WO2018192419A1 - 可见面判定方法、反向射线追踪方法及装置 - Google Patents

可见面判定方法、反向射线追踪方法及装置 Download PDF

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Publication number
WO2018192419A1
WO2018192419A1 PCT/CN2018/082957 CN2018082957W WO2018192419A1 WO 2018192419 A1 WO2018192419 A1 WO 2018192419A1 CN 2018082957 W CN2018082957 W CN 2018082957W WO 2018192419 A1 WO2018192419 A1 WO 2018192419A1
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Prior art keywords
plane
determined
signal
determining
planes
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PCT/CN2018/082957
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English (en)
French (fr)
Inventor
陈诗军
董承风
陈强
王慧强
陈大伟
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中兴通讯股份有限公司
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Priority to EP18787149.6A priority Critical patent/EP3614584A4/en
Publication of WO2018192419A1 publication Critical patent/WO2018192419A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/18—Network planning tools
    • H04W16/20—Network planning tools for indoor coverage or short range network deployment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3912—Simulation models, e.g. distribution of spectral power density or received signal strength indicator [RSSI] for a given geographic region
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel

Definitions

  • the present disclosure relates to a communication technology, and in particular to a visible surface determination method, a reverse ray tracing method and apparatus.
  • channel simulation can be used to propagate the signal for analysis.
  • Channel simulation can use simulation to simulate the true channel environment of signal propagation.
  • Representative channel simulation can be based on ray tracing techniques.
  • ray tracing techniques the inverse ray tracing algorithm can more accurately calculate the channel characteristics in each ray path.
  • the existence of the diffraction phenomenon makes the creation of mirror points infinite possibilities, the establishment of a large number of mirror points and the resulting large number of intersection tests increase the computational complexity and reduce the efficiency of judgment.
  • the present disclosure provides a method for determining a visible surface, including the steps of: acquiring plane information of a plane to be determined in a target space; and detecting, for a first to-be-determined plane, whether there is a second to-be-determined plane such that the first to-be-determined Each line segment formed by each plane bump in the determination plane and the signal transmission point passes through the second to-be-determined plane, wherein the first to-be-determined plane and the second to-be-determined plane are Determining any two planes in the plane; determining whether the first to-be-determined plane is a visible surface according to the detection result; and performing the detecting step and the determining step for the next to-be-determined plane until all the locations are traversed A determination plane is described, wherein the next to-be-determined plane is one of the undetermined planes in the plane to be determined.
  • the present disclosure also provides a reverse ray tracing method, the method comprising the steps of: acquiring plane information of a plane to be determined in a target space; and detecting whether there is a second to-be-determined plane for the first to-be-determined plane Passing each line segment formed by each plane bump in the first to-be-determined plane and the signal transmission point through the second to-be-determined plane, wherein the first to-be-determined plane, the second The plane to be determined is any two planes in the plane to be determined; determining whether the first to-be-determined plane is a visible surface according to the detection result; performing the detecting step and the determining step for the next to-be-determined plane until Traversing all of the to-be-determined planes to obtain a set of visible planes in the target space, wherein the next to-be-determined plane is one of the undetermined planes in the to-be-determined plane; and according to the signal The position of the transmitting point and the position of the signal receiving point, and ray propagation calculation
  • the present disclosure further provides a visible surface determining apparatus, comprising: an acquiring unit configured to acquire plane information of a plane to be determined in a target space; and a detecting unit configured to detect whether the plane is to be determined for the first to be determined There is a second to-be-determined plane such that each of the line segments formed by the plane bumps in the first to-be-determined plane and the signal transmission point passes through the second to-be-determined plane, wherein the first to-be-determined plane a determination plane, the second to-be-determined plane is any two planes in the plane to be determined; and a determining unit configured to determine whether the first to-be-determined plane is a visible surface according to the detection result, wherein The detecting unit and the determining unit are further configured to perform the detecting operation and the determining operation for the next to-be-determined plane until all of the to-be-determined planes are traversed, wherein the next to-be-determined plane is the A plane in the plane to be determined in the undetermined plane.
  • the present disclosure also provides a reverse ray tracing apparatus comprising the visible surface determining apparatus as described above, and further comprising: an acquisition unit communicatively coupled to the visible surface determining apparatus, and configured to acquire a target A collection of visible faces in space; a propagation calculation unit configured to perform a ray propagation calculation for each of the visible faces in the set to determine a corresponding signal propagation path based on the location of the signal transmission point and the location of the signal reception point.
  • the present disclosure also provides a computer readable storage medium having stored thereon a computer program that, when executed by a processor, causes the processor to perform a visible surface determination method or a reverse according to the present disclosure Ray tracing method.
  • FIG. 1 is a flow chart showing the steps of a method of determining a visible surface according to an embodiment of the present disclosure
  • FIG. 2 is a flowchart showing an implementation of a method of determining a visible surface according to an embodiment of the present disclosure
  • FIG. 3 is a flow chart of steps of a reverse ray tracing method in accordance with an embodiment of the present disclosure
  • FIG. 4 is a flow chart showing an implementation of a reverse ray tracing method in accordance with an embodiment of the present disclosure
  • Figure 5 is a schematic diagram of the determination of the visible surface in the positioning scene 1;
  • Figure 6 is a spatial layout diagram of the positioning scene 1;
  • Figure 7 is a schematic diagram of the determination of the visible surface in the positioning scene 2;
  • Figure 8 is a spatial layout diagram of the positioning scene 2
  • Figure 9 is a schematic diagram of the determination of the visible surface in the positioning scene 3;
  • Figure 10 is a spatial layout diagram of the positioning scene 3;
  • FIG. 11 is a schematic structural diagram of a visible surface determining apparatus according to an embodiment of the present disclosure.
  • FIG. 12 is a schematic structural diagram of a reverse ray tracing apparatus according to an embodiment of the present disclosure.
  • channel simulation can be used to propagate the signal for analysis.
  • Channel simulation can use simulation to simulate the true channel environment of signal propagation.
  • Representative channel simulations can be based on ray tracing techniques.
  • ray tracing techniques the inverse ray tracing algorithm can more accurately calculate the channel characteristics in each ray path.
  • the existence of diffraction phenomena makes the creation of mirror points infinite possibilities. The establishment of a large number of mirror points and the resulting large number of intersection tests increases the overhead of computing the ray tracing propagation path and reduces the efficiency of the decision.
  • projection intersection determination can be used to determine which planes in the environment are invisible (occluded) so that reflection, refraction, and diffraction do not occur at the plane to reduce the need for mirror points to be established.
  • the amount, and the cost of calculating the ray tracing propagation path it is necessary to calculate three projections for each object in the environment (projecting in three directions of X-axis, Y-axis, and Z-axis) to obtain three projection planes (in XY plane, XZ plane, YZ).
  • the projection surface on the plane), and for each face of the object multiple determinations are made using the three projection faces of the object to determine if the face is a visible face. This introduces a new computational cost while reducing the overhead of the ray tracing propagation path, and the overhead is large.
  • FIG. 1 is a flow chart showing the steps of a method of determining a visible surface in accordance with an embodiment of the present disclosure.
  • an embodiment of the present disclosure provides a method for determining a visible surface, which includes steps S11-S14.
  • step S11 plane information of the plane to be determined in the target space is acquired.
  • step S12 for the first to-be-determined plane, detecting whether there is a second to-be-determined plane such that each line segment formed by each plane bump in the first to-be-determined plane and the signal transmission point passes through The second to-be-determined plane, wherein the first to-be-determined plane and the second to-be-determined plane are any two planes in the to-be-determined plane.
  • step S13 it is determined whether the first to-be-determined plane is a visible surface according to the detection result.
