Modeling method and system for complex terrain

Abstract

The invention discloses a modeling method and system for a complex terrain, and relates to the technical field of modeling, and the method comprises the steps: determining an initial region, needing to be modeled, of the complex terrain; obtaining a minimum rectangle containing the initial region as a standard region, and mapping to obtain an initial plane graph; integrating the initial plane graph into a longitude and latitude coordinate system, and dividing the initial plane graph into a plurality of equal rectangular areas; constructing a three-dimensional model of each rectangular area; correcting the three-dimensional model of the adjacent rectangular areas by adopting a first method to obtain a corrected three-dimensional model; obtaining an aerial survey image, determining a plurality of feature points in each rectangular region, obtaining a first image corresponding to each rectangular region, and mapping the first image to the corresponding corrected three-dimensional model; smoothing the first image of the adjacent rectangular areas by adopting a second method to obtain a first processing result; and generating a standard three-dimensional model of the complex terrain based on the correction result and the first processing result. According to the method, the modeling accuracy is guaranteed on the premise of improving the modeling efficiency of the complex terrain.

Description

Technical Field

[0001] The present invention relates to the field of modeling technology, and in particular to a complex terrain modeling method and system. Background Art

[0002] Terrain is a relatively complex natural landscape. Three-dimensional terrain is simulated by modeling, perspective projection, and texture mapping. The generated terrain map can realistically reflect the external real world. Compared with traditional paper topographic maps and computer-generated line topographic maps, the three-dimensional topographic map after modeling is more realistic and closer to reality. In recent years, three-dimensional topographic maps have been increasingly widely used in land and resources surveys, urban simulations, virtual reality, and other fields. They are also of great significance for spatial analysis, planning decisions, etc.

[0003] Although the current modeling of conventional 3D terrain can be realistic and close to reality, and can also ensure modeling efficiency, for complex 3D terrain, because complex terrain means that a large amount of terrain data needs to be processed, modeling takes a lot of time, and the accuracy of modeling cannot be guaranteed. Therefore, a method for modeling complex 3D terrain is urgently needed to improve the accuracy and efficiency of modeling. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a complex terrain modeling method, the method comprising the following steps:

[0005] Acquire basic data of complex terrain, and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data;

[0006] Obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map;

[0007] Constructing a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrating the initial plane map into the coordinate system, and dividing the initial plane map into a plurality of equal rectangular areas;

[0008] Obtain GIS data and elevation data for each rectangular area and construct an initial three-dimensional model for each rectangular area;

[0009] Using the first method to correct the initial three-dimensional models of any two adjacent rectangular areas to obtain a correction result, and based on the correction result, obtaining a corrected three-dimensional model of each rectangular area;

[0010] Acquire the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, acquire a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model;

[0011] Using the second method to perform smoothing processing on the first image of any two adjacent rectangular areas to obtain a first processing result;

[0012] Based on the correction result and the first processing result, a standard three-dimensional model of the complex terrain is generated.

[0013] The present invention is implemented through the following technical scheme: first, by obtaining basic data of complex terrain (such as drawings or satellite images, etc.), based on the basic data, the initial area where the complex terrain needs to be modeled is determined, the minimum rectangle containing the initial area is obtained as the standard area, the standard area is mapped to the horizontal plane to obtain an initial plan view, and then a coordinate system with longitude and latitude as horizontal and vertical coordinates is constructed, the initial plan view is integrated into the coordinate system, and the initial plan view is divided into a number of equal rectangular areas. The above steps realize the conversion of complex terrain into an initial plan view containing multiple rectangular areas, and realize search and positioning through the coordinate system.

[0014] Obtain the GIS data and elevation data of each rectangular area, and construct an initial 3D model of each rectangular area. At this time, if the initial 3D models of all rectangular areas are fused, the initial 3D model of the complex terrain can be obtained. However, when adjacent rectangular areas are fused, due to reasons such as data accuracy, it is impossible to ensure a smooth transition between adjacent 3D models, resulting in abrupt phenomena between adjacent 3D models. Therefore, this solution adopts the first method to correct the 3D models of any adjacent rectangular areas to ensure that all rectangular areas can smoothly transition when fused, thereby reducing the abrupt phenomenon between the 3D models of different rectangular areas.

