Methods, systems, smart terminals, and storage media for quantitative assessment of open spaces between three-dimensional buildings

Abstract

This application discloses a method, system, smart terminal, and storage medium for quantitative assessment of open space between three-dimensional buildings, relating to the field of data processing technology. The method includes: obtaining the minimum bounding box corresponding to a three-dimensional building model in three-dimensional space; obtaining observation point control parameters; generating three-dimensional observation viewpoints based on the minimum bounding box and observation point control parameters; generating a corresponding pushbroom point set on the surface of the three-dimensional building model using a pushbroom method, and removing invisible points to obtain a visible pushbroom point set composed of visible pushbroom points; calculating the building's visual field volume corresponding to each three-dimensional observation viewpoint based on the visible pushbroom set; obtaining the theoretical visual field volume corresponding to each three-dimensional observation viewpoint; and calculating the visual field volume openness index corresponding to each three-dimensional observation viewpoint based on the building's visual field volume and the theoretical visual field volume, using this as the result of the open space quantitative assessment. This application enables quantitative assessment of open space at specific spatial points.

Description

Technical Field

[0001] This application relates to the field of data processing technology, and in particular to a method, system, smart terminal and storage medium for quantitative assessment of open space between three-dimensional buildings. Background Technology

[0002] Currently, urban development models have shifted from scale expansion to stock renewal, making the quantification and evaluation of three-dimensional urban space increasingly important.

[0003] In existing technologies, methods for quantifying and evaluating 3D urban space typically use attributes related to 3D building data for characterization, such as urban volume, fractal dimension, building coverage, floor area ratio, average number of floors per building, and building density. The problem with existing technologies is that the existing attributes can only be used with a single building as the smallest unit of calculation, making it impossible to quantify and evaluate open space at specific spatial points.

[0004] Therefore, the relevant technologies still need to be improved and developed. Summary of the Invention

[0005] The main purpose of this application is to provide a method, system, smart terminal and storage medium for quantitative assessment of open space between three-dimensional buildings, which aims to solve the technical problem that the three-dimensional urban space quantification and assessment methods in related technologies can only use a building as the smallest calculation unit and cannot perform quantitative assessment of open space for specific spatial points.

[0006] To achieve the above objectives, the first aspect of this application provides a method for quantitatively evaluating open spaces between three-dimensional buildings, wherein the method includes:

[0007] Obtain the minimum bounding box corresponding to the 3D building model in 3D space;

[0008] Obtain the observation point control parameters. Based on the minimum bounding box and the observation point control parameters, generate a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model within the space defined by the minimum bounding box. The observation point control parameters include the total number of observation points and the maximum viewpoint height.

[0009] For each of the above three-dimensional observation viewpoints, a corresponding set of pushbroom points is generated on the surface of the above three-dimensional building model using the pushbroom method. The invisible points in the pushbroom point set are removed to obtain a set of visible pushbroom points.

[0010] The building visual volume corresponding to each of the above three-dimensional observation viewpoints is calculated based on the visual pushbroom set corresponding to each of the above three-dimensional observation viewpoints.

[0011] Obtain the theoretical field volume corresponding to each of the above three-dimensional observation viewpoints. Based on the building field volume and the theoretical field volume, calculate the field volume openness index corresponding to each of the above three-dimensional observation viewpoints and use it as the quantitative evaluation result of the open space corresponding to the above three-dimensional space. The field volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the above three-dimensional observation viewpoint.

[0012] Optionally, the above-mentioned observation point control parameters also include the observation point translation distance;

[0013] The aforementioned observation point translation distance is used to define the vertical translation distance of the aforementioned three-dimensional observation viewpoint each time during the generation of the aforementioned push-broom point set.

[0014] Optionally, the above-mentioned observation point control parameters also include the farthest line-of-sight distance, the maximum directional angle, and the observation point translation distance;

[0015] The above process of removing unseen points from the pushbroom point set yields a visible pushbroom point set consisting of visible pushbroom points, including:

[0016] Rays are emitted from the above three-dimensional observation viewpoints to all push points in the corresponding push point set, and push points that cannot be reached by the rays are regarded as unviewable points.

[0017] Calculate the azimuth angle of the above-mentioned push-broom point relative to the above-mentioned three-dimensional observation viewpoint, and take the push-broom point whose azimuth angle exceeds the above-mentioned maximum direction angle as an unseen point.

[0018] Calculate the Euclidean distance between the above three-dimensional observation viewpoint and the above push-broom point, and designate the points whose Euclidean distance exceeds the above farthest line-of-sight distance as unviewable points;

[0019] Delete all unseen points from the above pushbroom point set to obtain a visible pushbroom point set consisting of visible pushbroom points.

[0020] Optionally, the above calculation of the building field volume corresponding to each of the three-dimensional observation viewpoints based on the visible pushbroom set corresponding to each of the three-dimensional observation viewpoints includes: for any three-dimensional observation viewpoint, connecting all the visible pushbroom points corresponding to the three-dimensional observation viewpoint to obtain a visible pushbroom surface constructed by a triangular mesh;

[0021] Connect each of the above-mentioned triangular meshes in the above-mentioned visual push-broom surface with the above-mentioned three-dimensional observation viewpoint to obtain the visual field pyramids corresponding to each of the above-mentioned triangular meshes;

[0022] The building's visual field volume corresponding to the three-dimensional observation viewpoint is determined based on the volume of each of the aforementioned visible field pyramids.

