Building surveying and mapping method based on aerial photography

Abstract

The invention relates to the technical field of building surveying and mapping, and discloses a building surveying and mapping method based on aerial photography, and the method comprises the steps: generating an initial building contour according to a building image data set; determining an initial shooting interval of the camera according to the basic size data; acquiring aerial image data of a to-be-surveyed building; performing three-dimensional reconstruction on the initial building contour according to the aerial image data, and generating an initial three-dimensional point cloud model of the building to be mapped; judging whether the initial shooting interval is adjusted or not according to the local density; when it is judged that the initial shooting interval is adjusted, collecting coverage condition data of the to-be-surveyed building, and calculating a shooting influence factor according to the coverage condition data and the local density; comparing the shooting influence factor with historical data, and adjusting the initial shooting interval according to a comparison result; and storing the shooting influence factor. The building surveying and mapping efficiency is improved, the surveying and mapping result quality is improved, and powerful technical support is provided for urban planning and construction.

Description

Technical Field

[0001] The present invention relates to the technical field of building surveying and mapping, and in particular to a building surveying and mapping method based on aerial photography. Background Art

[0002] Architectural surveying and mapping is to analyze and organize the actual measured objects and their data through on-site investigation and measurement of actual buildings, and then express them in plan, elevation and section using the formation principle of architectural plan, elevation and section drawings. Through on-site investigation and mapping of actual building objects, we can verify, consolidate and improve the theoretical knowledge learned, deepen the understanding of architectural plan, elevation, section, space and structure, and initially understand the relationship between the internal space of the building and the environmental space.

[0003] Building surveying plays a vital role in the process of urban planning and construction. It is the cornerstone to ensure the rational layout of cities, the safety of buildings and the perfect functions. However, traditional building surveying methods often rely on a lot of human resources and time investment, which not only increases the cost of the project, but also may lead to inefficiency. Especially in areas with complex terrain or densely built areas, traditional surveying methods often seem to be unable to cope with various challenges. The surveying work in these areas is not only time-consuming, but also prone to errors, affecting the final planning and construction quality.

[0004] Therefore, it is necessary to design an architectural surveying and mapping method based on aerial photography to solve the problems existing in current technology. Summary of the invention

[0005] In view of this, the present invention proposes a building surveying and mapping method based on aerial photography, aiming to solve the problems of low efficiency and poor accuracy of the building surveying and mapping method in the current technology.

[0006] The present invention proposes a building surveying and mapping method based on aerial photography, comprising the following steps:

[0007] S100: Determine a building to be surveyed, divide a surface of the building to be surveyed into a plurality of surveying areas, collect image data of each of the surveying areas and establish a building image data set, and generate an initial building outline according to the building image data set; obtain basic size data of the building to be surveyed, and determine an initial shooting interval of a camera according to the basic size data;

[0008] S200: Using a flying platform to carry the camera to shoot the building to be surveyed according to a preset flight path and at the initial shooting interval to obtain aerial image data of the building to be surveyed; performing three-dimensional reconstruction of the initial building outline according to the aerial image data to generate an initial three-dimensional point cloud model of the building to be surveyed;

[0009] S300: dividing the initial three-dimensional point cloud model into a plurality of monitoring areas, collecting the local density of each monitoring area, and determining whether to adjust the initial shooting interval according to the local density;

[0010] S400: when it is determined that the initial shooting interval is to be adjusted, collecting coverage data of the building to be surveyed, calculating a shooting influence factor according to the coverage data and local density; comparing the shooting influence factor with historical data, and adjusting the initial shooting interval according to the comparison result;

[0011] S500: storing the shooting influencing factors.

[0012] Furthermore, when generating an initial building outline according to the building image data set, it includes:

[0013] Extracting edge information of the building to be measured from the image data set, and identifying shape information of the building to be measured by an image processing algorithm;

[0014] Determine the basic building outline of the building to be measured by using geometric shape fitting technology based on the appearance information;

[0015] Extracting structural feature data of the building to be surveyed, optimizing the basic building outline according to the structural feature data, and obtaining an optimized building outline;

[0016] The optimized building outline is adjusted according to the basic dimension data to obtain the initial building outline.