  • step S14 the detecting step S12 and the determining step S13 are performed for the next to-be-determined plane until all of the to-be-determined planes are traversed.
  • the visible surface determination method of the embodiment of the present disclosure it is possible to avoid calculating three projections for each object in the projection intersection determination to obtain three projection planes thereof (projections on the XY plane, the XZ plane, the YZ plane) Face), and avoiding each of the faces of the object, using the three projection faces of the object to make multiple determinations to determine whether the face is a visible face, and thus greatly reducing the calculation accuracy while ensuring Calculate the overhead of the ray tracing propagation path.
  • the plane to be determined includes a plane in which the surfaces of the object in the target space are located, wherein the three planes to be determined intersect at one plane bump.
  • the location information of the transmission point may also be acquired in the above step S11.
  • a spatial model of the three-dimensional visualization may be established for the space to be located.
  • the space to be positioned is also referred to as a target space, and some objects are arranged in the target space, and the surfaces of the objects can reflect, refract, diffract, etc., the signals in the propagation, thereby affecting the propagation path of the signals in various ways.
  • the surfaces of the objects constitute the plane to be determined, and the intersection of each of the planes to be determined and any other two planes to be determined constitutes a plane bump.
  • the coordinates of the network element node (ie, the transmission point) and the coordinates of the plane bump are known conditions and can be directly obtained.
  • the visible surface refers to the plane from which the reverse ray from the receiving point can be reflected, refracted or diffracted to reach the emission point.
  • the invisible surface refers to all planes other than the visible surface in the plane to be determined.
  • step S12 for the first to-be-determined plane, detecting whether there is a second to-be-determined plane such that each plane bump in the first to-be-determined plane is connected to the signal transmission point
  • the step of the line segments passing through the second to-be-determined plane may include: reading a plane equation of the first to-be-determined plane and obtaining coordinates of each plane bump in the first to-be-determined plane; Each of the planar bumps is respectively connected to the signal emission point to obtain a line segment respectively corresponding to the planar bumps; and detecting whether there is the second portion intersecting the respective line segments in the to-be-determined plane The plane to be determined.
  • the first to-be-determined plane and the second to-be-determined plane described at step S12 are any two planes in the plane to be determined, in other words, the first to be determined.
  • the plane is one of the planes to be determined
  • the second plane to be determined is any other plane in the plane to be determined that is different from the plane to be determined.
  • the step of determining, according to the detection result, whether each of the to-be-determined planes is a visible surface, according to the detection result may include: determining, in the case that the detection result is that the second to-be-determined plane exists, determining The first to-be-determined plane is an invisible plane; and in the case that the detection result is that the second to-be-determined plane does not exist, determining that the first to-be-determined plane is a visible plane.
  • the detecting step and the determining step are performed for the next to-be-determined plane until all of the to-be-determined planes are traversed, wherein the next to-be-determined plane is A plane in the undecided plane in the decision plane is described. That is, all the to-be-determined planes in the target space are traversed at step S14 to determine whether each of the to-be-determined planes is a visible plane, thereby obtaining a set of all visible faces in the target space.
  • the first to-be-determined plane is blocked by one or more of the other to-be-determined planes, that is, The first to-be-determined plane is not visible, and thus the signal transmitted from the signal transmission point does not pass through the first to-be-determined plane.
  • FIG. 2 is a flow chart showing an implementation of a method of determining a visible surface in accordance with an embodiment of the present disclosure.
  • a method for determining whether a plane to be determined in a target space may include the following steps S201-S210.
  • step S201 plane information of the plane to be determined in the target space and position information of the transmission point T are acquired.
  • the position information of the transmission point T includes the position coordinates of the transmission point T.
  • step S202 it is judged whether all the planes to be determined in the target space are traversed, if both are traversed, go to step S210, otherwise go to step S203.
  • a plane equation of a plane to be determined is read, and the coordinates of the bumps in the plane to be determined are obtained.
  • One of the planes to be determined that is read in may be referred to as a first to-be-determined plane.
  • each bump in the plane to be determined is respectively connected to the transmission point T to obtain n line segments respectively corresponding to the respective bumps in the plane to be determined, where n is the plane to be determined The number of bumps in the middle.
  • step S205 the equation of the line of each of the n line segments obtained in step S204 and the range of values of the equation variables are obtained.
  • step S206 the line equation of the n line segments obtained in step S205 is tested for intersection with each of the target planes except the first to-be-determined plane.
  • step S207 if there is any one of the tested planes to be determined such that the line equations of the n line segments intersect, and the coordinate value range of the intersection point is within the value range of the variable of the line segment, then the step S203 is explained.
  • the first to-be-determined plane read in is not visible, and the process goes to step S208; otherwise, the first to-be-determined plane is visible, and the process goes to step S209.
  • step S208 the first to-be-determined plane is marked as false (false), and the flow proceeds to step S202.
  • step S209 the first to-be-determined plane is marked as true (true), and the flow proceeds to step S202.
  • step S210 a set of all visible faces in the target space is obtained.
  • the visible surface determination method provided by the above embodiment can greatly reduce the plane in which propagation analysis is required, thereby accelerating the speed of ray tracing and reducing the computational overhead.
  • FIG. 3 is a flow chart of the steps of a reverse ray tracing method in accordance with an embodiment of the present disclosure.
  • an embodiment of the present disclosure further provides a reverse ray tracing method using a visible surface determination method according to an embodiment of the present disclosure, that is, the method includes steps S11-S14 shown in FIG. And S31-S32.
  • steps S11-S14 are performed to acquire a set of visible faces in the target space. Steps S11-S14 have been described in detail with reference to Fig. 1, and thus the description will not be repeated here.
  • step S31 a set of visible faces in the target space is acquired.
  • a ray propagation calculation is performed on each of the visible faces in the set to determine a corresponding signal propagation path based on the location of the signal transmission point and the location of the signal reception point.
  • the inverse ray tracing method provided by the embodiment of the present disclosure is capable of acquiring a set of visible faces in the target space to pre-exclude a large number of invisible faces in the target space, and then according to the position of the signal transmitting point and the position of the signal receiving point, The ray propagation calculation is performed for each visible surface, so that the signal propagation path between the signal transmission point and the signal reception point can be determined.
  • the position of the transmission point and the position of the reception point can be used as known conditions to study the propagation path of the signal between each pair of signal transmission points and signal reception points.
  • the positions of the signal transmission point and the signal receiving point can be interchanged and the channel still exists. At this time, the signal transmission direction is opposite.
  • a signal of a positioning signal of a positioning network element can also be known.
  • Signal parameter characteristics such as intensity, transmit power, signal frequency, etc., thereby quantizing the signal in the target space based on these signal parameter characteristics.
  • the reverse ray tracing method provided by the embodiment of the present disclosure further The method may include: determining a loss of signal strength of the transmitted signal by the signal propagation path; and retaining the signal propagation path if a signal strength of the signal after the loss is greater than or equal to a preset threshold And deleting the signal propagation path if the signal strength of the signal after the loss is less than the predetermined threshold.
  • the signal intensity will be attenuated to different degrees. If the signal is still strong when it reaches the signal receiving point after being attenuated, so that it can be effectively detected by the receiver, the corresponding channel can be reserved as a signal transmission path. Otherwise, if the signal strength is relatively small when the signal reaches the signal receiving point after being attenuated, so that it cannot be effectively detected by the receiver, the corresponding channel is no longer available and needs to be deleted.
  • the inverse ray tracing calculation method provided by the embodiment of the present disclosure can effectively simulate the propagation path of the signal in space, establish a channel model, and calculate the parameters of each path according to the electromagnetic theory, thereby realizing accurate simulation of the channel. Moreover, the determination based on the visible surface can greatly reduce the planes that need to be propagated, thereby speeding up the ray tracing and reducing the computational overhead.