[0015] The aerial survey images of the standard area are obtained and processed to obtain the processing results, a preset number of first feature points are determined in each rectangular area, and the first image corresponding to each rectangular area is obtained based on the first feature points of each rectangular area and all the obtained aerial survey images. The first feature points of each rectangular area are used to locate the aerial survey image and then crop it to obtain the corresponding first image, and then each first image is mapped to the corresponding corrected three-dimensional model. However, when all the first images are fused, the connection between adjacent first images is prone to disharmony due to splicing and other reasons. Therefore, this solution adopts the second method to smooth the adjacent first images, so that the transition between adjacent first images is smoother and the disharmony at the connection between adjacent first images is reduced.

[0016] Finally, a standard three-dimensional model of the complex terrain is generated based on the corrected three-dimensional model and all the first images that have been smoothed.

[0017] As an optional technical solution, the first method includes:

[0018] Transition areas are preset around each rectangular area, and the transition area of ​​each rectangular area includes four overlapping areas and four non-overlapping areas;

[0019] Obtain an arbitrary rectangular area as a second rectangular area, and obtain a non-overlapping area in the second rectangular area as area E and an overlapping area as area F;

[0020] Obtain an adjacent non-overlapping area of ​​the area E and record it as area G, and count and calculate the average elevation value of the area E as the first elevation value, and the average elevation value of the area G as the second elevation value;

[0021] Calculate a first difference between the first elevation value and the second elevation value, and determine whether the first difference is less than a first threshold value. If not, do nothing. If yes, calculate an average value of the first elevation value and the second elevation value as a third elevation value. Based on the third elevation value, adjust the elevation values ​​of the area E and the area G, and complete the correction of the three-dimensional model corresponding to the area E and the area G.

[0022] Place the region F and all adjacent overlapping regions into a preset region set, and count and calculate the average elevation value of each region in the preset region set to obtain a calculation result;

[0023] Based on the calculation result, the difference between the average elevation values ​​corresponding to any two areas in the preset area set is calculated and recorded as the second difference, and it is determined whether all the second difference values ​​are less than the first threshold value. If so, the average of the average elevation values ​​of all areas in the preset area set is calculated and recorded as the fourth elevation value. Based on the fourth elevation value, the elevation values ​​of all areas in the preset area set are adjusted to complete the correction of the corresponding three-dimensional models of all areas in the preset area set. If not, no action is taken.

[0024] As an optional technical solution, the second method includes:

[0025] Obtaining first images corresponding to any two adjacent rectangular areas and recording them as second images and third images respectively;

[0026] Determine whether there is an overlapping area between the second image and the third image, if not, do not take any action, if yes, obtain the initial pixel value of each pixel in the overlapping area, assign a weight value to each pixel in the overlapping area using the first formula to obtain an assignment result, and based on the assignment result, use the second formula to calculate the initial pixel value of each pixel in the overlapping area to obtain a corresponding fused pixel value;

[0027] Based on the fused pixel value of each pixel point in the overlapping area, a smoothing process is performed on the overlapping area of ​​the second image and the third image.

[0028] As an optional technical solution, the first formula is:

[0029]

[0030] δ 1 is the weight value of a single pixel in the overlapping area in the second image, δ 2 is the weight value of a single pixel point in the overlapping area in the third image, d 1 is the distance between a single pixel point in the overlapping area and the center point of the second image, d 2 is the distance between a single pixel point in the overlapping area and the center point of the third image, and B is a constant.

[0031] As an optional technical solution, the second formula is:

[0032] W ′ =δ 1 ×W 1 +δ 2 ×W 2

[0033] W ′ is the fused pixel value of a single pixel in the overlapping area, W 1 is the initial pixel value of a single pixel point in the overlapping area in the second image, W 2 is the initial pixel value of a single pixel point in the overlapping area in the third image.

