Construction method and system of urban real scene 3D model based on BIM

Abstract

The present invention proposes a method and system for constructing a real-life three-dimensional model of a city based on BIM, and belongs to the technical field of three-dimensional modeling and urban aerial survey. The method includes: obtaining large-scale topographic map data of the city, extracting water systems, roads, and core area buildings as basic geographic entities based on BIM; determining multiple aerial photography partitions, using aerial photography equipment to shoot each aerial photography partition, and obtaining an oblique photography three-dimensional model corresponding to each aerial photography partition; performing model modification on the oblique photography three-dimensional model to obtain an oblique photography real-life three-dimensional model; obtaining laser point cloud data corresponding to each basic geographic entity, fusing the oblique photography real-life three-dimensional model, and obtaining a real-life three-dimensional model of the city; when there are multiple consecutive interactive operations within the scope of the target basic geographic entity, the multiple consecutive interactive operations are determined as idempotent operations. The real-life three-dimensional scene model of the city constructed by the present invention can achieve rapid measurement, query, and positioning through associated attribute expansion.

Description

Technical Field

[0001] The present invention belongs to the technical field of three-dimensional modeling and urban aerial survey, and in particular to a method and system for constructing a real-scene three-dimensional model of a city based on BIM, a computer-readable storage medium for implementing the method, a computer program product and an electronic device. Background Art

[0002] In recent years, with the vigorous development of the combination of real-life models and architectural BIM models, they have been widely used in various fields related to cities, such as management, analysis and simulation. Large-scale, high-precision three-dimensional city models need to be created by integrating multiple data sources, and the construction of an urban platform based on the integration of real-life models and BIM has become an important manifestation of the modernization of today's urban governance capabilities.

[0003] China's authorized invention patent CN106327573B proposes a real-scene 3D modeling method for urban buildings. By organically combining aerial oblique photogrammetry with ground vehicle-mounted mobile measurement, the extraction and processing of all-round spatial information of air-ground integration can be performed, so that the real-scene 3D model of urban buildings can be quickly established, which can make up for the shortcomings of aerial oblique photography near the ground to the greatest extent and give full play to the advantages of vehicle-mounted mobile measurement near the ground.

[0004] However, on the one hand, as cities grow larger and larger, the amount of data in city-level real-life 3D models and some major public facilities has reached TB level. Frequent responses on the human-computer interaction interface will cause obvious jams and delays in data transmission, affecting the visualization effect and human-computer interaction experience. On the other hand, in order to ensure the high efficiency of real-life 3D model production and updating, high precision of position and geometry, high restoration of structure and texture, and high utilization of results, urban real-life 3D models need to aggregate and integrate multi-source heterogeneous and multi-dimensional data. The space utilization and concurrent speed of standardized storage and transmission of multi-source heterogeneous data have always been the main bottleneck restricting performance in the modeling process.

[0005] How to ensure that the urban real-scene 3D model integrated into the BIM human-computer interaction interface will not have data transmission and display delays due to frequent user interactions during visualization interaction, while also being able to fully utilize the different dimensional values ​​of multi-source heterogeneous data to standardize its processing process, is a technical problem that urgently needs to be solved in the current urban real-scene 3D model. Summary of the invention

[0006] In response to the above technical problems, the present invention provides a method and system for constructing a real-life three-dimensional model of a city based on BIM, a computer-readable storage medium, a computer program product, and an electronic device for implementing the method.

[0007] In a first aspect of the present invention, a method for constructing a real-scene three-dimensional model of a city based on BIM is proposed. The method is jointly executed by an aerial photography device and a ground device, and the method comprises the following steps:

[0008] Obtain existing large-scale topographic map data of the city, and extract water systems, roads, and core area buildings as basic geographic entities based on BIM;

[0009] Based on the constructed multiple basic geographic entities, multiple aerial photography sub-areas are determined, and each aerial photography sub-area is photographed by an aerial photography device to obtain an oblique photography three-dimensional model corresponding to each aerial photography sub-area, wherein each oblique photography three-dimensional model includes at least one basic geographic entity;

[0010] Performing model modification on the oblique photography three-dimensional model to obtain an oblique photography real-scene three-dimensional model;

[0011] Acquire the laser point cloud data corresponding to each basic geographic entity, fuse the oblique photography real-scene 3D model with the laser point cloud data, and obtain the real-scene 3D model of the city;

[0012] Wherein, at least one ground device is configured within the range of each basic geographic entity, and the plurality of aerial photography partitions are determined according to the connection serial number of the ground device, and the aerial photography device photographs each aerial photography partition in sequence based on the connection serial number.

[0013] The aerial photography equipment is a drone equipped with a laser radar, and the ground equipment is a movable ground photography equipment equipped with a wireless communication module.

