Building inspection method, device and system based on BIM (Building Information Modeling) technology

Abstract

The invention discloses a building inspection method, device and system based on a BIM technology, and relates to the technical field of building inspection, and the method comprises the steps: obtaining an original BIM model of a building; the original BIM model of the building is preprocessed, and the inner wall and the outer wall of the building are screened out through semantic information of the BIM model; calculating the size of the view field of the unmanned aerial vehicle camera; performing gridding processing on the to-be-inspected area model to obtain a gridding BIM model of the building; determining a waypoint of the unmanned aerial vehicle; solving the shortest path in the waypoints of all the unmanned aerial vehicles by using a genetic algorithm; testing the maximum flight distance of the unmanned aerial vehicle with the single battery, and dividing the whole route into a plurality of route sections by using the maximum distance to obtain an optimal path; and calculating and converting the unmanned aerial vehicle route task parameters under the BIM coordinate system. By arranging the model construction module and the path calculation module, the inspection time is effectively saved, and the image quality and the overall coverage rate are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of building inspection, and in particular to a building inspection method, device and system based on BIM technology. Background Art

[0002] Urban high-rise buildings have rapidly become the main form of modern urban construction due to their high land utilization rate, small footprint and more beautiful appearance. Although high-rise buildings have many advantages, due to the extended service life, aging of materials and construction defects, wall peeling, bulging and cracks can easily cause safety accidents, thus causing huge economic losses to society and the people. Therefore, the inspection and maintenance of the walls of urban high-rise buildings has become particularly important in protecting public safety and reducing economic losses.

[0003] The purpose of coverage path planning is to determine the path that allows the robot to explore the workspace in detail, thereby ensuring complete coverage of the structure inspection. In actual structural inspection, although some research works have used coverage path planning methods in different structural inspections, few scholars have paid attention to how to incorporate sensor size and accuracy and coverage evaluation into coverage path planning. Therefore, combining sensor size and accuracy and extensively evaluating coverage in the coverage path planning process is still considered an open research area and needs further exploration. In addition, the inclusion of drone battery life in path planning and the positioning accuracy of drones executing routes in reality have not been considered. Summary of the invention

[0004] In order to solve the above technical problems, a building inspection method, device and system based on BIM technology are provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: Building inspection methods based on BIM technology include: Extract the area to be inspected in the building and obtain the original BIM model of the building; By preprocessing the original BIM model of the building, the semantic information of the BIM model is used to filter out the inner and outer walls of the building, and the entire interior space is defined as a room; Determine the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera's parameters and safe distance; Based on the drone camera field of view, the model of the area to be inspected is gridded to obtain a gridded BIM model of the building; Based on the gridded BIM model of the building, determine the specific location where the drone collects image data of the complete target inspection area, i.e. the drone’s waypoint; Genetic algorithm is used to solve the shortest path among all the UAV’s waypoints; Test the maximum distance a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set up a drone battery refueling point at the end of each route, and get the optimal route; The UAV route mission parameters in the BIM coordinate system are calculated and converted, and the UAV executes the optimized route in the real environment.

[0006] Preferably, determining the safe flight distance of the drone according to the clarity of the drone photo and environmental factors, and obtaining the size of the drone camera field of view through the camera parameters and the safe distance specifically include: Preset the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors; Get the camera parameters of the drone; The area of ​​the object that is photographed through the lens to form a visible image on the focal plane, that is, the range of objects that can be covered by the camera lens constitutes the field of view of the drone camera; Calculate the size of the drone camera's field of view using the camera field of view formula based on the drone's camera parameters; The camera field of view formula is: , In the formula, , are the width and height of the drone camera’s field of view, , are the width and height of the drone camera sensor, This is the safe distance for the drone camera to face the wall. is the focal length of the drone camera.