[0017] Furthermore, obtaining basic size data of the building to be surveyed and mapping, and determining the initial shooting interval of the camera according to the basic size data, includes:

[0018] The basic size data includes the length, width and height of the building to be surveyed;

[0019] The initial shooting interval is calculated according to the length, width and height; the initial shooting interval is obtained by the following formula:

[0020]

[0021] Wherein, I represents the initial shooting interval; L represents the length; W represents the width; h represents the flight height of the flight platform; and C represents the constant coefficient.

[0022] Furthermore, when the initial building outline is three-dimensionally reconstructed according to the aerial image data to generate an initial three-dimensional point cloud model of the building to be surveyed, the method includes:

[0023] Extracting all viewing angle feature data from the aerial image data, and aligning all the viewing angle feature data by using image registration technology;

[0024] Using a stereo matching algorithm to extract three-dimensional point data corresponding to all the viewing angle feature data;

[0025] The three-dimensional point data is converted into the initial three-dimensional point cloud model through a point cloud generation algorithm.

[0026] Furthermore, collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density includes:

[0027] The local density is obtained by the following formula:

[0028]

[0029] Wherein, Di represents the local density of the i-th monitoring area; Ni represents the number of three-dimensional point data extracted in the i-th monitoring area; Ai represents the area of ​​the i-th monitoring area.

[0030] Furthermore, when collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density, the method further includes:

[0031] Classifying the monitoring areas to obtain important monitoring areas and non-important monitoring areas;

[0032] Comparing the local densities of all the important monitoring areas with the first local density threshold one by one, and counting the number of the important monitoring areas whose local density is less than the first local density threshold, which is recorded as the first monitoring number;

[0033] Comparing the local densities of all the non-important monitoring areas with the second local density threshold one by one, and counting the number of the non-important monitoring areas whose local density is less than the second local density threshold, which is recorded as the second monitoring number;

[0034] Performing weighted average calculation on the first monitored quantity and the second monitored quantity to obtain a comprehensive quantity value;

[0035] Determine whether to adjust the initial shooting interval according to the comprehensive quantity value.

[0036] Further, judging whether to adjust the initial shooting interval according to the comprehensive quantity value includes:

[0037] Comparing the comprehensive quantity value with the comprehensive quantity value threshold, and determining whether to adjust the initial shooting interval according to the comparison result;

[0038] When the comprehensive quantity value is greater than or equal to the comprehensive quantity value threshold, determining to adjust the initial shooting interval;

[0039] When the integrated quantity value is less than the integrated quantity value threshold, it is determined that the initial photographing interval is not adjusted.

[0040] Further, when it is determined that the initial shooting interval is to be adjusted, the coverage data of the building to be surveyed is collected, and the shooting influence factor is calculated according to the coverage data and the local density, including:

[0041] The coverage data include image overlap rate and surface coverage rate of the building to be mapped;

[0042] The shooting influence factor is calculated according to the image overlap rate and the surface coverage rate of the building to be mapped; the shooting influence factor is obtained by the following formula:

[0043]

[0044] Among them, If represents the shooting influence factor, R0 represents the image overlap rate; Rc represents the surface coverage rate of the building to be surveyed; α represents the weight coefficient.

[0045] Furthermore, comparing the shooting influencing factor with historical data and adjusting the initial shooting interval according to the comparison result includes:

[0046] When there is a historical shooting factor that is the same as the shooting influencing factor in the historical data, adjusting the initial shooting interval according to a historical adjustment coefficient corresponding to the historical shooting factor, and obtaining a final shooting interval;

[0047] When there is no historical shooting factor identical to the shooting influencing factor in the historical data, all historical shooting factors in the historical data that are greater than the shooting influencing factor are obtained, and a historical shooting factor data set is established, and the initial shooting interval is adjusted according to the historical shooting factor data set.