[0023] Optionally, after calculating the field-of-view volume openness index corresponding to each of the three-dimensional observation viewpoints and using it as the quantitative evaluation result of the open space corresponding to the three-dimensional space, the method further includes:

[0024] The above-mentioned view volume openness index is interpolated based on a preset interpolation method to obtain the view volume openness index corresponding to multiple points to be solved in the above three-dimensional space.

[0025] The above quantitative assessment results of open space are updated based on the openness index of the field volume corresponding to the points to be solved.

[0026] Optionally, the aforementioned preset interpolation method includes radial basis interpolation.

[0027] Optionally, the above method further includes:

[0028] Based on the quantitative evaluation results of the open space corresponding to the above three-dimensional space, a quantitative map of the open space corresponding to the above three-dimensional space is generated. The quantitative map of the open space is used to visualize and output the openness index of the view volume corresponding to each point in the above three-dimensional space.

[0029] A second aspect of this application provides a quantitative assessment system for open spaces between three-dimensional buildings, wherein the system comprises:

[0030] The bounding box acquisition module is used to obtain the minimum bounding box corresponding to the 3D building model in 3D space;

[0031] The observation point generation module is used to obtain observation point control parameters and, based on the minimum bounding box and the observation point control parameters, generate a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model within the space defined by the minimum bounding box. The observation point control parameters include the total number of observation points and the maximum viewpoint height.

[0032] The pushbroom point generation module is used to generate a corresponding pushbroom point set on the surface of the three-dimensional building model for each of the above three-dimensional observation viewpoints using the pushbroom method, remove the invisible points in the pushbroom point set, and obtain a visible pushbroom point set composed of visible pushbroom points.

[0033] The first calculation module is used to calculate the building visual volume corresponding to each of the three-dimensional observation viewpoints based on the visual pushbroom set corresponding to each of the three-dimensional observation viewpoints.

[0034] The second calculation module is used to obtain the theoretical field volume corresponding to each of the above-mentioned three-dimensional observation viewpoints, and calculate the field volume openness index corresponding to each of the above-mentioned three-dimensional observation viewpoints based on the building field volume and the theoretical field volume, and use it as the quantitative evaluation result of the open space corresponding to the above-mentioned three-dimensional space. The field volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the above-mentioned three-dimensional observation viewpoint.

[0035] A third aspect of this application provides a smart terminal, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of any of the above-mentioned methods for quantitatively evaluating open space between three-dimensional buildings.

[0036] The fourth aspect of this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described methods for quantitatively evaluating open spaces between three-dimensional buildings.

[0037] As can be seen from the above, in this application, the minimum bounding box corresponding to the three-dimensional building model in three-dimensional space is obtained; the observation point control parameters are obtained, and based on the minimum bounding box and the observation point control parameters, a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model is generated within the space defined by the minimum bounding box. The observation point control parameters include the total number of observation points and the maximum viewpoint height. For each of the three-dimensional observation viewpoints, a corresponding pushbroom point set is generated on the surface of the three-dimensional building model using a pushbroom method. The invisible points in the pushbroom point set are removed to obtain a visible pushbroom point set composed of visible pushbroom points. The building view volume corresponding to each of the above-mentioned three-dimensional observation viewpoints is calculated based on the visual pushbroom set corresponding to each of the above-mentioned three-dimensional observation viewpoints; the theoretical view volume corresponding to each of the above-mentioned three-dimensional observation viewpoints is obtained; based on the building view volume and the theoretical view volume, the view volume openness index corresponding to each of the above-mentioned three-dimensional observation viewpoints is calculated and used as the quantitative evaluation result of the open space corresponding to the above-mentioned three-dimensional space. The view volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building view volume to the theoretical view volume corresponding to the above-mentioned three-dimensional observation viewpoint.

[0038] Compared with existing technologies, the open space quantification assessment method between three-dimensional buildings provided in this application generates three-dimensional observation viewpoints for the three-dimensional space and calculates the open space volume index corresponding to each three-dimensional observation viewpoint as the open space quantification assessment result corresponding to the three-dimensional space. The calculation of the open space volume index uses the three-dimensional observation point as the smallest calculation unit, without needing to use the entire building as the smallest calculation unit, which is beneficial for realizing the open space quantification assessment of specific spatial points. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart illustrating a method for quantitatively evaluating open space between three-dimensional buildings, as provided in an embodiment of this application.

[0041] Figure 2 This application provides a quantized map of open space corresponding to a three-dimensional space.

[0042] Figure 3 This is a schematic diagram illustrating the specific process of a method for quantitatively evaluating open space between three-dimensional buildings, as provided in an embodiment of this application.