[0007] Preferably, the gridding of the model of the area to be inspected based on the field of view of the drone camera to obtain the gridded BIM model of the building specifically includes: Based on the BIM model, the wall areas of the space defined as the room are divided into six types: front, back, left, right, top and bottom; Get all the rectangular areas to be inspected belonging to the front direction, defined as faces, each face is composed of four lines, each line is composed of a starting point and an end point, and each point is represented by XYZ coordinates; Filter out the vertex in the upper left corner of each face, and form a fixed rectangle with the same size as the drone camera's field of view based on this vertex; Get the geometric information of the length and width of each face, and divide it by the height and width of the drone camera's field of view to get the maximum number of drone camera fields of view that can be covered on each face; The fixed rectangle formed by the upper left corner of each face is translated according to the calculated field of view of the drone camera until the entire surface is completely covered; The covering principle in the back, left, right, top and bottom directions is consistent with that in the front direction. At the same time, all surfaces of the target areas to be inspected are completely covered to obtain a gridded BIM model of the building.

[0008] Preferably, the gridded BIM model of the building is used to determine the specific location where the drone collects the image data of the complete target inspection area, that is, the waypoints of the drone specifically include: In each room, the plane where the drone’s waypoint is located is parallel to each target inspection surface; The plane where the drone’s waypoints are located is defined as a virtual drone working plane, and all the waypoints in each room are distributed on this working plane; The rectangular center point of the drone camera field of view in each area is projected onto the corresponding drone working plane, and the projection point on the working plane is output as the drone's waypoint.

[0009] Preferably, the method of using a genetic algorithm to solve the shortest path among all the waypoints of the drone specifically includes: S101: Generate multiple feasible paths, output them as a population, and calculate the fitness value of each path using the inverse of the total length of the path; S102: Select two parent paths with the largest fitness values ​​from the population; S103: performing a waypoint cross process on the selected excellent parent path to generate a child path; S104: performing a first type of mutation processing on the offspring path based on a first preset probability, selecting two genes, i.e., waypoints, to exchange positions; S105: performing a second type of mutation processing on the offspring path based on the second preset probability, selecting two genes and moving one of the genes to the back of the other gene, and shifting the gene segment between the two genes forward to complete the process; S106: performing a third type of mutation processing on the offspring path based on a third preset probability, selecting an interval and flipping the genes in the entire interval; S107: Evaluate the offspring path according to the fitness value; S108: Determine whether the fitness value of the new child path is greater than the fitness value of the parent path. If so, add the new child path to the population to form a better population. If not, do not output. S109: Determine whether the number of iterations is equal to a preset threshold. If so, end the algorithm and output the path with the largest fitness value in the current population as the shortest path. If not, return to step S102.

[0010] Preferably, the calculation and conversion of the UAV route mission parameters in the BIM coordinate system, and the UAV executing the optimized route in the real environment specifically include: The flight direction of the drone indicates the direction in which the drone is moving and is aligned with the north, east, and down directions of the WGS84 coordinate system; The flight direction of the drone ranges from 0° to 360°. The true north direction of the WGS84 coordinate system corresponds to 0° of the drone's flight direction, and other directions are superimposed in a clockwise rotation; The longitude and latitude of the starting point of the UAV are measured by a longitude and latitude surveyor; Based on the flight direction of the drone, the longitude and latitude formula is used to calculate the longitude and latitude of the drone waypoint; The latitude and longitude formula is: , In the formula, are the longitude and latitude of the previous point in the drone’s route, are the longitude and latitude of the last point in the drone route, D is the distance between the first and last points, and R is the radius of the earth. The flight direction of the drone.

[0011] Furthermore, a building inspection electronic device based on BIM technology is proposed, comprising: at least one processor; and a memory connected to the at least one processor in communication; wherein: The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned building inspection method based on BIM technology.

[0012] Furthermore, a building inspection system based on BIM technology is proposed, which is used to implement the building inspection method based on BIM technology as described above, including: A model building module, wherein the model building module is used to extract the area to be inspected in the building, obtain the original BIM model of the building, pre-process the original BIM model of the building, use the semantic information of the BIM model to screen out the inner and outer walls of the building, and define the entire interior space as a room, determine the safe flight distance of the drone according to the clarity of the drone photo and environmental factors, obtain the size of the drone camera field of view through the camera parameters and the safe distance, and grid the model of the area to be inspected based on the drone camera field of view to obtain a gridded BIM model of the building; The path calculation module is used to determine the specific location where the drone collects the image data of the complete target inspection area, that is, the drone's waypoint, based on the gridded BIM model of the building; use a genetic algorithm to solve the shortest path among all the drone's waypoints; test the maximum distance that a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set a battery supply point for the drone at the end of each route, and obtain the optimal path; calculate and convert the drone route mission parameters in the BIM coordinate system, and the drone executes the optimized route in a real environment.

