4. In other words, the case 19 is formed significantly larger than the camera 4. In the embodiment shown in FIG. 15, the distance d2 is set to eight times the distance d1. The distance d2, which is the radius of the case 19, can be set appropriately within a range that satisfies d1*2≦d2≦d1*20. The inside of the case 19 is filled with a transparent gas such as air, or a transparent liquid such as distilled water. The case 19 is airtight or watertight.

The image is usually taken with seawater or the like passing between the camera 4 and the exterior wall surface 10b, which is the subject of the image. In some cases, the image of the exterior wall surface 10b taken is difficult to grasp the state of contamination due to the influence of turbidity of seawater or the like. The configuration including the case 19 reduces the amount of seawater or the like present between the camera 4 and the exterior wall surface 10b. For the purpose of explanation, in Figure 15, the shooting range of the camera 4 is surrounded by straight lines, and the parts where seawater or the like is present are inked. The inside of the case 19 is filled with a transparent fluid, so the image can be taken with the influence of seawater or the like suppressed. This is advantageous for taking a clear image of the exterior wall surface 10b.

As shown in FIG. 16, in an underwater device 2 having a camera 4 whose shooting range is limited to one direction, rather than a hemispherical or omnidirectional camera, the underwater device 2 may have a bulge 20 that protrudes horizontally in the shooting direction of the camera 4. This bulge 20 is filled with a transparent fluid, similar to the case 19 described above, and is airtight or watertight.

In this embodiment, the bulge 20 is formed in a truncated cone shape. The bulge 20 is installed on the camera 4 with the central axis of the bulge 20 coinciding with the shooting direction of the camera 4. The size of the bulge 20 is set so as to include the shooting range of the camera 4 inside. It is also desirable to set the length of the bulge 20 to a length that occupies 20% or more of the distance from the camera 4 to the outer wall surface 10b in the horizontal direction. The shape of the bulge 20 is not limited to the above. The bulge 20 may be formed in a truncated pyramid shape, or in a cylindrical or prismatic shape.

As shown in FIG. 17, the underwater device 2 may have a case 19 in which the camera 4 is disposed, and a mirror 21 disposed inside the case 19 at a position corresponding to the shooting direction of the camera 4. In this embodiment, the shooting direction of the camera 4 is downward in the vertical direction z, the camera 4 is disposed near the upper end of the case 19, and the mirror 21 is disposed near the lower end of the case 19. The mirror 21 is fixed to the case 19 in a state inclined toward the outer wall surface 10b, and the camera 4 acquires images via the mirror 21.

The camera 4 in this embodiment only needs to have a configuration that acquires an image of the outer wall surface 10b via the gas or liquid filled in the case 19 and the mirror 21. Therefore, the camera 4 is not limited to being placed inside the case 19, and may be placed outside the case 19. For example, when the camera 4 is placed above the case 19, the case 19 is placed below in the shooting direction of the camera 4. The mirror 21 may also be placed outside the case 19. For example, the mirror 21 is placed below the case 19. Either the camera 4 or the mirror 21 may be placed inside the case 19, or both may be placed outside the case 19.

Because the camera 4 photographs the exterior wall surface 10b through the mirror 21, the optical distance from the camera 4 to the exterior wall surface 10b can be increased even if the physical distance of the camera 4 to the exterior wall surface 10b is reduced. Therefore, a relatively wide range of the exterior wall surface 10b can be photographed by the camera 4 while the underwater device 2 is brought closer to the exterior wall surface 10b. Here, the optical distance refers to the distance of the path that the light reflected by the exterior wall surface 10b takes to reach the camera 4. Since the focal plane on which the camera 4 focuses is farther away from the camera 4, the focal range is wider. Since the depth of field is deeper, the camera 4 can easily obtain a focused image even when the distance between the camera 4 and the exterior wall surface 10b changes or when the exterior wall surface 10b is curved or uneven. This is advantageous for obtaining a clear image of the exterior wall surface 10b.

As shown in Figures 18 and 19, the main body 2a of the underwater device 2 is formed, for example, in the shape of a rectangular prism. The case 19 is entirely disposed inside the main body 2a. The case 19 is formed, for example, in the shape of a trapezoidal prism. The main body 2a and the case 19 are configured so that their length in the width direction x is smaller than their lengths in the length direction y and the vertical direction z. It can also be said that the underwater device 2 is configured so that it is thin in the width direction x.

