Bridge underwater structure column-holding type obstacle-surmounting detection platform and detection method

Abstract

This invention relates to a bridge underwater structure column-hugging obstacle-crossing inspection platform and inspection method. The inspection platform includes a frame body, an obstacle-crossing mechanism, a binocular camera inspection device, a ring drive track mechanism, and a diving and rising mechanism. This platform is an obstacle-crossing inspection platform for underwater bridge components. For components with known defects, the inspection platform, equipped with a binocular camera inspection device, completes image acquisition of a specified area or the entire area of ​​the underwater bridge component. At the same time, the inspection platform uses a column-hugging method to perform high-precision and stable inspection of underwater bridge piers, which can adapt to changes in the cross-sectional dimensions of the piers and achieve all-round inspection of the piers at different heights and angles.

Description

TECHNICAL FIELD

[0001] The application relates to a bridge underwater structure column-holding obstacle-surmounting detection platform and a detection method. BACKGROUND

[0002] Current underwater structure detection mainly includes manual detection and ROV detection, and the two methods can only complete qualitative detection of diseases and cannot provide actual size information of the diseases. A method based on a sonar and an optical camera can complete quantitative detection of the diseases, but still cannot meet the requirement of three-dimensional topography reconstruction of underwater components of a bridge with diseases. Due to the scattering and refraction of laser in underwater measurement, the three-dimensional reconstruction of underwater structures is mainly realized by using a sonar and an optical camera, and the optical camera can be used for three-dimensional topography reconstruction of a specific component or the whole underwater structure due to higher image resolution, so as to provide intuitive and reliable data support for disease area distribution, positioning of difficult and key diseases and overall component degradation.

[0003] In addition, the poor underwater imaging quality is greatly affected by the imaging resolution of the camera. The resolution of the camera carried by a manual worker or an ROV underwater robot is generally low, and the image resolution is usually only 800*1000. The low resolution leads to blurred image features, and misjudgment is easily caused when distinguishing underwater foreign matters, diseases and component texture information. In the aspect of three-dimensional topography detection of components by using an optical camera, due to the complexity of the surface features of underwater structures and the continuous change of the water environment, it is difficult to guarantee the accuracy of the overall three-dimensional point cloud data after multiple measurements by simply relying on a manual diver to carry an optical camera, so it is necessary to first design a stable underwater mounting platform capable of mounting a camera to complete image acquisition of the target surface of the underwater component; secondly, how to establish a component three-dimensional topography reconstruction facing the underwater environment and complete conversion of the planar image data to the three-dimensional point cloud data in combination with the designed underwater mounting platform is another important work. SUMMARY

[0004] The application provides a bridge underwater structure column-holding obstacle-surmounting detection platform and a detection method, which can realize high-precision and stable detection of a bridge underwater pier by adopting a column-holding mode, can adapt to changes in the cross-sectional size of the pier and can realize omnidirectional detection of the pier at different heights and different angle positions.

[0005] The application adopts the technical scheme that

[0006] The application adopts the technical scheme that

[0007] The rack body comprises two base structures arranged oppositely, two connecting supports connected between the two base structures, the two connecting supports being arranged in parallel and having a distance between adjacent connecting supports; each connecting support is in the shape of a regular polygon, and the base structures are symmetrically mounted on the connecting supports, i.e., each base structure is connected to two connecting supports on the same side;

[0008] The obstacle-crossing mechanism comprises a plurality of obstacle-crossing mechanisms mounted at the contact positions of the connecting supports and the base structures;

[0009] An annular driving guide rail mechanism is further arranged on the rack body, i.e., an annular driving guide rail mechanism is arranged between the two base structures and arranged on the surface of the lower connecting support, a binocular camera detection device for detecting the bridge pier to be detected is arranged on the annular driving guide rail mechanism, and the annular driving guide rail mechanism is combined with the obstacle-crossing mechanism to adapt to the circumferential size of the bridge pier to be detected;

[0010] A diving and ascending mechanism is mounted at the bottom of each base structure to provide power for the diving and ascending of the detection platform;

[0011] As a further preferred embodiment of the present application, the base structure comprises an upper base, an intermediate base and a lower base arranged in sequence from top to bottom, and the upper base, the intermediate base and the lower base are arranged in parallel with each other;

[0012] A plurality of hollow aluminum pipes are arranged between the adjacent upper base and intermediate base and the intermediate base and lower base in the vertical ground direction to form supports;

[0013] As a further preferred embodiment of the present application, the obstacle-crossing mechanism comprises a tripod, three obstacle-crossing wheels, a horizontal connecting rod, a vertical connecting rod and a tension spring,