[0034] As an optional technical solution, the method further includes optimizing the standard three-dimensional model:

[0035] Obtaining the first image of each rectangular area and processing it to obtain a corresponding binary image;

[0036] Obtaining a first ratio between the area of ​​the shadow region in each binary image and the area of ​​the corresponding binary image to obtain a first acquisition result;

[0037] Based on the first acquisition result, different rectangular areas are graded, and the grade of the rectangular area is proportional to the corresponding first ratio;

[0038] Acquire all aerial survey images of the complex terrain within a preset time period to obtain a second acquisition result, and based on the second acquisition result, process all first images of each rectangular area and put them into a first data set;

[0039] Based on the level of each rectangular area, selecting a corresponding number of second feature points in each rectangular area, where the number of the second feature points is proportional to the level of the corresponding rectangular area;

[0040] Obtaining the pixel points contained in all the second feature points in each rectangular area, and based on the corresponding first data set, processing to obtain a change curve of the pixel points corresponding to each second feature point in each rectangular area, to obtain a second processing result;

[0041] Based on the second processing result, within the preset time period, the pixel points corresponding to each second feature point in each rectangular area are updated to complete the optimization of the standard three-dimensional model.

[0042] As an optional technical solution, the first ratio is calculated by the third formula:

[0043]

[0044] α n is the first ratio, A n is the shadow area in the binary image, S n is the area of ​​the binary image.

[0045] As an optional technical solution, based on the first acquisition result, classifying different rectangular areas into different levels includes:

[0046] Acquire historical data of all first ratios, divide the first ratios into data intervals based on the historical data, and assign a corresponding grade value to each data interval;

[0047] Obtain an arbitrary rectangular area as a first rectangular area, and obtain a first ratio of the first rectangular area as a second ratio;

[0048] The data interval corresponding to the second ratio is obtained as a first data interval;

[0049] The level corresponding to the first data interval is obtained as the level of the first rectangular area.

[0050] Obtain a first ratio of an arbitrary rectangular area and record it as a second ratio, and obtain a data interval corresponding to the second ratio and record it as a first data interval;

[0051] The level value corresponding to the first data interval is obtained as the level of the first rectangular area.

[0052] As an optional technical solution, obtaining and processing the aerial survey images of the standard area includes: based on the aerial survey video stream of the standard area, obtaining multiple frames of aerial survey images of the standard area and performing correction processing.

[0053] In order to solve the deficiencies of the prior art, the present invention further provides a complex terrain modeling system, the system comprising:

[0054] An initial area unit is used to obtain basic data of complex terrain and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data;

[0055] A mapping unit, used for obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map;

[0056] A coordinate system unit, used to construct a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrate the initial plane map into the coordinate system, and divide the initial plane map into a plurality of equal rectangular areas;

[0057] The initial three-dimensional model unit is used to obtain the GIS data and elevation data of each rectangular area and construct an initial three-dimensional model of each rectangular area;

[0058] A correction unit, configured to correct the initial three-dimensional models of any two adjacent rectangular areas by using a first method to obtain a correction result, and obtain a corrected three-dimensional model of each rectangular area based on the correction result;

[0059] A mapping unit is used to obtain the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, obtain a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model;

[0060] A smoothing processing unit, used for performing smoothing processing on the first image of any two adjacent rectangular areas by using a second method to obtain a first processing result;

[0061] A standard three-dimensional model unit is used to generate a standard three-dimensional model of the complex terrain based on the first processing result.

[0062] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0063] The present invention discloses a method for modeling complex terrain. By converting the modeling of complex terrain into processing of multiple rectangular areas, the difficulty of data processing is reduced, and the modeling of multiple rectangular areas can be carried out simultaneously, thereby improving the modeling efficiency. However, the separate modeling and mapping of multiple rectangular areas also need to consider the incoordination phenomenon during fusion. Therefore, the present invention also adopts the first method and the second method respectively, and performs processing on the fusion of three-dimensional models of multiple rectangular areas and the fusion of first images, thereby ensuring the accuracy of complex terrain modeling while improving the efficiency of complex terrain modeling.