At least a part of the wall of the case 19 is made of a transparent material. The wall in the range where the light reaches the camera 4 from the outer wall surface 10b via the mirror 21 passes through is made of at least a transparent material. When the camera 4 is placed outside the case 19, the part where the camera 4 looks into the inside of the case 19 is made of a transparent material. The other parts may be made of a transparent material or a material that does not transmit light. The inside of the case 19 is filled with a transparent gas or a transparent liquid. Similarly, the wall of the main body 2a in the range where the light reaches the mirror 21 from the outer wall surface 10b passes through is made of at least a transparent material. The other parts of the wall of the main body 2a may be made of a transparent material or a material that does not transmit light. In FIG. 19, the shooting range of the camera 4 is surrounded by straight lines for the purpose of explanation, and the parts where seawater, etc. are present are inked.

The underwater device 2 may have a plurality of wheels 22 installed on the wall surface of the main body 2a, which is one end side of the width direction x. The wheels 22 are configured to be able to roll with the longitudinal direction y as the axial direction. The underwater device 2 may have one or a plurality of lights 7 installed on the wall surface on which the wheels 22 are installed. The underwater device 2 may have a thruster 7 installed on the main body 2a. The thruster 7 is composed of, for example, a cylindrical member that penetrates the main body 2a in the width direction, and a propeller that is arranged inside the member and has the axial direction in the width direction x. The thruster 7 generates a force on the underwater device 2 in the direction in which the wheels 22 are installed. The axial direction of the thruster 7 is not limited to a direction parallel to the width direction x. The axial direction of the thruster 7 may be set to a direction inclined at a predetermined angle in the vertical direction z or the longitudinal direction y with respect to the width direction x.

The case 19 may have a diaphragm 23 fixed to the wall surface that constitutes the case 19. This diaphragm 23 has the function of adjusting the pressure difference between the inside and outside of the case 19. The diaphragm 23 can suppress the pressure difference between the inside and outside of the case 19, which is advantageous in avoiding the problem of the case 19 being damaged by force generated in the case 19. The diaphragm 23 may be installed in the case 19 of the embodiment illustrated in FIG. 14. The same effect as above can be obtained with the embodiment illustrated in FIG. 14.

When the underwater device 2 is dropped into the water, the thrusters 7 press the underwater device 2 against the outer wall surface 10b. When the wheels 22 are rotated by a motor or the like, the wheels 22 roll while maintaining contact with the outer wall surface 10b. The underwater device 2 photographs the outer wall surface 10b while moving downward. When the underwater device 2 reaches the bottom of the vessel 10c, the thrusters 7 are stopped and the device is pulled up to the surface of the water by the cable 5 or the like.

The wheels 22 may be installed on the main body 2a in a passively rotatable state. In this case, the wheels 22 do not have a motor or other power source. The underwater device 2 is pressed against the outer wall surface 10b by the thrusters 7 and descends under its own weight while maintaining contact between the wheels 22 and the outer wall surface 10b. The axial direction of the thrusters 7 may be inclined upward in the vertical direction z, and the underwater device 2 may obtain a downward propulsive force from the thrusters 7.

By configuring the exterior wall surface 10b to be photographed through the mirror 21, the optical distance from the camera 4 to the exterior wall surface 10b can be increased even if the physical distance of the camera 4 to the exterior wall surface 10b is reduced. The underwater device 2 can be made smaller in the width direction x, and the optical distance from the camera 4 to the exterior wall surface 10b can be increased.

Because the size of the underwater device 2 can be reduced in the width direction x, it becomes easier to prevent the underwater device 2 from being swept away in the length direction y due to the influence of tides, etc. Since it becomes difficult for the underwater device 2 to move in the length direction y, it is advantageous to move the underwater device 2 in the up-down direction z.

The configuration in which the thruster 7 presses the underwater device 2 against the outer wall surface 10b makes it easier to maintain a constant optical distance between the outer wall surface 10b and the camera 4. Even if the outer wall surface 10b is relatively curved, such as near the bow or stern of the ship 10, both the physical distance and the optical distance between the outer wall surface 10b and the camera 4 can be maintained constant while taking pictures. The underwater device 2 can easily obtain clear images of the outer wall surface 10b.

