JP6155472B1 - Land / land determination device, land / land determination method, and underwater inspection device - Google Patents

Abstract

The land-and-land determination device determines whether the determination target is underwater or on land. This apparatus includes a detection member on which a specific image pattern is displayed, a camera, an image acquisition unit, and a determination unit. The camera is attached to the determination target, and the detection member is imaged at a first angle of view when in water and at a second angle of view wider than the first angle of view when in air. Is generated. The image acquisition unit acquires image data from the camera. The determination unit determines whether the determination target is on land or in water based on the image of the part of the detection member that is included in the image indicated by the acquired image data and changes according to the angle of view of the camera.

Description

  The present disclosure relates to an apparatus and method for determining whether an object is underwater or on land. The present disclosure also relates to an underwater inspection apparatus that inspects an underwater structure.

  Patent Document 1 discloses an underwater inspection apparatus that inspects underwater structures (dam walls, bridge girders, etc.). This underwater inspection apparatus has a propulsion unit (thruster) composed of a propeller, a motor, and the like, and moves underwater by the propulsion unit. The underwater inspection apparatus has a laser light source that irradiates laser light, and determines the actual scale of the inspection object based on the image of the inspection object irradiated with the laser light.

  Patent Document 2 discloses a method for determining whether it is underwater or on land based on the difference in absorption characteristics of light wavelengths. Patent Document 3 discloses a method for determining whether it is underwater or land based on the value of a pressure sensor.

Japanese Patent Laying-Open No. 2015-214335 JP-A-8-43724 JP 2008-236635 A

  The water and land determination apparatus according to the first aspect of the present disclosure determines whether the determination target is in water or on land. This apparatus includes a detection member on which a specific image pattern is displayed, a camera, an image acquisition unit, and a determination unit. The camera is attached to the determination target and images the detection member at a first angle of view when in water and at a second angle of view wider than the first angle of view when in air. Generate data. The image acquisition unit acquires image data from the camera. The determination unit determines whether the determination target is on land or in water based on the image of the part of the detection member that is included in the image indicated by the acquired image data and changes according to the angle of view of the camera.

  The underwater inspection apparatus according to the second aspect of the present disclosure captures an image of an inspection object in water. This device includes an underwater robot and a land and land determination device according to a first aspect that determines whether the underwater robot is on land or in water. The underwater robot has a propulsion unit that generates thrust for moving underwater. Among the land and land determination devices, at least the detection member and the camera are mounted on the underwater robot.

  In a third aspect of the present disclosure, a method for determining whether a determination target is in water or on land is provided. In the determination method, a detection member on which a specific image pattern is displayed is captured by a camera to generate image data, which is included in an image indicated by the image data, and when the camera is in the water and in the air Based on the image of the part of the detection member that changes according to the difference in the angle of view, it is determined whether the determination target is on land or in water.

  In the water and land determination apparatus according to the present disclosure, it is possible to detect whether an object is located in water or on land with a simple configuration such as a detection member and a camera. Moreover, since the underwater inspection apparatus of this indication also contains the said land and water determination apparatus, it can detect whether an underwater robot is located in the water or the land.

FIG. 1 is a block diagram illustrating a configuration of an underwater inspection apparatus equipped with a land / land determination apparatus according to Embodiment 1 of the present disclosure. FIG. 2 is an external view of the underwater robot of the underwater inspection apparatus shown in FIG. FIG. 3A is a view showing a detection plate of the underwater inspection apparatus shown in FIG. FIG. 3B is a view for explaining the attachment state of the detection plate shown in FIG. 3A. 4A illustrates the difference in the angle of view of the image captured by the control camera and the difference in the image of the detection plate included in the captured image when the underwater robot shown in FIG. 2 is underwater or on land. FIG. FIG. 4B is a diagram illustrating the angle of view of an image captured by the control camera when the underwater robot illustrated in FIG. 2 is underwater. FIG. 4C is a diagram illustrating the angle of view of an image captured by the control camera when the underwater robot illustrated in FIG. 2 is on land. FIG. 5A is a diagram illustrating an angle of view of an image captured by the control camera when the underwater robot illustrated in FIG. 2 is underwater. FIG. 5B is a diagram illustrating an image of the detection plate captured by the steering camera when the underwater robot shown in FIG. 2 is underwater. FIG. 5C is an enlarged view of FIG. 5B. FIG. 6A is a diagram illustrating the angle of view of an image captured by the control camera when the underwater robot illustrated in FIG. 2 is on land. FIG. 6B is a diagram illustrating an image of the detection plate photographed by the steering camera when the underwater robot shown in FIG. 2 is on land. FIG. 6C is an enlarged view of FIG. 6B. FIG. 7 is a diagram for explaining land / land determination based on the luminance difference / normalized luminance difference in the land / land determination apparatus according to Embodiment 1 of the present disclosure. FIG. 8 is a flowchart illustrating the land and land determination process using the image of the detection plate in the land and land determination apparatus according to Embodiment 1 of the present disclosure. FIG. 9 is a diagram for describing a land / land determination process in consideration of image information and water depth of a detection plate in the land / land determination apparatus according to the first embodiment of the present disclosure. FIG. 10 is a flowchart illustrating the land / land determination process in consideration of the image information and the water depth of the detection plate in the land / land determination apparatus according to Embodiment 1 of the present disclosure. FIG. 11 is a flowchart showing a lock process / unlock process for the underwater robot in the underwater inspection apparatus shown in FIG. FIG. 12 is a diagram illustrating the functions of the CPU and the information stored in the memory in the PC of the underwater inspection apparatus according to the second embodiment of the present disclosure. FIG. 13A is a diagram showing luminance difference-turbidity correspondence information indicating the relationship between the turbidity of water stored in the memory of the underwater inspection apparatus shown in FIG. 12 and the luminance difference (contrast) of the detection plate image. FIG. 13B is a diagram showing turbidity-distance correspondence information indicating the relationship between the turbidity of water stored in the memory of the underwater inspection apparatus shown in FIG. 12 and the distance to the subject. FIG. 14 is a flowchart illustrating processing for controlling the distance to the subject based on the turbidity of water in the underwater inspection apparatus according to Embodiment 2 of the present disclosure. FIG. 15A is a diagram illustrating a configuration of another detection plate according to the embodiment of the present disclosure. FIG. 15B is a diagram showing an image pattern of the detection plate shown in FIG. 15A. FIG. 15C is a view showing an image of the detection plate shown in FIG. 15A, which is taken when the underwater robot is underwater. FIG. 15D is a diagram showing an image of the detection plate shown in FIG. 15A, which is taken when the underwater robot is on land. FIG. 16 is a diagram for explaining land and land determination based on the luminance ratio in the embodiment of the present disclosure.

