JP5458270B2 - Underwater structure inspection system and image processing apparatus - Google Patents

Description

  The present invention relates to a system for inspecting an underwater structure in a harbor facility or the like and an image processing apparatus included in the system.

  Since port facilities and fishing port facilities are always exposed to harsh natural conditions, the deterioration rate is faster than ordinary buildings. In addition, a part of the structure is in water, and it is difficult to confirm deterioration from the appearance.

  In the inspection of such an underwater structure, a method in which a diver actually dives in the water and visually checks for deterioration of the structure or the like is employed.

JP 2009-210512 A

  However, in the conventional method for inspecting an underwater structure, work efficiency is significantly reduced depending on the transparency of water. In addition, such a survey involving human diving is very expensive.

  The present invention has been made in view of the above circumstances, and it is one of its purposes to provide an underwater structure inspection system and an image processing apparatus that can improve work efficiency of inspection of underwater structures and can suppress costs. To do. There is a method of taking an image of an underwater structure using sonar and investigating deterioration using this image. As a video generation apparatus for this purpose, there is one disclosed in Patent Document 1.

  The present invention for solving the problems of the above-described conventional example is an underwater structure inspection system that generates an image of an underwater structure, and includes an information processing unit and a ship that moves along the structure. An information recording unit to be mounted, and the information recording unit includes at least one set of a plurality of acoustic generators for sequentially irradiating the structure with an acoustic beam, and the reflected acoustic wave from the acoustic beam structure An imaging unit for imaging an image of a structure, a distance measuring unit for measuring a distance between an imaging object at a water depth where an acoustic generator of the imaging unit is located, and the imaging at a water depth for imaging the structure The information processing unit is a correction unit that corrects distortion caused by movement of the ship in the image contrasted by the imaging unit, and measures in advance in the sea area. Got Correction means for estimating the moving speed of the ship based on speed information and the magnitude of distortion occurring in the video, and correcting the distortion of the video using the estimated moving speed; and the corrected video Means for synthesizing a plurality of images and generating a synthesized video, and means for outputting the corrected video or the synthesized video.

  According to the present invention, since an image of an underwater structure can be obtained, the work efficiency of inspection can be improved.

It is a schematic diagram showing the example of composition of the underwater structure inspection system concerning an embodiment of the invention. It is a schematic diagram showing the example of the saddle mount of the underwater structure inspection system which concerns on embodiment of this invention. It is explanatory drawing showing the example of the expansion-contraction pole in the saddle mount of the underwater structure inspection system which concerns on embodiment of this invention. It is a block diagram showing the structural example of the information recording part of the underwater structure inspection system which concerns on embodiment of this invention. It is explanatory drawing showing the example of the information which the underwater structure inspection system which concerns on embodiment of this invention hold | maintains. It is a schematic diagram showing the example of composition of the imaging device of the underwater structure inspection system concerning an embodiment of the invention. It is a schematic diagram showing the example of the imaging range of the imaging device of the underwater structure inspection system which concerns on embodiment of this invention. It is explanatory drawing showing the example of the range imaged with the underwater structure inspection system which concerns on embodiment of this invention. It is a block diagram showing the example of a structure of the information processing apparatus which concerns on embodiment of this invention. It is a functional block diagram showing the example of the information processing apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the original image imaged with the underwater structure inspection system which concerns on embodiment of this invention. It is explanatory drawing showing the example of the range defined in the underwater structure inspection system which concerns on embodiment of this invention. It is explanatory drawing showing the example of the area | region which the underwater structure inspection system which concerns on embodiment of this invention images. It is explanatory drawing showing correction | amendment operation | movement by the information processing apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the synthesized image which the information processing apparatus which concerns on embodiment of this invention produces | generates. It is explanatory drawing showing the example of the correction | amendment operation | movement by the information processing apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the image which the information processing apparatus which concerns on embodiment of this invention outputs.

  Embodiments of the present invention will be described with reference to the drawings. As illustrated in FIG. 1, the underwater structure inspection system according to the embodiment of the present invention may or may not be equipped with the equipment mounting table 1 and the information recording unit 2 that are equipped with the ship. And an information processing device 3.

  As illustrated in FIG. 2, the saddle mount 1 includes a support portion 10, an expansion / contraction pole 11, a compressed air introduction portion 12, and an expansion / contraction control portion 13.

