A Data Acquisition Method Based on DSM and DOM
By using DSM and DOM-based data acquisition methods, combined with the ADS100 sensor and mathematical model, the problem of low data acquisition accuracy and efficiency in existing technologies has been solved, achieving high-precision ground feature acquisition and modeling data production, which is suitable for topographic mapping and geographic entity data acquisition.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING INSTITUTE OF SURVEYING AND MAPPING
- Filing Date
- 2023-11-08
- Publication Date
- 2026-05-26
AI Technical Summary
Existing data acquisition methods based on aerial imagery stereo acquisition and manual field surveying suffer from low accuracy, low efficiency, and high requirements for hardware and personnel skills, making it impossible to produce data on a large scale.
A data acquisition method based on DSM and DOM is adopted. Through data preprocessing, vector data acquisition, and projection correction algorithm, combined with ADS100 sensor and mathematical model, the accurate positioning of ground feature outlines and feature points is achieved. A projection correction algorithm is designed to solve the problem of discrepancies between the acquired ground feature outlines and the actual ones.
It improves the spatial location accuracy of data acquisition, enables basic scale topographic map surveying and mapping, and new basic surveying and mapping geographic entity acquisition and editing functions, and supports modeling data acquisition and editing. It meets the data acquisition accuracy requirements of 1:2000 topographic map and is suitable for geographic entity data acquisition and topographic map updates.
Smart Images
Figure CN117522981B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a data acquisition method, and more particularly to a data acquisition method based on DSM and DOM. Background Technology
[0002] With the continuous improvement of my country's scientific and technological level, the construction of current surveying and mapping geographic information systems requires the improvement of data acquisition working modes, the integration of geographic and surveying technologies, and the selection of new data acquisition technologies based on current development trends. Aerial photogrammetry-based stereo acquisition and manual field surveying are among the main methods of data acquisition in the surveying and mapping industry. Aerial photogrammetry-based stereo acquisition offers high accuracy and wide applicability, but it has special requirements in terms of hardware, software, and personnel skills. It generally requires specialized mapping workstations and stereoscopic glasses, and operators need professional training, resulting in low data acquisition efficiency. Manual field surveying is even less suitable for large-scale data production. Summary of the Invention
[0003] To address the shortcomings of the aforementioned technologies, this invention provides a data acquisition method based on DSM and DOM.
[0004] To solve the above technical problems, the technical solution adopted by the present invention is: a data acquisition method based on DSM and DOM, comprising the following acquisition steps:
[0005] S1. Data Preprocessing: Simultaneously load DSM data, DOM data, flight route data, and range line data, and perform coordinate transformation and organization on the loaded data;
[0006] S2. Vector Data Acquisition: Based on DOM data, vector data of ground feature outlines are acquired. Based on the OSGB format model generated from DSM data, elevation information of ground features is acquired.
[0007] S3. Projection correction through correction algorithm: The correction algorithm obtains the accurate correction amount, and the ground features with projection difference are translated perpendicular to the flight strip direction. The outline and feature points can be corrected back to obtain the true position of the ground feature outline.
[0008] Preferably, in step S1, the DSM data and the DOM data have the same coordinate system, and both are generated as model data in OSGB format.
[0009] The flight path data includes flight path elevation information and flight path number. The range line data is used as the range defined during image production to obtain the flight path number and flight path elevation information data corresponding to the collected vector data.
[0010] Preferably, data is acquired using the ADS100 sensor.
[0011] Preferably, in step S2, after collecting vector data of the outline of ground features in the DOM data image, the code of the ground feature entity whose elevation information needs to be collected is obtained, and then the elevation data is obtained by clicking on the OSGB data model of the DSM data.
[0012] Preferably, the collected elevation data includes ground elevation information and top outline information of ground features, with the top outline information of buildings being the building elevation; the association between ground feature attributes and ground elevation points, building elevation points, and collapsed roofs is identified through attribute fields.
[0013] Preferably, the elevation point data is associated with the ground features through the ground feature relationship field in the vector data ground feature attribute information, the ground elevation data is entered into the ground elevation field of the ground features, and the top outline information of the ground features, such as the building elevation for houses, is entered into the eaves elevation field.
