Inspection method and inspection apparatus

Abstract

To provide in inspection method and an inspection device capable of efficiently inspecting a contaminated state of an outer wall surface of a ship.SOLUTION: An inspection method for inspecting contaminated state of an outer wall surface 10b of a ship 10 includes: a horizontal position selection step of selecting one inspection position P in a range from a bow to a stern of the ship 10; an imaging step of acquiring images of the outer wall surface 10b while moving underwater equipment 2 having a camera along a vertical direction z at the inspection position P selected in the horizontal position selection step; and an acquisition step of acquiring, by a processing mechanism, data from the underwater equipment 2. Therein, the horizontal position selection step, the imaging step, and the acquisition step are repeatedly executed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an inspection method and an inspection apparatus for inspecting the fouling condition of the outer wall surface of a ship, and more particularly to an inspection method and an inspection apparatus capable of efficiently inspecting the fouling condition of the outer wall surface of a ship.

Background Art

[0002] In recent years, it has been required to prevent the movement of marine organisms such as algae and shellfish attached to ships. It is desirable to be able to confirm the presence or absence of fouling of the ship by algae or the like before entering the port. In order to grasp the fouling condition of the ship before entering the port and determine whether to enter the port, it is necessary to efficiently grasp the overall fouling condition of the ship in a relatively short time. Various underwater robots have been proposed for inspecting the fouling condition of the outer wall surface of a ship (see, for example, Patent Document 1). Patent Document 1 discloses the configuration of an underwater robot that moves along the outer wall surface and acquires data indicating the condition of the outer wall surface with a sensor or the like.

[0003] Since the underwater robot of Patent Document 1 is very small compared to the size of the outer wall surface of the ship, it has taken a great deal of time to inspect the entire ship. Also, when the water is turbid, if trying to take a picture from a distance, the outer wall surface of the ship cannot be seen due to the turbidity of the water. It is necessary to bring the camera of the underwater robot close to the outer wall surface of the ship, and the range of the image that can be acquired by the camera of the underwater robot becomes small. Therefore, it has been extremely difficult to grasp which position of the ship the image acquired by the camera corresponds to. Furthermore, since the underwater robot of Patent Document 1 is premised on use on a ship in navigation, it cannot be used for inspecting a ship at anchor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide an inspection method and an inspection apparatus capable of efficiently inspecting the fouling condition of the outer wall surface of a ship.

Means for Solving the Problems

[0006] An inspection method for achieving the above object is an inspection method for inspecting the fouling condition of the outer wall surface of a ship, An underwater device having a camera and a processing mechanism for acquiring data from the underwater device are provided in advance. The underwater device has a mirror disposed at a position in the shooting direction of the camera, and a case in which at least a part of the wall surface is made of a transparent member and filled with a transparent gas or liquid inside. The optical distance from the camera to the mirror is set to be larger than the optical distance from the mirror to the outer wall surface in advance. a horizontal position selection step of selecting one inspection position in the range from the bow to the stern of the ship, and at the inspection position selected in the horizontal position selection step The while moving an underwater device having a camera The vertically, The camera acquires an image of the outer wall surface through the gas or liquid filled in the case and the mirror. a photographing step of acquiring an image of the outer wall surface, The and an acquisition step of a processing mechanism acquiring data from the underwater device, characterized in that the horizontal position selection step, the photographing step, and the acquisition step are repeatedly executed.

[0007] An inspection apparatus for achieving the above object is an inspection apparatus for inspecting the fouling condition of the outer wall surface of a ship, comprising 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 in which at least a part of the wall surface is made of a transparent member and filled with a transparent gas or liquid inside. The optical distance from the camera to the mirror is set to be larger than the optical distance from the mirror to the outer wall surface. The camera has a configuration for acquiring an image of the outer wall surface through the gas or liquid filled in the case and the mirror. wherein the underwater device is characterized in that it acquires an image of the outer wall surface while moving vertically.

Effects of the Invention

[0008] According to the present invention, it is possible to grasp the overall fouling condition of the outer wall surface of a ship by acquiring images along the vertical direction at a plurality of inspection positions in the direction from the bow to the stern of the ship. This is advantageous for efficiently inspecting the fouling condition of the outer wall surface of a ship.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, the inspection method and inspection apparatus will be described based on the embodiments shown in the drawings. In the drawings, 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 intersects the length direction y at a right angle, is indicated by arrow x, and the vertical direction is indicated by arrow z.

[0011] As illustrated in FIG. 1, the inspection apparatus 1 includes an underwater device 2 and a processing mechanism 3 that acquires data from the underwater device 2. The underwater device 2 has a main body 2a and a camera 4 installed on the main body 2a. The main body 2a is configured, for example, in a cylindrical shape. The main body 2a may have conical members disposed at the upper and lower ends. The camera 4 can acquire at least one of moving images or still images.

[0012] The processing mechanism 3 is connected to the underwater device 2 by a cable 5. The cable 5 is composed of, for example, a signal line that sends data of an image captured by the camera 4 to the processing mechanism 3. The cable 5 may include an electric wire that supplies power from the processing mechanism 3 to the underwater device 2. The processing mechanism 3 can be configured by various known computers. The processing mechanism 3 has a central processing unit (CPU), a main memory unit (memory), and an auxiliary storage unit (e.g., HDD). The processing mechanism 3 may be configured to be installed on the main body 2a of the underwater device 2.