[0064] The present invention also discloses a method for optimizing a standard three-dimensional model of complex terrain, by obtaining and processing a binary image of each rectangular area, dividing each rectangular area into levels, judging the coverage ratio of vegetation and the like in each rectangular area by the level, and then selecting a corresponding number of feature points based on the level of each rectangular area, the larger the vegetation coverage area and the higher the level of the rectangular area, the more corresponding feature points are selected, and then obtaining a change curve of the pixel points included in the feature points within a preset time period, and updating the feature points included in each rectangular area based on the corresponding change curve, thereby achieving the effect of updating the entire standard three-dimensional model of complex terrain within the preset time period, and further improving the authenticity of the three-dimensional modeling of complex terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of the present invention, and do not constitute a limitation on the embodiments of the present invention;

[0066] Figure 1 It is a schematic flow chart of a complex terrain modeling method in the present invention;

[0067] Figure 2 It is a schematic diagram of the transition area corresponding to the rectangular area in the present invention;

[0068] Figure 3 It is a schematic diagram of the composition of a complex terrain modeling system in the present invention. DETAILED DESCRIPTION

[0069] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0070] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those within the scope of this description. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0071] Embodiment 1

[0072] Please refer to Figure 1 , Figure 1 The figure is a flow chart of a complex terrain modeling method in the present invention, and the method comprises the following steps:

[0073] Acquire basic data of complex terrain, and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data;

[0074] Obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map;

[0075] Constructing a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrating the initial plane map into the coordinate system, and dividing the initial plane map into a plurality of equal rectangular areas;

[0076] Obtain GIS data and elevation data for each rectangular area and construct an initial three-dimensional model for each rectangular area;

[0077] Using the first method to correct the initial three-dimensional models of any two adjacent rectangular areas to obtain a correction result, and based on the correction result, obtaining a corrected three-dimensional model of each rectangular area;

[0078] Acquire the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, acquire a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model;

[0079] Using the second method to perform smoothing processing on the first image of any two adjacent rectangular areas to obtain a first processing result;

[0080] Based on the correction result and the first processing result, a standard three-dimensional model of the complex terrain is generated.

[0081] The specific embodiments of the present invention are as follows:

[0082] Modeling preprocessing:

[0083] Obtain basic data on complex terrain, including but not limited to drawings, surveying and mapping data, and satellite images, and determine the initial area where complex terrain needs to be modeled through basic data;

[0084] Obtain the minimum rectangle containing the initial area as the standard area, and map the standard area to the horizontal plane to obtain the initial plane map;

[0085] Construct a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, and integrate the initial plane map into the coordinate system. For example, make a vertex of the standard area in the initial plane map coincide with the origin of the coordinate system, and make the two sides of the standard area coincide with the horizontal and vertical axes of the coordinate system, and then divide the initial plane map into several equal rectangular areas.

[0086] The above steps convert the modeling of complex terrain into the modeling of multiple rectangular areas in the plane map, and integrate the plane map into a coordinate system with longitude and latitude as horizontal and vertical coordinates, which is more conducive to searching and data matching.

[0087] Modeling process:

[0088] The GIS data and elevation data of each rectangular area are obtained, and the initial three-dimensional model of each rectangular area is constructed. By converting the modeling of complex terrain into processing of multiple rectangular areas, the difficulty of data processing is reduced, and the modeling of multiple rectangular areas can be carried out simultaneously, thereby improving the modeling efficiency. However, the modeling of multiple rectangular areas separately needs to consider the phenomenon of incoordination during subsequent fusion. Therefore, this embodiment further provides a first method for correcting the three-dimensional models of adjacent rectangular areas. The first method includes:

[0089] Transition areas are preset around each rectangular area, and the transition area of ​​each rectangular area includes four overlapping areas and four non-overlapping areas;

[0090] Obtain an arbitrary rectangular area as a second rectangular area, and obtain a non-overlapping area in the second rectangular area as area E and an overlapping area as area F;

[0091] Obtain an adjacent non-overlapping area of ​​the area E and record it as area G, and count and calculate the average elevation value of the area E as the first elevation value, and the average elevation value of the area G as the second elevation value;

[0092] Calculate a first difference between the first elevation value and the second elevation value, and determine whether the first difference is less than a first threshold value. If not, do nothing. If yes, calculate an average value of the first elevation value and the second elevation value as a third elevation value. Based on the third elevation value, adjust the elevation values ​​of the area E and the area G, and complete the correction of the three-dimensional model corresponding to the area E and the area G.