  • FIG. 4 is a flow chart of an implementation of a reverse ray tracing method in accordance with an embodiment of the present disclosure.
  • the reverse ray tracing method provided in this embodiment may include the following steps S401-S412.
  • the location information of the network element is obtained, that is, the three-dimensional position coordinates of the transmission point of the network element are obtained.
  • step S403 signal parameter characteristics such as signal strength, transmission power, and signal frequency of the positioning signal of the network element are acquired.
  • the location information of the terminal is acquired, that is, the three-dimensional position coordinates of the reception point are obtained.
  • the set V of all visible faces is obtained by the visible plane determination method (i.e., steps S11-S14 shown in Fig. 1) provided by the above embodiment.
  • the set V of visible faces is a subset of the set U to be determined above, and thus M ⁇ N.
  • the meeting may be set from the visible surface i V taken, successively using reflection, refraction and diffraction mode, is calculated for the visible rays for propagation surface i and is set in accordance with the reflection, refraction and diffraction times, A ray path for the visible surface is obtained, which is stored in the ray path table of the terminal (ie, the receiving point).
  • a loss parameter of the signal during propagation along the ray propagation path is determined based on the signal propagation path and existing direct, reflection, refraction, and diffraction loss calculation formulas.
  • step S408 it is determined whether the signal strength satisfies the signal strength constraint by comparing the signal strength of the signal subjected to the loss with a preset signal strength minimum value (ie, a threshold value), that is, whether the signal strength is Greater than or equal to the preset threshold. If the result of the determination is "YES”, it indicates that the constraint condition is satisfied, and the process proceeds to step S409. If the result of the determination is "NO”, it means that the constraint is not satisfied, and the process goes to step S410.
  • a preset signal strength minimum value ie, a threshold value
  • step S409 the constraint condition is met, ie the signal strength is greater than or equal to the preset threshold, which indicates that the signal strength is still available for positioning, and the current signal propagation path and signal strength and its loss are saved for later calculation. Go to step S411.
  • step S410 if the constraint condition is not met, that is, the signal strength is less than the preset threshold, which indicates that the signal is no longer available for positioning, the path search is ended and the corresponding signal propagation path is deleted. Go to step S411.
  • step S412 it is judged whether or not i ⁇ M. If yes, go to step S406 to continue analyzing the ray propagation path for the next visible surface; if not, the ray propagation path has been analyzed for all visible surfaces, ending the flow.
  • FIG. 5 is a schematic diagram of the determination of the visible surface in the positioning scene 1.
  • T is a transmission point
  • the plane ABCD is a plane to be determined.
  • the following is an example of judging a plane to be determined in the positioning scene 1 by using the visible plane determining method described with reference to FIGS. 1 and 2, for example.
  • the plane ABCD to be determined are described herein, and other steps are omitted.
  • the determining method may include: reading a plane equation of a spatial plane ABCD to be determined, and obtaining coordinates of each of the bumps A, B, C, and D; and each bump A, B of the spatial plane ABCD to be determined.
  • C, D are respectively connected with the transmission point T to obtain 4 line segments; obtain the linear equation of each line segment TA, TB, TC, TD, and the value range of the equation variable; use the obtained linear equation of 4 line segments Performing an intersection test with each of the faces other than the plane ABCD in the target space model; in the present embodiment, as shown in FIG.
  • the spatial plane ABCD is an invisible plane, and it is assumed that the spatial plane A'B'C'D' of the occlusion space plane ABCD is a visible plane.
  • the following is an example of performing a ray propagation calculation for a plane to be determined in the positioning scene 1 to determine a corresponding signal propagation path using the inverse ray tracing method described, for example, with reference to FIGS. 3 and 4.
  • the steps specific to the plane A'B'C'D' are described herein by way of example only, and other steps are omitted.
  • FIG. 6 is a spatial layout diagram of the positioning scene 1.
  • the ray propagation calculation is performed by reflection.
  • the propagation path of the signal is obtained by one reflection.
  • the emission point T creates a mirror point Mr according to the surface A'B'C'D'.
  • the intersection of B'C'D' is O, so that the signal propagation path from the transmission point T to the reception point R is T ⁇ O ⁇ R.
  • This path is stored in the ray path table of the terminal (ie, receiving point R).
  • FIG. 7 is a schematic diagram of the determination of the visible surface in the positioning scene 2.
  • T is a transmission point
  • the plane HIJK is a plane to be determined.
  • the following is an example of judging a plane to be determined in the positioning scene 2 by using the visible plane determining method described with reference to FIGS. 1 and 2, for example.
  • the plane to be determined HIJK are described herein, and other steps are omitted.
  • the determining method may include: reading a plane equation of a spatial plane HIJK to be determined, and obtaining coordinates of each of the bumps H, I, J, and K; and each bump H, I of the spatial plane HIJK to be determined.
  • J, K are respectively connected with the transmission point T to obtain 4 line segments; obtain the line equation of each line segment TH, TI, TJ, TK, and the value range of the equation variable; use the obtained linear equation of 4 line segments Perform intersection test with each face except the plane HIJK in the target space; as shown in FIG.
  • the spatial plane HIJK is a visible surface
  • the spatial plane MNN'M' is also a visible surface.
  • the following is an example of performing a ray propagation calculation for a plane to be determined in the positioning scene 2 to determine a corresponding signal propagation path using, for example, the inverse ray tracing method described with reference to FIGS. 3 and 4.
  • specific steps specific to the plane MNN 'M' are described herein by way of example only, and other steps are omitted.
  • FIG. 8 is a spatial layout diagram of the positioning scene 2.
  • the ray propagation calculation is performed for the visible surface MNN'M', for example, the propagation path of the signal in the indoor environment is obtained by two reflections.
  • the emission point T creates a mirror point Mr1 from the visible surface MNN'M'. It is found through the intersection test that there is an object 2 occlusion between the mirror point Mr1 and the receiving point R, so there is no directly reachable path.
  • the secondary mirror point Mr2 of the mirror point Mr1 is created. At this time, it is found that there is a directly reachable path Mr2 ⁇ R between the secondary mirror point Mr2 and R, and the connection of the Mr2 and R and the plane HIJK.
  • intersection point between the points is O
  • the intersection between the line connecting the point O and the mirror point Mr1 and the plane MNN'M' is O'
  • the signal propagation path from the transmission point T to the receiving point R is T ⁇ O' ⁇ O ⁇ R.
  • This path is stored in the ray path table of the terminal (ie, receiving point R).
  • FIG. 9 is a schematic diagram of the determination of the visible surface in the positioning scene 3.
  • T is a transmission point
  • a plane SXUV is a plane to be determined.
  • the following is an example of judging a plane to be determined in the positioning scene 3 by using the visible plane determining method described with reference to FIGS. 1 and 2, for example.
  • FIGS. 1 and 2 for example.
  • only specific steps relating to the plane SXUV to be determined are described herein, and other steps are omitted.
  • the determining method may include: reading a plane equation of a spatial plane SXUV to be determined, and obtaining coordinates of each of the bumps S, X, U, and V; and respective bumps S and X of the spatial plane SXUV to be determined.
  • U, V are respectively connected with the transmission point T to obtain 4 line segments; obtain the obtained linear equations of each line segment TS, TX, TU, TV, and the range of values of the equation variables; use the obtained 4 line segments
  • the line equation is tested for intersection with each of the faces other than the plane SXUV in the target space; as shown in Figure 9, there is a plane S'X'U'V' that intersects the line segments TS, TX but with the line segment TU
  • the TVs do not intersect, and there is no plane intersecting the four segments TS, TX, TU, and TV. This indicates that the spatial plane SXUV to be determined is a visible surface, thereby marking the spatial plane SXUV as true.