1 Inspection device 2 Underwater equipment 2a Main body 2b Auxiliary structure 2c Arm 3 Processing mechanism 4 Camera 5 Cable 6 Position detection mechanism 7 Thruster 8 Ballast tank 9 Lighting 10 Ship 10a Upper deck 10b Outer wall surface 10c Ship bottom 11 Contaminated part 12 External image 13 Guide mechanism 14 Wire 15 Weight 16 Support mechanism 17 Connector 18 Attitude detection mechanism 19 Case 20 Bulge 21 Mirror 22 Wheel 23 Diaphragm P Inspection position S1 Horizontal position selection step S2 Photography step S3 Acquisition step S4 Judgment step S5 External image generation step S5a Complement step S6 Contamination state judgment step F (of underwater equipment) Front direction d1, d2 Distance x Width direction y Length direction z Up-down direction

Claims (10)

In a method for inspecting the fouling condition of the exterior wall of a ship,
The system includes an underwater device having a camera and a processing mechanism for acquiring data from the underwater device,
The underwater device has a mirror disposed at a position in the shooting direction of the camera, and a case having at least a part of a wall surface made of a transparent material and filled with a transparent gas or liquid, and is configured such that an optical distance from the camera to the mirror is set to be greater than an optical distance from the mirror to the outer wall surface,
a horizontal position selection step of selecting one inspection position within a range from the bow to the stern of the ship;
an imaging step in which the underwater device having the camera is moved in a vertical direction at the inspection position selected in the horizontal position selection step, and the camera acquires an image of the outer wall surface through the gas or liquid filled in the case and the mirror ;
and an acquisition step in which the processing mechanism acquires data from the underwater device,
An inspection method, comprising the steps of: selecting the horizontal position; photographing the image; and acquiring the image. The camera has a configuration in which an image capturing direction faces downward in the up-down direction and is disposed near an upper end of the case,
2. The inspection method according to claim 1, wherein the mirror is disposed near a lower end of the case. The underwater device has a main body formed in a rectangular prism shape and the entire case is disposed inside the main body,
An inspection method as described in claim 1 or 2, wherein the main body and the case are configured so that their widthwise length, which is perpendicular to the longitudinal direction, is smaller than their length in the longitudinal direction connecting the bow and stern of the ship and in the vertical direction. The acquiring step includes a configuration in which the processing mechanism acquires image data acquired by the camera and position information of the underwater device corresponding to the image data,
The processing mechanism includes an exterior image generating step of generating an exterior image in which a plurality of the images are arranged on a virtual exterior wall surface based on the data acquired in the acquiring step,
The inspection method according to claim 1 or 2, wherein the external image generating step has a configuration in which the external image is generated by adjusting the vertical position of each of the images of the exterior wall surface and combining them. The inspection method described in claim 4, wherein the exterior image generation step is configured to generate the exterior image by adjusting the relative longitudinal positions of each of the images of the exterior wall surfaces in a longitudinal direction that is a direction connecting the bow and stern of the ship, and combining them. In an inspection device for inspecting the fouling condition of the exterior wall of a ship,
The device includes an underwater device having a camera and a processing mechanism for acquiring data from the underwater device,
The underwater device has a mirror arranged at a position in the shooting direction of the camera, and a case having at least a part of a wall surface made of a transparent material and filled with a transparent gas or liquid, and has a configuration in which an optical distance from the camera to the mirror is set to be longer than an optical distance from the mirror to the outer wall surface,
the camera has a configuration for acquiring an image of the exterior wall surface via the gas or liquid filled in the case and the mirror,
The inspection apparatus is characterized in that the underwater equipment acquires images of the outer wall surface while moving in a vertical direction. The camera has a configuration in which an image capturing direction faces downward in the up-down direction and is disposed near an upper end of the case,
The inspection device according to claim 6 , wherein the mirror is disposed near a bottom end of the case. The underwater device has a main body formed in a rectangular prism shape and the entire case is disposed inside the main body,
An inspection device as described in claim 6 or 7, wherein the main body and the case are configured so that their widthwise length, which is perpendicular to the longitudinal direction, is smaller than their lengths in the longitudinal direction connecting the bow and stern of the ship and in the vertical direction. A position detection mechanism is provided for acquiring vertical position information corresponding to the data of the image of the exterior wall surface,
8. The inspection device according to claim 6, wherein the processing mechanism is configured to adjust the vertical position of each of the images of the exterior wall surface and combine them to generate an exterior image. The inspection device described in claim 9, wherein the processing mechanism is configured to generate the appearance image by adjusting the relative longitudinal positions of each of the images of the exterior wall surface in a longitudinal direction that is the direction connecting the bow and stern of the ship, and combining them.

Images