[0048] Further, when the initial shooting interval is adjusted according to the historical shooting factor data set, it includes:

[0049] Calculating an average value of the historical shooting factors according to the historical shooting factor data set, and recording it as the shooting average value;

[0050] Comparing the shooting average value with a first shooting average value threshold and a second shooting average value threshold, determining an adjustment coefficient of the initial shooting interval according to the comparison result, and adjusting the initial shooting interval according to the adjustment coefficient; wherein the first shooting average value threshold is less than the second shooting average value threshold;

[0051] When the shooting average value is less than or equal to the first shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the first adjustment coefficient, and taking the product value of the first adjustment coefficient and the initial shooting interval as the final shooting interval;

[0052] When the shooting average value is greater than the first shooting average value threshold and less than or equal to the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the second adjustment coefficient, and taking the product value of the second adjustment coefficient and the initial shooting interval as the final shooting interval;

[0053] When the shooting average value is greater than the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as a third adjustment coefficient, and taking the product value of the third adjustment coefficient and the initial shooting interval as the final shooting interval;

[0054] The first adjustment coefficient is smaller than the second adjustment coefficient, and the second adjustment coefficient is smaller than the third adjustment coefficient.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows: the building surveying and mapping method based on aerial photography provided by the present invention can effectively improve the efficiency and accuracy of building surveying and mapping. Through aerial photography technology, detailed image data of buildings and their surroundings can be obtained in a shorter time, thereby reducing manpower and time costs. The building surveying and mapping method based on aerial photography provided by the present invention can adapt to the surveying and mapping needs of complex terrain and densely built areas, and the initial three-dimensional point cloud model generated by three-dimensional reconstruction technology provides accurate data support for subsequent building planning and design. At the same time, through the local density analysis of the monitoring area and the calculation of the shooting influencing factors, the shooting interval can be dynamically adjusted to further optimize the surveying and mapping process and ensure the integrity and accuracy of the data. Finally, the building surveying and mapping method based on aerial photography provided by the present invention not only improves the efficiency of building surveying and mapping, but also improves the quality of surveying and mapping results, providing strong technical support for urban planning and construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0057] Figure 1 A flowchart of a building surveying and mapping method based on aerial photography provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] See also Figure 1 As shown, in some embodiments of the present application, this embodiment provides a building surveying and mapping method based on aerial photography, comprising the following steps:

[0060] S100: Determine a building to be surveyed, divide the surface of the building to be surveyed into several surveying areas, collect image data of each surveying area and establish a building image data set, generate an initial building outline according to the building image data set; obtain basic size data of the building to be surveyed, and determine an initial shooting interval of the camera according to the basic size data;

[0061] S200: Using a camera mounted on a flying platform to shoot the building to be surveyed according to a preset flight path and at an initial shooting interval to obtain aerial image data of the building to be surveyed; performing three-dimensional reconstruction of the initial building outline according to the aerial image data to generate an initial three-dimensional point cloud model of the building to be surveyed;

[0062] S300: dividing the initial three-dimensional point cloud model into a plurality of monitoring areas, collecting the local density of each monitoring area, and determining whether to adjust the initial shooting interval according to the local density;

[0063] S400: when it is determined that the initial shooting interval is to be adjusted, the coverage data of the building to be surveyed is collected, and a shooting influence factor is calculated according to the coverage data and the local density; the shooting influence factor is compared with the historical data, and the initial shooting interval is adjusted according to the comparison result;

[0064] S500: storing shooting influencing factors.

[0065] In this embodiment, the image data of the surveying area is collected by a camera without a flying platform.

[0066] It is understandable that in step S100, the acquisition of basic dimensional data can be achieved in a variety of ways, such as using a laser rangefinder, an ultrasonic rangefinder, or through existing architectural drawing information; when determining the initial shooting interval of the camera, the selection of the constant coefficient C depends on the resolution of the camera, the flight speed of the flight platform, and the desired mapping accuracy; the flight platform is a drone, helicopter, or other type of aircraft, and the camera it carries needs to have high resolution and stable performance to ensure the acquisition of high-quality aerial image data; the division of the monitoring area can be based on the structural characteristics and complexity of the building to ensure the accuracy and efficiency of the three-dimensional reconstruction; the storage of shooting influencing factors uses a database management system to facilitate subsequent data retrieval and analysis.