[0093] Place the region F and all adjacent overlapping regions into a preset region set, and count and calculate the average elevation value of each region in the preset region set to obtain a calculation result;

[0094] Based on the calculation result, the difference between the average elevation values ​​corresponding to any two areas in the preset area set is calculated and recorded as the second difference, and it is determined whether all the second difference values ​​are less than the first threshold value. If so, the average of the average elevation values ​​of all areas in the preset area set is calculated and recorded as the fourth elevation value. Based on the fourth elevation value, the elevation values ​​of all areas in the preset area set are adjusted to complete the correction of the corresponding three-dimensional models of all areas in the preset area set. If not, no action is taken.

[0095] Among them, please refer to Figure 2 , Figure 2 is a schematic diagram of the transition area corresponding to the rectangular area in the present invention. It should be noted that Figure 2 The legends about overlapping and non-overlapping areas in the transition area are for illustrative purposes only. Figure 2 The rectangular area in is recorded as the second rectangular area. After the transition area is preset around the second rectangular area, the entire transition area will be divided into four overlapping areas and four non-overlapping areas, one of which is recorded as area E, and one overlapping area is recorded as F; the adjacent non-overlapping area of ​​area E is obtained and recorded as area G, and the difference between the average elevation values ​​of area E and area G is calculated to determine whether the difference is less than the first threshold value. If so, it means that the mountain types (including plains, hills, and mountains) between area E and area G are likely to be consistent. At this time, the average elevation value between the areas composed of area E and area G is calculated and recorded as the third elevation value. According to the third elevation value, the elevation values ​​of area E and area G are adjusted. If there is an elevation value in area E or area G that exceeds (or is lower than) the third elevation value by a certain amplitude, the exceeded elevation value is adjusted to the third elevation value. If not, it means that the mountain types between area E and area G are likely to be inconsistent, and no action is taken at this time. Similarly, the above method is also used to process the overlapping area F. The difference is that the adjacent areas of area F may be 1 or 3. Therefore, this embodiment is to place area F and the adjacent overlapping areas into a preset area set, and then calculate the second difference between the average elevation values ​​of any two areas in the preset area set, and determine whether all the second differences are less than the first threshold. If so, calculate the average of the average elevation values ​​of all areas in the preset area set as the fourth elevation value, and adjust the elevation values ​​of all areas in the preset area set based on the fourth elevation value. The adjustment method has been explained in the above embodiment. If not, no action is taken.

[0096] Texture processing:

[0097] Based on the aerial survey video stream of the standard area, multiple frames of aerial survey images of the standard area are obtained and corrected; a preset number of first feature points are determined in each rectangular area, and then the first feature points are used to match and search for the relative aerial survey image, and then the aerial survey images are integrated and cropped to obtain the first image of each rectangular area, and all the first images are mapped to the corresponding corrected three-dimensional model. However, when mapping all the first rectangular areas, there is also a phenomenon of incoordination in the subsequent fusion. Therefore, this embodiment also provides a second method for smoothing the first images of any two adjacent rectangular areas. The second method includes:

[0098] Obtaining first images corresponding to any two adjacent rectangular areas and recording them as second images and third images respectively;

[0099] Determine whether there is an overlapping area between the second image and the third image, if not, do not take any action, if yes, obtain the initial pixel value of each pixel in the overlapping area, assign a weight value to each pixel in the overlapping area using the first formula to obtain an assignment result, and based on the assignment result, use the second formula to calculate the initial pixel value of each pixel in the overlapping area to obtain a corresponding fused pixel value;

[0100] Based on the fused pixel value of each pixel point in the overlapping area, a smoothing process is performed on the overlapping area of ​​the second image and the third image.

[0101] The first formula is:

[0102]

[0103] δ 1 is the weight value of a single pixel in the overlapping area in the second image, δ 2 is the weight value of a single pixel point in the overlapping area in the third image, d 1 is the distance between a single pixel point in the overlapping area and the center point of the second image, d 2 is the distance between a single pixel point in the overlapping area and the center point of the third image, and B is a constant.

[0104] The second formula is:

[0105] W ′ =δ 1 ×W 1 +δ 2 ×W 2

[0106] W ′ is the fused pixel value of a single pixel in the overlapping area, W 1is the initial pixel value of a single pixel point in the overlapping area in the second image, W 2 is the initial pixel value of a single pixel point in the overlapping area in the third image.