[0014] The two horizontal connecting rods are connected by two vertical connecting rods to form a parallelogram structure, and the parallelogram structure is deformable, and the connecting positions of the horizontal connecting rod and the vertical connecting rod are connected by an adapter connecting rod; two parallelogram structures are included, the planes of each parallelogram structure are perpendicular to the ground, and the two parallelogram structures are arranged in parallel;

[0015] The center of the tripod is provided with a support shaft, the tripod rotates on the support shaft, the parallelogram structure formed above has one end of the horizontal connecting rod extending outward, and the extension ends of the horizontal connecting rods of the two parallelogram structures are connected to the two ends of the support shaft, respectively;

[0016] The obstacle-crossing wheels are rotatably connected at the three vertices of the tripod;

[0017] In the two parallelogram structures arranged oppositely, a spring connecting plate is arranged between the two horizontal connecting rods below, another spring connecting plate is arranged between the two vertical connecting rods away from the tripod, and a plurality of tension springs are connected between the two spring connecting plates.

[0018] The obstacle-crossing mechanism installed on the upper connecting support, each of the lower horizontal connecting rods is fixed on the surface of the upper base through the wheel group support;

[0019] The obstacle-crossing mechanism installed on the lower connecting support, each of the upper horizontal connecting rods is fixed on the bottom surface of the lower base through the wheel group support;

[0020] As a further preferred embodiment of the present application, the diving and ascending mechanism comprises a floating support plate, a mounting profile and a plurality of propellers, the floating support plate is connected below the lower base through a plurality of hollow aluminum pipes, and the floating support plate is arranged parallel to the lower base;

[0021] A plurality of mounting profiles arranged in parallel are fixed on the surface of the floating support plate, each of the mounting profiles extends out of the floating support plate, and a propeller is installed at each end of each of the mounting profiles;

[0022] As a further preferred embodiment of the present application, the ring-shaped driving track mechanism comprises a circular guide rail, a synchronous belt, a synchronous belt wheel, a guide wheel, a motor mounting seat and a motor,

[0023] The synchronous belt is arranged on the outer circumferential surface of the circular guide rail, two circular surfaces of the circular guide rail parallel to the ground are respectively attached to the wheel surfaces of the guide wheels, the two guide wheels are fixed on the guide wheel mounting seat, the guide wheel mounting seat is in a U-shaped form, and the two guide wheels are respectively arranged on the two vertical parts of the U-shaped guide wheel mounting seat; the surface of the synchronous belt is engaged with the synchronous belt wheel, the motor mounting seat is in an L-shaped form, the horizontal part of the L-shaped form is overlapped with the vertical part of the guide wheel mounting seat located above, the motor is installed on the motor mounting seat, and the motor shaft is connected with the synchronous belt wheel through a coupling, that is, the motor drives the synchronous belt wheel to realize the ring-shaped movement on the synchronous belt through the coupling;

[0024] The circular guide rail is installed on the surface of the lower base through a guide rail support seat;

[0025] A binocular camera detection device is installed on the motor mounting seat;

[0026] As a further preferred embodiment of the present application, the circular guide rail is formed by splicing two semicircular guide rails, and the splicing part of the two semicircular guide rails is fixed through a guide rail connecting plate;

[0027] As a further preferred embodiment of the present application,

[0028] The connecting support is arranged in a regular hexagonal form;

[0029] The tension spring in the obstacle-crossing mechanism comprises two;

[0030] In the diving and ascending mechanism, two mounting profiles arranged in parallel are fixed on the surface of each floating plate support plate, and a propeller is installed at each end of each of the mounting profiles.

[0031] A detection method based on the bridge underwater structure column type obstacle detection platform, specifically comprising the following steps:

[0032] Step S1: calibrate the single industrial camera world coordinate system in the water-free environment;

[0033] Step S2: calibrate the world coordinate of the binocular industrial camera in the underwater environment;

[0034] Step S3: the detection platform is longitudinally dived to a specified distance underwater;

[0035] Step S4: collect data of multiple measuring points at the specified position;

[0036] Step S5: point cloud calculation is performed on multiple measuring points;

[0037] Step S6: rotation and translation matrix calculation is performed on multiple measuring points;

[0038] Step S7: the detection platform rotates to complete the point cloud splicing of each measuring point at the ring;

[0039] Step S8: the detection platform continues to longitudinally dive to another specified distance underwater, and steps S3-S7 are repeated to complete point cloud calculation and splicing at each depth;

[0040] Step S9: ring point cloud data at each underwater travel stage is spliced to complete the overall three-dimensional topographic measurement of the bridge pier to be detected;

[0041] As a further preferred embodiment of the present application,

[0042] In step S1, the method for calibrating the world coordinate system of the single industrial camera in the water-free environment specifically comprises the following steps: firstly, the world coordinate system is calibrated by using concentric circular ring type coding mark points for feature point extraction; a series of images of the surface of the bridge pier to be detected containing the coding points are shot by using a single industrial camera, the mark point recognition and the center positioning of the mark points are completed, and the shot images are preprocessed, edge extracted, feature recognized and screened, and the coding points are decoded; then, the three-dimensional coordinate reconstruction of each coding point on the surface of the bridge pier to be detected is completed, and the spatial three-dimensional coordinate values are optimized through three-dimensional coordinate reconstruction;

[0043] In step S2, the world coordinate of the binocular industrial camera in the underwater environment is calibrated by using a chessboard calibration method;

[0044] In the repeated process of steps S3-S7, the detection platform repeats the image collection at each stage with the same descending distance, and the turning direction of the detection platform in adjacent stages is opposite.