[0013] The underwater device 2 may have a pair of auxiliary structures 2b disposed on both sides with the main body 2a as the center. The auxiliary structures 2b are configured, for example, in a cylindrical shape. The auxiliary structures 2b may have conical members disposed at the upper and lower ends. Each of the auxiliary structures 2b may also have two arm portions 2c disposed between the main body 2a.

[0014] The inspection apparatus 1 may include a position detection mechanism 6 installed, for example, inside the main body 2a. The position detection mechanism 6 is configured to acquire the position information of the underwater device 2 and is composed of, for example, a depth gauge.

[0015] With a configuration having a pair of auxiliary structures 2b, the underwater device 2 can suppress rotation (hereinafter sometimes referred to as skew) about the vertical direction z as the central axis.

[0016] The underwater device 2 may have a plurality of thrusters 7 each constituted by, for example, a propeller connected to a motor. The thrusters 7 are installed, for example, on the main body 2a or the auxiliary structure 2b. With the configuration having the thrusters 7, the underwater device 2 can control its movement in the vertical direction z in water. Also, with the thrusters 7, the underwater device 2 can control its attitude in water. Here, the attitude of the underwater device 2 means the inclination of the underwater device 2 about the width direction x, the length direction y, or the vertical direction z as the central axis.

[0017] The underwater device 2 may have a ballast tank 8 installed, for example, on the auxiliary structure 2b. The ballast tank 8 can control the inflow and outflow of water to and from the outside. With the configuration having the ballast tank 8, it becomes possible to sink the underwater device 2 with water injected into the ballast tank 8 and to float the underwater device 2 by buoyancy by draining the water from the ballast tank 8. The ballast tank 8 may be installed on the main body 2a. By arranging the ballast tanks 8 on the pair of auxiliary structures 2b respectively and controlling the inflow and outflow of water respectively, it also becomes possible to control the attitude of the underwater device 2. The underwater device 2 may be provided with both the thrusters 7 and the ballast tank 8, or may be provided with only one of them.

[0018] The underwater device 2 preferably has a lighting 9 installed, for example, on the main body 2a. With the lighting 9, it becomes possible to take a photograph by the camera 4 even in a relatively deep place where the light quantity is insufficient or at night. The lighting 9 may be installed on the auxiliary structure 2b. A plurality of lightings 9 may be installed on the underwater device 2.

[0019] As illustrated in FIG. 2, in a ship 10 at berth such as a tanker or a container ship, one inspection position P is selected within the range from the bow to the stern of the ship 10 (horizontal position selection step S1). In the case of a ship 10 with a length of 300 m in the longitudinal direction y, for example, the inspection position 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 position P is not limited to the above. The interval between the inspection positions P does not need to be equally spaced. Also, the number of inspection positions P does not need to be 40 in total for both sides. For example, it may be 10 in total for both sides, or may be set to 50 or more. A configuration in which the inspection position P is set only on one side, either the port side or the starboard side, may also be used.

[0020] In the horizontal position selection step S1, one inspection position P, such as the inspection position P3, is selected from the preset inspection positions P.

[0021] Next, the underwater device 2 is lowered from the upper deck 10a of the selected inspection position P3. The underwater device 2 descends into the water by its own weight, for example. While lowering the underwater device 2, the outer wall surface 10b of the ship 10 is photographed (photographing step S2). The underwater device 2 performs photographing while descending along the vertical direction z within the range from the upper deck 10a to the bottom 10c of the ship. After the underwater device 2 is lowered near the bottom 10c, it may be raised while photographing. Also, photographing may be performed both while the underwater device 2 is descending and while it is ascending. The underwater device 2 ascends, for example, by winding the cable 5. The underwater device 2 may be connected to a rope different from the cable 5 and have a configuration in which it ascends by winding this rope. The range photographed by the underwater device 2 is not limited to the range below the water surface. The range above the water surface may also be photographed. In FIG. 2, the damaged portion 11 of the outer wall surface 10b is shown hatched for explanation.

[0022] The inspection device 1 is not limited to a configuration in which it is arranged on the ship 10 for inspection. It may be a configuration in which a small ship on which the inspection device 1 is arranged is approached to the ship 10 to be inspected, and the underwater device 2 is lowered from this small ship for photographing. In this case, the position of the small ship relative to the ship 10 is selected in the horizontal position selection step S1. An operator who performs the inspection can perform the inspection without boarding the ship 10 to be inspected.

[0023] As illustrated in FIG. 3, the processing mechanism 3 acquires data from the underwater device 2 (acquisition step S3). The data acquired by the processing mechanism 3 includes data of images photographed by the camera 4. The image data may be a moving image, a still image, or both. In the case of a moving image, for example, a series of images from the upper deck 10a to the bottom 10c of the ship, or a series of images from the water surface to the bottom 10c of the ship are acquired. In the case of a still image, a plurality of still images are acquired at predetermined intervals in terms of time or the distance in the vertical direction z.

[0024] 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 for distinguishing a plurality of inspection positions P or coordinate data of the inspection position P. It can also be said that the horizontal position information is composed of data indicating the position in the ship 10. In the embodiment of FIG. 3, the number of the inspection position P at which the image data is acquired is included as the horizontal position information. For example, it becomes possible to distinguish the image data corresponding to the inspection position P1 and the image data corresponding to the inspection position P3.