  The support 10 crosses the hull in the width direction and is fixed and attached to both edges on the side of the hull. And this support part 10 supports the expansion-contraction pole 11 in the position protruded outside from the hull side surface. The support unit 10 supports the telescopic pole 11 so that the telescopic pole 11 can rotate while the axial direction of the telescopic pole 11 is vertical, with the axial direction as a rotation axis. Moreover, the support part 10 can be expanded and contracted according to the length of the width direction of the hull, and can be attached to various ships.

  As shown in FIG. 3, the telescopic pole 11 is formed by nesting a plurality of cylindrical bodies 110 a, 110 b,. Here, the inner surface of the cylindrical body 110n slides on the outer surface of the sleeve 113m connected to the tip of the cylindrical body 110m having the next smallest diameter so that air or the like does not flow between the cylindrical bodies 110. The outer diameter of the sleeve 113m and the inner diameter of the cylindrical body 110n that move together are determined. Further, a ring R that surrounds the outer periphery of the cylindrical body 110 may be provided at the tip of each cylindrical body 110 for sealing.

  Further, a convex portion 111 extending in the axial direction is provided on the inner surface of each cylindrical body 110, and a concave portion 112 fitted to the convex portion is provided on the outer surface of the sleeve 113 connected to the other cylindrical body 110. At least one place is formed. The convex portion 111 and the concave portion 112 serve as means for suppressing the relative rotation of each cylindrical body 110. The height of the convex portion 111 may be made thinner than the thickness of the cylindrical body 110 (difference between the outer diameter and the inner diameter other than the concave portion and the convex portion). In FIG. 3, the sleeve 113m has a dumbbell-like shape in which both ends of a cylindrical body having a relatively small diameter are formed in a cylindrical shape having a larger diameter than that of the cylindrical body, and the heads having the recesses 112 are provided. Have. As for the outer diameter of each head, one substantially matches the inner diameter of the cylindrical body 110m, and the other substantially matches the inner diameter of the cylindrical body 110n. The main body is hollow, and the head is provided with a hole communicating with the hollow portion of the main body. Further, in the sleeve 113 shown in FIG. 3, four recesses 112 are provided in the cross direction. A ring member 117 having a hole smaller than the outer diameter of the sleeve 113 head and larger than the outer diameter of the sleeve 113 main body is attached to the ends of the cylindrical body 110n and the cylindrical body 110m. By inserting the sleeve 113 into each cylindrical body 110 via the ring member 117 and fixing the ring member 117 to the outside of the cylindrical body 110, the plurality of cylindrical bodies 110 are connected via the sleeve 113, A telescopic pole 11 is formed. In FIG. 3, the ring member 117 has flanges respectively provided on the outer periphery of the large cylindrical body (cylindrical body 110a in FIG. 3) and the outer periphery of the ring member 117 by two bolts or the like. Although fixed by fastening, the present embodiment is not limited to this.

  Of the cylindrical body 110 constituting the telescopic pole 11, the cylindrical body 110x having the smallest diameter has its lower end (hereinafter referred to as the front end side) closed by a cap. Further, a drum 114 is fixed to the tip end side, and a wire 115 is fixed to the drum 114. The other end of the wire 115 is wound around the winch 116.

  The compressed air introduction unit 12 introduces compressed air into the space inside the telescopic pole 11 from one end side (the side with respect to the distal end side) of the telescopic pole 11 in accordance with an instruction input from the expansion control unit 13. In the present embodiment, there is further provided means for extracting compressed air from the space inside the telescopic pole 11. As this means, for example, a valve communicating with the space inside the telescopic pole 11 can be used. When the compressed air is introduced, the valve is closed, and when the compressed air is extracted, the valve is opened.

  The expansion / contraction control unit 13 operates the compressed air introduction unit 12 in response to an instruction to extend the expansion / contraction pole 11 from an operator, introduces compressed air into the space in the expansion / contraction pole 11, and moves the expansion / contraction pole 11 in the axial direction. Stretch. Further, upon receiving an instruction to contract the telescopic pole 11 from the operator, the expansion / contraction control unit 13 stops the operation of the compressed air introduction unit 12 and opens the valve to release air from the space in the telescopic pole 11. Pull out. Then, the operator retracts the telescopic pole 11 by winding the wire 115 with the winch 116 in order to contract the telescopic pole 11. In the case where the winch 116 is wound by power, such as electric, the winch 116 is operated to operate the wire 115 while the expansion / contraction control unit 13 receives an instruction to contract the expansion / contraction pole 11 from the operator. Winding and the telescopic pole 11 may be contracted.