[0014] The step of obtaining the laser point cloud data corresponding to each basic geographic entity and fusing the oblique photography real-scene 3D model with the laser point cloud data to obtain the real-scene 3D model of the city specifically includes:

[0015] For each basic geographic entity, two-dimensional vector primitives corresponding to water systems, roads, and core area buildings are extracted based on BIM; the two-dimensional vector primitives can be stretched into LOD1.3 level white models;

[0016] Based on the oblique photography 3D model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity, a 3D vector primitive is produced; the 3D vector primitive is a LOD2 level white model with a top structure;

[0017] A three-dimensional model monomer with fine texture and external structure is produced by reconstructing the monomer; the three-dimensional model monomer is a LOD3 level model monomer.

[0018] The two-dimensional vector primitives, three-dimensional vector primitives and three-dimensional model monomers are integrated to obtain a three-dimensional model of the real city scene.

[0019] After obtaining the real-scene three-dimensional model of the city, the method further includes:

[0020] Integrating the real-scene three-dimensional model of the city into the BIM;

[0021] In response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, determining a target basic geographic entity range determined by the interactive operation;

[0022] When there are multiple consecutive interactive operations within the target basic geographic entity range, determining the multiple consecutive interactive operations as idempotent operations;

[0023] Respond to user demands based on the idempotent operation.

[0024] The step of obtaining the laser point cloud data corresponding to each basic geographic entity specifically includes:

[0025] The laser radar-equipped drone performs image control measurement on each aerial photography partition to obtain a point cloud data set;

[0026] The laser point cloud data is obtained by solving the point cloud data set, performing coordinate transformation and framing output.

[0027] Part or all of the steps of the method for constructing a real-life three-dimensional model of a city based on BIM described in the first aspect can be automatically implemented through various forms of electronic devices and computer program instructions; the computer program instructions can be stored in storage media of different forms and loaded into computer electronic devices for execution.

[0028] Therefore, in the second aspect of the present invention, a computer-readable storage medium is also provided for storing computer instructions. When the computer instructions are executed on an electronic device, the electronic device executes the method for constructing a real-life three-dimensional model of a city based on BIM as described in the first aspect.

[0029] In the third aspect of the present invention, an electronic device is also proposed, comprising a processor and a memory, wherein the memory is used to store instructions, and the processor is used to call the instructions in the memory, so that the electronic device executes the method for constructing a real-life three-dimensional model of a city based on BIM as described in the first aspect above.

[0030] In a fourth aspect of the present invention, a computer program product is also proposed, the product comprising a computer program, and when the computer program is executed, the method for constructing a real-life three-dimensional urban model based on BIM described in the first aspect is implemented.

[0031] Corresponding to the technical solution of the method, in order to execute the method, in the fifth aspect of the present invention, a system for constructing a real-life three-dimensional model of a city based on BIM is proposed. The system includes an unmanned aerial vehicle (UAV) aerial photography device equipped with a laser radar and a movable ground photography device equipped with a wireless communication module. The movable ground photography device interacts with the UAV for data instructions via wireless communication.

[0032] The BIM obtains existing large-scale topographic map data of the city, extracts water systems, roads, and core area buildings as basic geographic entities, and determines multiple aerial photography zones based on the constructed multiple basic geographic entities;

[0033] Assigning a plurality of numbered movable ground photographing devices to the plurality of aerial photography subareas, wherein the aerial photography devices sequentially photograph each aerial photography subarea based on the guidance of the numbered movable ground photographing devices, and obtaining an oblique photography three-dimensional model corresponding to each aerial photography subarea and laser point cloud data corresponding to each basic geographic entity;

[0034] The BIM fuses the oblique photography real-scene three-dimensional model with the laser point cloud data to obtain a real-scene three-dimensional model of the city;

[0035] Integrating the real-scene three-dimensional model of the city into the BIM;

[0036] In response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, a regional city real-scene three-dimensional model corresponding to at least one basic geographic entity corresponding to the interactive operation is displayed in the human-computer interaction interface.

[0037] The system also includes an idempotent processing unit;

[0038] In response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, the idempotent processing unit determines a target basic geographic entity range determined by the interactive operation;

[0039] When there are multiple consecutive interactive operations within the target basic geographic entity range, the idempotent processing unit determines the multiple consecutive interactive operations as idempotent operations;

[0040] Respond to user demands based on the idempotent operation.

[0041] The BIM integrates the oblique photography real-scene 3D model with the laser point cloud data to obtain a real-scene 3D model of the city, specifically including:

[0042] For each basic geographic entity, extract the two-dimensional vector primitives corresponding to the water system, roads, and core area buildings based on BIM;

[0043] Create 3D vector primitives based on the oblique photography 3D model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity;

[0044] A three-dimensional model monomer with fine texture and external structure is produced by reconstructing the monomers; and the two-dimensional vector primitives, the three-dimensional vector primitives and the three-dimensional model monomers are integrated to obtain a three-dimensional model of the real city scene.