[0025] The data acquired by the processing mechanism 3 may include the 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 in the imaging 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 the configuration 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 to detect the amount of cable 5 paid out. Based on the amount of cable 5 paid out from the upper deck 10a to the underwater device 2, the water depth of the underwater device 2 may be acquired. The position detection mechanism 6 is composed of, for example, a program stored in the processing mechanism 3. Based on this program, the water depth may be estimated based on the speed and time at which the underwater device 2 descends from the water surface. The program may have a configuration that calculates the speed and moving direction of the underwater device 2 from the image acquired by the camera 4 and estimates the position of the underwater device 2.

[0026] 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 the position information in the vertical direction z corresponding to the image data. In addition to this, the position detection mechanism 6 may have a configuration capable of acquiring the position information in the horizontal direction corresponding to the image data. The position detection mechanism 6 is not an essential component of the inspection device 1.

[0027] The position detection mechanism 6 may be configured to acquire horizontal position information. The position detection mechanism 6 may be composed of, for example, a Global Navigation Satellite System (GNSS) antenna installed in the underwater device 2. Also, the position detection mechanism 6 may be composed of a positioning system using ultrasonic waves. The position detection mechanism 6 may be composed of, for example, an acceleration sensor installed in the underwater device 2. The position of the underwater device 2 is estimated from the integration of the change amount of acceleration by the acceleration sensor. These position detection mechanisms 6 can acquire the coordinates of the underwater device 2 in the three-dimensional space as position information. The position information consisting of coordinates in the three-dimensional space includes the vertical direction z and the horizontal position information corresponding to the image data.

[0028] The position detection mechanism 6 may also be composed of a combination of the above-mentioned multiple devices. For example, the position detection mechanism 6 may be composed of GNSS and an ultrasonic positioning system, and the position information may be acquired by GNSS when the underwater device 2 is on the water surface, and the position information may be acquired by the ultrasonic positioning system when it is underwater.

[0029] When the camera 4 is taking a picture in the photographing step S2, the position information may be added to the data of this image and sent to the processing mechanism 3. In this case, the underwater device 2 sends the image data and the position 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 executed simultaneously.

[0030] After the completion of the photographing step S2, the acquisition step S3 may be executed. In this case, after the completion of the photographing step S2, the data is transferred from the underwater device 2 to the processing mechanism 3. When the underwater device 2 is underwater, the data is stored in the storage mechanism installed in the underwater device 2. The inspection device 1 of this embodiment may not have the cable 5.

[0031] While changing the inspection position P from P1 to, for example, P40, the underwater device 2 repeats photographing a plurality of times. That is, the horizontal position selection step S1, the photographing step S2, and the acquisition step S3 are repeatedly executed. A plurality of inspection devices 1 may be used to perform inspections simultaneously. For example, two inspection devices 1 may be used, and one inspection device 1 may inspect the inspection position P1-20 on the port side, and the other inspection device 1 may inspect the inspection position 21-40 on the starboard side.

[0032] From the data of a plurality of images, the fouling condition of the outer wall surface 10b can be evaluated. As illustrated in FIG. 3, the image data shows the condition of the outer wall surface 10b in at least the range from the water surface (water depth 0 m) to the bottom of the ship 10c (water depth 15 m). For example, from the images of the inspection positions P2 and P3, it can be easily imagined that the fouled portion 11 spreads horizontally in the portion with a water depth of about 6 m. Further, from the image of the inspection position P20, since there is a fouled portion 11 in the portion with a water depth of about 10 m, it can be easily imagined that the fouled portion 11 at the inspection position P2 spreads horizontally while shifting downward to the inspection position P20. In FIG. 3, the fouled portion 11 is hatched for explanation. Also, in FIG. 3, the data of the inspection positions P4 to P19 are omitted.

[0033] By acquiring images at a plurality of inspection positions P by the inspection device 1 in the longitudinal direction y from the bow to the stern of the ship 10, it becomes possible to grasp the overall fouling condition of the outer wall surface 10b of the ship 10. Fouling by marine organisms such as algae and shellfish has a property of spreading horizontally. Therefore, by acquiring images along the vertical direction z at a plurality of inspection positions P, it becomes possible to estimate the overall fouling condition of the outer wall surface 10b.

[0034] In the photographing step S2, since the underwater device 2 is configured to move only along the vertical direction z, if the position in the vertical direction z is grasped, the position of the portion shown in the image can be grasped.

[0035] Since the underwater device 2 can move in the vertical direction z without using the water flow, it is possible to inspect the fouling condition of the ship 10 while it is at anchor.

[0036] A configuration may be provided in which a determination step S4 for determining whether shooting has been completed at all preset inspection positions P exemplified in FIG. 4 is executed by the processing mechanism 3. After it is determined in the determination step S4 that there is no next inspection position P, an appearance image generation step S5 for generating an appearance image that reproduces the entire outer wall surface 10b may be executed. The processing mechanism 3 executes the appearance image generation step S5. When the appearance 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.

