Bridge high-precision automatic mapping method and system

Abstract

The embodiment of the application provides a kind of bridge high-precision automatic mapping method and system, belong to bridge mapping technical field.The method comprises: based on the laser guide beam of the mutual response between multiple space fixed anchor points and multiple bridge rigid joint anchor points pre-arranged in bridge structure, obtain the three-dimensional space correction framework covering target bridge;Identify the spatial state of each laser guide beam in the historical mapping data of corresponding bridge corresponding to each historical mapping moment;The three-dimensional space correction framework and the spatial state of each laser guide beam in the historical mapping data of corresponding bridge corresponding to each historical mapping moment are used as spatial reference constraint, historical mapping data correction is executed, and the corrected mapping data set is obtained;Based on the corrected mapping data set, the size parameters of each preset key structure unit of corresponding bridge at the current time are extracted.The application scheme significantly improves the spatial comparability and overall mapping accuracy of bridge cross-period data.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge mapping, in particular to a bridge high-precision automatic mapping method and a bridge high-precision automatic mapping system. BACKGROUND

[0002] As an important infrastructure for crossing rivers, valleys or roads, the structural safety of a bridge is directly related to the stable operation of the transportation system and the safety of public life and property. With the increase of service life and the accumulation of traffic load, the bridge structure is prone to subtle deformation, crack expansion or component displacement, and often shows millimeter to centimeter structural size changes. For the identification and trend judgment of such early diseases, high-precision structural mapping means must be relied on to achieve fine perception and continuous tracking of the geometric state of key components.

[0003] However, the existing bridge structure mapping technology generally faces two key problems. One is the lack of stable mapping mechanism that can maintain a high-precision reference benchmark for a long time. Traditional manual total station measurement, laser scanning, and structural camera modeling methods are limited by device drift, mapping position repeatability error, and bridge site environment disturbance, making it difficult to achieve sub-centimeter repeatability, especially when the bridge structure experiences periodic thermal expansion and contraction or traffic load disturbance, which can easily introduce uncontrollable errors and affect the accuracy of micro-deformation identification. The second is that in cross-period structure mapping, the lack of a unified spatial alignment benchmark makes it difficult to directly compare data between different time periods. Existing methods rely on GPS positioning, ground markers or static support points to restore the mapping posture, but these methods are subject to anchoring stability, device setup repeatability and external environment changes, often causing data from different mapping times to be expressed in different spatial coordinate systems, making it difficult to accurately reflect the structural size evolution trend.

[0004] Therefore, how to stably obtain high-precision and alignable mapping data of the bridge structure at multiple mapping times without repeatedly setting up temporary measurement benchmarks, and then identify centimeter-level or even millimeter-level structural changes, has become an important technical problem that needs to be solved in the current bridge monitoring field. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a bridge high-precision automatic mapping method and system to at least solve the problem that in the existing bridge structure mapping, a unified spatial benchmark cannot be maintained between multiple mapping times, resulting in inaccurate identification of structural size changes.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a bridge high-precision automatic mapping method, which comprises:

[0007] Based on the laser guide beams between the multiple spatial fixed anchor points and the multiple bridge rigid connection anchor points in the bridge structure, a three-dimensional spatial correction framework covering the target bridge is obtained;

[0008] The historical survey data corresponding to the bridge are collected, and the spatial states of the laser guide beams at the corresponding historical survey time points in the historical survey data corresponding to the bridge are identified;

[0009] The three-dimensional spatial correction framework and the spatial states of the laser guide beams at the corresponding historical survey time points in the historical survey data corresponding to the bridge are taken as spatial reference constraints to perform historical survey data correction, and a corrected survey data set is obtained;

[0010] Based on the corrected survey data set, the size parameters of each preset key structural unit of the corresponding bridge at the current time are extracted.

[0011] Optionally, the spatial fixed anchor point is an anchor point whose spatial position remains unchanged during the deformation process of the bridge structure, and is used to provide a stable three-dimensional coordinate reference;

[0012] The bridge rigid connection anchor point is an anchor point whose spatial position changes with the structural response during the deformation process of the bridge structure, and is used to represent the local response characteristics of the structure;

[0013] The installation position of each spatial fixed anchor point includes:

[0014] Any one or multiple positions of the top end of the center reinforcement cage of the pier cap beam, the lower transverse steel structure platform of the support, and the embedded plate in the concrete body of the main bridge anchoring segment;

[0015] The spatial fixed anchor point is rigidly connected to the corresponding installation position through an electric pan-tilt head;

[0016] The electric pan-tilt head has a three-degree-of-freedom attitude adjustment function and is provided with an attitude locking mechanism, which is used to ensure that the laser emitting device maintains a consistent spatial emission position between multiple survey time points.

[0017] Optionally, the construction rule of the laser guide beam is:

[0018] Each laser guide beam is formed by a laser transmission path between one spatial fixed anchor point and one bridge rigid connection anchor point;

[0019] Among them, one spatial fixed anchor point can form a laser guide beam with multiple bridge rigid connection anchor points, and one bridge rigid connection anchor point can form a laser guide beam with multiple spatial fixed anchor points;

[0020] Each laser guide beam is uniquely identified by a binary array generated by its corresponding spatial fixed anchor point and bridge rigid connection anchor point in the survey task;

[0021] Most of the binary array is used to bind the guide beam number and the spatial state information in the survey data acquisition and historical survey data correction process.

[0022] Optionally, historical survey data corresponding to the bridge is collected, and the spatial state of each laser guide beam at each historical survey time in the historical survey data corresponding to the bridge is identified, including:

[0023] Based on the bridge structure number, data records at multiple historical survey times are extracted from the structure maintenance database, and the data records include the irradiation state data of the historical laser guide beam consistent with the current laser guide beam number;

[0024] For the irradiation state data of each historical laser guide beam, index is performed according to the bound spatial fixed anchor point and the bridge rigid connection anchor point binary array number, and after successful indexing, the irradiation coordinates and attitude state at the corresponding historical survey time are obtained, forming a guide beam time sequence state matrix, which is the spatial state of the corresponding laser guide beam at the corresponding historical survey time in the historical survey data corresponding to the bridge.