[0067] It can be understood that the building surveying and mapping method based on aerial photography provided in this embodiment can effectively improve the efficiency and accuracy of building surveying and mapping. Through aerial photography technology, detailed image data of buildings and their surroundings can be obtained in a shorter time, thereby reducing manpower and time costs. The building surveying and mapping method based on aerial photography provided in this embodiment can adapt to the surveying and mapping needs of complex terrain and densely built areas. The initial three-dimensional point cloud model generated by three-dimensional reconstruction technology provides accurate data support for subsequent building planning and design. At the same time, through the local density analysis of the monitoring area and the calculation of the shooting influencing factors, the shooting interval can be dynamically adjusted to further optimize the surveying and mapping process and ensure the integrity and accuracy of the data. Finally, the building surveying and mapping method based on aerial photography provided in this embodiment not only improves the efficiency of building surveying and mapping, but also improves the quality of surveying and mapping results, providing strong technical support for urban planning and construction.

[0068] Specifically, when generating an initial building outline based on a building image dataset, it includes:

[0069] Extract edge information of the building to be mapped from the image data set, and identify the shape information of the building to be mapped through image processing algorithms;

[0070] Based on the appearance information, the geometric shape fitting technology is used to determine the basic building outline of the building to be surveyed;

[0071] Extracting structural feature data of the building to be surveyed, optimizing the basic building outline according to the structural feature data, and obtaining an optimized building outline;

[0072] The optimized building outline is adjusted according to the basic dimension data to obtain the initial building outline.

[0073] It is understandable that the shape information of the building to be surveyed refers to features such as the building's outline, door and window locations, and roof shape. When extracting edge information, an edge detection algorithm such as the Canny edge detector can be used to identify significant edges in the image. Geometric shape fitting techniques can include fitting of basic geometric shapes such as straight lines, curves, and polygons to form a preliminary model of the building's outline. The extraction of structural feature data may involve identifying and classifying specific parts of the building, such as windows, doors, balconies, etc., to further refine the building's outline. The adjustment of basic size data ensures that the size of the building's outline matches the actual building, providing an accurate reference for subsequent three-dimensional reconstruction. Through these steps, an accurate initial building outline can be generated, laying a solid foundation for three-dimensional reconstruction of building surveying.

[0074] Specifically, obtaining the basic size data of the building to be surveyed and mapping and determining the initial shooting interval of the camera according to the basic size data include:

[0075] Basic dimension data include the length, width and height of the building to be surveyed;

[0076] The initial shooting interval is calculated based on the length, width and height; the initial shooting interval is obtained by the following formula:

[0077]

[0078] Wherein, I represents the initial shooting interval; L represents the length; W represents the width; h represents the flight height of the flight platform; and C represents the constant coefficient.

[0079] It is understandable that the selection of C is related to the resolution of the camera, the flight speed of the flight platform, and the desired mapping accuracy. For example, if the desired mapping accuracy is high, the constant coefficient C may take a smaller value to ensure that the image captured by the camera can capture enough details. On the contrary, if the mapping accuracy requirement is not particularly high, or in order to improve shooting efficiency, the value of C can be appropriately increased, thereby reducing the number of shots. In addition, the flight altitude h of the flight platform will also affect the calculation of the initial shooting interval I. The higher the flight altitude, the initial shooting interval may need to be increased accordingly in order to maintain the same mapping accuracy. Through such calculations and adjustments, it can be ensured that high-quality aerial image data can be obtained under different flight altitudes and mapping accuracy requirements, providing a reliable foundation for subsequent three-dimensional reconstruction.

[0080] Specifically, when the initial building outline is 3D reconstructed based on the aerial image data to generate the initial 3D point cloud model of the building to be surveyed, it includes:

[0081] Extract all view feature data from the aerial image data and align all view feature data using image registration technology;

[0082] A stereo matching algorithm is used to extract the three-dimensional point data corresponding to all the viewing angle feature data;

[0083] The 3D point data is converted into an initial 3D point cloud model through a point cloud generation algorithm.

[0084] It is understandable that image registration technology is a key step to ensure that images taken from different perspectives can be accurately aligned, which usually involves complex image processing algorithms such as feature point matching, image transformation, and error correction. The stereo matching algorithm is used to extract depth information from the registered multi-view images and generate point data in three-dimensional space. The point cloud generation algorithm integrates these point data to form a continuous three-dimensional point cloud model, providing basic data for subsequent three-dimensional modeling and analysis. In the three-dimensional reconstruction process, the occlusion problem of buildings must also be considered to ensure that all necessary details are captured and reconstructed. Through the comprehensive application of these technologies, a detailed and accurate three-dimensional point cloud model can be generated, providing strong data support for architectural surveying and subsequent urban planning.

