Generation method and device of digital elevation model (DEM)

Abstract

The invention relates to a method and a device for generating a digital elevation model (DEM). The method comprises the steps of determining a plurality of first target points of each row in a digital surface model DSM based on the digital surface model DSM; performing interpolation processing of a second target point between any two adjacent first target points based on the plurality of first target points of each row to obtain a plurality of ground points of each row; wherein the ground point comprises a first target point or a second target point; and performing elevation value assignment processing of a virtual point between any two adjacent ground points based on the plurality of ground points in each row, and generating a digital elevation model (DEM). According to the scheme, the digital elevation model DEM can be automatically and efficiently extracted from the digital surface model DSM, the precision of the digital elevation model DEM is high, the effect of removing non-ground targets is good, and the gentle slope effect and the cliff effect are well reserved.

Description

Technical Field

[0001] The present application relates to the field of surveying and mapping, and in particular to a method and device for generating a digital elevation model (DEM). Background Art

[0002] In related technologies, the Digital Surface Model (DSM) is a ground elevation model that includes the heights of buildings, bridges, and trees on the ground. The Digital Elevation Model (DEM) is a digital simulation of the ground terrain (i.e., a digital expression of the terrain surface morphology) using limited terrain elevation data. It is a physical ground model that represents the ground elevation in the form of a set of ordered numerical arrays. The Digital Elevation Model (DEM) is an important data for studying and analyzing terrain, watersheds, and identifying land objects.

[0003] At present, the main method for obtaining digital elevation model DEM is filtering method, such as cloth filtering algorithm, morphological filtering algorithm, progressive triangulation filtering algorithm, etc., which simulates and distinguishes ground points and non-ground points through different mathematical and physical models. However, the filtering method cannot overcome the problem of terrain complexity and it is difficult to distinguish ground points and non-ground points, which leads to errors in the obtained digital elevation model DEM and poor accuracy. Summary of the invention

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a method and device for generating a digital elevation model DEM, which can automatically and efficiently extract a digital elevation model DEM from a digital surface model DSM, and the digital elevation model DEM has high accuracy, good effect of removing non-ground targets and well retains the gentle slope effect and cliff effect.

[0005] The first aspect of the present application provides a method for generating a digital elevation model (DEM). The flying car includes a flying body and a land body. The method includes: based on the digital surface model (DSM), determining multiple first target points in each row of the digital surface model (DSM); based on the multiple first target points in each row, interpolating the second target point between any two adjacent first target points to obtain multiple ground points in each row; wherein the ground point includes the first target point or the second target point; based on the multiple ground points in each row, assigning the elevation value of the virtual point between any two adjacent ground points, and generating the digital elevation model (DEM).

[0006] In some embodiments, determining a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM includes: determining a plurality of first target points in each row of the digital surface model DSM according to a preset scale value based on the digital surface model DSM.

[0007] In some embodiments, based on the digital surface model DSM, according to a preset scale value, multiple first target points in each row of the digital surface model DSM are determined, including: based on the digital surface model DSM, according to a preset scale value, multiple third target points in each row of the digital surface model DSM are determined; for each third target point, the elevation values ​​of all virtual points within a preset range around the third target point are determined; and the virtual point corresponding to the lowest elevation value is used as the first target point.

[0008] In some embodiments, based on the digital surface model DSM, multiple first target points in each row of the digital surface model DSM are determined, including: based on the digital surface model DSM, determining the elevation value of any virtual point in each row of the digital surface model DSM; determining the corresponding mode based on the elevation value of any virtual point in each row, and using the elevation value corresponding to the mode as the ground value; based on the ground value, determining a fourth target point in any virtual point whose elevation value and ground value are less than a first threshold, and using the fourth target point as the first target point.

[0009] In some embodiments, interpolation processing of a second target point is performed between any two adjacent first target points to obtain multiple ground points in each row, including: using an N-ary tree traversal method, based on the height difference between any two adjacent first target points, when the height difference is greater than a second threshold, determining a virtual line and any virtual point between two adjacent first target points; determining the spatial vertical distance between each virtual point and the virtual line; taking the virtual point with the largest spatial vertical distance as the second target point to interpolate the second target point to obtain multiple ground points in each row.

