Method for processing three-dimensional laser scanning point cloud data of concrete form, and method and device for detecting concrete form based on three-dimensional laser scanning

Abstract

The application discloses a three-dimensional laser scanning point cloud data processing method for a concrete form, a concrete form detection method and device based on three-dimensional laser scanning, and solves the problem that a large amount of interference data in original point cloud data needs to be manually cleaned. The method comprises the following steps: when a three-dimensional laser scanner scans a to-be-detected concrete form in a set scanning mode at a set measurement position, each sampling point data collected and sent in real time by the three-dimensional laser scanner is synchronously received; position information of a corresponding sampling point is extracted in real time, and it is determined whether the position of the sampling point falls into a set key area of shape and position control of the concrete form according to the position information; if the determination result is yes, the sampling point data is stored as target point data in a target point data buffer area; if the determination result is no, the sampling point data is discarded; and after the scanning is completed, a data processing result is obtained according to all the target point data stored in the target point data buffer area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quality detection of building concrete (hereinafter referred to as concrete), and in particular to a concrete formwork three-dimensional laser scanning point cloud data processing method, a concrete formwork detection method and device based on three-dimensional laser scanning. BACKGROUND

[0002] With the development of modern building technology, the design of large public buildings is increasingly complex and artistic. Among them, the structure of cast-in-place formwork with fair-faced concrete is favored for its unique decorative effect. At present, in a large public building constructed by the applicant, an internal arch corridor group composed of a large number of arch corridors arranged in a horizontal and vertical staggered manner is required to be constructed (see Figure 6 ), and more strictly, the structure requires cast-in-place formwork with fair-faced concrete, and the natural texture of fair-faced concrete is directly used as the final interior and exterior finish of the building. This means that the precision requirement of the concrete formwork project is very high, and even a small flaw can affect the appearance.

[0003] In order to meet this challenge, a highly customized concrete formwork is used. In the concrete formwork, each large face of the concrete formwork needs to be curved into an accurate arc according to the design requirements, and is supported and profiled by the concrete formwork shaping pre-tightening force mechanism and the shaped keel densely arranged on the back of the concrete formwork. In the direction along the curved contour line of the concrete formwork, a plurality of concrete formwork shaping pre-tightening force mechanisms (pre-stressed screws) are arranged at intervals, and each concrete formwork shaping pre-tightening force mechanism is controlled by an independent pre-tightening force adjusting device (locking nut), so that the concrete formwork is subjected to accurate and dispersed forces to produce accurate elastic deformation, so that the large face plate of the concrete formwork perfectly fits the preset profile of the shaped keel.

[0004] In the face of complex and highly precise concrete formwork, three-dimensional laser scanning is required for concrete formwork detection. However, the three-dimensional laser scanning technology faces the following problems in actual application:

[0005] First, in the measurement site, the field of view of the three-dimensional laser scanner is filled with a maze-like scaffold system erected to support the concrete formwork, and the concrete formwork shaping pre-tightening force mechanism and the shaped keel densely arranged on the back of the concrete formwork supported by the scaffold system. The point cloud data of these structures completely overwhelms the point cloud of the large face of the concrete formwork that needs to be analyzed in terms of quantity, resulting in most of the data in the original point cloud data being "interference data" that is not related to the shape and position control. This not only makes the data volume of a single scan large, causing a burden on data transmission and storage, but also affects the detection efficiency.

[0006] Secondly, due to the interference structure such as keel, concrete formwork shaping pre-tightening force mechanism and the like closely adhering to the concrete formwork large surface in space, the point cloud of the interference structure and the point cloud of the concrete formwork large surface are closely coupled or even mostly overlapped in space, and the automatic or semi-automatic filtering and segmentation algorithm in the traditional point cloud processing software is basically invalid in this scenario. The current method is to rely on technical personnel to manually "clean up", that is, to manually frame and delete the interference data points on the computer to extract the formwork large surface point cloud for analysis. This process not only consumes time and effort, but also is prone to incorrect selection or omission due to human operation, affecting the accuracy of the final analysis results.

[0007] Thirdly, the traditional workflow of the three-dimensional laser scanning operation of such a large building structure is "complete scanning on site → data copying → post-processing in office → generating analysis report", and the entire cycle may take several hours or even longer. Such a lag makes the detection result a kind of "ex post facto acceptance" rather than a kind of "process control" tool. For example, when the detection report points out that the curvature of the concrete formwork in a certain area does not meet the standard, the concrete pouring work on site may have already started, missing the best adjustment opportunity. Especially for the concrete formwork shaping pre-tightening force mechanism which needs to be finely adjusted, the on-site workers cannot immediately obtain quantitative feedback on the adjustment effect after adjustment, but have to rely on personal experience.

[0008] Fourthly, it is difficult to realize high-frequency dynamic monitoring. The shape and position of the concrete formwork are not constant, and the concrete formwork will deform under the huge lateral pressure during concrete pouring; construction disturbance may also cause displacement of the concrete formwork. High-frequency comparative monitoring (for example, multiple comparative scans before, during and after pouring) of these dynamic changes has high engineering value. However, due to the above-mentioned problems of data redundancy, complex processing and feedback lag, the cost and time cycle of single detection are relatively long, making it not practical to conduct high-frequency scanning monitoring. SUMMARY

[0009] The purpose of the present application is to provide a concrete formwork three-dimensional laser scanning point cloud data processing method and a concrete formwork detection method and device based on three-dimensional laser scanning, to solve the problem of large amount of interference data in the original point cloud data and the need for manual "cleaning".

[0010] In a first aspect, a method for processing three-dimensional laser scanning point cloud data of a concrete form is provided, comprising: when a three-dimensional laser scanner scans a concrete form to be measured in a set scanning manner at a set measurement position, synchronously receiving each sampling point data collected and transmitted in real time by the three-dimensional laser scanner; for each received sampling point data, extracting position information of the corresponding sampling point in real time and determining whether the position of the sampling point falls within a set concrete form shape and position control key region according to the position information; if the result of the determination is yes, storing the sampling point data as target point data in a target point data buffer area, and if the result of the determination is no, discarding the sampling point data; after the scanning is completed, forming a target point cloud according to all the target point data stored in the target point data buffer area, and obtaining a data processing result based on the target point cloud; wherein the concrete form shape and position control key region is a key region defined by a concrete form two-dimensional view for determining the shape and position control quality of the concrete form to be measured, and a mapping relationship exists between an image coordinate system of the concrete form two-dimensional view and an angle measurement coordinate system of the three-dimensional laser scanner, so that the position information of each sampling point can be uniquely mapped to a pixel coordinate on the concrete form two-dimensional view.

[0011] As an optimization and / or instantiation of the method for processing three-dimensional laser scanning point cloud data of a concrete form according to the first aspect, further, the mapping relationship is set by the following method, which specifically includes: defining the image coordinate system in a concrete form three-dimensional design model corresponding to the concrete form to be measured, and the two-dimensional perspective view when observing the concrete form three-dimensional design model from the perspective center of the coordinate origin of the image coordinate system is the concrete form two-dimensional view; setting a concrete form shape and position control key region in the concrete form two-dimensional view, and calculating the pixel coordinates of the concrete form shape and position control key region in the image coordinate system through a projection algorithm; at the measurement site of the concrete form to be measured, registering the angle measurement coordinate system of the three-dimensional laser scanner with the image coordinate system, so that the three-dimensional laser scanner is placed at the set measurement position.

[0012] As an optimization and / or instantiation of the first aspect of the method for processing three-dimensional laser scanning point cloud data of a concrete formwork, further: the registration specifically includes: defining a global positioning reference in the three-dimensional design model of the concrete formwork as a first global positioning reference, defining a global positioning reference in the measurement site as a second global positioning reference, and unifying the first global positioning reference and the second global positioning reference; determining the relative positional relationship between the image coordinate system and the first global positioning reference, and defining the relative positional relationship between the image coordinate system and the first global positioning reference as a first relative positional relationship; measuring the relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference, and defining the relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference as a second relative positional relationship; adjusting the pose of the three-dimensional laser scanner so that the second relative positional relationship is consistent with the first relative positional relationship.