[0013] Optionally, the model building module specifically includes: An original model construction unit, wherein the original model construction unit is used to extract the area to be inspected in the building and obtain the original BIM model of the building; A model preprocessing unit, wherein the model preprocessing unit is used to preprocess the original BIM model of the building, filter out the inner and outer walls of the building by using the semantic information of the BIM model, and define the entire interior space as a room; A camera field of view calculation unit, which is used to determine the safe flight distance of the drone according to the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera parameters and the safe distance; The grid model construction unit is used to grid the model of the area to be inspected based on the field of view of the drone camera to obtain a gridded BIM model of the building.

[0014] Optionally, the path calculation module specifically includes: A waypoint calculation unit, which is used to determine the specific location where the drone collects image data of the complete target inspection area, i.e., the waypoint of the drone, based on the gridded BIM model of the building; A shortest path solving unit, wherein the shortest path solving unit is used to solve the shortest path among all the waypoints of the UAV using a genetic algorithm; An optimal path solving unit, which is used to test the maximum distance that a single-battery UAV can fly, divide the overall route into multiple routes using the maximum distance, set a battery refueling point for the UAV at the end of each route, and obtain the optimal path; A route parameter conversion unit is used to calculate and convert the UAV route mission parameters in the BIM coordinate system, and the UAV executes the optimized route in a real environment.

[0015] Compared with the prior art, the present invention has the following beneficial effects: By setting up the model building module and the path calculation module, the inspection time is effectively saved, and the image quality and overall coverage are improved. On the basis of obtaining the optimal path of the UAV, the longitude and latitude are solved based on the flight direction and the distance between adjacent waypoints, and a fast and fully automatic solution method is obtained. Considering the battery life of the UAV, a method for exploring the setting of supply points is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of the building inspection method based on BIM technology of the present invention; Figure 2 This is a flow chart of the method for obtaining the size of the field of view of the drone camera of the present invention; Figure 3 This is a flow chart of a method for gridding a model of an area to be inspected according to the present invention; Figure 4 A flow chart of a method for determining a waypoint of a drone according to the present invention; Figure 5 A flow chart of a method for solving the shortest path among all the waypoints of the UAV using a genetic algorithm according to the present invention; Figure 6 This is a flow chart of the method for calculating and converting the UAV route mission parameters in the BIM coordinate system of the present invention. DETAILED DESCRIPTION

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0018] Reference Figure 1 As shown in the figure, the building inspection method based on BIM technology includes: Extract the area to be inspected in the building and obtain the original BIM model of the building; By preprocessing the original BIM model of the building, the semantic information of the BIM model is used to filter out the inner and outer walls of the building, and the entire interior space is defined as a room; Determine the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera's parameters and safe distance; Based on the drone camera field of view, the model of the area to be inspected is gridded to obtain a gridded BIM model of the building; Based on the gridded BIM model of the building, determine the specific location where the drone collects image data of the complete target inspection area, i.e. the drone’s waypoint; Genetic algorithm is used to solve the shortest path among all the UAV’s waypoints; Test the maximum distance a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set up a drone battery refueling point at the end of each route, and get the optimal route; The UAV route mission parameters in the BIM coordinate system are calculated and converted, and the UAV executes the optimized route in the real environment.

[0019] As shown in Figure 2, the safe flight distance of the drone is determined according to the clarity of the drone's photo and environmental factors. The size of the drone's camera field of view is obtained through the camera parameters and the safe distance. Specifically, the following are included: Preset the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors; Get the camera parameters of the drone; The area of ​​the object that is photographed through the lens to form a visible image on the focal plane, that is, the range of objects that can be covered by the camera lens constitutes the field of view of the drone camera; Calculate the size of the drone camera's field of view using the camera field of view formula based on the drone's camera parameters; The camera field of view formula is: , In the formula, , are the width and height of the drone camera’s field of view, , are the width and height of the drone camera sensor, This is the safe distance for the drone camera to face the wall. is the focal length of the drone camera.