[0107] Among them, based on the aerial survey image and the first feature point in each rectangular area, processing is performed to obtain the first image of each rectangular area, and all the first images are mapped to the corresponding modified three-dimensional model. However, when mapping, the phenomenon of overlapping areas between adjacent rectangular areas cannot be avoided. Therefore, this embodiment determines whether there is an overlapping area between the second image and the third image. If not, no action is taken. If so, a corresponding weight value is assigned to each pixel in the overlapping area through the first formula, and the initial pixel value of each pixel in the overlapping area is obtained. The initial pixel value of each pixel in the overlapping area is calculated by the second formula to obtain the fused pixel value of a single pixel in the overlapping area, thereby achieving a smooth transition between adjacent images.

[0108] Finally, after modeling preprocessing, modeling processing and mapping processing, a standard three-dimensional model of complex terrain is generated, which ensures the accuracy of the three-dimensional model while improving the modeling efficiency.

[0109] Furthermore, this embodiment also provides a method for optimizing a complex terrain three-dimensional model, including:

[0110] Obtaining the first image of each rectangular area and processing it to obtain a corresponding binary image;

[0111] Obtaining a first ratio between the area of ​​the shadow region in each binary image and the area of ​​the corresponding binary image to obtain a first acquisition result;

[0112] Based on the first acquisition result, different rectangular areas are graded, and the grade of the rectangular area is proportional to the corresponding first ratio;

[0113] Acquire all aerial survey images of the complex terrain within a preset time period to obtain a second acquisition result, and based on the second acquisition result, process all first images of each rectangular area and put them into a first data set;

[0114] Based on the level of each rectangular area, selecting a corresponding number of second feature points in each rectangular area, where the number of the second feature points is proportional to the level of the corresponding rectangular area;

[0115] Obtaining the pixel points contained in all the second feature points in each rectangular area, and based on the corresponding first data set, processing to obtain a change curve of the pixel points corresponding to each second feature point in each rectangular area, to obtain a second processing result;

[0116] Based on the second processing result, within the preset time period, the pixel points corresponding to each second feature point in each rectangular area are updated to complete the optimization of the standard three-dimensional model.

[0117] The first ratio is calculated by the third formula:

[0118]

[0119] α n is the first ratio, A n is the shadow area in the binary image, S n is the area of ​​the binary image.

[0120] Based on the first acquisition result, classifying different rectangular areas into different levels includes:

[0121] Acquire historical data of all first ratios, divide the first ratios into data intervals based on the historical data, and assign a corresponding grade value to each data interval;

[0122] Obtain an arbitrary rectangular area as a first rectangular area, and obtain a first ratio of the first rectangular area as a second ratio;

[0123] The data interval corresponding to the second ratio is obtained as a first data interval;

[0124] The level corresponding to the first data interval is obtained as the level of the first rectangular area.

[0125] Obtain a first ratio of an arbitrary rectangular area and record it as a second ratio, and obtain a data interval corresponding to the second ratio and record it as a first data interval;

[0126] The level value corresponding to the first data interval is obtained as the level of the first rectangular area.

[0127] Among them, this embodiment obtains and processes the binary image of each rectangular area, calculates the ratio of the shadow area area to the entire image area in each binary image, and classifies each rectangular area into levels. The coverage ratio of vegetation and the like in each rectangular area is determined by the level, and then a corresponding number of feature points are selected based on the level of each rectangular area. The larger the vegetation coverage area, the higher the level of the rectangular area, and the more corresponding feature points are selected. Then, a change curve of the pixel points included in the feature points within a preset time period is obtained, and the feature points included in each rectangular area are updated based on the corresponding change curve. For complex terrain, if the entire three-dimensional model is to be updated in real time, the amount of data that needs to be processed will be massive. This example selects different numbers of feature points in different rectangular areas, and updates the selected feature points to achieve the effect of updating the entire standard three-dimensional model of complex terrain within a preset time period, thereby further improving the authenticity of three-dimensional modeling of complex terrain.