[0025] Optionally, the three-dimensional space correction framework and the spatial state of each laser guide beam at each historical survey time in the historical survey data corresponding to the bridge are taken as a spatial reference constraint to perform historical survey data correction to obtain a corrected survey data set; including:

[0026] Taking the three-dimensional space correction framework constructed at the current survey time as an absolute coordinate reference, each survey time in the historical survey data is selected in turn, and the irradiation coordinates of each laser guide beam at the historical survey time and the current guide beam irradiation coordinates are calculated to generate a guide beam time difference vector field;

[0027] According to the laser guide beam binary array number, the guide beam time difference vector field is mapped, and the overall offset vector of each bridge rigid connection anchor point at the historical time is calculated according to the vector value of all guide beams associated with the bridge rigid connection anchor point;

[0028] Based on the offset vector of each bridge rigid connection anchor point, a continuous spatial offset field covering the entire structure surface is generated by interpolation;

[0029] Taking the offset field as a spatial reference constraint, coordinate re-projection and attitude registration operations are performed on the historical survey data point cloud and / or image data, and a historical survey data set consistent with the current correction framework is output as a corrected survey data set.

[0030] Optionally, based on the corrected survey data set, the size parameters of each preset key structure unit of the corresponding bridge at the current time are extracted, including:

[0031] Based on the corrected survey data set, under the constraint of the three-dimensional space correction framework, the spatial position area corresponding to each preset key structural unit at the current time is identified in turn;

[0032] For the spatial position area corresponding to the current time, the survey data in the coverage area is extracted, and the survey data is sequentially executed boundary fitting, normal analysis and curvature extraction to establish the geometric mathematical model of the corresponding preset key structural unit;

[0033] Based on the geometric mathematical model, the size information of the preset key structural unit in three orthogonal main directions is calculated as the extraction result;

[0034] The extraction result is packaged as a structure size parameter table at the current survey time, and unified coding and archiving are performed according to the coordinate system of the three-dimensional space correction framework.

[0035] Optionally, the extraction result includes:

[0036] Any one or more of the outer boundary size, the seam width, the surface deformation curvature radius and the structure opening angle.

[0037] Optionally, the method further includes:

[0038] A plurality of preset key structural units in a bridge structure are taken as monitoring objects, and based on the corrected survey data at a plurality of historical survey times, a dynamic deformation response surface of the structural unit is constructed, including:

[0039] Under the three-dimensional space correction framework, the surface point cloud or equivalent geometric description surface of each preset key structural unit at each historical survey time is extracted;

[0040] Difference analysis is performed on the structural unit surface data at each time to calculate the normal offset field and the curvature change index;

[0041] Each survey time is taken as a time dimension, a spatial position parameter is taken as a horizontal and vertical dimension, and a point cloud change amount is taken as a function value, to construct a three-dimensional response surface of the structural unit with respect to time variable, space variable and deformation variable;

[0042] Based on the three-dimensional response surface, a deformation rate field and an acceleration estimation model are established, and a prediction curve for identifying the nonlinear evolution trend of the structure response is output.

[0043] The second aspect of the present application provides a bridge high-precision automatic surveying and mapping system, the system includes:

[0044] The acquisition unit is used for obtaining a three-dimensional space correction framework covering the target bridge based on the laser guide beam responding to each other between the plurality of spatial fixed anchor points and the plurality of bridge rigid joint anchor points in the bridge structure.

[0045] a processing unit configured to collect historical survey data corresponding to the bridge and identify spatial states of the laser guide beams at historical survey time points in the historical survey data corresponding to the bridge;

[0046] a correction unit configured to perform historical survey data correction by taking the three-dimensional spatial correction framework and the spatial states of the laser guide beams at the historical survey time points in the historical survey data corresponding to the bridge as spatial reference constraints, and obtain a corrected survey data set;

[0047] an output unit configured to extract size parameters of each preset key structural unit of the bridge at the current time based on the corrected survey data set.

[0048] In another aspect, the present application provides a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, cause the computer to perform the bridge high-precision automatic surveying method described above.

[0049] Through the above technical solution, the present application scheme realizes a stable and traceable surveying and mapping reference system by pre-arranging a plurality of spatial fixed anchor points and a plurality of bridge rigid joint anchor points in the bridge structure, and constructing a three-dimensional spatial correction framework based on the laser guide beams formed therebetween. On this basis, by comparing the spatial states of the laser guide beams at the historical survey time and the current time, a unified spatial reference constraint is established, and the attitude drift and spatial offset problems in the historical survey data are effectively corrected to generate a corrected data set consistent with the current coordinate system. The scheme significantly improves the spatial comparability and overall surveying and mapping accuracy of cross-period data, and can realize millimeter-level to centimeter-level structural size change extraction, thereby providing high-precision and continuous basic data support for early identification and trend judgment of bridge diseases.

[0050] Other features and advantages of the present application will be described in detail in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings are included to provide a further understanding of the present application and constitute a part of the specification, which together with the detailed description, serve to explain the present application. The drawings illustrate embodiments of the present application and, together with the detailed description, serve to explain the present application. However, the present application is not limited to the accompanying drawings.

[0052] Figure 1 is a step flowchart of the bridge high-precision automatic surveying method provided by an embodiment of the present application;

[0053] Figure 2 is a schematic diagram of the setting positions of the anchor points provided by an embodiment of the present application;

[0054] Figure 3is a system structure diagram of a bridge high-precision automatic mapping system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0055] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0056] Figure 1 is a method flow chart of a bridge high-precision automatic mapping method provided by an embodiment of the present application. As shown in Figure 1 The embodiment of the present application provides a bridge high-precision automatic mapping method, which comprises the following steps.

