A BIM-based field-of-view occlusion area rapid identification method and device

Abstract

The present application relates to the technical field of video monitoring, and particularly relates to a field-of-view occlusion area rapid identification method and device based on BIM. The present application arranges field-of-view models of each camera in a BIM project model of a to-be-identified monitoring area, and sequentially obtains an occlusion object set in the field-of-view model of each camera; then, a center contour of each occlusion object and a shadow boundary line on a bottom plane of the field-of-view model are drawn along a normal direction of a corresponding field-of-view model normal line, a field-of-view occlusion area space model of each occlusion object is fused and created, and a video simulation overlay simulation of the to-be-identified monitoring area is realized through connection processing. The scheme of the present application basically guarantees the authenticity and accuracy of the overlay simulation result, greatly improves the work efficiency of a designer, and overcomes the problems of a complicated field-of-view occlusion area calculation and design process, a large work volume, and difficulty in truly presenting a monitoring area overlay situation in the prior art.

Description

Technical Field

[0001] This invention relates to the field of video surveillance technology, and in particular to a method and device for rapid identification of field-of-view occlusion areas based on BIM. Background Technology

[0002] Limited by existing technological bottlenecks, traditional designs are based on planar layout drawings and rely on manual estimation of the occlusion impact of other objects using the camera's field of view buffer. This approach is cumbersome, involves a massive workload, and struggles to calculate the occlusion impact of other objects within the buffer zone, leading to significant deviations in calculation results. This results in an inability to accurately represent the coverage of the monitored area, causing a series of pressing problems such as unreasonable layout schemes, a surge in design changes, and high engineering implementation costs.

[0003] Therefore, a simpler and faster method and device for rapid identification of occluded areas of the field of view are needed. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of cumbersome calculation and design process for field-of-view occlusion areas, large workload, and difficulty in accurately presenting the coverage of the monitoring area in the existing technology, and to provide a BIM-based method and device for rapid identification of field-of-view occlusion areas.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A method for rapid identification of field-of-view occlusion regions based on BIM includes the following steps:

[0007] S1: In the BIM project model of the area to be identified and monitored, set up the field of view model of each camera;

[0008] S2: Select the field of view models of each camera in sequence, traverse the association relationship between the current field of view model and other objects in the project model, and generate a set of occluders associated with the current field of view model;

[0009] S3: Along the direction perpendicular to the normal of the current field of view model, extract the spatial cuboid center outline of each occluder in the set of occluders, and draw the shadow boundary line of the center outline located on the bottom plane of the field of view model;

[0010] S4: Based on the central contour and shadow boundary line of each occluder, establish a spatial model of the occlusion region of each occluder in the current field of view model;

[0011] Enter S2 until the spatial model of the field of view occlusion region for all cameras is established;

[0012] S5: In the BIM project model, combine the field-of-view model of each camera with its corresponding field-of-view occlusion area spatial model to generate the camera BIM field-of-view coverage model of the monitoring area to be identified.

[0013] As a preferred embodiment of the present invention, the field of view model in S1 is a three-dimensional parametric model, and a bottom plane P perpendicular to the field of view normal is provided at the center point of the bottom arc surface of the field of view model. E .

[0014] As a preferred embodiment of the present invention, step S2 employs a spatial segmentation-based secondary collision detection method to obtain the association relationship between the field of view model and other objects, including the following steps:

[0015] S21: Obtain the spatial cuboid corresponding to the field of view model, and output the object objects that intersect with the spatial cuboid as a set S1;

[0016] S22: Analyze the objects in the set S1 in sequence to determine the relationship between the field of view model and the spatial model of each object;

[0017] If the spatial model is completely inside the field of view model, add the current spatial model to the occlusion set S2 of the field of view model;

[0018] If the spatial model is partially inside the field of view model, obtain the intersection spatial model of the current spatial model and the field of view model, and add the intersection spatial model to the occlusion set S2 of the field of view model.

[0019] As a preferred embodiment of the present invention, step S21 further includes: when the object is of a transparent material type, removing it from the set S1.

[0020] As a preferred embodiment of the present invention, step S3 uses the camera as a point light source to capture the central outline of the spatial cuboid corresponding to the occluder perpendicular to the field of view normal, and draws the shadow boundary line of the occluder on the bottom plane of the field of view model based on the central outline.