[0013] As an optimization and / or instantiation of the first aspect of the method for processing three-dimensional laser scanning point cloud data of a concrete formwork, further: the key area of shape and position control of the concrete formwork includes a concrete formwork edge profile, and the concrete formwork thickness can be observed from the concrete formwork edge profile.

[0014] As an optimization and / or instantiation of the first aspect of the method for processing three-dimensional laser scanning point cloud data of a concrete formwork, further: the concrete formwork edge profile is arc-shaped.

[0015] As an optimization and / or instantiation of the first aspect of the method for processing three-dimensional laser scanning point cloud data of a concrete formwork, further: a plurality of concrete formwork shaping pre-tightening force mechanisms are arranged on the to-be-measured concrete formwork along the profile line direction corresponding to the concrete formwork edge profile, and each concrete formwork shaping pre-tightening force mechanism is adjusted by an independent pre-tightening force adjusting device, so that the to-be-measured concrete formwork is deformed to adapt to the shape of the shaped keel and is fixed on the keel.

[0016] As an optimization and / or instantiation of the first aspect of the method for processing three-dimensional laser scanning point cloud data of a concrete formwork, further: the processing result includes comparing the target point cloud with the three-dimensional design model of the concrete formwork corresponding to the to-be-measured concrete formwork, and obtaining a first shape and position deviation analysis result.

[0017] In a second aspect, a concrete formwork detection method based on three-dimensional laser scanning is provided, comprising: before pouring concrete, when a three-dimensional laser scanner is placed on a set measurement position to perform a first scan on a to-be-detected concrete formwork in a set scanning mode, a first data processing result is obtained through a concrete formwork three-dimensional laser scanning point cloud data processing method; during or after pouring concrete, when the three-dimensional laser scanner is re-placed on the same set measurement position to perform a second scan on the to-be-detected concrete formwork in the same set scanning mode, a second data processing result is obtained through the concrete formwork three-dimensional laser scanning point cloud data processing method; the first data processing result and the second data processing result are compared to obtain a second shape and position deviation analysis result; wherein the concrete formwork three-dimensional laser scanning point cloud data processing method is the concrete formwork three-dimensional laser scanning point cloud data processing method of the first aspect.

[0018] As an optimization and / or instantiation of the above-mentioned second aspect of the concrete formwork detection method based on three-dimensional laser scanning, further: before the first scan, a three-dimensional laser scanner movement route is pre-planned, and at least two set measurement positions are distributed on the three-dimensional laser scanner movement route; before pouring concrete, when the first scan is performed on different set measurement positions in sequence according to the three-dimensional laser scanner movement route, a corresponding first data processing result is obtained through the concrete formwork three-dimensional laser scanning point cloud data processing method; during or after pouring concrete, when the second scan is performed on different set measurement positions in sequence according to the three-dimensional laser scanner movement route, a corresponding second data processing result is obtained through the concrete formwork three-dimensional laser scanning point cloud data processing method; each first data processing result and the corresponding second data processing result are compared to obtain a corresponding second shape and position deviation analysis result.

[0019] As an optimization and / or instantiation of the above-mentioned second aspect of the concrete formwork detection method based on three-dimensional laser scanning, further: the to-be-detected concrete formwork is used for pouring an arch-shaped corridor group arranged in a horizontal and vertical staggered manner; and the three-dimensional laser scanner movement route is arranged along an arch-shaped passage of the arch-shaped corridor group.

[0020] In a third aspect, a concrete formwork detection device based on three-dimensional laser scanning is provided, comprising a processor and a memory coupled to each other, and the memory stores a computer program, when the processor executes the computer program, the method of the second aspect based on three-dimensional laser scanning is implemented.

[0021] The concrete formwork three-dimensional laser scanning point cloud data processing method, the concrete formwork detection method based on three-dimensional laser scanning, and the concrete formwork detection device based on three-dimensional laser scanning provided by the application have the following remarkable beneficial effects:

[0022] First, the data is simplified from the data source, and the problems of data redundancy and manual "cleaning" are completely solved. The three-dimensional laser scanning point cloud data processing method provided by the application overturns the traditional working mode of "first full-plate collection, then tedious processing". When scanning is performed on the three-dimensional laser scanner, each sampling point data is judged in real time, and only the points falling within the preset key area of the form and position control of the concrete formwork are stored as target point data in the cache area, and a large number of irrelevant interference data are directly discarded. This real-time filtering mechanism at the data collection source fundamentally avoids the generation of a large amount of redundant data, so that the final target point cloud is pure and small in size, and the subsequent manual or semi-automatic "cleaning" work can be saved, greatly reducing the burden of data transmission and storage, and significantly improving the overall efficiency from scanning to obtaining usable point cloud.

[0023] Second, the rapid feedback of the detection result can be realized, which provides conditions for changing "post-inspection" to "process control". Using the three-dimensional laser scanning point cloud data processing method for concrete formwork provided by the application, since the obtained target point cloud does not need time-consuming and laborious post-processing, the data processing result (for example, the first form and position deviation analysis result obtained by comparing the target point cloud with the three-dimensional design model of the concrete formwork corresponding to the to-be-tested concrete formwork) can be quickly analyzed after scanning is completed.

[0024] Third, high-frequency dynamic deformation monitoring is possible. The three-dimensional laser scanning point cloud data processing method of the application greatly shortens the time consumption of single detection, so that the three-dimensional laser scanning-based concrete formwork detection method including first scanning and second scanning is realized. By comparing the first data processing result with the second data processing result, the second form and position deviation analysis result can be obtained, so as to accurately quantify the deformation of the formwork under the lateral pressure of concrete. This high-frequency dynamic monitoring capability provides direct data support for early warning and control of formwork deformation in the pouring process and prevention of formwork expansion and other major quality accidents.

[0025] The application will be further described below in conjunction with the drawings and specific embodiments. Additional aspects and advantages of the application will be partially given in the following description, partially become apparent from the following description, or be understood by practice. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings constituting a part of this specification serve to aid in the understanding of the application, and the content provided in the drawings and its related description in the specification can be used to explain the application, but do not constitute an improper limitation on the application.

[0027] Figure 1 A three-dimensional view of an arch-shaped corridor group for a three-dimensional laser scanning-based concrete formwork detection method of an embodiment of the application.

[0028] Figure 2 For Figure 1 Three-dimensional view of the arched corridor group from another angle.

[0029] Figure 3 For Figure 1 Position relationship between the prefabricated reinforced concrete frame and the later-built outer body of the corridor.

[0030] Figure 4 For Figure 3 Arrangement diagram of the concrete formwork corresponding to the arched passageway in the outer body of the corridor.

[0031] Figure 5 For Figure 4 Partial view (enlarged shaped keel and concrete formwork shaping pre-tightening force mechanism) in

[0032] Figure 6 For Figure 1 Overall diagram of the overall concrete formwork system of the large public building in which the arched corridor group is located.

[0033] Figure 7 Point cloud diagram formed by the original point cloud data obtained by scanning a certain concrete formwork (for pouring the corresponding arched passageway) by a three-dimensional laser scanner.

[0034] Figure 8 In a concrete formwork three-dimensional laser scanning point cloud data processing method of an embodiment of the application, a schematic diagram of defining an image coordinate system in a concrete formwork three-dimensional design model.

[0035] Figure 9 In a concrete formwork three-dimensional laser scanning point cloud data processing method of an embodiment of the application, a schematic diagram of setting a concrete formwork shape and position control key area in a two-dimensional view of the concrete formwork.