  Further, the expansion / contraction control unit 13 operates the compressed air introduction unit 12 to introduce compressed air into the space in the expansion / contraction pole 11 while maintaining the length of the expansion / contraction pole 11 without extending or contracting the expansion / contraction pole 11. doing. At this time, the amount of compressed air introduced is less than the amount introduced when the telescopic pole 11 is extended, and the lifting force of the distal end of the telescopic pole 11 due to buoyancy and the distal end of the telescopic pole 11 due to the compressed air in the telescopic pole 11 are pushed down. It is controlled to balance the power.

  In addition, as illustrated in FIG. 4, the information recording unit 2 includes a GPS device 21, a motion sensor 22, an orientation sensor 23, an imaging device 24, an acoustic sounding device 25, an interface box 31, a converter 32, a distributor 33, a first A recording device 34 and a second recording device 35 are included.

  In the present embodiment, the imaging device 24 is attached to the cylindrical body 110x on the most distal end side of the telescopic pole 11. Thereby, even if the compressed air introduced into the telescopic pole 11 leaks from between the adjacent cylindrical bodies 110, bubbles generated by the leakage do not affect the imaging of the imaging device 24. The GPS device 21 is attached to the upper end side of the telescopic pole 11 (a position protruding from the water surface).

  The GPS device 21 includes a GPS antenna 21a and a GPS positioning device 21b. In the present embodiment, at least the GPS antenna 21 a is attached to the upper end side of the telescopic pole 11. The GPS antenna 21a receives a signal from a GPS (Global Positioning System) satellite and outputs it to the GPS positioning device 21b. Based on this signal, the GPS positioning device 21b generates and outputs information (positioning information) indicating its own position and time information. Since the operation of such a GPS device 21 is widely known, detailed description thereof is omitted here.

  The motion sensor 22 is a shake meter provided with, for example, a three-axis acceleration sensor, and is attached to the distal end portion side of the telescopic pole 11, and the motion of the telescopic pole 11 at this position (predetermined X, Y, Z axes) Around) and output the measurement result as shaking information. That is, the telescopic pole 11 is shaken by the influence of waves and the influence of water flow accompanying the movement of the hull. The motion sensor 22 measures the fluctuation of the telescopic pole 11.

  The azimuth sensor 23 outputs information indicating the azimuth in the imaging direction (described later) of the imaging device 24. This azimuth sensor 23 should just output the information showing a azimuth | direction by measuring geomagnetism, such as a one-chip electronic compass, for example. The imaging device 24 emits sound waves in water, images reflected waves of the sound waves, and outputs video information (frames) obtained by the imaging. The imaging device 24 will be described in detail later.

  The acoustic sounding instrument 25 is installed at a position adjacent to the imaging device 24 of the telescopic pole 11. As a result, the acoustic sounding instrument 25 measures the distance of the imaging device 24 from the object to be photographed at the water depth. The acoustic sounding instrument 25 includes an ultrasonic generator and a receiver. The acoustic sounding instrument 25 radiates an ultrasonic pulse by the generator, receives the ultrasonic pulse directly by the receiver, and measures its transmission time. Measure the distance to the object to be photographed at a certain water depth. Then, distance information obtained by converting the measurement result into digital information is output to the first recording device 34.

  The interface box 31 receives the input of the shaking information output from the motion sensor 22 and outputs the received shaking information to the first recording device 34. The converter 32 converts the signal output from the azimuth sensor 23 into azimuth information in a predetermined format and outputs the azimuth information to the first recording device 34. The distributor 33 distributes and outputs the positioning information and time information output from the GPS device 21 to the first recording device 34 and the second recording device 35.

  The first recording device 34 receives the shake information output from the motion sensor 22 via the interface box 31, receives the positioning information and time information output from the GPS device 21 via the distributor 33, and further converts the converter. The azimuth | direction information produced | generated based on the signal which the azimuth | direction sensor 23 outputs via 32 is received. Then, the first recording device 34 records the received shaking information, positioning information, time information, and azimuth information in association with a semiconductor memory element or a storage device such as a hard disk. Further, the first recording device 34 records information on the distance from the object to be imaged output from the acoustic sounding instrument 25.

  The second recording device 35 receives the positioning information output from the distributor 33, the time information, and the video information output from the imaging device 24. The second recording device 35 records the positioning information, time information, and video information in association with each other in a semiconductor memory device or a storage device such as a hard disk. In addition, the second recording device 35 stores information on the speed of sound in water measured in advance in a place (sea area) where an object is imaged.