[0045] The real-life three-dimensional scene model of the city constructed by the present invention can be expanded through associated attributes to achieve rapid measurement, query and positioning. Specifically, in response to the problem of data transmission and display delay caused by frequent user interaction, the present invention judges the scope of the target basic geographic entity determined by the interactive operation in response to detecting the existence of an interactive operation in the human-computer interaction interface of the BIM; when there are multiple consecutive interactive operations within the scope of the target basic geographic entity, the multiple consecutive interactive operations are determined as idempotent operations; responds to user needs based on the idempotent operation; in response to the problem of standardizing the processing process of multi-source heterogeneous data with different dimensional values, the present invention extracts two-dimensional vector primitives corresponding to water systems, roads, and core area buildings based on BIM for each basic geographic entity; produces three-dimensional vector primitives based on the oblique photography three-dimensional model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity; produces a three-dimensional model monomer with fine texture and external structure by reconstructing the monomer; and fuses the two-dimensional vector primitives, three-dimensional vector primitives and three-dimensional model monomers to obtain a real-life three-dimensional model of the city. The whole process digitizes the entire real city, realizes the digital expression of all elements of the city, and the dynamic three-dimensional presentation, and is based on the hierarchical standardization of LOD1.3, LOD2 and LOD3, which can avoid the performance bottleneck problem of data storage and transmission of multi-source heterogeneous data.

[0046] Further advantages of the present invention will be further reflected in detail in the specific embodiments section in conjunction with the drawings of the specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 This is a schematic diagram of the main process of a method for constructing a city real scene 3D model based on BIM according to an embodiment of the present invention.

[0049] Figure 2Schematic diagram of multi-source heterogeneous data fusion processing flow of the method for constructing a three-dimensional urban real scene model based on BIM according to the present invention

[0050] Figure 3 Schematic diagram showing the acquisition of a three-dimensional model of oblique photography

[0051] Figure 4 Schematic diagram showing the effect of modifying the oblique photography 3D model containing basic geographic entities

[0052] Figure 5 Schematic diagram showing the process of obtaining laser point cloud data

[0053] Figure 6 This is a schematic diagram of the functional modules of a construction system of a city real scene 3D model based on BIM according to an embodiment of the present invention.

[0054] Figure 7 Schematic diagram of an improved embodiment of human-computer interaction processing in the construction system of the city real scene three-dimensional model based on BIM of the present invention DETAILED DESCRIPTION

[0055] Here, exemplary embodiments will be described in detail, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments that are the same as the present application. Instead, they are only examples of devices and methods that are the same as some aspects of the present application as detailed in the attached claims.

[0056] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program with a predetermined function, and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories) or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0057] At the same time, in the specific implementation of this application, if user-related data is involved, when the embodiment of this application is applied to a specific product or technology, the user's permission or consent must be obtained, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0058] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0059] See also Figure 1 , Figure 1 A schematic diagram of the main process of a method for constructing a city real-scene three-dimensional model based on BIM according to an embodiment of the present invention is shown.

[0060] Figure 1 The method is jointly executed based on aerial photography equipment and ground equipment.

[0061] In a specific embodiment, the aerial photography device is a drone equipped with a laser radar, and the ground device is a movable ground photography device equipped with a wireless communication module.

[0062] More specifically, the method comprises the following steps: Figure 1 Step numbers S1-S4 are omitted):

[0063] S1: Obtain existing large-scale topographic map data of the city, and extract water systems, roads, and core area buildings as basic geographic entities based on BIM;

[0064] S2: Based on the constructed multiple basic geographic entities, multiple aerial photography sub-areas are determined, and each aerial photography sub-area is photographed by an aerial photography device to obtain an oblique photography 3D model corresponding to each aerial photography sub-area, wherein each oblique photography 3D model includes at least one basic geographic entity;

[0065] S3: performing model modification on the oblique photography 3D model to obtain an oblique photography real-scene 3D model;

[0066] S4: Obtain laser point cloud data corresponding to each basic geographic entity, fuse the oblique photography real-scene 3D model with the laser point cloud data, and obtain a real-scene 3D model of the city;

[0067] Wherein, at least one ground device is configured within the range of each basic geographic entity, and the plurality of aerial photography partitions are determined according to the connection serial number of the ground device, and the aerial photography device photographs each aerial photography partition in sequence based on the connection serial number.

[0068] Next, combine Figure 2 The specific implementation plans of the above steps S1-S4 are described in detail as follows.

[0069] S1: Obtain existing large-scale topographic map data of the city, and extract water systems, roads, and core area buildings as basic geographic entities based on BIM.

[0070] Taking the target city X as an example, before implementing the technical solution of this application, the existing basic control data, topographic map data, geographical conditions monitoring data, annual change survey data, list of trunk rivers and roads, and core (landmark) building drawings of City X can be obtained in accordance with regulations.