  Prior to the description of the embodiments of the present disclosure, problems in the conventional underwater inspection apparatus will be briefly described. The propeller and laser light source in the underwater inspection apparatus are necessary for the function and operation of the underwater inspection apparatus in water, and do not need to be operated on land. However, if there is an erroneous operation by the driver, the propeller and the laser light source will operate even on land. Therefore, there is a problem in safety.

  The present disclosure provides a determination device and a determination method that can determine whether an object is in water or on land. Furthermore, the present disclosure provides an underwater inspection apparatus that can prevent an unintended operation due to an erroneous operation or the like when on land.

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

Incidentally, the accompanying drawings and the description below, one skilled in the art is not more being provided for the full understanding of the present disclosure and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
[1-1. Constitution]
FIG. 1 is a block diagram illustrating an example of a configuration of an underwater inspection device equipped with the land and land determination device of the present disclosure. The underwater inspection apparatus 10 captures an image of the surface of a structure in water in order to inspect a submerged portion (for example, a dam wall surface, a bridge girder, etc.) of a structure such as a dam or a bridge. The underwater inspection apparatus 10 includes an underwater robot 100 that captures an image of a structure underwater while moving underwater, and a ground unit 200 that controls the operation of the underwater robot 100 on the ground. The underwater robot 100 and the ground unit 200 are connected by a communication cable (for example, an electric wire for passing an electric signal) 300. The operator operates the controller 220 to control the underwater robot 100 while viewing the operation image sent from the underwater robot 100. Hereinafter, specific configurations of the underwater robot 100 and the ground unit 200 will be described.

[1-1-1. Ground unit]
The ground unit 200 includes a personal computer (hereinafter referred to as a PC) 250 that gives instructions to each part of the underwater inspection apparatus 10, a controller 220 that is operated by the operator, and a communication unit 230 that performs communication between the PC 250 and the underwater robot 100. Including.

  The underwater robot 100 and the ground unit 200 are connected by a communication cable 300. The communication cable 300 is an electric wire for transmitting an electrical signal, for example. The communication unit 230 is a unit that converts data from the PC 250 into a predetermined communication protocol (for example, PLC (Power Line Communication)) suitable for communication with electric wires for transmitting electrical signals. Communication between the PCs 250 is realized.

  The PC 250 includes a display unit 211, a communication interface unit (communication I / F unit) 212 that is an example of an image acquisition unit, a CPU 210 that is an example of a determination unit and a control unit, and a memory 218.

  The display unit 211 includes a liquid crystal display or an organic EL display. The display unit 211 displays an operation image (moving image) transmitted from the underwater robot 100. The communication I / F unit 212 communicates with the communication unit 230 according to a predetermined standard (for example, LAN standard).

  The CPU 210 implements various functions by executing programs. For example, the CPU 210 implements the functions of the luminance difference calculation unit 214 and the land / land determination unit 216 by executing a program. The CPU 210 acquires an operation image (moving image) taken underwater from the underwater robot 100 via the communication I / F unit 212.

  The memory 218 is a non-volatile memory such as a flash memory, and stores information necessary for the processing of the CPU 210.

  The controller 220 transmits an instruction for the operator to operate the underwater robot 100. The controller 220 includes an operation foil, an operation stick, a switch, and the like. The pilot operates the underwater robot 100 by operating the controller 220 while viewing the control image displayed on the display unit 211.

[1-1-2. Underwater robot]
FIG. 2 is an external view of the underwater robot 100. The underwater robot 100 performs a movement and an image capturing operation according to a command from the ground unit 200, and transmits a steering image to the ground unit 200 via the communication cable 300. The configuration of the underwater robot 100 will be described with reference to FIGS. 1 and 2.

  The underwater robot 100 includes a main unit 110, a lighting device 120, a thruster 130, a sonar 140, an inspection camera 150, a battery 160, a detection plate 170, a laser 180, and a pressure sensor 190. The underwater robot 100 has a frame 105, and each component is attached to the frame 105 as shown in FIG.

