Method and system for calculating radius of curve of semi-closed highway construction section and computer storage medium

Abstract

The embodiment of the invention discloses a semi-closed highway construction section curve radius calculation method and system and a computer storage medium, the semi-closed highway construction section curve radius calculation method comprises the following steps: collecting a latitude and longitude coordinate sequence of a detection section track, the detection section being a semi-closed highway construction section; according to a preset sampling step length, iteratively taking points from the longitude and latitude coordinate sequence so as to construct a triangle and a circumcircle; calculating the radius of the circumcircle to obtain a circumcircle radius set; performing stable section detection on the circumcircle radius set through a sliding window; and carrying out average value calculation on the radius data of the circumcircle in the stable section to obtain the curve radius of the detected road section.

Description

TECHNICAL FIELD

[0001] Embodiments of the present specification relate to the technical field of road highway safety monitoring, and in particular to a method and system for calculating the radius of a curve on a semi-closed highway construction section, and a computer storage medium. BACKGROUND

[0002] With the continuous growth of the number of motor vehicles and new energy vehicles, road traffic pressure is increasing, and traffic safety hazards (especially on semi-closed construction sections) have become a difficult problem to be solved. Due to the coexistence of construction and traffic on semi-closed highway construction sections, the road environment is complex and variable, and the line continuity and the line continuity of the curve region directly affect the dynamic safety of vehicles. According to statistics, traffic accidents on curve sections account for 10% of the total number of accidents, and death accidents account for as high as 20%. Due to factors such as equipment stacking and temporary adjustment of line shape on construction sections, the risk of limited visibility and insufficient turning radius is further aggravated.

[0003] Current highway visibility and curve radius detection mainly relies on two methods:

[0004] Manual experience and static instrument measurement: single-point detection is performed using devices such as level meters and total stations, which can only obtain static data at discrete positions and cannot cover the continuous line changes on the curve. Moreover, it is easily affected by construction obstacles.

[0005] Image processing technology: for example, a CCD camera collects curve images and calculates the radius through geometric algorithms, but relies on optical visibility conditions, and the accuracy decreases sharply in rainy, foggy or construction dust environments. Moreover, it is difficult to dynamically track real-time road conditions caused by construction. SUMMARY

[0006] Therefore, embodiments of the present specification provide a method and system for calculating the radius of a curve on a semi-closed highway construction section, and a computer storage medium, to solve the problems in the prior art that traditional on-site measurement and on-site survey can only identify single-point risk road sections and cannot accurately direct road risk warning.

[0007] Embodiments of the present specification adopt the following technical solutions:

[0008] The present specification provides a method for calculating the radius of a curve on a semi-closed highway construction section, which comprises:

[0009] Collecting a sequence of latitude and longitude coordinates of a detected section track, the detected section being a semi-closed highway construction section;

[0010] According to a preset sampling step, points are iteratively taken from the sequence of latitude and longitude coordinates to construct a triangle and an inscribed circle;

[0011] calculate the radius of the circumscribed circle to obtain a circumscribed circle radius set;

[0012] perform stable section detection on the circumscribed circle radius set through a sliding window;

[0013] perform average value calculation on the circumscribed circle radius data in the stable section to obtain the curve radius of the detection section.

[0014] The embodiment of the present specification also provides a semi-closed highway construction section curve radius calculation system, which comprises:

[0015] a collection module configured to collect a latitude and longitude coordinate sequence of a detection section track, the detection section being a semi-closed highway construction section;

[0016] a point taking module configured to take points from the latitude and longitude coordinate sequence iteratively according to a preset sampling step to construct a triangle and a circumscribed circle;

[0017] a first calculation module configured to calculate the radius of the circumscribed circle to obtain a circumscribed circle radius set;

[0018] a detection module configured to perform stable section detection on the circumscribed circle radius set through a sliding window;

[0019] a second calculation module configured to perform average value calculation on the circumscribed circle radius data in the stable section to obtain the curve radius of the detection section.

[0020] The embodiment of the present specification also provides a computer storage medium comprising a program used in combination with an electronic device, the program being executable by a processor to complete the following steps:

[0021] collecting a latitude and longitude coordinate sequence of a detection section track, the detection section being a semi-closed highway construction section;

[0022] taking points from the latitude and longitude coordinate sequence iteratively according to a preset sampling step to construct a triangle and a circumscribed circle;

[0023] calculating the radius of the circumscribed circle to obtain a circumscribed circle radius set;

[0024] performing stable section detection on the circumscribed circle radius set through a sliding window;

[0025] performing average value calculation on the circumscribed circle radius data in the stable section to obtain the curve radius of the detection section.