[0014] Preferably, in step S3, the correction algorithm design specifically includes: establishing a mathematical model of a certain point of the ground feature; wherein, the ground feature collection point... O The coordinates are ( X 0, Y 0, Z 0), actual coordinates of ground features M ( X , Y , Z First node on the route A and end node B The coordinates are ( X 1, Y 1, Z 1) and ( X 2, Y 2, Z 2) Setting points O In a straight line AB The foot of the perpendicular is a point. N The coordinates are ( X n , Y n , Z n ),point N The coordinate calculation process is as follows:
[0015] First, calculate the vector:
[0016]
[0017] From the perpendicular relationship of vectors, we can obtain:
[0018]
[0019] point NIn a straight line AB Based on the collinearity of vectors, we can conclude that:
[0020]
[0021] Good points O In a straight line AB The foot coordinates of the perpendicular ( X n , Y n , Z n )for:
[0022]
[0023] Wherein, the correction parameter K is:
[0024]
[0025] Due to the corrected points M ( X , Y , Z ) on the straight line ON Above, therefore OM and MN Collinearity:
[0026]
[0027] After correction M The plane coordinates are:
[0028] .
[0029] Preferably, after loading the flight path data and the range line data, the correction algorithm determines the location of the vector feature based on the flight strip number in the range line data attribute field, obtains its corresponding flight altitude, and performs projection correction.
[0030] This invention discloses a data acquisition method based on DSM and DOM, which breaks the constraints of traditional acquisition methods. Through the inherent mathematical principles, a projection correction algorithm is designed to achieve projection correction, solving the drawbacks of inconsistencies between the collected feature outlines and the actual situation, as well as obvious collapse phenomena. This greatly improves the spatial location accuracy of the acquired data. It not only enables the basic scale topographic mapping function of solid lines and the new basic mapping geographic entity acquisition and editing function, but also enables the modeling data acquisition and editing function. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the technical route of the present invention.
[0032] Figure 2 The route data map is loaded.
[0033] Figure 3 This is a range line data plot for loading.
[0034] Figure 4 This is a diagram showing the relationship between image location and flight path.
[0035] Figure 5 This is a vector data display graph.
[0036] Figure 6 The collected vector data is displayed as a result graph.
[0037] Figure 7 This is a diagram showing the association between vector data and information.
[0038] Figure 8 This is a schematic diagram illustrating the pattern of image inversion.
[0039] Figure 9 This is a schematic diagram showing the relationship between spatial coordinates and flight paths.
[0040] Figure 10 for Figure 9 A schematic diagram of the projection relationship.
[0041] Figure 11 This is a comparison image of the outlines of ground features before and after projection correction. Detailed Implementation
[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0043] DOM data offers high planar accuracy and clear feature outlines, making it suitable for acquiring planar coordinate information or feature point coordinate information. DSM data offers high elevation accuracy, making it suitable for acquiring elevation information data of features. This invention innovatively combines the two to obtain three-dimensional coordinate information of features, achieving high-precision data acquisition.
[0044] In DOM data acquisition, the portion of ground features above the ground surface is affected by projection differences, resulting in planar offsets and spatial location accuracy errors. This leads to discrepancies between the acquired feature outlines and the actual features, with significant overhang. This invention analyzes the spatial relationships based on this characteristic and, through inherent mathematical principles, calculates accurate correction values. Features with projection differences can be translated perpendicular to the flight path, correcting their outlines and feature points. Specifically, based on DSM and DOM data acquisition technologies, the overhang principle and flight path data are used to determine the overhang correction value. A projection correction algorithm is designed, and the projection correction function is implemented through software development. The algorithm has been validated in geographic entity data acquisition and topographic map data production, improving data acquisition accuracy.
[0045] like Figure 1As shown, the specific implementation process of the data acquisition method based on DSM and DOM of the present invention includes:
[0046] S1. Data preprocessing: performing coordinate transformation and organization on the loaded data;
[0047] Simultaneously load DSM data, DOM data, flight route data, and range line data, and convert them into specific formats and structures based on their corresponding data characteristics.
[0048] The DOM data is a pushbroom orthophoto image, which shares the same coordinate system as the DSM data. Both are then used to generate model data in OSGB format.
[0049] Flight path data and extent line data are Shapefile data, and both are line data. Flight path data includes flight altitude information and flight path number. Extent line data is used to define the extent during image creation, determining the flight path to which the collected data belongs; its attributes include the corresponding flight path number. Figure 2 Loaded route data Figure 3 Taking the loaded range line data as an example, after conversion and processing, the following is obtained: Figure 4 The diagram showing the relationship between image location and flight path is as follows: Figure 4 As shown, the range of the ground feature vector data collected in the lower half of the loaded image is highlighted in blue, and the flight path number in its attributes corresponds to the flight path contained in the red box. Based on this, the flight path number and flight altitude information data corresponding to the collected vector data can be obtained.