[0010] In some embodiments, interpolation processing of a second target point is performed between any two adjacent first target points to obtain multiple ground points in each row, and the method also includes: using an N-ary tree traversal method, based on the height difference and distance difference between any two adjacent first target points, when the height difference is less than a second threshold and the distance difference is greater than a third threshold, determining a virtual line and any virtual point between two adjacent first target points; determining the spatial vertical distance between each virtual point and the virtual line; and taking the virtual point with the smallest spatial vertical distance as the second target point to interpolate the second target point to obtain multiple ground points in each row.

[0011] In some embodiments, the N-ary tree traversal method includes a level-order traversal of the N-ary tree, a pre-order traversal of the N-ary tree, or a post-order traversal of the N-ary tree.

[0012] In some embodiments, the elevation values ​​of virtual points are assigned between any two adjacent ground points, and a digital elevation model DEM is generated, including: determining a corresponding linear equation based on any two adjacent ground points; assigning the elevation values ​​of virtual points according to the linear equation, and generating a digital elevation model DEM.

[0013] In some embodiments, the method further includes: based on the digital elevation model DEM, when it is determined that the digital elevation model DEM includes non-ground points, adjusting the predetermined scale value to obtain a new digital elevation model DEM generated according to a new predetermined scale value; wherein the new digital elevation model DEM does not include non-ground points.

[0014] According to a second aspect of the present application, there is provided a device for generating a digital elevation model (DEM), the device comprising: a determination module for determining a plurality of first target points in each row of the digital surface model (DSM) based on the digital surface model (DSM); an interpolation processing module for performing interpolation processing of second target points between any two adjacent first target points based on the plurality of first target points in each row, to obtain a plurality of ground points in each row; wherein the ground points include first target points or second target points; and a generation module for performing elevation value assignment processing of virtual points between any two adjacent ground points based on the plurality of ground points in each row, and generating the digital elevation model (DEM).

[0015] A third aspect of the present application provides an electronic device, including: Processor; and The memory stores executable codes thereon, and when the executable codes are executed by the processor, the processor is caused to execute the method as described above.

[0016] A fourth aspect of the present application provides a computer-readable storage medium having executable code stored thereon. When the executable code is executed by a processor of an electronic device, the processor is caused to execute the method as described above.

[0017] The technical solution provided by the present application may include the following beneficial effects: it can automatically and efficiently extract a digital elevation model DEM from a digital surface model DSM, and the digital elevation model DEM has high accuracy, good effect of removing non-ground targets and good retention of gentle slope effects and cliff effects.

[0018] The technical solution of the present application can also: completely eliminate non-ground targets without relying on classification data.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail the exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0021] Figure 1 It is a schematic diagram of a process of generating a digital elevation model DEM shown in an embodiment of the present application; Figure 2 It is another schematic diagram of the process of generating a digital elevation model DEM shown in an embodiment of the present application; Figure 3 It is a structural schematic diagram of a device for generating a digital elevation model DEM shown in an embodiment of the present application; Figure 4 It is a schematic diagram of the structure of an electronic device shown in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0023] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0024] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0025] Methods for obtaining digital elevation model (DEM) include filtering, region growing, and classification-based methods. However, the defect of filtering methods is that they cannot overcome the complexity of terrain. In complex terrain (such as mountains, hills, cities, etc.), filtering algorithms are difficult to accurately distinguish between ground points and non-ground points, resulting in errors in DEM, and strong dependence on parameters. The region growing method uses the continuity and spatial correlation between ground points in the digital surface model (DSM) data to select initial seed points and merge pixels with similar properties into a ground point set according to certain growth criteria and termination conditions, thereby generating a digital elevation model (DEM). Although the region growing algorithm is insensitive to the selection order and position of the initial seed points, the quality of the initial seed points will directly affect the final result of the algorithm. Classification-based methods mainly use random forests or deep learning methods to automatically extract and classify high-dimensional features to analyze non-ground and ground areas. However, classification-based methods rely too much on classification results.

