Tunnel full-route laser radar effective detection distance calculation method and device and medium

Abstract

The invention relates to a tunnel full-route laser radar effective detection distance calculation method and device and a medium, and the method comprises the steps: carrying out the tunnel modeling according to a fixed measurement drawing after the construction of a track, and calculating the effective detection distance of a radar at each point on the track according to an established tunnel model, the center of an object in a tunnel section at a first set distance from the point is an end point, calculating an included angle between a connecting line of all tunnel points and the starting point and a connecting line of the starting point and the end point from the starting point to the end point, if the included angle is smaller than the resolution of the radar, setting a point where the end point retracts towards the starting point by a set mileage as a new end point, and then repeating the calculation process; from the starting point to the ending point, the included angle between the connecting line of all the tunnel points and the starting point and the connecting line of the starting point and the ending point is greater than the resolution of the radar, and the distance from the ending point to the starting point is the effective detection distance at the starting point. Compared with the prior art, the method has the advantages of high calculation precision and the like.

Description

Technical Field

[0001] The present invention relates to a rail transit signal system, and in particular to a method, device and medium for calculating the effective detection distance of a laser radar along the entire route of a tunnel. Background Art

[0002] With the continuous development of rail transit autonomous driving technology, the use of laser radar for forward active detection of trains has gradually become a powerful means to ensure driving safety. Tunnels are very common scenes in rail transit. Due to the obstruction of the radar field of view by the physical structure and installation facilities of the tunnel, the effective detection range of the laser radar changes continuously as the train moves. This change will lead to sudden changes and instability in the detection results, which is very unfavorable to the effectiveness of laser radar-based train safety protection. Therefore, it is very necessary to determine the effective detection range of the current radar at each position in the tunnel. In addition, different radars have different detection performances, and different installation positions have different detection performances. The structural characteristics of the detected objects and the obstruction of the tunnel structure also cause different detection distances. Therefore, it is very valuable to be able to infer the effective detection range of the radar based on the radar characteristics, installation position, tunnel structure, and structural characteristics of the object to be inspected, and to limit the output of the radar detection results accordingly to ensure the effectiveness and safety of the output results.

[0003] After searching, the current research on tunnel modeling includes: reading and modeling using two-dimensional CAD drawings of tunnel construction drawings (such as patent CN117934751A), considering three-dimensional modeling of tunnel walls and internal pipelines (such as patent CN114399600B), etc.; the calculation of tunnel visual distance includes: estimating calculation on a two-dimensional plane (such as patent CN117688642A), using a rangefinder for actual detection (such as patent CN117934751A), etc., but there is no method for determining the effective detection distance of the laser radar in the tunnel, and there is no method that can automatically calculate the effective detection distance of the entire radar by comprehensively considering the radar installation position, the actual detection performance of the laser radar, the obstruction of the actual structure in the tunnel, etc. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method, device and medium for calculating the effective detection distance of the laser radar along the entire route of a tunnel.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] According to a first aspect of the present invention, a method for calculating the effective detection distance of a laser radar along the entire route of a tunnel is provided. The method models a tunnel according to drawings determined after track construction, and calculates the effective detection distance of the radar at each point on the track according to the established tunnel model, wherein the calculation process includes:

[0007] First, a certain point is set as the starting point, and the center of the object in the tunnel profile at the first set distance from the point is set as the end point. The angle between the starting point and the end point is calculated. If there is an angle smaller than the resolution of the radar, it means that the end point is beyond the effective detection performance of the radar at this location. The point where the end point is retracted toward the starting point by a set mileage is set as the new end point, and then the calculation process is repeated until the angle between the starting point and the end point is greater than the resolution of the radar. At this time, the distance between the end point and the starting point is the effective detection distance at the starting point.

[0008] As a preferred technical solution, the tunnel modeling process specifically includes:

[0009] Step S1, determine the size of the object to be detected, and calculate the maximum straight line detection performance D of the laser radar when detecting the object max ;

[0010] Step S2, sorting the mileage-elevation data and performing elevation calculation;

[0011] Step S3, sorting the mileage-plane data and calculating the horizontal coordinates;

[0012] Step S4, correcting the mileage-plane information data according to the values ​​of the long and short chains;

[0013] Step S5, combining the vertical height and the two-dimensional coordinates of each point on the line to obtain the three-dimensional coordinates of each point;

[0014] Step S6, performing tunnel profile modeling;

[0015] Step S7, constructing the overall tunnel model.