[0026] The above at least one technical solution adopted by the embodiment of the present specification can achieve the following beneficial effects:

[0027] By collecting the latitude and longitude coordinate sequence of the detected track of the section, the data of the curve can be automatically collected, and then the sampling step is set according to the preset sampling step, the iteration point is taken, the triangle and the circumscribed circle are constructed, the radius set of the circumscribed circle is calculated, the stable section detection is performed on the circumscribed circle set by using the sliding window, the average value of the radius data of the circumscribed circle in the stable section is calculated, and the radius of the curve of the detected section is obtained.

[0028] The full-automatic closed-loop process is realized without manual intervention, the calculated radius value is more accurate, is consistent with the characteristics of the circular curve itself in the curve, the circular curve section is accurately detected, the average radius of the circular curve section is output, the calculation result is more real and reliable, systematic errors caused by the characteristics of the transition curve are avoided, high-precision, automatic and efficient curve radius calculation is realized, and strong technical support is provided for the highway traffic safety hidden danger investigation. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings described herein are used to provide further understanding of the embodiments of the present specification, constitute a part of the present specification, and the illustrative embodiments of the present specification and the description thereof are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0030] Figure 1 A flowchart of a semi-closed highway construction section curve radius calculation method provided by the present specification is shown in the figure;

[0031] Figure 2 A circumscribed circle diagram of a detected track of a semi-closed highway construction section curve radius calculation method corresponding to the present specification is shown in the figure;

[0032] Figure 3 A sliding window average detection method diagram of a semi-closed highway construction section curve radius calculation method corresponding to the present specification is shown in the figure;

[0033] Figure 4 A flowchart of a specific application embodiment of a semi-closed highway construction section curve radius calculation method corresponding to the present specification is shown in the figure;

[0034] Figure 5 A structure diagram of a semi-closed highway construction section curve radius calculation system provided by the present specification is shown in the figure;

[0035] Figure 6 A structure diagram of a computer storage medium corresponding to a semi-closed highway construction section curve radius calculation method provided by the present specification is shown in the figure. DETAILED DESCRIPTION

[0036] In the prior art, in the current highway traffic safety hidden danger investigation work, most of them still use the traditional manual traffic safety hidden danger investigation method, which not only needs to consume a lot of manpower, but also the highway sight distance and the bend radius detection method have the problems of low efficiency, poor continuity, weak anti-interference, and cannot meet the needs of dynamic, high-precision, all-weather detection of semi-closed construction road section.

[0037] Therefore, it is necessary to improve the traditional manual traffic safety hidden danger investigation method by digitization, and the Beidou satellite navigation system (BDS) provides a new path to solve the above problems:

[0038] High-precision positioning capability: Beidou No. 3 system can realize centimeter-level positioning accuracy through real-time dynamic carrier phase difference (RTK) technology, and can be improved to decimeter or even centimeter level combined with ground-based enhancement system (such as Qianxun position).

[0039] Anti-interference and all-weather operation: Beidou's unique three-frequency signal and anti-shielding capability are suitable for complex environments such as mountainous areas and tunnels, breaking through the scene limitations of traditional optical equipment.

[0040] In the highway traffic safety hidden danger, the amount of highway traffic safety hidden danger caused by poor line shape (such as sharp turn, etc.) is large and the risk is high, and the road section is still in semi-closed construction, which is more disturbing to the driver. It is particularly important to identify and manage the hidden dangers of the relevant poor line shape. However, the current manual method for line shape surveying and setting is low in efficiency, time-consuming and inaccurate due to the difference in expert skills. Although the existing technology proposes a Beidou-based bend radius correction, it does not involve dynamic obstacle fusion calculation in the construction scene. The traditional measurement method (such as laser sensor) needs to preset fixed reflective barriers, which is difficult to adapt to the characteristics of random placement of equipment in the construction area.

[0041] Therefore, the embodiments of the present specification provide a semi-closed highway construction road section bend radius calculation method, system and computer storage medium, by collecting the latitude and longitude coordinate sequence of the detected road section track, the bend data can be automatically collected, then the preset sampling step is performed, the triangle and the circumscribed circle are constructed, the circumscribed circle radius set is calculated, the sliding window is used to detect the stable section of the circumscribed circle set, and the average value of the circumscribed circle radius data in the stable section is calculated to obtain the bend radius of the detected road section.

[0042] The full-automatic closed-loop process is realized without manual intervention, the calculated radius value is more accurate, which fits the characteristics of the circular curve itself in the bend, so that the circular curve section can be accurately detected, and the average radius of the circular curve section is output, the calculation result is more real and reliable, the systematic error caused by the characteristics of the transition curve is avoided, high-precision, automatic and efficient bend radius calculation is realized, and strong technical support is provided for the highway traffic safety hidden danger investigation work.

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments in this specification, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0044] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0045] like Figure 1 The diagram shown is a flowchart illustrating a method for calculating the curve radius of a semi-enclosed highway construction section, as provided in an embodiment of this specification.