[0020] The field of view of a drone camera refers to the area covered by the visible image of the subject through the lens on the focal plane, that is, the range of objects that the camera lens can cover. It plays a decisive role in the complete inspection of the entire target area. The closer the drone camera is to the wall, the smaller the range that the camera can shoot, the smaller the field of view of the drone camera, and the clearer the image; conversely, the larger the range, the larger the field of view of the drone camera, and the blurrier the image.

[0021] As shown in Figure 3, based on the field of view of the drone camera, the model of the area to be inspected is gridded to obtain a gridded BIM model of the building, which specifically includes: Based on the BIM model, the wall areas of the space defined as the room are divided into six types: front, back, left, right, top and bottom; Get all the rectangular areas to be inspected belonging to the front direction, defined as faces, each face is composed of four lines, each line is composed of a starting point and an end point, and each point is represented by XYZ coordinates; Filter out the vertex in the upper left corner of each face, and form a fixed rectangle with the same size as the drone camera's field of view based on this vertex; Get the geometric information of the length and width of each face, and divide it by the height and width of the drone camera's field of view to get the maximum number of drone camera fields of view that can be covered on each face; The fixed rectangle formed by the upper left corner of each face is translated according to the calculated field of view of the drone camera until the entire surface is completely covered; The covering principle in the back, left, right, top and bottom directions is consistent with that in the front direction. At the same time, all surfaces of the target areas to be inspected are completely covered to obtain a gridded BIM model of the building.

[0022] Gridding the inspection area based on the field of view size is a very important step in realizing drone coverage path planning. In this paper, the field of view of the drone camera is defined as a rectangular unit, and the entire high-rise building is divided into a finite set of rectangular units. Considering the overlap, the target area to be inspected can be completely covered by several rectangular units.

[0023] As shown in Figure 4, based on the gridded BIM model of the building, the specific location where the drone collects the image data of the complete target inspection area is determined, that is, the waypoints of the drone specifically include: In each room, the plane where the drone’s waypoint is located is parallel to each target inspection surface; The plane where the drone’s waypoints are located is defined as a virtual drone working plane, and all the waypoints in each room are distributed on this working plane; The rectangular center point of the drone camera field of view in each area is projected onto the corresponding drone working plane, and the projection point on the working plane is output as the drone's waypoint.

[0024] The waypoints of a drone represent a set of optimal locations for the drone to take photos, which can help the drone to completely inspect the entire building. In order to improve the efficiency of data collection, many studies have focused on minimizing the number of viewpoints and ignored the coverage rate, but this study requires the minimum number of viewpoints to enable the drone to safely perform tasks and collect complete image data.

[0025] As shown in Figure 5, using genetic algorithm to solve the shortest path among all UAV waypoints specifically includes: S101: Generate multiple feasible paths, output them as a population, and calculate the fitness value of each path using the inverse of the total length of the path; S102: Select two parent paths with the largest fitness values ​​from the population; S103: performing a waypoint cross process on the selected excellent parent path to generate a child path; S104: performing a first type of mutation processing on the offspring path based on a first preset probability, selecting two genes, i.e., waypoints, to exchange positions; S105: performing a second type of mutation processing on the offspring path based on the second preset probability, selecting two genes and moving one of the genes to the back of the other gene, and shifting the gene segment between the two genes forward to complete the process; S106: performing a third type of mutation processing on the offspring path based on a third preset probability, selecting an interval and flipping the genes in the entire interval; S107: Evaluate the offspring path according to the fitness value; S108: Determine whether the fitness value of the new child path is greater than the fitness value of the parent path. If so, add the new child path to the population to form a better population. If not, do not output. S109: Determine whether the number of iterations is equal to a preset threshold. If so, end the algorithm and output the path with the largest fitness value in the current population as the shortest path. If not, return to step S102.

[0026] Genetic algorithm is one of the common methods for solving optimization problems. It is an algorithm derived from biological genetics and evolution. The core idea is to gradually approach the optimal solution by continuously selecting, eliminating, reorganizing and iterating individuals in the first generation population. Genetic algorithm cannot obtain the optimal solution, but only the approximate solution closest to the optimal solution. In the process of iteration, individuals that are better than the parent generation will gradually appear in the population. When a child with the strongest adaptability appears, this child has a high probability of being the optimal solution required by the problem.

