A three-dimensional model construction method and related device
By collecting external image data and internal point cloud data in paleogeological surveying and fusion calculation, a high-precision and coherent three-dimensional model is constructed, which solves the problems of incomplete terrain data and insufficient accuracy in traditional technology. It is suitable for Large-scale paleontological geological surveying and mapping work.
Patent Information
- Application Number
- CN202410943439.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2044-07-15
AI Technical Summary
In paleontological geological surveying, traditional tilt photography three-dimensional imaging technology cannot obtain complete terrain data, resulting in large position errors of the three-dimensional model and cannot meet the high-precision requirements. At the same time, although laser scanning point cloud reconstruction is accurate, it is not intuitive and accurate. Moreover, the data collection cycle is long, making it difficult to apply to large-scale work.
By determining the external and internal reconstruction areas in the target reconstruction area, external image data and internal point cloud data are collected, and fusion calculations are performed based on the geodetic coordinate system, reference coordinate system and point cloud coordinate system to build the target three-dimensional model and use the drone to Obtain high-precision coordinates and establish an integrated target three-dimensional model.
It realizes a three-dimensional model construction with high accuracy, consistency and integrity, which can fully describe the characteristics and information inside and outside the target reconstruction area, and improves the efficiency and accuracy of paleontological surveying and mapping.
Smart Images
Figure CN118485792B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of data processing, and specifically to a three-dimensional model construction method and related devices. Background Art
[0002] In paleontological geological mapping, it is necessary to collect topographic and geological features at various locations within a specific area, and to study the history of the earth and the process of biological evolution by analyzing the geological features and data such as paleontological fossils contained in the specific area.
[0003] In the related art, large-area surface data within the collection area is usually collected through oblique photography three-dimensional imaging technology, and a three-dimensional model corresponding to the area is generated based on the collected image data. However, the data in the images obtained by oblique photography is not comprehensive enough, and the complete terrain data corresponding to the collection area cannot be obtained, and thus a complete three-dimensional model of the area cannot be generated. Summary of the invention
[0004] In view of this, the first aspect of the present application provides a three-dimensional model construction method, the method comprising:
[0005] determining an outer reconstruction region and an inner reconstruction region in a target reconstruction region;
[0006] Acquire image data corresponding to the external reconstruction area, and determine reference coordinates corresponding to each external control point in the external reconstruction area; the reference coordinates are coordinate values of the external control point in a reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes geodetic coordinates of each external control point in a geodetic coordinate system;
[0007] Collecting point cloud data corresponding to the internal reconstruction area, and determining reference coordinates corresponding to each internal control point in the internal reconstruction area; the collection range of the point cloud data covers all internal control points in the internal reconstruction area, and the point cloud data includes point cloud coordinates of each internal control point in a point cloud coordinate system;
[0008] According to the earth coordinate system, the reference coordinate system and the point cloud coordinate system, a target coordinate system is determined; and according to the first transformation relationship, the second transformation relationship and the third transformation relationship, the image data and the point cloud data are fused and calculated in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area; wherein the first transformation relationship is the coordinate transformation relationship between the earth coordinate system and the target coordinate system; the second transformation relationship is the coordinate transformation relationship between the reference coordinate system and the target coordinate system; and the third transformation relationship is the coordinate transformation relationship between the point cloud coordinate system and the target coordinate system.
[0009] Optionally, determining the reference coordinates corresponding to each internal control point in the internal reconstruction area includes:
[0010] Determine an overlapping area between the external reconstruction area and the internal reconstruction area, and determine reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one;
[0011] The reference coordinates corresponding to each of the internal control points in the internal reconstruction area are determined according to the reference coordinates corresponding to each of the external control points.
[0012] Optionally, performing fusion calculation on the image data and the point cloud data in the target coordinate system according to the first conversion relationship, the second conversion relationship and the third conversion relationship to construct a target three-dimensional model corresponding to the target reconstruction area includes:
[0013] Performing aerial triangulation according to the image data to obtain an external preview model, using the reference coordinates of the external control points to perform spatial constraints on the external preview model, and determining the corresponding relationship between each of the external control points and the external preview model; converting the external preview model to the target coordinate system according to the first conversion relationship to obtain a target external model;
[0014] splicing the point cloud data to obtain an internal preview model; and transforming the internal preview model into the target coordinate system according to the third transformation relationship to obtain a target internal model;
[0015] The target internal model is fused with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area.
[0016] Optionally, the target coordinate system is the reference coordinate system; and fusing the target internal model with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area includes:
[0017] Coloring the target internal model based on the point cloud data;
[0018] Using the image data, coloring the target external model according to the resolution of the reference coordinate system;
[0019] According to the correspondence between the external control points and the internal control points in the overlapping area, the colored target internal model and the colored target external model are fused to generate the target three-dimensional model.
[0020] Optionally, the acquiring of image data corresponding to the external reconstruction area includes:
[0021] Controlling the UAV to obtain an orthophoto of the external reconstruction area at a vertical angle, and obtaining elevation data of the external reconstruction area;
[0022] According to the elevation data, the UAV is controlled to perform oblique photography of the external reconstruction area in a real-time terrain imitation flight mode to obtain image data of the external reconstruction area.
[0023] Optionally, the reference coordinate system is established in the following manner:
[0024] The reference coordinate system is established based on at least three basic control points in the target reconstruction area; wherein the basic control points include an initial control point, the basic control points do not belong to the same straight line, and the height difference between the basic control points and the maximum height difference of the target reconstruction area is greater than or equal to a preset ratio threshold.