[0043] Figure 4 This is a schematic diagram of the constituent modules of a three-dimensional open space quantitative assessment system between buildings provided in an embodiment of this application;

[0044] Figure 5 This is a block diagram illustrating the internal structure of a smart terminal provided in an embodiment of this application. Detailed Implementation

[0045] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0046] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0047] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0048] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0049] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to classification." Similarly, the phrases "if determined" or "if classified to [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once classified to [the described condition or event]," or "in response to classification to [the described condition or event]."

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0052] Currently, the quantification and assessment of three-dimensional urban space is becoming increasingly important. The value of open spaces in cities, such as parks, community vacant lots, pedestrian streets, and irregular spaces between buildings, urgently needs to be explored in depth. However, there is still a lack of effective quantitative methods to objectively judge and identify the spatial extent, structural composition, and spatiotemporal characteristics of these spaces.

[0053] Current methods for quantifying and evaluating three-dimensional urban space mainly use attributes related to three-dimensional building data for characterization, such as urban volume, fractal dimension, building coverage, floor area ratio, average number of floors per building, building density, and openness. However, these calculations based on building attribute data are limited by data quality, spatial analysis scale, and the physical meaning of indicators. The smallest calculation unit is often a building, a plot of land, a spatial grid, or an administrative division unit such as a street or community. It is difficult to achieve accurate quantification of any spatial point, and the interpretability of spatial heterogeneity is insufficient.

[0054] In some applications, skyline analysis and viewpoint analysis can be used to quantitatively study 3D space from a specific viewpoint. These methods mainly rely on two technical approaches: 2D slicing and 3D voxels. 2D slicing discretizes 3D space into multiple 2D planes and determines visibility by superimposing the visible pixels in each 2D space. This method essentially falls under the category of 2D viewpoint analysis and struggles to effectively convert 2D visible distance / area into true 3D length / visible volume. The 3D voxel method discretizes 3D space into a regular voxel grid, using the voxel center as the observation target for visibility assessment. It assumes that the center's visibility represents the entire voxel space's visibility, ultimately obtaining the skyline length / overall visible volume by accumulating the visible voxel length / volume. However, this method suffers from computational complexity that depends on the voxelization granularity and requires full-space voxel traversal. In urban-scale applications, there are numerous issues such as ineffective calculations. The computational time complexity for three dimensions increases exponentially.

[0055] Urban renewal scenarios for existing buildings often feature dense, fragmented spaces and complex existing structures, leading to low efficiency or insufficient accuracy in traditional three-dimensional open space calculations. Therefore, this application proposes a quantitative evaluation method for open spaces between buildings based on visual field analysis, which effectively quantifies spatial value from the perspective of visual perception.

[0056] Specifically, to solve at least one of the aforementioned technical problems, the solution of this application involves: obtaining the minimum bounding box corresponding to the three-dimensional building model in three-dimensional space; obtaining observation point control parameters; and generating three-dimensional observation viewpoints that do not overlap with the three-dimensional building model within the space defined by the minimum bounding box, based on the minimum bounding box and the observation point control parameters, wherein the observation point control parameters include the total number of observation points and the maximum viewpoint height; and for each of the aforementioned three-dimensional observation viewpoints, generating a corresponding pushbroom point set on the surface of the three-dimensional building model using a pushbroom method, removing the invisible points in the pushbroom point set, and obtaining a visible pushbroom result. A visual pushbroom set composed of points; the building field volume corresponding to each of the above three-dimensional observation viewpoints is calculated based on the visual pushbroom set corresponding to each of the above three-dimensional observation viewpoints; the theoretical field volume corresponding to each of the above three-dimensional observation viewpoints is obtained; based on the building field volume and the theoretical field volume, the field volume openness index corresponding to each of the above three-dimensional observation viewpoints is calculated and used as the quantitative evaluation result of the open space corresponding to the above three-dimensional space. Among them, the field volume openness index corresponding to a three-dimensional observation viewpoint is determined according to the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the above three-dimensional observation viewpoint.

[0057] Compared with existing technologies, the open space quantification assessment method between three-dimensional buildings provided in this application generates three-dimensional observation viewpoints for the three-dimensional space and calculates the open space volume index corresponding to each three-dimensional observation viewpoint as the open space quantification assessment result corresponding to the three-dimensional space. The calculation of the open space volume index uses the three-dimensional observation point as the smallest calculation unit, without needing to use the entire building as the smallest calculation unit, which is beneficial for realizing the open space quantification assessment of specific spatial points.

[0058] like Figure 1 As shown in the figure, this application provides a method for quantitatively evaluating open spaces between three-dimensional buildings. Specifically, the method includes the following steps:

[0059] Step S100: Obtain the minimum bounding box corresponding to the 3D building model in 3D space.

[0060] Step S200: Obtain observation point control parameters. Based on the minimum bounding box and the observation point control parameters, generate a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model within the space defined by the minimum bounding box. The observation point control parameters include the total number of observation points and the maximum viewpoint height.

[0061] Step S300: For each of the above three-dimensional observation viewpoints, generate a corresponding pushbroom point set on the surface of the above three-dimensional building model using the pushbroom method, remove the unseen points in the pushbroom point set, and obtain a visible pushbroom point set composed of visible pushbroom points.

[0062] Step S400: Calculate the building field volume corresponding to each of the three-dimensional observation viewpoints based on the visual pushbroom set corresponding to each of the three-dimensional observation viewpoints.

