Method and system for measuring relative relationship between underwater group piles during construction

Abstract

The present application belongs to underwater group pile construction measurement technical field, and relates to a kind of underwater group pile construction pile relative relationship measurement method and system.The method includes: measurement equipment installation step, scale is provided on the pile body of the first pile and the pile to be driven of the second pile, positioning point and vertically arranged multiple scale lines are provided on the scale, measurement platform is provided between the first pile position and the second pile position, and two cameras are coaxially installed on the measurement platform but set back;Pile relative relationship measurement step, two cameras shoot the scale on the first pile and the second pile to obtain scale image, calculate the horizontal distance between piles using the scale image on the first pile and the second pile and combining camera pose information, compare the scale image on the first pile and the second pile and calculate the elevation difference between piles combining camera pose information.The present application can realize the accurate measurement of underwater group pile construction pile relative relationship, and further realize the high-precision construction of underwater group pile.

Description

Technical Field

[0001] This invention belongs to the field of underwater pile group construction measurement technology, and relates to a method and system for measuring the relative relationship between piles in underwater pile group construction. Background Technology

[0002] Piling is a crucial component of marine engineering construction, including cross-sea bridges, offshore wind power foundations, and pile-foundation wharves. Piling is divided into two methods: single pile driving and pile group driving. Single pile driving primarily involves measuring the position and orientation of individual piles. Since piling vessels typically have only one hammer, pile group driving requires driving piles one by one to form a pile group. In addition to measuring the position and orientation of each individual pile in the group, it is even more important to accurately measure the relative relationships between the piles, i.e., the horizontal distance and elevation difference between multiple piles, to ensure that the relative relationships between the piles meet design requirements.

[0003] Currently, traditional piling typically involves piles that rise above the waterline. The process usually begins with positioning and attitude determination of the piling vessel using satellites and attitude sensors. Then, photoelectric sensors mounted on the piling vessel measure the horizontal distances and elevation differences between the vessel and the piles, as well as between multiple piles in a pile group. However, with the development of marine engineering into deep-sea areas, some projects require piling where the piles no longer rise above the waterline, thus introducing the technical requirement of underwater piling. In this case, the entire pile is underwater. For single-pile piling, the position and elevation of each pile can still be measured using the piling vessel's attitude and sensors mounted on the pile, although the accuracy will be reduced. For pile group piling, all measurements must be completed underwater. It is usually difficult to utilize surface information, such as auxiliary information from surface satellites. In other words, existing measuring instruments and methods cannot be applied underwater, making it extremely difficult to achieve high-precision measurements of the relative relationships between piles in an underwater pile group.

[0004] Measuring the relative relationships between piles in underwater pile group construction is a relatively new technical requirement, and there is currently no established and complete method. In some projects, multibeam scanning positioning methods or cable-stayed surveying methods have been attempted for measuring the relative relationships between piles in underwater pile group construction; however, both methods have the following shortcomings:

[0005] 1) When using multibeam scanning for measurement and positioning, the point spacing obtained by underwater multibeam measurement is related to the water depth. The greater the water depth, the larger the point spacing. Due to the large point spacing of multibeam measurement under deep water conditions, it is impossible to accurately obtain the shape of the pile, resulting in a large error in the calculation of the pile center point position. It is impossible to accurately determine the height difference of the pile top, resulting in low measurement accuracy and difficulty in meeting the needs of high-precision construction.

[0006] 2) When using cable measurement for positioning, the pile position is calculated by measuring the length of the vibratory hammer cable. The accuracy requirements for the measurement of cable length and cable direction are high. However, under the influence of ocean currents on the lateral thrust of the cable and ship motion, the straight distance from the cable suspension point to the vibratory hammer and the actual attitude of the cable will produce large measurement errors. As the depth of the vibratory hammer in the water increases, the measurement error also increases, which cannot meet the accuracy requirements for pile positioning in deep water.

[0007] In view of this, how to accurately measure the relative relationship between piles in underwater pile group construction has become a technical problem that urgently needs to be solved in the industry. Summary of the Invention

[0008] To address the shortcomings of related technologies, this invention provides a method and system for measuring the relative relationship between piles in underwater pile group construction, aiming to achieve accurate measurement of the relative relationship between piles in underwater pile group construction, thereby realizing high-precision construction of underwater pile groups.

[0009] This invention provides a method for measuring the relative relationship between piles in underwater pile group construction, comprising the following steps:

[0010] S1. Installation steps for measuring equipment, including:

[0011] S11. Setting of scale: A scale is set on the pile body of the first pile that has been driven and the pile body of the second pile to be driven. The scale extends downward from the top of the pile body. The scale has a positioning point and multiple scale lines set vertically at intervals below the positioning point.

[0012] S12. Setting up the underwater camera group: A measurement platform is set up between the pile position of the first pile that has been driven and the pile position of the second pile to be driven. An underwater camera group is installed on the measurement platform. The underwater camera group includes a first camera and a second camera that are coaxial but set opposite to each other. An attitude sensor is installed on the underwater camera group.