[0025] A second aspect of the present application provides a three-dimensional model construction device, the device comprising:
[0026] The region determination unit is used to: determine an external reconstruction region and an internal reconstruction region in a target reconstruction region;
[0027] The external acquisition unit is used to: acquire image data corresponding to the external reconstruction area, and determine the reference coordinates corresponding to each external control point in the external reconstruction area; the reference coordinates are the coordinate values of the external control point in the reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes the geodetic coordinates of each external control point in the geodetic coordinate system;
[0028] An internal acquisition unit is used to: acquire point cloud data corresponding to the internal reconstruction area, and determine the reference coordinates corresponding to each internal control point in the internal reconstruction area; the acquisition range of the point cloud data covers all internal control points in the internal reconstruction area, and the point cloud data includes the point cloud coordinates of each internal control point in the point cloud coordinate system;
[0029] A model construction unit is used to: determine a target coordinate system according to the earth coordinate system, the reference coordinate system and the point cloud coordinate system; and to fuse the image data and the point cloud data in the target coordinate system according to a first transformation relationship, a second transformation relationship and a third transformation relationship, so as to construct a target three-dimensional model corresponding to the target reconstruction area; wherein the first transformation relationship is a coordinate transformation relationship between the earth coordinate system and the target coordinate system; the second transformation relationship is a coordinate transformation relationship between the reference coordinate system and the target coordinate system; and the third transformation relationship is a coordinate transformation relationship between the point cloud coordinate system and the target coordinate system.
[0030] Optionally, the internal acquisition unit is specifically used for:
[0031] Determine an overlapping area between the external reconstruction area and the internal reconstruction area, and determine reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one;
[0032] The reference coordinates corresponding to each of the internal control points in the internal reconstruction area are determined according to the reference coordinates corresponding to each of the external control points.
[0033] A third aspect of the present application provides a three-dimensional model construction device, the device comprising: a memory and a processor;
[0034] The memory is used to store instructions;
[0035] The processor is used to execute the instructions in the memory to perform the method described in the first aspect.
[0036] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer storage medium stores program codes or instructions. When the program codes or instructions are executed on a computer, the computer executes the method described in the first aspect above.
[0037] It can be seen from the above technical solutions that this application has the following advantages:
[0038] The present application provides a three-dimensional model construction method and related devices. First, an external reconstruction area and an internal reconstruction area in a target reconstruction area are determined. Secondly, image data corresponding to the external reconstruction area is collected; and reference coordinates corresponding to each external control point in the external reconstruction area are determined. Next, point cloud data corresponding to the internal reconstruction area is collected; and reference coordinates corresponding to each internal control point in the internal reconstruction area are determined. Then, based on the geodetic coordinate system, the reference coordinate system and the point cloud coordinate system, a target coordinate system is determined; and based on the first conversion relationship, the second conversion relationship and the third conversion relationship, the image data and the point cloud data are fused and calculated in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area. It can be seen that different data collection methods are adopted for the internal reconstruction area and the external reconstruction area in the target reconstruction area, image data is collected in the external reconstruction data, point cloud data is collected in the internal reconstruction area, and reference coordinates corresponding to each control point are collected in both the internal reconstruction area and the external reconstruction area, so that the internal reconstruction area and the external reconstruction area can determine the correspondence between the internal and external control points through the same reference coordinate system, and based on this correspondence, the internal reconstruction area and the external reconstruction area are connected to form an integrated target three-dimensional model. Compared with using the three-dimensional model corresponding to the external reconstruction area and the three-dimensional model corresponding to the internal reconstruction area respectively, the integrated target three-dimensional model has integrity and coherence, and can fully describe all features and information collected inside and outside the target reconstruction area. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 A method flow chart of a three-dimensional model construction method provided in an embodiment of the present application;
[0040] Figure 2 A schematic diagram of the internal model of a target after coloring provided in an embodiment of the present application;
[0041] Figure 3 A schematic diagram of the position uncertainty data distribution of the target external model provided in the embodiment of the present application;
[0042] Figure 4 A schematic diagram of the position uncertainty data distribution of a target three-dimensional model provided in an embodiment of the present application;
[0043] Figure 5 A schematic diagram of scene resolution data distribution of a target external model provided in an embodiment of the present application;
[0044] Figure 6 A schematic diagram of scene resolution data distribution of a target three-dimensional model provided in an embodiment of the present application;
[0045] Figure 7 A schematic diagram of the structure of a three-dimensional model building device provided in an embodiment of the present application. DETAILED DESCRIPTION
[0046] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.
[0047] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.
[0048] It should be noted that the concepts such as "first" and "second" mentioned in this application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.
[0049] It should be noted that the modifications of "one" and "plurality" mentioned in the present application are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".
[0050] In paleontological geological mapping, it is necessary to establish a three-dimensional model of the reconstruction area. However, generally speaking, conventional oblique photography methods cannot obtain surface data of all areas within the reconstruction area. For example, pits, caves, tunnels and other areas will have collection blind spots. However, in such collection blind spots, there is often important paleontological characteristic information.
[0051] Take a newly discovered site in a certain area as an example. The site is located in a natural cave on a cliff, and cultural relics are distributed around the cave wall and in sedimentary pits. In archaeological surveys, there are extremely high precision requirements for the location coordinate information of cultural relics and remains, which are usually controlled within the millimeter error range. Traditional oblique photography 3D imaging technology cannot meet this precision requirement due to its inherent limitations. Although the point cloud reconstruction method of laser scanning can provide high-precision data, it is not intuitive and accurate enough when expressing the positional relationship between the core area and the overall large area. In addition, when the data collected by oblique photography is used to generate a 3D model, due to the constraints of the technical conditions of the data acquisition equipment itself, the position error of the 3D model obtained at this time is usually a centimeter error, which cannot meet the research needs. When point cloud data is collected by a stand-mounted laser scanner and a 3D model is constructed based on the point cloud data, although the position error of the 3D model obtained at this time can be controlled within the millimeter range, which can meet the research needs, the acquisition cycle of point cloud data collected by laser scanners is longer and the data volume is larger, which is not convenient for carrying out operations in a large range of reconstruction areas, and it cannot be applied to large-scale paleontological geological mapping work.