[0036] Figure 10 In a concrete formwork three-dimensional laser scanning point cloud data processing method of an embodiment of the application, a schematic diagram of obtaining a first data processing result by the method when scanning for the first time.

[0037] Figure 11 Data processing result (target point cloud diagram formed by target point cloud) obtained by a concrete formwork three-dimensional laser scanning point cloud data processing method of an embodiment of the application.

[0038] Figure 12 In a concrete formwork three-dimensional laser scanning point cloud data processing method of an embodiment of the application, a schematic diagram of a planned three-dimensional laser scanner movement route.

[0039] In the figure, the following are marked: 100 - arched corridor; 200 - reinforced concrete frame; 300 - main body outside the corridor; 400 - concrete formwork; 401 - shaped keel; 402 - concrete formwork shaping pre-tightening force mechanism; 403 - pre-tightening force adjusting device; 500 - operation interface; 600 - three-dimensional design model of concrete formwork; 601 - image coordinate system; 700 - two-dimensional view of concrete formwork; 701 - key area of shape and position control of concrete formwork; 702 - edge profile of concrete formwork; A - first measuring station; B - second measuring station; C - third measuring station. DETAILED DESCRIPTION

[0040] The present application will be described in detail below with reference to the drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is described in detail with reference to the drawings, it is important to understand that the present application is not limited in any way by the drawings and the application can be practiced with other structures, systems, materials, and methods.

[0041] The technical solutions and technical features provided in each part including the following description can be combined with each other without conflict. In addition, in possible cases, these technical solutions, technical features and related combinations can be given a specific technical subject and protected by a related patent.

[0042] The embodiments of the present application involved in the following description are usually only a part of the embodiments and not all the embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of patent protection.

[0043] The terms "include", "contain", "have" and any variations thereof in the present description and the corresponding claims and related parts are intended to cover non-exclusive inclusion. Other related terms and units can be reasonably interpreted based on the related content provided in the present description.

[0044] Please refer to Figure 1 and Figure 2 . Figure 1 A three-dimensional view of an arched corridor group to which a concrete formwork detection method based on three-dimensional laser scanning is directed; Figure 2 A three-dimensional view of the arched corridor group shown in Figure 1 The two figures together show an arched corridor group required to be constructed inside a large public building, which is composed of a large number of large arched corridors 100 arranged in a horizontal and vertical staggered manner, has a complex structure, and requires cast-in-place forming of fair-faced concrete, directly taking the natural texture of fair-faced concrete as the final architectural interior and exterior finish.

[0045] Please refer to Figure 3 . Figure 3 A three-dimensional view of the arched corridor group shown in Figure 1The figure shows the position relationship between the first built reinforced concrete frame and the later built corridor exterior body. The figure reveals the construction sequence of the arched corridor group: first complete the construction of the reinforced concrete frame 200 as the load-bearing support structure, and then proceed to the fair-faced concrete pouring of the corridor exterior body 300. The specific technical problem to be solved by the embodiment of the present invention is the shape and position control of the concrete formwork used in the pouring construction of the corridor exterior body 300.

[0046] Please refer to Figure 4 . Figure 4 To Figure 3 the arched passageway in the corridor exterior body shown in FIG. 1. In order to achieve high-precision curved surface modeling of the arched passageway, a highly customized concrete formwork 400 is used. The large face of the concrete formwork 400 needs to be curved into an accurate arc to meet the stringent requirements of fair-faced concrete on surface quality.

[0047] Please refer to Figure 5 . Figure 5 To Figure 4 the local view (enlarged shaped keel and concrete formwork shaping pre-tightening force mechanism) in FIG. 1. The figure shows the details of the shaped keel and concrete formwork shaping pre-tightening force mechanism in an enlarged manner. The figure clearly shows the key components of the concrete formwork 400: the large face of the concrete formwork 400 needs to be curved into an accurate arc, and its back is supported and profiled by the shaped keel 401. In the direction of the curved profile line of the concrete formwork 400 (i.e. the profile line corresponding to the edge profile of the concrete formwork), a plurality of concrete formwork shaping pre-tightening force mechanisms 402 are arranged at intervals. In this embodiment, the concrete formwork shaping pre-tightening force mechanism 402 is specifically a pre-stressed screw. Each concrete formwork shaping pre-tightening force mechanism 402 is adjusted by an independent pre-tightening force adjusting device 403. In this embodiment, the pre-tightening force adjusting device 403 is specifically a locking nut. The on-site workers adjust the pre-tightening force adjusting device 403 to apply accurate and dispersed forces to the concrete formwork 400, so that the measured concrete formwork adapts to the shape of the shaped keel 401 through deformation and is fixed on the shaped keel 401, so that the large face of the concrete formwork can perfectly adapt to the preset profile of the shaped keel 401.

[0048] From Figure 5As can be seen more clearly, the shaping keel 401 employs longitudinally extending stiffening plates, which are bent into a preset arc to define the target bending shape of the concrete formwork 400. Between the large surface of the concrete formwork 400 and the stiffening plates of the shaping keel 401, multiple transverse support plates are spaced along the bending contour of the concrete formwork 400. These transverse support plates enhance the overall support of the shaping keel 401 for the large surface of the concrete formwork 400. Multiple concrete formwork shaping prestressing mechanisms 402 (prestressed screws) pass through the shaping keel 401 in an array, forming a multi-point constraint system for the concrete formwork 400. One end of each prestressed screw passes through the large surface of the concrete formwork 400 and is locked in place with a nut, while the other end passes through a crossbar (used to distribute the tension of the prestressed screw) arranged on the surface of the shaping keel 401 and is fixed with a locking nut. This double-end locking structure allows the concrete formwork shaping pre-tightening mechanism 402 to apply a controllable tension force to the concrete formwork 400 when the worker rotates the pre-tightening force adjustment device 403. This forces the large surface of the concrete formwork 400 to gradually conform to the preset arc contour of the shaping keel 401, thereby achieving precise shaping of the concrete formwork. In actual construction sites, the shaping keel 401 needs to be supported by a scaffolding system.

[0049] Please see Figure 6 . Figure 6 for Figure 1 This is an overview diagram of the overall concrete formwork system of the large public building containing the arched corridor complex. As can be seen from the diagram, the overall concrete formwork system is massive and structurally complex, posing a significant challenge to subsequent 3D laser scanning inspection.

[0050] Please see Figure 7 . Figure 7 This is a point cloud image generated from the original point cloud data obtained after scanning a concrete formwork (used for pouring the corresponding arched channel) using a 3D laser scanner. The image clearly shows that when using traditional scanning methods, in addition to the large area of ​​the concrete formwork that actually needs analysis, the field of view is filled with a massive amount of point cloud data related to supporting scaffolding, as well as the point cloud data of the shaping joists and pre-tensioning mechanisms of the concrete formwork attached to its back. These point cloud data are collectively referred to as interference data. This interference data completely overwhelms the effective data, resulting in most of the original point cloud data being interference data that is not very relevant to shape and position control, making subsequent processing extremely difficult.

[0051] To address the aforementioned problems, this invention provides a method for processing three-dimensional laser scanning point cloud data of concrete formwork. The following is a detailed explanation... Figure 8 to Figure 11 This method will be explained in detail. The core of this method lies in real-time filtering at the source of data acquisition to avoid interfering with data storage and transmission.

[0052] Example 1.

[0053] The embodiment provides a basic implementation of a three-dimensional laser scanning point cloud data processing method for a concrete formwork, and the method comprises the following steps.

[0054] In step S1, when the three-dimensional laser scanner scans the to-be-measured concrete formwork at a set measurement position in a set scanning mode, each sampling point data collected by the three-dimensional laser scanner and transmitted in real time is synchronously received.