[0057] Step S10: obtaining a three-dimensional space correction framework covering a target bridge based on laser guide beams responding to each other between a plurality of space fixed anchor points and a plurality of bridge rigid joint anchor points pre-arranged in a bridge structure.

[0058] Specifically, the space fixed anchor points are anchor points whose spatial positions remain unchanged during deformation of the bridge structure, and are used to provide stable three-dimensional coordinate reference; the bridge rigid joint anchor points are anchor points whose spatial positions change with the structure response during deformation of the bridge structure, and are used to represent local response characteristics of the structure; the installation positions of each space fixed anchor point include any one position or multiple positions in a center reinforcement cage top end of a pier cap beam, a lower transverse steel structure platform of a support, and a pre-embedded plate in a main bridge anchoring segment concrete body; the space fixed anchor points are arranged on the corresponding installation positions through a motorized pan-tilt head; the motorized pan-tilt head has a three-degree-of-freedom attitude adjustment function, and is provided with an attitude locking mechanism, which is used to ensure that the laser emitting device maintains a consistent spatial emission position between multiple mapping moments.

[0059] Further, the construction rule of the laser guide beams is that each laser guide beam is formed by a laser transmission path between one space fixed anchor point and one bridge rigid joint anchor point; wherein one space fixed anchor point can form laser guide beams with multiple bridge rigid joint anchor points respectively, and one bridge rigid joint anchor point can also form laser guide beams with multiple space fixed anchor points; each laser guide beam is uniquely identified by a binary array generated by its corresponding space fixed anchor point and bridge rigid joint anchor point in the mapping task; most binary arrays are used to bind the guide beam number and the space state information in the mapping data acquisition and historical mapping data correction processes.

[0060] In the embodiment of the present application, in the fine management process of the whole life cycle of the bridge structure, ensuring the consistency of the space reference between each mapping moment is the key basis for realizing millimeter-level or even centimeter-level deformation identification. Especially in the face of the structural response caused by temperature changes, load fluctuations, material aging and other factors in the long-term operation process of the bridge, the spatial scale evolution is often very small and widely distributed, and a stable, repeatable and accurate positioning spatial reference mechanism must be used to support the smooth development of high-precision mapping and trend analysis. Based on this demand, the present scheme proposes to build a laser guide beam network that responds to each other between multiple spatial fixed anchor points and multiple bridge rigid anchor points arranged in advance inside and outside the bridge structure, thereby establishing a three-dimensional spatial correction framework covering the entire target bridge, providing consistent spatial coordinate support for subsequent mapping data correction, structure size extraction and evolution analysis.

[0061] Specifically, the spatial fixed anchor point refers to an anchoring node whose spatial position remains unchanged during the deformation process of the bridge structure, and is mainly used to provide stable and reusable three-dimensional coordinate reference. The selection of these anchor points follows the principle of overall rigidity and negligible local deformation, and is preferentially arranged at the structure position that does not participate in the long-term response of the bridge live load. Specifically, but not limited to: the top end position of the center reinforcement cage of the pier cap beam, which is in the rigid central axis of the pile foundation and the superstructure, has a stable stress state and rarely occurs transverse or vertical displacement; the lower transverse steel structure platform of the support, which is usually a rigid transition structure between the bridge support system and the pier, has good installation conditions and structural stability; the embedded plate position in the concrete body of the main bridge anchoring section, which is suitable for long-term positioning reference of the anchor point due to its low deformation amplitude compared to the active components.

[0062] To realize high-precision orientation and repeated projection of the anchor point, each spatial fixed anchor point is installed on the selected structure part through a rigidly connected motorized pan-tilt. The motorized pan-tilt has three-degree-of-freedom attitude adjustment capability, which can realize micron-level adjustment accuracy in pitch, yaw and roll directions to cope with installation errors and on-site construction deviations. At the same time, the motorized pan-tilt is provided with a high locking precision attitude locking mechanism for keeping the spatial attitude of the laser emitting device unchanged between multiple mapping tasks, ensuring that the laser beam is emitted from the same spatial emission point in each mapping, and avoiding measurement drift caused by small device shaking, thermal expansion and contraction or repeated erection errors. For example Figure 2An embodiment gives the setting position of each anchor point. The spatial fixed anchor point is preferably installed in the position of stable geometry and long-term unchanged stress state in the bridge structure, such as the top of the main tower, the platform of the anchoring section or the steel structure platform under the support, for providing stable spatial coordinate reference. The bridge rigid connection anchor point is installed in the structure response active area such as the end of the bridge deck, the edge of the expansion joint or the suspension cable connection node, and its spatial position can be displaced by the small deformation of the bridge, for characterizing the local response behavior of the structure. The above two types of anchor points are arranged in pairs according to the predetermined layout rule, and the laser guide beam is arranged between them to form a spatial geometric constraint network covering the entire bridge deck, providing three-dimensional spatial reference support for subsequent point cloud correction, image pose registration and size parameter extraction processes.

[0063] Another type of key node cooperating with the spatial fixed anchor point is the bridge rigid connection anchor point. This type of anchor point is specially set in the position highly sensitive to deformation response in the bridge structure, and its spatial position will change measurably with the physical deformation of the bridge itself in the operation process, thereby characterizing the response characteristics of the local structure. The layout position of this type of anchor point is usually selected in the structure weak or deformation significant area such as the expansion joint, the beam end, the web junction, the arch top and the main span web edge connection zone, and the anchoring mode is set in the surface embedded bar node or the reserved positioning hole according to the structure safety requirement, to ensure reliable installation without damaging the structure body.

[0064] After the layout is completed, a laser emitting device and a target reflection component or a highly reflective film are used to construct a laser guide beam between the spatial fixed anchor points and the bridge rigid connection anchor points. Each guide beam is composed of a unique corresponding spatial fixed anchor point and bridge rigid connection anchor point, forming a laser path with directionality and spatial continuity. The laser guide beam not only provides a laser geometric projection reference in the surveying process, but also reflects the spatial displacement of the structure response at different positions in real time through the spatial coordinate change of the laser spot on the target surface, thereby supporting high-precision structure behavior restoration.