[0046] In the embodiments of this specification, the method for calculating the curve radius of a semi-enclosed highway construction section may specifically include the following steps:

[0047] S101: Collect the latitude and longitude coordinate sequence of the detected road section trajectory, wherein the detected road section is a semi-closed highway construction section;

[0048] S103: According to the preset sampling step size, iteratively select points from the latitude and longitude coordinate sequence to construct a triangle and its circumcircle;

[0049] S105: Calculate the radius of the circumcircle to obtain the set of circumcircle radii;

[0050] S107: Detect stable segments of the set of circumcircle radii using a sliding window;

[0051] S109: Calculate the average value of the circumscribed circle radius data within the stable section to obtain the curve radius of the detected road section.

[0052] In the embodiments of this specification, by collecting BeiDou navigation scattered trajectory data, the latitude and longitude coordinate sequence of the detected road segment is obtained, and data analysis and calculation are performed to quickly reconstruct the parameters of the known curves, that is, to calculate the curve radius. This can assist in the investigation of potential road traffic safety hazards and quickly determine the potential adverse alignment scenarios.

[0053] As an application embodiment of this specification, step S101, which involves collecting the latitude and longitude coordinate sequence of the detected road segment trajectory, may specifically include:

[0054] The inspection vehicle, equipped with a Beidou navigation system, will pass through the inspection section at a predetermined speed.

[0055] Collect the latitude and longitude coordinates of the detected road section;

[0056] Smooth and unidirectionalize the longitude and latitude coordinates to eliminate positioning jitter to obtain the longitude and latitude coordinate sequence of the detected road section trajectory.

[0057] In the embodiments of the present specification, by mounting a Beidou navigation system on the detection vehicle, when the detection vehicle passes through the detection road section, the longitude and latitude coordinates of the detection road section can be automatically collected, and the detection road section trajectory can be automatically formed. The longitude and latitude data of the entire measured semi-closed construction road can be accurately and efficiently collected, which is not affected by weather and other conditions, and is safer and more reliable than the manual measurement of bend radius, and has high automation.

[0058] In specific application scenarios, to ensure the stability of the collected data, the detection vehicle needs to pass through the detection road section at a constant speed. The driving speed of the detection vehicle can be set according to the road grade of the detection road section.

[0059] For example, if the detection road section is a highway or a first-class highway, the driving speed of the detection vehicle is 60 km / h. In this case, the bend radius is large.

[0060] If the detection road section is a second-class road or below, the driving speed of the detection vehicle is 30-40 km / h. In this case, the bend radius is small.

[0061] After collecting the longitude and latitude coordinates, the original coordinate data is further smoothed and unidirectionalized to eliminate positioning jitter and reduce data error.

[0062] As an application embodiment of the present specification, for the step S103, the longitude and latitude coordinate sequence is iteratively sampled according to a preset sampling step to construct a triangle and an inscribed circle. Specifically, the step can include:

[0063] According to the time sequence of the collected data, the longitude and latitude coordinate sequence is iteratively sampled according to the preset sampling step;

[0064] Construct a triangle and an inscribed circle.

[0065] In the embodiments of the present specification, the longitude and latitude coordinate sequence obtained after processing is Beidou longitude and latitude scatter point data. In the same space, any three non-collinear points can form a triangle, which will form an inscribed circle radius. According to the planar linear feature, the curvature of the transition curve portion of the bend gradually changes, while the curvature of the circular curve portion is constant, and the radius of the circular curve is the bend radius. Therefore, in the longitude and latitude scatter point data of the bend, when three points are randomly selected in the circular curve portion to form a triangle, the inscribed circle radius output by constructing an inscribed circle can determine the bend radius of the detection road section.

[0066] For example, Figure 2As shown, a semi-closed highway construction section curve radius calculation method provided by an embodiment of the present specification corresponds to a detection section trajectory circumscribed circle schematic diagram.

[0067] From the longitude and latitude coordinate sequence, that is, in the obtained longitude and latitude scattered point data, according to the time sequence of collection, in a manner of preset sampling step n (selecting this step to be more close to the actual curve radius range), iteration is performed to take points, triangles and circumscribed circles are constructed, and the circumscribed circle radius R is output i .

[0068] The time sequence of collection is the collection time sequence of the longitude and latitude coordinate data.

[0069] According to the time sequence, the points are taken iteratively in sliding mode.

[0070] For example, the first time, 1, 1+n, 1+n+n are taken, and the circumscribed circle radius R1 is calculated;

[0071] The second time is 2, 2+n, 2+n+n, and the circumscribed circle radius R2 is calculated;

[0072] The third time is 3, 3+n, 3+n+n, and the circumscribed circle radius R3 is calculated;

[0073] … and so on

[0074] The i-th time is i, i+n, i+n+n, and the circumscribed circle radius R i .

[0075] Until the full trajectory of the detection section is covered, a plurality of different circumscribed circle radii are obtained.

[0076] Further, the preset sampling step is selected according to the road design speed of the detection section:

[0077] When the road design speed is greater than or equal to 80 km / h, the preset sampling step is selected to be 5;

[0078] When the road design speed is less than 60 km / h, the preset sampling step is selected to be 3.