[0045] Through the above technical scheme, compared with the prior art, the present application has the following beneficial effects:

[0046] 1. The detection platform provided by the present application adopts a column-holding structure and can adapt to bridge piers with different cross sections;

[0047] 2. The detection platform provided by the present application uses a floating mechanical mechanism and can directly perform detection underwater, and is equipped with an obstacle-crossing mechanism symmetrically installed in the upper and lower and left and right four regions of the entire platform, thereby maintaining the stability of the entire detection platform during detection of the bridge pier. BRIEF DESCRIPTION OF DRAWINGS

[0048] The present application will be further described below in combination with the drawings and examples.

[0049] Figure 1 is a schematic diagram of the overall structure of the preferred embodiment provided by the present application;

[0050] Figure 2 is a schematic diagram of the structure of the preferred embodiment provided by the present application regarding the rack body and the diving and ascending mechanism;

[0051] Figure 3 is a schematic diagram of the structure of the preferred embodiment provided by the present application regarding the obstacle-crossing mechanism;

[0052] Figure 4 is a schematic diagram of the structure of the preferred embodiment provided by the present application regarding the binocular camera detection device;

[0053] Figure 5 is a schematic diagram of the structure of the preferred embodiment provided by the present application regarding the ring-shaped driving track mechanism;

[0054] Figure 6 is a schematic diagram of the structure of the preferred embodiment provided by the present application regarding the guide wheel mounting seat and the motor mounting seat;

[0055] Figure 7 is a top view of the binocular camera arrangement of the preferred embodiment provided by the present application;

[0056] Figure 8 is a flowchart of the detection scheme based on the preferred embodiment provided by the present application;

[0057] Figure 9 is the coding point and its size ratio involved in the detection method provided by the present application;

[0058] Figure 10 is a schematic diagram of the calibration of the binocular industrial camera underwater;

[0059] Figure 11 is a schematic diagram of the detection method provided by the present application for collecting each measuring point of the underwater bridge pier to be detected;

[0060] Figures 12a-12bThe detection method provided by the application is a schematic diagram of position calibration of a water point and conversion of underwater point cloud data.

[0061] In the figure: 1 is an obstacle wheel, 2 is a tripod, 3 is a support shaft, 4 is a horizontal connecting rod, 5 is a vertical connecting rod, 6 is a switching connecting rod, 7 is a spring connecting plate, 8 is a tension spring, 9 is a middle base, 10 is an upper base, 11 is a lower base, 12 is a hollow aluminum pipe, 13 is a wheel set support, 16 is a floating body support plate, 18 is a circular guide rail, 19 is a synchronous belt, 20 is a guide wheel, 21 is a guide wheel mounting seat, 22 is a motor mounting seat, 23 is a synchronous belt wheel, 24 is a guide rail support seat, 25 is a guide rail connecting plate, 26 is a shaft coupling, 27 is a motor, 28 is a cavity bottom plate, 29 is a cavity, 31 is a cavity top plate, 32 is an industrial camera, 33 is a camera lens, 35 is transparent organic glass, 37 is a connecting bracket, 38 is a mounting profile, and 39 is a propeller. DETAILED DESCRIPTION

[0062] The application will be further described in detail with reference to the drawings. In the description of the present application, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and "first", "second" and the like do not represent the importance of the parts, and therefore cannot be understood as limiting the present application. The specific dimensions used in the embodiments are only for the purpose of illustrating the technical solutions and do not limit the protection scope of the present application.

[0063] As pointed out in the background art, the existing underwater structure detection cannot directly contact or directly face the bridge pier disease position, resulting in only qualitative detection of the bridge pier disease, and the specific size cannot be confirmed. Even if optical sonar and other methods are used to quantitatively detect the disease, due to the underwater bridge pier structure, the light scattering and refraction are affected, and the accuracy of the measurement cannot be guaranteed. At the same time, how to establish a component three-dimensional topography facing the underwater environment, and combine the designed underwater carrying platform to complete the conversion of the planar image data to three-dimensional point cloud data, becomes another important goal of obtaining accurate results.