[0065] To ensure the organization logic of the laser guide beam network is clear and the identification is unique, a binary array of "[spatial fixed anchor point number, bridge rigid connection anchor point number]" is used to encode and identify each guide beam in the surveying task. For example, the guide beam between the spatial fixed anchor point numbered F1 and the bridge rigid connection anchor point numbered M7 is uniquely identified as {F1, M7}. The identification not only binds the spatial response relationship between the laser device emitting path and the target reflection point in the data acquisition stage, but also serves as the key time sequence and spatial index basis in the subsequent historical surveying data correction and structure response surface reconstruction, realizing automatic pairing and continuity processing of cross-period and multi-source data.

[0066] It is worth noting that one space fixed anchor point can form multiple guide beams with multiple bridge rigid anchor points at the same time, for covering different structural areas or layered structural units; similarly, one bridge rigid anchor point can also be irradiated by multiple space fixed anchor points at the same time, forming a spatial redundant path. This multi-to-multi guide beam layout structure has high redundancy and spatial resolution, and when an individual guide beam is temporarily disabled due to external obstruction, target loss, etc., the adjacent guide beams can still achieve spatial fitting and coordinate calculation of the target area, significantly enhancing the robustness and fault tolerance of the mapping framework.

[0067] The three-dimensional space correction framework constructed by the above-mentioned space fixed anchor point, bridge rigid anchor point and laser guide beam can provide a highly consistent spatial reference system in the entire bridge mapping area. Whether it is initial mapping or subsequent regular re-measurement, the point cloud data, image data or laser distance data collected by the mapping equipment can be projected into a unified coordinate system by restoring the spatial geometric relationship according to the irradiation state of the laser guide beam, effectively eliminating errors caused by differences in mapping equipment erection, attitude drift or external disturbances, and ensuring that millimeter-level to centimeter-level structural deformation or size changes can be accurately captured and quantitatively analyzed.

[0068] In summary, the present scheme constructs a bridge space correction framework based on laser guide beams, which not only solves the problem of non-reproducible spatial coordinate system in bridge multi-time mapping, but also provides high stability, high consistency and high spatial resolution support conditions for micro-deformation structure monitoring. The scheme has strong universality, modular scalability and flexibility in field deployment, and is especially suitable for long-term state monitoring and early disease identification of long and large bridges, complex structural nodes and periodic deformation areas.

[0069] Step S20: Collect historical mapping data corresponding to the bridge, and identify the spatial state of each laser guide beam at each historical mapping time in the historical mapping data corresponding to the bridge.

[0070] Specifically, based on the bridge structure number, multiple historical mapping time data records are extracted from the structure maintenance database, the data records including the irradiation state data of the historical laser guide beams consistent with the current laser guide beam number; for the irradiation state data of each historical laser guide beam, the index is executed according to the bound space fixed anchor point and bridge rigid anchor point binary array number, and after successful indexing, the irradiation coordinates and attitude state at the corresponding historical mapping time are obtained, forming a guide beam time sequence state matrix as the spatial state of the corresponding laser guide beam at the corresponding historical mapping time in the historical mapping data corresponding to the bridge.

[0071] In the embodiment of the application, in the process of realizing high-precision mapping of bridge structure at multiple times, in order to establish a consistent spatial data comparison basis across time periods, the key spatial constraint elements in historical mapping data must be effectively recovered and analyzed. Among them, the laser guide beam as a geometric reference component in the three-dimensional space correction framework, its irradiation state (including irradiation position, direction and spatial attitude) in the historical mapping process constitutes an indispensable reference basis for correction mapping data. Therefore, in the existing bridge structure data platform, the spatial state of each laser guide beam at different historical mapping times must be accurately extracted and restored to support subsequent spatial reference constraint construction and coordinate system unification operation.

[0072] Specifically, the unique identification number of the bridge structure (such as the structure code or project ID) should be used as the index condition to access the bridge maintenance database or structure monitoring data warehouse first, and the multi-time historical mapping data records corresponding to the bridge are extracted from it. These records usually include laser scanning data, image mapping data, point cloud original files, auxiliary attitude files, and guide beam irradiation state files, etc., among which the guide beam irradiation state file is the focus of this stage analysis. The guide beam irradiation state data is the geometric response record of each laser guide beam at a specific mapping time in the mapping process, usually indexed by time stamp, containing the irradiation starting position (the spatial coordinates of the laser emission source), the irradiation direction vector (unit vector form), the laser endpoint echo position, the laser energy intensity, the target reflection state, the environmental temperature and humidity, etc., which are used to fully describe the propagation state of the guide beam in space.

[0073] After data extraction, the number consistency of each historical laser guide beam should be checked. For this purpose, the binary array number structure of the laser guide beam agreed upon in the mapping stage, i.e. using "{spatial fixed anchor point number, bridge rigid anchor point number}" as a unique identifier, is used as an index basis for matching. Through the binding and matching of the binary array number with the guide beam state records stored in the database, it is ensured that the extracted data and the current object to be corrected have an explicit logical correspondence. For the records that match successfully, the state parameters of the guide beam at multiple historical mapping times need to be further read.

[0074] For each laser guide beam, based on the time sequence order, the irradiation state data of the guide beam at each historical mapping time is sorted along the time axis to form a corresponding guide beam time sequence state matrix. Each row of the matrix represents the irradiation state of the guide beam in a mapping task, including the following fields: mapping time identifier (for example, in the format of YYYYMMDD_HHMMSS), spatial coordinates of the laser emission source (X1, Y1, Z1), irradiation direction unit vector (dx, dy, dz), end point echo position coordinates (X2, Y2, Z2), optical path length L, environmental temperature and humidity compensation value Tcorr, and device attitude during irradiation (including pitch angle, yaw angle, and roll angle). The matrix structure is as follows:

[0075] | Time ID | X1 | Y1 | Z1 | dx | dy | dz | X2 | Y2 | Z2 | L | Tcorr | Pitch | Yaw | Roll |

[0076] The guide beam time sequence state matrix is used to describe the spatial evolution characteristics of a certain laser guide beam in the corresponding bridge at multiple mapping times, and can provide detailed spatial input basis for subsequent spatial error analysis, attitude recovery, point cloud registration and correction operations. At the same time, through this hierarchical structure organization method, the standardized retrieval and automatic batch processing of laser guide beam irradiation data can be realized in complex bridge monitoring projects, laying a structured foundation for consistency analysis of long-term monitoring data.