[0079] After actual multi-round test verification, since the highway design speed (more than 80 km / h) is high, the curve radius is large, and the preset sampling step is preferably selected to be 5; and for the national and provincial roads with a design speed of less than 60 km / h, the curve radius is small, and the preset sampling step is preferably selected to be 3.

[0080] It should be noted that the preset sampling step can be adjusted according to actual needs, which is not specifically limited here.

[0081] As an application example of the present specification, for the step S105, the radius of the circumscribed circle is calculated to obtain a circumscribed circle radius set, which can be calculated according to the following formula:

[0082]

[0083] wherein R i is the circumscribed circle radius, and the three sides of the triangle are a, b and c respectively;

[0084] In the embodiments of the present specification, the above formula (1) is the Heron formula.

[0085] Specifically, the Haversine formula can also be used as the side length formula to calculate the side length of the triangle, i.e., the distance between the three scattered points in the latitude and longitude data. Assuming that two latitude and longitude coordinate points are A(bdlng1, bdlat1) and B(bdlng2, bdlat2), the distance between the two points is AB, which can be calculated according to the following formula:

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] Δλ = λ2- λ1 Formula (7)

[0092]

[0093]

[0094] AB = R·n Formula (10)

[0095] wherein R = 6371 is the radius of the earth, unit: kilometers (km).

[0096] The formula (2) means that the latitude of the first point is converted from degrees to radians, bdlat1 is the latitude of the first point, which is in degrees, and bdlat1' is the converted latitude, which is in radians.

[0097] The formula (3) means that the latitude of the second point is converted from degrees to radians, bdlat2 is the latitude of the second point, which is in degrees, and bdlat2' is the converted latitude, which is in radians.

[0098] The meaning of the formula (4) is to convert the longitude of the first point from degrees to radians, bd ln g1 is the longitude of the first point, and is in degrees, and λ1 is the converted latitude, which is in radians.

[0099] The meaning of the formula (5) is to convert the longitude of the second point from degrees to radians, bd ln g2 is the longitude of the second point, and is in degrees, and λ2 is the converted latitude, which is in radians.

[0100] The meaning of the formula (6) is the difference in latitude between the two points, and the unit is radian.

[0101] The meaning of the formula (7) is the difference in longitude between the two points, and the unit is radian.

[0102] The meaning of the formula (8) is to calculate the intermediate quantity of the great circle distance between the two points.

[0103] The meaning of the formula (9) is to calculate the central angle between the two points.

[0104] As an application example of the present specification, for the step S107, the stable segment detection is performed on the circumscribed circle radius set by using a sliding window, which can specifically include:

[0105] According to a preset window length, a sliding window is selected;

[0106] The circumscribed circle radius set is detected according to the collection time sequence;

[0107] The window variance of the circumscribed circle radius in the sliding window is calculated to obtain a plurality of output variance values;

[0108] The window with the minimum variance is selected from the plurality of output variance values as the stable segment.

[0109] In the embodiment of the present specification, according to the planar linear feature, the curvature of the transition curve portion in the curve gradually changes, and the curvature of the circular curve portion is constant, so the portion with stable numerical distribution in the output circumscribed circle radius data is the circular curve portion, and then only the stable segment of the circumscribed circle radius data needs to be detected, and the average value thereof is calculated to determine the curve radius of the detected road section.

[0110] Specifically, the stable segment detection can be performed on the circumscribed circle radius data by using a sliding window method. The data in the circumscribed circle radius set can be arranged in a table form according to the collection time sequence, and the circumscribed circle radius data in the detected stable segment tends to be a constant value, so the window variance calculation method can be used to detect the stable segment.

[0111] For example, Figure 3As shown, a sliding window mean detection method corresponding to a semi-closed highway construction section curve radius calculation method provided in the embodiments of the present specification.

[0112] It is known that the circumradius of the stable section tends to a constant value, so the method of calculating the window variance is used to detect the stable section.

[0113] In the embodiments of the present specification, a sliding window with a window length of 7 is selected, and the circumradius data set is detected in the order of collection time. The window variance of the data in the sliding window is calculated and the window with the minimum variance is output. It is determined that the stable section is determined, and the average value of the circumradius data in the stable section is calculated. The output window circumradius average value is the radius of the curve.

[0114] The window length is determined by the actual curve length and the number of scattered points. If the window length is too small, it will affect the accuracy of the stable section detection, and there may be false judgments to the transition curve. If the window length is too large, it will affect the accuracy of the final calculated curve radius value. Therefore, in the actual application process, the window length is selected according to the actual demand, which is not specifically limited here.

[0115] As an application embodiment of the present specification, for the step S109, after obtaining the curve radius of the detected section, the method can further include:

[0116] Record the output curve radius on the map.

[0117] In the embodiments of the present specification, by recording the output curve radius on the map, it is convenient for later verification and hidden danger investigation work.

