Method for rapidly estimating shielding effect of dynamic evolution spherical light source under single building

Abstract

The invention discloses a method for rapidly estimating the shielding effect of a dynamic evolution spherical surface light source under a single building, and solves the problems that the shielding effect calculation efficiency of the existing dynamic evolution spherical surface light source under the single building is low, the rapid evaluation requirement cannot be met, and when building parameters or light sources in a scene change, recalculation is needed, and the evaluation efficiency is poor. And the real-time performance and the flexibility are seriously insufficient. According to the method, the spherical light source with the radius and height dynamically changing is considered, the shielding area of the single building can be rapidly estimated, the calculation precision is within an acceptable range, and the calculation time is greatly shortened.

Description

Technical Field

[0001] This invention relates to the field of optical numerical simulation methods, specifically to a fast estimation method for the shading effect of a dynamically evolving spherical light source under a single building. Background Technology

[0002] Target occlusion is a crucial factor influencing the spatial distribution characteristics of light transmission. Compared to unobstructed light transmission, occlusion significantly alters spatial optical parameters, severely impacting key characteristics such as the irradiated area and light intensity. Since urban scenes are filled with numerous buildings, they significantly obstruct light transmission, affecting the calculation of the obstructed area. Therefore, obtaining the obstructed area of ​​buildings is a prerequisite for accurately assessing light transmission and its irradiation effects.

[0003] For dynamically evolving light sources, their size, position, and intensity exhibit strong time-varying characteristics, making it impossible to calculate their occlusion effect using static point light source methods. Therefore, calculating the occlusion area of ​​buildings requires numerical methods such as Monte Carlo ray tracing and finite element analysis. Although these methods offer high accuracy, their computational efficiency is low, failing to meet the needs of rapid evaluation. In particular, when building parameters or light sources change within the scene, recalculation is required, resulting in severe deficiencies in real-time performance and flexibility. Summary of the Invention

[0004] The purpose of this invention is to address the problems of low computational efficiency of existing dynamic evolution spherical light sources for occlusion effects under single buildings, which cannot meet the needs of rapid evaluation, and the need for recalculation when building parameters or light sources change in the scene, resulting in serious deficiencies in real-time performance and flexibility. Therefore, this invention provides a fast estimation method for occlusion effects of dynamic evolution spherical light sources under single buildings.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A fast estimation method for the shading effect of a dynamically evolving spherical light source under a single building, characterized by the following steps:

[0007] Step 1: Establish a local rectangular coordinate system based on the scene settings;

[0008] Step 2: Determine the location, length l, width w, and height h of the individual building, and set the coordinates of the center point of the bottom surface of the individual building in the local rectangular coordinate system as (x0, y0, 0);

[0009] Step 3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. x y-axis component S y ;

[0010] Step 4: Convert the x-axis component Sx Component S with respect to the y-axis y Adding them together, we get the shading area S formed by the dynamic evolution spherical light source illuminating the single building on the horizontal plane.

[0011] Further, in step 1, the method for establishing the local rectangular coordinate system is as follows: the coordinate system constructed with the projection of the center point of the spherical light source on the horizontal plane as the origin, the due east direction as the positive x-axis, the due north direction as the positive y-axis, and the plane perpendicular to the x-axis and y-axis upward as the positive z-axis is the local rectangular coordinate system, wherein the coordinate unit is meters.

[0012] Furthermore, in step 2, the length and width of the individual building are parallel to the x-axis and y-axis of the local rectangular coordinate system, respectively, and the projection of the geometric center of the individual building onto the horizontal plane is taken as the center of the bottom surface of the individual building in the local rectangular coordinate system.

[0013] Furthermore, step 3 specifically involves:

[0014] Step 3.1: The radius and height of the dynamically evolving spherical light source gradually increase over time, and the light emission time of the spherical light source is t seconds;

[0015] Step 3.2: Calculate the y-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. y The calculation formula is:

[0016]

[0017] Where z is the calculated height of the center point of the spherical light source, and r z It is the calculated radius of the spherical light source;

[0018] Step 3.3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. x The calculation formula is:

[0019]

[0020] Furthermore, in step 3, the area of ​​the shading formed by the dynamic evolution spherical light source illuminating the single building on the horizontal plane within the emission time t is the area of ​​the full shadow zone, excluding the bottom surface of the building.