[0064] Therefore, the present application provides a bridge underwater structure column-holding type obstacle-crossing detection platform and detection method, which can directly face the disease part of the bridge pier underwater, and the column-holding type can adjust the detection position of the detection platform on the bridge pier in real time, and at the same time, a component three-dimensional topography facing the underwater environment is established. First, the specific detection platform is as follows Figure 1As shown, it is a whole structure schematic diagram of the present application, which includes a rack body, an obstacle crossing mechanism, a binocular camera detection device, a ring-shaped driving track mechanism and a diving and ascending mechanism; the obstacle crossing mechanism, the binocular camera detection device, the ring-shaped driving track mechanism and the diving and ascending mechanism are all installed on the rack body.

[0065] The current pile type pier is still the main design form of underwater structure, which has variable cross-section design (small cross-section suddenly changes to large cross-section), and the cross-section size of the pier is generally different from that of the pile foundation by 20-30 cm; in addition, the existing service underwater structure has serious diseases such as necking, and there is also the requirement of variable cross-section (large cross-section suddenly changes to small cross-section) in the diving operation process of the detection platform; some seriously damaged components also have variable cross-section (small cross-section suddenly changes to large cross-section) after being reinforced by increasing the cross-section or pipe piece, therefore, the present application designs a ring-shaped driving track mechanism combined with an obstacle crossing mechanism which can adapt to the circumference size of the pier; the binocular camera detection device is installed on the ring-shaped driving track mechanism, which uses double-row array light source and can be moved to the corresponding pier disease position by the driving of the motor of the ring-shaped driving track mechanism, thereby performing high dynamic and high precision detection on the pier within a certain range.

[0066] The diving and ascending mechanism in the present application provides power through the propeller 39, so as to realize the diving and ascending action of the underwater detection platform and ensure the traveling power of the detection platform in water.

[0067] Next, each part will be described in detail, Figure 2 As shown, the rack body includes two base structures arranged oppositely, two connecting supports 37 are connected between the two base structures, the two connecting supports are arranged in parallel and have a distance between adjacent connecting supports, and the connecting supports are arranged to reinforce the rack body; each connecting support is in the shape of a regular polygon, and the base structures are symmetrically installed on the connecting supports, that is, each base structure is connected to two connecting supports on the same side; the base structure includes an upper base 10, an intermediate base 9 and a lower base 11 which are sequentially arranged in a stack from top to bottom, and the upper base, the intermediate base and the lower base are arranged in parallel with each other; in the vertical ground direction, the adjacent upper base and intermediate base and the intermediate base and lower base are supported by a plurality of hollow aluminum pipes 12. After experiments, the connecting supports are arranged in the shape of a regular hexagon, which is the most stable structure, and the fixed position of the base structure is the intersection position of two adjacent sides of the regular hexagon; four hollow aluminum pipes are vertically arranged between the adjacent upper base and intermediate base and the intermediate base and lower base to support them, which can meet the requirements.

[0068] An obstacle crossing mechanism is installed at the contact position of the connecting support and the base structure; Figure 3As shown, the obstacle surmounting mechanism comprises a tripod 2, three obstacle surmounting wheels 1, two horizontal connecting rods 4, two vertical connecting rods 5 and a tensile spring 8, the two horizontal connecting rods are connected by the two vertical connecting rods to form a parallelogram structure, the parallelogram structure is deformable, and the connecting positions of the horizontal connecting rod and the vertical connecting rod are connected by an adapter connecting rod 6; two parallelogram structures are included, the planes of each parallelogram structure are perpendicular to the ground, and the two parallelogram structures are arranged in relative parallelism; a support shaft 3 is arranged at the center of the tripod, the tripod rotates on the support shaft, the parallelogram structure formed above has one end of the horizontal connecting rod extending outward, and the extension ends of the horizontal connecting rods of the two parallelogram structures are connected with the two ends of the support shaft respectively; the obstacle surmounting wheels are rotatably connected at the three vertices of the tripod, and a non-damping triangular wheel combined with a parallelogram is used here to achieve a 30cm cross-section obstacle surmounting; in the two parallelogram structures arranged in relative parallelism, a spring connecting plate 7 is arranged between the two horizontal connecting rods below, another spring connecting plate is arranged between the two vertical connecting rods away from the tripod, and a plurality of tensile springs are connected between the two spring connecting plates (in the preferred embodiment, two tensile springs can meet the requirements); Figure 1 As shown in the figure, the obstacle surmounting mechanism is installed in the upper connecting support, and each horizontal connecting rod below is fixed on the upper surface of the upper base through a wheel set support 13; the obstacle surmounting mechanism is installed in the lower connecting support, and each horizontal connecting rod above is fixed on the bottom surface of the lower base through a wheel set support. From