[0016] As a preferred technical solution, in step S1, the maximum straight line detection performance D max It is equal to the minimum value of the maximum detection distance calculated by horizontal resolution, the maximum detection distance calculated by vertical resolution, and the nominal longest straight line detection distance.

[0017] As a preferred technical solution, the D max The specific calculation is as follows:

[0018]

[0019] Where L O , W O D is the length and width of the object facing the radar. m is the farthest straight-line detection distance of the laser radar, are the horizontal and vertical resolutions of the LiDAR.

[0020] As a preferred technical solution, in step S2, the track construction drawings are organized into a data table, and the longitudinal section drawings are organized into mileage-elevation information data, thereby calculating the vertical height of each point on the route along the mileage.

[0021] As a preferred technical solution, the mileage-elevation information data includes the starting mileage value of each straight ramp, the ending mileage value of the straight ramp, the ending mileage value of the variable ramp, the slope of the straight ramp, the curvature radius of the variable ramp and the direction of the slope change.

[0022] As a preferred technical solution, in step S3, the track construction plan is organized into mileage-plane information data, thereby calculating the two-dimensional coordinates of each point on the route along the mileage.

[0023] As a preferred technical solution, the mileage-plane information data includes the starting mileage value of each straight line segment, the ending mileage value of the straight line segment, the ending mileage value of the curve, the curvature radius of the curve, the curve rotation angle, the length of the gentle circle segment, the length of the gentle circle segment and the curve rotation direction.

[0024] As a preferred technical solution, in step S4, if there is a long chain of k meters at mileage A, the mileage information after mileage A in all mileage-elevation information is increased by k meters, and the corresponding elevation value is recalculated; at the same time, the mileage information after mileage A in all mileage-plane information is increased by k meters, and the plane two-dimensional coordinates are recalculated.

[0025] As a preferred technical solution, in step S6, the tunnel profile modeling is specifically as follows:

[0026] According to the tunnel profile of the modeled tunnel, the relative position relationship between the tunnel center, the two tracks, the train center, and the radar installation position is determined. The tunnel profile is discretely taken at every set angle, and the position point of the radar at that location and the center point of the detected object are added to form a tunnel profile model.

[0027] As a preferred technical solution, in step S7, the discrete points of the tunnel profile are aggregated at every second set distance along the mileage to form a point set, which is the overall model of the tunnel.

[0028] As a preferred technical solution, the second set distance is 1m.

[0029] As a preferred technical solution, the first set distance is the maximum straight line detection performance D max .

[0030] According to a second aspect of the present invention, there is provided an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the method described above is implemented when the processor executes the program.

[0031] According to a third aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the program implements the method described above when executed by a processor.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1) The present invention aims at the problem that it is difficult to measure the effective detection distance of the radar under different performances of laser radars, different installation positions, and changing tunnel structures. By mathematically modeling the track construction drawings of the tunnel structure, the tunnel profile, the relative positions of the radar, the train, and the track, and the linear detection performance of the radar, and taking into account the detection performance of the radar, the installation position of the radar, the structural characteristics of the detected object, and the field of view obstruction caused by the installation of facilities in the tunnel, the calculated maximum visual distance is closer to the actual detection of the radar;

[0034] 2) The present invention uses the calculated maximum visual distance to limit the safe detection range of the detection system, making the output radar detection data safer and more reliable;

[0035] 3) The present invention is based on tunnel mapping modeling, taking into account the transition curve and the length of the chain, and the model has high accuracy, with the error with the drawing being on the order of 10^-7. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of the calculation of the safe detection distance of the laser radar along the entire line based on the tunnel construction map of the present invention;

[0037] Figure 2 A side view of an object detected by the vehicle-mounted laser radar of the present invention

[0038] Figure 3 A top view of an object detected by the vehicle-mounted laser radar of the present invention

[0039] Figure 4 This is a cross-sectional model diagram of a shield tunnel according to the present invention;

[0040] Figure 5 This is a cross-sectional model diagram of a square tunnel dug in the present invention;

[0041] Figure 6 This is a rendering of the tunnel modeling of the present invention;

[0042] Figure 7 This is a flow chart for calculating the maximum effective detection distance of the present invention;

[0043] Figure 8 This is a schematic diagram of calculating the effective detection distance of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0045] The present invention constructs a track model according to the drawings determined after track construction, takes into account radar characteristics, installation location, actual tunnel structure, and structural characteristics of the object to be inspected, and calculates the effective detection distance of the laser radar along the entire route.