[0026] It can be seen that there are still difficulties in extracting high-precision digital elevation models (DEMs) from digital surface models (DSMs). The main reason is that there is no obvious difference between terrain features and ground features. For example, the features of large-scale buildings and ground features are close to each other in some areas; cliffs, karst landforms, mountains and buildings have similar features. As a result, there are problems in obtaining digital elevation models (DEMs) from digital surface models (DSMs) such as incomplete removal of building areas and loss of information on small slope areas.

[0027] In response to the above problems, an embodiment of the present application provides a method for generating a digital elevation model DEM, which can automatically and efficiently extract a digital elevation model DEM from a digital surface model DSM, and the digital elevation model DEM has high accuracy, good effect of removing non-ground targets and well retains the gentle slope effect and cliff effect.

[0028] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0029] Figure 1 It is a flowchart of a method for generating a digital elevation model DEM shown in an embodiment of the present application.

[0030] See also Figure 1 A method for generating a digital elevation model (DEM), wherein the flying vehicle comprises a flying body and a land body, and the method comprises: Step 101 : determining a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM.

[0031] In this step, a random point in each row of the digital surface model DSM, ie, a first target point, may be obtained by setting a fixed scale value, thereby obtaining a plurality of first target points.

[0032] In this step, the elevation value of any virtual point in each row can also be calculated based on the digital surface model DSM, so as to obtain the corresponding mode of the elevation value of any virtual point in each row, and then the elevation value corresponding to the mode is used as the ground value. Then, all points in the arbitrary virtual point whose elevation value and the ground value are less than the first threshold are used as the first target point.

[0033] In some embodiments, determining a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM may include: determining a plurality of first target points in each row of the digital surface model DSM according to a preset scale value based on the digital surface model DSM. For example, the preset scale value may be set to 500 meters or 1,000 meters, etc., and then taking a point at a fixed distance of 500 meters or 1,000 meters as the first target point.

[0034] In some embodiments, determining multiple first target points in each row of the digital surface model DSM based on the digital surface model DSM may include: determining the elevation value of any virtual point in each row of the digital surface model DSM based on the digital surface model DSM; determining the corresponding mode based on the elevation value of any virtual point in each row, and using the elevation value corresponding to the mode as the ground value; based on the ground value, determining a fourth target point in any virtual point whose elevation value and ground value are less than a first threshold, and using the fourth target point as the first target point.

[0035] For example, 100 arbitrary virtual points are randomly selected, and the corresponding elevation values ​​are obtained. After calculation, it is determined that the elevation value belonging to the majority is 20 meters; the first threshold is set to 5 meters, and the points with elevation values ​​between 15 meters and 25 meters are taken as the first target points.

[0036] On the basis of the above embodiment, further, based on the digital surface model DSM, according to a preset scale value, determining multiple first target points in each row of the digital surface model DSM may include: based on the digital surface model DSM, according to a preset scale value, determining multiple third target points in each row of the digital surface model DSM; for each third target point, determining the elevation values ​​of all virtual points within a preset range around the third target point; and taking the virtual point corresponding to the lowest elevation value as the first target point.

[0037] For example, the point obtained according to the preset scale value is used as the third target point, and with the third target point as the center, a virtual point corresponding to the lowest elevation value within a preset range around it is selected as the target point, thereby obtaining the first target point.

[0038] For example, a convolution kernel matrix is ​​used to obtain a first target point from a number of virtual points, and the matrix includes the elevation value of each point, and the corresponding lowest value is used as the first target point. This is conducive to improving the quality of the first target point, and further conducive to generating a high-precision digital elevation model DEM.

[0039] Step 102, based on the multiple first target points in each row, interpolation processing of the second target point is performed between any two adjacent first target points to obtain multiple ground points in each row; wherein the ground points include the first target points or the second target points.