[0021] As a preferred embodiment of the present invention, the drawing of the shadow boundary line in S3 includes the following steps:

[0022] S31: Obtain the starting coordinates of the field of view model and the field of view normal vector;

[0023] S32: Obtain the vertex set of the spatial cuboid corresponding to the occlusion object in the field of view model, calculate the center coordinates of the spatial cuboid, and the distance D between the starting point coordinates and the center coordinates. c ;

[0024] S33: At the stated center coordinates, create a plane P perpendicular to the field-of-view normal vector. c The spatial cuboid is obtained in plane P. c The boundary line of the cross section;

[0025] S34: Obtain the set of endpoints on the boundary line of the cross section, and calculate the distance D between the starting point coordinates and each endpoint in the endpoint set. s ;

[0026] S35: Calculate the ray vector originating from the stated starting point coordinates and passing through the stated endpoints, and draw a line along the direction of the ray vector with a length of D′. s The straight line segment, and the straight line segment intersected with the bottom plane P of the field of view model. E The intersection point is named the shaded point;

[0027] Among them, D′ s =D s ×L / D c L is the farthest effective viewing distance of the field of view model; P E The bottom plane of the field normal of the field model;

[0028] S36: Connect each shaded point sequentially to generate the cross-sectional boundary line on the bottom plane P. E The shadow boundary line on the top.

[0029] As a preferred embodiment of the present invention, step S4 creates a spatial hollow body by stretching the central contour, and then constructs a shadow hollow body according to the shadow boundary, which together constitutes a spatial model of the field of view occlusion area of ​​the occluder.

[0030] As a preferred embodiment of the present invention, the construction of the spatial model of the field of view occlusion region in S4 includes the following steps:

[0031] S41: Obtain the boundary line of any surface on the current occluding space cuboid, and the stretch length corresponding to the surface, and create a hollow object G1 that is exactly the same as the space cuboid;

[0032] S42: Obtain the cross-sectional boundary line and the shadow boundary line, and connect the corresponding endpoints to establish the shadow hollow body G2 of the occluder;

[0033] S43: Combine the hollow object G1 and the hollow shadow G2 of the current occlusion object to generate the spatial model G′ of the field of view occlusion region of the current occlusion object.

[0034] As a preferred embodiment of the present invention, step S5 includes the following steps:

[0035] S51: Establish a set of spatial models of the field-of-view occlusion regions of all occlusion objects in the set of occlusion objects.G′ ;

[0036] Wherein, the set of spatial models of the field of view occlusion region S G′ ={G′1,...,G′ i ,...,G′ M}, where M is the number of elements in the occlusion set;

[0037] S52: Targeting S G′ Collision detection is performed on the spatial models of the occluded regions in each field of view. If G′ i With G′ j If there is an intersection, then obtain the intersection G′. u and replace S G′ G′ in i With G′ j ;

[0038] S53: Sequentially combine the field-of-view models and the set of field-of-view occlusion region spatial models of each camera. G′ The elements in the model are used to generate the camera BIM field-of-view coverage model of the monitored area to be identified.

[0039] A BIM-based field-of-view occlusion region rapid identification device includes at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to perform any of the methods described above.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] This invention deploys camera field-of-view models within the BIM project model of the area to be monitored, sequentially acquiring the set of occlusions within each camera field-of-view model. Then, along the direction perpendicular to the normal of the corresponding camera field-of-view model, it draws the center outline of each occlusion and the shadow boundary line on the bottom plane of the field-of-view model, fusing them to create a spatial model of the occlusion area of ​​each occlusion. After connection processing, it achieves video simulation coverage of the area to be monitored. This invention essentially guarantees the realism and accuracy of the coverage simulation results, greatly improving the work efficiency of designers and overcoming the problems of cumbersome calculation and design processes, large workload, and difficulty in realistically presenting the coverage of the monitored area in existing technologies. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating a method for rapid identification of field-of-view occlusion areas based on BIM, as described in Embodiment 1 of the present invention.

[0043] Figure 2This is a three-dimensional schematic diagram of the camera field of view parameterization model containing the bottom plane PE in the BIM-based rapid identification method for occlusion areas described in Embodiment 3 of the present invention.

[0044] Figure 3 This is a schematic diagram of the camera's field of view and the scene of the obstruction in a BIM-based method for rapid identification of occlusion areas according to Embodiment 3 of the present invention.