[0021] Furthermore, in step 3, the relationship between the calculated height z of the center point of the spherical light source and the initial position z0 of the center point of the spherical light source is as follows:

[0022] z = a * z0 + b;

[0023] Where a and b are both fitting coefficients.

[0024] In step 4, the formula for calculating the shading area S is:

[0025] S = S x +S y .

[0026] The beneficial effects of this invention are:

[0027] This invention provides a method for rapidly estimating the shading effect of a dynamically evolving spherical light source under a single building. It considers the spherical light source with dynamically changing radius and height, and can quickly estimate the shading area of ​​a single building with acceptable calculation accuracy and significantly reduced calculation time. Attached Figure Description

[0028] Figure 1 A flowchart illustrating an embodiment of the method for rapidly estimating the shading effect of a dynamically evolving spherical light source under a single building, provided by the present invention;

[0029] Figure 2 In an embodiment of the method for fast estimation of occlusion effect of a dynamically evolving spherical light source under a single building provided by the present invention, a schematic diagram of the dynamically evolving spherical light source and the single building scene is shown.

[0030] Figure 3 In an embodiment of the method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building provided by the present invention, a schematic diagram of the shading area of ​​the dynamically evolving spherical light source under a single building and its x-axis area components and y-axis area components is shown.

[0031] Figure 4 This invention provides a method for rapidly estimating the shading effect of a dynamically evolving spherical light source under a single building, illustrating the shading area of ​​the single building located in the positive y-axis direction.

[0032] Figure 5 In an embodiment of the method for rapidly estimating the occlusion effect of a dynamically evolving spherical light source under a single building provided by the present invention, the occlusion area results of multiple scenarios with different initial positions of the spherical light source and the single building located at different distances along the positive y-axis are shown in the numerical simulation calculation.

[0033] In the figure, (a) and (b) represent the occlusion area display results when the single building is 500m and 1500m away from the origin of the coordinate system, respectively, with the initial position of the point light source being 1000m away. (c) and (d) represent the occlusion area display results when the single building is 500m and 1500m away from the origin of the coordinate system, respectively, with the initial position of the point light source being 2000m away. (e) and (f) represent the occlusion area display results when the single building is 500m and 1500m away from the origin of the coordinate system, respectively, with the initial position of the point light source being 3000m away.

[0034] Figure 6In an embodiment of the method for rapidly estimating the occlusion effect of a dynamically evolving spherical light source under a single building provided by the present invention, the statistical curves of the occlusion area are calculated by numerical simulation of multiple scenarios with different initial positions of the spherical light source and different distances of the single building on the positive y-axis.

[0035] Figure 7 In an embodiment of the fast estimation method for the shading effect of a dynamically evolving spherical light source under a single building provided by the present invention, the fitting radius r of the spherical light source at different initial positions is... z Fit the height z-curve;

[0036] Figure 8 In an embodiment of the method for rapidly estimating the shading effect of a dynamically evolving spherical light source under a single building provided by the present invention, a relative error diagram is shown between the numerical simulation calculation results of the shading area and the formula calculation results for multiple scenarios with different initial positions of the spherical light source and the center point of the building's bottom surface located at (800m, 800m). Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] This embodiment provides a fast estimation method for the shading effect of a dynamically evolving spherical light source under a single building, such as... Figure 1 As shown, it includes the following steps:

[0039] Step 1: Based on the scene settings, establish a local rectangular coordinate system. The method is as follows: take the projection of the center point of the spherical light source on the horizontal plane as the origin, the east direction as the positive x-axis, the north direction as the positive y-axis, and the plane perpendicular to the x-axis and y-axis upward as the positive z-axis. The coordinate unit is meters.

[0040] Step 2: Determine the location, length l, width w, and height h of the individual building. Set the coordinates of the center point of the building's bottom surface in the local rectangular coordinate system as (x0, y0, 0), such as... Figure 2 As shown.

[0041] In this system, the length and width of a single building are parallel to the x-axis and y-axis of the local rectangular coordinate system, respectively, and the projection of the geometric center of the single building onto the horizontal plane is taken as the center of the bottom surface of the single building in the local rectangular coordinate system.