[0037] As shown in FIG. 5, in the appearance image 12, data of a plurality of images are arranged based on the position information in the horizontal direction and the vertical direction z. In the appearance image generation step S5, for example, the vertical position of each image is adjusted in a state where the position of the water surface (water depth 0 m) and the position of the bottom of the ship 10c (water depth 15 m) match. For example, a plurality of images on the port side are generated as one appearance image 12 with the relative positions in the vertical direction z and the length direction y adjusted. In the appearance image generation step S5, for example, one appearance image 12 is generated on the port side and one appearance image 12 is generated on the starboard side. In FIG. 5, the range of the appearance image 12 is shown by a broken line for explanation purposes. The range inside the broken line is generated as the appearance image 12. The appearance image 12 is displayed, for example, on a monitor connected to the processing mechanism 3. In FIG. 5, the interval between the image data in the length direction y is shown narrowed for explanation purposes. Actually, the range shown by 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.

[0038] Based on this appearance image 12, the fouling condition is determined. As illustrated in FIG. 5, although there are many parts lacking image information in the appearance image 12, it is in a state as if observing the entire outer wall surface 10b. From the appearance image 12, it becomes easy to estimate the spread of the fouled part 11 in the range where the image has not been acquired. In FIG. 5, the range estimated to be the fouled part 11 is indicated by a dashed line for explanation. By generating the appearance image 12, it becomes easy to judge the fouling condition.

[0039] As illustrated in FIG. 4, a configuration may be provided in which a complementary step S5a for estimating the situation in the range where image data cannot be obtained and complementing the appearance image 12 is executed. The processing mechanism 3 executes the complementary step S5a. In the complementary step S5a, for example, the range of the fouled part 11 is estimated and this range is added to the appearance image 12. For example, the dashed line illustrated in FIG. 5 is added to the appearance image 12.

[0040] In the complementary step S5a, the fouled part 11 is extracted from the data of individual images by image processing. For example, the fouled part 11 is extracted by image processing such as binarization processing or edge detection processing. In the data of adjacent images, the boundary lines of the fouled parts 11 with the closest positions in the vertical direction z are connected by a straight line (see the dashed line in FIG. 5). Thereby, the fouled part 11 of the appearance image 12 is complemented. It can be estimated that the range surrounded by the dashed line is the fouled part 11. By displaying the range of the fouled part 11 in the appearance image 12, it becomes easier to grasp the range of the fouled part 11 in the entire outer wall surface 10b.

[0041] A configuration may be provided in which an operator executes the complementary step S5a. The operator looks at the image data and extracts the range of the fouled part 11. The operator adds a boundary line to the range where the fouled part 11 is estimated to spread in the appearance image 12. For example, the operator adds the dashed line illustrated in FIG. 5 to the appearance image 12.

[0042] As illustrated in FIG. 4, it may have a configuration in which a fouling condition determination step S6 for determining the fouling condition from the appearance image 12 is executed. The processing mechanism 3 executes the fouling condition determination step S6. The processing mechanism 3 calculates the ratio (hereinafter sometimes referred to as the fouling degree) of the fouled portion 11 to the outer wall surface 10b in the appearance image 12, and determines the fouling condition based on this fouling degree. The higher the fouling degree, the worse the fouling condition. Specifically, the range from the water surface to the bottom of the ship 10c in the appearance image 12 of FIG. 5 is calculated as the area of the outer wall surface 10b. Also, the area of the fouled portion 11 indicated by the hatching and the estimated range surrounded by the dashed-dotted line is calculated as the range of the fouled portion 11. The fouling degree is calculated from the two areas. That is, the fouling degree is calculated including the range complemented in the complementing step S5a. The range from the upper deck 10a to the bottom of the ship 10c may be calculated as the area of the outer wall surface 10b. In this case, the upper deck 10a needs to be included in the data of each image.

[0043] By performing an inspection before entering the port, when the fouling degree exceeds a preset threshold value such as 10%, it is possible to take measures such as rejecting entry into the port. Also, when inspecting the ship, the necessity of cleaning the outer wall surface 10b may be determined according to the fouling degree. With the configuration for calculating the fouling degree, it becomes possible to quantitatively evaluate the fouling condition of the outer wall surface 10b of the ship 10.

[0044] The method for calculating the fouling degree is not limited to the above. It is sufficient to have a configuration capable of quantitatively evaluating the spread of the fouled portion 11. For example, it may have a configuration for calculating the fouling degree without including the complemented range. Specifically, the range from the water surface to the bottom of the ship 10c in the image data of FIG. 5 is calculated as the area of the outer wall surface 10b. Also, the area of the fouled portion 11 indicated by the hatching is calculated. The fouling degree is calculated from the two areas. Even when the inspection method does not have the appearance image generation step S5 or the complementing step S5a, the fouling degree can be calculated by the above method.

[0045] It may have a configuration in which an operator executes the fouling condition determination step S6. The operator may check the appearance image 12 or the data of a plurality of images, and calculate and evaluate the fouling degree based on these.

[0046] As illustrated in FIG. 6, the inspection device 1 may include a guide mechanism 13 that extends in the vertical direction z and is disposed in the vicinity of the outer wall surface 10b. In this embodiment, the guide mechanism 13 has a single wire 14 stretched in the vertical direction z and a weight 15 disposed 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 ship 10c.

[0047] The guide mechanism 13 may have a support mechanism 16 for suspending the wire 14 from the upper deck 10a. The support mechanism 16 projects seaward from the upper deck 10a. The support mechanism 16 holds the wire 14 at a position, for example, 1 m seaward from the outer wall surface 10b. Further, the support mechanism 16 is 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 in accordance with a preset inspection position P.