[0085] Specifically, collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density include:

[0086] The local density is obtained by:

[0087]

[0088] Wherein, Di represents the local density of the i-th monitoring area; Ni represents the number of three-dimensional point data extracted in the i-th monitoring area; Ai represents the area of ​​the i-th monitoring area.

[0089] Specifically, when collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density, it also includes:

[0090] Classify the monitoring areas to obtain important monitoring areas and non-important monitoring areas;

[0091] The local densities of all important monitoring areas are compared with the first local density threshold one by one, and the number of important monitoring areas whose local density is less than the first local density threshold is counted, which is recorded as the first monitoring number;

[0092] The local densities of all non-important monitoring areas are compared with the second local density threshold one by one, and the number of non-important monitoring areas whose local density is less than the second local density threshold is counted, which is recorded as the second monitoring number;

[0093] Perform weighted average calculation on the first monitoring quantity and the second monitoring quantity to obtain a comprehensive quantity value;

[0094] Whether to adjust the initial shooting interval is determined based on the comprehensive quantity value.

[0095] Specifically, judging whether to adjust the initial shooting interval according to the comprehensive quantity value includes:

[0096] Compare the comprehensive quantity value with the comprehensive quantity value threshold, and determine whether to adjust the initial shooting interval according to the comparison result;

[0097] When the comprehensive quantity value is greater than or equal to the comprehensive quantity value threshold, it is determined that the initial shooting interval is adjusted;

[0098] When the integrated quantity value is less than the integrated quantity value threshold, it is determined that the initial photographing interval is not adjusted.

[0099] It is understandable that when the comprehensive quantity value exceeds the preset adjustment threshold, the initial shooting interval needs to be adjusted. The purpose of the adjustment is to ensure the quality of 3D reconstruction of all monitoring areas, especially for those areas with low local density, the number of shots needs to be increased to improve the integrity of the data. During the adjustment process, the shooting interval can be appropriately reduced to obtain more detailed information.

[0100] Specifically, when it is determined that the initial shooting interval is adjusted, the coverage data of the building to be surveyed is collected, and the shooting influence factor is calculated based on the coverage data and the local density, including:

[0101] Coverage data include image overlap rate and surface coverage rate of buildings to be mapped;

[0102] The shooting influence factor is calculated based on the image overlap rate and the surface coverage rate of the building to be mapped. The shooting influence factor is obtained by the following formula:

[0103]

[0104] Among them, If represents the shooting influence factor, R0 represents the image overlap rate; Rc represents the surface coverage rate of the building to be surveyed; α represents the weight coefficient.

[0105] It is understandable that in aerial photogrammetry, the image overlap rate refers to the ratio of the overlapping area between two adjacent aerial images to the area of ​​a single image. The surface coverage of the building to be mapped refers to the ratio of the photographed building surface to the actual building surface area, which is directly related to the integrity and accuracy of the three-dimensional model. The weight coefficient α is used to balance the contribution of the image overlap rate and the building surface coverage rate to the shooting influencing factors. The value of α depends on the specific application scenario and accuracy requirements. By setting the α value reasonably, the shooting strategy can be optimized to ensure that the number of shots is minimized and work efficiency is improved while ensuring the quality of three-dimensional reconstruction.

[0106] Specifically, the shooting influencing factors are compared with historical data, and the initial shooting interval is adjusted according to the comparison results, including:

[0107] When there is a historical shooting factor that is the same as the shooting influence factor in the historical data, the initial shooting interval is adjusted according to the historical adjustment coefficient corresponding to the historical shooting factor, and the final shooting interval is obtained;

[0108] When there is no historical shooting factor identical to the shooting influence factor in the historical data, all historical shooting factors in the historical data that are greater than the shooting influence factor are obtained, and a historical shooting factor data set is established, and the initial shooting interval is adjusted according to the historical shooting factor data set.

[0109] In this embodiment, historical data refers to the shooting influence factors and corresponding adjustment coefficients collected in previous surveying and mapping tasks. These data are recorded and stored for analysis and comparison to guide current and future shooting interval adjustments. By comparing the current shooting influence factors with similar factors in historical data, it can be determined whether the initial shooting interval needs to be adjusted and how to adjust it.