[0040] In this step, interpolation processing of the second target point can be performed between any two adjacent first target points to insert a plurality of second target points, thereby obtaining a plurality of ground points in each row.

[0041] In this step, multiple ground points in each row may be obtained by an N-ary tree traversal method, wherein the N-ary tree traversal method may include a level-order traversal of the N-ary tree, a pre-order traversal of the N-ary tree, or a post-order traversal of the N-ary tree.

[0042] It can be understood that the use of the N-ary tree traversal method for loop iteration can quickly insert multiple second target points, which is conducive to quickly obtaining a high-precision digital elevation model DEM from the digital surface model DSM.

[0043] Step 103 , based on the multiple ground points in each row, the elevation value of the virtual point is assigned between any two adjacent ground points, and a digital elevation model DEM is generated.

[0044] In this step, the elevation value is assigned, and after the assignment, the digital elevation model DEM can be generated.

[0045] In some embodiments, performing elevation value assignment processing of virtual points between any two adjacent ground points and generating a digital elevation model DEM may include: determining a corresponding linear equation based on any two adjacent ground points; performing elevation value assignment processing of virtual points according to the linear equation and generating a digital elevation model DEM.

[0046] It can be understood that by connecting two adjacent ground points, a linear equation matching the line can be obtained, such as a first-order equation such as x+y=b1 or 2x-y=b2 or x-2y=b3.

[0047] Linear interpolation is performed according to the linear equation, that is, the elevation value of the virtual point is assigned. Among them, linear fitting interpolation is performed for any two adjacent ground points, and interpolation methods such as bilinear fitting or bicubic fitting interpolation can be used.

[0048] The method for generating a digital elevation model DEM in the embodiment of the present application can automatically and efficiently extract a digital elevation model DEM from a digital surface model DSM, and the digital elevation model DEM has high accuracy, good effect of removing non-ground targets, and well preserves the gentle slope effect and cliff effect.

[0049] In some embodiments, the method for generating the digital elevation model DEM may further include: based on the digital elevation model DEM, when it is determined that the digital elevation model DEM includes non-ground points, adjusting the predetermined scale value to obtain a new digital elevation model DEM generated according to the new predetermined scale value; wherein the new digital elevation model DEM does not include non-ground points.

[0050] It is understandable that there may be non-ground points in the generated digital elevation model DEM. For example, when a selected first target point is located just above a building, it is easy to cause non-ground points to exist in the generated digital elevation model DEM.

[0051] In order to completely remove non-ground targets, the predetermined scale value can be adjusted, and then the second target point interpolation processing and elevation value assignment processing are performed in sequence, so as to avoid the situation where the building is not removed.

[0052] The method for generating a digital elevation model DEM in an embodiment of the present application can obtain a new digital elevation model DEM generated according to a new predetermined scale value by adjusting the predetermined scale value. The new digital elevation model DEM does not include non-ground points, thereby completely removing non-ground targets.

[0053] In some embodiments, interpolation processing of a second target point is performed between any two adjacent first target points to obtain multiple ground points in each row, which may include: using an N-ary tree traversal method, based on the height difference between any two adjacent first target points, when the height difference is greater than a second threshold, determining a virtual line and any virtual point between two adjacent first target points; determining the spatial vertical distance between each virtual point and the virtual line; and taking the virtual point with the largest spatial vertical distance as the second target point to interpolate the second target point to obtain multiple ground points in each row.

[0054] It can be understood that the height difference threshold, i.e., the second threshold, is first set to obtain the elevation values ​​of the two adjacent points to obtain the height difference between the two points. When the height difference is greater than the second threshold, a virtual line is established between the two points. Taking the virtual line as a reference, the spatial vertical distance between each virtual point and the virtual line is determined, that is, a virtual vertical line can be drawn in the vertical direction with the virtual point as the origin, and the distance between the virtual vertical line and the virtual line is the spatial vertical distance between the virtual point and the virtual line. Since the elevation values ​​of different virtual points are different, the spatial vertical distances between different virtual points and the virtual line are different, and the virtual point with the largest spatial vertical distance can be selected as the second target point. Repeat this cycle until all points are traversed.