[0042] Step 3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. xy-axis component S y Specifically:

[0043] Step 3.1: The radius and height of the dynamically evolving spherical light source gradually increase over time, and the light emission time of the spherical light source is t seconds;

[0044] Step 3.2: Calculate the y-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. y The calculation formula is:

[0045]

[0046] Where z is the calculated height of the center point of the spherical light source, and r z It is the calculated radius of the spherical light source.

[0047] The calculated height z of the center point of the spherical light source and the calculated radius r of the spherical light source z The specific fitting method is as follows:

[0048] Assuming the individual building is located on the positive y-axis, such as Figure 4 As shown, with a building length of l meters, a width of w meters, and a building height of h meters, establish at least two sets of individual building scenes with different distances between the center point of the bottom surface of the individual building and the origin of the local rectangular coordinate system.

[0049] Choose the energy E of the spherical light source, the formula for the radius increasing with time, and the formula for the height increasing with time, and select at least two different initial positions z0 of the center point of the spherical light source.

[0050] Numerical simulations were performed on all individual building scenes at the initial position z0 of the center point of each spherical light source, and the area S of the fully occluded zone in the calculation results was statistically analyzed. y .

[0051] For at least two sets of individual building scene calculation results for the initial position z0 of the center point of each spherical light source, the area S of the total occlusion area is calculated. y Substituting the building length (l meters), width (w meters), and height (h meters) into the formula for calculating the y-axis component of the shading area formed by a dynamic evolution spherical light source illuminating a single building on the horizontal plane, the fitting radius R is obtained. z Fitting height Z. Fitting radius R of the spherical light source. z It is related to the energy of the light source and is a fixed value.

[0052] The fitting radius R corresponding to the initial position z0 of the center point of at least two different spherical light sources z By averaging, the corresponding computational radius r of the spherical light source is obtained. zLinear fitting is performed on the initial position z0 of the center point of at least two different spherical light sources and the corresponding fitting height Z to obtain the corresponding calculated height z of the spherical light source z = a*z0 + b, where a and b are both fitting coefficients.

[0053] The relationship between the calculated height z of the center point of the spherical light source and the initial position z0 of the center point of the spherical light source is as follows:

[0054] z = a * z0 + b;

[0055] Where a and b are both fitting coefficients.

[0056] Step 3.3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. x The calculation formula is:

[0057]

[0058] In this context, the area of ​​the shading formed by the dynamically evolving spherical light source on the horizontal plane of a single building within the emission time t is the area of ​​the total shadow zone, excluding the building's base surface. For example... Figure 3 As shown.

[0059] Step 4: Convert the x-axis component S x Component S with respect to the y-axis y Adding these together, we obtain the shading area S formed by the dynamic evolution spherical light source illuminating a single building on the horizontal plane. The formula for calculating the shading area S is:

[0060] S = S x +S y .

[0061] The following verification was performed on the fast estimation method for the shading effect of a dynamically evolving spherical light source under a single building provided in this embodiment:

[0062] The initial position of the spherical light source varies from 500m to 5000m. The radius and height of the light source are positively correlated with time. The building is 80m long, 40m wide, and 99m high. Multiple sets of numerical simulations were conducted for different initial positions of the spherical light source, with the building located at distances of 500m, 1000m, 1500m, 2000m, and 2500m from the origin on the positive y-axis. Figure 5In the diagram, (a) and (b) represent the occlusion area display results when the distance of a single building from the coordinate origin is 500m and 1500m, respectively, with the initial position of the point light source being 1000m and the occlusion area displayed. (c) and (d) represent the occlusion area display results when the distance of a single building from the coordinate origin is 500m and 1500m, respectively, with the initial position of the point light source being 2000m and the occlusion area displayed. (e) and (f) represent the occlusion area display results when the distance of a single building from the coordinate origin is 500m and 1500m, respectively, with the initial position of the point light source being 3000m and the occlusion area displayed. When the initial position of the spherical light source varies from 500m to 5000m, the area of ​​the completely occluded area in the statistical calculation results is shown below. Figure 6 As shown. Then, calculate the y-axis component based on the formula for calculating the y-axis component of the shading area formed by the dynamic evolution spherical light source illuminating a single building on the horizontal plane.