[0052] To this end, the present application provides a three-dimensional model construction method, first, determine the external reconstruction area and the internal reconstruction area in the target reconstruction area. Secondly, collect the image data corresponding to the external reconstruction area, and determine the reference coordinates corresponding to each external control point in the external reconstruction area. Next, collect the point cloud data corresponding to the internal reconstruction area, and determine the reference coordinates corresponding to each internal control point in the internal reconstruction area. Then, based on the geodetic coordinate system, the reference coordinate system and the point cloud coordinate system, determine the target coordinate system; and based on the first transformation relationship, the second transformation relationship and the third transformation relationship, perform fusion calculation on the image data and the point cloud data in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area. It can be seen that different data collection methods are adopted for the internal reconstruction area and the external reconstruction area in the target reconstruction area, image data is collected in the external reconstruction data, point cloud data is collected in the internal reconstruction area, and reference coordinates corresponding to each control point are collected in both the internal reconstruction area and the external reconstruction area, so that the internal reconstruction area and the external reconstruction area can determine the correspondence between the internal and external control points through the same reference coordinate system, and based on this correspondence, the internal reconstruction area and the external reconstruction area are connected to form an integrated target three-dimensional model corresponding to the target reconstruction area. Compared with using the three-dimensional model corresponding to the external reconstruction area and the three-dimensional model corresponding to the internal reconstruction area respectively, the integrated target three-dimensional model has integrity and coherence, and can fully describe all features and information collected inside and outside the target reconstruction area.
[0053] See also Figure 1 , Figure 1A method flow chart of a three-dimensional model construction method provided in an embodiment of the present application, the method specifically comprises the following steps:
[0054] Step 101: Determine an external reconstruction area and an internal reconstruction area in a target reconstruction area.
[0055] In the target reconstruction area that needs to be surveyed and mapped, in order to collect data comprehensively, it is necessary not only to collect large-area surface data, but also to collect data on terrain with irregular spatial structures such as pits, caves, tunnels, and their interiors. Therefore, in the embodiment of the present application, the target reconstruction area is divided into an external reconstruction area and an internal reconstruction area, and data is collected from the external reconstruction area and the internal reconstruction area in different ways to improve the comprehensiveness and accuracy of data collection in different areas. Among them, the internal reconstruction area is the area where the above-mentioned pits, caves, tunnels, etc. are blocked and it is difficult to obtain satellite signals for positioning.
[0056] It should be understood that when acquiring geodetic coordinates, the embodiments of the present application can use drones, real-time kinematic (RTK) carrier phase differential technology, etc. to receive real-time position information through satellite signals. The satellite signals used in the embodiments of the present application are obtained by any one or more of the Beidou Navigation Satellite System (BDS), the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS) and the Galileo satellite navigation system (GALILEO).
[0057] Step 102: Acquire image data corresponding to the external reconstruction area, and determine the reference coordinates corresponding to each external control point in the external reconstruction area.
[0058] The reference coordinates are coordinate values of the external control points in the reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes the geodetic coordinates of each external control point in the geodetic coordinate system.
[0059] In the surveying and mapping process, it is necessary to obtain image data corresponding to all terrain information in the target reconstruction area. The surveying and mapping personnel will set multiple external control points in the range corresponding to the external reconstruction area based on the satellite image of the target reconstruction area and the location of the field survey. The embodiment of the present application can collect the reference coordinates corresponding to each external control point through a total station. The reference coordinates are the coordinate values of the external control points in the reference coordinate system. The coordinates of all control points collected by the total station are the coordinate values in the reference coordinate system.
[0060] In one possible implementation, the reference coordinate system can be established as follows:
[0061] The reference coordinate system is established according to at least three basic control points in the target reconstruction area.
[0062] The basic control points include an initial control point, the basic control points do not belong to the same straight line, and the height difference between the basic control points and the maximum height difference of the target reconstruction area is greater than or equal to a preset ratio threshold.
[0063] Before the surveying and mapping work begins, it is first necessary to set at least three basic control points in an open position that is relatively centered in the target reconstruction area and where the satellite signal is stable, and one of the basic control points is the initial control point; generally speaking, the more basic control points are set in the target reconstruction area, the smaller the coordinate error in the reference coordinate system. During the entire surveying and mapping process, the basic control points serve as standard coordinate reference points in the reference coordinate system, and their positions are fixed and cannot be obstructed or damaged. In an embodiment of the present application, the basic control points can be set in an external reconstruction area in the target reconstruction area.
[0064] In order to ensure the accuracy of the target coordinate system, when setting the basic control points, these basic control points cannot be on the same straight line; and the ratio between the height difference between the basic control points and the maximum height difference of the target reconstruction area should not be less than 1:20. For example, when the difference between the highest point and the lowest point in the target reconstruction area is 100 meters, that is, the maximum height difference of the target reconstruction area is 100 meters, the height difference between the basic control points should not be less than 5 meters.