[0069] The two base structures are connected by a connecting support, and the connecting support is arranged in a horizontal manner, and the connecting support is arranged in a horizontal manner Figure 4 As shown, the annular driving guide rail mechanism is arranged between the two base structures, and the annular driving guide rail mechanism is arranged on the surface of the connecting support below, and the binocular camera detection device for detecting the bridge pier to be detected is arranged on the annular driving guide rail mechanism, and the annular driving guide rail mechanism is adapted to the size of the circumference of the bridge pier to be detected; Figure 5As shown, the annular driving track mechanism comprises a circular guide rail 18, a synchronous belt 19, a synchronous belt wheel 23, a guide wheel 20, a motor mounting seat 22 and a motor 27, the synchronous belt is arranged on the outer circumferential surface of the circular guide rail, the two circular surfaces of the circular guide rail are respectively matched with the wheel surfaces of the guide wheels, the two guide wheels are fixed on the guide wheel mounting seat 21, the guide wheel mounting seat is in a U-shaped form, and the two guide wheels are respectively arranged on the two vertical parts of the U-shaped guide wheel mounting seat; the surface of the synchronous belt is meshed with the synchronous belt wheel, the motor mounting seat is in an L-shaped form, the horizontal part of the L-shaped form is overlapped with the vertical part of the guide wheel mounting seat which is located above, the motor is installed on the motor mounting seat, and the motor shaft is connected with the synchronous belt wheel through a shaft coupling 26, that is, the motor drives the synchronous belt wheel to realize annular movement on the synchronous belt through the shaft coupling; it should be noted that, from Figure 6 As can be seen from the above, the guide wheel mounting seat and the motor mounting seat form a structure which almost covers the circular guide rail in the radial direction, two guide wheels and a synchronous belt wheel are arranged in the formed covering structure, the binocular camera detection device is installed on the motor mounting seat, and the motor is started, so that the binocular camera detection device can move in a ring shape under the drive of the synchronous belt wheel. Here, the guide wheels are combined with the synchronous belt wheel to guide the sliding of the binocular camera detection device, and the motor mounting seat can only move on the circular guide rail in a preset direction, so as to ensure the accuracy of the whole measurement. Finally, the circular guide rail is installed on the surface of the lower base through a guide rail support seat 24, and the bottom surface of the lower base is the obstacle crossing mechanism, so as to avoid interference between the obstacle crossing mechanism and the binocular camera detection device on the circular guide rail.

[0070] In the annular driving track mechanism, the circular guide rail is formed by splicing two semicircular guide rails, and the splicing positions of the two semicircular guide rails are fixed through a guide rail connecting plate 25, so that the size of the circumference of the circular guide rail can be adjusted in time to better adapt to the size of the circumference of the pier.

[0071] The so-called binocular camera detection device has multiple preferences, mainly including a structure formed by selecting two industrial cameras, Figure 4 As shown in the preferred embodiment provided in the present application, the binocular camera detection device comprises a cavity 29 and two industrial cameras 32, the opening of the cavity is closed by a cavity top plate 31 and a cavity bottom plate 28, and the sidewall of the cavity is provided with an opening, the two industrial cameras are fixed symmetrically in the cavity, and the camera lenses 33 of the industrial cameras are directed to the outside of the cavity through the opening, Figure 7 As shown in the arrangement diagram of the two industrial cameras, the sidewall of the cavity is made of transparent organic glass 35 so as not to affect the image taking of the industrial cameras. Figure 1 and Figure 2The structure of the submerging and rising mechanism can be clearly seen, which comprises a floating support plate, mounting profiles 38 and a plurality of propellers. The floating support plate 16 is connected below the lower base through a plurality of hollow aluminum pipes and is arranged in parallel with the lower base. A plurality of mounting profiles arranged in parallel are fixed on the surface of the floating support plate, and each mounting profile extends out of the floating support plate, and a propeller is mounted at each end of each mounting profile.

[0072] In the preferred embodiment, in the submerging and rising mechanism, two mounting profiles arranged in parallel are fixed on the surface of each floating plate support plate, and a propeller is mounted at each end of each mounting profile, that is, a total of eight propellers are included, and the eight propellers are symmetrically distributed, so that the rising and submerging of the entire platform can be stably completed.