[0077] The processing flow not only ensures that the laser guide beams in different historical mapping data can be accurately restored and reused according to the current spatial correction framework, but also realizes the conversion from time-distributed scattered point data to continuous comparable vector state through complete attitude and coordinate records, providing high-precision and stable basic data support for the construction of spatial reference constraints. In this way, it can effectively support the recovery and trend extraction of structural responses at the scale of millimeters to centimeters, and is particularly suitable for application scenarios such as early disease identification of bridge structures, periodic response monitoring, and spatial alignment evolution analysis.

[0078] Step S30: Taking the three-dimensional spatial correction framework and the spatial state of each laser guide beam at each historical mapping time in the historical mapping data of the corresponding bridge as a spatial reference constraint, performing historical mapping data correction to obtain a corrected mapping data set.

[0079] Specifically, the three-dimensional space correction framework constructed at the current surveying time is taken as the absolute coordinate reference, each surveying time in the historical surveying data is selected in turn, the irradiation coordinates of each laser guide beam at the historical surveying time and the current guide beam irradiation coordinates are calculated by space vector difference, and a guide beam time difference vector field is generated; the guide beam time difference vector field is executed by structure mapping according to the binary array number of the laser guide beam, and the overall offset vector of each bridge rigid connection anchor point at the historical time is calculated according to the vector value of all the guide beams associated with the bridge rigid connection anchor point; based on the offset vector of each bridge rigid connection anchor point, a continuous space offset field covering the entire structure surface is generated by interpolation; the offset field is taken as a spatial reference constraint, and the coordinate re-projection and attitude registration operation of the historical surveying data point cloud and / or image data is executed, and the historical surveying data set consistent with the current correction framework is output as the corrected surveying data set.

[0080] In the embodiment of the application, in the long-term monitoring and maintenance work of the bridge structure, the slight deformation of the structure parts evolved over time is of key significance to the identification of early diseases. However, the surveying data collected at different times often cannot keep consistent in spatial reference due to differences in surveying equipment erection, attitude changes or external environmental interference, resulting in that the subsequent data cannot be compared with high precision. The present embodiment realizes the geometric error correction and attitude standardization processing of the historical surveying data by establishing a unified three-dimensional space correction framework and taking the time sequence space state of the historical laser guide beam as a spatial reference constraint, and finally outputs a set of corrected surveying data set aligned with the current correction framework, which can be used for precise comparative analysis.

[0081] Specifically, in the current surveying task, based on the laser guide beam network constructed between the multiple space fixed anchor points and the multiple bridge rigid connection anchor points, a three-dimensional space correction framework covering the target bridge has been obtained. The correction framework has clear spatial definition and coordinate integrity at the current surveying time, and can be taken as the unified absolute space reference of the whole bridge structure. On this basis, in order to realize the correction processing of the historical surveying data, the current correction framework needs to be taken as a reference to process the space state of each historical surveying time in turn, and gradually build the corrected data consistent with the current coordinate system.

[0082] Firstly, the space state of each historical surveying time is selected from the historical surveying data set in chronological order, and the coordinate difference of each laser guide beam is analyzed. The irradiation coordinates of the laser beam numbered {Fi, Mj} at the current time are Pcur(Fi, Mj), and the corresponding irradiation coordinates at the historical time are The space vector difference between the two can be expressed as:

[0083] ;

[0084] The vector difference AV represents the change in the illumination path of the guide beam between the same pair of anchor points due to the change in the bridge structure response, which can be regarded as the time difference vector response of the guide beam between the current and historical time.

[0085] Secondly, the guide beam time difference vector data is mapped according to the binary array number {Fi, Mj} to which it belongs. That is, the vector differences AV1, AV2,... corresponding to the guide beam sets {Fi1, Mj}, {Fi2, Mj},... associated with the same bridge rigid connection anchor point Mj are weighted and integrated to calculate the overall spatial displacement vector T(Mj, tk) of the bridge rigid connection anchor point Mj at the historical time tk. The calculation can be realized in the following way:

[0086]

[0087] The weight ωi can be set based on the guide beam projection angle, reflection intensity or historical data reliability to enhance the data stability and the ability to reflect the actual displacement trend.

[0088] Thirdly, the spatial displacement vectors {T(M1, tk), T(M2, tk),..., T(Mn, tk)} of all bridge rigid connection anchor points at the historical time are used as interpolation nodes to construct a continuous spatial displacement field F(tk, x, y, z) covering the entire bridge structure surface by using polynomial interpolation, spline interpolation or triangular net (TIN) interpolation algorithm. The displacement field is a three-dimensional vector field, and the spatial displacement of each point P(x, y, z) is determined by the interpolation of its surrounding anchor point vectors, ensuring the spatial continuity and local precision control ability of the displacement estimation.

[0089] Fourthly, the displacement field is used as the basis for geometric correction of historical survey data to perform spatial re-projection and attitude correction operation on the original survey data (including point cloud data, image data, laser ranging data, etc.) collected at the historical time. For each survey data point Qhist(x, y, z), according to its corresponding position in the displacement field, it is corrected to:

[0090]

[0091] If the point is accompanied by attitude information (such as camera pose, radar scanning direction, etc.), the attitude matrix can also be adjusted according to the guide beam direction transformation relationship to make the attitude projection plane of the point cloud or image consistent with the current time.