  The main unit 110 includes a communication unit 112 for communicating with the ground unit 200, a control unit 114 for controlling the operation of the underwater robot 100, and a control camera 116 for capturing an image for the operator. The main unit 110 is accommodated in a waterproof container 118 having a waterproof property. The control unit 114 includes a CPU and executes a function by executing a predetermined program. The steering camera 116 shoots an image (moving image or still image) for the pilot on the ground to check the position of the underwater robot 100 and the underwater state. An image taken by the steering camera 116 is transmitted to the ground unit 200 via the communication unit 112. The communication unit 112 communicates with the ground unit 200 according to a predetermined communication standard (for example, PLC).

  The illumination device 120 is a device that irradiates a subject with light in order to take an image, and includes a light source (for example, an LED element) and an optical system. The thruster 130 is an example of a propulsion unit that provides the propulsive force of the underwater robot 100, and includes, for example, a screw and a motor. In order to enable the underwater robot 100 to move in three dimensions, a plurality of thrusters 130 are attached in three axial directions. The sonar 140 measures the distance from the underwater robot 100 to an object underwater using sound waves. The underwater object is, for example, a wall surface of a dam. The battery 160 is a rechargeable battery and supplies electric power for driving the underwater robot 100. The pressure sensor 190 detects the pressure around the underwater robot 100. The laser 180 irradiates a laser beam for measuring the size of the inspection object.

  The inspection camera 150 captures an image of a structure underwater, and records image data generated by the capture on an internal recording medium. The inspection camera 150 is an example of a second camera, and the recording medium is, for example, a memory card. The image data may be still image data or moving image data. Since the inspection camera 150 captures an inspection image, the inspection camera 150 can capture a higher-definition image (for example, a 4K image) than the steering camera 116.

  The underwater robot 100 has a vertical direction, a horizontal direction, and a front-rear direction as shown in FIG. The direction of the subject whose image is captured by the steering camera 116 and the inspection camera 150 is defined as the forward direction, and the direction from the inspection camera 150 toward the steering camera 116 is defined as the upward direction. The underwater robot 100 does not collide with the inspection object in the up, down, left, and right directions when facing the inspection object, that is, with the optical axes of the steering camera 116 and the inspection camera 150 being substantially orthogonal to the inspection object. As described above, an image of the surface of the inspection object is taken while moving in parallel.

[1-1-3. Detection plate]
FIG. 3A is a diagram showing an image pattern of the detection plate 170. As illustrated in FIG. 3A, the detection plate 170, which is an example of a detection member, includes an upper region 170a that includes a white region and a black region, and a lower region 170b that includes a black region and a white region. In the upper region 170a and the lower region 170b, the white region and the black region are arranged in reverse.

  FIG. 3B is a diagram illustrating a state where the detection plate 170 is attached. The detection plate 170 is supported by a support member 185 and fixed to the upper part of the waterproof container 118. In particular, the detection plate 170 is disposed between the illumination device 120 and the steering camera 116 such that a plane on which an image pattern is formed faces downward and faces the steering camera 116. That is, the plane on which the image pattern of the detection plate 170 is formed corresponds to the vertical direction and the horizontal direction perpendicular to the vertical direction when the underwater robot 100 is in a posture in which the vertical direction and the vertical direction match. Spread in the direction between. By arranging the detection plate 170 in this way, sunlight incident from above is blocked by the lighting device 120 and the detection plate 170 and does not reach the steering camera 116. For this reason, when the water depth is shallow, it can be excluded that sunlight enters the detection plate 170. In addition, since the illumination light from the illumination device 120 is blocked by the detection plate 170 and does not reach the control camera 116, the influence of the illumination light on the detection plate 170 when the water depth is deep can be eliminated. The light source for the detection plate 170 is scattered light from the surroundings or reflected light that has passed through the path including the inspection object, the waterproof container 118 and the detection plate 170 from the illumination device 120. With the configuration as shown in FIG. 3B, a stable black-and-white contrast difference can be detected without saturation of the white area of the detection plate 170 in the image captured by the steering camera 116.

  FIG. 4A is a diagram for explaining the angle of view (shooting range) of the steering camera 116 when the detection plate 170 is viewed from the steering camera 116. Due to the difference in refractive index between water and air, the angle of view (shooting range) when the control camera 116 is in water is more than the angle of view (shooting range) when the control camera 116 is on land (in the air). Narrow. That is, as shown in FIG. 4A, the angle of view (shooting range) R1 when the control camera 116 is underwater is larger than the view angle (shooting range) R2 when the control camera 116 is on land (in the air). Becomes narrower. Therefore, the land / land determination can be performed using the difference in the angle of view between the underwater and the land.

  In the present embodiment, when the underwater robot 100 (that is, the steering camera 116) is underwater, the lower region 170b of the detection plate 170 is located at a predetermined position in the image captured by the steering camera 116. When the steering camera 116 is on land (in the air), the upper region 170a of the detection plate 170 is located at a predetermined position in the captured image. The relative positional relationship between the detection plate 170 and the steering camera 116 is set so as to be in such a state.