[0027] As shown in Figure 6, the UAV route mission parameters in the BIM coordinate system are calculated and converted. The optimized route executed by the UAV in the real environment specifically includes: The flight direction of the drone indicates the direction in which the drone is moving and is aligned with the north, east, and down directions of the WGS84 coordinate system; The flight direction of the drone ranges from 0° to 360°. The true north direction of the WGS84 coordinate system corresponds to 0° of the drone's flight direction, and other directions are superimposed in a clockwise rotation; The longitude and latitude of the starting point of the UAV are measured by a longitude and latitude surveyor; Based on the flight direction of the drone, the longitude and latitude formula is used to calculate the longitude and latitude of the drone waypoint; The latitude and longitude formula is: , In the formula, are the longitude and latitude of the previous point in the drone’s route, are the longitude and latitude of the last point in the drone route, D is the distance between the first and last points, and R is the radius of the earth. The flight direction of the drone.

[0028] The WGS-84 coordinate system is an internationally adopted geocentric coordinate system with the origin at the center of mass of the earth. The Z axis of the geocentric rectangular coordinate system points to the direction of the earth's pole as defined by the International Time Service, and the X axis points to the intersection of the zero meridian plane and the equator. The Y axis is perpendicular to the Z and X axes to form a right-handed coordinate system, which is called the 1984 World Geodetic Coordinate System.

[0029] Furthermore, based on the same inventive concept as the above-mentioned building inspection method based on BIM technology, the present solution also proposes a building inspection electronic device based on BIM technology, including: at least one processor; and a memory connected to the at least one processor in communication; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned building inspection method based on BIM technology.

[0030] Furthermore, based on the same inventive concept as the above-mentioned building inspection method based on BIM technology, the present solution also proposes a building inspection system based on BIM technology, including: a model construction module, the model construction module is used to extract the area to be inspected in the building, obtain the original BIM model of the building, pre-process the original BIM model of the building, use the semantic information of the BIM model to screen out the inner and outer walls of the building, and define the entire internal space as a room, determine the safe flight distance of the drone according to the clarity of the drone photography and environmental factors, obtain the size of the drone camera field of view through the camera parameters and the safe distance, and grid the model of the area to be inspected based on the drone camera field of view to obtain a gridded BIM model of the building; The path calculation module is used to determine the specific location where the drone collects the image data of the complete target inspection area, that is, the drone's waypoint, based on the gridded BIM model of the building; use a genetic algorithm to solve the shortest path among all the drone's waypoints; test the maximum distance that a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set a battery supply point for the drone at the end of each route, and obtain the optimal path; calculate and convert the drone route mission parameters in the BIM coordinate system, and the drone executes the optimized route in a real environment.

[0031] The model building modules include: An original model construction unit, wherein the original model construction unit is used to extract the area to be inspected in the building and obtain the original BIM model of the building; A model preprocessing unit, wherein the model preprocessing unit is used to preprocess the original BIM model of the building, filter out the inner and outer walls of the building by using the semantic information of the BIM model, and define the entire interior space as a room; A camera field of view calculation unit, which is used to determine the safe flight distance of the drone according to the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera parameters and the safe distance; A grid model construction unit, wherein the grid model construction unit is used to grid the model of the area to be inspected based on the field of view of the drone camera to obtain a grid BIM model of the building; The path calculation module specifically includes: A waypoint calculation unit, which is used to determine the specific location where the drone collects image data of the complete target inspection area, i.e., the waypoint of the drone, based on the gridded BIM model of the building; A shortest path solving unit, wherein the shortest path solving unit is used to solve the shortest path among all the waypoints of the UAV using a genetic algorithm; An optimal path solving unit, which is used to test the maximum distance that a single-battery UAV can fly, divide the overall route into multiple routes using the maximum distance, set a battery refueling point for the UAV at the end of each route, and obtain the optimal path; A route parameter conversion unit is used to calculate and convert the UAV route mission parameters in the BIM coordinate system, and the UAV executes the optimized route in a real environment.

[0032] Furthermore, the present solution also proposes a computer-readable storage medium on which a computer-readable program is stored. When the computer-readable program is called, the above-mentioned building inspection method based on BIM technology is executed.

[0033] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state drive (SSD).