[0048] As illustrated in FIG. 7, the underwater device 2 is connected to the wire 14 via a pair of connectors 17 arranged at intervals 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. Since the underwater device 2 is connected to the wire 14 by a pair of connectors 17, rotation of the underwater device 2 about the length direction y or the width direction x as the central axis can be suppressed. In this embodiment, the underwater device 2 does not have an auxiliary structure 2b.

[0049] As illustrated in FIGS. 6 and 7, with the configuration including the guide mechanism 13, it is possible to suppress a problem that the underwater device 2 moves unintentionally in the horizontal direction (length direction y and width direction x). Since the underwater device 2 can descend or ascend substantially straight along the outer wall surface 10b, the accuracy of the position information corresponding to the image data can be improved.

[0050] As illustrated 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 wire 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. Since 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 can be suppressed in addition to the length direction y and the width direction x. The underwater device 2 can photograph the outer wall surface 10b straight on from the front. The accuracy of the position information corresponding to the image data can be further improved.

[0051] The configuration of the guide mechanism 13 is not limited to the above. The guide mechanism 13 may be configured by a rail that is less likely to deform than a wire. The rail is made of a steel material such as a rolled steel material extending in the vertical direction z. At this time, a weight may or may not be disposed near the lower end of the rail. This is advantageous for suppressing rotation of the underwater device 2 about the length direction y, the width direction x, and the vertical direction z. Further, compared to a wire, the rail is less likely to deform and has a large weight, so it is less affected by tidal currents and wind. This is advantageous for lowering the underwater device 2 straight down parallel to the vertical direction z.

[0052] The underwater device 2 may be configured to move using a drive mechanism such as wheels with respect to the rail constituting the guide mechanism 13. For example, a rack is formed on the rail, and a pinion gear is disposed on the underwater device 2. This is advantageous for accurately controlling the moving speed of the underwater device 2 in the vertical direction z.

[0053] As illustrated in FIG. 9, the inspection device 1 may include an attitude detection mechanism 18 that detects the inclination of the underwater device 2 or the guide mechanism 13. The attitude detection mechanism 18 is configured, for example, by an inclinometer installed on the support mechanism 16 to detect the inclination θ of the wire 14 with respect 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.

[0054] The attitude detection mechanism 18 is composed of, for example, an inclinometer, a gyroscope, an acceleration sensor, or an optical gyro installed in the underwater device 2 to detect the inclination θ of the underwater device 2 with respect 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 the acquisition step S3, the processing mechanism 3 acquires the value of the inclination θ from the attitude detection mechanism 18 in the same way as the position information of the underwater device 2.

[0055] With the configuration in which the inspection device 1 is equipped with the attitude detection mechanism 18, the inclination θ with respect to the vertical direction z of the image captured by the underwater device 2 can be obtained. The inclination θ indicates the inclination of the underwater device 2 with the width direction x as the central axis. When generating the external appearance image 12 as illustrated in FIG. 10, for example, the image data of the inspection position P2 is arranged in a state tilted according to the inclination θ.

[0056] By obtaining the inclination θ, the accuracy in generating the external appearance image 12 can be improved. This is particularly advantageous when estimating the range of the damaged portion 11. For example, it is possible to accurately determine whether or not the damaged portion 11 shown at the inspection position P2 is connected to the damaged portion 11 shown at the inspection position P20. In the complement step S5a, the accuracy in estimating the spread of the damaged portion 11 in the range of the external appearance image 12 where the image data has not been acquired can be improved.

[0057] When a gyroscope or an acceleration sensor is installed in the underwater device 2, the inclination φ of the underwater device 2 with the vertical direction z as the central axis can also be detected. When the inclination φ occurs in the underwater device 2, the camera 4 captures an image at a position shifted leftward or rightward with the vertical direction z as the central axis. By obtaining the inclination φ, as shown in the region R1 of the inspection position P20 in FIG. 10, the captured range can be reflected in the external appearance image 12. The accuracy in generating the external appearance image 12 can be further improved. The attitude detection mechanism 18 may be composed of a combination of the above-mentioned plurality of devices.

[0058] When the posture detection mechanism 18 is composed of an acceleration sensor, it becomes possible to detect the position of the underwater device 2 in the horizontal direction and the vertical direction z with this acceleration sensor. That is, this posture detection mechanism 18 also has the function as a position detection mechanism 6.

[0059] As illustrated in FIGS. 11 and 12, the camera 4 may be composed of a camera that acquires an image of at least 360° in the horizontal direction. The camera 4 is composed of, for example, a hemispherical camera capable of shooting 360° in the horizontal direction or an omnidirectional camera capable of shooting 360° in the horizontal direction and the vertical direction. In this case, the inspection device 1 includes a posture 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 provided for convenience of explanation is indicated by an arrow F. The angle formed by the perpendicular line extending in the width direction x from the outer wall surface 10b 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 = 90°, when it faces left in FIG. 12, φ = 180°, and when it faces upward in FIG. 12, the inclination φ = 270°.

[0060] Here, a case where the underwater device 2 in a state where the front direction F faces the outer wall surface 10b descends while rotating clockwise in FIG. 12 will be described as an example. As illustrated in FIG. 13, the camera 4 of the underwater device 2 is shooting 360° in the horizontal direction. On the left side of FIG. 13, the 360° image is displayed on a plane cut open at a position corresponding to the front direction F for convenience. Depth information and the angle corresponding to the inclination φ of the underwater device 2 are added as position information to the image data in FIG. 13. For the sake of explanation, on the left side of FIG. 13, the symbol F is displayed at the position corresponding to the front direction F in the image data.