[0071] Basic control data: Real-time control benchmark service provided by JSCORS station, used for RTK image control measurement, based on the elevation conversion service provided by CORS center, used to convert the geodetic height of image control measurement results into 85 height;

[0072] Topographic map data: 1:500 and 1:2000 large-scale sub-map topographic maps, which are the original data for the production of basic geographic entity data, from which the vector ranges and some attributes of project buildings, water systems, and roads are extracted;

[0073] Geographical national conditions monitoring data: Provides the names, grades, types and other attributes of some unchanged roads and rivers. It also provides administrative division boundaries at all levels to assist in the naming of basic geographic entity coding zones;

[0074] Annual change survey data: extract some road and railway surfaces, and summarize them into basic geographic entity data after current comparison and updating.

[0075] List of backbone rivers: if the entity type field corresponds to the category, the attributes such as the starting and ending points, functions, and grades can be directly obtained;

[0076] Core (iconic) building drawings and materials: Provide core (iconic) building floor plans, elevations, construction drawings and other materials to assist in building component-level 3D models and provide relevant information such as size and location.

[0077] Of course, the original data also needs to be preprocessed as follows:

[0078] Integration processing: Vector graphics are not standardized and need to be standardized and unified, including format conversion, coordinate conversion (conversion of different coordinate systems to the 2000 National Geodetic Coordinate System), and map edge connection (connection and merging of discrete lines and surface elements of incomplete features at the boundary).

[0079] Mapping transformation: data mapping (geometry mapping, attribute mapping).

[0080] Semantic acquisition:

[0081] 1. Enrich and extend attributes: give priority to using attributes and semantic information that can be directly extracted from large-scale topographic maps, and assign values ​​to basic geographic entity elements based on spatial position relationships; the insufficient parts can be extracted internally through Mesh 3D models, point cloud data and other collected relevant information. The attributes extracted from topographic map data include: the number of floors and structure of houses, road names, etc., and the attributes that can be extracted from Mesh 3D models and point cloud data include: the number of floors and structure of houses, etc.

[0082] 2. House merging: Merge multiple graphics elements of different types that belong to the same basic geographical entity of a house. Merge the houses that can be determined to be the same building by internal work, and do not merge those that cannot be determined.

[0083] 3. Complete basic attributes: Fill in the geographic entity name and entity classification code attributes according to the "Mapping Relationship Table between Basic Geographic Information Elements and Basic Geographic Entities"; fill in the entity coding attributes according to the coding rules in the "Description of the Classification and Coding Rules of Basic Geographic Entities in XX Province (Trial Version)"; fill in the graphic type attributes according to the actual geometric type of the geographic entity.

[0084] Step S1 can use the existing large-scale topographic map data of the city to extract two-dimensional vector primitives (which can be stretched to LOD1.3 white model), attributes and semantics of water systems, roads, buildings (structures), etc., and construct basic geographic entities.

[0085] Next, step S2 determines multiple aerial photography subareas based on the constructed multiple basic geographic entities, uses aerial photography equipment to photograph each aerial photography subarea, and obtains an oblique photography three-dimensional model corresponding to each aerial photography subarea, each of the oblique photography three-dimensional models containing at least one basic geographic entity;

[0086] Specifically, based on the oblique photography 3D model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity, a 3D vector primitive is produced; the 3D vector primitive is a LOD2 level white model with a top structure.

[0087] At this point, metadata production includes geographic scene metadata and basic geographic entity metadata.

[0088] Geographic scene metadata includes three types of metadata: 1. Oblique photography 3D model, 2. True orthogonal image, 3. Laser point cloud data;

[0089] Basic geographic entities are divided into two types of metadata: 1. Basic geographic entities in the form of two-dimensional vector primitives; 2. Geographic entities in the form of three-dimensional vector primitives. Basic geographic entity metadata files are recorded based on basic geographic entity functional themes, stored in a spreadsheet format, and in CSV format.

[0090] Geographic scene metadata and basic geographic entity metadata are produced with reference to the technical design document.

[0091] On this basis, step S3 modifies the oblique photography 3D model to obtain an oblique photography real scene 3D model;

[0092] Figure 3 The schematic diagram of obtaining the oblique photography 3D model is shown. Based on the original photos, camera files, POS, image control point results, etc. collected by the drone, the overall adjustment of the regional network is performed to obtain the oblique photography 3D model to be processed.

[0093] Figure 4 A schematic diagram showing the effect of modifying the oblique photography 3D model containing basic geographic entities.

[0094] Figure 4 The upper middle figure shows the effect of modifying the oblique photography 3D model of a water system as a basic geographic entity. Figure 4 The lower middle figure shows a schematic diagram of the effect of model modification on an oblique photography 3D model of a core area building, which is a basic geographic entity.

[0095] Based on the modified oblique photography model that meets the requirements, vertical projection transformation is performed, sampling interval is set, and light and color are evenly distributed; the results are submitted as a whole image without being divided into frames.