[0063] It should be noted that the open space quantification assessment method between three-dimensional buildings provided in this application embodiment can be divided into two parts. The first part includes the calculation of the visible volume of any point in the irregular space, as shown in steps S100 to S400 above. The second part mainly includes the establishment and processing of the open space visible volume quantification model, as shown in step S500 below.

[0064] In this embodiment of the application, the method for quantitatively evaluating the open space between three-dimensional buildings is further described in detail based on a specific application scenario. Specifically, when performing bounding box calculation, the three-dimensional city model is read, and the minimum bounding box of the three-dimensional scene is obtained. The minimum bounding box is determined by the maximum and minimum coordinates of the geometric model in the three-dimensional scene.

[0065] Furthermore, the observation point control parameters are obtained, which are used to control the generation and processing of the three-dimensional observation viewpoint.

[0066] Specifically, the aforementioned observation point control parameters also include the observation point translation distance;

[0067] The aforementioned observation point translation distance is used to define the vertical translation distance of the aforementioned three-dimensional observation viewpoint each time during the generation of the aforementioned push-broom point set.

[0068] Furthermore, the aforementioned observation point control parameters also include the farthest line-of-sight distance, the maximum directional angle, and the observation point translation distance;

[0069] The above process of removing unseen points from the pushbroom point set yields a visible pushbroom point set consisting of visible pushbroom points, including:

[0070] Rays are emitted from the above three-dimensional observation viewpoints to all push points in the corresponding push point set, and push points that cannot be reached by the rays are regarded as unviewable points.

[0071] Calculate the azimuth angle of the above-mentioned push-broom point relative to the above-mentioned three-dimensional observation viewpoint, and take the push-broom point whose azimuth angle exceeds the above-mentioned maximum direction angle as an unseen point.

[0072] Calculate the Euclidean distance between the above three-dimensional observation viewpoint and the above push-broom point, and designate the points whose Euclidean distance exceeds the above farthest line-of-sight distance as unviewable points;

[0073] Delete all unseen points from the above pushbroom point set to obtain a visible pushbroom point set consisting of visible pushbroom points.

[0074] In this embodiment, the corresponding observation point control parameters are obtained according to user requirements to achieve the above processing. The obtained observation point control parameters in this embodiment are shown in Table 1 below:

[0075] Table 1

[0076]

[0077] It should be noted that the default values ​​of the parameters shown in Table 1 are for illustrative purposes only and are not intended as specific limitations. Based on the above observation point control parameters, n three-dimensional observation viewpoints are randomly generated in three-dimensional space. The rule for randomly generating viewpoints is to generate 3D viewpoints that do not overlap with the 3D building model within the smallest bounding box, and each 3D viewpoint... Not exceeding the maximum viewpoint height h, used to simulate the observation point in a real 3D scene.

[0078] Furthermore, the above calculation of the building field volume corresponding to each of the three-dimensional observation viewpoints based on the visible pushbroom set corresponding to each of the three-dimensional observation viewpoints includes: for any three-dimensional observation viewpoint, connecting all the visible pushbroom points corresponding to the three-dimensional observation viewpoint to obtain a visible pushbroom surface constructed by a triangular mesh.

[0079] Connect each of the above-mentioned triangular meshes in the above-mentioned visual push-broom surface with the above-mentioned three-dimensional observation viewpoint to obtain the visual field pyramids corresponding to each of the above-mentioned triangular meshes;

[0080] The building's visual field volume corresponding to the three-dimensional observation viewpoint is determined based on the volume of each of the aforementioned visible field pyramids.

[0081] Specifically, for each 3D viewpoint, the corresponding set of pushbroom points is calculated. To ensure the accuracy of the view space modeling, a pushbroom method is used to generate uniformly distributed view space pushbroom points on the building surface. The specific process is as follows: a set of rays is emitted from the viewpoint, intersecting with the building surface to generate a series of pushbroom points; the vertical step size is set. The observation point is then shifted upwards or downwards sequentially for the next ray emission. This process is repeated until a complete pushbroom set is obtained. Step size The default setting is 0.1 meters (which can be set and adjusted according to actual needs), defining the distance the observation point is vertically moved each time.

[0082] For each 3D observation viewpoint, the generated pushbroom point set needs to be processed to remove unseen points. This process is achieved by performing the following three visibility checks on each pushbroom point in sequence: Ray casting detection: A ray is emitted from the observation point to the pushbroom point. If the ray is blocked and cannot reach the target point, the pushbroom point is removed. Viewing angle range detection: The azimuth angle of the pushbroom point relative to the observation point is calculated. If it exceeds the preset human eye field of view range... If the distance between the observation point and the push-broom point exceeds the set maximum visible distance d, then the push-broom point is removed. Finally, only push-broom points that simultaneously meet all three conditions are retained.