[0045] Figure 4 This is a schematic diagram of the spatial model scene of the field of view occlusion region in the BIM-based rapid identification method for field of view occlusion regions described in Embodiment 3 of the present invention.

[0046] Figure 5 This is a schematic diagram of the cross-sectional contour boundary and the contour shadow boundary in a BIM-based method for rapid identification of field-of-view occlusion areas as described in Embodiment 3 of the present invention.

[0047] Figure 6 This is a schematic diagram of the fusion of the built-in hollow body of the field of view occlusion region in the BIM-based rapid identification method for field of view occlusion regions described in Embodiment 3 of the present invention.

[0048] Figure 7 This is a schematic diagram of the cropped camera field of view model in the BIM-based method for rapid identification of occlusion areas described in Embodiment 3 of the present invention.

[0049] Figure 8 This is a schematic diagram of the structure of a BIM-based field-of-view occlusion area rapid identification device, which utilizes the BIM-based field-of-view occlusion area rapid identification method described in Embodiment 2 of the present invention, as shown in Embodiment 4 of the present invention. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0051] Example 1

[0052] like Figure 1 As shown, a method for rapid identification of field-of-view occlusion regions based on BIM includes the following steps:

[0053] S1: In the BIM project model of the area to be monitored, deploy the field-of-view models of each camera.

[0054] S2: Select the field of view models of each camera in sequence, traverse the association relationship between the current field of view model and other objects in the project model, and generate a set of occlusions associated with the current field of view model.

[0055] S3: Along the direction perpendicular to the normal of the current field of view model, extract the spatial cuboid center outline of each occluder in the set of occluders, and draw the shadow boundary line of the center outline located on the bottom plane of the field of view model.

[0056] S4: Based on the central contour and shadow boundary line of each occluder, establish a spatial model of the occlusion region of each occluder in the current field of view model;

[0057] Enter S2 until the spatial model of the field of view occlusion region for all cameras is established.

[0058] S5: In the BIM project model, combine the field-of-view model of each camera with its corresponding field-of-view occlusion area spatial model to generate the camera BIM field-of-view coverage model of the monitoring area to be identified.

[0059] Example 2

[0060] This embodiment is a specific implementation of the BIM-based method for rapid identification of field-of-view occlusion areas described in Embodiment 1, including the following steps:

[0061] S1: In the BIM project model of the area to be monitored, deploy the field-of-view models of each camera.

[0062] The field of view model is a three-dimensional parametric model, and a bottom plane P perpendicular to the field of view normal is provided at the center point of the bottom arc surface of the field of view model. E .

[0063] S2: Sequentially select the field-of-view models of each camera, traverse the association relationships between the current field-of-view model and other objects in the project model, and generate a set of occlusions associated with the current field-of-view model. That is, use a spatial segmentation-based secondary collision detection method to obtain the association relationships between the field-of-view model and other objects, specifically including the following steps:

[0064] S21: Obtain the spatial cuboid corresponding to the field of view model, and output the object objects that intersect with the spatial cuboid as a set S1; when the object object is a transparent material type, remove it from the set S1.

[0065] S22: Analyze the objects in the set S1 in sequence to determine the relationship between the field of view model and the spatial model of each object.

[0066] If the spatial model is completely inside the field of view model, add the current spatial model to the occlusion set S2 of the field of view model.

[0067] If the spatial model is partially inside the field of view model, obtain the intersection spatial model of the current spatial model and the field of view model, and add the intersection spatial model to the occlusion set S2 of the field of view model.

[0068] S3: Along the direction perpendicular to the normal of the current field of view model, extract the spatial cuboid center contour of each occluder in the set of occluders, and draw the shadow boundary line of the center contour on the bottom plane of the field of view model. That is, by using the camera as a point light source, extract the spatial cuboid center contour of the corresponding occluder perpendicular to the field of view normal, and draw the shadow boundary line of the occluder on the bottom plane of the field of view model based on the center contour. This specifically includes the following steps:

[0069] S31: Obtain the starting coordinates of the field of view model and the field of view normal vector.

[0070] S32: Obtain the vertex set of the spatial cuboid corresponding to the occlusion object in the field of view model, calculate the center coordinates of the spatial cuboid, and the distance D between the starting point coordinates and the center coordinates. c .