[0073] The application also provides a detection method of the bridge underwater structure column-holding type obstacle-crossing detection platform. Figure 8 It can be seen that the method specifically comprises the following steps:

[0074] Step S1: calibrating the world coordinate system of a single industrial camera in a water-free environment;

[0075] Step S2: calibrating the world coordinate of the binocular industrial camera in the underwater environment;

[0076] Step S3: detecting that the platform is longitudinally submerged to a specified distance under water;

[0077] Step S4: collecting data of a plurality of measuring points at a specified position;

[0078] Step S5: performing point cloud calculation on the plurality of measuring points;

[0079] Step S6: performing rotation and translation matrix calculation on the plurality of measuring points;

[0080] Step S7: detecting that the platform rotates to complete point cloud splicing of each measuring point at the specified position;

[0081] Step S8: detecting that the platform continues to be longitudinally submerged to another specified distance under water, and repeating steps S4-S7 to complete point cloud calculation and splicing at each depth;

[0082] Step S9: splicing the point cloud data at the specified position at each underwater travel stage to complete the overall three-dimensional topographic measurement of the bridge pier to be detected.

[0083] The detection method is described in detail with the embodiment. First, the process of calibrating the world coordinate system of a single industrial camera in a water-free environment is as follows: Figure 9As shown, the concentric circular ring type code mark point is used to complete feature point extraction; each selected code mark point is relatively independent and unique, and each code point has a specific ID value, which is mainly used for pose estimation of each industrial camera shooting in measurement, i.e., determining the industrial camera external parameter. The code uses 15 code points, and the code band is equally divided into 15 parts, each part representing a binary bit, i.e., 0 or 1, and each circular ring can complete n binary numbers (corresponding to n decimal numbers). Since each code point needs to be identified and decoded, the code point size information is also the most critical information for code point identification and decoding. The code point is composed of 3 circular rings with diameter ratios of 5:12:20 Figure 8 The three circular rings with diameter ratios are formed by right side conversion.

[0084] Then, a single industrial camera is used to shoot a series of images of the surface of the component (the bridge pier to be detected) containing the code points, to complete the identification of the mark points and the positioning of the centers of the mark points. The specific process includes image preprocessing, edge extraction, feature identification and screening, and code point decoding. The image preprocessing mainly considers the image contrast and noise interference. For low-contrast images caused by insufficient illumination, the dynamic range of image processing gray level is improved through contrast stretching.

[0085] Then, a sub-pixel edge positioning circle center method based on Gaussian curve fitting is used. For the edge pixel sequence in the process of fitting into an ellipse, the sub-pixel positioning of the integer pixel edge is performed, and then the least square method is used to obtain the ellipse center. The sub-pixel positioning is completed by the Gaussian curve fitting method. In the case of known sub-pixel point coordinates, the gray value Ii(i=1, 2, 3...7) of the point is obtained by bilinear interpolation, and then the forward and backward difference is used to obtain 5 difference values. Finally, the 5 difference values are used to fit a one-dimensional Gaussian function to obtain the sub-pixel edge coordinate value. The least square method is used to realize high-precision ellipse fitting to obtain the ellipse center coordinate, and the three-dimensional coordinate reconstruction of each code point on the surface of the component is completed.

[0086] Finally, a self-calibration beam adjustment algorithm is used to optimize the reconstructed coordinates. The light beam formed by each surface point of the component and the camera is used as the basic adjustment unit, the pixel coordinates are used as the observation points, the error equation is determined by the collinearity equation, and the overall measurement area is unified for adjustment to optimize the camera internal and external parameters, and then the three-dimensional coordinate values in the space are reconstructed and optimized.

[0087] In order to calculate the point cloud three-dimensional space coordinates of each measuring point, the world coordinates of the underwater environment double industrial camera need to be calibrated in step S2. The chessboard calibration method is used, and the size of the chessboard is 11x8, and the size of the chessboard unit is 1mm. Figure 10 In a - hFor the whole detection platform after entering the water, the completed underwater calibration process can obtain the intrinsic and extrinsic parameters of the two industrial cameras (the rotation and translation matrix of the right industrial camera relative to the left industrial camera), wherein a-d are the left industrial camera calibration images, and e-h are the right industrial camera calibration images.

[0088] Steps S3-S7 are the process of detecting platform detecting each depth of underwater member, in order to avoid the detection platform turning in the same direction after diving in the wired transmission process and causing the mechanism to be locked by the wire, the detection platform collects data at each depth by Figure 11 The method shown in the figure is used to complete the image collection of each ring. Specifically, a motion block is arranged on the motion track, and after completing the image collection of each measuring point in the counterclockwise (or clockwise) direction from the block at the near-surface, it is submerged by 20 cm to the second stage, and the clockwise (counterclockwise) direction is completed. The second stage of image collection and continue to dive 20 cm, complete the counterclockwise (clockwise) direction collection, and so on. This method can avoid the interference of transmission line in the actual motion process of the detection platform, at the same time, it can accurately control the image collection of each ring measuring point at the specified position, reduce the cumulative distance error caused by motor driving, and help to improve the accuracy of the conversion of each measuring point point cloud coordinate system to the overall point cloud.