[0096] Next, step S4 obtains the laser point cloud data corresponding to each basic geographic entity, fuses the oblique photography real-scene 3D model with the laser point cloud data, and obtains the real-scene 3D model of the city;

[0097] Specifically, step S4 includes Figure 2 The steps S401-S404 ( Figure 2 Step numbers S401-S404 are omitted):

[0098] S401: For each basic geographic entity, extract the two-dimensional vector primitives corresponding to the water system, roads, and core area buildings based on BIM;

[0099] S402: Creating a three-dimensional vector primitive based on the oblique photography three-dimensional model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity;

[0100] S403: Producing a three-dimensional model monomer with fine texture and external structure by reconstructing the monomer;

[0101] S404: The two-dimensional vector primitives, the three-dimensional vector primitives and the three-dimensional model monomers are integrated to obtain a three-dimensional model of the real city scene.

[0102] The two-dimensional vector primitive can be stretched into a LOD1.3 level white model;

[0103] The three-dimensional vector primitive is a LOD2 level white model with a top structure;

[0104] The three-dimensional model monomer is a LOD3 level model monomer.

[0105] In the above embodiment, the step S4 of obtaining the laser point cloud data corresponding to each basic geographic entity specifically includes: performing image control measurement on each aerial photography partition by the drone equipped with the laser radar to obtain a point cloud data set; solving the point cloud data set, performing coordinate conversion and framing output, and obtaining the laser point cloud data.

[0106] Figure 5 A schematic diagram showing the process of acquiring laser point cloud data.

[0107] In a specific embodiment, the laser radar point cloud is obtained by a certain type of multi-rotor drone equipped with a micro laser radar device. The flight altitude is set to 150 meters, and the high-rise building area is additionally scanned according to the results. The scanning overlap is between 30% and 60%. The point cloud density exceeds the project requirement of 8 points per square meter; 2. The aerial photography partition is consistent with the oblique aerial photography. The absolute coordinate system is obtained through GPS + airborne POS. DJI Zhitu is used for solution processing, and globalmapper is used for coordinate conversion.

[0108] In a specific embodiment, the survey area is divided into 14 aerial photography operation areas according to the performance of aerial photography equipment, topography, building height and project promotion plan; the laser radar point cloud is obtained by DJI M300 equipped with DJI L1 micro laser radar. The flight altitude is 150 meters, and the high-rise building area is additionally scanned. The scanning overlap is between 30% and 60%. The point cloud density exceeds 8 points per square meter.

[0109] In addition to meeting relevant regulatory requirements and flight safety, the following factors also need to be considered:

[0110] 1. Route planning: Route planning is carried out based on the survey, flight safety, and image resolution requirements. 70%\27%\3%, 170m, 191m, 260m;

[0111] 2. Drone flight: 3. A total of 513 image control points were deployed in this project, and the points were evenly distributed inside the survey area, beyond the edge of the survey area, and appropriately encrypted in some areas with dense high-rise buildings.

[0112] After the above processing, the city real scene three-dimensional model can be formed.

[0113] At this time, the method further includes step S5: integrating the city real scene three-dimensional model into the BIM.

[0114] However, in actual applications, it is found that due to the increasing size of cities, the data volume of city-level real-life 3D models and some major public facilities has reached TB level, and frequent responses on the human-computer interaction interface will cause obvious jams and delays in data transmission, affecting the visualization effect and human-computer interaction experience. To solve this technical problem, the present invention is further improved as follows.

[0115] That is, after step S5, the method also includes step S6: in response to detecting the presence of an interactive operation in the human-computer interaction interface of the BIM, determining the target basic geographic entity range determined by the interactive operation; when there are multiple consecutive interactive operations within the target basic geographic entity range, determining the multiple consecutive interactive operations as idempotent operations; and responding to user needs based on the idempotent operation.

[0116] In this scenario, lag and delay are caused by the user's frequent clicks, which require the system to respond frequently in a short time.

[0117] Generally speaking, due to the huge amount of urban three-dimensional modeling data, when a user clicks on a basic geographic entity, he expects to quickly obtain a real-life three-dimensional image of the city within the scope of the basic geographic entity. However, due to various reasons such as data transmission, the response may not be met in a short time. At this time, the user's operation may be to repeatedly click on the basic geographic entity, expecting a faster response.

[0118] In the existing technology, for each click of the user, the system background will process it as a separate response event. If the user interacts N times in a short period of time (clicks on the same area N times, N>2), the system background will process it as N events, which further increases the background data transmission and processing pressure, and also increases the front-end detection pressure.

[0119] However, the inventors noticed that in the human-computer interaction of BIM, most of the N interactions of users in this scenario are for images within the area of ​​the same target basic geographic entity of interest, without the need for multiple transmissions or the need to transmit the entire modeling scene.

[0120] To this end, the improved embodiment further introduces the judgment of idempotent operations.

[0121] The so-called idempotent operation refers to multiple interaction events within a preset time period and / or a preset area, which are all treated as one interaction event by the system, that is, N and 1 idempotent. If an idempotent event occurs, it corresponds to an idempotent operation; the system only needs to respond to the user's needs based on the idempotent operation, without repeated responses.