  In the present embodiment, time information by GPS, shaking information, positioning information, azimuth information, information on the distance to the imaging target, and video information are sequentially output over time. When the first recording device 34 of the present embodiment receives the input of each of these pieces of information, the time information at the time of the input (by a clock (not shown) built in the first recording device 34). As shown in FIG. 5A, these pieces of information are recorded in association with timed time information (hereinafter referred to as time information by the first recording device). Since positioning information is output together with time information from GPS, in FIG. 5A, time information from GPS and positioning information are recorded in association with common time information.

  Further, conceptually, in the second recording device 35, as shown in FIG. 5B, for the output video information, the GPS time obtained when the video information (frame) is input. The information and the time information at the time of the input (time information measured by a clock (not shown) built in the second recording device 35) are held in association with each other. Thereby, each information recorded on the 1st recording device 34 and the 2nd recording device 35 is synchronized via the time information by a 1st recording device, and the time information by GPS (it is linked | related with common time information). Information can be taken out), and the information received at the same time can be obtained. For example, positioning information and video information can be synchronized by comparing GPS time information recorded in the first recording device 34 and the second recording device 35, respectively. For example, the difference between the time information recorded by the GPS recorded in the first recording device 34 and the time information recorded by the first recording device when the time information recorded by the GPS is recorded. After converting the time information by the first recording device associated with the shaking information, the direction information, the information on the distance to the imaging target, etc. into a value equivalent to the time information by GPS using the calculated difference, 2 Compared with the time information by GPS recorded in the recording device 35, it can be synchronized with the video information.

  Here, the imaging device 24 will be described in detail. The imaging device 24 is a so-called sonar, and includes a plurality of acoustic generators 41, acoustic receivers 42, and a contrast unit 43 as shown in FIG. Here, the acoustic generators 41 are arranged in K groups (N and K are integers of 2 or more, respectively) with N as a set in a predetermined arrangement direction (θy axis direction).

  Each sound generator 41 emits a pulse sound directed to spread in a direction perpendicular to the arrangement direction. Specifically, as shown in FIG. 7, a box-shaped region extending in the direction of sound emission of the sonar is obtained by dividing N × K pieces (the number of sound generators 41) in the arrangement direction of the sound generators 41. Consider N × K substantially plate-like regions R. At this time, for each region R, the pulse sound wave from each acoustic generator 41 is emitted as an acoustic beam.

  The acoustic receiver 42 receives the reflected wave of the acoustic beam emitted from the acoustic generator 41. The acoustic wave receiver 42 obtains information on the distance to the object based on the time from when the acoustic generator 41 radiates the acoustic beam until the reflected wave is received. Furthermore, the acoustic receiver 42 obtains information on the intensity (or amplitude) of the reflected wave. Then, the acoustic receiver 42 outputs, for each acoustic generator 41, information on the distance to the object measured by the reflected wave of the emitted sound wave and the intensity of the reflected wave.

  As shown in FIG. 8, the contrast unit 43 displays a two-dimensional image with the arrangement direction of the sound generators 41 as one axis (θy axis) and the distance to the object as another axis (r axis). Generate. That is, on the line along the r-axis corresponding to the sound generator 41 that radiates the sound wave, the pixel at the position corresponding to the reception time of the reflected wave is set to the pixel value of the luminance corresponding to the intensity of the received reflected wave. Then, video information (frame) is generated and this video information is output.

  In the present embodiment, a plurality of sound generators 41 are arranged. However, in order to prevent the image from being disturbed by interference with the sound beam generated by the adjacent sound generator 41, the following control is performed. ing. In other words, in the present embodiment, as shown in FIG. 7, the N consecutive acoustic generators 41 are grouped. A permutation of numerical values from 1 to N is defined as P1, P2,... PN (for example, P1 = 1, P2 = 5, P3 = 2...). Then, each set P (i mod N) -th acoustic generator 41 emits an acoustic beam all at once, and then repeatedly performs control such that i is incremented by 1 after the interval Δt. As a result, the P1-th to PN-th sound generators 41 in each group emit sound waves in this order, and the P1-th sound generator 41 emits sound waves. By performing this control while moving the ship along the object, an image obtained by scanning the object can be obtained. When attention is paid to one of the sound generators 41, a period in which the noticed sound generator 41 repeatedly emits an acoustic beam is T = Δt · N. In the following description, when attention is paid to one sound generator 41, a line on the subject scanned by the sound wave of the noticed sound generator 41 is L.