  That is, when the steering camera 116 is underwater, as shown in FIG. 4B, the lower region 170b of the detection plate 170 is located at a predetermined position (upper center) in the captured image IM. When the steering camera 116 is on land, as shown in FIG. 4C, the upper region 170a of the detection plate 170 is located at a predetermined position (upper center) of the captured image IM. Thereby, the image pattern of the detection plate 170 included in the predetermined position in the captured image IM differs depending on the angle of view that changes between when the underwater robot 100 is underwater and when it is on land. By detecting such a difference (for example, luminance difference) in the image pattern of the detection plate 170, it is possible to detect whether the underwater robot 100 is underwater or on land.

  An image captured by the steering camera 116 when the underwater robot 100 is underwater will be described with reference to FIGS. 5A to 5C. When the underwater robot 100 is underwater, the angle of view of the control camera 116 is a narrow angle of view R1 as shown in FIG. 5A. At this time, an image IM as shown in FIG. 5B is taken by the steering camera 116. That is, a part or all of the lower region 170b of the detection plate 170 is included in the upper center region R10 of the image IM, and the image of the upper region 170a is not included. The image presented (displayed) to the pilot may be an image obtained by removing the image of the detection plate 170 from the image captured by the steering camera 116 (see FIG. 5B). This is because information on the detection plate 170 is not necessary for maneuvering.

  FIG. 5C is an enlarged view of a region R10 in FIG. 5B. In the present embodiment, the PC 250 detects the image of the detection plate 170 based on the image information (luminance difference) of the detection plate 170 reflected in each of the left region R11 and the right region R12 in the upper center region R10 in the captured image IM. Detect pattern differences.

  Next, an image captured by the control camera 116 when the underwater robot 100 is on land will be described with reference to FIGS. 6A to 6C. When the underwater inspection apparatus 10 is on land, the angle of view of the steering camera 116 is a wide angle of view R2 as shown in FIG. 6A. At this time, an image IM as shown in FIG. 6B is taken by the steering camera 116. That is, in the upper center region R10 of the image IM, an image of a portion of the upper region 170a in addition to the lower region 170b of the detection plate 170 is included. FIG. 6C is an enlarged view of a region R10 in FIG. 6B. Based on the image information (luminance difference) of the detection plate 170 reflected in each of the left region R11 and the right region R12 in the upper center region R10 in the captured image IM, a difference in the image pattern of the detection plate 170 is detected.

  Specifically, when the underwater robot 100 is underwater, as shown in FIG. 5C, in the captured image, the left region R11 is a black region and the right region R12 is a white region. On the other hand, when the underwater robot 100 is on land (in the air), as shown in FIG. 6C, in the captured image, the left region R11 is a white region and the right region R12 is a black region. Therefore, the underwater inspection apparatus 10 can determine whether the underwater robot 100 is underwater or on land by determining the luminance difference obtained by subtracting the luminance of the left region R11 from the luminance of the right region R12. it can. When the underwater robot 100 is underwater, as shown in FIG. 7, the luminance difference (the luminance of the right region R12−the luminance of the left region R11) varies greatly depending on the degree of turbidity of water. Become. On the other hand, when the underwater robot 100 is on land, the luminance difference is a negative value. At this time, the luminance difference is not greatly affected by the disturbance and the variation is small.

  It should be noted that by using the information of the partial areas R11 and R12 of the entire area of the captured image, even when there is a variation in the mounting position of the detection plate 170 or the steering camera 116, the black area and the white area are accurately obtained. It becomes possible to extract the information.

[1-2. Operation]
The operation of the underwater inspection apparatus 10 configured as described above will be described below.

[1-2-1. Land and land judgment operation]
A description will be given of the land / land determination operation for determining whether the underwater robot 100 in the underwater inspection apparatus 10 is underwater or on land.

  FIG. 8 is a flowchart showing the land and land determination process in the ground unit 200 of the underwater inspection apparatus 10. The land and land determination process will be described with reference to FIG.

  CPU210 of PC250 in the ground unit 200 acquires the image image | photographed with the steering camera 116 of the underwater robot 100 via the communication unit 230 and the communication I / F part 212 (S21). The luminance difference calculation unit 214 of the CPU 210 calculates the luminance of each of the left region R11 and the right region R12 from the captured image (S22). Specifically, as shown in FIGS. 5C and 6C, the average brightness value is obtained for each of the left region R11 and the right region R12 in the captured image, thereby obtaining the brightness values of the regions R11 and R12.

  Further, the luminance difference calculation unit 214 obtains a normalized luminance difference from the luminances of the left region R11 and the right region R12 (S23). Here, the normalized luminance difference is calculated by normalizing the difference between the luminance of the left region R11 and the luminance of the right region R12 of the captured image using the luminance of the white region as in the following equation. In this case, the white area is an area having a higher luminance of the left area R11 and the right area R12.

Normalized luminance difference = (right region luminance−left region luminance + A) / white region luminance × B + C (1)
Here, A, B, and C are correction coefficients. By normalizing, it is possible to reduce the fluctuation of the absolute value due to the ambient light quantity (whether lighting is present, weather, water depth, etc.). Instead of the normalized luminance difference, a value obtained by subtracting the luminance of the left region R11 from the luminance of the right region R12 (unnormalized luminance difference) may be used.

  Then, the land / land determination unit 216 of the CPU 210 determines whether the underwater robot 100 is underwater or on land (in the air) from the calculated normalized luminance difference (S24). Specifically, the normalized luminance difference is compared with a predetermined threshold (for example, 0). When the normalized luminance difference is larger than the threshold value, it is determined that the underwater robot 100 is underwater. When the normalized luminance difference is equal to or less than the threshold value, it is determined that the underwater robot 100 is on land.