[0071] S33: At the stated center coordinates, create a plane P perpendicular to the field-of-view normal vector. c The spatial cuboid is obtained in plane P. c The boundary line of the cross section.

[0072] S34: Obtain the set of endpoints on the boundary line of the cross section, and calculate the distance D between the starting point coordinates and each endpoint in the endpoint set. s .

[0073] S35: Calculate the ray vector originating from the stated starting point coordinates and passing through the stated endpoints, and draw a line along the direction of the ray vector with a length of D′. s The straight line segment, and the straight line segment intersected with the bottom plane P of the field of view model. E The intersection point is named the shaded point.

[0074] Among them, D′ s =D s ×L / D c L is the farthest effective viewing distance of the field of view model; P E Let be the bottom plane of the field normal of the field model.

[0075] S36: Connect the shaded points sequentially to generate the cross-sectional boundary line on the bottom plane P. E The shadow boundary line on the top.

[0076] S4: Based on the central contour and shadow boundary line of each occluder, establish the field-of-view occlusion area spatial model of each occluder in the current field-of-view model; proceed to S2 until the field-of-view occlusion area spatial model of all cameras corresponding to the field-of-view models is established.

[0077] Specifically, a boundary hollow body is created by stretching based on the central contour, and a shadow hollow body is constructed based on the shadow boundary. This is then combined with the solid body of the occluding object's model to form a spatial model of the occluding object's field of view occlusion region. The process includes the following steps:

[0078] S41: Obtain the boundary line of any surface on the current occluding space cuboid, and the stretch length corresponding to the surface, and create a hollow object G1 that is exactly the same as the space cuboid.

[0079] S42: Obtain the cross-sectional boundary line and the shadow boundary line, and connect the corresponding endpoints to establish the shadow hollow body G2 of the occluder.

[0080] S43: Combine the hollow object G1 and the hollow shadow G2 of the current occlusion object to generate the spatial model G′ of the field of view occlusion region of the current occlusion object.

[0081] S5: In the BIM project model, combine the field-of-view model of each camera with its corresponding field-of-view occlusion area spatial model to generate the camera BIM field-of-view coverage model of the monitoring area to be identified.

[0082] S51: Establish a set of spatial models of the field-of-view occlusion regions of all occlusion objects in the set of occlusion objects. G′ ;

[0083] Wherein, the set of spatial models of the field of view occlusion region S G′ ={G′1,...,G′ i ,...,G′ M}, where M is the number of elements in the set of occluders.

[0084] S52: Targeting S G′ Collision detection is performed on the spatial models of the occluded regions in each field of view. If G′ i With G′ j If there is an intersection, then obtain the intersection G′. u and replace S G′ G′ in i With G′ j .

[0085] S53: Sequentially combine the field-of-view models and the set of field-of-view occlusion region spatial models of each camera. G′ The elements in the model are used to generate the camera BIM field-of-view coverage model of the monitored area to be identified.

[0086] Example 3

[0087] This embodiment is a practical application of the BIM-based method for rapid identification of field-of-view occlusion areas described in Embodiment 2, and includes the following process:

[0088] S11. In the Revit family library environment, construct a camera field-of-view parametric BIM family type with a curved bottom and a conical solid shape. Model parameters include the farthest effective monitoring distance L, the maximum horizontal angle α, and the maximum vertical angle β. Simultaneously, at the center point of the bottom curved surface, create a bottom plane P along a direction perpendicular to the field-of-view normal. E , specifically Figure 2 As shown.

[0089] S12. In the Revit project environment, load the camera's field of view model family library, set up and rotate the field of view model family instance, and set L=100m, α=20°, β=20° in sequence.

[0090] S13. Draw a cube, a sphere, and a cuboid with non-transparent material in sequence, which will serve as occlusions B1, B2, and B3 in the field of view model, respectively, as shown below. Figure 3 As shown. Among them, B1 and B2 are entirely located within the field of view model, while B3 is partially contained within the field of view model.

[0091] S21. Obtain the boundary cuboid of the field of view model, traverse other objects that have a collision relationship with the cuboid, and form a set of associated objects S1 = {B1, B2, B3}.

[0092] S22. Compare and determine the association between the field of view model and the objects in set S1. Based on the spatial model inclusion relationship, add B1 and B2 to the occlusion set S2. Simultaneously, obtain the intersection U1 of B3 and the field of view model, forming S2 = {B1, B2, U1}, as detailed below. Figure 4 As shown.