[0034] To sum up, the advantages of the present invention are: by setting up a model building module and a path calculation module, the inspection time is effectively saved, and the image quality and overall coverage are improved. On the basis of obtaining the optimal path of the drone, the longitude and latitude are solved based on the flight direction and the distance between adjacent waypoints to obtain a fast and fully automatic solution method. Taking into account the battery life of the drone, a method for exploring the setting of supply points is obtained.

[0035] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. Building inspection method based on BIM technology, It is characterized in that include: Extract the area to be inspected in the building and obtain the original BIM model of the building; By preprocessing the original BIM model of the building, the semantic information of the BIM model is used to filter out the inner and outer walls of the building, and the entire interior space is defined as a room; Determine the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera's parameters and safe distance; Based on the drone camera field of view, the model of the area to be inspected is gridded to obtain a gridded BIM model of the building; Based on the gridded BIM model of the building, determine the specific location where the drone collects image data of the complete target inspection area, i.e. the drone’s waypoint; Genetic algorithm is used to solve the shortest path among all the UAV’s waypoints; Test the maximum distance a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set up a drone battery refueling point at the end of each route, and get the optimal route; The UAV route mission parameters in the BIM coordinate system are calculated and converted, and the UAV executes the optimized route in the real environment.

2. The building inspection method based on BIM technology according to claim 1, It is characterized in that Determining the safe flight distance of the drone based on the clarity of the drone photo and environmental factors, and obtaining the size of the drone camera field of view through the camera parameters and the safe distance specifically include: Preset the safe flight distance of the drone based on the clarity of the drone's photos and environmental factors; Get the camera parameters of the drone; The area of ​​the object that is photographed through the lens to form a visible image on the focal plane, that is, the range of objects that can be covered by the camera lens constitutes the field of view of the drone camera; Calculate the size of the drone camera's field of view using the camera field of view formula based on the drone's camera parameters; The camera field of view formula is: , In the formula, , are the width and height of the drone camera’s field of view, , are the width and height of the drone camera sensor, This is the safe distance for the drone camera to face the wall. is the focal length of the drone camera.

3. The building inspection method based on BIM technology according to claim 2, It is characterized in that The method of gridding the model of the area to be inspected based on the field of view of the drone camera to obtain the gridded BIM model of the building specifically includes: Based on the BIM model, the wall areas of the space defined as the room are divided into six types: front, back, left, right, top and bottom; Get all the rectangular areas to be inspected belonging to the front direction, defined as faces, each face is composed of four lines, each line is composed of a starting point and an end point, and each point is represented by XYZ coordinates; Filter out the vertex in the upper left corner of each face, and form a fixed rectangle with the same size as the drone camera's field of view based on this vertex; Get the geometric information of the length and width of each face, and divide it by the height and width of the drone camera's field of view to get the maximum number of drone camera fields of view that can be covered on each face; The fixed rectangle formed by the upper left corner of each face is translated according to the calculated field of view of the drone camera until the entire surface is completely covered; The covering principle in the back, left, right, top and bottom directions is consistent with that in the front direction. At the same time, all surfaces of the target areas to be inspected are completely covered to obtain a gridded BIM model of the building.

4. The building inspection method based on BIM technology according to claim 3, It is characterized in that The gridded BIM model of the building is used to determine the specific location where the drone collects the image data of the complete target inspection area, that is, the waypoints of the drone specifically include: In each room, the plane where the drone’s waypoint is located is parallel to each target inspection surface; The plane where the drone’s waypoints are located is defined as a virtual drone working plane, and all the waypoints in each room are distributed on this working plane; The rectangular center point of the drone camera field of view in each area is projected onto the corresponding drone working plane, and the projection point on the working plane is output as the drone's waypoint.

5. The building inspection method based on BIM technology according to claim 4, It is characterized in that The method of using the genetic algorithm to solve the shortest path among all the waypoints of the UAV specifically includes: S101: Generate multiple feasible paths, output them as a population, and calculate the fitness value of each path using the inverse of the total length of the path; S102: Select two parent paths with the largest fitness values ​​from the population; S103: performing a waypoint cross process on the selected excellent parent path to generate a child path; S104: performing a first type of mutation processing on the offspring path based on a first preset probability, selecting two genes, i.e., waypoints, to exchange positions; S105: performing a second type of mutation processing on the offspring path based on the second preset probability, selecting two genes and moving one of the genes to the back of the other gene, and shifting the gene segment between the two genes forward to complete the process; S106: performing a third type of mutation processing on the offspring path based on a third preset probability, selecting an interval and flipping the genes in the entire interval; S107: Evaluate the offspring path according to the fitness value; S108: Determine whether the fitness value of the new child path is greater than the fitness value of the parent path. If so, add the new child path to the population to form a better population. If not, do not output. S109: Determine whether the number of iterations is equal to a preset threshold. If so, end the algorithm and output the path with the largest fitness value in the current population as the shortest path. If not, return to step S102.