[0110] Specifically, when adjusting the initial shooting interval according to the historical shooting factor dataset, it includes:

[0111] Calculate the average value of the historical shooting factors according to the historical shooting factor data set, and record it as the shooting average value;

[0112] Comparing the shooting average value with the first shooting average value threshold and the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval according to the comparison result, and adjusting the initial shooting interval according to the adjustment coefficient; wherein the first shooting average value threshold is less than the second shooting average value threshold;

[0113] When the shooting average value is less than or equal to the first shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the first adjustment coefficient, and taking the product value of the first adjustment coefficient and the initial shooting interval as the final shooting interval;

[0114] When the shooting average value is greater than the first shooting average value threshold value and less than or equal to the second shooting average value threshold value, determining the adjustment coefficient of the initial shooting interval as the second adjustment coefficient, and taking the product value of the second adjustment coefficient and the initial shooting interval as the final shooting interval;

[0115] When the shooting average value is greater than the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the third adjustment coefficient, and taking the product value of the third adjustment coefficient and the initial shooting interval as the final shooting interval;

[0116] The first adjustment coefficient is smaller than the second adjustment coefficient, and the second adjustment coefficient is smaller than the third adjustment coefficient.

[0117] It is understandable that by setting different adjustment coefficients, different shooting conditions and environmental changes can be flexibly responded to. The building surveying and mapping method based on aerial photography provided in this embodiment not only improves the efficiency of building surveying and mapping, but also improves the quality of surveying and mapping results, providing strong technical support for urban planning and construction.

[0118] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0119] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A building surveying and mapping method based on aerial photography, characterized in that: include: Determine a building to be surveyed, divide a plurality of surveying areas on the surface of the building to be surveyed, collect image data of each of the surveying areas and establish a building image data set, and generate an initial building outline according to the building image data set; obtain basic size data of the building to be surveyed, and determine an initial shooting interval of a camera according to the basic size data; The camera is mounted on a flying platform to shoot the building to be surveyed according to a preset flight path and at the initial shooting interval to obtain aerial image data of the building to be surveyed; the initial building outline is three-dimensionally reconstructed according to the aerial image data to generate an initial three-dimensional point cloud model of the building to be surveyed; Dividing the initial three-dimensional point cloud model into a plurality of monitoring areas, collecting the local density of each monitoring area, and determining whether to adjust the initial shooting interval according to the local density; When it is determined that the initial shooting interval is to be adjusted, the coverage data of the building to be surveyed is collected, and a shooting influence factor is calculated according to the coverage data and the local density; the shooting influence factor is compared with the historical data, and the initial shooting interval is adjusted according to the comparison result; The shooting influencing factor is stored.

2. The building surveying and mapping method based on aerial photography according to claim 1, characterized in that: When generating an initial building outline according to the building image dataset, the method includes: Extracting edge information of the building to be measured from the image data set, and identifying shape information of the building to be measured by an image processing algorithm; Determine the basic building outline of the building to be measured by using geometric shape fitting technology based on the appearance information; Extracting structural feature data of the building to be surveyed, optimizing the basic building outline according to the structural feature data, and obtaining an optimized building outline; The optimized building outline is adjusted according to the basic dimension data to obtain the initial building outline.

3. The building surveying and mapping method based on aerial photography according to claim 1, characterized in that: The basic size data of the building to be surveyed is obtained, and the initial shooting interval of the camera is determined according to the basic size data, including: The basic size data includes the length, width and height of the building to be surveyed; The initial shooting interval is calculated according to the length, width and height; the initial shooting interval is obtained by the following formula: Wherein, I represents the initial shooting interval; L represents the length; W represents the width; h represents the flight height of the flight platform; and C represents the constant coefficient.

4. The building surveying and mapping method based on aerial photography according to claim 1, characterized in that: When the initial building outline is three-dimensionally reconstructed according to the aerial image data to generate an initial three-dimensional point cloud model of the building to be surveyed, the method includes: Extracting all viewing angle feature data from the aerial image data, and aligning all the viewing angle feature data by using image registration technology; Using a stereo matching algorithm to extract three-dimensional point data corresponding to all the viewing angle feature data; The three-dimensional point data is converted into the initial three-dimensional point cloud model through a point cloud generation algorithm.