[0055] The method for generating a digital elevation model DEM in an embodiment of the present application, under the above conditions, obtains multiple ground points in each row by taking the virtual point with the largest spatial vertical distance as the second target point to perform interpolation processing on the second target point, and can obtain high-quality ground points, which is conducive to obtaining a high-precision digital elevation model DEM, while having a better effect of clearing non-ground targets and well retaining the gentle slope effect and cliff effect.

[0056] In some embodiments, interpolation processing of a second target point is performed between any two adjacent first target points to obtain multiple ground points in each row, and it may also include: using an N-ary tree traversal method, based on the height difference and distance difference between any two adjacent first target points, when the height difference is less than a second threshold and the distance difference is greater than a third threshold, determining a virtual line and any virtual point between two adjacent first target points; determining the spatial vertical distance between each virtual point and the virtual line; taking the virtual point with the smallest spatial vertical distance as the second target point to interpolate the second target point to obtain multiple ground points in each row.

[0057] It can be understood that the height difference threshold, i.e., the second threshold, and the distance difference threshold, i.e., the third threshold, are first set. The elevation values ​​of the two adjacent points are obtained, the height difference between the two points is obtained, and the distance difference between the two points is obtained. When the height difference is less than the second threshold and the distance difference is greater than the third threshold, a virtual line is established between the two points. Taking the virtual line as a reference, the spatial vertical distance between each virtual point and the virtual line is determined, that is, a virtual vertical line can be drawn in the vertical direction with the virtual point as the origin, and the distance between the virtual vertical line and the virtual line is the spatial vertical distance between the virtual point and the virtual line. Since the elevation values ​​of different virtual points are different, the spatial vertical distances between different virtual points and the virtual line are different, and the virtual point with the smallest spatial vertical distance can be selected as the second target point. This cycle is repeated until all points are traversed.

[0058] The method for generating the digital elevation model DEM of the embodiment of the present application, under the above conditions, obtains multiple ground points in each row by taking the virtual point with the smallest spatial vertical distance as the second target point to perform interpolation processing on the second target point, and can obtain high-quality ground points, which is conducive to obtaining a high-precision digital elevation model DEM, while having a better effect of clearing non-ground targets and well retaining the gentle slope effect and cliff effect.

[0059] In order to better understand the present application, the content of the present application is further explained below in conjunction with the embodiments, but the present application is not limited to the following embodiments.

[0060] Figure 2 It is another flowchart of the method for generating a digital elevation model DEM shown in an embodiment of the present application.

[0061] See also Figure 2 , in operation 210 , a digital surface model is obtained.

[0062] In operation 220, the first target point is obtained row by row, for example, by setting a fixed scale value to obtain random points in each row, that is, the first target point.

[0063] In operation 230, the height difference of adjacent points is judged row by row, or the height difference and the distance difference is judged, for example, by using an N-ary tree traversal method.

[0064] In operation 240, it is determined whether the height difference is greater than the height difference threshold. If yes, in operation 250, the virtual point with the largest spatial vertical distance is used as the second target point, the second target point is interpolated, and the height difference determination of adjacent points, or the height difference and distance difference determination, is continued row by row.

[0065] If not, it is determined whether the distance difference is greater than the distance difference threshold in operation 260. If yes, it is determined in operation 270 that the virtual point with the smallest vertical distance in space is used as the second target point, the second target point is interpolated, and the height difference determination of the adjacent points, or the height difference and distance difference determination, is continued row by row.

[0066] In the case of no, a plurality of ground points of each row are obtained in operation 280. For example, the first target point and the second target points inserted in all traversal processes are output.

[0067] In operation 290 , based on the plurality of ground points in each row, an elevation value assignment process of a virtual point is performed between any two adjacent ground points, and a digital elevation model DEM is generated.

[0068] In operation 2100, it is determined whether the digital elevation model DEM includes non-ground points. If yes, in operation 2110, the scale value is changed, and the first target point is taken row by row according to the new scale value, and the interpolation processing and elevation value assignment processing of the second target point are performed.