[0055] In this step, the three-dimensional laser scanner scans the to-be-measured concrete formwork according to a pre-set scanning mode (for example, parameters such as set resolution and scanning range). During the scanning process, the three-dimensional laser scanner collects the data of each sampling point in real time, and transmits the sampling point data in real time. The receiving end (a computer or a special data processing device connected with the three-dimensional laser scanner) synchronously receives the sampling point data.

[0056] Each sampling point data usually contains the position information (for example, angle coordinates and distance information in the angle measurement coordinate system of the three-dimensional laser scanner) of the sampling point and other possible information (for example, reflection intensity).

[0057] At present, mainstream three-dimensional laser scanners (for example, FARO Focus series) all have the function of real-time data stream output. These three-dimensional laser scanners usually provide the following several real-time data output modes.

[0058] Most three-dimensional laser scanners are equipped with an Ethernet interface or a USB interface, and can be directly connected with a computer through a network cable or a USB data line. During the scanning process, the three-dimensional laser scanner transmits the sampling point data in the form of a data stream in real time through the interface. The data transmission protocol usually adopts a TCP / IP protocol or a special communication protocol provided by a device manufacturer. The receiving end computer continuously receives the sampling point data stream transmitted by the three-dimensional laser scanner by listening to a specified network port or a USB port.

[0059] In addition, some three-dimensional laser scanners also support the connection with a computer through a wireless mode such as WiFi or Bluetooth and the real-time transmission of data. This mode is particularly useful in the case where field wiring is inconvenient. The wireless transmission also adopts a TCP / IP protocol, and the receiving end computer receives data by being connected to the same wireless network as the three-dimensional laser scanner and listening to the IP address and port specified by the device.

[0060] The sampling point data output by the 3D laser scanner in real time is usually in binary format or text format (such as ASCII code). Each sampling point data often contains the horizontal angle, vertical angle, distance value of the sampling point, and sometimes contains additional information such as reflection intensity value, RGB color value. The structure of the data packet of each sampling point data is defined by the communication protocol of the device manufacturer, usually including data header (identifying data type and length) and data body (containing actual measurement value).

[0061] The receiving end usually uses a portable notebook computer or an industrial tablet computer for use on the construction site. The receiving end needs to be equipped with a corresponding communication interface (Ethernet port, USB port or WiFi module) to establish a connection with the 3D laser scanner.

[0062] In this embodiment, a specially written data receiving and processing software needs to be run on the receiving end. The software uses a multi-thread architecture, mainly including a data receiving thread, a data processing thread and a user interface thread. The data receiving thread is responsible for continuously listening to the communication interface and receiving the sampling point data; the data processing thread is responsible for real-time judgment and filtering of the received sampling point data; the user interface thread is responsible for displaying the scanning progress, target point cloud and analysis results.

[0063] Before starting the scan, first start the data receiving thread on the receiving end. The data receiving thread will try to establish a communication connection with the 3D laser scanner. After the connection is established, the data receiving thread enters the listening state and continuously receives the data stream sent by the 3D laser scanner through the communication interface. The data receiving thread reads the data buffer of the network port or USB port through a loop to obtain each sampling point data sent by the 3D laser scanner in real time.

[0064] The data receiving thread uses the socket programming interface to establish a communication connection with the 3D laser scanner. For TCP / IP network connection, use TCP socket; for USB connection, use the USB communication library provided by the device manufacturer or the standard serial communication interface. The data receiving thread enters an infinite loop, and in the loop, it continuously calls the receive function (such as recv() or read()) to read data from the communication interface. Each time the data read may contain one or more complete sampling point data packets, or it may be part of a data packet. Therefore, the data receiving thread needs to implement the packet segmentation and recombination function, and according to the data packet format defined by the device communication protocol, correctly segment the received byte stream into one complete sampling point data packet.

[0065] For each complete sample point data packet, the data receiving thread parses out the position information (horizontal angle, vertical angle, distance value) and other additional information (such as reflection intensity) of the sample point according to the format definition of the device communication protocol. The parsing usually involves byte sequence conversion (big-endian or little-endian) and data type conversion (such as converting a byte array to a floating-point number). After parsing, the sample point data is encapsulated into a data structure used internally by the program (such as a structure or object containing fields such as angle, distance, etc.), and is placed in the data receiving queue for use by the data processing thread.

[0066] Some three-dimensional laser scanner manufacturers provide a software development kit (SDK) that encapsulates the underlying details of device communication, data reception, and parsing, and provides a higher-level application programming interface (API). In this case, the API functions provided by the SDK can be directly called to establish a connection, receive data, and parse data, without the need to implement the underlying communication and data packet parsing logic.

[0067] In step S2, for each received sample point data, the position information of the corresponding sample point is extracted in real time, and it is determined whether the position of the sample point falls within the set form and position control key area of the concrete formwork.

[0068] In this step, for each received sample point data, the position information of the sample point is first extracted. Then, it is determined whether the position of the sample point falls within the pre-set form and position control key area of the concrete formwork.

[0069] The form and position control key area of the concrete formwork is defined by a two-dimensional view of the concrete formwork to determine the focus area of the form and position control quality of the concrete formwork to be measured. There is a mapping relationship between the image coordinate system of the two-dimensional view of the concrete formwork and the angle measurement coordinate system of the three-dimensional laser scanner, so that the position information of each sample point can be uniquely mapped to a pixel coordinate on the two-dimensional view of the concrete formwork.

[0070] Through this mapping relationship, the position information of the sample point in the angle measurement coordinate system of the three-dimensional laser scanner can be converted to the pixel coordinate of the sample point on the two-dimensional view of the concrete formwork, and it is further determined whether the pixel coordinate falls within the pre-set form and position control key area of the concrete formwork in the two-dimensional view of the concrete formwork.

[0071] In this embodiment, after the data processing thread obtains the sample point data from the data receiving queue, the following processing is performed for each sample point data:

[0072] Extract position information: Extract the position information of the sampling point from the sampling point data structure, i.e. the horizontal angle θ, the vertical angle φ and the distance value r. These values constitute the coordinate representation of the sampling point in the angle measurement coordinate system of the three-dimensional laser scanner (also known as the spherical coordinate system or polar coordinate system).

[0073] Coordinate mapping: According to the pre-established mapping relationship, convert the coordinates (θ, φ, r) of the sampling point in the angle measurement coordinate system of the three-dimensional laser scanner into the pixel coordinates (u, v) of the sampling point on the two-dimensional view of the formwork.

[0074] Since the mapping relationship between the image coordinate system and the angle measurement coordinate system of the three-dimensional laser scanner has been established, the mapping relationship essentially defines the perspective projection transformation from the three-dimensional space point to the two-dimensional image plane. The parameters of the mapping relationship (including the rotation matrix R of the image coordinate system relative to the angle measurement coordinate system and the translation vector T, the focal length f of the image plane, the principal point coordinates and other internal parameters) have been determined and stored in the program.

[0075] For the spherical coordinates (θ, φ, r) of the sampling point, first convert them to Cartesian coordinates (X, Y, Z) in the angle measurement coordinate system of the three-dimensional laser scanner: X = r·cos(φ)·cos(θ); Y = r·cos(φ)·sin(θ); Z = r·sin(φ).

[0076] Then, apply the rotation matrix R and the translation vector T to convert the point from the angle measurement coordinate system to the image coordinate system: [X', Y', Z'] T =R·[X,Y,Z] T +T.

[0077] Finally, apply the perspective projection formula to project the three-dimensional point (X', Y', Z') onto the two-dimensional image plane to obtain the pixel coordinates: u = f·X' / Z' + u0; v = f·Y' / Z' + v0, where (u0, v0) are the pixel coordinates of the image principal point and f is the focal length.

[0078] The above calculation is realized by matrix operation in the program, and the use of efficient linear algebra library (such as Eigen, OpenCV, etc.) can quickly complete the calculation.