[0013] S2. The measurement procedure for the relative relationship between piles, which is carried out during the underwater pile driving process of the second pile, includes:

[0014] S21. Marker identification: The first camera and the second camera simultaneously take pictures of the markers on the first stake and the second stake respectively to obtain images of the markers on the first stake and the second stake.

[0015] S22. Calculation of horizontal distance between piles: Calculate the distance between the first camera and the first pile using the scale image obtained by the first camera. The distance between the second camera and the second stake is calculated using the scale image obtained by the second camera. By combining the attitude information of the underwater camera array, the horizontal distance between the second and first piles is calculated. ;

[0016] S23. Calculation of elevation difference between piles: Compare the scale images obtained by the first camera and the second camera, and calculate the scale difference between the corresponding position of the second camera axis on the second pile and the corresponding position of the first camera axis on the first pile. Based on the attitude information from the underwater camera array, the elevation difference between the second and first piles is calculated. .

[0017] In some embodiments, in step S11, the positioning points on the scale are marked using multiple concentric black and white circles, arranged from the inside out. The radius of each circle is , The radius of the smallest circle; the vertical distance from the first scale line below the positioning point to the center of the circle at the positioning point is... The distance between two adjacent scale lines is The distance between the left and right ends of each scale line is Each scale line is formed by two short scale lines that are collinear but not connected on the left and right, or by one long scale line and one short scale line that are collinear but not connected on the left and right.

[0018] In some embodiments, step S21 includes the following steps:

[0019] S211. Identification of the center and radius of the positioning point: The Canny edge detection operator is used to obtain a binary edge map from the scale images obtained by the first and second cameras. ,right The candidate circle set is obtained by applying the Hough circle transform. Candidate circles are sorted by their center coordinates. Clustering: Circles within the same cluster are considered concentric circles; circles within concentric circles are then classified by radius. Sort in ascending order and fit using the RANSAC algorithm to obtain the result that meets the requirements. , … The concentric circles whose radius varies according to the law; the image coordinates of the center of the positioning point are obtained by fitting according to equation (1). The radius of the smallest circle in the concentric circles is obtained by fitting the least squares method according to equation (2). ;

[0020] (1);

[0021] (2);

[0022] S212. Generation of the theoretical centerline of the scale line: Establish a measurement coordinate system with the center of the positioning point as the origin, then the line below the positioning point... The theoretical coordinates of the left endpoint of the scale line are: The coordinates of the right endpoint are The line connecting the left and right endpoints of each scale line is the theoretical center line of that scale line; among them, This is the theoretical length of the scale line on the ruler image. ; This represents the theoretical vertical distance from the center of the circle at the first scale line below the positioning point on the scale image. ; This represents the theoretical distance between two adjacent scale lines on the scale image. ; The ratio of the orthogonal projection of the first or second camera. ;

[0023] S213, Retrieval and Measurement of Actual Scale Line Position: Based on the... Using the left and right endpoints of the line in the scale line theory as a reference, a rectangular search area is constructed. , expressed as equation (3), where, To allow for observation error tolerance; in The horizontal scan within the region is performed, and the vertical mean is calculated according to equation (4). ,in, The image is grayscale; according to equation (5), the gradient extrema are fitted using a quadratic function. ; Calculate and output the first according to equation (6) The scale value of the scale line ;

[0024] (3);

[0025] (4);

[0026] (5);

[0027] (6).

[0028] In some embodiments, step S21 further includes S214, scale code redundancy detection;

[0029] First, the validity of the encoded scale is detected using a masking method. Specifically, the code for each scale line, where the left side is a long scale line and the right side is a short scale line, is set to... The code for each scale line, with a short scale line on the left and a long scale line on the right, is set as follows: The code for each scale line, which has short scale lines on both the left and right sides, is set as follows: Each code is [length] Each graduation line that passes the validity test of the coding scale is considered a valid graduation line and meets the imaging quality verification conditions. Use the least squares method or linear regression method to fit all valid scale lines. Observed values;

[0030] Then, it is determined whether the scale code redundancy detection meets the convergence condition. The convergence condition is that the proportion of effective scale lines is greater than threshold A and the error of the observed value after fitting the effective scale lines is less than threshold B. If the convergence condition is met, the scale values ​​of all effective scale lines are output, and the verified scale image is obtained. If the convergence condition is not met, the left and right ends of the top effective scale line and the left and right ends of the bottom effective scale line are found, and the image coordinates of the center of the positioning point are calculated using affine transformation. The smallest circle radius concentric with the positioning point The theoretical value is used as the input for step S212. Steps S212 to S214 are executed again. Iterative detection is performed in this way until the convergence condition is met, and the verified scale image is obtained.

[0031] In some embodiments, step S22 includes calculating the horizontal distance between the second pile and the first pile according to equation (7). ;in, This is the correction value for the distance between the first camera and the first stake. This is the correction value for the distance between the second camera and the second stake. The tilt angle value of the second camera as measured by the attitude sensor;

[0032] (7).