[0065] In the external reconstruction area, in addition to using a total station to collect the reference coordinates of each external control point, it is also necessary to collect image data corresponding to the external reconstruction area. The image data can be composed of multiple photographic images, and all photographic images corresponding to the image data include all external control points. In the embodiment of the present application, the acquisition equipment used to collect image data includes but is not limited to drones. In order to accurately determine the geodetic coordinates of each external control point in the external reconstruction area, the geodetic coordinates of each external control point are usually calculated on the ground by an RTK surveying instrument. Since the drone moves based on the satellite positioning signal it receives when collecting image data, when collecting image data through the drone, the collection position of the drone can be controlled according to the geodetic coordinates of each external control point to obtain the image data corresponding to the external reconstruction area. The image data finally obtained also includes the geodetic coordinates corresponding to all external control points.
[0066] Based on the geodetic coordinates corresponding to each external control point in the image data and the reference coordinates corresponding to each external control point collected by the total station, the conversion relationship between the geodetic coordinate system and the reference coordinate system can be determined, and then the coordinate conversion between the geodetic coordinates and the reference coordinates can be realized based on the conversion relationship.
[0067] Specifically, image data can be collected in the following ways:
[0068] Step 11: Control the drone to obtain an orthophoto of the external reconstruction area at a vertical angle, and obtain elevation data of the external reconstruction area;
[0069] Step 12: According to the elevation data, the UAV is controlled to perform oblique photography of the external reconstruction area in a terrain-simulating flight mode to obtain image data of the external reconstruction area; the acquisition range of the image data covers all external control points.
[0070] The drone is controlled to obtain the orthophoto corresponding to each position in the external reconstruction area at a vertical angle, and the elevation data of the external reconstruction area is determined based on the orthophoto; through the elevation data, the height information of each position in the external reconstruction area can be determined, and the drone can determine the flight height corresponding to each position in the lowered flight mode according to the height information. When the drone is working in the terrain-imitating flight mode, the external reconstruction area can be obliquely photographed at the same distance to obtain multiple oblique photography images, that is, the image data in the embodiment of the present application, and all the external control points are included in all the oblique photography images collected by the drone.
[0071] It can be seen that by collecting elevation data and performing oblique photography in a real-time terrain-simulating flight mode while maintaining the same distance from the ground, the accuracy of image data collection for different locations and terrains can be improved.
[0072] Step 103: collecting point cloud data corresponding to the internal reconstruction area, and determining reference coordinates corresponding to each internal control point in the internal reconstruction area.
[0073] In the internal reconstruction area, due to the weak and unstable satellite signal, it is impossible to collect the geodetic coordinates therein by using equipment such as drones, and generally speaking, there is often important paleontological information in the internal reconstruction area; therefore, the embodiment of the present application acquires the surface data information in the internal reconstruction area by collecting high-precision point cloud data in the internal reconstruction area. It should be understood that in the embodiment of the present application, the equipment used to collect point cloud data includes but is not limited to a laser scanner.
[0074] The acquisition range of the point cloud data covers all internal control points in the internal reconstruction area, that is, the acquired point cloud data includes point cloud data corresponding to all internal control points, and the point cloud data includes the point cloud coordinates of each internal control point in the point cloud coordinate system.
[0075] In addition to the point cloud data, in order to subsequently link the internal reconstruction area with the external reconstruction area, the corresponding data of the two can also correspond to the same coordinate system, namely the reference coordinate system. That is to say, in the internal reconstruction area, the reference coordinates of each internal control point in the reference coordinate system can be determined by the total station.
[0076] It should be noted that when collecting point cloud data in the internal reconstruction area, the specific collection method and the amount of collected data can be determined according to the surveying and mapping software in the actual test scenario and the size of the internal reconstruction area. In the embodiment of the present application, the arrangement of the internal control points can be determined according to the positions obtained by the test personnel in the field survey.
[0077] Specifically, the reference coordinates corresponding to each internal control point in the internal reconstruction area can be determined in the following manner:
[0078] Step 21: determining an overlapping area between the external reconstruction area and the internal reconstruction area, and determining reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one;
[0079] Step 22: Determine the reference coordinates corresponding to each of the internal control points in the internal reconstruction area according to the reference coordinates corresponding to each of the external control points.
[0080] Since in the embodiments of the present application, the basic control points used to establish the reference coordinate system are usually set at an open position where the satellite signal is stable, that is, the external reconstruction area, in order to introduce the reference coordinate system of the external reconstruction area into the internal reconstruction area for continued use, it is necessary to gradually introduce the reference coordinate system starting from the overlapping area between the external reconstruction area and the internal reconstruction area. For example, when the internal reconstruction area is a cave, the overlapping area can be the location of the cave entrance, where satellite signals can be received to determine the geodetic coordinates of each position, and the reference coordinate system inside the cave can be linked to the reference coordinate system outside the cave.
[0081] In the overlapping area, there are both external control points and internal control points, and each external control point corresponds to each internal control point one by one. Through the reference coordinate system established in the external reconstruction area, the total station can determine the reference coordinates corresponding to each external control point in the overlapping area, and then determine the reference coordinates corresponding to each internal control point based on the correspondence between each internal control point and each external control point. According to this method, when the acquisition position of the total station gradually moves toward the internal reconstruction area, the reference coordinates of other internal control points can also be gradually determined, that is, the introduction of the reference coordinate system is realized.
[0082] It should be noted that, in the embodiment of the present application, the one-to-one correspondence between the internal control points and the external control points in the overlapping area may be a coincidence relationship, that is, for a control point in the overlapping area, it is both an internal control point and an external control point.
[0083] By determining the positional relationship and reference coordinates between the external control points and the internal control points in the overlapping area, the purpose of introducing a reference coordinate system into the internal reconstruction area is achieved, thereby improving the accuracy of the reference coordinates of the internal control points and enhancing the continuity of the coordinates between the internal and external control points.