[0061] According to the data of the image in Fig. 13, at a water depth of 0 m, the front direction F is in a state facing the outer wall surface 10b directly, and the outer wall surface 10b is included at the position corresponding to the front direction F in the image. In Fig. 13, the range in which the outer wall surface 10b is included in the image is shown by hatching for explanation. 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 on the left side 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 leftward in Fig. 13. At this time, in the image, the outer wall surface 10b is located on the opposite side of the front direction F. 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, in the image, the outer wall surface 10b is located on the right side of the front direction F. Since the underwater device 2 is descending while rotating clockwise, the position where the outer wall surface 10b is included in the image data moves leftward from the front direction F in accordance with the rotation of the underwater device 2.

[0062] The processing mechanism 3 acquires the value of the inclination φ from the attitude detection mechanism 18 together with the position information of the underwater device 2 in the vertical direction z in the acquisition step S3. The processing mechanism 3 extracts the portion corresponding to the outer wall surface 10b from the 360° image shown in Fig. 13 and joins the images as shown on the right side of Fig. 13. As shown on the right side of Fig. 13, image data similar to the case of photographing along the outer wall surface 10b from the water surface (water depth 0 m) to the bottom of the ship (water depth 15 m) is acquired. This image data is handled by the processing mechanism 3 as the data of one image, such as the inspection position P3. The external appearance image 12 may be generated using this image data.

[0063] With a configuration having the attitude detection mechanism 18 for acquiring the inclination φ and the hemispherical camera, an image of the outer wall surface 10b can be acquired with high accuracy. In the inspection device 1, the guide mechanism 13 can be simplified as a single wire 14, or a configuration without the guide mechanism 13 can be adopted. With a configuration without or simplified guide mechanism 13, the movement of the guide mechanism 13 from one inspection position P to another inspection position P becomes easy. This is advantageous for shortening the inspection time.

[0064] When the underwater device 2 moves along the vertical direction z, it may have a configuration involving rotation about the vertical direction z as the central axis. That is, in the imaging 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. When the underwater device 2 descends, the propeller receives the water flow, and the underwater device 2 descends while rotating clockwise or counterclockwise about the vertical direction z as the central axis. By the configuration of actively rotating the underwater device 2, the straightness of the underwater device 2 moving along the vertical direction z can be improved. The underwater device 2 is less likely to be affected by tidal currents or the like.

[0065] As illustrated in FIGS. 14 and 15, the underwater device 2 may have a case 19 configured in a cylindrical shape with the vertical direction z as the central axis, and a camera 4 is disposed at the center O. The peripheral surface of the case 19 is formed of a transparent member such as acrylic resin or glass. The upper and lower surfaces of the case 19 are covered with members constituting the main body 2a of the underwater device 2. In this embodiment, the camera 4 is composed of the above-described hemispherical camera or omnidirectional camera.

[0066] As illustrated in FIG. 15, in plan view, the distance d2 from the center O of the case 19 to the peripheral surface of the case 19 is set to be twice or more the distance d1 from the center O of the case 19 to the end of the camera 4. That is, the case 19 is formed to be significantly larger than the camera 4. In the embodiment illustrated in FIG. 15, the distance d2 is set to be eight times the distance d1. The distance d2, which is the radius of the case 19, can be appropriately set within the range satisfying d1*2≦d2≦d1*20. Further, 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 has airtightness or watertightness.

[0067] Normally, the photographing is performed with seawater or the like intervening from the camera 4 to the outer wall surface 10b which is the object of photographing. In some cases, it may be difficult to grasp the fouling condition from the image of the photographed outer wall surface 10b due to the influence of turbidity of seawater or the like. With the configuration including the case 19, the amount of seawater or the like existing between the camera 4 and the outer wall surface 10b is reduced. In FIG. 15, for the sake of explanation, the photographing range of the camera 4 is surrounded by a straight line, and the portions where seawater or the like exists are shaded. Since the inside of the case 19 is filled with a transparent fluid, an image can be acquired in a state where the influence of seawater or the like is suppressed. This is advantageous for acquiring a clear image of the outer wall surface 10b.

[0068] As illustrated in FIG. 16, in the underwater device 2 having the camera 4 whose photographing range is limited in one direction, rather than a hemispherical camera or an omnidirectional camera, the underwater device 2 may have a bulging portion 20 projecting in the horizontal direction which is the photographing direction of the camera 4. This bulging portion 20 is filled with a transparent fluid in the same manner as the aforementioned case 19 and has airtightness or watertightness.

[0069] In this embodiment, the bulging portion 20 is formed in a frustum of a cone shape. The bulging portion 20 is installed on the camera 4 in a state where the central axis of the bulging portion 20 coincides with the photographing direction of the camera 4. Also, the size of the bulging portion 20 is set in a state of including the inside of the photographing range of the camera 4. Further, it is desirable that the length of the bulging portion 20 be set to a length occupying 20% or more of the distance from the camera 4 to the outer wall surface 10b in the horizontal direction. The shape of the bulging portion 20 is not limited to the above. The bulging portion 20 may be formed in a frustum of a pyramid shape, or may be formed in a cylindrical shape or a prismatic shape.