[0046] like Figure 1 As shown, the specific processing steps of the present invention are as follows:

[0047] Step S001: Determine the linear detection performance of the laser radar: According to the length and width (L O , W o ), the longest straight-line detection distance of the laser radar (D m ), the horizontal resolution and vertical resolution of the lidar Calculate the straight line detection performance (D max ) is equal to the minimum value of the maximum detection distance calculated by horizontal resolution, the maximum detection distance calculated by vertical resolution, and the nominal farthest straight line detection distance:

[0048]

[0049] Step S002, elevation calculation: organize the track construction drawings into a data table, and organize the longitudinal section into mileage-slope information data, each of which includes in the vertical direction: the starting mileage value of each straight ramp, the end mileage value of the straight ramp (also the starting point of the variable ramp), the end mileage value of the variable ramp, the slope of the straight ramp (uphill is positive, downhill is negative), the curvature radius of the variable ramp, and the direction of the variable slope (clockwise / counterclockwise). In this way, the vertical height of each point on the route along the mileage (relative to the starting point of the line) is calculated.

[0050] Step S003, horizontal coordinate calculation: by arranging the plane map into mileage-plane information data, each piece of information is included in the plane: the starting mileage value of each straight line segment, the end mileage value of the straight line segment (the starting point of the curve), the end mileage value of the curve, the curvature radius of the curve, the curve rotation angle, the length of the slow circle segment, the length of the slow circle segment, the curve rotation direction (counterclockwise rotation around the Z axis is positive, clockwise rotation is negative). Thus, the plane two-dimensional coordinates of each point on the route along the mileage (relative to the two-dimensional coordinates of the starting point of the route) are calculated.

[0051] Step S004, long and short chain correction: For places where long and short chains exist on the plane drawing, the mileage-plane information data is corrected according to the values ​​of the long and short chains. For example, if there is a long chain of k meters at mileage A, it is necessary to increase the mileage information after mileage A in all mileage-elevation information by k meters, and then recalculate the corresponding elevation value, increase the mileage information after mileage A in all mileage-plane information by k meters, and then recalculate the plane two-dimensional coordinates;

[0052] Step S005, obtaining three-dimensional coordinates: combining the vertical height and the two-dimensional coordinates of each point on the route to obtain the three-dimensional coordinates of each point;

[0053] Step S006, tunnel profile modeling: determine the relative position relationship between the tunnel center, two tracks, train center, and radar installation position according to the tunnel profile of the modeled tunnel, discretely take points at certain angles on the tunnel profile, add the radar position point at that location, and the center point of the detected object, and together form a tunnel profile model;

[0054] Step S007, tunnel modeling: according to the mileage value from the starting point to the end point, the direction vector and three-dimensional coordinates of the track at each mileage value are calculated, and then the tunnel section model perpendicular to the direction vector at that point is calculated. All points constitute the point set model of the tunnel. Here, the section models of different tunnel sections can be defined according to the engineering limit drawings of the tunnel, and the facilities and structures in the tunnel that have a greater impact on the field of view are taken into account, such as the emergency platform, contact network, third rail, etc.;

[0055] Step S008, calculation of effective detection distance: When calculating the effective detection distance of the radar at each point on the track, first set the point as the starting point, and then calculate the maximum detection performance D calculated in step S001. max ) is taken as the end point, and the angles between the lines connecting all tunnel points and the starting point and the lines connecting the start and end points are calculated. If there is an angle smaller than the radar resolution, it means that for the radar at the starting point, the radar field of view of the object at the end point is blocked by the tunnel wall, that is, the end point is beyond the effective detection performance of the radar at the starting point. Then the point at a certain distance from the end point to the starting point is set as the new end point, and step S008 is repeated until the angles between the lines connecting all tunnel points and the starting point and the lines connecting the start and end points are greater than the radar resolution. At this time, the distance between the end point and the starting point is the effective detection distance at the starting point. Specific embodiments