[0083] Furthermore, for each three-dimensional viewing point, the volume of the field of view formed by its intersection with the building surface is calculated. In this embodiment, the specific calculation process for a three-dimensional observation viewpoint is illustrated as an example. First, the retained visible sweep points are connected to construct a visible sweep surface (composed of a triangular mesh) on the building surface; then, each triangle in the mesh is connected to the observation point to form a corresponding visible field pyramid; then, the volume of each pyramid is calculated separately; finally, the volumes of all pyramids are summed to obtain the visible field volume of the observation point, as shown in the following formula (1):

[0084] (1);

[0085] in, This represents the field of view volume of the three-dimensional observation point, specifically characterizing the volume of the building that can be observed by the line of sight from this three-dimensional observation point. Indicates the first visible push scan surface The area of ​​the triangular grid, Indicates the 3D viewing viewpoint to the 1st The distance between the planes containing the triangular grids This indicates the number of triangular meshes in the visible push-broom surface.

[0086] Step S500: Obtain the theoretical field volume corresponding to each of the above three-dimensional observation viewpoints. Based on the building field volume and the theoretical field volume, calculate the field volume openness index corresponding to each of the above three-dimensional observation viewpoints and use it as the quantitative evaluation result of the open space corresponding to the above three-dimensional space. The field volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the above three-dimensional observation viewpoint.

[0087] In this embodiment of the application, a target ratio is defined. That is, the ratio of the building's visual field volume observed by the line of sight to the total visual field volume, as shown in the following formula (2):

[0088] (2);

[0089] The theoretical field of view volume refers to the maximum visible space that an observer (viewpoint) can see in three-dimensional space under ideal conditions without any obstruction. Essentially, it is a geometric volume (usually a view frustum or hemisphere). In this embodiment, the theoretical field of view volume is obtained by calculating the volume corresponding to the view frustum using the current three-dimensional observation viewpoint as the camera point. It is typically determined by the camera's position (spatial coordinates of the observation point), orientation (direction of the observation point's line of sight), and field of view angle (…). The calculation is accomplished using parameters such as near and far cutting planes, and existing algorithms can be used for the calculation, but no specific limitations are made here.

[0090] Based on the above target ratio, the Volume Openness Index (VOI) corresponding to the above three-dimensional observation viewpoint is further calculated, as shown in the following formula (3):

[0091] (3);

[0092] It should be noted that in this embodiment, the aforementioned preset constant value is 1, so that the calculated field volume openness index can more directly characterize the spatial openness corresponding to the point. Specifically, the field volume openness index is used to characterize the ratio of the visible building volume to the visible sky volume corresponding to the observation point. The field volume openness index ranges from 0 to 1. The smaller the size, the larger the proportion of the building's visual field, indicating a higher degree of influence from the building on the space and a more cramped feeling; conversely, the larger the size, the more confined the space. The larger the value, the more open the space.

[0093] In this embodiment of the application, the field volume openness index corresponding to each of the above-mentioned three-dimensional observation viewpoints is used as the quantitative evaluation result of the open space corresponding to the above-mentioned three-dimensional space. This can intuitively characterize the degree of openness corresponding to each point in the three-dimensional space and provide a reference for users.

[0094] Furthermore, after calculating the field-of-view volume openness index corresponding to each of the three-dimensional observation viewpoints and using it as the quantitative evaluation result of the open space corresponding to the three-dimensional space, the method further includes:

[0095] The above-mentioned view volume openness index is interpolated based on a preset interpolation method to obtain the view volume openness index corresponding to multiple points to be solved in the above three-dimensional space.

[0096] The above quantitative assessment results of open space are updated based on the openness index of the field volume corresponding to the points to be solved.

[0097] Among them, the aforementioned preset interpolation method includes radial basis interpolation.

[0098] Since the field-of-view volume openness index only defines the degree of openness or crampedness at a certain spatial point and lacks a quantitative evaluation of continuous three-dimensional space, this embodiment further employs a radial basis interpolation method to achieve a data-driven openness index. This method interpolates the openness index of 3D coordinate points (i.e., 3D viewpoints) of data. The radial basis function chosen is the thin-plate spline function, which corrects outliers based on higher-order spline functions, effectively handling 3D spatial data with nonlinearity and noise. Compared to the classic inverse distance weighting method and 3D nearest neighbor interpolation, it produces smoother surfaces to reduce jagged edges. Compared to Kriging interpolation, it is more suitable for handling complex spatial distribution problems and performs better on sparse data.

[0099] Specifically, let's start with... Calculate the field of view volume openness index for each three-dimensional coordinate point (i.e., the three-dimensional viewing point): based on the parameters input by the user. Randomly generated These three-dimensional coordinate points are calculated using formula (3). The field-of-view volume openness index of a point. Record this. The points are the set of sampling points. ,in For point Position coordinates in three-dimensional space To obtain the field of view volume openness index corresponding to this point.

[0100] Furthermore, the view volume openness index of the point to be solved is interpolated. To calculate the view volume openness index of any point to be solved, the heterogeneity of the three-dimensional space must be considered. The point to be solved is any point in the three-dimensional space whose view volume openness index needs to be determined. It should be noted that in this embodiment, the point to be solved does not exceed the range defined by the minimum bounding box in the three-dimensional space. That is, in this application, the view volume openness index corresponding to points outside the minimum bounding box in the three-dimensional space is not calculated during interpolation to reduce computational load and improve data processing efficiency.