[0050] S2, Data Acquisition
[0051] OSGB (Open Scene Gragh Binary) data is a commonly used oblique photogrammetric 3D model for generating data in the surveying and mapping field. The OSGB format uses compression algorithms and data structure optimizations, which can efficiently store and load large 3D models. It reduces file size and improves loading speed and performance.
[0052] Because the DSM data produced by ADS100 is automatically processed and not manually edited, some features in the OSGB format model have unclear edges, making it difficult to accurately acquire their planar positions. Therefore, it is necessary to acquire the contour information or feature point information of features based on DOM data. This DSM data has very high elevation accuracy; therefore, the elevation information of features is obtained based on the OSGB format model data generated from the DSM data. Given the different data structures and acquisition methods of DSM and DOM, a split-screen acquisition method is used to acquire the planar contour information and elevation information of features separately. The acquired vector data is displayed synchronously on both screens, and the display results are as follows: Figure 5 As shown.
[0053] Because the coordinate systems of the 2D and 3D data are the same, the mouse cursor in the display window is also synchronized. After acquiring vector data of feature outlines in the DOM imagery, the feature elevation acquisition function is used to acquire the elevation information of features in the OSGB model of the DSM data. To use the feature elevation acquisition function, first, click on the feature to obtain the entity code of the feature whose elevation information needs to be acquired, then click on the model to obtain the elevation data. The elevation data includes ground elevation information and the top outline information of the feature (for buildings, the building elevation). Figure 6 The displayed vector data shows that the thick blue box on the left side of the image represents the vector data collected from the DOM imagery, while the thin blue box on the right side represents the elevation information collected from the 3D data.
[0054] The elevation point data is associated with the features by using the feature relationship field in the vector data feature attribute information. The ground elevation data is entered into the ground elevation field of the feature, and the top outline information of the feature (building elevation for buildings) is entered into the eaves elevation field. Figure 7 It demonstrates the information associations between vector data, the relationships between ground features and elevation points, and collapsed roofs, which are identified through attribute fields.
[0055] S3. Projection correction through correction algorithm: The correction algorithm obtains the accurate correction amount, and the ground features with projection difference are translated perpendicular to the flight strip direction. The outline and feature points can be corrected back to obtain the true position of the ground feature outline.
[0056] Due to projection differences, DOM data contains inverted features. Therefore, this invention designs a special correction algorithm during the data acquisition process to perform projection correction, thereby solving the problem of spatial position correction of features and enabling the planar coordinates to be corrected to the correct position.
[0057] Pushbroom scanning uses a wide-angle optical system to image across the entire field of view. It arranges detectors in an array along the scanning direction (perpendicular to the flight direction) to sense the ground response and records the data using "scan" lines perpendicular to the flight direction, forming a two-dimensional image. The resulting image data is pushbroom data, and the ADS100 sensor is commonly used in the surveying industry for data acquisition.
[0058] Through in-depth analysis and research, it has been found that image overhang in ADS100 pushbroom data is related to the flight path direction. With the flight path centerline as the axis, buildings overhang to both sides, and the greater the distance between the ground feature and the flight path centerline, the greater the overhang error; the higher the ground feature, the greater the overhang error. The study revealed several distinct characteristics of image overhang: the overhang direction is perpendicular to the flight path direction; the overhang offset is directly proportional to the distance of the ground feature from the flight path centerline and the height of the ground feature, such as... Figure 8 The diagram shows the pattern of the image falling over, with the houses in the diagram being those on the side of the flight path.
[0059] The specific design of the correction algorithm includes: establishing a mathematical model of a certain point of the ground feature to obtain, for example... Figure 9 The simplified theoretical diagram shown has the following projection relationship: Figure 10 As shown; among them, the ground feature collection points O The coordinates are ( X 0, Y 0, Z 0), actual coordinates of ground features M ( X , Y , Z First node on the route A and end node B The coordinates are ( X 1, Y 1, Z 1) and ( X 2, Y 2, Z 2) Setting points O In a straight line AB The foot of the perpendicular is a point. N The coordinates are ( X n , Y n , Z n ),point N The coordinate calculation process is as follows:
[0060] First, calculate the vector:
[0061]
[0062] From the perpendicular relationship of vectors, we can obtain:
[0063]
[0064] point N In a straight line AB Based on the collinearity of vectors, we can conclude that:
[0065]
[0066] Good points O In a straight line AB The foot coordinates of the perpendicular ( X n , Y n , Z n )for:
[0067]
[0068] Wherein, the correction parameter K is:
[0069]
[0070] Due to the corrected points M ( X , Y , Z ) on the straight line ON Above, therefore OM and MN Collinearity:
[0071]
[0072] After correction M The plane coordinates are:
[0073] .