[0122] In the above example, even if the user triggers multiple interactive operations, the system regards them as one processing if the idempotent operation conditions are met.

[0123] Specifically, the process is divided into the following three stages:

[0124] Phase 1: in response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, determining the scope of the target basic geographic entity determined by the interactive operation;

[0125] When the target basic geographic entity range includes only one basic geographic entity, or includes multiple basic geographic entities but the multiple associated basic geographic entities are actually associated entities as a whole, enter the second stage;

[0126] Here, multiple basic geographic entities are included, but the multiple basic geographic entities are actually as a whole associated entity, and can exist in multiple forms. For example, multiple basic geographic entities are loaded simultaneously each time;

[0127] Phase 2: when there are multiple consecutive interactive operations within the scope of the target basic geographic entity, the multiple consecutive interactive operations are determined as idempotent operations;

[0128] Phase 3: Responding to user needs based on the idempotent operation.

[0129] The above judgment process can be implemented based on the pseudo code of computer program language as follows:

[0130] Setting time thresholds , times threshold and the region size (area) threshold ;

[0131] When the target basic geographic entity range includes only one basic geographic entity, or includes multiple basic geographic entities but the multiple associated basic geographic entities are actually associated entities as a whole, obtain the visualized area size M of the target basic geographic entity range; the visualized area size M of the target basic geographic entity range is the area of ​​the area visible on the human-computer interaction interface when the basic geographic entity is visualized;

[0132] When setting the time threshold , detect that the number of consecutive interaction operations Num is greater than the number threshold , and the click positions corresponding to multiple interactive operations are all within the area size (area) threshold When the time is within , the multiple consecutive interaction operations are determined as idempotent operations.

[0133] The above improvements can significantly solve the problems of data transmission and display delays caused by frequent user interactions.

[0134] To achieve Figure 1 - Figure 5 The steps of the method embodiment are: Figure 6 A schematic diagram showing the functional module composition of a system for constructing a city real-scene three-dimensional model based on BIM according to an embodiment of the present invention.

[0135] exist Figure 6 In the figure, a construction system of a real-scene three-dimensional model of a city based on BIM is shown. The system includes an unmanned aerial vehicle (UAV) aerial photography device equipped with a laser radar and a movable ground photography device equipped with a wireless communication module. The movable ground photography device interacts with the UAV via wireless communication data instructions.

[0136] The BIM obtains existing large-scale topographic map data of the city, extracts water systems, roads, and core area buildings as basic geographic entities, and determines multiple aerial photography zones based on the constructed multiple basic geographic entities;

[0137] Assigning a plurality of numbered movable ground photographing devices to the plurality of aerial photography subareas, wherein the aerial photography devices sequentially photograph each aerial photography subarea based on the guidance of the numbered movable ground photographing devices, and obtaining an oblique photography three-dimensional model corresponding to each aerial photography subarea and laser point cloud data corresponding to each basic geographic entity;

[0138] The BIM fuses the oblique photography real-scene three-dimensional model with the laser point cloud data to obtain a real-scene three-dimensional model of the city;

[0139] Integrating the real-scene three-dimensional model of the city into the BIM;

[0140] In response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, a regional city real-scene three-dimensional model corresponding to at least one basic geographic entity corresponding to the interactive operation is displayed in the human-computer interaction interface.

[0141] Preferably, Figure 7 Schematic diagram of an improved embodiment of human-computer interaction processing in a construction system of a city real scene three-dimensional model based on BIM according to the present invention. Figure 7 In, the system further comprises an idempotent processing unit;

[0142] In response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, the idempotent processing unit determines a target basic geographic entity range determined by the interactive operation;

[0143] When there are multiple consecutive interactive operations within the target basic geographic entity range, the idempotent processing unit determines the multiple consecutive interactive operations as idempotent operations;

[0144] Respond to user demands based on the idempotent operation.

[0145] The BIM integrates the oblique photography real-scene 3D model with the laser point cloud data to obtain a real-scene 3D model of the city, specifically including:

[0146] For each basic geographic entity, extract the two-dimensional vector primitives corresponding to the water system, roads, and core area buildings based on BIM;

[0147] Create 3D vector primitives based on the oblique photography 3D model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity;

[0148] A three-dimensional model monomer with fine texture and external structure is produced by reconstructing the monomers; and the two-dimensional vector primitives, the three-dimensional vector primitives and the three-dimensional model monomers are integrated to obtain a three-dimensional model of the real city scene.