[0101] Specifically, a local neighborhood sphere is constructed with the point to be solved as the center and its farthest line-of-sight distance *d* as the radius. Line-of-sight detection is performed on all sampling points within this neighborhood, and only visible sampling points are retained for calculation. Subsequently, the openness index of the view volume of these visible sampling points within the neighborhood is used. A radial basis function model is constructed, and the view volume openness index of the point to be determined is solved by linear weighting, as shown in the following formulas (4) and (5):

[0102] (4);

[0103] (5);

[0104] in, The simulated value represents the openness index of the field of view of the point to be solved. It is the first The weights of each sampling point are functions of the distance in three-dimensional space. It is the first The Euclidean distance between each sampling point and the point to be solved; This represents the natural logarithm to the base e. k = 2, 4, 6, ..., determined based on the convergence value of the simulation function, with a default value of 2; b is a constant, and its specific value can be set and adjusted according to actual needs. The three-dimensional spatial field data generated through interpolation can obtain specific quantitative evaluation values ​​for any spatial location point, enabling the quantification of irregular spaces.

[0105] Preferably, the above method further includes: generating an open space quantization map corresponding to the above three-dimensional space based on the open space quantization evaluation result corresponding to the above three-dimensional space, wherein the open space quantization map is used to visualize and output the field of view volume openness index corresponding to each point in the above three-dimensional space.

[0106] Figure 2 This application provides a quantization map of open space corresponding to a three-dimensional space, such as... Figure 2 As shown, users can directly determine the openness index of the view volume corresponding to each point based on the open space quantization map. It should be noted that... Figure 2 This explanation uses a two-dimensional image as an example; however, three-dimensional images can also be constructed in practical applications, and this is not a specific limitation. It should be further noted that... Figure 2 In this context, different colors represent different field of view volume openness index values. In practical applications, the specific numbers corresponding to the field of view volume openness index can also be directly marked, without any specific limitations here.

[0107] Figure 3 This is a schematic diagram illustrating the specific process of a method for quantitatively evaluating open space between three-dimensional buildings, as provided in an embodiment of this application. Figure 3 As shown in this embodiment, after importing the 3D building model, a 3D observation viewpoint is randomly generated, then a pushbroom point set is generated, a visible pushbroom point set is selected and constructed, and then the building's visual field volume corresponding to the 3D observation viewpoint is calculated, and the visual field volume openness index is further calculated. Based on this, interpolation is used to achieve a quantitative evaluation of the 3D space, and the results are visualized to improve the user experience.

[0108] Specifically, when calculating the visible volume, the bounding box of the 3D scene is calculated, and a specified number of n coordinate points are randomly generated in space. The visible volume of each generated coordinate point is calculated. The open space index is calculated for each of the n points. Finally, a 3D local radial spatial interpolation algorithm is used to quantitatively evaluate irregular spaces. The open space quantitative evaluation method between 3D buildings provided in this application can be applied to existing space renewal scenarios, providing a calculation model and method for the value evaluation of existing spaces.

[0109] It should be noted that traditional 3D view domain calculation methods based on voxelization and ray detection are approximate solutions. Their accuracy is significantly affected by voxel granularity, and the computational complexity increases exponentially, resulting in low computational efficiency and complex principles. In real 3D open spaces between buildings, the human eye's visible field of view is constrained by both the building entity and the sky hemisphere. The former constitutes a visual occlusion boundary, while the latter limits the range of line-of-sight propagation. Therefore, this application's embodiment, by coupling the 3D building model with the hemispherical view domain constraint, semantically divides the view domain volume into visible building volume and visible sky volume, and calculates the building occlusion volume and the visible sky volume. By proposing an equidistant sweeping method on the building surface, rays are emitted onto the building surface and the intersection points are extracted as potential visible points, ensuring that the resulting point set strictly fits the building surface, thereby generating a high-precision fitted visible surface polyhedron, and using the openness index to quantify the urban 3D building space. The solution of this application's embodiment can not only effectively reduce data storage, but also significantly improve the calculation accuracy and efficiency of visible volume, while providing a tool for accurately determining inefficient 3D spaces and scientifically managing space in urban renewal.

[0110] In this embodiment of the application, a custom total number of viewpoints parameter is also designed. Users can control the accuracy of the results according to the custom parameter, and the calculation process is a vector calculation, which has high computational efficiency.

[0111] Thus, in the method for quantitatively evaluating open space between three-dimensional buildings provided in this application embodiment, three-dimensional observation viewpoints are generated for the three-dimensional space, and the openness index of the field of view volume corresponding to each three-dimensional observation viewpoint is calculated as the quantitative evaluation result of the open space corresponding to the above-mentioned three-dimensional space. The calculation of the openness index of the field of view volume uses the three-dimensional observation point as the smallest calculation unit, without needing to use the entire building as the smallest calculation unit, which is beneficial for realizing the quantitative evaluation of open space at specific spatial points.

[0112] like Figure 4 As shown in the figure, corresponding to the above-mentioned method for quantitatively evaluating open spaces between three-dimensional buildings, this application embodiment also provides a system for quantitatively evaluating open spaces between three-dimensional buildings, the system comprising:

[0113] The bounding box acquisition module 410 is used to acquire the minimum bounding box corresponding to the three-dimensional building model in three-dimensional space.