[0069] If no, a target digital elevation model DEM is output in operation 2120. The target digital elevation model DEM does not include non-ground points.

[0070] The multi-scale iterative N-ary tree traversal interpolation proposed in this embodiment obtains terrain, which can retain the cliff characteristics of terrain slope and obtain smooth terrain. This embodiment uses a row-by-row N-ary tree traversal to obtain corresponding ground points. The ground points obtained in this way do not need to rely on other classified data. The method is simple. The ground points obtained rely on the ground point information within a certain distance before and after and the height information around the point. The calculation time is short and the accuracy is high. The iterative optimization method is used to clear the non-ground area of ​​the acquired digital elevation model DEM data, which can solve the problem that conventional terrain acquisition methods cannot clear large buildings and vegetation.

[0071] Corresponding to the aforementioned application function implementation method embodiment, the present application also provides a digital elevation model DEM generation device, electronic device and corresponding embodiments.

[0072] Figure 3 It is a structural schematic diagram of a device for generating a digital elevation model DEM shown in an embodiment of the present application.

[0073] See also Figure 3 The digital elevation model DEM generation device 300 of this embodiment includes a determination module 310, an interpolation processing module 320 and a generation module 330.

[0074] The determination module 310 is configured to determine a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM.

[0075] The interpolation processing module 320 is used to perform interpolation processing of the second target point between any two adjacent first target points based on the multiple first target points in each row, so as to obtain multiple ground points in each row; wherein the ground points include the first target points or the second target points; The generating module 330 is used to perform elevation value assignment processing of virtual points between any two adjacent ground points based on the multiple ground points in each row, and generate a digital elevation model DEM.

[0076] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0077] According to an embodiment of the present application, any multiple modules of the determination module 310, the interpolation processing module 320 and the generation module 330 can be combined into one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the determination module 310, the interpolation processing module 320 and the generation module 330 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware and firmware or in any appropriate combination of any of them. Alternatively, at least one of the determination module 310, the interpolation processing module 320 and the generation module 330 can be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding function can be performed.

[0078] Figure 4 It is a schematic diagram of the structure of an electronic device shown in an embodiment of the present application.

[0079] See also Figure 4 , the electronic device 400 includes a memory 410 and a processor 420.

[0080] The processor 420 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0081] The memory 410 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage devices. Among them, ROM can store static data or instructions required by the processor 420 or other modules of the computer. The permanent storage device may be a readable and writable storage device. The permanent storage device may be a non-volatile storage device that does not lose the stored instructions and data even after the computer is powered off. In some embodiments, the permanent storage device uses a large-capacity storage device (such as a magnetic or optical disk, flash memory) as a permanent storage device. In some other embodiments, the permanent storage device may be a removable storage device (such as a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as a dynamic random access memory. The system memory may store some or all instructions and data required by the processor at runtime. In addition, the memory 410 may include any combination of computer-readable storage media, including various types of semiconductor storage chips (such as DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and disks and / or optical disks may also be used. In some embodiments, the memory 410 may include a readable and / or writable removable storage device, such as a laser disc (CD), a read-only digital versatile disc (such as a DVD-ROM, a double-layer DVD-ROM), a read-only Blu-ray disc, an ultra-density optical disc, a flash memory card (such as an SD card, a mini SD card, a Micro-SD card, etc.), a magnetic floppy disk, etc. Computer-readable storage media do not include carrier waves and transient electronic signals transmitted wirelessly or wired.

[0082] The memory 410 stores executable codes, and when the executable codes are processed by the processor 420 , the processor 420 can execute part or all of the methods described above.