[0118] The semi-closed highway construction section curve radius calculation method provided in the embodiments of the present specification can realize automatic collection of curve data by collecting the latitude and longitude coordinate sequence of the detected section track, and then iteratively taking points according to the preset sampling step, constructing a triangle and a circumcircle, calculating the circumradius set, using a sliding window to detect the stable section, and calculating the average value of the circumradius data in the stable section to obtain the curve radius of the detected section.

[0119] The full-automatic closed-loop process is realized without manual intervention, the calculated radius value is more accurate, and it fits the characteristics of the circular curve itself, so that the circular curve section can be accurately detected, and the average value of the radius of the circular curve section is output. The calculation result is more real and reliable, avoids systematic errors caused by the characteristics of the transition curve, realizes high-precision, automatic, and efficient curve radius calculation, and provides strong technical support for highway traffic safety hidden danger investigation work.

[0120] It should be noted that the specific semi-closed road construction section curve radius calculation method described above is only used as a specific application example, and does not limit the scope of the embodiments of the present application, and other specific embodiments can also be included, which will not be repeated here.

[0121] Based on the same inventive concept, the embodiments of the present application also provide a specific application example of the semi-closed road construction section curve radius calculation method described above.

[0122] As shown in Figure 4 The semi-closed road construction section curve radius calculation method provided by the embodiments of the present application corresponds to the flowchart of the specific application example.

[0123] Among them, the semi-closed road construction section curve radius automatic calculation method based on Beidou positioning can specifically include the following steps:

[0124] Step 1: Beidou positioning data acquisition;

[0125] Step 2: trajectory preprocessing;

[0126] Step 3: iterative circumscribed circle calculation;

[0127] Step 4: sliding window variance detection;

[0128] Step 5: stable section radius output;

[0129] Step 6: hidden danger map annotation.

[0130] In the embodiments of the present application, for the step 1 and the step 2, device configuration and data acquisition are included.

[0131] Among them, the hardware device:

[0132] Beidou high-precision positioning terminal: specifically, a dual-frequency receiver (for example, Huachuang navigation P5 series, etc.) supporting BDS-3 (Beidou No. 3) can be selected, and centimeter-level positioning accuracy (horizontal positioning error ≤2cm) is achieved through RTK (Real-Time Kinematic) technology.

[0133] Beidou is the full name of Beidou satellite navigation system (BeiDou Navigation Satellite System, BDS); RTK is the full name of real-time dynamic carrier phase difference (Real-Time Kinematic).

[0134] Vehicle-mounted data acquisition system: industrial-grade tablet computer (with data storage module), which communicates with the Beidou terminal through a serial port or CAN bus.

[0135] Auxiliary sensor: vehicle-mounted IMU (inertial measurement unit) for compensating vehicle attitude changes (optional).

[0136] Installation and calibration:

[0137] Fix the Beidou antenna at the center of the vehicle roof, ensuring no obstruction (avoiding interference with signals by construction equipment).

[0138] Initialize the Beidou device, access the ground-based enhancement network (e.g., FindCM service), and obtain the RTK fixed solution.

[0139] Data collection process:

[0140] 1. Detect the vehicle to enter the semi-closed construction section at a constant speed (example: G102 National Highway K120+500 to K121+200 construction zone);

[0141] Wherein, the vehicle speed is controlled according to the road grade:

[0142] For expressways / first-class highways: 60km / h (large radius of curves);

[0143] For secondary and below highways: 30-40km / h (small radius of curves).

[0144] 2. The data collection software records the Beidou longitude and latitude coordinates (fields: bdlng, bdlat), timestamp, and vehicle speed at a frequency of 10Hz.

[0145] 3. Smooth the original coordinates (Savitzky-Golay filter, window length = 5) to eliminate positioning jitter, which is the trajectory preprocessing step.

[0146] Automatic collection of curve data: By mounting the Beidou navigation system on the vehicle and driving along the measured semi-closed construction section, automatic collection is performed. The technical effect lies in: accurately and efficiently collecting longitude and latitude data of the entire measured semi-closed construction highway, unaffected by weather and other conditions, and more safe and reliable compared to manual measurement of curve radius, with high automation. This solves the problem of traditional manual inspection and measurement, reduces the risk of outdoor exposure for workers, saves time and effort, and has high automation.

[0147] Further, for step 3, an iterative construction of an inscribed circle is performed.

[0148] Data segmentation: Identify the start and end points of the curve based on curvature changes (example: K120+700 to K121+000).

[0149] Iterative point selection strategy (key parameters):

[0150] Python code (# step length n setting rules:

[0151] if road design speed >= 80km / h: # expressway / 1st class highway

[0152] n = 5 # large radius curve, point interval ~ 15m (10Hz sampling)

[0153] else: # below 2nd class highway

[0154] n = 3 # small radius curve, point interval ~ 9m

[0155] Point sampling example:

[0156] Group 1: point index [1, 1+n, 1+2n] -> coordinates P1, P6, P 11

[0157] Group 2: point index [2, 2+n, 2+2n] -> coordinates P2, P7, P 12

[0158] ... and so on, until all points on the curve are covered.