  • the spatial plane SXUV is a visible surface
  • the spatial plane QZZ'Q' and the spatial plane S'X'U'V' are also visible surfaces.
  • the following is an example of performing a ray propagation calculation for a plane to be determined in the positioning scene 3 to determine a corresponding signal propagation path using the inverse ray tracing method described, for example, with reference to FIGS. 3 and 4.
  • the specific steps specific to the plane QZZ'Q' are described here by way of example only, and other steps are omitted.
  • FIG. 10 is a spatial layout diagram of the positioning scene 3.
  • the ray propagation calculation is performed by reflection, for example, the propagation path of the signal in the indoor environment is obtained by two reflections.
  • object 2 the emission point T creates a mirror point Mr1 according to the visible plane QZZ'Q', and through the intersection test, it is found that there is an object 2 occlusion between the mirror points Mr1 and R, and there is no directly reachable path.
  • the visible plane S'X'U'V' of the object 1 the secondary mirror point Mr2 of the mirror point Mr1 is created. At this time, it is found that there are directly reachable paths Mr2 ⁇ R, Mr2 and between the secondary mirror points Mr2 and R.
  • the intersection between the line connecting R and the plane S'X'U'V' is O', and the intersection between the line connecting the point O' and the mirror point Mr1 and the plane QZZ'Q' is 0, thereby obtaining the slave point.
  • the signal propagation path from T to the receiving point R is T ⁇ O ⁇ O' ⁇ R. This path is stored in the ray path table of the terminal (ie, receiving point R).
  • Embodiments of the present disclosure provide a reverse ray tracing method that, in one aspect, converts two-dimensional ray tracing into three-dimensional ray tracing, further improving the accuracy of signal propagation analysis results.
  • it uses a lightweight cross-correlation-based visible surface decision algorithm to improve the use of reverse ray tracing algorithms to simulate the running speed of the signal propagation path, greatly reducing run time, and improving analysis efficiency.
  • FIG. 11 is a schematic structural view of a visible surface determining device according to an embodiment of the present disclosure.
  • an embodiment of the present disclosure further provides a visible surface determining apparatus, which is disposed in a computer device, and includes an obtaining unit 111, a detecting unit 112, and a determining unit 113.
  • the acquisition unit 111 is configured to acquire plane information of a plane to be determined in the target space.
  • the detecting unit 112 is configured to detect whether there is a second to-be-determined plane for the first to-be-determined plane, so that each line segment formed by the plane bumps in the first to-be-determined plane and the signal transmission point passes through The second to-be-determined plane, wherein the first to-be-determined plane and the second to-be-determined plane are any two planes in the to-be-determined plane.
  • the determining unit 113 is configured to determine whether the first to-be-determined plane is a visible surface based on the detection result.
  • the detecting unit 112 and the determining unit 113 are further arranged to perform the detecting operation and the determining operation for the next to-be-determined plane until all of the to-be-determined planes are traversed.
  • the plane to be determined includes a plane in which the surfaces of the objects in the target space are located, wherein the three planes to be determined intersect at one plane bump.
  • the acquisition unit 111 is further configured to acquire location information of the transmission point.
  • the detecting unit 112 is further configured to: read a plane equation of the first to-be-determined plane and obtain coordinates of each plane bump in the first to-be-determined plane; Connecting to the signal emission point respectively to obtain line segments respectively corresponding to the planar bumps; and detecting whether there is a second to-be-determined plane intersecting the respective line segments in the to-be-determined plane.
  • the determining unit 113 is further configured to: when the detection result is that the second to-be-determined plane exists, determine that the first to-be-determined plane is an invisible surface; and in the detection result, In the case where the second to-be-determined plane does not exist, it is determined that the first to-be-determined plane is a visible plane.
  • the visible surface determining apparatus of the embodiment of the present disclosure it is possible to avoid calculating three projections for each object in the projection intersection determination to obtain three projection planes thereof (projections on the XY plane, the XZ plane, the YZ plane) Face), and avoiding each of the faces of the object, using the three projection faces of the object to make multiple determinations to determine whether the face is a visible face, and thus greatly reducing the calculation accuracy while ensuring Calculate the overhead of the ray tracing propagation path.
  • FIG. 12 is a schematic structural diagram of a reverse ray tracing apparatus according to an embodiment of the present disclosure.
  • an embodiment of the present disclosure further provides a reverse ray tracing apparatus provided in a computer device, including the visible surface determining apparatus as described above, and further comprising a second acquiring unit 121 and propagation Calculation unit 122.
  • a second acquisition unit 121 is communicatively coupled to the visible surface determination device and configured to acquire a set of visible faces in the target space.
  • Propagation calculation unit 122 is arranged to perform a ray propagation calculation for each of the visible faces in the set to determine a corresponding signal propagation path based on the location of the signal transmission point and the location of the signal reception point.
  • the obtaining unit 121 is further configured to acquire location information of the transmitting point and location information of the receiving point.
  • the reverse ray tracing apparatus may further include a loss determining unit, a retaining unit, and a deleting unit.
  • the loss determination unit is arranged to determine the loss of the signal strength of the transmitted signal by the signal propagation path determined by the propagation calculation unit 122.
  • the reserve unit is configured to reserve the signal propagation path if a signal strength of the signal subjected to the loss is greater than or equal to a preset threshold.
  • the deleting unit is configured to delete the signal propagation path if a signal strength of the signal subjected to the loss after the signal is less than the predetermined threshold.
  • a software product stored in a storage medium (eg, ROM/RAM, disk,
  • the optical disc includes a number of instructions to cause a terminal device (which may be a cell phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the methods described in various embodiments of the present disclosure.