[0083] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0084] Alternatively, the present application can also be implemented as a computer-readable storage medium (or non-transitory machine-readable storage medium or machine-readable storage medium) on which executable code (or computer program or computer instruction code) is stored. When the executable code (or computer program or computer instruction code) is executed by a processor of an electronic device (or server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0085] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for generating a digital elevation model DEM, characterized in that: include: Based on the digital surface model DSM, determining a plurality of first target points in each row of the digital surface model DSM; Based on the multiple first target points in each row, interpolation processing of the second target point is performed between any two adjacent first target points to obtain multiple ground points in each row; wherein the ground points include the first target point or the second target point; Based on the multiple ground points in each row, the elevation value of the virtual point is assigned between any two adjacent ground points, and a digital elevation model DEM is generated.

2. The method according to claim 1, characterized in that The step of determining a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM comprises: Based on the digital surface model DSM, a plurality of first target points in each row of the digital surface model DSM are determined according to a preset scale value.

3. The method according to claim 2, characterized in that The determining, based on the digital surface model DSM and according to a preset scale value, a plurality of first target points in each row of the digital surface model DSM includes: Based on the digital surface model DSM, according to a preset scale value, determining a plurality of third target points in each row of the digital surface model DSM; For each of the third target points, determining the elevation values ​​of all virtual points within a preset range around the third target point; The virtual point corresponding to the lowest elevation value is used as the first target point.

4. The method according to claim 1, characterized in that: The step of determining a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM comprises: Based on the digital surface model DSM, determining the elevation value of any virtual point in each row of the digital surface model DSM; Determine a corresponding mode based on the elevation value of any virtual point in each row, and use the elevation value corresponding to the mode as a ground value; Based on the ground value, a fourth target point whose elevation value and the ground value are less than a first threshold value among the arbitrary virtual points is determined, and the fourth target point is used as the first target point.

5. The method according to claim 1, characterized in that Interpolation processing of the second target point is performed between any two adjacent first target points to obtain a plurality of ground points in each row, including: Adopting an N-ary tree traversal method, according to the height difference between any two adjacent first target points, when the height difference is greater than a second threshold, determining a virtual line between two adjacent first target points and any virtual point; Determine the spatial vertical distance between each virtual point and the virtual line; The virtual point with the largest vertical distance in the space is used as the second target point to perform interpolation processing on the second target point to obtain multiple ground points in each row.

6. The method according to claim 1, characterized in that Interpolation processing of a second target point is performed between any two adjacent first target points to obtain a plurality of ground points in each row, and further comprising: Adopting an N-ary tree traversal method, according to the height difference and the distance difference between any two adjacent first target points, when the height difference is less than a second threshold and the distance difference is greater than a third threshold, determining a virtual line and any virtual point between two adjacent first target points; Determine the spatial vertical distance between each virtual point and the virtual line; The virtual point with the smallest spatial vertical distance is used as the second target point to perform interpolation processing on the second target point to obtain multiple ground points in each row.

7. The method according to claim 5 or 6, characterized in that: The N-ary tree traversal method includes a level-order traversal of the N-ary tree, a pre-order traversal of the N-ary tree, or a post-order traversal of the N-ary tree.

8. The method according to claim 1, characterized in that Performing virtual point elevation value assignment processing between any two adjacent ground points and generating a digital elevation model DEM includes: Determine a corresponding linear equation based on any two adjacent ground points; The elevation value of the virtual point is assigned according to the linear equation, and a digital elevation model DEM is generated.

9. The method according to claim 2, characterized in that: The method further comprises: Based on the digital elevation model DEM, when it is determined that the digital elevation model DEM includes non-ground points, the predetermined scale value is adjusted to obtain a new digital elevation model DEM generated according to a new predetermined scale value; wherein the new digital elevation model DEM does not include non-ground points.

10. A device for generating a digital elevation model DEM, characterized in that: include: A determination module, configured to determine a plurality of first target points in each row of the digital surface model DSM based on the digital surface model DSM; An interpolation processing module, used for performing interpolation processing of second target points between any two adjacent first target points based on the multiple first target points in each row, to obtain multiple ground points in each row; wherein the ground points include the first target points or the second target points; The generating module is used to perform elevation value assignment processing of virtual points between any two adjacent ground points based on the multiple ground points in each row, and generate a digital elevation model DEM.

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