  As described above, the land / land determination can be performed based on the captured images having different angles of view depending on whether the underwater robot 100 is in water or on land.

  In the above land-and-land determination process, the land-and-land determination is performed based only on the image information of the detection plate 170. However, in this case, accurate image information cannot be obtained depending on conditions, and an erroneous land-and-land determination may be made. For example, when the turbidity of water is very large at a deep location in the water, or when the lighting device 120 is turned off at a deep location in the water, clear image information cannot be obtained. For this reason, it may be erroneously determined to be land although it is underwater. Therefore, a description will be given below of a land / land determination process (hereinafter referred to as “second land / land determination process”) that can accurately determine the land / land even under such circumstances.

  In the second land / land determination process shown in FIG. 9, the land / land determination is performed based on the image information of the detection plate 170 and the water depth information. The water depth information is obtained from the detection value of the pressure sensor 190. As shown in FIG. 9, when the luminance difference or the normalized luminance difference calculated from the image information is equal to or smaller than a threshold A and the water depth is equal to or smaller than a threshold B (for example, 1 m), the underwater robot 100 is on land. Otherwise, it may be determined that the underwater robot 100 is underwater.

  According to the second water and land determination process shown in FIG. 9, even if it is determined that the underwater robot 100 is “land” based on the luminance difference or the normalized luminance difference obtained from the image information, Is deep (greater than the threshold value B), it is determined that the underwater robot 100 is “underwater”. Therefore, even when the turbidity of water is very large at a deep location in the water or when the lighting device 120 is turned off at a deep location in the water, the value by the pressure sensor 190 is a deep water depth (a value greater than the threshold value B). ), It is correctly determined that the underwater robot 100 is “underwater”.

  FIG. 10 is a flowchart showing the second land and land determination process. The second land / land determination process will be described with reference to FIG.

  The CPU 210 of the PC 250 in the ground unit 200 acquires an image photographed by the steering camera 116 of the underwater robot 100 via the communication unit 230 and the communication I / F unit 212 (S31). The luminance difference calculation unit 214 of the CPU 210 calculates the luminance of each of the left region R11 and the right region R12 from the captured image (S32).

  Subsequently, the luminance difference calculation unit 214 obtains a normalized luminance difference from the luminances of the left region R11 and the right region R12 (S33). The operation from step S31 to step S33 is the same as that from step S21 to step S23.

  And CPU210 acquires the detected value detected with the pressure sensor 190 of the underwater robot 100 via the communication unit 230 and the communication I / F part 212 (S34).

  The water and land determination unit 216 of the CPU 210 determines whether the underwater robot 100 is underwater or on land (S35). Specifically, the CPU 210 calculates the water depth from the detection value of the pressure sensor 190 and, based on the relationship shown in FIG. 9, determines whether the underwater robot 100 is underwater or on land based on the normalized luminance difference and the water depth. to decide.

  As described above, the land and water determination may be performed based on the image information of the detection plate 170 and the water depth information. The threshold value B regarding the water depth may be set as appropriate in consideration of variations (offset) of the pressure sensor 190. As the variation factor, the altitude of the place to be inspected and the atmospheric pressure fluctuation can be considered.

[1-2-2. Lock / unlock operation]
Next, the lock operation / unlock operation for the underwater robot 100 in the underwater inspection apparatus 10 will be described. The lock operation refers to an operation for bringing the underwater robot 100 into a locked state. The locked state refers to a state in which the underwater robot 100 does not accept an operation instruction other than unlocking (for example, a forward instruction or a camera photographing instruction). Further, the unlocking operation refers to an operation for making all operation instructions acceptable from the locked state. For example, the operator can perform an operation for a locking operation or an operation for an unlocking operation by performing a predetermined operation on the controller 220.

  With reference to the flowchart of FIG. 11, the lock operation / unlock operation of the underwater inspection apparatus 10 will be described. It is assumed that the underwater robot 100 is in a locked state at the start of processing in this flowchart.

  The CPU 210 waits for reception of a lock release instruction based on the operator's operation (S41). When the unlocking operation is accepted (Y in S41), the CPU 210 performs a land / land determination process for determining whether the underwater robot 100 is underwater or on land (S42). The land and land determination processing is as described above (see FIGS. 8 and 10).

  As a result of the water and land determination, when it is determined that the vehicle is on land (S43), the process returns to step S41 without unlocking. On the other hand, when it is determined that it is underwater (S43), the CPU 210 releases the lock on the underwater robot 100 (S44). When the underwater robot 100 is underwater, the underwater robot 100 is unlocked because it is necessary to take an image of the inspection object and move it according to the operation of the operator.

  Thereafter, the CPU 210 waits for reception of a lock instruction based on the operator's operation (S45). When the lock instruction is received (Y in S45), the CPU 210 performs a locking operation on the underwater robot 100 (S48), and returns to step S41. As a result, the underwater robot 100 does not accept any operation instruction other than unlocking, and the underwater robot 100 can be prevented from malfunctioning.

  On the other hand, when the lock instruction has not been received (N in S45), the CPU 210 executes a land / land determination process (see FIGS. 8 and 10) (S46).

  As a result of the land and land determination, when it is determined that the vehicle is underwater (S47), the process returns to step S45. In this case, the operation of the underwater robot 100 can be continued.