[0079] After obtaining the pixel coordinates (u, v) of the sampling point on the two-dimensional view of the formwork, it is determined whether the pixel coordinates fall within the pre-set key area of the formwork shape and position control.

[0080] The key region of the formwork shape position control is stored in the program in the form of a mask image. The mask image is a binary image with the same size as the two-dimensional view of the formwork, in which the pixel value of the key region of the formwork shape position control is 1 (or 255), and the pixel value of the region not belonging to the key region is 0. The mask image is generated according to the key region of the formwork shape position control set in the two-dimensional view of the formwork before scanning and is loaded into the program.

[0081] The judgment process is very simple: read the pixel value of the coordinate (u, v) in the mask image. If the pixel value is 1 (or 255), the judgment result is yes, that is, the sampling point falls into the key region of the formwork shape position control; if the pixel value is 0, the judgment result is no, that is, the sampling point does not fall into the key region.

[0082] In order to improve the judgment efficiency, the program first checks whether the pixel coordinate (u, v) is within the image range (that is, 0≤u

[0083] Step S3: If the result of the judgment is yes, the sampling point data is stored as target point data in the target point data buffer area; if the result of the judgment is no, the sampling point data is discarded.

[0084] In this step, according to the judgment result of step S2, the sampling point data is selectively processed. If the judgment result is yes, that is, the position of the sampling point falls into the key region of the formwork shape position control, the sampling point data is considered to be valid and needs to be retained, and is stored as target point data in the target point data buffer area. If the judgment result is no, that is, the position of the sampling point does not fall into the key region of the formwork shape position control, the sampling point data is considered to be interference data and is directly discarded without storage.

[0085] Through this real-time selective storage mechanism, a large amount of interference data can be filtered out at the source of data acquisition, and only the truly useful target point data is retained, thereby greatly reducing the data volume.

[0086] In this embodiment, the target point data buffer area is implemented as a dynamically growing data structure, such as a dynamic array (std::vector in C++) or a linked list in the program. The data structure stores all the sampling point data judged to fall into the key region of the formwork shape position control.

[0087] When the result is yes, the data processing thread adds the sampling point data to the end of the target point data buffer. The adding operation usually includes: allocating storage space (extending its capacity if the current buffer is full), copying various fields (coordinates, reflection intensity, etc.) of the sampling point data to the newly allocated space. When the result is no, the data processing thread does not perform any storage operation, and the temporary memory space occupied by the sampling point data is released or recycled into the memory pool after processing, thereby realizing the abandonment of data.

[0088] Step S4, after the scanning is completed, a target point cloud is formed according to all the target point data stored in the target point data buffer, and a data processing result is obtained based on the target point cloud.

[0089] In this step, when the three-dimensional laser scanner completes the entire scanning process, the target point data buffer has accumulated all the sampling point data that is judged to fall into the concrete formwork shape and position control key area during the scanning process. According to all the target point data, a target point cloud is formed. Based on the target point cloud, a data processing result can be obtained.

[0090] Ideally, the target point cloud is a substantially pure point cloud that mainly contains data of the concrete formwork shape and position control key area, and does not substantially contain point cloud data of interfering structures such as scaffolds, shape guide rails, and concrete formwork shaping and pre-tightening mechanisms.

[0091] Figure 11 For a concrete formwork three-dimensional laser scanning point cloud data processing method according to an embodiment of the present application, a data processing result (a target point cloud diagram formed by a target point cloud) is obtained. As shown in Figure 11 The target point cloud diagram clearly presents the outline of the concrete formwork, which is in an overall arc structure, and the point cloud data is mainly concentrated on the surface of the concrete formwork and does not contain point cloud data of interfering structures such as scaffolds, shape guide rails, and concrete formwork shaping and pre-tightening mechanisms.

[0092] In this embodiment, the judgment basis for the end of scanning is usually that the three-dimensional laser scanner sends a scanning completion signal (through a specific data packet or device state flag), or the interruption of the received sampling point data stream exceeds a preset time threshold.

[0093] When the end of scanning is detected, the data receiving thread and the data processing thread stop working, and the target point cloud is generated. The generation process of the target point cloud includes: traversing all the target point data in the target point data buffer area, and extracting the coordinate information of each point. The coordinates can be kept in spherical coordinate form (θ, φ, r), or can be converted into Cartesian coordinates (X, Y, Z). Usually, for the convenience of subsequent analysis and display, the Cartesian coordinates are uniformly converted. A point cloud object is constructed using the data structure provided by the point cloud processing library (such as PCL -Point Cloud Library). The generated target point cloud is saved as a standard point cloud file format, such as PCD (Point Cloud Data), PLY (Polygon File Format) or LAS (LASer file format) and the like. These files can be read and further analyzed by other point cloud processing software (such as CloudCompare, Autodesk ReCap, etc.).

[0094] Based on the target point cloud, the above-mentioned data receiving and processing software can generate various forms of data processing results. For example, the target point cloud is displayed in the user interface using a three-dimensional graphics rendering engine (such as OpenGL, VTK, etc.). The operator can rotate the viewing angle, zoom in and out of the view by dragging the mouse, observe the target point cloud from different angles, and intuitively evaluate the shape and position of the concrete formwork. When the point cloud is displayed, color mapping can be performed according to the height, distance or reflectivity of the points, etc. to enhance the visual effect.

[0095] In addition, the target point cloud can also be compared with the three-dimensional design model of the concrete formwork corresponding to the measured concrete formwork to obtain a first shape and position deviation analysis result. The specific implementation manner is as follows: first, load the three-dimensional design model of the concrete formwork, which is usually a three-dimensional model file (such as STEP, IGES format) exported by CAD software or a mesh model (such as STL format) composed of triangular facets. Then, for each point in the target point cloud, the nearest distance from the point to the surface of the design model is calculated, and the distance is the shape and position deviation value of the point. The algorithm for calculating the nearest distance usually uses a spatial index structure such as KD tree (K-Dimensional Tree) to accelerate the search. After obtaining the deviation values of all points, statistical analysis is performed to calculate statistical quantities such as maximum deviation, average deviation, root mean square deviation, and a deviation distribution histogram is generated. At the same time, the deviation values can be mapped to colors, and displayed in the form of a color spectrum on the point cloud.

[0096] Embodiment two.

[0097] On the basis of embodiment one, the embodiment further illustrates the setting mode of the mapping relationship between the image coordinate system of the concrete form two-dimensional view and the angle measurement coordinate system of the three-dimensional laser scanner. The mapping relationship is set by the following mode, which specifically includes the following steps:

[0098] Please refer to Figure 8 . Figure 8 For a concrete form three-dimensional laser scanning point cloud data processing method of an embodiment of the application, a schematic diagram of defining an image coordinate system in a concrete form three-dimensional design model is shown.

[0099] Step M1: defining the image coordinate system 601 in the concrete form three-dimensional design model 600 corresponding to the concrete form to be measured. The two-dimensional perspective view of the concrete form three-dimensional design model 600 observed from the perspective center of the coordinate origin of the image coordinate system 601 is the concrete form two-dimensional view 700.

[0100] In this step, first, the concrete form three-dimensional design model 600 corresponding to the concrete form to be measured is obtained. The three-dimensional design model is usually completed in the design stage and contains information such as the geometric shape and size of the concrete form.

[0101] Then, in the concrete form three-dimensional design model 600, a virtual image coordinate system 601 is defined according to the expected scanning station (i.e., the expected placement position of the three-dimensional laser scanner). The coordinate origin of the image coordinate system 601 corresponds to the position where the scanning center of the three-dimensional laser scanner is expected to be located.

[0102] Next, a two-dimensional perspective view is generated by observing the concrete form three-dimensional design model 600 with the coordinate origin of the image coordinate system 601 as the perspective center. The two-dimensional perspective view simulates the view observed from the perspective of the three-dimensional laser scanner when observing the concrete form to be measured, which is the concrete form two-dimensional view 700.