[0070] As illustrated in FIG. 17, the underwater device 2 may have a case 19 in which the camera 4 is disposed inside, and a mirror 21 disposed inside the case 19 at a position in the photographing direction of the camera 4. In this embodiment, the photographing 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 of being inclined in the direction of the outer wall surface 10b, and the camera 4 acquires an image through the mirror 21.

[0071] The camera 4 of this embodiment only needs to be configured to acquire 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 disposed inside the case 19, and may be disposed outside the case 19. For example, when the camera 4 is disposed above the case 19, the case 19 is disposed below in the shooting direction of the camera 4. Also, the mirror 21 may be disposed outside the case 19. For example, the mirror 21 is disposed below the case 19. Either one of the camera 4 and the mirror 21 may be disposed inside the case 19, or both may be disposed outside the case 19.

[0072] Since the camera 4 shoots the outer wall surface 10b via the mirror 21, even if the physical distance between the camera 4 and the outer wall surface 10b is reduced, the optical distance from the camera 4 to the outer wall surface 10b can be increased. Therefore, while approaching the underwater device 2 to the outer wall surface 10b, the camera 4 can shoot a relatively wide range of the outer wall surface 10b. Here, the optical distance refers to the distance of the path until the light reflected by the outer wall surface 10b reaches the camera 4. Since the in-focus plane where the camera 4 is in focus is farther from the camera 4, the in-focus range becomes wider. Since the depth of field is deeper, the camera 4 can easily acquire a focused image even with respect to a change in the distance between the camera 4 and the outer wall surface 10b, or the curvature or unevenness of the outer wall surface 10b. This is advantageous for obtaining a clear image of the outer wall surface 10b.

[0073] As illustrated in FIGS. 18 and 19, the main body 2a of the underwater device 2 is formed, for example, in a quadrangular prism shape. The case 19 is entirely disposed inside the main body 2a. The case 19 is formed, for example, in a trapezoidal prism shape. The main body 2a and the case 19 are configured such that the length in the width direction x is smaller than the lengths in the length direction y and the vertical direction z. It can also be said that the underwater device 2 is configured to be thin in the width direction x.

[0074] Case 19 is composed of a member at least a part of whose wall surface is transparent. The wall surface within the range through which the light passing from the outer wall surface 10b to the camera 4 via the mirror 21 passes is composed of at least a transparent member. When the camera 4 is disposed outside the case 19, the part where the camera 4 peeks into the inside of the case 19 is composed of a transparent member. The other parts may be composed of a transparent member or a member that does not transmit light. The inside of the case 19 is filled with a transparent gas or a transparent liquid. Similarly, for the wall surface of the main body 2a, the wall surface within the range through which the light passing from the outer wall surface 10b to the mirror 21 passes is composed of at least a transparent member. The other parts of the wall surface of the main body 2a may be composed of a transparent member or a member that does not transmit light. In Fig. 19, for the sake of explanation, the shooting range of the camera 4 is surrounded by a straight line and the parts where seawater or the like exists are shaded.

[0075] The underwater device 2 may have a plurality of wheels 22 installed on the wall surface of the main body 2a which is the wall surface on one end side in the width direction x. These wheels 22 are configured to be rollable with the length direction y as the axial direction. The underwater device 2 may have one or a plurality of illuminations 7 installed on the wall surface where the wheels 22 are installed. The underwater device 2 may have a thruster 7 installed on the main body 2a. This thruster 7 is composed of, for example, a cylindrical member penetrating the main body 2a in the width direction and a propeller disposed inside this member with the width direction x as the axial direction. The thruster 7 generates a force on the underwater device 2 toward the direction where the wheels 22 are installed. The axial direction of the thruster 7 is not limited to the direction parallel to the width direction x. The axial direction of the thruster 7 may be set in a direction inclined at a predetermined angle with respect to the width direction x in the vertical direction z or the length direction y.

[0076] Case 19 may have a diaphragm 23 fixed to the wall surface that constitutes this case 19. This diaphragm 23 has a function of adjusting the pressure difference between the inside and outside of case 19. Since the diaphragm 23 can suppress the pressure difference between the inside and outside of case 19, it is advantageous for avoiding the problem that a force is generated in case 19 and it is damaged. A diaphragm 23 may be installed in case 19 of the embodiment illustrated in FIG. 14. The same effect as described above can also be obtained in the embodiment illustrated in FIG. 14.

[0077] When this underwater device 2 is dropped into the water, the underwater device 2 is pressed against the outer wall surface 10b by the thruster 7. 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 moves downward while photographing the outer wall surface 10b. The underwater device 2 that has reached the bottom of the ship 10c stops the thruster 7 and is pulled up to the water surface by the cable 5 or the like.

[0078] The wheels 22 may be installed on the main body 2a in a configuration where they can rotate passively. In this case, the wheels 22 do not have power such as that of a motor. The underwater device 2 pressed against the outer wall surface 10b by the thruster 7 descends by its own weight while maintaining contact between the wheels 22 and the outer wall surface 10b. The axial direction of the thruster 7 may be inclined upward in the vertical direction z, and the underwater device 2 may obtain a downward propulsive force by this thruster 7.

[0079] With a configuration in which the outer wall surface 10b is photographed through the mirror 21, even if the physical distance between the camera 4 and the outer wall surface 10b is reduced, the optical distance from the camera 4 to the outer wall surface 10b can be increased. The underwater device 2 can be miniaturized in the width direction x, and the optical distance from the camera 4 to the outer wall surface 10b can be increased.