6. The building inspection method based on BIM technology according to claim 5, It is characterized in that The calculation and conversion of the UAV route mission parameters in the BIM coordinate system and the execution of the optimized route by the UAV in the real environment specifically include: The flight direction of the drone indicates the direction in which the drone is moving and is aligned with the north, east, and down directions of the WGS84 coordinate system; The flight direction of the drone ranges from 0° to 360°. The true north direction of the WGS84 coordinate system corresponds to 0° of the drone's flight direction, and other directions are superimposed in a clockwise rotation; The longitude and latitude of the starting point of the UAV are measured by a longitude and latitude surveyor; Based on the flight direction of the drone, the longitude and latitude formula is used to calculate the longitude and latitude of the drone waypoint; The latitude and longitude formula is: , In the formula, are the longitude and latitude of the previous point in the drone’s route, are the longitude and latitude of the last point in the drone route, D is the distance between the first and last points, and R is the radius of the earth. The flight direction of the drone.

7. Building inspection electronic device based on BIM technology, It is characterized in that include: at least one processor; And, a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the building inspection method based on BIM technology as described in any one of claims 1-6.

8. A building inspection system based on BIM technology, used to implement the building inspection method based on BIM technology as described in any one of claims 1 to 6, It is characterized in that include: A model building module, wherein the model building module is used to extract the area to be inspected in the building, obtain the original BIM model of the building, pre-process the original BIM model of the building, use the semantic information of the BIM model to screen out the inner and outer walls of the building, and define the entire interior space as a room, determine the safe flight distance of the drone according to the clarity of the drone photo and environmental factors, obtain the size of the drone camera field of view through the camera parameters and the safe distance, and grid the model of the area to be inspected based on the drone camera field of view to obtain a gridded BIM model of the building; The path calculation module is used to determine the specific location where the drone collects the image data of the complete target inspection area, that is, the drone's waypoint, based on the gridded BIM model of the building; use a genetic algorithm to solve the shortest path among all the drone's waypoints; test the maximum distance that a single-battery drone can fly, use the maximum distance to divide the overall route into multiple routes, set the drone's battery supply point at the end of each route, and obtain the optimal path; calculate and convert the drone route mission parameters in the BIM coordinate system, and the drone executes the optimized route in a real environment.

9. The building inspection system based on BIM technology according to claim 8, It is characterized in that The model building module specifically includes: An original model construction unit, wherein the original model construction unit is used to extract the area to be inspected in the building and obtain the original BIM model of the building; A model preprocessing unit, wherein the model preprocessing unit is used to preprocess the original BIM model of the building, filter out the inner and outer walls of the building by using the semantic information of the BIM model, and define the entire interior space as a room; A camera field of view calculation unit, which is used to determine the safe flight distance of the drone according to the clarity of the drone's photos and environmental factors, and obtain the size of the drone's camera field of view through the camera parameters and the safe distance; A grid model construction unit, wherein the grid model construction unit is used to grid the model of the area to be inspected based on the field of view of the drone camera to obtain a grid BIM model of the building; The path calculation module specifically includes: A waypoint calculation unit, which is used to determine the specific location where the drone collects image data of the complete target inspection area, i.e., the waypoint of the drone, based on the gridded BIM model of the building; A shortest path solving unit, wherein the shortest path solving unit is used to solve the shortest path among all the waypoints of the UAV using a genetic algorithm; An optimal path solving unit, which is used to test the maximum distance that a single-battery UAV can fly, divide the overall route into multiple routes using the maximum distance, set a battery refueling point for the UAV at the end of each route, and obtain the optimal path; A route parameter conversion unit is used to calculate and convert the UAV route mission parameters in the BIM coordinate system, and the UAV executes the optimized route in a real environment.

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