[0093] S31. Obtain the starting coordinates O of the field of view model. Based on the maximum horizontal angle α = 20°, the maximum vertical angle β = 20°, and the installation tilt angle... Calculate the field-of-view normal vector V based on the field-of-view parameter value of horizontal rotation angle ω = 0°. c .

[0094] S32. Pick the boundary cuboid of occlusion B1 and its vertex set S. oc1 ={O B11 O B12 O B13 O B14 O B15 O B16 O B17 OB18 Confirm the coordinates O of the center of the cuboid space. c1 And calculate O and O c1 The spacing D between them c1 =83.52m.

[0095] S33, in O c1 Create a vector V perpendicular to the field of view normal. c plane P c1 Pick the boundary line L of the cross section of the boundary cuboid on plane P. s1 .

[0096] S34, Obtain L s1 The set of endpoints S on os1 ={O S11 O S12 O S13 O S14}, calculate the field of view starting point O and S in sequence. os1 Point O in the middle s1 The spacing D between them s1 ={D s11 D s12 D s13 D s14}

[0097] S35, Starting from O, O s1 The rendezvous point is a point on the line, and the ray vector information set V is obtained. s1 According to D s1 The length information in the data is taken from O as the starting point and along the corresponding V. s1 Vector direction, drawing length D′ s1 =100.51m(D s1 ×L / D c1 Find the straight line segment O. s1 The meeting point is on the bottom plane P. E Shaded point O′ s1 This forms the set of shaded points S′ os1 ={O′ S11 O′ S12 O′ S13 O′ S14}

[0098] S36. Draw straight line segments in sequence and connect the set of shaded points S′. os1 The points in the section form the boundary line L of the cross section. s1 At the bottom plane P E The shadow boundary line L′ on s1 , specifically Figure 5 As shown.

[0099] S41. Pick the bottom plane boundary line of the boundary cuboid B1, and extrude it to create a hollow boundary cuboid G with a height of 6m. 11 The video occlusion area of ​​the B1 object itself.

[0100] S42, Pick the section boundary line L s1 and the shaded boundary line L′ s1 , fusion to create hollow body G 21 This refers to the video occlusion area caused by the B1 object blocking the view.

[0101] S43, Connecting solid body G1 and hollow body G of the field of view model. 11 and the shadow hollow body G 21 This forms the spatial model G′1 of the occlusion region of the occlusion object B1, specifically as follows: Figure 6 As shown.

[0102] S5. Referring to S302 to S4033, sequentially obtain the field-of-view occlusion region spatial models G′2 and G′3 of B2 and U1 in the occlusion object set S2, and complete the video simulation coverage simulation within the monitoring scene area of ​​a single camera. Specifically, as follows... Figure 7 As shown.

[0103] S6. Repeat S5 to obtain the visible field-of-view model of each camera in the field-of-view model and generate a video simulation coverage simulation of the monitoring area to be identified.

[0104] Example 4

[0105] like Figure 8 As shown, a BIM-based rapid field-of-view occlusion region identification device includes at least one processor, a memory communicatively connected to the at least one processor, and at least one input / output interface communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, which, when executed, enables the at least one processor to perform the BIM-based rapid field-of-view occlusion region identification method described in the foregoing embodiments. The input / output interface may include a display, keyboard, mouse, and USB interface for inputting and outputting data.

[0106] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0107] When the integrated units of this invention are implemented as software functional units and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this invention, or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapid identification of field-of-view occlusion regions based on BIM, characterized in that, Includes the following steps: S1: In the BIM project model of the area to be identified and monitored, set up the field of view model of each camera; S2: Select the field of view models of each camera in sequence, traverse the association relationship between the current field of view model and other objects in the project model, and generate a set of occluders associated with the current field of view model; S3: Along the direction perpendicular to the normal of the current field of view model, extract the spatial cuboid center outline of each occluder in the set of occluders, and draw the shadow boundary line of the center outline located on the bottom plane of the field of view model; S4: Based on the central contour and shadow boundary line of each occluder, establish a spatial model of the occlusion region of each occluder in the current field of view model; Enter S2 until the spatial model of the field of view occlusion region for all cameras is established; S5: In the BIM project model, the field-of-view model of each camera is combined with its corresponding field-of-view occlusion area spatial model to generate the camera BIM field-of-view coverage model of the monitoring area to be identified. S2 employs a spatial segmentation-based secondary collision detection method to obtain the association relationship between the field of view model and other objects, including the following steps: S21: Obtain the spatial cuboid corresponding to the field of view model, and output the object objects that intersect with the spatial cuboid as a set S1; S22: Analyze the objects in the set S1 in sequence to determine the relationship between the field of view model and the spatial model of each object; If the spatial model is completely inside the field of view model, add the current spatial model to the occlusion set S2 of the field of view model; If the spatial model is partially inside the field of view model, obtain the intersection spatial model of the current spatial model and the field of view model, and add the intersection spatial model to the occlusion set S2 of the field of view model.

2. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 1, characterized in that, The field-of-view model described in S1 is a three-dimensional parametric model, and a bottom plane P perpendicular to the field-of-view normal is provided at the center point of the bottom arc surface of the field-of-view model. E .

3. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 1, characterized in that, S21 also includes: when the object is of a transparent material type, removing it from the set S1.

4. A method for rapid identification of field-of-view occlusion regions based on BIM according to any one of claims 1-3, characterized in that, S3 uses the camera as a point light source to capture the central outline of the spatial cuboid corresponding to the occluder, which is perpendicular to the field of view normal, and draws the shadow boundary line of the occluder on the bottom plane of the field of view model based on the central outline.

5. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 4, characterized in that, The drawing of the shadow boundary line described in S3 includes the following steps: S31: Obtain the starting coordinates of the field of view model and the field of view normal vector; S32: Obtain the vertex set of the spatial cuboid corresponding to the occlusion object in the field of view model, calculate the center coordinates of the spatial cuboid, and the distance D between the starting point coordinates and the center coordinates. c ; S33: At the stated center coordinates, create a plane P perpendicular to the field-of-view normal vector. c The spatial cuboid is obtained in plane P. c The boundary line of the cross section; S34: Obtain the set of endpoints on the boundary line of the cross section, and calculate the distance D between the starting point coordinates and each endpoint in the endpoint set. s ; S35: Calculate the ray vector originating from the stated starting point coordinates and passing through the stated endpoints, and draw a line along the direction of the ray vector with a length of D′. s The straight line segment, and the straight line segment intersected with the bottom plane P of the field of view model. E The intersection point is named the shaded point; Among them, D′ s =D s ×L / D c L represents the farthest effective viewing distance of the field of view model; P E Let be the bottom plane of the field of view normal of the field of view model; S36: Connect each shaded point sequentially to generate the cross-sectional boundary line on the bottom plane P. E The shadow boundary line on the top.

6. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 5, characterized in that, S4 creates a spatial hollow body by stretching the central contour, and then constructs a shadow hollow body based on the shadow boundary, combining them to form a spatial model of the field of view occlusion area of ​​the occluder.

7. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 6, characterized in that, The construction of the spatial model of the field of view occlusion region described in S4 includes the following steps: S41: Obtain the boundary line of any surface on the current occluding space cuboid, and the stretch length corresponding to the surface, and create a hollow object G1 that is exactly the same as the space cuboid; S42: Obtain the cross-sectional boundary line and the shadow boundary line, and connect the corresponding endpoints to establish the shadow hollow body G2 of the occluder; S43: Combine the hollow object G1 and the hollow shadow G2 of the current occlusion object to generate the spatial model G′ of the occlusion area of ​​the current occlusion object.

8. The method for rapid identification of field-of-view occlusion regions based on BIM according to claim 1, characterized in that, S5 includes the following steps: S51: Establish a set of spatial models of the field-of-view occlusion regions of all occlusion objects in the set of occlusion objects. G′ ; Wherein, the set of spatial models of the field of view occlusion region S G′ ={ G′1,...,G′ i ,...,G′ M }, where M is the number of elements in the occlusion set; S52: Targeting S G′ Collision detection is performed on the spatial model of each occlusion region in the field of view. If G′ i With G′ j If there is an intersection, then obtain the intersection G′. u and replace S G′ G′ in i With G′ j ; S53: Sequentially combine the field-of-view models of each camera and the set of spatial models of the field-of-view occlusion regions S. G′ The elements in the model are used to generate the camera BIM field-of-view coverage model of the monitored area to be identified.

9. A BIM-based device for rapid identification of field-of-view occlusion areas, characterized in that, It includes at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1 to 8.

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