[0089] As Figures 12a-12b To realize the smooth conversion of multiple measuring points at any cross section underwater into a unified world coordinate system, 40 measuring points are designed in the ring through the distribution of coded points on the surface of the aboveground member. The camera motion position is accurately controlled by the motion base according to the target pulse number, the motor is driven to emit a motion distance of 700 pulses corresponding to each measuring point position, and the image information containing the coded points at this position is photographed. When the underwater detection platform is submerged to the specified depth, the specified position of the above-mentioned specified position is reached by driving the fixed pulse, and the point cloud data in the left camera coordinate system of the current measuring point can be converted into the coded point world coordinate system through the solved rotation and translation matrix. In this way, the underwater point cloud data of each measuring point can be unified into the world coordinate system.

[0090] The detection platform of the whole application adopts a steel structure, has high strength and long service life, and each connecting part is connected by bolts. The installation surface is also processed to ensure that the contact surface is flat after installation. The non-installation surface is sprayed with a common waterproof material on the market to meet the underwater use conditions and have a rust-proof function. Therefore, the bridge underwater structure column type obstacle detection platform and detection method provided by the application can detect the diseases of the bridge pier underwater, adapt to variable cross-section piers, and detect different heights and positions of the pier. The structure is stable, easy to install, and more stable and efficient in detection.

[0091] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0092] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0093] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0094] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A bridge underwater structure pillar-mounted obstacle-crossing detection platform, characterized in that: The rack body, the obstacle crossing mechanism, the binocular camera detection device, the annular driving track mechanism and the diving and ascending mechanism are included. The rack body includes two base structures arranged oppositely, two connecting supports (37) are connected between the two base structures, the two connecting supports (37) are arranged in parallel and are arranged in a stack, and there is a distance between adjacent connecting supports (37); each connecting support (37) is in the shape of a regular polygon, and the base structures are symmetrically mounted on the connecting support (37), that is, each base structure is connected to two connecting supports (37) on the same side at the same time. The obstacle crossing mechanism includes a plurality of, and each connecting support (37) is installed with an obstacle crossing mechanism at the contact position of the connecting support (37) and the base structure. The obstacle crossing mechanism includes a tripod (2), three obstacle wheels (1), a horizontal connecting rod (4), a vertical connecting rod (5), and a tension spring (8). Two horizontal connecting rods (4) are connected by two vertical connecting rods (5) to form a parallelogram structure, and the parallelogram structure is deformable, and the connecting position of the horizontal connecting rod (4) and the vertical connecting rod (5) is connected by a transfer connecting rod (6). It contains two parallelogram structures, the plane of each parallelogram structure is perpendicular to the ground, and the two parallelogram structures are arranged in parallel. The center of the tripod (2) is provided with a support shaft (3), and the tripod (2) rotates on the support shaft (3). The parallelogram structure formed above, one end of the horizontal connecting rod (4) of the upper parallelogram structure extends outward, and the extension ends of the two horizontal connecting rods (4) of the two parallelogram structures are connected with the two ends of the support shaft (3), respectively. The obstacle wheel (1) is rotatably connected at the three vertices of the tripod (2). In the two oppositely arranged parallelogram structures, a spring connecting plate (7) is arranged between the two lower horizontal connecting rods (4), another spring connecting plate (7) is arranged between the two vertical connecting rods away from the tripod (2), and a plurality of tension springs (8) are connected between the two spring connecting plates (7). An annular driving track mechanism is also arranged on the rack body, that is, an annular driving track mechanism is arranged between the two base structures, and the annular driving track mechanism is arranged on the surface of the lower connecting support (37). The binocular camera detection device for detecting the bridge pier to be detected is arranged on the annular driving track mechanism. The binocular camera detection device can move along the annular driving track mechanism. The annular driving track mechanism is combined with the obstacle crossing mechanism to adapt to the circumference of the bridge pier to be detected. A diving and ascending mechanism is installed at the bottom of each base structure to provide power for the diving and ascending of the detection platform.

2. The bridge underwater structure hugging columnar detectable obstacle crossing platform according to claim 1, characterized in that: The base structure includes an upper base (10), an intermediate base (9), and a lower base (11) arranged in a stack from top to bottom. The upper base (10), the intermediate base (9), and the lower base (11) are arranged in parallel with each other. In the vertical ground direction, the upper base (10) and the intermediate base (9), and the intermediate base (9) and the lower base (11) are supported by a plurality of hollow aluminum pipes (12).

3. The bridge underwater structure hugging columnar detectable obstacle crossing platform according to claim 2, characterized in that: In the obstacle crossing mechanism installed on the upper connecting support (37), each lower horizontal connecting rod (4) is fixed to the surface of the upper base (10) by a wheel set support (13). Each upper transverse connecting rod (4) is fixed to the bottom surface of the lower base (11) by a wheel group support (13) in the obstacle crossing mechanism installed in the lower connecting bracket (37).