  On the other hand, when it is determined that the vehicle is on land (S47), the CPU 210 performs a locking operation on the underwater robot 100 (S48). Thereafter, the process returns to step S41. As described above, when it is detected that the underwater robot 100 is on land, the underwater robot 100 is automatically locked. As a result, the underwater robot 100 does not accept any operation instruction other than unlocking, the malfunction of the underwater robot 100 can be prevented, and safety is improved.

  As described above, the underwater inspection apparatus 10 determines whether the underwater robot 100 is underwater or on land, and automatically performs a lock operation / unlock operation based on the determination result. In particular, when the underwater robot 100 is on land, it is possible to prevent the underwater robot 100 from malfunctioning on land by automatically performing a locking operation, thereby improving safety.

[1-3. Effect]
As described above, the land / land determination apparatus in the underwater inspection apparatus 10 includes the detection plate 170 on which a specific image pattern is displayed, the steering camera 116, the steering camera 116, and the communication I / O as an example of the image acquisition unit. It has F section 212 and CPU210 as an example of a determination part. The detection plate 170 and the steering camera 116 are attached to the underwater robot 100 that is an example of a determination target. The steering camera 116 captures the detection plate 170 at a first angle of view R1 when in water and at a second angle of view R2 wider than the first angle of view when in air, and outputs image data. Is generated. The communication I / F unit 212 acquires image data from the steering camera 116. The CPU 210 includes the underwater robot 100 based on the image of the part of the detection plate 170 (upper region 170a, lower region 170b) that is included in the image indicated by the acquired image data and changes according to the angle of view of the steering camera 116. Determine if you are on land or underwater. As described above, at least the detection plate 170 and the steering camera 116 are mounted on the underwater robot 100 in the land and water determination apparatus.

  The water and land determination device in the underwater inspection device 10 can detect whether the underwater robot 100 is located underwater or on land based on the image of the detection plate 170. That is, the land and land determination can be performed with a simple configuration in which only the detection plate 170 and the steering camera 116 are provided. Further, when it is determined that the underwater inspection apparatus 10 is on land, the function of the underwater inspection apparatus 10 is locked, so that an unintended operation due to an erroneous operation can be prevented, and safety can be improved.

  In the underwater robot 100 shown in FIG. 2, some of the thrusters 130 are provided above the steering camera 116 that constitutes the land and land determination device. However, it is preferred that all thrusters 130 and lasers 180 be located at the same position or below in the vertical direction relative to the steering camera 116. That is, in the underwater robot 100, all the thrusters 130 and the lasers 180 need only be arranged on one side with respect to the position where the control camera 116 is mounted. In this case, depending on the posture of the underwater robot 100, the thruster 130 and the laser 180 are positioned at the same position or below in the vertical direction from the steering camera 116. Thus, when the land / land determination unit 216 determines that the underwater robot 100 is underwater, all the thrusters 130 and the lasers 180 are in the water. With this configuration, the safety due to the above-described lock function is further increased.

  In this embodiment, a method for determining whether the underwater robot 100 (an example of an object) is in water or on land is also disclosed. In the determination method, the detection plate 170 on which a specific image pattern is displayed is photographed by the steering camera 116 to generate image data. The portion of the detection plate (upper region 170a, lower side) that is included in the image indicated by the image data and changes according to the difference between the view angles R1 and R2 when the steering camera 116 is in the water and in the air Based on the image of the area 170b), it is determined whether the underwater robot 100 is on land or underwater.

(Embodiment 2)
In the present embodiment, a configuration of an underwater inspection apparatus having a function of determining the turbidity of water in addition to the land and land determination function described in the first embodiment will be described. The underwater inspection apparatus of the present embodiment has the same hardware configuration as the configuration shown in the first embodiment (see FIGS. 1 and 2).

  FIG. 12 is a block diagram of ground unit 200A in the underwater inspection apparatus of the present embodiment. In the present embodiment, the CPU 210 of the ground unit 200A further realizes the functions of the turbidity calculator 215 and the distance calculator 217. The memory 218 stores luminance difference / turbidity correspondence information (information) 218a and turbidity / distance correspondence information (information) 218b. The information 218a indicates the relationship between turbidity and the normalized luminance difference, and the information 218b indicates the relationship between the detected turbidity and the subject distance (distance to the inspection object).

  FIG. 13A shows information 218a indicating the relationship between turbidity and normalized luminance difference. The lower the turbidity of water, the larger the difference (contrast) between the luminance of the black region and the luminance of the white region of the detection plate 170. The higher the turbidity in water, the smaller the luminance difference.

  FIG. 13B shows information 218b indicating the relationship between the detected turbidity and the subject distance (distance to the inspection target (control target value)). When the turbidity of water is low, a clear inspection image can be taken even if the distance between the inspection target and the underwater robot 100 is long. On the other hand, when the turbidity of water is high, a clear inspection image cannot be taken if the distance between the inspection target and the underwater robot 100 is long. For this reason, it is necessary to bring the underwater robot 100 closer to the inspection target as the turbidity is higher. Therefore, as shown in FIG. 13B, the higher the turbidity, the shorter the subject distance (distance to the inspection object (control target value)) is set by operating the thruster 130.

  FIG. 14 is a flowchart showing processing for controlling the subject distance (distance to the inspection object) based on the turbidity of water in the underwater inspection apparatus according to the present embodiment.