[0033] In some embodiments, step S23 includes calculating the elevation difference between the second pile and the first pile according to equation (8). ;in, This represents the vertical offset of the first camera's axial position. This represents the vertical offset of the second camera's axial position. The tilt angle value of the second camera as measured by the attitude sensor;

[0034] (8).

[0035] In some embodiments, in step S12, the measuring platform is an underwater robot; in step S21, the underwater robot drives the underwater camera group to move so that the scales on the first and second piles enter the field of view of the first and second cameras, respectively.

[0036] In some embodiments, in step S12, a gimbal is installed at the bottom of the underwater camera group and mounted on the measurement platform; in step S21, the gimbal drives the underwater camera group to rotate so that the first camera and the second camera are respectively facing the scales on the first stake and the second stake.

[0037] In some embodiments, in step S11, the ruler is pasted or painted on the pile body; there are multiple rulers, and the multiple rulers are arranged at intervals along the circumference of the pile body.

[0038] This invention also provides a system for measuring the relative relationship between piles in underwater pile group construction, applicable to the aforementioned method for measuring the relative relationship between piles in underwater pile group construction. The system for measuring the relative relationship between piles in underwater pile group construction includes:

[0039] Multiple scales are set on the pile body of the first pile that has been driven and the pile body of the second pile to be driven; the scales extend downward from the top of the pile body and have positioning points and multiple scale lines set vertically at intervals below the positioning points.

[0040] The measurement platform is located between the location of the first pile that has already been driven and the location of the second pile to be driven; the measurement platform is an underwater robot.

[0041] An underwater camera assembly is mounted on a measurement platform via a gimbal. The underwater camera assembly includes a first camera and a second camera arranged coaxially but facing away from each other. The first camera and the second camera are used to acquire images of the scales on the first and second stakes, respectively. The gimbal is used to rotate the underwater camera assembly so that the first camera and the second camera are facing the scales on the first and second stakes, respectively. An attitude sensor is installed on the underwater camera assembly to acquire the attitude information of the underwater camera assembly in real time. An auxiliary light source is provided on the underwater camera assembly or the measurement platform.

[0042] The processor is connected to the underwater camera group; the processor has a built-in computing unit and a control unit; the computing unit performs image enhancement and scale recognition on the scale images acquired by the first and second cameras, and calculates the horizontal distance and elevation difference between the second pile to be driven and the first pile that has been driven, in combination with the attitude information of the underwater camera group; the control unit is used to control the rotation of the gimbal, control the start and stop of the shooting and measurement of the first and second cameras, and adjust the illumination of the auxiliary light source;

[0043] The floating work platform is deployed above the water surface; it is connected to the computing unit to obtain the calculation results of the computing unit in real time; it is connected to the control unit to monitor the operation of the control unit; and it is connected to the underwater robot to remotely control the movement of the underwater robot.

[0044] Based on the above technical solution, the underwater pile group construction pile relative relationship measurement method and system in the embodiments of the present invention solves the problem of difficulty in accurately measuring the pile relative relationship during underwater pile group construction by combining underwater camera measurement technology and scale on the pile body. It can realize accurate measurement of the pile relative relationship during underwater pile group construction, thereby realizing high-precision construction of underwater pile groups. Attached Figure Description

[0045] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0046] Figure 1 This is a flowchart of the underwater pile group construction method for measuring the relative relationship between piles according to the present invention.

[0047] Figure 2 This is a schematic diagram of the underwater pile group construction pile relative relationship measurement system of the present invention;

[0048] Figure 3 This is a schematic diagram of the scale in the underwater pile group construction pile relative relationship measurement system of the present invention;

[0049] Figure 4 This is a flowchart of the scale identification step in the underwater pile group construction relative relationship measurement method of the present invention. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "top", "bottom", "inner", "outer", "left", "right", "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] refer to Figures 1-4 As shown, the present invention provides a method for measuring the relative relationship between piles in underwater pile group construction. This method is used to measure the relative relationship (i.e., the horizontal distance and elevation difference between the two piles) between a single pile being driven and the first pile (or other piles already driven) during the subsequent driving of other piles after the first pile in the pile group has been driven.

[0055] The method for measuring the relative relationship between piles in underwater pile group construction includes the following steps:

[0056] S1. Measuring equipment installation steps, which include:

[0057] S11. Setting of the scale: A scale is set on the pile body of the first pile that has been driven and the pile body of the second pile to be driven. The scale extends downward from the top of the pile body. The scale has positioning points and multiple scale lines. The scale lines are located below the positioning points and are evenly spaced vertically. Specifically, the height of the positioning point on the scale from the top surface of the pile body is known. The starting point of the scale is determined by setting the positioning point, and the scale is made measurable by setting multiple scale lines.

[0058] S12. Setting up the underwater camera group: A measuring platform is set up between the pile position of the first pile that has been driven and the pile position of the second pile to be driven. An underwater camera group is installed on the measuring platform. The underwater camera group includes a first camera and a second camera that are coaxial but opposite to each other. That is, the axes of the first camera and the second camera are collinear but installed in opposite directions at 180°. Both the first camera and the second camera are high-resolution industrial cameras. Furthermore, the specific layout of the underwater camera group must ensure that the scales on the first pile and the second pile can be located within the field of view of the first camera and the second camera, respectively. An attitude sensor is installed on the underwater camera group. The attitude sensor can be used to obtain the attitude information of the underwater camera group, such as the pitch angle of the first camera and the second camera.