[0080] Since the size of the underwater device 2 can be suppressed in the width direction x, it becomes easier to suppress the underwater device 2 from being washed in the length direction y under the influence of a tidal current or the like. Since it becomes difficult for the underwater device 2 to move in the length direction y, it is advantageous for moving the underwater device 2 along the vertical direction z.

[0081] By configuring the underwater device 2 to be pressed against the outer wall surface 10b by the thruster 7, it becomes easier to maintain a constant optical distance between the outer wall surface 10b and the camera 4. Even when the outer wall surface 10b is relatively largely curved, such as near the bow or stern of the ship 10, imaging can be performed while maintaining both the physical and optical distances between the outer wall surface 10b and the camera 4 constant. The underwater device 2 can easily obtain a clear image of the outer wall surface 10b.

Explanation of Signs

[0082] 1 Inspection device 2 Underwater device 2a Main body 2b Auxiliary structure 2c Arm part 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 Bottom of the ship 11 Fouled part 12 Exterior image 13 Guide mechanism 14 Wire 15 Weight 16 Support mechanism 17 Coupling 18 Attitude detection mechanism 19 Case 20 Bulge 21 Mirror 22 Wheel 23 Diaphragm P Inspection position S1 Horizontal position selection step S2 Imaging step S3 Acquisition step S4 Judgment step S5 Exterior image generation step S5a Completion step S6 Fouled condition judgment step Front direction (of underwater device) Distances d1, d2 Width direction x Length direction y Vertical direction z

Claims

1. In an inspection method for inspecting the fouling condition of the outer wall surface of a ship, a submersible device having a camera and a processing mechanism for acquiring data from the submersible device are provided in advance, the submersible device has a mirror disposed at a position in the shooting direction of the camera, and a case composed of a member at least a part of the wall surface of which is transparent and filled with a transparent gas or liquid inside, and the optical distance from the camera to the mirror is set to be larger than the optical distance from the mirror to the outer wall surface in advance, a horizontal position selection step of selecting one inspection position within the range from the bow to the stern of the ship, a shooting step of moving the submersible device having the camera along the vertical direction at the inspection position selected in the horizontal position selection step, and acquiring an image of the outer wall surface through the gas or liquid filled in the case and the mirror by the camera, an acquisition step of the processing mechanism acquiring data from the submersible device, characterized in that the horizontal position selection step, the shooting step, and the acquisition step are repeatedly executed.

2. The inspection method according to claim 1, wherein the camera has a configuration in which the shooting direction is downward in the vertical direction and is disposed near the upper end of the case, and the mirror has a configuration disposed near the lower end of the case.

3. The submersible device according to claim 1 or 2, wherein the submersible device has a main body in which the entire case is disposed inside and formed in a quadrangular prism shape, and the main body and the case are configured such that the length in the width direction that crosses the length direction at a right angle is smaller than the lengths in the length direction and the vertical direction, which are the directions connecting the bow and the stern of the ship.

4. The acquisition step has a configuration in which the processing mechanism acquires the data of the image acquired by the camera and the position information of the submersible device corresponding to the data of this image, and the processing mechanism includes an appearance image generation step of generating an appearance image in which a plurality of the images are arranged on a virtual outer wall surface based on the data acquired in the acquisition step, and the appearance image generation step has a configuration of generating the appearance image by adjusting and combining the vertical positions of the images of the outer wall surface respectively.

5. The inspection method according to claim 4, wherein the external appearance image generation step has a configuration in which, in the longitudinal direction that is the direction connecting the bow and the stern of the ship, the images of the outer wall surfaces are adjusted in their relative positions in the longitudinal direction and combined to generate the external appearance image.

6. In an inspection apparatus for inspecting the fouling condition of the outer wall surface of a ship, it 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 imaging direction of the camera and a case formed of a member at least partially transparent on the wall surface and filled with a transparent gas or liquid inside, and the optical distance from the camera to the mirror is set to be greater than the optical distance from the mirror to the outer wall surface, the camera has a configuration for acquiring an image of the outer wall surface through the gas or liquid filled in the case and the mirror, the inspection apparatus is characterized in that the underwater device acquires an image of the outer wall surface while moving along the vertical direction.

7. The inspection apparatus according to claim 6, wherein the camera has a configuration in which the imaging direction is downward in the vertical direction and is disposed near the upper end of the case, and the mirror has a configuration disposed near the lower end of the case.

8. The underwater device has a main body in which the entire case is disposed inside and is formed in a quadrangular prism shape, the main body and the case are configured such that the length in the width direction, which crosses the longitudinal direction at a right angle, is smaller than the lengths in the longitudinal direction and the vertical direction, which are the directions connecting the bow and the stern of the ship, according to claim 6 or 7.

9. It includes a position detection mechanism for acquiring vertical position information corresponding to the data of the image of the outer wall surface, the processing mechanism has a configuration in which the images of the outer wall surface are adjusted in their vertical positions and combined to generate an external appearance image according to claim 6 or 7.

10. The inspection apparatus according to claim 9, wherein the processing mechanism has a configuration in which, in the longitudinal direction that is the direction connecting the bow and the stern of the ship, the images of the outer wall surface are adjusted in their relative positions in the longitudinal direction and combined to generate the external appearance image.

Images