[0103] In this embodiment, step M1 is specifically implemented on a computer through a three-dimensional modeling software. An operator defines the image coordinate system 601 in the concrete form three-dimensional design model 600 through the operation interface 500 of the three-dimensional modeling software displayed on the computer screen. Generally, the three-dimensional modeling software supports the operator to view and adjust the concrete form two-dimensional view 700 based on the defined image coordinate system 601 displayed on the computer screen. After the image coordinate system 601 is defined, the relative position relationship between the global positioning reference of the concrete form three-dimensional design model 600 and the image coordinate system 601 can be obtained.

[0104] Please refer to Figure 9 . Figure 9In a three-dimensional laser scanning point cloud data processing method for a concrete formwork according to an embodiment of the present application, a schematic diagram of a key area for shape and position control of the concrete formwork is set in a two-dimensional view of the concrete formwork.

[0105] Step M2: A key area for shape and position control of the concrete formwork is set in the two-dimensional view 700 of the concrete formwork, and pixel coordinates of the key area for shape and position control of the concrete formwork in the image coordinate system 601 are calculated by a projection algorithm.

[0106] In this step, a key area for shape and position control of the concrete formwork 701 is set in the generated two-dimensional view 700 of the concrete formwork by a technician according to detection requirements and shape and position control requirements. The key area for shape and position control of the concrete formwork 701 is a key area for determining the shape and position control quality of the concrete formwork to be detected.

[0107] In a specific embodiment, the key area for shape and position control of the concrete formwork 701 includes a concrete formwork edge profile 702, from which the thickness of the concrete formwork can be observed. The concrete formwork edge profile is a key position for checking the bending accuracy of the concrete formwork. By observing the point cloud at this position, the shape and position of the concrete formwork can be accurately evaluated to determine whether they meet the design requirements.

[0108] In a more specific embodiment, the concrete formwork edge profile 702 is arc-shaped. This is consistent with the application scenario of the arched corridor targeted by the present application, which requires the concrete formwork to be bent into an accurate arc.

[0109] After the setting is completed, the pixel coordinate range of the key area for shape and position control of the concrete formwork 701 in the image coordinate system 601 is calculated by a projection algorithm. Specifically, the key area for shape and position control of the concrete formwork 701 is defined as a region in the two-dimensional view 700 of the concrete formwork in units of pixels, and the coordinates of each pixel in the region in the image coordinate system 601 can be determined by a projection algorithm.

[0110] In this embodiment, step M2 is also completed in operation interface 500. The technician can interactively delineate the formwork shape control key region 701. Conventional three-dimensional modeling software generally has built-in view selection and region labeling functions, which can directly support such operations. Taking the commonly used three-dimensional modeling software Creo Parametric as an example, the technician first opens the formwork three-dimensional design model 600, and generates the formwork two-dimensional view 700 based on the defined image coordinate system 601. Then, the “sketch” function is entered, and spline curves, circular arcs, etc. are used to delineate along the formwork edge contour 702 to circumscribe the formwork shape control key region 701. In order to obtain the pixel coordinates of the formwork shape control key region 701 in the image coordinate system 601, a special plug-in based on Creo Toolkit (a secondary development toolkit officially provided by Creo Parametric) is developed. The plug-in automatically reads the three-dimensional coordinates of the vertices and curve control points of the sketched geometry (formwork shape control key region 701) in the image coordinate system 601 by calling API functions, and then converts them into pixel coordinates on the formwork two-dimensional view 700 through perspective projection formula, and finally exports the pixel coordinates in bulk as a data file. The data file exported here is the pixel coordinate data used to generate the mask image, which is used to determine whether the sampling point falls within the formwork shape control key region 701 in real time in the aforementioned step S2.

[0111] Step M3: In the measurement site of the formwork to be measured, the angle measurement coordinate system of the three-dimensional laser scanner is registered with the image coordinate system 601, so that the three-dimensional laser scanner is placed at the set measurement position.

[0112] In this step, in the actual measurement site, the three-dimensional laser scanner needs to be accurately placed at the actual position corresponding to the position expected when the image coordinate system 601 is defined in the formwork three-dimensional design model. This is achieved by registering the angle measurement coordinate system of the three-dimensional laser scanner with the image coordinate system 601.

[0113] After registration, an accurate mapping relationship is established between the angle measurement coordinate system of the three-dimensional laser scanner and the image coordinate system 601. At this time, the position information of each sampling point collected by the three-dimensional laser scanner (represented in the angle measurement coordinate system of the three-dimensional laser scanner) can be uniquely converted into the pixel coordinates of the sampling point on the formwork two-dimensional view 700 through the mapping relationship, and then it can be determined whether the sampling point falls within the formwork shape control key region 701.

[0114] Example Three.

[0115] On the basis of Embodiment Two, this embodiment further illustrates the specific implementation of the registration in Step M3. The registration specifically comprises the following steps:

[0116] Step C1 : defining the global positioning reference in the three-dimensional design model 600 of the concrete formwork as a first global positioning reference, defining the global positioning reference in the measurement site as a second global positioning reference, and unifying the first global positioning reference and the second global positioning reference.

[0117] In this step, two global positioning references are first defined. The first global positioning reference is a global reference coordinate system defined in the three-dimensional design model 600 of the concrete formwork, which is usually determined in the design stage and used to uniformly describe the positional relationship of various parts of the entire building structure. The second global positioning reference is a global reference coordinate system established in the actual measurement site, which is used to uniformly describe the positional relationship of various measurement objects and measurement equipment in the site.

[0118] In order to make the coordinate system in the three-dimensional design model of the concrete formwork correspond to the coordinate system in the measurement site, the first global positioning reference needs to be unified with the second global positioning reference. This is usually achieved by setting up corresponding control points in the site as the first global positioning reference and measuring the coordinates of these control points in the second global positioning reference, thereby establishing the conversion relationship between the first global positioning reference and the second global positioning reference.

[0119] Step C2: determining the relative positional relationship between the image coordinate system and the first global positioning reference, and defining the relative positional relationship between the image coordinate system and the first global positioning reference as a first relative positional relationship.

[0120] In this step, based on the image coordinate system 601 defined in the three-dimensional design model of the concrete formwork and the first global positioning reference, the relative positional relationship between the image coordinate system 601 and the first global positioning reference is determined. This relative positional relationship usually includes translation and rotation, which can be represented by a transformation matrix. This relative positional relationship is defined as the first relative positional relationship.

[0121] Since the image coordinate system 601 and the first global positioning reference are both defined in the three-dimensional design model of the concrete formwork, the relative positional relationship between them can be directly calculated through the coordinates in the design model.

[0122] Step C3: measuring the relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference, and defining the relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference as a second relative positional relationship.

[0123] In this step, the relative position relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference is determined by measurement means (e.g. total station measurement, GNSS measurement, etc.) at the measurement site. The relative position relationship also includes both translation and rotation. The relative position relationship is defined as the second relative position relationship.

[0124] Step C4: adjusting the pose of the three-dimensional laser scanner so that the second relative position relationship is consistent with the first relative position relationship.

[0125] In this step, the second relative position relationship is made consistent with the first relative position relationship by adjusting the position and attitude of the three-dimensional laser scanner at the measurement site. When the two are consistent, it means that the angle measurement coordinate system of the three-dimensional laser scanner and the image coordinate system 601 are registered, and the three-dimensional laser scanner is accurately placed at the set measurement position.

[0126] After registration is completed, the position information of the sampling points collected by the three-dimensional laser scanner in its angle measurement coordinate system can be converted into the coordinates of the sampling points in the image coordinate system 601 through the known coordinate transformation relationship, and then mapped to the pixel coordinates on the concrete formwork two-dimensional view 700, thereby realizing the judgment of whether the sampling points fall into the concrete formwork shape and position control key area 701.