[0059] S2. Measurement steps for the relative relationship between piles: This step is carried out during the underwater pile driving process of the second pile. This step includes:

[0060] S21. Marker identification: The first camera and the second camera simultaneously take pictures of the marks on the first stake and the second stake respectively to obtain the marks on the first stake and the second stake. Based on this, the positioning point on each mark and several scale lines below the positioning point can be identified.

[0061] S22. Calculation of horizontal distance between piles: Calculate the distance between the first camera and the first pile using the scale image obtained by the first camera. The distance between the second camera and the second stake is calculated using the scale image obtained by the second camera. By combining the attitude information of the underwater camera array, the horizontal distance between the second and first piles is calculated. It should be noted that the ratio between the viewing distance and the pixel size of the two cameras was calibrated before use. The distance between the camera and the pile can be calculated based on the scale image. The calculation method is well known to those skilled in the art and will not be elaborated here.

[0062] S23. Calculation of elevation difference between piles: Compare the scale images obtained by the first camera and the second camera, and calculate the scale difference between the corresponding position of the second camera axis on the second pile and the corresponding position of the first camera axis on the first pile. Based on the attitude information from the underwater camera array, the elevation difference between the second and first piles is calculated. .

[0063] The above illustrative embodiment, through the setting of a measurement platform between two piles and two cameras on it, and the setting of scales on the two piles, can simultaneously acquire scale images on the two piles using two cameras. By combining these images with the real-time attitude information of the cameras, the horizontal distance and elevation difference between the two piles can be calculated, and the measurement results of the relative relationship between the piles can be obtained, thereby realizing the relative positioning during underwater pile driving. Therefore, by combining underwater camera measurement technology and scales on the piles, the problem of accurately measuring the relative relationship between piles during underwater pile construction is solved, thereby achieving high-precision construction of underwater piles.

[0064] refer to Figure 3 As shown, in some embodiments, in step S11, the positioning points on the scale are marked using multiple concentric black and white circles, arranged from the inside out. The radius of each circle is , This is the radius of the smallest circle among the concentric circles. The vertical distance from the first scale line below the positioning point to the center of the circle at the positioning point is... The distance between two adjacent scale lines is The distance between the left and right ends of each scale line is The distance between the left and right ends of all scale lines is equal. Each scale line is formed by two short scale lines that are collinear but not connected left and right, or by one long scale line and one short scale line that are collinear but not connected left and right. Furthermore, all scale lines form two sub-scales located on the left and right sides of the main scale. Each sub-scale includes multiple long scale lines and multiple short scale lines located between two adjacent long scale lines, and the long scale lines in the two sub-scales are staggered. Specifically, five short scale lines can be set between two adjacent long scale lines, but this is not limited to this. The length of the long scale line can be twice the length of the short scale line, and the length of the long scale line can be set to... The end of the longer scale line facing the shorter scale line can be pointed for easier identification. This illustrative embodiment refines the specific design of the positioning points and scale lines on the ruler, facilitating subsequent identification of the ruler in images captured by a camera.

[0065] refer to Figures 1-4 As shown, in some embodiments, step S21 includes the following steps:

[0066] S211. Identification of the center and radius of the positioning point: The Canny edge detection operator is used to obtain a binary edge map from the scale images obtained by the first and second cameras. ,right Applying the Hough Circle Transform, we obtain the set of candidate circles. Candidate circles are sorted by their center coordinates. Clustering treats circles within the same cluster as concentric circles, thus eliminating interfering circle information from the candidate circle set; circles within the concentric clusters are then sorted by radius. Sort in ascending order, and fit the results using the RANSAC (Random Sample Consensus) algorithm to obtain a result that conforms to the desired outcome. , … The concentric circles whose radius varies are identified as positioning points on the scale; the image coordinates of the center of the positioning point are obtained by fitting according to equation (1). The radius of the smallest circle in the concentric circles is obtained by fitting the least squares method according to equation (2). ;

[0067] (1);

[0068] (2).

[0069] S212. Generation of the theoretical centerline of the scale line: Establish a measurement coordinate system with the center of the positioning point as the origin, then the line below the positioning point... The theoretical coordinates of the left endpoint of the scale line are: The coordinates of the right endpoint are The line connecting the left and right endpoints of each scale line is the theoretical center line of that scale line; among them, This is the theoretical length of the scale line on the ruler image. ; This represents the theoretical vertical distance from the center of the circle at the first scale line below the positioning point on the scale image. ; This represents the theoretical distance between two adjacent scale lines on the scale image. ; This represents the ratio of the orthogonal projection of the first or second camera, i.e., the proportional relationship between the object space and the image space. .