  Specifically, in an example of the present embodiment, N = 8 and K = 12, and the G generator (G = 1, 2,... K) acoustic generators 41 are respectively “1, 5, 2”. , 6,3,7,4,8 "in order of the interval Δt to emit acoustic beams.

  Next, the operation of the information processing apparatus 3 will be described by taking as an example a case where an image of a planar underwater structure such as a quay is taken as an object.

  As illustrated in FIG. 9, the information processing apparatus 3 according to the present embodiment includes a control unit 51, a storage unit 52, and an output unit 53. Here, the control unit 51 is a CPU (Central Processing Unit), and is a program control device that operates according to a program stored in the storage unit 52. In the present embodiment, the control unit 51 is stored in the second recording device 35 and information on the orientation, shaking, positioning, and distance to the object to be photographed that are stored in the first recording device 34 of the information recording unit 2. Image information is processed, and image information (processed image information) as a result of the processing is output. Specifically, in the present embodiment, the control unit 51 corrects sawtooth distortion caused by the sound generators 41 sequentially radiating sound waves and distortion caused by the shaking of the ship. Details of the processing of the control unit 51 will be described later.

  The storage unit 52 includes a disk device such as a memory device or a hard disk. The storage unit 52 holds a program executed by the control unit 51. The storage unit 52 also operates as a work memory for the control unit 51.

  The output unit 53 outputs image information processed in accordance with an instruction input from the control unit 51. The output unit 53 may be, for example, a communication device such as a display, a printer, or a network interface that outputs an image to another computer system.

  Here, the contents of the processing of the control unit 51 will be described. Functionally, the control unit 51 includes a reading unit 61, a region demarcating unit 62, an original image correcting unit 63, a synthesizing unit 64, and a moving distortion correcting unit 65, as shown in FIG.

  The reading unit 61 reads each piece of information recorded in the first recording device 34 and the second recording device 35 of the information recording unit 2 and outputs the information to the area defining unit 62. The video information that the reading unit 61 reads from the second recording device 35 is an original video that the imaging device 24 sequentially outputs. Here, each of the original images is called a frame. One frame includes an image contrasted by the reflected wave of the acoustic beam radiated from each of the acoustic generators 41 of the plurality of acoustic generators 41 included in the imaging device 24. Therefore, this frame includes, for example, an image obtained by capturing a part as shown in FIG. 11B in the quay range illustrated in FIG.

  The area demarcating unit 62 obtains one of the video information (frame) recorded by the second recording device 35 (referred to as the i-th frame Fi) via the reading unit 61, and images the subject in the frame Fi. The detected range is detected by, for example, contour detection processing using a luminance difference between pixels. Then, a partial region for composition is defined in the range in which the subject is imaged in the frame Fi. Here, the partial areas are, for example, the width center part in the movement direction of the imaging device 24 in the range where the subject is imaged (range A1 in FIG. 12A), and the front end part in the movement direction (range A2 in FIG. 12B). ) Or a predetermined range such as a rear end in the moving direction (range A3 in FIG. 12C), or a range designated in advance by the user.

  The area demarcating unit 62 accumulates and stores information (coordinate information) representing the demarcated partial area in the storage unit 52 in association with information (for example, number i) specifying the original frame. Then, the area demarcating unit 62 updates and stores information representing a partial area for composition while incrementing i by “1”.

  The original video correction unit 63 sequentially takes out the frames stored in the storage unit 52 as processing targets, calculates the luminance distribution of the video, and performs luminance correction so that the luminance distribution becomes uniform. Then, the original video correction unit 63 overwrites the original frame with the corrected frame and stores it in the storage unit 52.

In the present embodiment, as illustrated in FIG. 13, the imaging device 24 is arranged so that the acoustic beam strikes the subject obliquely. Therefore, even if the shortest distance d from the imaging device 24 to the subject is constant, the image portion on the near side in the traveling direction of the ship and the image portion on the far side in the traveling direction are imaged as different distances r1 and r2. In the following description, the water depth direction of the subject is the Y axis, the width direction of the subject is the X axis, and the axis perpendicular to the surface of the subject is the Z axis. In this case, as shown in FIG. 14, the position of the sound generator 41 is S (x, y, d), and the point where the sound beam (center) emitted from the sound generator 41 hits the subject is P (x + dx, y). −dy, 0), and the perpendicular foot from S to the subject is S ′, and the distance between P and S ′ is Rw, the distance R0 between S and P is used,
Rw = √ (R0 ² −d ² )
Can be written.