[0084] Step 104: Determine the target coordinate system according to the geodetic coordinate system, the reference coordinate system and the point cloud coordinate system; and perform fusion calculations on the image data and the point cloud data in the target coordinate system according to the first transformation relationship, the second transformation relationship and the third transformation relationship to construct a target three-dimensional model corresponding to the target reconstruction area.
[0085] Among them, the first transformation relationship is the coordinate transformation relationship between the geodetic coordinate system and the target coordinate system; the second transformation relationship is the coordinate transformation relationship between the reference coordinate system and the target coordinate system; the third transformation relationship is the coordinate transformation relationship between the point cloud coordinate system and the target coordinate system.
[0086] When establishing the target three-dimensional model corresponding to the target reconstruction area, it is first necessary to unify the coordinate system between the external reconstruction area and the internal reconstruction area, that is, the target coordinate system corresponding to the target three-dimensional model. One of the geodetic coordinate system and the reference coordinate system can be selected as the target coordinate system.
[0087] Generally speaking, different target coordinate systems can be determined according to different display requirements of the target three-dimensional model. When the target three-dimensional model is mainly used to study the terrain features and paleontological remains of the target reconstruction area, the reference coordinate system can be used as the target coordinate system; at this time, according to the first conversion relationship between the geodetic coordinate system and the reference coordinate system, the reference coordinates corresponding to the geodetic coordinates of each pixel point in the image data can be determined; according to the third conversion relationship between the point cloud coordinate system and the reference coordinate system, the reference coordinates corresponding to the point cloud coordinates of each point in the point cloud data can be determined; in this way, both the image data and the point cloud data are displayed in the reference coordinate system, and fusion calculations are performed in the reference coordinate system, and finally the target three-dimensional model corresponding to the target reconstruction area in the embodiment of the present application is generated.
[0088] In the embodiment of the present application, since both the external control points and the internal control points are points whose specific positions can be determined in the reference coordinate system, the external reconstruction area can be connected to the internal reconstruction area through the reference coordinate system, thereby determining the connection between the external reconstruction area and the internal reconstruction area, laying the foundation for the fusion calculation of image data and point cloud data in the reference coordinate system.
[0089] When the target 3D model is used to display regional features, for example, to display the overall terrain features of area A, where part of the area is the target reconstruction area, it is necessary not only to generate a target 3D model corresponding to the target reconstruction area, but also to be able to combine the target 3D model with the 3D models of other areas in area A to form a complete 3D model corresponding to area A. In order to facilitate the fusion with other regional 3D models, it is generally necessary to determine the target coordinate system as the geodetic coordinate system; first, according to the conversion relationship between the point cloud coordinate system and the reference coordinate system, and the second conversion relationship between the reference coordinate system and the geodetic coordinate system, the third conversion relationship between the point cloud coordinate system and the geodetic coordinate system can be determined; then, according to the third conversion relationship, the point cloud coordinates of each point in the point cloud data are converted to the geodetic coordinate system; in this way, both the image data and the point cloud data are displayed in the geodetic coordinate system, and the fusion calculation is performed to finally generate the target 3D model corresponding to the target reconstruction area.
[0090] In a possible implementation, the target three-dimensional model may be created in the following manner:
[0091] Step 31: Perform aerial triangulation based on the image data to obtain an external preview model, use the reference coordinates of the external control points to spatially constrain the external preview model, and determine the corresponding relationship between each of the external control points and the external preview model; according to the first transformation relationship, transform the external preview model into the target coordinate system to obtain a target external model.
[0092] After obtaining the image data of the external reconstruction area, aerial triangulation is performed on the image data to obtain an external preview model corresponding to the external reconstruction area; specifically, real-scene 3D modeling software, such as ContextCapture, can be used to calculate and solve the oblique photographic images of the external reconstruction area to obtain the external preview model.
[0093] The reference coordinates corresponding to the external control points are used to spatially constrain the external preview model, thereby determining the correspondence between each external control point and the pixel point in the image data. Then, according to the first transformation relationship between the earth coordinate system and the target coordinate system, the external preview model is transformed into the target coordinate system to obtain the target external model corresponding to the external reconstruction area in the target coordinate system.
[0094] Step 32: stitching the point cloud data to obtain an internal preview model; and transforming the internal preview model into the target coordinate system according to the third transformation relationship to obtain a target internal model.
[0095] After obtaining the multi-site cloud data collected multiple times in the internal reconstruction area, firstly process and splice these point cloud data, and then package the spliced point cloud data and export them to obtain a point cloud file that can be recognized by third-party software, so as to obtain the overall point cloud data corresponding to the internal reconstruction area, that is, the internal preview model described in the embodiment of the present application. Specifically, the multi-site cloud data can be spliced by 3D laser scanning data processing software, such as faro scene.
[0096] Next, coordinate transformation is performed on the point cloud data in the internal preview model through a third transformation relationship between the point cloud coordinate system and the target coordinate system, thereby obtaining a target internal model corresponding to the internal preview model in the target coordinate system.
[0097] Step 33: Fusing the target internal model with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area.
[0098] After determining the target internal model and the target external model in the target coordinate system, spatial fusion calculation is performed on the target internal model and the target external model by means of control point constraints to determine the correspondence between the internal control points in the target internal model and the external control points in the target external model, so that the target internal model can be connected with the target external model based on the correspondence between the control points, thereby forming a complete target three-dimensional model corresponding to the target reconstruction area, thereby improving the integrity and coherence of the target three-dimensional model corresponding to the target reconstruction area.
[0099] As an embodiment, when the target coordinate system is a reference coordinate system, step 33 can be implemented as follows:
[0100] Step 41: Coloring the target internal model based on the point cloud data;
[0101] Step 42: Using the image data, coloring the target external model according to the resolution of the reference coordinate system;
[0102] Step 43: According to the correspondence between the external control points and the internal control points in the overlapping area, the colored target internal model and the colored target external model are merged to generate the target three-dimensional model.