[0127] Based on the above efficient concrete formwork three-dimensional laser scanning point cloud data processing method, the application further provides a concrete formwork detection method based on three-dimensional laser scanning. This method can realize the monitoring of the dynamic deformation of the concrete formwork during the pouring process.

[0128] The embodiment provides a basic implementation of a concrete formwork detection method based on three-dimensional laser scanning, which comprises the following steps:

[0129] Step D1: Before pouring concrete, when the three-dimensional laser scanner is placed at the set measurement position to perform the first scanning on the to-be-measured concrete formwork in the set scanning mode, the first data processing result is obtained through the concrete formwork three-dimensional laser scanning point cloud data processing method.

[0130] In this step, before pouring concrete, the three-dimensional laser scanner is placed at the set measurement position to perform the first scanning on the to-be-measured concrete formwork in the set scanning mode. In the scanning process, the concrete formwork three-dimensional laser scanning point cloud data processing method of the above embodiment is used for real-time point cloud data processing to obtain the first data processing result.

[0131] The first data processing result can include the target point cloud obtained by the first scanning, and a first shape and position deviation analysis result obtained based on the target point cloud (i.e., a deviation analysis result obtained by comparing the target point cloud obtained by the first scanning with the three-dimensional design model of the concrete formwork). The first data processing result reflects the shape and position state of the concrete formwork before pouring.

[0132] Step D2: When the three-dimensional laser scanner is repositioned at the same set measurement position and scans the to-be-tested concrete formwork in the same set scanning manner for the second time during or after pouring, a second data processing result is obtained by the concrete formwork three-dimensional laser scanning point cloud data processing method.

[0133] In this step, the three-dimensional laser scanner is repositioned at the same set measurement position as in the first scanning and scans the to-be-tested concrete formwork in the same set scanning manner during or after pouring. Real-time point cloud data processing is performed by the above-mentioned concrete formwork three-dimensional laser scanning point cloud data processing method to obtain a second data processing result.

[0134] The second data processing result can include the target point cloud obtained by the second scanning, and a shape and position deviation analysis result obtained based on the target point cloud (i.e., a deviation analysis result obtained by comparing the target point cloud obtained by the second scanning with the three-dimensional design model of the concrete formwork). The second data processing result reflects the shape and position state of the concrete formwork during or after pouring.

[0135] Step D3: Comparing the first data processing result with the second data processing result to obtain a second shape and position deviation analysis result.

[0136] In this step, the first data processing result is compared with the second data processing result. Specifically, the target point cloud obtained by the first scanning can be compared with the target point cloud obtained by the second scanning in a point-to-point manner to calculate the displacement of each corresponding point between the two scans; or the first shape and position deviation analysis result in the first data processing result can be compared with the shape and position deviation analysis result in the second data processing result to analyze the change in the deviation value.

[0137] Through such comparison, a second shape and position deviation analysis result is obtained. The second shape and position deviation analysis result reflects the shape and position change of the concrete formwork before and after pouring, and can accurately quantify the deformation of the formwork under the lateral pressure of the concrete. This provides direct data support for early warning and control of formwork deformation during pouring and prevention of major quality accidents such as formwork expansion.

[0138] Further, a three-dimensional laser scanner movement route is planned in advance before the first scanning, and at least two set measurement positions are distributed on the three-dimensional laser scanner movement route.

[0139] Please refer to Figure 12 . Figure 12 In one embodiment of the invention, a schematic diagram of a planned moving route of a three-dimensional laser scanner is shown in FIG. 1. As shown in FIG. 1, a moving route of a three-dimensional laser scanner is planned in advance. The moving route is provided with a plurality of set measurement positions, and a first measurement station A, a second measurement station B, and a third measurement station C are shown in the figure, but more measurement stations can be provided according to actual needs. Figure 12

[0140] Before pouring concrete, the first scanning is performed at different set measurement positions according to the planned moving route of the three-dimensional laser scanner, and a corresponding first data processing result is obtained by the three-dimensional laser scanning point cloud data processing method for a formwork.

[0141] In this step, before pouring concrete, an operator carries a three-dimensional laser scanner and moves along the planned moving route of the three-dimensional laser scanner. When reaching each set measurement position (for example, the first measurement station A, the second measurement station B, and the third measurement station C), the three-dimensional laser scanner is placed at the set measurement position, and the first scanning is performed on the to-be-measured formwork in a predetermined set scanning mode. The first data processing result corresponding to the measurement station is obtained by the three-dimensional laser scanning point cloud data processing method.

[0142] In this way, after completing the scanning of the entire moving route, each set measurement position corresponds to a first data processing result, and these results collectively reflect the shape and position state of the to-be-measured formwork before pouring concrete.

[0143] When pouring concrete or after pouring concrete, the second scanning is performed at different set measurement positions according to the planned moving route of the three-dimensional laser scanner, and a corresponding second data processing result is obtained by the three-dimensional laser scanning point cloud data processing method for a formwork.

[0144] In this step, after pouring concrete, the operator again carries the three-dimensional laser scanner and moves along the same moving route of the three-dimensional laser scanner. When reaching each set measurement position, the three-dimensional laser scanner is placed at the set measurement position again (the same position as the first scanning), and the second scanning is performed on the to-be-measured formwork in the same set scanning mode. The second data processing result corresponding to the measurement station is obtained by the three-dimensional laser scanning point cloud data processing method.

[0145] In this way, after completing the scanning of the entire moving route, each set measurement position corresponds to a second data processing result, and these results collectively reflect the shape and position state of the to-be-measured formwork when pouring concrete or after pouring concrete.

[0146] ​The first data processing result and the corresponding second data processing result are compared respectively to obtain a corresponding second geometric and position deviation analysis result.

[0147] In this step, for each set measurement position, the first data processing result obtained by the station in the first scanning is compared with the second data processing result obtained by the station in the second scanning to obtain the second geometric and position deviation analysis result corresponding to the station.

[0148] In this way, each set measurement position corresponds to a second geometric and position deviation analysis result, and these results collectively reflect the geometric and position changes of the whole to-be-measured concrete form before and after pouring, thereby achieving comprehensive dynamic monitoring of large structures.

[0149] The application further provides a concrete form detection device based on three-dimensional laser scanning.

[0150] The device comprises a processor and a memory coupled with each other in hardware. The processor can be a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field programmable gate array (FPGA) or other types of processing chips. The memory can be a random access memory (RAM), a read-only memory (ROM), a flash memory or other types of storage media. The processor and the memory are coupled with each other, that is, the processor can read the data and programs stored in the memory and execute the programs in the memory.

[0151] The memory stores a computer program, which contains instructions and data required for implementing the concrete form detection method based on three-dimensional laser scanning.

[0152] In summary, the concrete form three-dimensional laser scanning point cloud data processing method, the concrete form detection method based on three-dimensional laser scanning and the concrete form detection device based on three-dimensional laser scanning provided by the application have the following remarkable beneficial effects:

[0153] First, the data is simplified from the data source, which completely solves the problem of data redundancy and manual "cleaning". The invention overturns the traditional working mode of "full-plate collection first, then tedious processing". When scanning with a three-dimensional laser scanner, the system synchronously receives and judges each sampling point data in real time. Only the points falling within the preset formwork template shape control key area are stored as target point data in the cache area, while a large number of irrelevant interference data are discarded. This real-time filtering mechanism at the data collection source fundamentally avoids the generation of massive redundant data, making the final target point cloud pure and small in size. As shown in Figure 11 , the target point cloud graph is extremely pure, which is in sharp contrast with Figure 7 the original point cloud graph. This completely eliminates the subsequent manual or semi-automatic "cleaning" work, greatly reduces the burden of data transmission and storage, and significantly improves the overall efficiency from scanning to obtaining usable point cloud.