The distance dx between the point P and the point S ′ in the X-axis direction is
dx = √ (Rw ² −dy ² )
It becomes. Note that dy is an angle representing the radiation direction of the acoustic beam of the acoustic generator 41 at the point S, where θ is
dy = R0 · sinθ
It can be expressed as. The original image correction unit 63 according to the present embodiment reads the positioning information held by the second recording device 35 in association with the processing target frame, and associates with the same positioning information as the read positioning information. The azimuth | direction information currently recorded on 1 recording device 34 is read. Then, the angle θ is determined based on this orientation information and the known positioning information of the target structure.

  In addition, the original image correction unit 63 reads the shake information recorded in the first recording device 34 in association with the same positioning information as the read positioning information, and the frame to be processed is imaged from this shake information. The rotation angle ωx around the ship traveling direction (X-axis direction) in the radiation direction of the acoustic beam from the imaging device 24 and the rotation angle ωy around the vertical direction (Y-axis direction) are obtained. Then, information that defines the angle of view of the processing target frame is calculated.

  The original image correction unit 63 assumes that the average distance to the subject in the processing target frame is the distance d in both the image portion on the near side in the traveling direction and the image portion on the far side in the traveling direction. Geometric correction is performed so that the angle becomes the angle of view when facing the corner. As a result, the frame held in the storage unit 52 is corrected to become an image when facing the subject. Here, since a well-known process is used for the geometric correction, a detailed description thereof is omitted here. Here, it is assumed that the subject such as a quay, a water bottom or a part of a hull can be regarded as a substantially flat surface at least locally, and that a ship or the like equipped with the imaging device 24 is moving along the surface of the subject. The distance d to the subject is corrected using distance information obtained from the acoustic sounding instrument 25.

  In addition, the original image correcting unit 63 corrects the information representing the partial area stored in the storage unit 52 in association with the information for specifying the geometrically corrected frame in accordance with the geometric correction for the image.

  The synthesizing unit 64 sequentially selects the frames held in the storage unit 52 as the target frame, and performs a video synthesizing process between the target frame and a frame other than the target frame to generate a synthesized audio video.

  According to an example of the present embodiment, the synthesizing unit 64 uses the frame of interest as the frame Fi, and the synthesized audio video G synthesized so far (in the case of the first frame, the synthesized audio video G is used as it is. The frame Fi-j input in the past and the frame Fi + k (j, k = 1, 2,...) Stored subsequent to the frame of interest Fi are selected by the designated number. . Then, the same video part as the video part included in the partial area associated with the target frame Fi is searched from the selected frame. This detection can be realized by using a correlation calculation of the video part (for example, by summing up absolute values of pixel value differences and extracting a range where the absolute value is minimized).

  For example, when three video parts are synthesized, Fi-1 (included in the synthesized audio video G synthesized so far), the frame of interest Fi, and the frame Fi + 1 stored next to the frame of interest. The common video portion may be searched for and synthesized to update the synthesized audio video G, or the common video portion may be searched for and synthesized from Fi, Fi + 1, Fi + 2 It may be updated. The generated / updated synthesized audio video G is stored in the storage unit 52.

  The synthesized audio video G after being synthesized in this way is as described below. That is, as already described, in the present embodiment, each of the acoustic generators 41 in each set performs control to sequentially emit the acoustic beam, and thus the Pnth acoustic generator 41 emits the acoustic beam. Until the Pn + 1th acoustic generator 41 emits an acoustic beam (during time Δt). For this reason, when the sound generator 41 emits an acoustic beam in the traveling direction of the ship, the subject that is supposed to be contrasted linearly by the reflected wave of the acoustic beam emitted by each acoustic generator 41 in the same set The synthesized audio video G is imaged with an oblique distortion. Since an obliquely distorted image is obtained in each group, a sawtooth image is obtained by repeating each group. That is, the synthesized audio image G is an image in which an end portion in the X-axis direction (the ship moving direction) is distorted in a sawtooth shape as illustrated in FIG.