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Abstract

本公开提供了一种可见面判定方法、反向射线追踪方法及装置，其中，所述可见面判定方法包括步骤：获取目标空间中的待判定平面的平面信息；针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；根据检测结果确定所述第一待判定平面是否为可见面；以及针对下一个待判定平面执行所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面。

Description

可见面判定方法、反向射线追踪方法及装置 技术领域
本公开涉及一种通信技术，特别是涉及一种可见面判定方法、反向射线追踪方法及装置。
背景技术
在室内环境中进行定位时，由于室内环境的复杂性远远高于室外环境，且室内定位的精度要求比室外定位更为严格，导致传统的信道模型不再适用，这对定位信号的传播分析提出了更为严峻的挑战。
对此，在室内环境中，可以使用信道模拟对信号进行传播分析。信道模拟可以采用仿真手段来模拟信号传播的真实信道环境，代表性的信道模拟可以基于射线追踪技术。在射线追踪技术中，反向射线追踪算法可以比较精确地计算出每条射线路径中的信道特性。然而，绕射现象的存在使得镜像点的建立存在无限种可能，大量镜像点的建立以及由此导致的大量的相交测试增加了计算的复杂度并且降低了判断效率。
发明内容
一方面，本公开提供一种可见面判定方法，包括步骤：获取目标空间中的待判定平面的平面信息；针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；根据检测结果确定所述第一待判定平面是否为可见面；以及针对下一个待判定平面执行所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面。
另一方面，本公开还提供一种反向射线追踪方法，所述方法包括步骤：获取目标空间中的待判定平面的平面信息；针对第一待判定 平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；根据检测结果确定所述第一待判定平面是否为可见面；针对下一个待判定平面执行所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面，以获取目标空间中的可见面的集合，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面；以及根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算，以确定相应的信号传播路径。
另一方面，本公开还提供一种可见面判定装置，包括：获取单元，其设置为获取目标空间中的待判定平面的平面信息；检测单元，其设置为针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；以及确定单元，其设置为根据检测结果确定所述第一待判定平面是否为可见面，其中，所述检测单元和所述确定单元还设置为针对下一个待判定平面执行所述检测操作和所述确定操作，直至遍历了所有的所述待判定平面，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面。
另一方面，本公开还提供一种反向射线追踪装置，包括如上所述的可见面判定装置，并且还包括：获取单元，通信地耦合到所述可见面判定装置，并且其设置为获取目标空间中的可见面的集合；传播计算单元，其设置为根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算以确定相应的信号传播路径。
另一方面，本公开还提供一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时，使得所述处理器执行根据本公开的可见面判定方法或者反向射线追踪方法。
附图说明
图1是根据本公开实施例的可见面判定方法的步骤流程图；
图2是根据本公开实施例的可见面判定方法的实施流程图；
图3是根据本公开实施例的反向射线追踪方法的步骤流程图；
图4是根据本公开实施例的反向射线追踪方法的实施流程图；
图5是在定位场景1中的可见面判定示意图；
图6是定位场景1的空间布局图；
图7是在定位场景2中的可见面判定示意图；
图8是定位场景2的空间布局图；
图9是在定位场景3中的可见面判定示意图；
图10是定位场景3的空间布局图；
图11是根据本公开实施例的可见面判定装置的结构示意图；以及
图12是根据本公开实施例的反向射线追踪装置的结构示意图。
具体实施方式
在室内环境中，可以使用信道模拟对信号进行传播分析。信道模拟可以采用仿真手段来模拟信号传播的真实信道环境。代表性的信道模拟可以基于射线追踪技术。在射线追踪技术中，反向射线追踪算法可以比较精确地计算出每条射线路径中的信道特性。然而，绕射现象的存在使得镜像点的建立存在无限种可能。大量镜像点的建立以及由此导致的大量的相交测试增加了计算射线追踪传播路径的开销并且降低了判断效率。
在一些情形中，可以采用投影相交判定的方法来判断环境中的哪些平面是不可见(被遮挡)的从而在该平面处不会发生反射、折射、绕射，以减少需要建立的镜像点的数量、并节省计算射线追踪传播路径的开销。但在这种情形中，需要针对环境中的每个物体计算三次投影(向X轴、Y轴、Z轴三个方向分别投影)以获得其三个投影面(在XY平面、XZ平面、YZ平面上的投影面)，并且针对所述物体的每个 面，利用所述物体的三个投影面进行多次判断以确定所述面是否是可见面。这在降低射线追踪传播路径开销的同时又引入了新的计算代价，开销较大。
以下结合附图对本公开的各实施例进行详细说明。应当理解，此处所描述的具体实施例仅用于通过示例的方式来解释本公开，并不旨在限定本公开的范围。
图1是根据本公开实施例的可见面判定方法的步骤流程图。
如图1所示，本公开实施例提供一种可见面判定方法，其包括步骤S11-S14。
在步骤S11处，获取目标空间中的待判定平面的平面信息。
在步骤S12处，针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面。
在步骤S13处，根据检测结果确定所述第一待判定平面是否为可见面。
在步骤S14处，针对下一个待判定平面执行所述检测步骤S12和所述确定步骤S13，直至遍历了所有的所述待判定平面。
如上所述，根据本公开的实施例的可见面判定方法，能够避免在投影相交判定中针对每个物体计算三次投影以获得其三个投影面(在XY平面、XZ平面、YZ平面上的投影面)，并且避免了针对所述物体的每个面，利用所述物体的三个投影面进行多次判断以确定所述面是否是可见面的情况，因此在保证计算精度的同时大大减小了计算射线追踪传播路径的开销。
在一个实施例中，所述待判定平面包括所述目标空间中物体的各表面所在的平面，其中，三个待判定平面相交于一个平面凸点。
在一个实施例中，在上述步骤S11中还可以获取发射点的位置信息。
在一个实施例中，在上述步骤S11处，可以针对待定位空间建 立三维可视化的的空间模型。待定位空间也称为目标空间，所述目标空间中布置有一些物体，这些物体的表面可以对传播中的信号进行反射、折射、绕射等等，从而以各种方式影响信号的传播路径。这些物体的表面构成所述待判定平面，所述待判定平面中的每一个与其他任意两个待判定平面的交点构成平面凸点。在根据反向射线追踪进行信道模拟时，网元节点(即发射点)的坐标和平面凸点的坐标为已知条件，可以直接获取。在这种情况下，可以通过可见面判定来消除大量的不可见面，以减轻后续射线传播路径遍历面的计算强度。可见面是指从接收点出发的反向射线能够通过这个面进行反射、折射或者绕射达到发射点的平面。不可见面是指所有的待判定平面中除可见面以外的其它平面。
在一个实施例中，在步骤S12处，针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面的步骤可以包括：读入所述第一待判定平面的平面方程并获得所述第一待判定平面中的各平面凸点的坐标；将所述各平面凸点分别与所述信号发射点连线以获得分别对应于所述各平面凸点的线段；以及检测所述待判定平面中是否存在与所述各条线段都相交的所述第二待判定平面。
在一个实施例中，在步骤S12处描述的所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面，换句话说，所述第一待判定平面是所述待判定平面中的一个平面，而所述第二待判定平面是所述待判定平面中的、不同于所述第一待判定平面的任意一个其他平面。