[0070] S213, Retrieval and Measurement of Actual Scale Line Position: Based on the... Using the left and right endpoints of the line in the scale line theory as a reference, a rectangular search area is constructed. , expressed as equation (3), where, To allow for observation error tolerance; in The horizontal scan within the region is performed, and the vertical mean is calculated according to equation (4). ,in, The image is grayscale; according to equation (5), the gradient extrema are fitted using a quadratic function. ; Calculate and output the first according to equation (6) The scale value of the scale line ;

[0071] (3);

[0072] (4);

[0073] (5);

[0074] (6).

[0075] The above illustrative embodiment enables preliminary identification of the ruler in a ruler image captured by a camera.

[0076] refer to Figures 1-4 As shown, in some embodiments, step S21 further includes S214, scale code redundancy detection.

[0077] First, the validity of the encoded scale is detected using a masking method. Specifically, the code for each scale line, where the left side is a long scale line and the right side is a short scale line, is set to... The code for each scale line, with a short scale line on the left and a long scale line on the right, is set as follows: The code for each scale line, which has short scale lines on both the left and right sides, is set as follows: Each code is [length] Referring to the theoretical design layout of the long and short scale lines on the scale, each scale line is subjected to a coding scale validity test. Each scale line that passes the coding scale validity test is considered a valid scale line and is denoted as a valid scale line. By detecting the validity of the coded scale, invalid scale lines that are obscured or missing by underwater foreign objects are removed; the least squares method or linear regression method is used to fit all valid scale lines. The observed values.

[0078] Then, it is determined whether the redundancy detection of the scale code meets the convergence condition. The convergence condition is that the proportion of effective scale lines is greater than threshold A (e.g., 80%) and the error of the observed value after fitting the effective scale lines is less than threshold B (e.g., equivalent to 1mm). If the convergence condition is met, the scale values ​​of all effective scale lines are output, and the complete scale lines are restored accordingly to obtain the verified scale image. If the convergence condition is not met, the left and right ends of the top effective scale line and the left and right ends of the bottom effective scale line are found, and the image coordinates of the center of the positioning point are calculated using affine transformation. The smallest circle radius concentric with the positioning point The theoretical value is used as the input for step S212. Steps S212 to S214 are executed again. Iterative detection is performed in this way until the convergence condition is met, and the verified scale image is obtained.

[0079] The above illustrative embodiment enables rapid detection of the validity of the scale lines underwater by encoding the scale lines. Even if individual scale lines are obscured or lost, it will not affect the overall identification of the scale, thereby achieving accurate identification of the scale in the scale image captured by the camera.

[0080] refer to Figure 1 , Figure 2 As shown, in some embodiments, step S22 includes calculating the horizontal distance between the second pile and the first pile according to equation (7). ;in, This is the correction value for the distance between the first camera and the first stake. This is the correction value for the distance between the second camera and the second stake. The tilt angle value of the second camera as measured by the attitude sensor;

[0081] (7).

[0082] Further explanation of the correction value for the distance between the first camera and the first stake. The calculation principle is shown in equations (71)-(73). The calculation is similar; where, This represents the ratio between the view distance and pixel size of the first camera. The pixel dimensions in the scale image obtained by the first camera. for The value after tilt correction;

[0083] (71);

[0084] (72);

[0085] (73)

[0086] The above illustrative embodiments refine the calculation method for the horizontal distance between piles. Considering the influence of the actual camera posture on the distance measurement results, the horizontal distance between piles in underwater pile group construction can be obtained more accurately by longitudinally correcting the distance measured by the camera.

[0087] refer to Figure 1 , Figure 2 As shown, in some embodiments, step S23 includes calculating the elevation difference between the second pile and the first pile according to equation (8). ;in, This represents the vertical offset of the first camera's axial position. This represents the vertical offset of the second camera's axial position. The tilt angle value of the second camera as measured by the attitude sensor;

[0088] (8).

[0089] It should be noted that the vertical offset of the first camera's axis position... Theoretically equal to When mounting the underwater camera assembly onto the measurement platform, theoretically, the axes of the first and second cameras should be horizontal. However, it is actually very difficult to make the camera axis perfectly horizontal. It can be considered as a small angle value, and When it is relatively small, it can be considered in the industry ,thus, ; The calculation is similar.

[0090] The above illustrative embodiments refine the calculation method for the elevation difference between piles. Considering the influence of the actual camera posture on the measurement results, by correcting the position of the camera axis, the elevation difference between piles in underwater pile group construction can be obtained more accurately.

[0091] refer to Figure 2 As shown, in some embodiments, in step S12, the measuring platform is an underwater robot. In step S21, the underwater robot can move the underwater camera group to a suitable position so that the scales on the first and second piles enter the field of view of the first and second cameras, respectively; it is understood that the field of view of the cameras should include the positioning point and multiple scale lines below the positioning point (but not necessarily all scale lines). This illustrative embodiment uses an underwater robot as the measuring platform, realizing the flexible deployment and mobility of the measuring platform, which facilitates the measurement of the relative relationships between different piles during pile group construction.