[0128] Embodiment 2

[0129] Please refer to Figure 3 , Figure 3 1 is a schematic diagram of a complex terrain modeling system in the present invention, the system comprising:

[0130] An initial area unit is used to obtain basic data of complex terrain and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data;

[0131] A mapping unit, used for obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map;

[0132] A coordinate system unit, used to construct a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrate the initial plane map into the coordinate system, and divide the initial plane map into a plurality of equal rectangular areas;

[0133] The initial three-dimensional model unit is used to obtain the GIS data and elevation data of each rectangular area and construct an initial three-dimensional model of each rectangular area;

[0134] A correction unit, configured to correct the initial three-dimensional models of any two adjacent rectangular areas by using a first method to obtain a correction result, and obtain a corrected three-dimensional model of each rectangular area based on the correction result;

[0135] A mapping unit is used to obtain the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, obtain a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model;

[0136] A smoothing processing unit, used for performing smoothing processing on the first image of any two adjacent rectangular areas by using a second method to obtain a first processing result;

[0137] A standard three-dimensional model unit is used to generate a standard three-dimensional model of the complex terrain based on the first processing result.

[0138] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0139] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A complex terrain modeling method, characterized in that: The method comprises the following steps: Acquire basic data of complex terrain, and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data; Obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map; Constructing a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrating the initial plane map into the coordinate system, and dividing the initial plane map into a plurality of equal rectangular areas; Obtain GIS data and elevation data for each rectangular area and construct an initial three-dimensional model for each rectangular area; Using the first method to correct the initial three-dimensional models of any two adjacent rectangular areas to obtain a correction result, and based on the correction result, obtaining a corrected three-dimensional model of each rectangular area; Acquire the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, acquire a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model; Using the second method to perform smoothing processing on the first image of any two adjacent rectangular areas to obtain a first processing result; Based on the correction result and the first processing result, a standard three-dimensional model of the complex terrain is generated.

2. A complex terrain modeling method according to claim 1, characterized in that: The first method comprises: Transition areas are preset around each rectangular area, and the transition area of ​​each rectangular area includes four overlapping areas and four non-overlapping areas; Obtain an arbitrary rectangular area as a second rectangular area, and obtain a non-overlapping area in the second rectangular area as area E and an overlapping area as area F; Obtain an adjacent non-overlapping area of ​​the area E and record it as area G, and count and calculate the average elevation value of the area E as the first elevation value, and the average elevation value of the area G as the second elevation value; Calculate a first difference between the first elevation value and the second elevation value, and determine whether the first difference is less than a first threshold value. If not, do nothing. If yes, calculate an average value of the first elevation value and the second elevation value as a third elevation value. Based on the third elevation value, adjust the elevation values ​​of the area E and the area G, and complete the correction of the three-dimensional model corresponding to the area E and the area G. Place the region F and all adjacent overlapping regions into a preset region set, and count and calculate the average elevation value of each region in the preset region set to obtain a calculation result; Based on the calculation result, the difference between the average elevation values ​​corresponding to any two areas in the preset area set is calculated and recorded as the second difference, and it is determined whether all the second difference values ​​are less than the first threshold value. If so, the average of the average elevation values ​​of all areas in the preset area set is calculated and recorded as the fourth elevation value. Based on the fourth elevation value, the elevation values ​​of all areas in the preset area set are adjusted to complete the correction of the corresponding three-dimensional models of all areas in the preset area set. If not, no action is taken.

3. A complex terrain modeling method according to claim 1, characterized in that: The second method comprises: Obtaining first images corresponding to any two adjacent rectangular areas and recording them as second images and third images respectively; Determine whether there is an overlapping area between the second image and the third image, if not, do not take any action, if yes, obtain the initial pixel value of each pixel in the overlapping area, and assign a weight value to each pixel in the overlapping area using the first formula to obtain an assignment result, and based on the assignment result, use the second formula to calculate the initial pixel value of each pixel in the overlapping area to obtain a corresponding fused pixel value; Based on the fused pixel value of each pixel point in the overlapping area, a smoothing process is performed on the overlapping area of ​​the second image and the third image.

4. A complex terrain modeling method according to claim 3, characterized in that: The first formula is: δ1 is the weight value of a single pixel point in the overlapping area in the second image, δ2 is the weight value of a single pixel point in the overlapping area in the third image, d1 is the distance between a single pixel point in the overlapping area and the center point of the second image, d2 is the distance between a single pixel point in the overlapping area and the center point of the third image, and B is a constant.