[0103] In the embodiment of the present application, the target three-dimensional model finally generated is also a point cloud model. In the process of generating the target three-dimensional model, each point in it needs to be colored. For the target internal model, it can be colored directly based on its corresponding point cloud data. As for the target external model, the Context Capture software can be used to convert the target external model into a point cloud model; the texture-colored meshes in the target external model generated based on the image data are converted into connection points between each other. The connection points themselves already have colors and do not require secondary coloring.
[0104] Specifically, the target three-dimensional model generated after coloring the target internal model and the target external model includes various location points and their corresponding terrain information. Since the target three-dimensional model is a point cloud model, the location point is a point in the point cloud model. Each location point is associated with its corresponding paleontological feature image and the location information of the paleontological feature. When the location point is clicked in the target three-dimensional model, the display of the corresponding paleontological feature image and the location information of the paleontological feature can be triggered.
[0105] It should be noted that the control points used in the process of constructing the target three-dimensional model in the embodiment of the present application are only used to constrain the positional relationship between the points on the model surface, and the control points themselves do not have the function of being used to study and display information. In the target three-dimensional model finally generated, any position point on the model surface has coordinate information, which is used to study and display the target three-dimensional model.
[0106] See also Figure 2 , Figure 2 Schematic diagram of the internal model of the target after coloring provided in the embodiment of the present application. The internal model of the target is colored according to the true color corresponding to each point collected from the point cloud data. The internal model of the target after coloring includes both the terrain information in the internal core areas such as pits and caves that belong only to the internal reconstruction area, and the terrain information in the overlapping area that belongs to both the internal reconstruction area and the external reconstruction area.
[0107] After obtaining the colored target internal model and the colored target external model, the internal control points of the target internal model corresponding to the overlapping area between the internal reconstruction area and the external reconstruction area, and the external control points of the target external model corresponding to the overlapping area can be determined respectively; then, according to the correspondence between the internal control points and the external control points in the overlapping area, the colored target internal model and the colored target external model are fused to obtain the completed target three-dimensional model.
[0108] See also Figure 3 , Figure 3 A schematic diagram of the position uncertainty data distribution of the target external model provided in the embodiment of the present application. Figure 3 In the example, different colors are used to represent the position uncertainty (PositionUncertainty) corresponding to each connection point. In the embodiment of the present application, the position uncertainty can be used to reflect the error corresponding to each point in the model. When the value of the position uncertainty is smaller, it means that the error of the point is smaller and the information accuracy is higher. Figure 3 It can be seen that the target external model generated based on the oblique photography image mainly includes the position uncertainty corresponding to each point in the external reconstruction area and the overlapping area, and also includes a small amount of information in the internal reconstruction area. Among them, the key survey area in the external reconstruction area, that is, the external core area, contains relatively rich information points, and the position uncertainty corresponding to each point in the external core area is small, and the data error is small; overall, the position uncertainty of each point ranges from 0 to 0.67 meters, and there is less data about the overlapping area and the internal reconstruction area, especially in the key survey area in the internal reconstruction area, that is, the internal core area, the data collection is not sufficient, indicating that less information is obtained in the internal reconstruction area.
[0109] See also Figure 4 , Figure 4 A schematic diagram of the position uncertainty data distribution of the target three-dimensional model provided in an embodiment of the present application, wherein the position indicated by hole_1pro is the position of the overlapping area. Figure 4 Different colors are also used to represent the position uncertainty corresponding to each connection point. It can be seen that after the target external model is fused with the target internal model, the value range of the position uncertainty of each point in the target three-dimensional model is reduced to 0 to 0.14 meters, which not only reduces the position uncertainty of each point in the external core area, but also makes the error of each point in the internal core area approach 0. The overall data error of the target three-dimensional model is reduced and the model accuracy is improved. In addition, the external core area, overlapping area and internal core area in the target external model all contain rich information.
[0110] In the embodiment of the present application, when the resolution of the target coordinate system corresponding to the target external model is higher, the result accuracy corresponding to the colored target external model is higher, that is, the accuracy of the target three-dimensional model is higher. Generally speaking, the resolution and coordinate accuracy of the frame-mounted total station used to determine the reference coordinates and the laser scanner used to collect point cloud data are generally at the millimeter level, and when the corresponding image data of the external reconstruction area is collected by the drone, the unit area resolution and coordinate accuracy are generally at the centimeter level. The embodiment of the present application fuses the point cloud data and the image data through the reference coordinates, and the target external model is colored according to the coordinate accuracy of the reference coordinates. For example, when the calculation is not fused, an oblique photography image is broken up into 10 points according to the coordinate accuracy of the geodetic coordinate system to color the external preview model, and when the fusion calculation is performed, the external preview model is converted into the target external model in the reference coordinate system, and the coordinate accuracy is improved. Then, when it is colored again, the image of the corresponding position of the external preview model will be broken up into 50 points according to the coordinate accuracy of the reference coordinate system to color the target external model, and the model resolution performance is improved.
[0111] See also Figure 5 , Figure 5 A schematic diagram of the scene resolution data distribution of the target external model provided in the embodiment of the present application. In the embodiment of the present application, Figure 5 The scene resolution (Resolution) used in the scene is used to indicate the minimum image resolution of each position in the target reconstruction area. Different colors are used to represent the size of a pixel at the corresponding position. The unit is meter / pixel (m / px). The smaller the value, the smaller the unit area corresponding to each pixel, the richer the detailed information contained, and the better the resolution performance. Figure 5 The data distribution range of the scene resolution of each pixel point in the target external model is shown to be mainly 0 to 0.13 m / px, and the scene resolution value of each pixel point in the internal core area is larger, and the detail information is less.