[0074] After loading flight path data and boundary line data, the correction algorithm can determine the location of vector features based on the flight strip number in the boundary line data attribute field, obtain their corresponding flight altitude, and perform projection correction. For example... Figure 11 As shown, the dashed line outlines the initial terrain features. After correction by the projection correction algorithm, the true location of the terrain features outlined by the solid line is obtained.
[0075] Finally, the obtained data can be quality checked to ensure its reliability.
[0076] Therefore, the data acquisition method based on DSM and DOM disclosed in this invention breaks the constraints of traditional acquisition methods. It can not only realize basic scale topographic map surveying and mapping functions, and new basic surveying and mapping geographic entity acquisition and editing functions, but also modeling data acquisition and editing functions. Testing has shown that both planar and elevation accuracy can meet the accuracy requirements for 1:2000 topographic map data acquisition, geographic entity and other vector data acquisition. It can be used for the acquisition of important geographic entity data in new basic surveying and mapping, and for updating 1:2000 and 1:10000 topographic maps. It can also be used for LOD2 model production and rapid LOD3 model production trials in general areas, as well as for refining individual building data in geographic national condition monitoring.
[0077] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention are also within the protection scope of the present invention.
Claims
1. A data acquisition method based on DSM and DOM, characterized in that: The following data collection steps are included: S1. Data Preprocessing: Simultaneously load DSM data, DOM data, flight route data, and range line data, and perform coordinate transformation and organization on the loaded data; S2. Vector Data Acquisition: Based on DOM data, vector data of ground feature outlines are acquired. Based on the OSGB format model generated from DSM data, elevation information of ground features is acquired. S3. Projection correction through correction algorithm: The correction algorithm obtains the accurate correction amount, and the ground features with projection difference are translated perpendicular to the flight strip direction. The outline and feature points can be corrected back to obtain the true position of the ground feature outline. In step S3, the correction algorithm design specifically includes: establishing a mathematical model of a certain point of the ground feature; wherein, the ground feature collection point... O The coordinates are ( X 0, Y 0, Z 0), actual coordinates of ground features M ( X , Y , Z First node on the route A and end node B The coordinates are ( X 1, Y 1, Z 1) and ( X 2, Y 2, Z 2) Setting points O In a straight line AB The foot of the perpendicular is a point. N The coordinates are ( X n , Y n , Z n ),point N The coordinate calculation process is as follows: First, calculate the vector: From the perpendicular relationship of vectors, we can obtain: point N In a straight line AB Based on the collinearity of vectors, we can conclude that: Good points O In a straight line AB The foot coordinates of the perpendicular ( X n , Y n , Z n )for: Wherein, the correction parameter K is: Due to the corrected points M ( X , Y , Z ) on the straight line ON Above, therefore OM and MN Collinearity: After correction M The plane coordinates are: After loading the flight path data and the boundary line data, the correction algorithm determines the location of the vector feature based on the flight strip number in the boundary line data attribute field, obtains its corresponding flight altitude, and performs projection correction.
2. The data acquisition method based on DSM and DOM according to claim 1, characterized in that: In step S1, the DSM data and the DOM data have the same coordinate system, and both are used to generate model data in OSGB format. The flight path data includes flight path elevation information and flight path number. The range line data is used as the range defined during image production to obtain the flight path number and flight path elevation information data corresponding to the collected vector data.
3. The data acquisition method based on DSM and DOM according to claim 2, characterized in that: Data is collected based on the ADS100 sensor.
4. The data acquisition method based on DSM and DOM according to claim 3, characterized in that: In step S2, after collecting vector data of ground feature outlines in the DOM data image, the ground feature entity codes for which elevation information needs to be collected are obtained, and then the elevation data is obtained by clicking on the OSGB data model of the DSM data.
5. The data acquisition method based on DSM and DOM according to claim 4, characterized in that: The collected elevation data includes ground elevation information and top outline information of ground features. The top outline information of buildings is the building elevation. The relationship between ground feature attributes and ground elevation points, building elevation points, and collapsed roofs is identified through attribute fields.
6. The data acquisition method based on DSM and DOM according to claim 5, characterized in that: The elevation point data is associated with the ground features by using the ground feature relationship field in the vector data ground feature attribute information. The ground elevation data is entered into the ground elevation field of the ground features, and the top outline information of the ground features, such as the building elevation for houses, is entered into the eaves elevation field.