[0159] Further, the circumradius is calculated using the Heron formula.

[0160] • Triangle side length calculation (Haversine formula):

[0161] Python code (import numpy as np

[0162] def haversine(lon1, lat1, lon2, lat2):

[0163] R = 6371.0 # Earth radius (km)

[0164] dlat = np.radians(lat2 - lat1)

[0165] dlon = np.radians(lon2 - lon1)

[0166] a = np.sin(dlat / 2) ** 2 + np.cos(np.radians(lat1)) * np.cos(np.radians(lat2)) * np.sin(dlon / 2) ** 2

[0167] c = 2 * np.arctan2(np.sqrt(a), np.sqrt(1 - a))

[0168] return R * c * 1000 # Convert to meters

[0169] Circumradius formula:

[0170] Python code (def circumradius(a,b,c): # a,b,c are triangle side length

[0171] p = (a + b + c) / 2

[0172] area = np.sqrt(p * (p - a) * (p - b) * (p - c)) # Heron formula for area

[0173] return (a * b * c) / (4 * area) # Circumradius R_i)

[0174] Further, for the step 4 and the step 5, a sliding window detects stable segments.

[0175] Window parameters include:

[0176] Window length: 7 groups of circumradius data (empirical value, balance sensitivity and noise resistance)

[0177] Sliding step: 1 group of data

[0178] • Variance calculation and stable segment determination:

[0179] Python code (radius_list = [R1, R2,..., Rk] # All circumradius

[0180] min_variance = float('inf')

[0181] stable_segment = []

[0182] for i in range(len(radius_list) - 6):

[0183] window = radius_list[i:i+7]

[0184] variance = np.var(window) # Calculate window variance

[0185] if variance < min_variance:

[0186] min_variance = variance

[0187] stable_segment = window # Marked as stable segment

[0188] curve_radius = np.mean(stable_segment) # Curve radius )

[0189] Decision logic: stable segment variance threshold set to 5m 2 (Statistical value of the radius fluctuation of the circular curve segment), if the variance threshold is too strict, it may miss detection, and if it is too wide, it may contain a non-circular curve. If min_variance < 5, accept the result, that is, determine the stable segment, and the average of the radii of the circumscribed circle of the stable segment is the radius of the detected curve.

[0190] The radius calculation accuracy is high, and the variance detection mechanism is more in line with the characteristics of the curve. In the development of related algorithms, most algorithms use isolated triangle curvature calculation and take the average value method. Due to the characteristics of the transition curve, the radius is inaccurate. In the embodiment of the present specification, iterative triangle calculation is used, and the straight line distance formula is discarded by using the latitude and longitude distance formula. Hellen formula is used for calculation, and finally the variance detection mechanism is added to output the curve radius.

[0191] The technical effect is that the calculated radius value is more accurate and fits the characteristics of the circular curve in the curve, so that the circular curve segment can be accurately detected and the average radius of the circular curve segment can be output. The calculation result is more real and reliable, and systematic errors caused by the characteristics of the transition curve are avoided, which directly overcomes the problem of inaccurate measurement in the prior art.

[0192] Further, for the step 6, hidden danger labeling and output:

[0193] Compare with the limit value of "Highway Route Design Specification", automatically mark the poor linear segment;

[0194] Generate a curve radius heat map and risk level label on the map.

[0195] The semi-closed highway construction segment curve radius calculation method provided by the embodiment of the present specification has a wide range of applications, and is used for positioning and surveying on highways of all levels in China. For low-grade roads and rural highways, due to the lack of kilometer posts, it is not possible to accurately position the poor linear scene, and only reference objects can be used for positioning. The technical effect is that due to the characteristics of Beidou navigation, traditional kilometer posts are not used for positioning, and the calculation of the curve radius of multi-grade highways can be realized, and the positioning and determination of the poor linear hidden danger scene of multi-grade highways can be realized.

[0196] It can also improve road safety and traffic efficiency:

[0197] (1) Social benefits: accurately and efficiently identify poor linear hidden danger scenes, provide scientific basis for timely targeted management measures (such as adding warning signs), directly help to reduce the traffic accident rate of this hidden danger scene, and protect the life safety of passing drivers and passengers. ​

[0198] (2) Economic benefits: Automatic measurement greatly reduces manual input and measurement time, reducing measurement cost. At the same time, preventive measures avoid high life and property losses, traffic delay costs that may be caused by accidents. In addition, clear dangerous road segment signs also help optimize traffic flow, reduce speed and congestion caused by poor visibility, and improve overall traffic efficiency on the construction road segment.