  The turbidity calculation unit 215 of the CPU 210 calculates turbidity from the obtained normalized luminance difference with reference to the information 218a shown in FIG. 13A based on the normalized luminance difference calculated in the land and land determination process (S51). Next, the distance calculation unit 217 refers to the information 218b shown in FIG. 13B and calculates a distance to be set from the obtained turbidity to the inspection object (subject) (S52).

  The CPU 210 of the PC 250 in the ground unit 200A controls the position of the underwater robot 100 so that the distance from the underwater robot 100 to the inspection object becomes the calculated distance (S53). At this time, the sonar 140 measures the distance from the underwater robot 100 to the inspection object using sound waves. The underwater robot 100 controls the thruster 130 in accordance with an instruction from the PC 250 to maintain the distance between the underwater robot 100 and the inspection target at a specified distance.

  With the control as described above, the distance from the underwater robot 100 to the inspection object can be controlled to a distance according to the turbidity of water. That is, as the turbidity increases, the distance is controlled so that the distance between the underwater robot 100 and the inspection object (subject) becomes shorter. Thereby, even when the turbidity is high, it is possible to capture an image in which deterioration in image quality is suppressed.

  As described above, according to the underwater inspection apparatus of the present embodiment, the image information of the detection plate 170 for land and land determination can also be used for turbidity determination, which is newly added to the configuration of the first embodiment. The turbidity determination function can be added without adding physical components.

(Other embodiments)
As described above, Embodiments 1 and 2 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed. Moreover, it is also possible to combine each component demonstrated in the said Embodiment 1-2 and it can also be set as a new embodiment. Therefore, other embodiments will be exemplified below.

  In the first and second embodiments, the detection plate 170 is mounted on the underwater robot 100 as a detection member on which a specific image pattern is displayed, but the shape of the detection member is not limited to a plate shape. A columnar shape or the like may be used as long as a specific image pattern is provided on the surface.

  In the first and second embodiments, the turbidity is determined based on the information (luminance difference and resolution) of the image captured by the steering camera 116 of the underwater robot 100, but from the information of the image captured by the inspection camera 150. Turbidity may be determined.

  In the first and second embodiments, the steering camera 116 that shoots the steering image and the inspection camera 150 that shoots the inspection image are provided separately. However, the steering image and the inspection image are provided. You may make it image | photograph with the same camera.

  The configuration of the detection plate 170 is not limited to that in which a white region and a black region are arranged in a checkerboard shape as shown in FIG. 3A and the like. The image pattern of the detection plate 170 may be set so that different images are taken by the steering camera 116 at each of the angle of view R1 in water and the angle of view R2 in air. For example, as shown in FIGS. 15A and 15B, a white region and a black region may be arranged vertically. At this time, as shown in FIG. 15C and FIG. 15D, in each of the angle of view R1 when the control camera 116 is underwater and the angle of view R2 when it is on land (in the air), in a predetermined region R13 of the captured image. What is necessary is just to set the relative position of the detection plate 170 and the steering camera 116 so that the area | region of a different color may be included. Thereby, the land and water determination can be performed based on the color of the predetermined region R13 of the captured image. Alternatively, a rectangular object is photographed on the portion of the detection plate 170 included in the image photographed at the angle of view R1 in water, and a circle is formed on the portion of the detection plate 170 included in the image photographed at the angle of view R2 in the air. The image pattern of the detection plate 170 may be set so that a shape object is photographed.

  In the first and second embodiments, the image pattern provided on the detection plate 170 is composed of a white region and a black region. However, the colors of the two areas constituting the image pattern are not limited to black and white. The image pattern only needs to be composed of two areas with different brightness. That is, the image pattern only needs to be composed of a dark region and a bright region composed of a brighter color than the dark region.

  In the first and second embodiments, the predetermined areas R11 and R12 on the captured image when detecting the luminance are arranged at the center position on the upper side of the captured image IM, but the positions of the predetermined areas R11 and R12 are not limited thereto. The positions of the predetermined regions R11 and R12 may be on the lower side or the lateral side of the captured image IM. Moreover, the end may be sufficient instead of the center. That is, the position may be any position where the change in the angle of view affects when the steering camera 116 is underwater or when it is on land.

  In the first and second embodiments, the land and water determination is performed on the basis of a change in luminance difference that changes in accordance with the angle of view regarding an image (an image on the detection plate 170) in a predetermined region on the captured image. The land and land determination may be performed based on a change in the image pattern of the portion of the detection plate 170 in the captured image that changes according to the angle of view. For example, when taken in water, as shown in FIG. 4B, the captured image IM includes only the lower region 170b portion of the detection plate 170, and when taken on land (in the air), shown in FIG. 4C. As described above, the captured image IM includes an image of the upper region 170a in addition to the lower region 170b of the detection plate 170. The land and water determination may be performed by detecting a difference in the image of the detection plate 170 included in the captured image IM that changes in accordance with the angle of view.

  In the first and second embodiments, the land and land determination is performed based on the value of the luminance difference between the region R11 and the region R12. However, as shown in FIG. 16, the ratio between the luminance of the region R11 and the luminance of the region R12 may be used. In this case, the land and water determination can be performed based on a comparison result between the luminance ratio and a predetermined threshold (for example, 1).

  The configuration of turbidity detection shown in the second embodiment is not limited to the detection of turbidity of water, but can also be applied to the detection of turbidity of other fluids other than water.