[0154] Second, the detection results are quickly fed back, changing "post-acceptance" to "process control". Using the three-dimensional laser scanning point cloud data processing method for the formwork, the target point cloud obtained does not need time-consuming and laborious post-processing, and the data processing results (such as the first shape and position deviation analysis results) can be quickly analyzed after scanning. As shown in Figure 10 , the results can be presented in the form of a chromatogram in real time, providing immediate quantitative feedback for on-site adjustment. Field workers can immediately adjust the formwork shaping pre-tightening force mechanism based on the feedback results to achieve accurate control of the formwork shape and position. This rapid feedback mechanism changes the detection from the traditional "post-acceptance" to "process control", which can timely discover and correct problems when they occur, avoiding the problem of delayed detection results in traditional methods that miss the best adjustment opportunity.

[0155] Third, high-frequency dynamic deformation monitoring is possible. The invention greatly shortens the time-consuming of single detection through its efficient three-dimensional laser scanning point cloud data processing method for the formwork, making it possible to implement a three-dimensional laser scanning-based formwork detection method that includes first scanning and second scanning. By comparing the first data processing results with the second data processing results, the second shape and position deviation analysis results can be obtained, accurately quantifying the deformation of the formwork under the lateral pressure of the concrete. This high-frequency dynamic monitoring capability provides direct data support for early warning and control of formwork deformation during pouring and prevention of major quality accidents such as formwork expansion. In the traditional method, due to the high cost and long cycle of single detection, high-frequency scanning monitoring is not practical, but the method of the invention makes it possible.

[0156] Fourth, it is suitable for comprehensive detection of large and complex structures. By pre-planning the moving route of the three-dimensional laser scanner and setting multiple measuring stations on the moving route, comprehensive detection of large and complex structures can be achieved. For example, as shown in FIG. 7, for such a large structure as the arch-shaped corridor group, the operator can carry the three-dimensional laser scanner along the arch-shaped corridor, and scan at each measuring station, and the detection result can be quickly obtained at each measuring station. This way not only ensures the comprehensiveness of the detection, but also maintains high efficiency, making it possible to comprehensively and frequently monitor the quality of large and complex structures. Figure 12

[0157] The above describes the relevant content of the present application. Those skilled in the art will be able to implement the present application based on these descriptions. Based on the above content of the present description, all other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of the present application.​

Claims

1. A method for processing three-dimensional laser scanning point cloud data of concrete formwork, characterized in that: include: When the 3D laser scanner scans the concrete template to be measured at the set measurement position and in the set scanning mode, it synchronously receives the data of each sampling point collected and sent in real time by the 3D laser scanner. For each received sampling point data, the location information of the corresponding sampling point is extracted in real time, and the location information is used to determine whether the position of the sampling point falls within the set key area for concrete formwork shape and position control. If the result of the judgment is yes, the sampled point data is stored as target point data in the target point data cache area; if the result of the judgment is no, the sampled point data is discarded. After the scan is completed, a target point cloud is formed based on all target point data stored in the target point data cache, and the data processing result is obtained based on the target point cloud; The key area for formwork shape and position control is defined by the two-dimensional view of the concrete formwork and is a key area used to determine the formwork shape and position control quality of the concrete formwork to be tested. There is a mapping relationship between the image coordinate system of the two-dimensional view of the concrete formwork and the angle measurement coordinate system of the three-dimensional laser scanner, so that the position information of each sampling point can be uniquely mapped to a pixel coordinate on the two-dimensional view of the concrete formwork.

2. The method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in claim 1, characterized in that: The mapping relationship is set in the following way, which specifically includes: In the three-dimensional design model of the concrete formwork corresponding to the concrete formwork to be tested, the image coordinate system is defined. The two-dimensional perspective view of the three-dimensional design model of the concrete formwork when viewed from the origin of the image coordinate system as the perspective center is the two-dimensional view of the concrete formwork. In the two-dimensional view of the concrete formwork, a key area for controlling the shape and position of the concrete formwork is set, and the pixel coordinates of the key area for controlling the shape and position of the concrete formwork in the image coordinate system are calculated by a projection algorithm. At the measurement site of the concrete formwork to be tested, the angle measurement coordinate system of the three-dimensional laser scanner is registered with the image coordinate system, so that the three-dimensional laser scanner is placed at the set measurement position.

3. The method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in claim 2, characterized in that: The registration specifically includes: Define the global positioning reference in the three-dimensional design model of the concrete formwork as the first global positioning reference, define the global positioning reference in the measurement site as the second global positioning reference, and unify the first global positioning reference and the second global positioning reference; Determine the relative positional relationship between the image coordinate system and the first global positioning reference, and define the relative positional relationship between the image coordinate system and the first global positioning reference as the first relative positional relationship; The relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference is measured, and the relative positional relationship between the angle measurement coordinate system of the three-dimensional laser scanner and the second global positioning reference is defined as the second relative positional relationship; The pose of the 3D laser scanner is adjusted so that the second relative positional relationship is consistent with the first relative positional relationship.

4. The method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in any one of claims 1-3, characterized in that: The key area for controlling the shape and position of the concrete formwork includes the edge contour of the concrete formwork, from which the thickness of the concrete formwork can be observed.

5. The method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in claim 4, characterized in that: The concrete formwork has an arc-shaped edge profile; And / or, multiple concrete formwork shaping pre-tightening mechanisms are provided at intervals along the contour line direction corresponding to the edge contour of the concrete formwork to be tested. Each concrete formwork shaping pre-tightening mechanism is adjusted by an independent pre-tightening force adjustment device so that the concrete formwork to be tested can adapt to the shape of the shaping keel by deformation and be fixed on the keel.

6. The method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in any one of claims 1-3, characterized in that: The processing result includes the first form and position deviation analysis result obtained by comparing the target point cloud with the three-dimensional design model of the concrete template corresponding to the concrete template to be tested.

7. A method for detecting concrete formwork based on three-dimensional laser scanning, characterized in that: include: Before concrete pouring, when the 3D laser scanner is placed at the set measurement position and scanned in the set scanning mode for the first time, the first data processing result is obtained by the 3D laser scanning point cloud data processing method of the concrete template. When the 3D laser scanner is repositioned at the same set measurement position and scanned a second time using the same set scanning method during or after concrete pouring, the second data processing result is obtained through the 3D laser scanning point cloud data processing method of the concrete template. The first data processing result is compared with the second data processing result to obtain the second form and position deviation analysis result; The method for processing three-dimensional laser scanning point cloud data of concrete formwork is the method for processing three-dimensional laser scanning point cloud data of concrete formwork as described in any one of claims 1-6.

8. The concrete formwork inspection method based on three-dimensional laser scanning as described in claim 7, characterized in that: Before the first scan, a 3D laser scanner moving route is pre-planned, and at least two set measurement positions are distributed on the 3D laser scanner moving route. Before concrete pouring, when the first scan is performed at different set measurement positions according to the moving route of the three-dimensional laser scanner, the corresponding first data processing results are obtained by the concrete formwork three-dimensional laser scanning point cloud data processing method. During or after concrete pouring, when the second scan is performed sequentially at different set measurement positions according to the moving route of the three-dimensional laser scanner, the corresponding second data processing results are obtained by the concrete formwork three-dimensional laser scanning point cloud data processing method. Each first data processing result is compared with the corresponding second data processing result to obtain the corresponding second form and position deviation analysis result.

9. The concrete formwork inspection method based on three-dimensional laser scanning as described in claim 8, characterized in that: The concrete template to be tested is used to pour a group of arched corridors arranged in a crisscross pattern; the moving route of the three-dimensional laser scanner is set along the arched passage of the group of arched corridors.

10. A concrete formwork inspection device based on three-dimensional laser scanning, characterized in that: It includes a processor and a memory coupled to each other, the memory storing a computer program that, when executed by the processor, implements the concrete formwork detection method based on three-dimensional laser scanning as described in any one of claims 7-9.

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