Therefore, the moving distortion correction unit 65 performs processing for correcting the sawtooth distortion. Specifically, the moving distortion correction unit 65 reads the information on the speed of sound stored in the second recording device 35 through the reading unit 61 as the acoustic beam propagation velocity ν. Further, the movement distortion correction unit 65 reads out the synthesized audio video G from the storage unit 52. Then, the maximum pixel value from the tip to the root of the sawtooth distortion occurring in the synthetic audio image G is examined. The number of pixels is λ. At this time, if the relative speed between the ship and the subject is v,
λ / ((ν−v) · N) = Δt
The movement distortion correction unit 65 solves this for v v = ν−λ / (Δt · N).
Is calculated. This v calculated by the movement distortion correction unit 65 is a relative speed for canceling the protrusion of the sawtooth portion.

  The moving distortion correction unit 65 performs synthesis on a line along the X axis corresponding to an image picked up by the i-th acoustic generator 41 in each set, where T is the interval at which a certain acoustic generator 41 emits an acoustic beam. The pixel of the audio image G is moved in the direction opposite to the moving direction of the ship (imaging device 24) by v × T × (i / N) (FIG. 16). Specifically, among periodic sawtooth distortions generated in the synthesized audio video G, a pixel group on the synthesized audio video G along the X axis that is shifted most in the movement direction of the ship on the X axis is represented by v. Move by * T * (N / N) = v * T. Hereinafter, after the movement, a pixel group on the synthesized audio image G along the Y axis that is further shifted in the moving direction of the ship on the X axis is represented by v × T × (i / N) (where i = N−1). ) Is repeatedly performed until i = 1 while decrementing i by “1”. As a result, a synthesized audio image G in which the sawtooth distortion is corrected is obtained. The output unit 53 outputs the synthesized audio video G that has been corrected by the movement distortion correction unit 65.

  The output unit 53 may perform the following processing using the positioning information output from the GPS device 21. In other words, the output unit 53 obtains the positioning information at the time of recording start of the video information and the positioning information at the end of recording of the video information, so that the width of the synthesized audio video G in the X-axis direction becomes a predetermined scale. The audio video G may be corrected for enlargement / reduction.

  The output unit 53 displays the value of the X axis of the synthetic audio video G and the positioning information output from the GPS device 21 in association with each other. Further, the output unit 53 may synthesize and display a separately prepared video of the water surface in alignment with the synthesized audio video G. Specifically, the output unit 53 includes a ground part image that associates a caisson number preset for each caisson and coordinate information on the image corresponding to each caisson number, and a caisson corresponding to each caisson number and each caisson number. The input of the caisson position information associated with the positioning information (positioning information at the end of each caisson) is accepted. Here, the caisson is a rectangular member used for the construction of an underwater structure, and here, the caisson is arranged so that the end thereof extends in the water depth direction.

  The output unit 53 refers to the positioning information related to the X-axis value of the synthetic audio video G, and the X-axis value pair of the synthetic audio video G corresponding to the positioning information at both ends of the caisson corresponding to each caisson number Get. Then, the output unit 53 performs an enlargement / reduction process on the video of the upper part of the caisson corresponding to each caisson number so that the video of the upper part of the caisson can be synthesized between the paired X-axis values obtained by the above method. And synthesize at a position above the water surface. The enlargement / reduction processing and composition may be performed for each video of the caisson corresponding to the caisson number, or may be performed for the entire image. By this processing, the video output by the output unit 53 is as shown in FIG.

  Further, the output unit 53 synthesizes the design drawing with the synthesized audio video G (in this case, the line on the design drawing is synthesized with the video, and the synthesized audio video G is synthesized so that the portion without the line remains. ) Is also good. Also in this case, the output unit 53 uses the caisson position information in which the caisson number and the caisson positioning information corresponding to each caisson number (positioning information at the end of each caisson) are associated, and the X-axis of the synthesized audio video G With reference to the positioning information related to the value, a pair of X-axis values of the synthesized audio video G corresponding to the positioning information at both ends of the caisson corresponding to each caisson number is obtained. Then, the design drawing is enlarged or reduced so that both ends of the range corresponding to the caisson number on the design drawing (a part of the design drawing corresponding to each caisson) match the paired X-axis values obtained by the above method. Process and synthesize. Also in this case, the enlargement / reduction processing and composition may be performed for each part of the design drawing corresponding to the caisson number, or may be performed for the entire design drawing. With this processing, the video output by the output unit 53 is as shown in FIG.

[Operation]
An underwater structure imaging method using the system of the present embodiment will be described next. The operator adjusts the length of the telescopic pole 11, sets the position of the imaging device 24 to the water depth Y1, and captures an image while moving the ship along the underwater structure to be subjected to deterioration inspection. In other words, the imaging device 24 is supported by the saddle mount 1 at the depth (water depth) Y1 for imaging the underwater structure. Then, at this depth (water depth) Y1, the video imaged by the imaging device 24 is recorded in the information recording unit 2, and the information processing device 3 generates the synthesized audio video G1 from the recorded video image.