5. A complex terrain modeling method according to claim 4, characterized in that: The second formula is: IN ′ =δ1×W1+δ2×W2 W ′ is the fused pixel value of a single pixel in the overlapping area, W1 is the initial pixel value of a single pixel in the overlapping area in the second image, and W2 is the initial pixel value of a single pixel in the overlapping area in the third image.

6. A complex terrain modeling method according to claim 1, characterized in that: The method further comprises optimizing the standard three-dimensional model: Obtaining the first image of each rectangular area and processing it to obtain a corresponding binary image; Obtaining a first ratio between the area of ​​the shadow region in each binary image and the area of ​​the corresponding binary image to obtain a first acquisition result; Based on the first acquisition result, different rectangular areas are graded, and the grade of the rectangular area is proportional to the corresponding first ratio; Acquire all aerial survey images of the complex terrain within a preset time period to obtain a second acquisition result, and based on the second acquisition result, process all first images of each rectangular area and put them into a first data set; Based on the level of each rectangular area, selecting a corresponding number of second feature points in each rectangular area, where the number of the second feature points is proportional to the level of the corresponding rectangular area; Obtaining the pixel points contained in all the second feature points in each rectangular area, and based on the corresponding first data set, processing to obtain a change curve of the pixel points corresponding to each second feature point in each rectangular area, to obtain a second processing result; Based on the second processing result, within the preset time period, the pixel points corresponding to each second feature point in each rectangular area are updated to complete the optimization of the standard three-dimensional model.

7. A complex terrain modeling method according to claim 6, characterized in that: The first ratio is calculated by the third formula: α n is the first ratio, A n is the shadow area in the binary image, S n is the area of ​​the binary image.

8. A complex terrain modeling method according to claim 6, characterized in that: Based on the first acquisition result, classifying different rectangular areas into different levels includes: Acquire historical data of all first ratios, divide the first ratios into data intervals based on the historical data, and assign a corresponding grade value to each data interval; Obtain an arbitrary rectangular area as a first rectangular area, and obtain a first ratio of the first rectangular area as a second ratio; The data interval corresponding to the second ratio is obtained as a first data interval; Acquire the level corresponding to the first data interval as the level of the first rectangular area; Obtaining a first ratio of an arbitrary rectangular area as a second ratio, and obtaining a data interval corresponding to the second ratio as a first data interval; The level value corresponding to the first data interval is obtained as the level of the first rectangular area.

9. A complex terrain modeling method according to claim 1, characterized in that: Acquiring and processing the aerial survey images of the standard area includes: based on the aerial survey video stream of the standard area, acquiring multiple frames of aerial survey images of the standard area and performing correction processing.

10. A complex terrain modeling system, characterized in that: The system comprises: An initial area unit is used to obtain basic data of complex terrain and determine an initial area of ​​the complex terrain that needs to be modeled based on the basic data; A mapping unit, used for obtaining a minimum rectangle containing the initial area as a standard area, and mapping the standard area to a horizontal plane to obtain an initial plane map; A coordinate system unit, used to construct a coordinate system with latitude as the horizontal coordinate and longitude as the vertical coordinate, integrate the initial plane map into the coordinate system, and divide the initial plane map into a plurality of equal rectangular areas; The initial three-dimensional model unit is used to obtain the GIS data and elevation data of each rectangular area and construct an initial three-dimensional model of each rectangular area; A correction unit, configured to correct the initial three-dimensional models of any two adjacent rectangular areas by using a first method to obtain a correction result, and obtain a corrected three-dimensional model of each rectangular area based on the correction result; A mapping unit is used to obtain the aerial survey image of the standard area and process it to obtain a processing result, determine a preset number of first feature points in each rectangular area, obtain a first image corresponding to each rectangular area based on the processing result and all the first feature points of each rectangular area, and map each first image to the corresponding corrected three-dimensional model; A smoothing processing unit, used for performing smoothing processing on the first image of any two adjacent rectangular areas by using a second method to obtain a first processing result; A standard three-dimensional model unit is used to generate a standard three-dimensional model of the complex terrain based on the first processing result.

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