[0092] refer to Figure 1 , Figure 2 As shown, in some embodiments, in step S12, a gimbal is installed at the bottom of the underwater camera group and mounted on the measurement platform; in step S21, the gimbal can drive the underwater camera group to rotate so that the first camera and the second camera can be directly facing the scales on the first and second stakes, respectively, to facilitate the shooting of scale images.

[0093] refer to Figure 2 , Figure 3 As shown, in some embodiments, in step S11, the ruler is pasted or painted on the pile body, or detachably installed on the pile body. There can be multiple rulers, that is, multiple rulers can be set on a pile body, and the multiple rulers are arranged at intervals along the circumference of the pile body; the number and distribution of the rulers on the pile body can be flexibly set according to the measurement needs.

[0094] refer to Figure 2 , Figure 3 As shown, the present invention also provides a system for measuring the relative relationships between piles in underwater pile group construction, applicable to the aforementioned method for measuring the relative relationships between piles in underwater pile group construction. The system includes a scale, a measuring platform, an underwater camera group, a processor, and a surface workbench.

[0095] Multiple scales are installed on the pile body of the first pile that has already been driven and on the pile body of the second pile to be driven. The scales extend downwards from the top of the pile body and have positioning points and multiple scale lines. The scale lines are located below the positioning points and are evenly spaced vertically. Specifically, the positioning points on the scales are marked by black and white concentric circles formed by multiple circles. Each scale line below the positioning point is formed by two short scale lines that are collinear but not connected horizontally, or by one long scale line and one short scale line that are collinear but not connected horizontally. Each scale line can be coded to meet the needs of underwater scale line identification and detection. The size and spacing of the concentric circles, and the length and spacing of the long and short scale lines can be specifically set with reference to water depth, water quality environment, pile distance, measurement accuracy requirements, etc., to avoid problems such as underwater long-distance imaging blurring or fusion.

[0096] The measurement platform is positioned between the location of the first driven pile and the location of the second pile to be driven. The measurement platform can be a fixed underwater platform or an underwater robot; using an underwater robot as the measurement platform allows for flexible deployment and mobility.

[0097] The underwater camera assembly is mounted on the measurement platform via a gimbal. The assembly includes a first camera and a second camera, coaxial but opposite to each other; that is, the axes of the first and second cameras are collinear but mounted at a 180° angle. Both cameras are high-resolution industrial cameras, used to acquire images of the scales on the first and second piles, respectively. It should be noted that the axes of the first and second cameras can also be set to a non-180° angle, coplanar but not collinear. However, when measuring the relative relationship between underwater piles, the installation angle must be calibrated beforehand, and relevant conversions must be performed in subsequent calculations. The gimbal is used to rotate the underwater camera assembly so that the first and second cameras are directly facing the scales on the first and second piles, respectively.

[0098] The underwater camera assembly is equipped with attitude sensors to acquire its attitude information in real time, such as the pitch angles of the first and second cameras. It should be noted that attitude sensors may not be installed on the underwater camera assembly; instead, the underwater camera assembly can be mounted on an underwater robot, and their spatial orientation relationship can be calibrated, allowing the attitude information of the underwater robot to be obtained.

[0099] Auxiliary light sources can be set up on underwater camera groups or measurement platforms. When the camera is taking pictures of the scale, if the ambient light is insufficient, the auxiliary light source can be used to provide illumination, enabling the camera to obtain a clear image of the scale, which is beneficial to improving the accuracy of underwater video measurement.

[0100] The processor is connected to the underwater camera group; it incorporates a computing unit and a control unit. The computing unit performs image enhancement and scale recognition on the scale images acquired by the first and second cameras, combining the scale image data with the attitude information of the underwater camera group to calculate the horizontal distance and elevation difference between the second pile to be driven and the first pile already driven. The control unit controls the rotation of the pan-tilt unit, adjusting the rotation angle based on the scale images seen by the cameras to regulate the relationship between the cameras and the scale, enabling the cameras to automatically align with the scale. The control unit also controls the start and stop of shooting measurements by the first and second cameras, and regulates the illumination of auxiliary light sources, etc.

[0101] The floating work platform is deployed above the water surface and can be a computer or other equipment with functions such as storage, memory, logical judgment, information processing, and communication control. The platform can be located on a construction vessel or other surface platform. The platform communicates with the computing unit to obtain its calculation results in real time; it also communicates with the control unit to monitor its operation; and it communicates with the underwater robot to remotely control its movement.

[0102] To further explain, during the underwater pile driving process of the second pile, when measuring the relative relationship between piles, the surface work platform directs the underwater robot to move the underwater camera group to a suitable position between the piles. The gimbal rotates so that the first and second cameras are directly facing the scales on the first and second piles, respectively. The surface work platform issues a measurement command, and the two cameras simultaneously acquire images of the scales on the two piles. The calculation unit calculates the horizontal distance and elevation difference between the piles based on the scale image data and camera attitude information, thereby obtaining the measurement results of the relative relationship between the piles, and transmitting the results to the surface work platform. Those skilled in the art will understand that if the relative relationship between the piles is found to be inconsistent with the design requirements during the underwater pile driving process of the second pile, the pile driving position of the second pile should be adjusted or the elevation of the second pile should be controlled in a timely manner according to the measurement results to achieve high-precision construction of the underwater pile group.