  In addition, the operator changes the length of the telescopic pole 11 to set the position of the imaging device 24 at the water depth Y2, and captures an image while moving the ship along the underwater structure to be subjected to the deterioration inspection. As a result, the video imaged at the depth Y2 is recorded in the information recording unit 2, and the information processing device 3 generates the synthesized audio video G2 from the recorded video image.

  In the same manner, imaging is performed while changing the water depth of the imaging device 24 to Y3, Y4,... To obtain corresponding synthetic audio images G3, G4,.

  In the case of this example, each water depth is determined so that there is an overlapping portion in each image captured at the water depth Yi and Yi + 1. And the information processing apparatus 3 synthesize | combines each synthetic | combination audio video G1, G2, ... using the correlation in the said duplication part.

  In addition, although an example in which imaging is performed while moving the ship along the positive direction of the X axis has been described here, an image when the imaging device 24 is placed at the same water depth is displayed as a normal image of the ship along the X axis direction. The synthesized audio video G may be obtained by synthesizing each video and capturing both when moving in the negative direction and when moving in the negative X-axis direction.

  As a result, the worker can examine cracks and the like generated in the underwater structure that is the subject while referring to the synthesized audio image.

  DESCRIPTION OF SYMBOLS 1 Saddle mounting base, 2 Information recording part, 3 Information processing apparatus, 10 Support part, 11 Telescopic pole, 12 Compressed air introduction part, 13 Telescopic control part, 21 GPS apparatus, 22 Motion sensor, 23 Direction sensor, 24 Imaging apparatus, 25 Acoustic sounding device, 31 interface box, 32 converter, 33 distributor, 34 first recording device, 35 second recording device, 41 acoustic generator, 42 acoustic receiver, 43 contrast unit, 51 control unit, 52 storage unit , 53 output unit, 61 reading unit, 62 region demarcating unit, 63 original image correcting unit, 64 combining unit, 65 moving distortion correcting unit, 110 cylindrical body, 111 convex unit, 112 concave unit, 113 sleeve, 114 drum, 115 wire 116 winch, 117 ring member.

Claims (3)

An underwater structure inspection system for generating an image of an underwater structure,
Including an information processing unit and an information recording unit mounted on a ship moving along the structure,
The information recording unit
An imaging means comprising at least one set of a plurality of acoustic generators for sequentially irradiating the structure with an acoustic beam, and imaging an image of the structure by a reflected wave from the acoustic beam structure;
Distance measuring means for measuring the distance to the object to be photographed at the water depth where the acoustic generator of the imaging means is located;
A saddle mount that supports the imaging means at a water depth for photographing the structure;
With
The information processing unit
Correction means for correcting distortion caused by movement of the ship in the image contrasted by the imaging means, information on sound speed obtained by measuring in advance in the sea area, and magnitude of distortion occurring in the image Correction means for estimating the moving speed of the ship based on the image and correcting the distortion of the image using the estimated moving speed;
Means for generating a composite image by combining a plurality of the corrected images;
Means for outputting the corrected video or the synthesized video;
An underwater structure inspection system characterized by comprising: An information recording unit that generates and records an image of an image of a structure in water, and includes at least one set of a plurality of acoustic generators that sequentially irradiate the structure with an acoustic beam, the acoustic beam structure Connected to an information recording unit comprising imaging means for contrasting an image of a structure by reflected waves from the light source, and means for measuring a distance from a photographing object at a water depth where an acoustic generator of the imaging means is located ,
Correction means for correcting distortion caused by movement of the ship in the image contrasted by the imaging means of the information recording unit, and information on sound speed obtained by measuring in advance in the water where the sound generator is located; , estimates the movement speed of the ship on the basis of the magnitude of the distortion that occurs to the image, and correcting means for correcting distortion of the image using the moving speed and the estimated,
Means for generating a composite image by combining a plurality of the corrected images;
Output means for outputting the corrected video or the synthesized video;
An image processing apparatus comprising: The image processing apparatus according to claim 2,
The output means enlarges / reduces a prepared image of the water top or the image of the design drawing according to the scale of the corrected image, and outputs the image of the water top or the design drawing subjected to the enlargement / reduction processing. An image processing apparatus characterized in that the corrected video is synthesized and output.

Images