在一个实施例中，在步骤S13处，根据检测结果确定每个所述待判定平面是否为可见面的步骤可以包括：在所述检测结果为存在所述第二待判定平面的情况下，确定所述第一待判定平面为不可见面；以及在所述检测结果为不存在所述第二待判定平面的情况下，确定所述第一待判定平面为可见面。
在一个实施例中，在步骤S14处，针对下一个待判定平面执行 所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面。也就是说，在步骤S14处遍历目标空间中的所有待判定平面，以判定每个待判定平面是否为可见面，从而获得该目标空间中的所有可见面的集合。
综上，在信号发射点与第一待判定平面之间，如果存在其他待判定平面满足上述相交条件，则该第一待判定平面被其他待判定平面中的某一个或者某几个遮挡，即，该第一待判定平面不可见，因而从信号发射点发射的信号不会经过该第一待判定平面。通过这样的方法对目标空间中所有待判定平面进行判定，可以在进行反向射线追踪的计算时排除针对不可见平面的计算，从而有效为反向射线追踪的计算减小了计算量。
下面通过具体实施例对本公开提供的可见面判定方法进行详细说明。
图2是根据本公开实施例的可见面判定方法的实施流程图。
如图2所示，在一个实施例中，一种对目标空间(例如，室内场景)中的待判定平面是否为可见面判定方法可以包括如下步骤S201-S210。
在步骤S201处，获取目标空间中的待判定平面的平面信息和发射点T的位置信息。所述发射点T的位置信息包括所述发射点T的位置坐标。
在步骤S202处，判断目标空间中的所有待判定平面是否都被遍历，若都被遍历，则转到步骤S210，否则转到步骤S203。
在步骤S203处，读入一个待判定平面的平面方程，并获得处于这个待判定平面中的各凸点的坐标。可以将所读入的一个待判定平面称为第一待判定平面。
在步骤S204处，将待判定平面中的各个凸点分别与发射点T进行连线，以得到分别对应于所述待判定平面中的各个凸点的n条线段，n为所述待判定平面中的凸点的数量。
在步骤S205处，获得在步骤S204中得到的n条线段中的每条 线段的直线方程以及方程变量的取值范围。
在步骤S206处，用步骤S205中获得的n条线段的直线方程与目标空间中的除所述第一待判定平面之外的每一个待判定平面进行相交测试。
在步骤S207处，若存在任意一个被测试的待判定平面使得与这n条线段的直线方程都相交，且交点的坐标取值范围在前述线段的变量的取值范围内，则说明在步骤S203中读入的所述第一待判定平面是不可见的，转到步骤S208；否则，则说明所述第一待判定平面是可见的，转到步骤S209。
在步骤S208处，将所述第一待判定平面标记为伪(false)，转到步骤S202。
在步骤S209处，将第一待判定平面标记为真(true)，转到步骤S202。
在步骤S210处，获得目标空间中的所有可见面的集合。
上述实施例提供的可见面判定方法可以极大地减少需要进行传播分析的平面，从而加速进行射线追踪的速度并减小计算开销。
图3是根据本公开实施例的反向射线追踪方法的步骤流程图。
如图3所示，本公开的实施例还提供一种反向射线追踪方法，所述方法使用根据本公开实施例的可见面判定方法，即，该方法包括图1示出的步骤S11-S14以及S31-S32。
在执行步骤S31之前，执行步骤S11-S14以获取目标空间中的可见面的集合。步骤S11-S14已参照图1进行了详细描述，因而在此处不重复描述。
在步骤S31处，获取目标空间中的可见面的集合。
在步骤S32处，根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算以确定相应的信号传播路径。
本公开的实施例提供的反向射线追踪方法能够获取目标空间中的可见面的集合，以预先排除目标空间中的大量的不可见面，然后根据信号发射点的位置和信号接收点的位置，对每个可见面进行射线传 播计算，从而可以确定信号发射点和信号接收点之间的信号传播路径。
由于反向射线追踪的目的是建立室内信道模型，因此，可以将发射点的位置和接收点的位置作为已知条件来研究信号在每对信号发射点和信号接收点之间的传播路径。另外，根据光路可逆原理可知，信号发射点和信号接收点的位置可以互换而信道仍然存在，此时，信号传输方向相反。
不仅如此，为了确定根据反射、折射、绕射等方式找到的信道是否可以用来进行正常通信，在本公开的一个实施例中，还可以获知定位网元(如基站等)的定位信号的信号强度、发射功率、信号频率等信号参数特性，从而根据这些信号参数特性量化该目标空间中的信号。
在本公开的一个实施例中，在根据信号发射点的位置和信号接收点的位置，对每个可见面进行射线传播计算(步骤S32)之后，本公开实施例提供的反向射线追踪方法还可以包括：确定所述信号传播路径对传输的信号的信号强度的损耗；以及在所述信号的经历了所述损耗后的信号强度大于或等于预设阈值的情况下，保留所述信号传播路径，并且在所述信号的经历了所述损耗后的信号强度小于所述预设阈值的情况下，删除所述信号传播路径。
也就是说，从信号发射点发出的信号在经过目标空间中的物体反射、折射、绕射、吸收后，信号强度会有不同程度的衰减。如果信号经过衰减后到达信号接收点时其信号强度仍然比较大，导致其可以被接收机有效探测到，则对应的信道可以作为一条信号传输路径被保留。否则，如果信号经过衰减后到达信号接收点时其信号强度比较小，导致其无法被接收机有效探测到，则对应的信道已经无法利用，需要将其删除。
本公开实施例提供的反向射线追踪算方法能够有效的模拟信号在空间中的传播路径，建立信道模型，并根据电磁学理论对每一条路径的参数进行计算，从而实现信道的精准模拟。而且，基于可见面判定可以极大地减少需要进行传播分析的平面，从而加速进行射线追踪 的速度并减小计算开销。
图4是根据本公开实施例的反向射线追踪方法的实施流程图。
如图4所示，本实施例提供的反向射线追踪方法可以包括如下步骤S401-S412。
在步骤S401处，建立三维坐标系，将待定位的目标空间中的物体的表面分解为一系列的面，将其中每一个面表示为surface i＝(Eqi,domain)，其中Eqi是面方程，domain是所述面方程的变量的取值范围。假定目标空间中共存在N个待确定平面，将所述N个待确定平面记为集合U＝{surface i,1<i<N}，其中，N是大于零的正整数，i是在1和N之间的正整数变量。
在步骤S402处，获取网元的位置信息，即，得到网元的发射点的三维位置坐标。
在步骤S403处，获取网元的定位信号的信号强度、发射功率、信号频率等信号参数特性。
在步骤S404处，获取终端的位置信息，即，得到接收点的三维位置坐标。
在步骤S405处，通过上述实施例提供的可见平面判定方法(即，图1所示的步骤S11-S14)来获得所有可见面的集合V。假定目标空间中共存在M个可见面，将所述可见面的集合记为V＝{surface i,1<i<M}，其中，M是大于零的正整数，i是在1和M之间的正整数变量，并设置i＝1。可见面的集合V是上述待判定集合U的子集，因而M≤N。
在步骤S406处，从可见面的集合V取出可见面surface i，依次采用反射、折射和绕射方式，针对可见面surface i进行射线传播计算，并根据设定的反射、折射和绕射次数，得到针对所述可见面的射线传播路径，将其存入终端(即，接收点)的射线路径表。
在步骤S407处，根据所述信号传播路径和现有的直射、反射、折射和绕射损耗计算公式，确定信号在沿所述射线传播路径的传播过程中的损耗参数。
在步骤S408处，通过将经历了所述损耗的信号的信号强度与预 设的信号强度最小值(即，阈值)进行比较，判断所述信号强度是否满足信号强度约束条件，即，信号强度是否大于或等于预设阈值。若判断结果为“是”，说明满足约束条件，转到步骤S409。若判断结果为“否”，说明不满足约束条件，转到步骤S410。
在步骤S409处，满足约束条件，即信号强度大于或等于预设阈值，这表明信号强度仍可用于定位，则保存当前信号传播路径与信号强度及其损耗以待后续计算使用。转到步骤S411。
在步骤S410处，不满足约束条件，即信号强度小于预设阈值，这表明该信号已无法用于定位，则结束该路径搜索并删除相应的信号传播路径。转到步骤S411。
在步骤S411处，令i加1，即i＝i+1，并转到步骤S412。
在步骤S412处，判断是否i≤M。如果是，则转到步骤S406，继续针对下一个可见面分析射线传播路径；如果否，则已经针对所有的可见面分析了射线传播路径，结束流程。
下面通过具体实施例对本公开提供的反向射线追踪方法进行详细说明。
图5是在定位场景1中的可见面判定示意图。
在定位场景1中，如图5所示，图中T为发射点，平面ABCD为一个待判定平面。下面为采用例如参照图1和图2描述的可见面判定方法，针对定位场景1中的一个待判定平面进行判断的示例。出于简洁的目的，此处仅描述涉及所述待判定平面ABCD的具体步骤，并省略了其他步骤。