[0149] The real-life three-dimensional scene model of the city constructed by the present invention can be expanded through associated attributes to achieve rapid measurement, query and positioning. Specifically, in response to the problem of data transmission and display delay caused by frequent user interaction, the present invention judges the scope of the target basic geographic entity determined by the interactive operation in response to detecting the existence of an interactive operation in the human-computer interaction interface of the BIM; when there are multiple consecutive interactive operations within the scope of the target basic geographic entity, the multiple consecutive interactive operations are determined as idempotent operations; responds to user needs based on the idempotent operation; in response to the problem of standardizing the processing process of multi-source heterogeneous data with different dimensional values, the present invention extracts two-dimensional vector primitives corresponding to water systems, roads, and core area buildings based on BIM for each basic geographic entity; produces three-dimensional vector primitives based on the oblique photography three-dimensional model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity; produces a three-dimensional model monomer with fine texture and external structure by reconstructing the monomer; and fuses the two-dimensional vector primitives, three-dimensional vector primitives and three-dimensional model monomers to obtain a real-life three-dimensional model of the city. The whole process digitizes the entire real city, realizes the digital expression of all elements of the city, and the dynamic three-dimensional presentation, and is based on the hierarchical standardization of LOD1.3, LOD2 and LOD3, which can avoid the performance bottleneck problem of data storage and transmission of multi-source heterogeneous data.

[0150] The technical solution of the present invention has been applied to the construction project of real-life 3D scene model in some areas of a province and has passed the acceptance smoothly. In addition to the advantages of the embodiments described above, the acceptance and appraisal results of the present invention also have the following characteristics:

[0151] 1. High resolution, high degree of fusion and matching of multiple models, high degree of completeness of overall scene construction, and unified and complete data.

[0152] The products of this project include inclined mesh models, flattened inclined mesh models, LOD2 white models, reconstructed monomer models, component three-dimensional models and other model results, which are integrated into the background and cloud database of the BIM and have different production methods. The LOD2 white model, reconstructed monomer model and component three-dimensional model can be combined into a complete set of building model results and used separately. After being associated with the building attribute information, management and query applications can be realized; the flattened inclined mesh model, reconstructed monomer model and component three-dimensional model are integrated into a complete set of geographic scenes, which can be used as the digital foundation of the city-level spatiotemporal big data platform.

[0153] 2. BIM configures production tools and quality inspection tools to improve the production efficiency and quality of two-dimensional basic geographic entities.

[0154] The production of two-dimensional basic geographic entities is based on the conversion of topographic map data, which involves a large amount of two-dimensional vector data processing and attribute information sorting. After analyzing the technical requirements, we organized and configured data templates and developed more than a dozen different auxiliary production tools, such as: automatic extraction of attribute information, automatic collection of elevation values, automatic generation of outer surface, automatic conversion of feature types, etc. For the inspection of the results of two-dimensional basic geographic entities, such as two-dimensional vector graphics inspection and attribute information inspection, more than ten different auxiliary inspection tools have been developed, which can conveniently check the consistency of contour surface and layer surface, check the conformity of layer number and elevation, and check the correctness of attribute information such as elevation, number of layers, structure, etc. With the help of auxiliary production tools and inspection tools, the production efficiency is greatly improved, the omission problem of manual inspection is avoided to the greatest extent, and the quality of the final result data is improved.

[0155] 3. The reconstructed three-dimensional models of models and components are finely made, with good texture effects and wide application in the later stage.

[0156] 4. The single model reconstructed in key areas has high precision, high texture restoration, and good integration with surrounding scenes. In the later stage, it can provide basic data support for urban publicity and asset management. The indoor scene of the component three-dimensional model has high restoration and rich texture. The component facilities produced in a single form can expand related information and realize management, query and other applications. The perfect integration of indoor and outdoor model scenes can realize seamless roaming display of indoor and outdoor scenes, increasing the user experience.

[0157] The present invention provides multiple embodiments, each of which can constitute an independent technical solution and may contribute to the prior art and solve corresponding technical problems. However, it should be pointed out that different embodiments can be combined with each other without violating logic; at the same time, each embodiment can solve at least one technical problem, but it is not required that each individual embodiment solves multiple or all technical problems.

[0158] For other technologies, principles, algorithms or models not elaborated in detail in this application, please refer to the prior art.