[0063] The fitting radius r of the spherical light source at different initial positions was obtained by fitting. z With the fitted height z, such as Figure 7 As shown, the fitting radius r corresponding to the initial position z0 of the center point of different spherical light sources is then determined. z By averaging, the corresponding computational radius r of the spherical light source is obtained. z =254.03m; Linear fitting is performed on the initial position z0 of the center point of different spherical light sources and the corresponding fitting height z to obtain the corresponding calculated height z of the spherical light source z = 1.008*z0 + 264.3m.

[0064] This yields the complete formula for calculating the shading area of ​​a single building illuminated by a dynamically evolving spherical light source on a horizontal plane:

[0065] S = S x +S y ;

[0066]

[0067] r z =254.03m;

[0068] z = 1.008 * z0 + 264.3m;

[0069] Next, for a scenario where the center point of the building's base is (800m, 800m), numerical simulations were conducted to determine the initial positions of spherical light sources at elevations of 1000m, 1500m, 2000m, 2500m, 3000m, 3500m, 4000m, 4500m, and 5000m. The area of ​​the fully occluded region in the calculation results and the occlusion area calculated using the formula were statistically analyzed. The relative errors between the two are as follows: Figure 8 As shown.

[0070] The calculation error of the method for rapidly estimating the shading area of ​​a single building under a dynamically evolving spherical light source provided by this invention is within 10%. Compared with the calculation time of numerical simulation methods, the calculation time of directly using the formula is negligible.

[0071] The above description is merely a specific embodiment of the present invention and a comparison of the effects of the specific embodiments with relevant comparative examples. However, the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for rapidly estimating the shading effect of a dynamically evolving spherical light source under a single building, characterized in that, Includes the following steps: Step 1: Establish a local rectangular coordinate system based on the scene settings; Step 2: Determine the location, length l, width w, and height h of the individual building, and set the coordinates of the center point of the bottom surface of the individual building in the local rectangular coordinate system as (x0, y0, 0); Step 3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. x y-axis component S y ; Step 4: Convert the x-axis component S x Component S with respect to the y-axis y Adding them together, we get the shading area S formed by the dynamic evolution spherical light source illuminating the single building on the horizontal plane.

2. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building according to claim 1, characterized in that: In step 1, the method for establishing the local rectangular coordinate system is as follows: the coordinate system constructed with the projection of the center point of the spherical light source on the horizontal plane as the origin, the east direction as the positive x-axis, the north direction as the positive y-axis, and the plane perpendicular to the x-axis and the y-axis upward as the positive z-axis is the local rectangular coordinate system, wherein the coordinate unit is meters.

3. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building according to claim 1, characterized in that: In step 2, the length and width of the individual building are parallel to the x-axis and y-axis of the local rectangular coordinate system, respectively, and the projection of the geometric center of the individual building onto the horizontal plane is taken as the center of the bottom surface of the individual building in the local rectangular coordinate system.

4. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building according to claim 3, characterized in that: Step 3 specifically involves: Step 3.1: The radius and height of the dynamically evolving spherical light source gradually increase over time, and the light emission time of the spherical light source is t seconds; Step 3.2: Calculate the y-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. y The calculation formula is: Where z is the calculated height of the center point of the spherical light source, and r z It is the calculated radius of the spherical light source; Step 3.3: Calculate the x-axis component S of the shading area formed by the dynamically evolving spherical light source illuminating a single building on the horizontal plane. x The calculation formula is:

5. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building, as described in claim 1 or 4, is characterized in that: In step 3, the area of ​​the shading formed by the dynamic evolution spherical light source illuminating the single building on the horizontal plane within the emission time t is the area of ​​the full shadow zone, excluding the bottom surface of the building.

6. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building according to claim 4, characterized in that: In step 3, the relationship between the calculated height z of the center point of the spherical light source and the initial position z0 of the center point of the spherical light source is as follows: z = a * z0 + b; Where a and b are both fitting coefficients.

7. The method for fast estimation of the shading effect of a dynamically evolving spherical light source under a single building according to claim 1, characterized in that: In step 4, the formula for calculating the shading area S is: S=S x +S y 。

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