所述判定方法可以包括：读入一个待判定的空间平面ABCD的平面方程，并获得其中各凸点A、B、C、D的坐标；将待判定的空间平面ABCD的各个凸点A、B、C、D分别与发射点T进行连线，得到4条线段；获得每条线段TA、TB、TC、TD的直线方程，以及方程变量的取值范围；用得到的4条线段的直线方程与目标空间模型中的除了所述平面ABCD之外的每一个面进行相交测试；在本实施例中，如图5所示，存在一平面A'B'C'D'，其与线段TA、TB、TC、TD都相交，且相交点的坐标取值在前述线段的方程变量的取值范围内，这说明待 判定平面ABCD是不可见面，从而将空间平面ABCD标记为伪(false)。
在本实施例中，确定了空间平面ABCD为不可见平面，并且假定遮挡空间平面ABCD的空间平面A'B'C'D'为可见面。
下面为采用例如参照图3和图4描述的反向射线追踪方法，针对定位场景1中的一个待判定平面进行射线传播计算以确定相应的信号传播路径的示例。出于简洁的目的，此处仅通过示例的方式来描述特定于平面A'B'C'D'的步骤，并省略了其他步骤。
图6是定位场景1的空间布局图。
如图6所示，针对可见面的集合中的一个可见面A'B'C'D'，采用反射方式进行射线传播计算。例如，通过一次反射得到信号的传播路径。首先对于物体2，发射点T根据面A'B'C'D'创建镜像点Mr，此镜像点Mr与接收点R之间存在可以直接到达的路径Mr→R，该路径与可见面A'B'C'D'的交点为O，从而获得从发射点T到接收点R的信号传播路径为T→O→R。将此路径存入终端(即，接收点R)的射线路径表。
此后针对该路径T→O→R执行参照图3描述的步骤，其具体实现类似于参照图4描述的步骤S407-S410，此处不再赘述。
图7是在定位场景2中的可见面判定示意图。
在定位场景2中，如图7所示，图中T为发射点，平面HIJK为一个待判定平面。下面为采用例如参照图1和图2描述的可见面判定方法，针对定位场景2中的一个待判定平面进行判断的示例。出于简洁的目的，此处仅描述涉及所述待判定平面HIJK的具体步骤，并省略了其他步骤。
所述判定方法可以包括：读入一个待判定的空间平面HIJK的平面方程，并获得其中各凸点H、I、J、K的坐标；将待判定的空间平面HIJK的各个凸点H、I、J、K分别与发射点T进行连线，得到4条线段；获得每条线段TH、TI、TJ、TK的直线方程，以及方程变量的取值范围；用得到的4条线段的直线方程与目标空间中的除了所述平面HIJK之外的每一个面进行相交测试；如图7所示，不存在任意一个被测试的平面与这4条线段TH、TI、TJ、TK都相交，这说明待 判定的空间平面HIJK为可见面，从而将空间平面HIJK标记为真(true)。
在本实施例中，确定了空间平面HIJK为可见面，此处还假定空间平面MNN'M'也是可见面。
下面为采用例如参照图3和图4描述的反向射线追踪方法，针对定位场景2中的一个待判定平面进行射线传播计算以确定相应的信号传播路径的示例。出于简洁的目的，此处仅通过示例的方式来描述特定于平面MNN'M'的具体步骤，并省略了其他步骤。
图8是定位场景2的空间布局图。
如图8所示，针对可见面MNN'M'进行射线传播计算，例如，通过两次反射得到信号在室内环境下的传播路径。首先对于物体3，发射点T根据可见面MNN'M'创建镜像点Mr1。通过相交测试发现，镜像点Mr1与接收点R之间有物体2遮挡，因而不存在可直接到达的路径。再根据物体1的HIJK面创建镜像点Mr1的二次镜像点Mr2，此时发现二次镜像点Mr2与R之间存在可直接到达的路径Mr2→R，Mr2和R的连线与平面的HIJK之间的交点为O，交点O和镜像点Mr1的连线与平面MNN'M'之间的交点为O'，从而获得从发射点T到接收点R的信号传播路径为T→O'→O→R。将此路径存入终端(即，接收点R)的射线路径表。
此后针对该路径T→O'→O→R执行参照图3描述的步骤，其具体实现类似于参照图4描述的步骤S407-S410，此处不再赘述。
图9是在定位场景3中的可见面判定示意图。
在定位场景3中，如图9所示，图中T为发射点，平面SXUV为待判定平面。下面为采用例如参照图1和图2描述的可见面判定方法，针对定位场景3中的一个待判定平面进行判断的示例。出于简洁的目的，此处仅描述涉及所述待判定平面SXUV的具体步骤，并省略了其他步骤。
所述判定方法可以包括：读入一个待判定的空间平面SXUV的平面方程，并获得其中各凸点S、X、U、V的坐标；将待判定的空间平面SXUV的各个凸点S、X、U、V分别与发射点T进行连线，得到4 条线段；获得得到的每条线段TS、TX、TU、TV的直线方程，以及方程变量的取值范围；用得到的4条线段的直线方程与目标空间中的除了所述平面SXUV之外的每一个面进行相交测试；如图9所示，存在一个平面S'X'U'V'，与线段TS、TX相交但与线段TU、TV不相交，且不存在任意一个平面与这4条线段TS、TX、TU、TV都相交，这说明待判定的空间平面SXUV是可见面，从而将空间平面SXUV标记为真(true)。
在本实施例中，确定了空间平面SXUV为可见面，此处还假定空间平面QZZ'Q'和空间平面S'X'U'V'也是可见面。
下面为采用例如参照图3和图4描述的反向射线追踪方法，针对定位场景3中的一个待判定平面进行射线传播计算以确定相应的信号传播路径的示例。出于简洁的目的，此处仅通过示例的方式来描述特定于平面QZZ'Q'的具体步骤，并省略了其他步骤.
图10是定位场景3的空间布局图。
如图10所示，针对如可见面QZZ'Q'，采用反射方式进行射线传播计算，例如，通过两次反射得到信号在室内环境下的传播路径。首先对于物体2，发射点T根据可见平面QZZ'Q'创建镜像点Mr1，并通过相交测试发现，镜像点Mr1与R之间有物体2遮挡，不存在可直接到达的路径。再根据物体1的可见平面S'X'U'V'创建镜像点Mr1的二次镜像点Mr2，此时发现二次镜像点Mr2与R之间存在可直接到达的路径Mr2→R，Mr2和R的连线与平面S'X'U'V'之间的交点为O'，交点O'和镜像点Mr1的连线与平面QZZ'Q'之间的交点为O，从而获得从发射点T到接收点R的信号传播路径T→O→O'→R。将此路径存入终端(即，接收点R)的射线路径表。
此后针对该路径T→O→O'→R执行参照图3描述的步骤，其具体实现类似于参照图4描述的步骤S407-S410，此处不再赘述。
本公开的实施例提供了一种反向射线追踪方法，在一方面，所述反向射线追踪算法将二维射线追踪转化为三维射线追踪，进一步提高了信号传播分析结果的精度。在另一方面，其使用轻量级的基于相交测试的可见面判定算法，提高了使用反向射线追踪算法来模拟计算 信号传播路径的运行速度、大大降低了运行时间、并提高了分析效率。
图11是根据本公开实施例的可见面判定装置的结构示意图。
如图11所示，本公开的实施例还提供一种可见面判定装置，所述装置设置在计算机设备中，并包括获取单元111、检测单元112和确定单元113。
获取单元111设置为获取目标空间中的待判定平面的平面信息。
检测单元112设置为针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面。
确定单元113设置为根据检测结果确定所述第一待判定平面是否为可见面。
检测单元112和确定单元113还设置为针对下一个待判定平面执行所述检测操作和所述确定操作，直至遍历了所有的所述待判定平面。
在一个实施例中，所述待判定平面包括所述目标空间中物体的各表面所在的平面，其中，三个所述待判定平面相交于一个平面凸点。
在一个实施例中，获取单元还111设置为获取发射点的位置信息。
在一个实施例中，检测单元112还设置为：读入所述第一待判定平面的平面方程并获得所述第一待判定平面中的各平面凸点的坐标；将所述各平面凸点分别与所述信号发射点连线以获得分别对应于所述各平面凸点的线段；以及检测所述待判定平面中是否存在与所述各条线段都相交的第二待判定平面。
在一个实施例中，确定单元113还设置为：在所述检测结果为存在所述第二待判定平面的情况下，确定所述第一待判定平面为不可见面；以及在所述检测结果为不存在所述第二待判定平面的情况下，确定所述第一待判定平面为可见面。
如上所述，根据本公开的实施例的可见面判定装置，能够避免 在投影相交判定中针对每个物体计算三次投影以获得其三个投影面(在XY平面、XZ平面、YZ平面上的投影面)，并且避免了针对所述物体的每个面，利用所述物体的三个投影面进行多次判断以确定所述面是否是可见面的情况，因此在保证计算精度的同时大大减小了计算射线追踪传播路径的开销。
图12是根据本公开实施例的反向射线追踪装置的结构示意图。