[0114] The observation point generation module 420 is used to obtain observation point control parameters and generate a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model within the space defined by the minimum bounding box and the observation point control parameters. The observation point control parameters include the total number of observation points and the maximum viewpoint height.

[0115] The pushbroom point generation module 430 is used to generate a corresponding pushbroom point set on the surface of the three-dimensional building model for each of the above three-dimensional observation viewpoints by using the pushbroom method, remove the invisible points in the pushbroom point set, and obtain a visible pushbroom point set composed of visible pushbroom points.

[0116] The first calculation module 440 is used to calculate the building visual volume corresponding to each of the three-dimensional observation viewpoints based on the visual pushbroom set corresponding to each of the three-dimensional observation viewpoints.

[0117] The second calculation module 450 is used to obtain the theoretical field volume corresponding to each of the above-mentioned three-dimensional observation viewpoints, and calculate the field volume openness index corresponding to each of the above-mentioned three-dimensional observation viewpoints based on the building field volume and the theoretical field volume, and use it as the quantitative evaluation result of the open space corresponding to the above-mentioned three-dimensional space. The field volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the above-mentioned three-dimensional observation viewpoint.

[0118] Thus, three-dimensional observation viewpoints are generated for the three-dimensional space, and the openness index of the field of view volume corresponding to each three-dimensional observation viewpoint is calculated as the quantitative evaluation result of the open space corresponding to the above three-dimensional space. The calculation of the openness index of the field of view volume uses the three-dimensional observation point as the smallest calculation unit, without having to use the entire building as the smallest calculation unit, which is conducive to realizing the quantitative evaluation of the open space of specific spatial points.

[0119] It should be noted that the specific structure and implementation of the above-mentioned three-dimensional open space quantitative assessment system between buildings and its various modules or units can be referred to the corresponding descriptions in the above method embodiments, and will not be repeated here.

[0120] It should be noted that the division of the modules in the above-mentioned three-dimensional open space quantitative assessment system between buildings is not unique and is not intended as a specific limitation.

[0121] Based on the above embodiments, this application also provides a smart terminal, the principle block diagram of which can be as follows: Figure 5As shown. The aforementioned intelligent terminal includes a processor, memory, network interface, and display screen connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements the steps of any of the above-described methods for quantitatively evaluating the open space between three-dimensional buildings. The display screen of the intelligent terminal can be a liquid crystal display (LCD) or an e-ink display.

[0122] Those skilled in the art will understand that Figure 5 The block diagram shown is only a partial structural diagram related to the solution of this application and does not constitute a limitation on the smart terminal on which the solution of this application is applied. The specific smart terminal may include more or fewer components than shown in the figure, or combine some components, or have different component arrangements.

[0123] In one embodiment, a smart terminal is provided, the smart terminal including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of any of the three-dimensional building space quantitative evaluation methods provided in the embodiments of this application.

[0124] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of any of the three-dimensional building open space quantitative evaluation methods provided in this application.

[0125] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0126] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0127] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0128] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0129] In the embodiments provided in this application, it should be understood that the disclosed systems / terminal devices and methods can be implemented in other ways. For example, the system / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units described above is merely a logical functional division, and in actual implementation, it can be divided in other ways. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0130] If the integrated modules / units described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, and software distribution media, etc. It should be noted that the content included in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0131] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions are not in essence a departure from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for quantitatively evaluating open spaces between three-dimensional buildings, characterized in that, The method includes: Obtain the minimum bounding box corresponding to the 3D building model in 3D space; Obtain observation point control parameters, and generate a three-dimensional observation viewpoint that does not overlap with the three-dimensional building model within the space defined by the minimum bounding box based on the minimum bounding box and the observation point control parameters. The observation point control parameters include the total number of observation points and the maximum viewpoint height. For each of the three-dimensional observation viewpoints, a corresponding set of pushbroom points is generated on the surface of the three-dimensional building model using the pushbroom method. The unseen points in the set of pushbroom points are removed to obtain a set of visible pushbroom points composed of visible pushbroom points. The building visual volume corresponding to each of the three-dimensional observation viewpoints is calculated based on the visual pushbroom set corresponding to each of the three-dimensional observation viewpoints. The theoretical field of view volume corresponding to each of the three-dimensional observation viewpoints is obtained. Based on the building field of view volume and the theoretical field of view volume, the field of view volume openness index corresponding to each of the three-dimensional observation viewpoints is calculated and used as the quantitative evaluation result of the open space corresponding to the three-dimensional space. The field of view volume openness index corresponding to a three-dimensional observation viewpoint is determined according to the difference between a preset constant value and a target ratio. The target ratio is the ratio of the building field of view volume to the theoretical field of view volume corresponding to the three-dimensional observation viewpoint. The observation point control parameters also include the farthest line-of-sight distance, the maximum directional angle, and the observation point translation distance; The observation point translation distance is used to limit the vertical translation distance of the three-dimensional observation viewpoint each time during the generation of the push-broom point set; The step of removing unseen points from the pushbroom point set to obtain a visible pushbroom point set consisting of visible pushbroom points includes: A ray is emitted from the three-dimensional observation viewpoint to all push points in the corresponding push point set, and push points that the ray cannot reach are regarded as unviewable points. Calculate the azimuth angle of the push-broom point relative to the three-dimensional observation viewpoint, and designate push-broom points whose azimuth angle exceeds the maximum direction angle as unvisible points; Calculate the Euclidean distance between the three-dimensional observation viewpoint and the push-broom point, and designate points whose Euclidean distance exceeds the farthest line-of-sight distance as unviewable points; Delete all unseen points in the pushbroom point set to obtain a visible pushbroom point set consisting of visible pushbroom points.