[0159] The foregoing has shown and described the method embodiments and system of the present invention, but it is understandable to those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a real-scene three-dimensional model of a city based on BIM, the method is jointly executed by aerial photography equipment and ground equipment, and is characterized in that: The method comprises the following steps: Step S1: Obtain existing large-scale topographic map data of the city, and extract water systems, roads, and core area buildings as basic geographic entities based on BIM; Step S2: based on the constructed multiple basic geographic entities, determine multiple aerial photography subareas, use aerial photography equipment to shoot each aerial photography subarea, and obtain an oblique photography three-dimensional model corresponding to each aerial photography subarea, each of the oblique photography three-dimensional models containing at least one basic geographic entity; Step S3: performing model modification on the oblique photography 3D model to obtain an oblique photography real-scene 3D model; Based on the original photos, camera files, POS, and image control point results collected by drones, the overall adjustment of the regional network is carried out to obtain the oblique photography 3D model to be processed; Based on the modified oblique photography model that meets the requirements, vertical projection transformation is performed, sampling intervals are set, and light and color are evenly distributed; the results are submitted as a whole image without segmentation; Step S4: obtaining laser point cloud data corresponding to each basic geographic entity, fusing the oblique photography real-scene 3D model with the laser point cloud data, and obtaining a real-scene 3D model of the city; Specifically, step S4 includes steps S401-S404: S401: For each basic geographic entity, extract the two-dimensional vector primitives corresponding to the water system, roads, and core area buildings based on BIM; S402: Creating a three-dimensional vector primitive based on the oblique photography three-dimensional model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity; S403: Producing a three-dimensional model monomer with fine texture and external structure by reconstructing the monomer; S404: fusing the two-dimensional vector primitives, the three-dimensional vector primitives and the three-dimensional model monomers to obtain a three-dimensional model of a real city scene; The two-dimensional vector primitive can be stretched into a LOD1.3 level white model; The three-dimensional vector primitive is a LOD2 level white model with a top structure; The three-dimensional model monomer is a LOD3 level model monomer; Step S5: Integrate the city real scene three-dimensional model into the BIM; Step S6: in response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, determining the target basic geographic entity range determined by the interactive operation; when there are multiple consecutive interactive operations within the target basic geographic entity range, determining the multiple consecutive interactive operations as idempotent operations; responding to user needs based on the idempotent operation; Wherein, at least one ground device is configured within the range of each basic geographic entity, and the plurality of aerial photography partitions are determined according to the connection serial number of the ground device, and the aerial photography device photographs each aerial photography partition in sequence based on the connection serial number.

2. The method for constructing a three-dimensional model of a real city based on BIM according to claim 1, characterized in that: The aerial photography equipment is a drone equipped with a laser radar, and the ground equipment is a movable ground photography equipment equipped with a wireless communication module.

3. The method for constructing a three-dimensional model of a real city based on BIM according to claim 1, characterized in that: The step of obtaining the laser point cloud data corresponding to each basic geographic entity specifically includes: A point cloud data set is obtained by performing image control measurement on each aerial photography partition using a UAV equipped with a laser radar; The laser point cloud data is obtained by solving the point cloud data set, performing coordinate transformation and framing output.

4. A system for constructing a real-scene three-dimensional model of a city based on BIM, the system comprising an unmanned aerial photography device equipped with a laser radar and a movable ground photography device equipped with a wireless communication module, wherein the movable ground photography device and the unmanned aerial vehicle perform wireless communication data instruction interaction; Features: The BIM obtains existing large-scale topographic map data of the city, extracts water systems, roads, and core area buildings as basic geographic entities, and determines multiple aerial photography zones based on the constructed multiple basic geographic entities; Assigning a plurality of numbered movable ground photographing devices to the plurality of aerial photography subareas, wherein the aerial photography devices sequentially photograph each aerial photography subarea based on the guidance of the numbered movable ground photographing devices, and obtaining an oblique photography three-dimensional model corresponding to each aerial photography subarea and laser point cloud data corresponding to each basic geographic entity; The BIM integrates the oblique photography real-scene 3D model with the laser point cloud data to obtain the real-scene 3D model of the city; based on the original photos, camera files, POS, and image control point results collected by the drone, the overall adjustment of the regional network is performed to obtain the oblique photography 3D model to be processed; Based on the modified oblique photography model that meets the requirements, vertical projection transformation is performed, sampling intervals are set, and light and color are evenly distributed; the results are submitted as a whole image without segmentation; Specifically, step S4 includes steps S401-S404: S401: For each basic geographic entity, extract the two-dimensional vector primitives corresponding to the water system, roads, and core area buildings based on BIM; S402: Creating a three-dimensional vector primitive based on the oblique photography three-dimensional model corresponding to each aerial photography partition and the laser point cloud data corresponding to each basic geographic entity; S403: Producing a three-dimensional model monomer with fine texture and external structure by reconstructing the monomer; S404: fusing the two-dimensional vector primitives, the three-dimensional vector primitives and the three-dimensional model monomers to obtain a three-dimensional model of a real city scene; The two-dimensional vector primitive can be stretched into a LOD1.3 level white model; The three-dimensional vector primitive is a LOD2 level white model with a top structure; The three-dimensional model monomer is a LOD3 level model monomer; After the above processing, the real-scene three-dimensional model of the city is formed; Integrate the real-scene three-dimensional model of the city into the BIM; in response to detecting that there is an interactive operation in the human-computer interaction interface of the BIM, determine the target basic geographic entity range determined by the interactive operation; when there are multiple consecutive interactive operations within the target basic geographic entity range, determine the multiple consecutive interactive operations as idempotent operations; respond to user needs based on the idempotent operation; Wherein, at least one ground device is configured within the range of each basic geographic entity, and the plurality of aerial photography partitions are determined according to the connection serial number of the ground device, and the aerial photography device photographs each aerial photography partition in sequence based on the connection serial number.

5. A computer-readable medium having computer program instructions stored thereon, wherein the computer program instructions can be executed by a processor to implement a method for constructing a BIM-based urban real-scene three-dimensional model as described in any one of claims 1 to 3.

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