如图12所示，本公开的实施例还提供一种反向射线追踪装置，所述装置设置在计算机设备中，包括如上所述的可见面判定装置，并且还包括第二获取单元121和传播计算单元122。
第二获取单元121通信地耦合到所述可见面判定装置并且设置为获取目标空间中的可见面的集合。
传播计算单元122设置为根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算以确定相应的信号传播路径。
在一个实施例中，获取单元121还设置为获取发射点的位置信息和接收点的位置信息。
在一个实施例中，所述反向射线追踪装置还可包括损耗确定单元、保留单元和删除单元。
损耗确定单元设置为确定由传播计算单元122确定的所述信号传播路径对传输的信号的信号强度的损耗。
保留单元设置为在所述信号的经历所述损耗后的信号的信号强度大于或等于预设阈值的情况下，保留所述信号传播路径。
删除单元设置为在所述信号的经历所述损耗后的信号的信号强度小于所述预设阈值的情况下，删除所述信号传播路径。
需要说明的是，在本文中，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者装置不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括这种过程、方法、物品或者装置所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括该要素的过程、方法、物品或者装置中还存在 另外的相同要素。
通过以上的实施方式的描述，本领域的技术人员可以清楚地了解到上述实施例方法可借助软件以及必需的通用硬件平台的组合的方式来实现。当然，也可以通过硬件来实现。基于这样的理解，本公开的技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质(如ROM/RAM、磁碟、光盘)中，并包括若干指令以使得一台终端设备(可以是手机、计算机、服务器、空调器、或者网络设备等)执行本公开各个实施例所述的方法。
尽管出于示例目的，已经具体公开了本公开的一些实施例，但本领域的技术人员将意识到各种改进、增加和取代也是可能的。因此，本公开的范围应当不限于上述实施例。

Claims (18)

  1. 一种可见面判定方法，包括步骤：
    获取目标空间中的待判定平面的平面信息；
    针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；
    根据检测结果确定所述第一待判定平面是否为可见面；以及
    针对下一个待判定平面执行所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面。
  2. 根据权利要求1所述的方法，其中，所述待判定平面包括所述目标空间中物体的各表面所在的平面，其中，所述待判定平面中的三个待判定平面相交于一个平面凸点。
  3. 根据权利要求1所述的方法，在针对第一待判定平面来检测是否存在一个第二待判定平面的步骤之前，所述方法还包括步骤：
    获取发射点的位置信息。
  4. 根据权利要求1或2所述的方法，其中，针对第一待判定平面来检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面的步骤包括：
    读入所述第一待判定平面的平面方程并获得所述第一待判定平面中的各平面凸点的坐标；
    将所述各平面凸点分别与所述信号发射点连线以获得分别对应于所述各平面凸点的线段；以及
    检测所述待判定平面中是否存在与所述各条线段都相交的所述 第二待判定平面。
  5. 根据权利要求1或2所述的方法，其中，根据检测结果确定所述第一待判定平面是否为可见面的步骤包括：
    在所述检测结果为存在所述第二待判定平面的情况下，确定所述第一待判定平面为不可见面；以及
    在所述检测结果为不存在所述第二待判定平面的情况下，确定所述第一待判定平面为可见面。
  6. 一种反向射线追踪方法，包括步骤：
    获取目标空间中的待判定平面的平面信息；
    针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；
    根据检测结果确定所述第一待判定平面是否为可见面；
    针对下一个待判定平面执行所述检测步骤和所述确定步骤，直至遍历了所有的所述待判定平面，以获取目标空间中的可见面的集合，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面；以及
    根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算，以确定相应的信号传播路径。
  7. 根据权利要求6所述的方法，还包括步骤：
    获取发射点的位置信息和接收点的位置信息。
  8. 根据权利要求6所述的方法，其中，在根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算的步骤之后，所述方法还包括步骤：
    确定所述信号传播路径对传输的信号的信号强度的损耗；以及
    在所述信号的经历了所述损耗后的信号强度大于或等于预设阈值的情况下，保留所述信号传播路径，并且在所述信号的经历了所述损耗后的信号强度小于所述预设阈值的情况下，删除所述信号传播路径。
  9. 一种可见面判定装置，包括：
    获取单元，其设置为获取目标空间中的待判定平面的平面信息；
    检测单元，其设置为针对第一待判定平面，检测是否存在一个第二待判定平面使得所述第一待判定平面中的各平面凸点与信号发射点所连形成的各条线段都穿过所述第二待判定平面，其中，所述第一待判定平面、所述第二待判定平面为所述待判定平面中的任意两个平面；以及
    确定单元，其设置为根据检测结果确定所述第一待判定平面是否为可见面，
    其中，所述检测单元和所述确定单元还设置为针对下一个待判定平面执行所述检测操作和所述确定操作，直至遍历了所有的所述待判定平面，其中，所述下一个待判定平面为所述待判定平面中未经判定的平面中的一个平面。
  10. 根据权利要求9所述的可见面判定装置，其中，所述待判定平面包括所述目标空间中物体的各表面所在的平面，其中，所述待判定平面中的三个待判定平面相交于一个平面凸点。
  11. 根据权利要求9所述的可见面判定装置，其中，所述获取单元还设置为获取发射点的位置信息。
  12. 根据权利要求9或10所述的可见面判定装置，其中，所述检测单元还设置为：
    读入所述第一待判定平面的平面方程并获得所述第一待判定平面中的各平面凸点的坐标；
    将所述各平面凸点分别与所述信号发射点连线以获得分别对应于所述各平面凸点的线段；以及
    检测所述待判定平面中是否存在与所述各条线段都相交的所述第二待判定平面。
  13. 根据权利要求9或10所述的可见面判定装置，其中，所述确定单元还设置为：
    在所述检测结果为存在所述第二待判定平面的情况下，确定所述第一待判定平面为不可见面；以及
    在所述检测结果为不存在所述第二待判定平面的情况下，确定所述第一待判定平面为可见面。
  14. 一种反向射线追踪装置，包括根据权利要求9所述的可见面判定装置，并且还包括：
    第二获取单元，其通信地耦合到所述可见面判定装置，并且设置为获取目标空间中的可见面的集合；以及
    传播计算单元，其设置为根据信号发射点的位置和信号接收点的位置，对所述集合中的每个可见面进行射线传播计算，以确定相应的信号传播路径。
  15. 根据权利要求14所述的反向射线追踪装置，其中，所述第二获取单元还设置为获取发射点的位置信息和接收点的位置信息。
  16. 根据权利要求14所述的反向射线追踪装置，还包括：
    损耗确定单元，其设置为确定由所述传播计算单元确定的所述信号传播路径对传输的信号的信号强度的损耗；
    保留单元，其设置为在所述信号的经历了所述损耗后的信号强度大于或等于预设阈值的情况下，保留所述信号传播路径；以及
    删除单元，其设置为在所述信号的经历了所述损耗后的信号强度小于所述预设阈值的情况下，删除所述信号传播路径。
  17. 一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时，使得所述处理器执行根据权利要求1至5中任一项所述的可见面判定方法。
  18. 一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时，使得所述处理器执行根据权利要6至8中任一项所述的反向射线追踪方法。
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