[0057] Figure 1This is a step-by-step diagram of the calculation of the safe detection distance of the entire line of the LiDAR based on the tunnel construction map. First, determine the size of the object to be detected, and calculate the maximum straight-line detection performance of the LiDAR when detecting the object; then organize the mileage-elevation data and perform elevation calculations; organize the mileage-horizontal data and perform horizontal coordinate calculations; merge them into three-dimensional coordinates; correct the errors caused by long and short chains on the line; mathematical modeling of the tunnel profile; mathematical modeling of the typical tunnel structure and tunnel wall; and finally calculate the maximum effective detection range.

[0058] Figure 2 and Figure 3 They are the side view and top view of the object detected by the vehicle-mounted laser radar. If the size of the detected object facing the radar is L o ×W o , the horizontal and vertical resolutions of the lidar are In order to ensure that the object can be detected (the object has at least 2×2 points in the laser point cloud), the laser radar based on the horizontal resolution of the object The laser radar's vertical resolution of the object The nominal detection distance of the laser radar is the value set in its technical manual. m , take the minimum value of the three as the maximum straight-line detection distance of the laser radar to the object.

[0059] Figure 4 and Figure 5 They are tunnel section model diagrams with different structures. Figure 4 It is a shield tunnel. Figure 5 It is an open cut square tunnel; Figure 4 The emergency platform in the tunnel is also considered, so the circular tunnel profile is divided in the lower left corner according to the size of the manual maintenance platform, and the tunnel profile is discretized (discrete into 360 points in the figure), and then the projection points of the radar center and the object center on the plane are added. It should be pointed out here that two tunnel profile models are designed according to the tunnel structure, and they are selected according to the actual tunnel scene. Other types of tunnels can also be modeled and discretized in this way.

[0060] Figure 6 This is a tunnel modeling rendering (a section of it), which is a point set formed by summarizing the discrete points of the tunnel profile every 1m along the mileage, which is the overall tunnel model.

[0061] Figure 7 This is the maximum effective detection distance calculation flow chart. Figure 8 This is a schematic diagram for calculating the effective detection distance. For each point on the entire line, calculate the corresponding maximum effective detection distance of the radar: Determine the point as the starting point S i , the initial end point is set to the starting point Dmax The distance point, let it be E i , take all the tunnel model points between the starting point and the end point as the point set P, and all the points in P form an angle with the starting point and the end point respectively. Calculate each angle and compare it with the angular resolution of the lidar (here the larger value of the horizontal angular resolution and the vertical angular resolution is used). If there is an angle smaller than the angular resolution of the lidar, the end point is outside the maximum effective detection distance, and the end point is adjusted toward the starting point, that is, E i =E i -d (d here is the adjusted mileage value, which is also the resolution of the maximum effective detection distance output, which can generally be set to 1 meter), repeat step S008 until all angles are greater than the radar angle resolution. At this time, E i -S i This is the maximum effective detection distance at this point.

[0062] The above is an introduction to the method embodiment. The following is a further explanation of the scheme of the present invention through electronic equipment and storage medium embodiments.

[0063] The embodiment of the present invention also provides an electronic device including a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or computer program instructions loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The CPU, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0064] Multiple components in the device are connected to the I / O interface, including: input units, such as keyboards, mice, etc.; output units, such as various types of displays, speakers, etc.; storage units, such as disks, optical disks, etc.; and communication units, such as network cards, modems, wireless communication transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunication networks.

[0065] The processing unit performs the various methods and processes described above, such as the method of the present invention. For example, in some embodiments, the method of the present invention can be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program can be loaded and / or installed on the device via a ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the method of the present invention described above can be performed. Alternatively, in other embodiments, the CPU can be configured to perform the method of the present invention by any other appropriate means (e.g., by means of firmware).