[0112] See also Figure 6 , Figure 6 A schematic diagram of the scene resolution data distribution of the target 3D model provided in the embodiment of the present application, wherein the position indicated by hole_1pro is the position of the overlapping area. After the target internal model generated by the point cloud data is fused with the target external model, in the obtained target 3D model, the data distribution range of the scene resolution of each pixel point is mainly 0~0.02m / px. Compared with the target external model, the value of the scene resolution is significantly reduced, and the detail information in the target 3D model is richer; and the scene resolution of each point in the internal core area is close to 0, which further enriches the detail information in the internal core area.
[0113] It can be seen that the embodiment of the present application forms a complete target three-dimensional model by fusing and calculating the reference coordinates, point cloud data and image data, which not only improves the integrity and continuity between the inner and outer area models, but also improves the resolution and position accuracy of the target three-dimensional model, thereby improving the efficiency and accuracy of paleontological mapping.
[0114] Although operations are depicted in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order.Multitasking and parallel processing may be advantageous under certain circumstances.
[0115] It should be understood that the various steps described in the method implementation of the present application can be performed in different orders and / or performed in parallel. In addition, the method implementation may include additional steps and / or omit the steps shown. The scope of the present application is not limited in this respect.
[0116] See also Figure 7 , Figure 7 A schematic diagram of a three-dimensional model building device provided in an embodiment of the present application, the device comprising:
[0117] The region determination unit 201 is used to: determine an external reconstruction region and an internal reconstruction region in a target reconstruction region;
[0118] The external acquisition unit 202 is used to: acquire image data corresponding to the external reconstruction area; determine the reference coordinates corresponding to each external control point in the external reconstruction area; the reference coordinates are the coordinate values of the external control point in the reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes the geodetic coordinates of each external control point in the geodetic coordinate system;
[0119] The internal acquisition unit 203 is used to: acquire point cloud data corresponding to the internal reconstruction area; determine the reference coordinates corresponding to each internal control point in the internal reconstruction area; the acquisition range of the point cloud data covers all internal control points in the internal reconstruction area, and the point cloud data includes the point cloud coordinates of each internal control point in the point cloud coordinate system;
[0120] The model construction unit 204 is used to: determine the target coordinate system according to the earth coordinate system, the reference coordinate system and the point cloud coordinate system; and according to the first transformation relationship, the second transformation relationship and the third transformation relationship, fuse the image data and the point cloud data in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area; wherein the first transformation relationship is the coordinate transformation relationship between the earth coordinate system and the target coordinate system; the second transformation relationship is the coordinate transformation relationship between the reference coordinate system and the target coordinate system; and the third transformation relationship is the coordinate transformation relationship between the point cloud coordinate system and the target coordinate system.
[0121] Optionally, the internal collection unit 203 is specifically used for:
[0122] Determine an overlapping area between the external reconstruction area and the internal reconstruction area, and determine reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one;
[0123] The reference coordinates corresponding to each of the internal control points in the internal reconstruction area are determined according to the reference coordinates corresponding to each of the external control points.
[0124] Optionally, the model building unit 204 is specifically used for:
[0125] Performing aerial triangulation according to the image data to obtain an external preview model, using the reference coordinates of the external control points to perform spatial constraints on the external preview model, and determining the corresponding relationship between each of the external control points and the external preview model; converting the external preview model to the target coordinate system according to the first conversion relationship to obtain a target external model;
[0126] splicing the point cloud data to obtain an internal preview model; and transforming the internal preview model into the target coordinate system according to the third transformation relationship to obtain a target internal model;
[0127] The target internal model is fused with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area.
[0128] Optionally, the target coordinate system is the reference coordinate system; the model building unit 204 is specifically used for:
[0129] Coloring the target internal model based on the point cloud data;
[0130] Using the image data, coloring the target external model according to the resolution of the reference coordinate system;
[0131] According to the correspondence between the external control points and the internal control points in the overlapping area, the colored target internal model and the colored target external model are fused to generate the target three-dimensional model.
[0132] Optionally, the external acquisition unit 202 is specifically used for:
[0133] Controlling the UAV to obtain an orthophoto of the external reconstruction area at a vertical angle, and obtaining elevation data of the external reconstruction area;
[0134] According to the elevation data, the UAV is controlled to perform oblique photography of the external reconstruction area in a terrain-mimicking flight mode to obtain image data of the external reconstruction area; and the acquisition range of the image data covers all external control points.
[0135] Optionally, the device may further include a coordinate system establishing unit, configured to:
[0136] The reference coordinate system is established based on at least three basic control points in the target reconstruction area; wherein the basic control points include an initial control point, the basic control points do not belong to the same straight line, and the height difference between the basic control points and the maximum height difference of the target reconstruction area is greater than or equal to a preset ratio threshold.
[0137] The embodiment of the present application provides a three-dimensional model construction device, the device comprising: a memory and a processor;
[0138] The memory is used to store instructions;
[0139] The processor is used to execute the instructions in the memory and execute the method described in the above method embodiment.
[0140] An embodiment of the present application provides a computer-readable storage medium, which stores program codes or instructions. When the program codes or instructions are executed on a computer, the computer executes the method described in the above method embodiments.
[0141] The names of the messages or information exchanged between multiple devices in the embodiments of the present application are only used for illustrative purposes and are not used to limit the scope of these messages or information.
[0142] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.
[0143] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.