[0103] Through the description of several embodiments of the underwater pile group construction pile relative relationship measurement method and system of the present invention, it can be seen that the present invention has at least one or more of the following advantages:

[0104] 1) This invention, by setting up a measuring platform and a first and second camera coaxially but oppositely positioned on it between two piles that have been driven and those to be driven, and by setting scales on the two piles, can simultaneously acquire images of the scales on the two piles using the two cameras. By combining these images with the real-time attitude information of the cameras, the horizontal distance and elevation difference between the two piles can be accurately calculated, and the measurement results of the relative relationship between the piles can be obtained. It has been verified that the measurement accuracy can reach the centimeter level, which is higher than other existing underwater measurement methods. Therefore, by combining underwater video measurement technology and scales on the piles, the problem of accurately measuring the relative relationship between piles during underwater pile group construction is solved, thereby achieving high-precision construction of underwater pile groups.

[0105] 2) This invention enables rapid underwater detection of the validity of scale lines by encoding the scale lines on the scale, and restores the complete scale lines based on the detected valid scale lines, thereby achieving accurate identification of the scale and improving measurement accuracy.

[0106] 3) This invention uses an underwater robot as a measurement platform and a gimbal to mount the underwater camera group on the measurement platform, which makes it easy to quickly adjust the two cameras to be directly facing the scales on the two piles, thus meeting the measurement needs of the relative relationship between different piles and improving measurement efficiency.

[0107] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for measuring the relative relationship between piles in underwater pile group construction, characterized in that, Includes the following steps: S1. Installation steps for measuring equipment, including: S11. Setting of scale: A scale is set on the pile body of the first pile that has been driven and the pile body of the second pile to be driven. The scale extends downward from the top of the pile body. The scale is provided with positioning points and multiple scale lines that are located below the positioning points and are vertically spaced. S12. Setting up the underwater camera group: A measuring platform is set up between the pile position of the first pile that has been driven and the pile position of the second pile to be driven. An underwater camera group is installed on the measuring platform. The underwater camera group includes a first camera and a second camera that are coaxial but opposite to each other. An attitude sensor is installed on the underwater camera group. S2, the measurement procedure for the relative relationship between piles, which is carried out during the underwater pile driving process of the second pile, includes: S21. Marker identification: The first camera and the second camera simultaneously take pictures of the markers on the first stake and the second stake respectively to obtain images of the markers on the first stake and the second stake. S22. Calculation of horizontal distance between piles: Calculate the distance between the first camera and the first pile using the scale image obtained by the first camera. The distance between the second camera and the second stake is calculated using the scale image obtained by the second camera. Based on the attitude information of the underwater camera group, the horizontal distance between the second pile and the first pile is calculated. ; S23. Calculation of elevation difference between piles: Compare the scale images obtained by the first camera and the second camera, and calculate the scale difference between the corresponding position of the second camera axis on the second pile and the corresponding position of the first camera axis on the first pile. Based on the attitude information of the underwater camera group, the elevation difference between the second pile and the first pile is calculated. .

2. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 1, characterized in that, In step S11, the positioning points on the scale are marked using multiple concentric black and white circles, arranged from the inside out. The radius of each of the circles is , The minimum radius of the circle; the vertical distance from the first scale line below the positioning point to the center of the circle is... The spacing between two adjacent scale lines is The distance between the left and right ends of each of the aforementioned scale lines is Each scale line is formed by two short scale lines that are collinear but not connected on the left and right, or by one long scale line and one short scale line that are collinear but not connected on the left and right.

3. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 2, characterized in that, Step S21 includes the following steps: S211. Identification of the center and radius of the positioning point: The Canny edge detection operator is used to obtain a binary edge map from the scale images obtained by the first and second cameras. ,right The candidate circle set is obtained by applying the Hough circle transform. The candidate circles are arranged according to their center coordinates. Clustering is performed where circles within the same cluster are considered concentric circles; circles within the concentric circles are then classified by radius. Sort in ascending order and fit using the RANSAC algorithm to obtain the result that meets the requirements. , … The concentric circles whose radius varies according to the law; the image coordinates of the center of the positioning point are obtained by fitting according to equation (1). The radius of the smallest circle among the concentric circles is obtained by fitting the data using the least squares method according to equation (2). ; (1)； (2)； S212, Generation of the theoretical center line of the scale line: Establish a measurement coordinate system with the center of the positioning point as the origin, then the line below the positioning point... The theoretical coordinates of the left endpoint of the scale line are: The coordinates of the right endpoint are The line connecting the left and right endpoints of each scale line is the theoretical center line of that scale line; where, This is the theoretical length of the scale line on the ruler image. ; The theoretical vertical distance from the center of the circle at the first scale line below the positioning point on the scale image. ; This represents the theoretical distance between two adjacent scale lines on the ruler image. ; The ratio of the orthogonal projection of the first or second camera. ; S213, Retrieval and Measurement of Actual Scale Line Position: Based on the... Based on the left and right endpoints of the scale line in the above-described theory, a rectangular search area is constructed. , expressed as equation (3), where, To allow for observation error tolerance; in The horizontal scan within the region is performed, and the vertical mean is calculated according to equation (4). ,in, The image is grayscale; according to equation (5), the gradient extrema are fitted using a quadratic function. ; Calculate and output the first according to equation (6) The scale value of the scale line mentioned above ; (3)； (4)； (5)； (6)。 4. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 3, characterized in that, Step S21 also includes S214, scale code redundancy detection; First, the validity of the encoded scale is detected using a masking method. Specifically, the code for each scale line, where the left side is a long scale line and the right side is a short scale line, is set as follows: The code for each scale line, with a short scale line on the left and a long scale line on the right, is set as follows: The code for each scale line, which has short scale lines on both the left and right sides, is set as follows: Each code is [length] Each scale line that passes the validity test of the encoded scale is considered a valid scale line and is denoted as a valid scale line. The least squares method or linear regression method is used to fit all the effective scale lines. Observed values; Then, it is determined whether the scale code redundancy detection meets the convergence condition; the convergence condition is that the proportion of effective scale lines is greater than threshold A and the error of the observed value after fitting the effective scale lines is less than threshold B; if the convergence condition is met, the scale values ​​of all effective scale lines are output, thereby obtaining the verified scale image; if the convergence condition is not met, the left and right ends of the uppermost effective scale line and the left and right ends of the lowermost effective scale line are found, and the image coordinates of the center of the positioning point are calculated using affine transformation. The smallest circle radius concentric with the positioning point The theoretical value is used as the input for step S212. Steps S212 to S214 are executed again. Iterative detection is performed in this way until the convergence condition is met, and the verified scale image is obtained.

5. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 4, characterized in that, Step S22 includes calculating the horizontal distance between the second pile and the first pile according to equation (7). ;in, This is the correction value for the distance between the first camera and the first stake. This is the correction value for the distance between the second camera and the second stake. The tilt angle value of the second camera measured by the attitude sensor; (7)。 6. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 4, characterized in that, Step S23 includes calculating the elevation difference between the second pile and the first pile according to equation (8). ;in, This represents the vertical offset of the first camera's axial position. This represents the vertical offset of the second camera's axial position. The tilt angle value of the second camera measured by the attitude sensor; (8)。 7. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 1 or 2, characterized in that, In step S12, the measuring platform is an underwater robot; in step S21, the underwater robot drives the underwater camera group to move so that the scales on the first and second piles enter the field of view of the first and second cameras, respectively.

8. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 7, characterized in that, In step S12, a gimbal is installed at the bottom of the underwater camera group and mounted on the measurement platform; in step S21, the gimbal drives the underwater camera group to rotate so that the first camera and the second camera are respectively facing the scales on the first stake and the second stake.

9. The method for measuring the relative relationship between piles in underwater pile group construction according to claim 1, characterized in that, In step S11, the ruler is pasted or painted on the pile body; there are multiple rulers, and the multiple rulers are arranged at intervals along the circumference of the pile body.

10. A system for measuring the relative relationship between piles in underwater pile group construction, characterized in that, The underwater pile group construction pile relative relationship measurement system, applicable to the method described in claim 8, comprises: Multiple scales are respectively set on the pile body of the first pile that has been driven and the pile body of the second pile to be driven; the scales extend downward from the top of the pile body, and the scales are provided with positioning points and multiple scale lines arranged vertically at intervals below the positioning points. A measurement platform is positioned between the location of the first pile that has already been driven and the location of the second pile to be driven; the measurement platform is an underwater robot. An underwater camera assembly is mounted on the measurement platform via a gimbal. The underwater camera assembly includes a first camera and a second camera arranged coaxially but facing away from each other. The first camera and the second camera are used to acquire images of scales on the first and second stakes, respectively. The gimbal is used to rotate the underwater camera assembly so that the first camera and the second camera are facing the scales on the first and second stakes, respectively. An attitude sensor is installed on the underwater camera assembly to acquire the attitude information of the underwater camera assembly in real time. An auxiliary light source is provided on the underwater camera assembly or the measurement platform. The processor is connected to the underwater camera group; the processor has a built-in computing unit and a control unit; the computing unit performs image enhancement and scale recognition on the scale images acquired by the first and second cameras, and calculates the horizontal distance and elevation difference between the second pile to be driven and the first pile that has already been driven, in combination with the attitude information of the underwater camera group; the control unit is used to control the rotation of the gimbal, control the start and stop of the shooting and measurement of the first and second cameras, and adjust the illumination of the auxiliary light source; A floating work platform is deployed above the water surface; the floating work platform is communicatively connected to a computing unit to obtain the calculation results of the computing unit in real time; the floating work platform is communicatively connected to a control unit to monitor the operation of the control unit; the floating work platform is communicatively connected to an underwater robot to remotely control the movement of the underwater robot.

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