  Further, the CPU 210 functions as a control unit that controls the distance between the inspection object and the underwater robot 100 by controlling the thruster 130 that is a propulsion unit based on the turbidity detected by the turbidity calculation unit 215. However, the control unit 114 mounted on the underwater robot 100 may have this function.

  In the first and second embodiments, the CPU 210 functions as a control unit that prevents a predetermined operation from being performed on the underwater robot 100 when the determination result by the water and land determination unit 216 indicates that the underwater robot 100 is on land. To do. However, the control unit 114 mounted on the underwater robot 100 may have this function.

  In either case, information for performing the function is transmitted from the ground unit 200 or the ground unit 200A to the underwater robot 100 via the communication units 230 and 112. As described above, the function of the CPU 210 may be executed by the control unit 114, and conversely, the function of the control unit 114 may be executed by the CPU 210.

  The program executed by the CPU 210 in the first and second embodiments may be provided by a recording medium such as a DVD-ROM or a CD-ROM, or may be downloaded from a server on the network via a communication line. The functions of the CPU 210 described above are realized by cooperation of hardware and software (application program). However, the functions may be realized only by a hardware circuit designed exclusively for realizing a predetermined function. Therefore, instead of the CPU 210, the above-described functions may be realized by an MPU, DSP, FPGA, ASIC, or the like. The function of the CPU 210 described above may be realized by one device or a plurality of devices.

  As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided.

  Accordingly, among the components described in the accompanying drawings and the detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

Further, the above-mentioned embodiment, since it is intended to illustrate the technique of the present disclosure, various modifications within the scope or range of equivalents of the claims, substitutions, additions, can be performed and omissions.

  The present disclosure can be applied to an object or device that is used or operates in water, and is useful, for example, for an inspection device that inspects an object (dam wall, bridge girder, etc.) in water.

DESCRIPTION OF SYMBOLS 10 Underwater inspection apparatus 100 Underwater robot 110 Main body unit 112 Communication unit 114 Control unit 116 Steering camera 120 Illumination device 130 Thruster 140 Sonar 150 Inspection camera 160 Battery 170 Detection plate 180 Laser 190 Pressure sensor 200, 200A Ground unit 210 CPU
211 Display Unit 214 Brightness Difference Calculation Unit 215 Turbidity Calculation Unit 216 Aqualand Determination Unit 217 Distance Calculation Unit 212 Communication Interface Unit (Communication I / F Unit)
218 Memory 218a Luminance difference-turbidity correspondence information (information)
218b Turbidity-distance correspondence information (information)
220 Controller 230 Communication unit 250 Personal computer (PC)
300 Communication cable

Claims (10)

An apparatus for determining whether the determination target is underwater or on land,
A detection member attached to the determination target and displaying a specific image pattern;
The detection member is photographed at a first angle of view when attached to the determination target and is in water, and at a second angle of view wider than the first angle of view when in air. A camera that generates
An image acquisition unit for acquiring the image data from the camera;
A determination unit that determines whether the determination target is on land or in water based on an image of a portion of the detection member that is included in an image indicated by the acquired image data and changes according to an angle of view of the camera; With
Land and land judgment device. In the image taken at the second angle of view, the first portion and the second portion of the detection member are included,
The relative position between the detection member and the camera so that the first portion of the detection member is included and the second portion is not included in the image photographed at the first angle of view. Relationship is set,
The land and water determination apparatus according to claim 1. A lighting device;
The detection member is disposed between the lighting device and the camera in a state where the surface on which the specific image pattern is displayed faces the camera.
The land and water determination apparatus according to claim 1. The determination unit determines whether the determination target is on land or in water based on an image included in a predetermined region in the image indicated by the image data.
The land and water determination apparatus according to claim 1. The specific image pattern is a pattern having a dark region and a bright region composed of a brighter color than the dark region,
The determination unit determines whether the determination target is on land or in water based on the difference between the brightness of the bright area and the brightness of the dark area.
The land and water determination apparatus according to claim 1. The specific image pattern is a pattern in which the dark area and the bright area are alternately arranged in the vertical and horizontal directions.
The land and water determination apparatus according to claim 5. An underwater inspection apparatus for taking an image of an inspection object in water,
A propulsion unit that generates thrust to move underwater;
A detection member on which a specific image pattern is displayed;
A camera that shoots the detection member and generates image data at a first angle of view when in water and at a second angle of view wider than the first angle of view when in air; Including underwater robots,
An image acquisition unit for acquiring the image data from the camera;
A determination unit that determines whether the underwater robot is on land or underwater based on an image of a part of the detection member that is included in an image indicated by the acquired image data and changes according to an angle of view of the camera; With
Underwater inspection device. A turbidity calculator for detecting the turbidity of water based on the image of the detection member;
A control unit that controls the propulsion unit based on the turbidity detected by the turbidity calculation unit and controls a distance between the inspection object and the underwater robot;
The underwater inspection apparatus according to claim 7. When the determination result by the determination unit indicates that the underwater robot is on land, the controller further includes a control unit configured to not accept a predetermined operation on the underwater robot.
The underwater inspection apparatus according to claim 7. A detection member on which a specific image pattern is displayed is captured by a camera to generate image data,
Based on the image of the portion of the detection plate that is included in the image indicated by the image data and changes according to the angle of view when the camera is in water and in the air, the object is on land or underwater To determine whether
Land and land determination method.