4. The bridge underwater structure hugging columnar detectable obstacle crossing platform according to claim 3, characterized in that: The submersion and ascent mechanism comprises a floating support plate (16), a mounting profile (38), and a plurality of propellers (39), the floating support plate (16) is connected below the lower base (11) by a plurality of hollow aluminum pipes (12), and the floating support plate (16) is arranged parallel to the lower base (11); A plurality of parallel mounting profiles (38) are fixed on the surface of the floating support plate (16), each mounting profile (38) extends out of the floating support plate (16), and a propeller (39) is installed at each end of each mounting profile (38).

5. The bridge underwater structure hugging columnar detectable obstacle crossing platform according to claim 4, characterized in that: The annular driving track mechanism comprises a circular guide rail (18), a synchronous belt (19), a synchronous belt wheel (23), a guide wheel (20), a motor mounting seat (22), and a motor (27), the synchronous belt (19) is arranged on the outer circumferential surface of the circular guide rail (18), the two circular surfaces of the circular guide rail (18) parallel to the ground are respectively attached to the wheel surfaces of the guide wheels (20), the two guide wheels (20) are fixed on a guide wheel mounting seat (21), the guide wheel mounting seat (21) is in the shape of a U, and the two guide wheels (20) are respectively arranged on the two vertical parts of the U-shaped guide wheel mounting seat (21); the surface of the synchronous belt (19) is engaged with the synchronous belt wheel (23), the motor mounting seat (22) is in the shape of an L, the horizontal part of the L-shaped motor mounting seat (22) is overlapped with the upper vertical part of the guide wheel mounting seat (21), the motor (27) is installed on the motor mounting seat (22), and the shaft of the motor (27) is connected with the synchronous belt wheel (23) through a coupling (26), that is, the motor (27) drives the synchronous belt wheel (23) to move in a ring shape on the synchronous belt (19) through the coupling (26); The circular guide rail (18) is installed on the surface of the lower base (11) through a guide rail support seat (24); A binocular camera detection device is installed on the motor mounting seat (22).

6. The bridge underwater structure hugging columnar detectable obstacle crossing platform according to claim 5, characterized in that: The circular guide rail (18) is formed by splicing two semicircular guide rails (18), and the splicing part of the two semicircular guide rails (18) is fixed by a guide rail connecting plate (25).

7. The bridge substructure column-climbable obstacle-detector platform of claim 6, wherein: The connecting bracket (37) is in the shape of a regular hexagon; In the obstacle crossing mechanism, the tension spring (8) comprises two; In the submersion and ascent mechanism, two parallel mounting profiles (38) are fixed on the surface of each floating plate support plate, and a propeller (39) is installed at each end of each mounting profile (38).

8. A detection method based on the bridge underwater structure columnar obstacle-surmounting detection platform of claim 7, characterized in that: Specifically comprising the following steps: Step S1: calibrating the world coordinate system of a single industrial camera (32) in a water-free environment; Step S2: calibrating the world coordinate of the binocular industrial camera (32) in the underwater environment; Step S3: detecting the longitudinal submersion of the platform to a specified distance underwater; Step S4: collecting data of multiple measuring points at a specified position; Step S5: performing point cloud calculation on the multiple measuring points; Step S6: performing rotation and translation matrix calculation on the multiple measuring points; Step S7: detecting the rotation of the platform to complete the point cloud splicing of each measuring point in a ring. Step S8: the detection platform continues to dive longitudinally underwater to another specified distance, and steps S3-S7 are repeated, The point cloud calculation and splicing at each depth are completed; Step S9: the circumferential point cloud data of each underwater running stage are spliced to complete the overall three-dimensional topographic measurement of the bridge pier to be detected; In step S1, the method for calibrating the world coordinate system of the single industrial camera (32) in the water-free environment is as follows: firstly, the feature point extraction is performed on the concentric circular ring type coded mark points in the world coordinate system to be calibrated; a series of images of the surface of the bridge pier to be detected containing the coded points are shot by using the single industrial camera (32), the mark point recognition and the center positioning of the mark points are completed, the shot images are preprocessed, the edges are extracted, the features are recognized and screened, and the coded points are decoded; then, the three-dimensional coordinate reconstruction of each coded point on the surface of the bridge pier to be detected is completed, and the spatial three-dimensional coordinate values are optimized by using the self-calibration bundle adjustment algorithm.

9. The detection method of the bridge underwater structure column-holding type obstacle-surmounting detection platform according to claim 8, characterized in that: In step S2, the world coordinate of the binocular industrial camera in the underwater environment is calibrated by using the chessboard calibration method; In the repeated process of steps S3-S7, the detection platform repeats the circumferential image acquisition at the same descending distance in each stage, and the turning of the detection platform in adjacent stages is opposite.

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