[0199] In addition, it is easy to operate and easy to popularize and apply: based on mature vehicle-mounted platforms and curve radius calculation algorithms, the process is clear (installation, measurement, recording, calculation, inspection, output), and the required equipment is relatively common and the cost is controllable. The technical effect is embodied in: the method is easy to understand and operate by highway maintenance, traffic police and other departments, and has good engineering practicability and popularization prospect.

[0200] In summary, the method provided by the embodiments of the present specification effectively overcomes the core defects of low automation, low efficiency, and low accuracy of existing highway measurement methods when applied to curves, achieving high-precision, automated, and efficient curve radius calculation, and providing strong technical support for highway traffic safety hazard investigation.

[0201] The specific implementation process of the embodiments of the present specification can refer to the respective implementation steps of the above-mentioned embodiments, which will not be repeated here.

[0202] Based on the same inventive concept, the embodiments of the present specification also provide a curve radius calculation system for a semi-closed highway construction road segment. As shown in Figure 5 Fig. 1 is a structural schematic diagram of a curve radius calculation system for a semi-closed highway construction road segment provided by an embodiment of the present specification.

[0203] The curve radius calculation system for a semi-closed highway construction road segment can specifically include:

[0204] The acquisition module 501 acquires the latitude and longitude coordinate sequence of the detected road segment track, and the detected road segment is a semi-closed highway construction road segment;

[0205] The point taking module 502 takes points from the latitude and longitude coordinate sequence according to a preset sampling step to construct a triangle and an incircle;

[0206] The first calculation module 503 calculates the radius of the incircle to obtain an incircle radius set;

[0207] The detection module 504 detects the stable section of the incircle radius set through a sliding window;

[0208] The second calculation module 505 calculates the average value of the incircle radius data in the stable section to obtain the curve radius of the detected road segment.

[0209] Based on Figure 5 the system, the embodiments of the present specification also provide some specific embodiments of the system, which are described below.

[0210] Further, the latitude and longitude coordinate sequence of the detection section track is collected, including:

[0211] The detection vehicle passes through the detection section at a predetermined speed, and the detection vehicle is equipped with a Beidou navigation system;

[0212] The latitude and longitude coordinates of the detection section are collected;

[0213] The latitude and longitude coordinates are smoothed and unidirectionalized to eliminate positioning jitter, and the latitude and longitude coordinate sequence of the detection section track is obtained.

[0214] Further, according to a preset sampling step, points are iteratively taken from the latitude and longitude coordinate sequence to construct a triangle and an inscribed circle, including:

[0215] According to the time sequence of collection, the points are iteratively taken according to the preset sampling step;

[0216] The triangle and the inscribed circle are constructed.

[0217] Further, the points are iteratively taken from the latitude and longitude coordinate sequence, including:

[0218] The first time is 1, 1+n, 1+n+n, and the corresponding inscribed circle radius is R1;

[0219] The second time is 2, 2+n, 2+n+n, and the corresponding inscribed circle radius is R2;

[0220] The third time is 3, 3+n, 3+n+n, and the corresponding inscribed circle radius is R3;

[0221] The i-th time is i, i+n, i+n+n, and the corresponding inscribed circle radius is R i .

[0222] Further, the preset sampling step is selected according to the road design speed of the detection section:

[0223] When the road design speed is ≥80km / h, the preset sampling step is selected as 5;

[0224] When the road design speed is <60km / h, the preset sampling step is selected as 3.

[0225] Further, the radius of the inscribed circle is calculated to obtain an inscribed circle radius set, which can be calculated according to the following formula:

[0226]

[0227] wherein R i is the circumradius, and the three sides of the triangle are a, b, and c, respectively;

[0228] Further, the circumradius set is detected by a sliding window for stable section detection, including:

[0229] According to a preset window length, a sliding window is selected;

[0230] The circumradius set is detected according to the collection time sequence;

[0231] The circumradius in the sliding window is calculated for window variance to obtain a plurality of output variance values;

[0232] From the plurality of output variance values, a window with the minimum variance is selected as a stable section.

[0233] Further, after the curve radius of the detection section is obtained, the system further includes:

[0234] The output curve radius is recorded on a map.

[0235] The semi-closed highway construction section curve radius calculation system provided by the embodiments of the present specification can realize automatic collection of curve data by collecting the latitude and longitude coordinate sequence of the detection section track, and then iteratively selects points according to a preset sampling step, constructs a triangle and a circumcircle, calculates a circumradius set, detects the stable section of the circumradius set by using a sliding window, calculates the average value of the circumradius data in the stable section, and obtains the curve radius of the detection section.

[0236] The full-automatic closed-loop process is realized without manual intervention, the calculated radius value is more accurate, and is consistent with the characteristics of the circular curve itself in the curve, so that the circular curve section can be accurately detected, and the average radius of the circular curve section is output, the calculation result is more real and reliable, systematic errors caused by the characteristics of the transition curve are avoided, high-precision, automatic, and efficient curve radius calculation is realized, and strong technical support is provided for highway traffic safety hidden danger investigation work.