2. The method for quantitatively evaluating open spaces between three-dimensional buildings according to claim 1, characterized in that, The step of calculating the building field volume corresponding to each of the three-dimensional observation viewpoints based on the visible pushbroom set corresponding to each of the three-dimensional observation viewpoints includes: for any three-dimensional observation viewpoint, connecting all the visible pushbroom points corresponding to the three-dimensional observation viewpoint to obtain a visible pushbroom surface constructed by a triangular mesh; Connect each of the triangular meshes in the visible push-broom surface to the three-dimensional observation viewpoint to obtain the visible field pyramids corresponding to each of the triangular meshes; The building's visual field volume corresponding to the three-dimensional observation viewpoint is determined based on the volume of each of the aforementioned visual field pyramids.

3. The method for quantitatively evaluating open spaces between three-dimensional buildings according to claim 1, characterized in that, After calculating and obtaining the field-of-view volume openness index corresponding to each of the three-dimensional observation viewpoints and using it as the quantitative evaluation result of the open space corresponding to the three-dimensional space, the method further includes: The view volume openness index is interpolated based on a preset interpolation method to obtain the view volume openness index corresponding to multiple points to be solved in the three-dimensional space. The quantitative evaluation result of the open space is updated based on the openness index of the field volume corresponding to the point to be solved.

4. The method for quantitatively evaluating open spaces between three-dimensional buildings according to claim 3, characterized in that, The preset interpolation method includes radial basis interpolation.

5. The method for quantitatively evaluating open spaces between three-dimensional buildings according to any one of claims 1 to 4, characterized in that, The method further includes: Based on the quantitative evaluation results of the open space corresponding to the three-dimensional space, a quantitative map of the open space corresponding to the three-dimensional space is generated. The quantitative map of the open space is used to visualize and output the openness index of the view volume corresponding to each point in the three-dimensional space.

6. A three-dimensional quantitative assessment system for open space between buildings, characterized in that, The system includes: The bounding box acquisition module is used to obtain the minimum bounding box corresponding to the 3D building model in 3D space; The observation point generation module is used to obtain observation point control parameters and generate three-dimensional observation viewpoints that do not overlap with the three-dimensional building model within the space defined by the minimum bounding box, based on the minimum bounding box and the observation point control parameters. The observation point control parameters include the total number of observation points and the maximum viewpoint height. The pushbroom point generation module is used to generate a corresponding pushbroom point set on the surface of the three-dimensional building model for each of the three-dimensional observation viewpoints by using the pushbroom method, and to remove the invisible points in the pushbroom point set to obtain a visible pushbroom point set composed of visible pushbroom points. The first calculation module is used to calculate the building visual volume corresponding to each of the three-dimensional observation viewpoints based on the visual pushbroom set corresponding to each of the three-dimensional observation viewpoints. The second calculation module is used to obtain the theoretical field volume corresponding to each of the three-dimensional observation viewpoints, and calculate the field volume openness index corresponding to each of the three-dimensional observation viewpoints based on the building field volume and the theoretical field volume, and use it as the quantitative evaluation result of the open space corresponding to the three-dimensional space. The field volume openness index corresponding to a three-dimensional observation viewpoint is determined based on the difference between a preset constant value and a target ratio, wherein the target ratio is the ratio of the building field volume to the theoretical field volume corresponding to the three-dimensional observation viewpoint. The observation point control parameters also include the farthest line-of-sight distance, the maximum directional angle, and the observation point translation distance; The observation point translation distance is used to limit the vertical translation distance of the three-dimensional observation viewpoint each time during the generation of the push-broom point set; The pushbroom point generation module is specifically used to: emit rays from the three-dimensional observation viewpoint to all pushbroom points in the corresponding pushbroom point set, and treat pushbroom points that the rays cannot reach as unviewable points. Calculate the azimuth angle of the push-broom point relative to the three-dimensional observation viewpoint, and designate push-broom points whose azimuth angle exceeds the maximum direction angle as unvisible points; Calculate the Euclidean distance between the three-dimensional observation viewpoint and the push-broom point, and designate points whose Euclidean distance exceeds the farthest line-of-sight distance as unviewable points; Delete all unseen points in the pushbroom point set to obtain a visible pushbroom point set consisting of visible pushbroom points.

7. A smart terminal, characterized in that, The smart terminal includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of the quantitative evaluation method for open space between three-dimensional buildings as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the quantitative evaluation method for open space between three-dimensional buildings as described in any one of claims 1 to 5.

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