5. The building surveying and mapping method based on aerial photography according to claim 1, characterized in that: Collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density includes: The local density is obtained by the following formula: Wherein, Di represents the local density of the i-th monitoring area; Ni represents the number of three-dimensional point data extracted in the i-th monitoring area; Ai represents the area of ​​the i-th monitoring area.

6. The building surveying and mapping method based on aerial photography according to claim 5, characterized in that: When collecting the local density of each monitoring area and determining whether to adjust the initial shooting interval according to the local density, the method further includes: Classifying the monitoring areas to obtain important monitoring areas and non-important monitoring areas; Comparing the local densities of all the important monitoring areas with the first local density threshold one by one, and counting the number of the important monitoring areas whose local density is less than the first local density threshold, which is recorded as the first monitoring number; Comparing the local densities of all the non-important monitoring areas with the second local density threshold one by one, and counting the number of the non-important monitoring areas whose local density is less than the second local density threshold, which is recorded as the second monitoring number; Performing weighted average calculation on the first monitored quantity and the second monitored quantity to obtain a comprehensive quantity value; Determine whether to adjust the initial shooting interval according to the comprehensive quantity value.

7. The building surveying and mapping method based on aerial photography according to claim 6, characterized in that: When judging whether to adjust the initial shooting interval according to the comprehensive quantity value, it includes: Comparing the comprehensive quantity value with the comprehensive quantity value threshold, and determining whether to adjust the initial shooting interval according to the comparison result; When the comprehensive quantity value is greater than or equal to the comprehensive quantity value threshold, determining to adjust the initial shooting interval; When the integrated quantity value is less than the integrated quantity value threshold, it is determined that the initial photographing interval is not adjusted.

8. The building surveying and mapping method based on aerial photography according to claim 1, characterized in that: When it is determined that the initial shooting interval is to be adjusted, collecting coverage data of the building to be surveyed and mapping, and calculating the shooting influence factor according to the coverage data and the local density, including: The coverage data include image overlap rate and surface coverage rate of the building to be mapped; The shooting influence factor is calculated according to the image overlap rate and the surface coverage rate of the building to be mapped; the shooting influence factor is obtained by the following formula: Among them, If represents the shooting influence factor, R0 represents the image overlap rate; Rc represents the surface coverage rate of the building to be surveyed; α represents the weight coefficient.

9. The building surveying and mapping method based on aerial photography according to claim 8, characterized in that: The shooting influencing factor is compared with historical data, and the initial shooting interval is adjusted according to the comparison result, including: When there is a historical shooting factor that is the same as the shooting influencing factor in the historical data, adjusting the initial shooting interval according to a historical adjustment coefficient corresponding to the historical shooting factor, and obtaining a final shooting interval; When there is no historical shooting factor identical to the shooting influencing factor in the historical data, all historical shooting factors in the historical data that are greater than the shooting influencing factor are obtained, and a historical shooting factor data set is established, and the initial shooting interval is adjusted according to the historical shooting factor data set.

10. The building surveying and mapping method based on aerial photography according to claim 9, characterized in that: When the initial shooting interval is adjusted according to the historical shooting factor data set, it includes: Calculating an average value of the historical shooting factors according to the historical shooting factor data set, and recording it as the shooting average value; Comparing the shooting average value with a first shooting average value threshold and a second shooting average value threshold, determining an adjustment coefficient of the initial shooting interval according to the comparison result, and adjusting the initial shooting interval according to the adjustment coefficient; wherein the first shooting average value threshold is less than the second shooting average value threshold; When the shooting average value is less than or equal to the first shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the first adjustment coefficient, and taking the product value of the first adjustment coefficient and the initial shooting interval as the final shooting interval; When the shooting average value is greater than the first shooting average value threshold and less than or equal to the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as the second adjustment coefficient, and taking the product value of the second adjustment coefficient and the initial shooting interval as the final shooting interval; When the shooting average value is greater than the second shooting average value threshold, determining the adjustment coefficient of the initial shooting interval as a third adjustment coefficient, and taking the product value of the third adjustment coefficient and the initial shooting interval as the final shooting interval; The first adjustment coefficient is smaller than the second adjustment coefficient, and the second adjustment coefficient is smaller than the third adjustment coefficient.

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