[0066] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0067] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0068] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0069] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: This method builds tunnel model according to the drawings determined after track construction, and calculates the effective detection distance of the radar at each point on the track according to the established tunnel model. The calculation process includes: First, a certain point is set as the starting point, and the center of the object in the tunnel profile at the first set distance from the point is set as the end point. The angle between the starting point and the end point is calculated. If there is an angle smaller than the resolution of the radar, it means that the end point is beyond the effective detection performance of the radar at this location. The point where the end point is retracted toward the starting point by a set mileage is set as the new end point, and then the calculation process is repeated until the angle between the starting point and the end point is greater than the resolution of the radar. At this time, the distance between the end point and the starting point is the effective detection distance at the starting point.

2. According to the method for calculating the effective detection distance of the laser radar along the entire tunnel route according to claim 1, it is characterized in that: The tunnel modeling process specifically includes: Step S1, determine the size of the object to be detected, and calculate the maximum straight line detection performance D of the laser radar when detecting the object max ; Step S2, sorting the mileage-elevation data and performing elevation calculation; Step S3, sorting the mileage-plane data and calculating the horizontal coordinates; Step S4, correcting the mileage-plane information data according to the values ​​of the long and short chains; Step S5, combining the vertical height and the two-dimensional coordinates of each point on the line to obtain the three-dimensional coordinates of each point; Step S6, performing tunnel profile modeling; Step S7, constructing the overall tunnel model.

3. According to claim 2, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: In step S1, the maximum straight line detection performance D max It is equal to the minimum value of the maximum detection distance calculated by horizontal resolution, the maximum detection distance calculated by vertical resolution, and the nominal longest straight line detection distance.

4. According to claim 3, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: The D max The specific calculation is as follows: Where L O , W O D is the length and width of the object facing the radar. m is the farthest straight-line detection distance of the laser radar, are the horizontal and vertical resolutions of the LiDAR.

5. According to claim 2, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: In step S2, the track construction drawings are organized into a data table, and the longitudinal section diagram is organized into mileage-elevation information data, thereby calculating the vertical height of each point on the route along the mileage.

6. According to claim 5, a method for calculating the effective detection distance of a laser radar along the entire tunnel route is characterized in that: The mileage-elevation information data includes the starting mileage value of each straight ramp, the ending mileage value of the straight ramp, the ending mileage value of the variable ramp, the slope of the straight ramp, the curvature radius of the variable ramp and the direction of the slope change.

7. According to claim 2, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: In step S3, the track construction plan is organized into mileage-plane information data, thereby calculating the two-dimensional coordinates of each point on the route along the mileage.

8. According to claim 7, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: The mileage-plane information data includes the starting mileage value of each straight line segment, the ending mileage value of the straight line segment, the ending mileage value of the curve, the curvature radius of the curve, the curve rotation angle, the length of the slow circle segment, the length of the slow circle segment and the curve rotation direction.

9. According to claim 2, a method for calculating the effective detection distance of a laser radar along the entire tunnel route, characterized in that: In step S4, if there is a long chain of k meters at mileage A, the mileage information after mileage A in all mileage-elevation information is increased by k meters, and the corresponding elevation value is recalculated; at the same time, the mileage information after mileage A in all mileage-plane information is increased by k meters, and the plane two-dimensional coordinates are recalculated.

10. The method for calculating the effective detection distance of a laser radar along the entire tunnel route according to claim 2, characterized in that: In step S6, the tunnel profile modeling is specifically as follows: According to the tunnel profile of the modeled tunnel, the relative position relationship between the tunnel center, the two tracks, the train center, and the radar installation position is determined. The tunnel profile is discretely taken at every set angle, and the position point of the radar at that location and the center point of the detected object are added to form a tunnel profile model.

11. The method for calculating the effective detection distance of a laser radar along the entire tunnel route according to claim 2, characterized in that: In step S7, the discrete points of the tunnel profile are aggregated at every second set distance along the mileage to form a point set, which is the overall model of the tunnel.

12. The method for calculating the effective detection distance of a laser radar along the entire tunnel route according to claim 11, characterized in that: The second set distance is 1 m.

13. The method for calculating the effective detection distance of a laser radar along the entire tunnel route according to claim 2, characterized in that: The first set distance is the maximum detection performance D of the straight line maa .

14. An electronic device comprising a memory and a processor, wherein a computer program is stored in the memory, wherein: When the processor executes the program, the method according to any one of claims 1 to 13 is implemented.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 13 is implemented.

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