[0092] After the above steps are completed, the spatially corrected surveying and mapping data set at the historical time tk can be obtained. After sequentially processing all historical times, the unified spatial reference correction of the entire set of historical surveying and mapping data is completed, forming a set of corrected data sets consistent with the current correction framework space. The data set can be directly used for statistical analysis of the size change trend of the bridge structure, construction of the time sequence curve of deformation monitoring, long-term evolution modeling of the disease position, and other refined evaluation tasks.

[0093] Step S40: Based on the corrected surveying and mapping data set, the size parameters of each preset key structural unit of the bridge at the current time are extracted.

[0094] Specifically, based on the corrected surveying and mapping data set, under the constraint of the three-dimensional spatial correction framework, the spatial position region corresponding to each preset key structural unit at the current time is sequentially identified; for the spatial position region corresponding to the current time, the surveying and mapping data in the coverage region is extracted, and the surveying and mapping data is sequentially executed boundary fitting, normal analysis and curvature extraction to establish a geometric mathematical model of the corresponding preset key structural unit; based on the geometric mathematical model, the size information of the preset key structural unit in three orthogonal main directions is calculated respectively as the extraction result; the extraction result is packaged as a structure size parameter table at the current surveying and mapping time, and unified coding and archiving are performed according to the coordinate system of the three-dimensional spatial correction framework.

[0095] Further, the extraction result includes any one or more of the following: an outer package boundary size, a seam width, a surface deformation curvature radius, and a structure opening angle.

[0096] In the embodiment of the application, in the high-precision automatic surveying and mapping process of the bridge structure, after the spatial correction of the historical surveying and mapping data is completed, the size parameters of each key structural unit need to be further extracted based on the corrected surveying and mapping data set for structure state analysis, deformation trend identification, and disease evolution modeling and other applications. Due to the characteristics of the bridge structure, such as complex component types, large spatial scale, and significant differences in survey area morphology, the extraction of size parameters must be based on accurate control of spatial position, combined with structure characteristics to implement differentiated data processing and modeling process. The present embodiment sequentially completes the positioning, data extraction, geometric modeling and size calculation of the key structural unit based on the spatial constraint of the three-dimensional spatial correction framework, ensuring that the extraction result of the structure size parameter has a unified coordinate reference, clear structure attribution, and geometric precision of centimeter to millimeter.

[0097] Specifically, first, on the basis of the corrected survey data set, the spatial position area of each preset key structural unit is identified according to the design model or structure number table of the bridge structure. The key structural unit usually includes expansion joints, support connection areas, main beam midspans, pier and bent cap junctions, guardrail components, connection nodes and the like, which play a key role in structural performance and are high-risk areas of deformation, cracking and disease. By calling the center coordinates, boundary dimensions and elevation information in the structural design drawings, combined with the coordinate system of the current three-dimensional space correction frame, the spatial range of each structural unit in the corrected survey data can be located to form the extraction window or voxel bounding box of the structural unit.

[0098] Subsequently, for the survey data (including point cloud data, image reconstruction data or laser ranging data) in the above extraction window, three-stage processing operations of boundary fitting, normal analysis and curvature extraction are sequentially performed. The boundary fitting step mainly performs point cloud clustering and surface envelope reconstruction on the structural contour in the survey area, and the commonly used methods include RANSAC-based fitting model selection, B-spline envelope line fitting and three-dimensional Alpha Shape boundary reconstruction algorithm; the normal analysis is used to identify the spatial orientation and local concave-convex features of the structural surface, and is usually realized by point cloud normal estimation (such as PCA or Covariance analysis); and the curvature extraction further depicts the small deformation features of the structural surface, such as using Gaussian curvature or principal curvature radius analysis method to judge the structural curvature abnormal points and deformation trend. These steps form a closed-loop processing chain from raw data to geometric modeling, and establish a three-dimensional geometric mathematical model of the structural unit at the current time.

[0099] After the geometric modeling is completed, the structural size information can be extracted based on the model parameters. Taking the main beam midspan as an example, its size parameters can include the outer bounding length, midspan deflection, cross-section height variation and the like; for the bridge deck expansion joint, the joint width, linearity error of the joint boundary and opening angle are mainly extracted; for the support connection area, the included angle between the contact surfaces, indentation depth and support gap and the like need to be calculated. In order to realize standardized output, it is suggested to extract the corresponding size values in three orthogonal principal directions (such as bridge longitudinal direction X, transverse direction Y and vertical direction Z) respectively, and record them in the size parameter table with the unique code of the structural unit as the index.

[0100] The size parameter table includes the structural unit number, extraction time, survey data source ID, outer bounding size (such as length, width, height), joint width (such as opening and closing variation), surface curvature radius (such as concave-convex degree variation), opening and closing angle (such as the included angle change between structural surfaces) and the like, and the corresponding spatial reference coordinate system information is labeled.

[0101] Preferably, the method further comprises: taking a plurality of preset key structural units in the bridge structure as monitoring objects, and constructing a dynamic deformation response surface of the structural units based on the corrected mapping data of the plurality of historical mapping moments, comprising: in a three-dimensional space correction framework, taking each preset key structural unit as a unit, extracting the surface point cloud or equivalent geometric description surface thereof at each historical mapping moment; performing difference analysis on the structural unit surface data at each moment, calculating the normal offset field and the curvature change index; taking each mapping moment as the time dimension, taking the spatial position parameter as the horizontal and vertical dimensions, and taking the point cloud change as the function value, constructing a three-dimensional response surface of the structural unit with respect to the time variable, the spatial variable and the deformation variable; and based on the three-dimensional response surface, establishing a deformation rate field and an acceleration estimation model, and outputting a prediction curve for identifying the nonlinear evolution trend of the structural response.