[0144] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A three-dimensional model construction method, characterized in that: The method comprises: determining an outer reconstruction region and an inner reconstruction region in a target reconstruction region; Acquire image data corresponding to the external reconstruction area, and determine reference coordinates corresponding to each external control point in the external reconstruction area; the reference coordinates are coordinate values of the external control point in a reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes geodetic coordinates of each external control point in a geodetic coordinate system; Collecting point cloud data corresponding to the internal reconstruction area, determining an overlapping area between the external reconstruction area and the internal reconstruction area, and determining reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one; determining reference coordinates corresponding to each of the internal control points in the internal reconstruction area according to the reference coordinates corresponding to each of the external control points; the collection range of the point cloud data covers all internal control points in the internal reconstruction area, and the point cloud data includes point cloud coordinates of each internal control point in a point cloud coordinate system; A target coordinate system is determined according to the geodetic coordinate system, the reference coordinate system and the point cloud coordinate system. When studying the topographic features and paleontological remains of the target reconstruction area, the reference coordinate system is determined as the target coordinate system. When displaying the regional features of the target reconstruction area, the geodetic coordinate system is determined as the target coordinate system. And according to the first conversion relationship, the second conversion relationship and the third conversion relationship, the image data and the point cloud data are fused and calculated in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area. The first conversion relationship is the coordinate conversion relationship between the geodetic coordinate system and the target coordinate system. The second conversion relationship is the coordinate conversion relationship between the reference coordinate system and the target coordinate system. The third conversion relationship is the coordinate conversion relationship between the point cloud coordinate system and the target coordinate system.
2. The method according to claim 1, characterized in that The method of performing fusion calculation on the image data and the point cloud data in the target coordinate system according to the first conversion relationship, the second conversion relationship and the third conversion relationship to construct a target three-dimensional model corresponding to the target reconstruction area includes: Performing aerial triangulation according to the image data to obtain an external preview model, using the reference coordinates of the external control points to perform spatial constraints on the external preview model, and determining the corresponding relationship between each of the external control points and the external preview model; converting the external preview model to the target coordinate system according to the first conversion relationship to obtain a target external model; splicing the point cloud data to obtain an internal preview model; and transforming the internal preview model into the target coordinate system according to the third transformation relationship to obtain a target internal model; The target internal model is fused with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area.
3. The method according to claim 2, characterized in that The target coordinate system is the reference coordinate system; The fusing the target internal model with the target external model to generate a target three-dimensional model corresponding to the target reconstruction area includes: Coloring the target internal model based on the point cloud data; Using the image data, coloring the target external model according to the resolution of the reference coordinate system; According to the correspondence between the external control points and the internal control points in the overlapping area, the colored target internal model and the colored target external model are fused to generate the target three-dimensional model.
4. The method according to claim 1, characterized in that The acquiring of image data corresponding to the external reconstruction area comprises: Controlling the UAV to obtain an orthophoto of the external reconstruction area at a vertical angle, and obtaining elevation data of the external reconstruction area; According to the elevation data, the UAV is controlled to perform oblique photography of the external reconstruction area in a real-time terrain imitation flight mode to obtain image data of the external reconstruction area.
5. The method according to any one of claims 1 to 4, characterized in that: The reference coordinate system is established as follows: The reference coordinate system is established based on at least three basic control points in the target reconstruction area; wherein the basic control points include an initial control point, the basic control points do not belong to the same straight line, and the height difference between the basic control points and the maximum height difference of the target reconstruction area is greater than or equal to a preset ratio threshold.
6. A three-dimensional model construction device, characterized in that: The device comprises: The region determination unit is used to: determine an external reconstruction region and an internal reconstruction region in a target reconstruction region; The external acquisition unit is used to: acquire image data corresponding to the external reconstruction area, and determine the reference coordinates corresponding to each external control point in the external reconstruction area; the reference coordinates are the coordinate values of the external control point in the reference coordinate system; the acquisition range of the image data covers all external control points, and the image data includes the geodetic coordinates of each external control point in the geodetic coordinate system; An internal acquisition unit is used to: acquire point cloud data corresponding to the internal reconstruction area, determine an overlapping area between the external reconstruction area and the internal reconstruction area, and determine reference coordinates corresponding to each of the external control points in the overlapping area; wherein the overlapping area includes a plurality of external control points and a plurality of internal control points, and the external control points correspond to the internal control points one by one; determine reference coordinates corresponding to each of the internal control points in the internal reconstruction area according to the reference coordinates corresponding to each of the external control points; the acquisition range of the point cloud data covers all internal control points in the internal reconstruction area, and the point cloud data includes point cloud coordinates of each internal control point in a point cloud coordinate system; A model building unit is used to: determine a target coordinate system according to the earth coordinate system, the reference coordinate system and the point cloud coordinate system; when studying the topographic features and paleontological remains of the target reconstruction area, determine the reference coordinate system as the target coordinate system; when displaying the regional features of the target reconstruction area, determine the earth coordinate system as the target coordinate system; and according to a first conversion relationship, a second conversion relationship and a third conversion relationship, perform fusion calculation on the image data and the point cloud data in the target coordinate system to construct a target three-dimensional model corresponding to the target reconstruction area; wherein the first conversion relationship is the coordinate conversion relationship between the earth coordinate system and the target coordinate system; the second conversion relationship is the coordinate conversion relationship between the reference coordinate system and the target coordinate system; and the third conversion relationship is the coordinate conversion relationship between the point cloud coordinate system and the target coordinate system.
7. A three-dimensional model building device, characterized in that: The device comprises: a memory and a processor; The memory is used to store instructions; The processor is used to execute the instructions in the memory and perform the method according to any one of claims 1 to 5.
8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program codes or instructions. When the program codes or instructions are executed on a computer, the computer is enabled to execute the method according to any one of claims 1 to 5.