[0102] In the embodiment of the present application, spatial consistency matching operation is performed on each preset key structural unit based on the three-dimensional space correction framework. The key structural unit includes but is not limited to: expansion joint edge segment, bearing support pressure area, main beam mid-span deflection segment, pier-cap beam joint, and other structural positions with clear structure and sensitive deformation. Through the corrected mapping data set, point cloud data or equivalent reconstructed geometric surface model of each structural unit at each historical mapping moment is extracted. The spatial reference coordinates of the point cloud data are unified to the three-dimensional space correction framework, so that the cross-time mapping data has strict consistency.

[0103] On this basis, difference analysis of the structural surface between the cross-time is performed. The normal direction is taken as the main analysis direction, and the normal offset calculation is performed on the reconstructed point cloud or geometric surface of each structural unit surface, that is, the vector difference calculation is performed on the corresponding points at adjacent moments, and the normal offset is extracted. At the same time, the curvature change index such as the difference of the Gaussian curvature, the average curvature or the principal curvature radius is calculated to judge whether the structural surface has local convex-concave change, warping, cracking and other phenomena. The offset field and the curvature change field jointly constitute the spatial response quantity of the structural unit at multiple moments.

[0104] Taking the time information as the vertical axis dimension and the structural space position as the horizontal coordinate axis (which can be discretized as grid points), the offset or curvature response at each moment is taken as the function value, and the three-dimensional response surface function model of the structural unit is constructed. The response surface is defined in the form of f(x, y, t), wherein (x, y) is the position of a certain spatial point on the structural unit in the three-dimensional correction coordinate system, t represents the mapping moment, and f represents the deformation variable or the normal offset value of the point at the moment t. The function model realizes continuous surface construction through spline interpolation, least square fitting or tensor reconstruction, and supports spatial response analysis changing with time.

[0105] Further, derivative calculation in the time axis direction is performed on the constructed three-dimensional response surface to obtain the structural response change rate field in unit time, i.e.

[0106]

[0107] If the second-order time derivative is further calculated:

[0108]

[0109] The acceleration field of the structural deformation can be obtained. These change rates and acceleration information help to identify whether there is a mutation in the structural response, a critical state is approaching, and other nonlinear evolution behaviors, and provide a data basis for the prediction modeling of disease development. Finally, the trend extraction of the time-space-deformation coupling model of the structural unit is performed, and the prediction curve representing the structural evolution trend is output, supporting the structural risk warning or maintenance decision in the form of "maximum deformation in the next week", "position where curvature mutation is about to occur", "seam opening speed greater than the threshold", etc.

[0110] Figure 3 is the system structure diagram of a bridge high-precision automatic mapping system provided by an embodiment of the present application. As shown in Figure 3 The embodiment of the present application provides a bridge high-precision automatic mapping system, which comprises: a collection unit, configured to obtain a three-dimensional space correction framework covering a target bridge based on laser guide beams responding to each other between a plurality of spatial fixed anchor points and a plurality of bridge rigid joint anchor points in a bridge structure; a processing unit, configured to collect historical mapping data corresponding to the bridge, and identify the spatial state of each laser guide beam corresponding to each historical mapping time in the historical mapping data corresponding to the bridge; a correction unit, configured to take the three-dimensional space correction framework and the spatial state of each laser guide beam corresponding to each historical mapping time in the historical mapping data corresponding to the bridge as a spatial reference constraint, perform historical mapping data correction, and obtain a corrected mapping data set; and an output unit, configured to extract the size parameters of each preset key structural unit of the corresponding bridge at the current time based on the corrected mapping data set.

[0111] The embodiment of the present application further provides a computer readable storage medium, which stores instructions, and when the instructions are run on a computer, the computer performs the above-mentioned bridge high-precision automatic mapping method.

[0112] Those skilled in the art can understand that all or part of the steps of the method for implementing the above-mentioned embodiments can be completed by programs instructing relevant hardware, the programs are stored in a storage medium, and the programs include a plurality of instructions for enabling a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various storage media capable of storing program codes.

[0113] The optional embodiments of the present application are described in detail above in combination with the drawings, but the embodiments of the present application are not limited to the specific details in the above-described embodiments. Within the technical concept scope of the embodiments of the present application, various simple modifications can be made to the technical solutions of the embodiments of the present application, and these simple modifications all belong to the protection scope of the embodiments of the present application. In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present application will not be described again for various possible combinations.

[0114] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the embodiments of the present application, and it should also be considered as disclosed by the embodiments of the present application.

Claims

1. A high-precision automatic mapping method for bridges, characterized by, The method comprises: Based on the mutual response laser guide beams between the multiple spatial fixed anchor points and the multiple bridge rigid connection anchor points pre-arranged in the bridge structure, a three-dimensional spatial correction framework covering the target bridge is obtained; wherein, The spatial fixed anchor point is an anchor point whose spatial position remains unchanged during the deformation process of the bridge structure, and is used to provide a stable three-dimensional coordinate reference; The bridge rigid connection anchor point is an anchor point whose spatial position changes with the structural response during the deformation process of the bridge structure, and is used to represent the local response characteristics of the structure; The installation position of each spatial fixed anchor point includes any one position or multiple positions of the top end of the center reinforcement cage of the pier cap beam, the lower transverse steel structure platform of the support, and the pre-embedded plate in the concrete body of the main bridge anchoring section; the spatial fixed anchor point is arranged on the corresponding installation position through a motorized pan-tilt head; the motorized pan-tilt head has a three-degree-of-freedom attitude adjustment function and is provided with an attitude locking mechanism for ensuring that the laser emitting device maintains a consistent spatial emission position between multiple surveying and mapping moments; The historical surveying and mapping data of the corresponding bridge are collected, and the spatial state of each laser guide beam corresponding to each historical surveying and mapping moment in the historical surveying and mapping data of the corresponding bridge is identified; The three-dimensional spatial correction framework and the spatial state of each laser guide beam corresponding to each historical surveying and mapping moment in the historical surveying and mapping data of the corresponding bridge are taken as spatial reference constraints to perform historical surveying and mapping data correction, and a corrected surveying and mapping data set is obtained; Based on the corrected surveying and mapping data set, the size parameters of each preset key structural unit of the corresponding bridge at the current moment are extracted.

2. The method of claim 1, wherein, The construction rule of the laser guide beam is: Each laser guide beam is formed by a laser transmission path between a spatial fixed anchor point and a bridge rigid connection anchor point; Wherein, one spatial fixed anchor point can form laser guide beams with multiple bridge rigid connection anchor points, and one bridge rigid connection anchor point can form laser guide beams with multiple spatial fixed anchor points; Each laser guide beam is uniquely identified by the binary array generated by its corresponding spatial fixed anchor point and bridge rigid connection anchor point in the surveying and mapping task; Most binary arrays are used to bind the guide beam number and the spatial state information in the surveying and mapping data collection and historical surveying and mapping data correction process.

3. The method of claim 1, wherein, The historical surveying and mapping data of the corresponding bridge are collected, and the spatial state of each laser guide beam corresponding to each historical surveying and mapping moment in the historical surveying and mapping data of the corresponding bridge is identified, including: Based on the bridge structure number, data records at multiple historical surveying and mapping moments are extracted from the structure maintenance database, and the data records include the illumination state data of the historical laser guide beams consistent with the current laser guide beam number; For the illumination state data of each historical laser guide beam, the spatial fixed anchor point and the bridge rigid connection anchor point binary array number are indexed according to the bound, and after successful indexing, the illumination coordinates and attitude state at the corresponding historical surveying and mapping moment are obtained to form a guide beam time sequence state matrix as the spatial state of the corresponding laser guide beam in the historical surveying and mapping data of the corresponding bridge at the corresponding historical surveying and mapping moment.

4. The method of claim 3, wherein, The three-dimensional space correction framework and each laser guide beam are constrained by the space state of the corresponding historical surveying and mapping data of the corresponding bridge at each historical surveying and mapping time, historical surveying and mapping data correction is performed, and a corrected surveying and mapping data set is obtained; the method comprises the following steps: Taking the three-dimensional space correction framework constructed at the current surveying and mapping time as an absolute coordinate reference, each surveying and mapping time in the historical surveying and mapping data is selected in turn, the irradiation coordinates of each laser guide beam at the historical surveying and mapping time are calculated, and a guide beam time difference vector field is generated; According to the binary array number of the laser guide beam, the guide beam time difference vector field is subjected to structure mapping, and the overall offset vector of each bridge rigid connection anchor point at the historical time is calculated according to the vector values of all the guide beams associated with the bridge rigid connection anchor point; Based on the offset vectors of each bridge rigid connection anchor point, a continuous space offset field covering the entire structure surface is generated by interpolation; Taking the offset field as a space reference constraint, coordinate re-projection and attitude registration operations are performed on the historical surveying and mapping data point cloud and / or image data, and a historical surveying and mapping data set consistent with the current correction framework is output as a corrected surveying and mapping data set.

5. The method of claim 1, wherein, Based on the corrected surveying and mapping data set, the size parameters of each preset key structure unit of the corresponding bridge at the current time are extracted, which comprises the following steps: Based on the corrected surveying and mapping data set, the spatial position region corresponding to each preset key structure unit at the current time is identified under the constraint of the three-dimensional space correction framework; For the spatial position region corresponding to the current time, the surveying and mapping data in the region is extracted, and the surveying and mapping data is subjected to boundary fitting, normal analysis and curvature extraction in turn to establish a geometric mathematical model of the corresponding preset key structure unit; Based on the geometric mathematical model, the size information of the preset key structure unit in three orthogonal main directions is calculated respectively as the extraction result; The extraction result is packaged as a structure size parameter table at the current surveying and mapping time, and unified coding and archiving are performed according to the coordinate system of the three-dimensional space correction framework.

6. The method of claim 5, wherein, The extraction result comprises: Any one or more of the outer boundary size, the seam width, the surface deformation curvature radius and the structure opening angle.

7. The method of claim 1, wherein, The method further comprises: Taking a plurality of preset key structure units in the bridge structure as monitoring objects, a dynamic deformation response surface of the structure unit is constructed based on the corrected surveying and mapping data at a plurality of historical surveying and mapping times, which comprises the following steps: Under the three-dimensional space correction framework, the surface point cloud or equivalent geometric description surface of each preset key structure unit at each historical surveying and mapping time is extracted; Difference analysis is performed on the surface data of the structure unit at each time, and the normal offset field and the curvature change index are calculated; Taking each surveying and mapping time as a time dimension, taking a spatial position parameter as a horizontal and vertical dimension, and taking a point cloud change as a function value, a three-dimensional response surface of the structure unit with respect to time variable, space variable and deformation variable is constructed; Based on the three-dimensional response surface, a deformation rate field and an acceleration estimation model are established, and a prediction curve for identifying the nonlinear evolution trend of the structure response is output.

8. A high-precision automatic mapping system for bridges, characterized in that it comprises: The system is used for performing the bridge high-precision automatic mapping method in any one of claims 1-7, and the system comprises: An acquisition unit is configured to obtain a three-dimensional space correction framework covering a target bridge based on laser guide beams responding to each other between a plurality of space fixed anchor points and a plurality of bridge rigid joint anchor points pre-arranged in a bridge structure; A processing unit is configured to acquire historical mapping data of a corresponding bridge and identify spatial states of each laser guide beam at each historical mapping time in the historical mapping data of the corresponding bridge; A correction unit is configured to correct the historical mapping data by taking the three-dimensional space correction framework and the spatial states of each laser guide beam at each historical mapping time in the historical mapping data of the corresponding bridge as a spatial reference constraint, and obtain a corrected mapping data set; An output unit is configured to extract size parameters of each preset key structure unit of the corresponding bridge at a current time based on the corrected mapping data set.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions, which, when executed on a computer, cause the computer to perform the bridge high-precision automatic mapping method in any one of claims 1-7.

Images