[0237] Based on the same inventive concept, the embodiments of the present specification also provide an electronic device including at least one processor and a memory, the memory stores a program and is configured to be executed by the at least one processor to perform the following steps:

[0238] Collecting a latitude and longitude coordinate sequence of a detection section track, the detection section being a semi-closed highway construction section;

[0239] iteratively taking points from the sequence of latitude and longitude coordinates according to a preset sampling step length to construct a triangle and a circumscribed circle;

[0240] calculating a radius of the circumscribed circle to obtain a circumscribed circle radius set;

[0241] performing stable section detection on the circumscribed circle radius set through a sliding window;

[0242] performing average value calculation on the circumscribed circle radius data in the stable section to obtain a curve radius of the detected road section.

[0243] Other functions of the processor can also refer to the content described in the above embodiments, which will not be repeated here.

[0244] Based on the same inventive concept, the embodiments of the present specification also provide a computer readable storage medium comprising a program for use in conjunction with an electronic device, the program being executable by a processor to complete the following steps:

[0245] collecting a sequence of latitude and longitude coordinates of a detected road section, the detected road section being a semi-closed highway construction road section;

[0246] iteratively taking points from the sequence of latitude and longitude coordinates according to a preset sampling step length to construct a triangle and a circumscribed circle;

[0247] calculating a radius of the circumscribed circle to obtain a circumscribed circle radius set;

[0248] performing stable section detection on the circumscribed circle radius set through a sliding window;

[0249] performing average value calculation on the circumscribed circle radius data in the stable section to obtain a curve radius of the detected road section.

[0250] Other functions of the processor can also refer to the content described in the above embodiments, which will not be repeated here.

[0251] As shown in Figure 6 the embodiments of the present specification also provide a structural diagram of a computer storage medium.

[0252] The system, device, module or unit illustrated in the above embodiments can be specifically implemented by a computer chip or entity, or by a product with certain functions. A typical implementation device is a computer. Specifically, the computer may, for example, be a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0253] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the present application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer readable storage media (including, but not limited to, disk memory, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0254] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0255] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0256] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0257] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0258] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) and / or cache memory. The memory can also include non-volatile memory, such as read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), flash memory, or a combination of non-volatile memories in different forms. The memory is an example of computer readable storage media.

[0259] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0260] It should also be noted that the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices that include a series of elements not only include those elements, but also include other elements not explicitly listed or inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0261] The present application can be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. The present application can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are connected through a communication network. In a distributed computing environment, program modules can be located in both local and remote computer storage media including storage devices.

[0262] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0263] The above merely provides an example of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for calculating the radius of a curve on a semi-closed highway construction section, characterized in that, The semi-closed highway construction section curve radius calculation method comprises: Collecting a latitude and longitude coordinate sequence of a track of a detection section, the detection section being a semi-closed highway construction section; According to a preset sampling step, points are iteratively taken from the latitude and longitude coordinate sequence to construct a triangle and an inscribed circle; The radius of the inscribed circle is calculated to obtain an inscribed circle radius set; A stable section of the inscribed circle radius set is detected through a sliding window; The average value of the inscribed circle radius data in the stable section is calculated to obtain the curve radius of the detection section.

2. The method of claim 1, wherein, Collecting a latitude and longitude coordinate sequence of a track of a detection section, comprising: According to a predetermined speed, a detection vehicle passes through the detection section, the detection vehicle being equipped with a Beidou navigation system; Collecting latitude and longitude coordinates of the detection section; The latitude and longitude coordinates are smoothed and unidirectionalized to eliminate positioning jitter to obtain the latitude and longitude coordinate sequence of the track of the detection section.

3. The method of claim 2, wherein, According to a preset sampling step, points are iteratively taken from the latitude and longitude coordinate sequence to construct a triangle and an inscribed circle, comprising: According to the time sequence of collection, points are iteratively taken according to the preset sampling step; A triangle and an inscribed circle are constructed.

4. The method of claim 3, wherein, Iteratively taking points from the latitude and longitude coordinate sequence, comprising: Firstly, 1, 1+n, and 1+n+n are taken, and the corresponding inscribed circle radius is R1; Secondly, 2, 2+n, and 2+n+n are taken, and the corresponding inscribed circle radius is R2; Thirdly, 3, 3+n, and 3+n+n are taken, and the corresponding inscribed circle radius is R3; The i-th is i, i+n, i+n+n, and the corresponding circumscribed circle radius is R i .

5. The method of claim 3, wherein, The preset sampling step is selected according to the road design speed of the detection section: When the road design speed is greater than or equal to 80 km / h, the preset sampling step is selected to be 5; When the road design speed is less than 60 km / h, the preset sampling step is selected to be 3.

6. The method of claim 4, wherein, The radius of the inscribed circle is calculated to obtain an inscribed circle radius set, which can be calculated according to the following formula: wherein R i is the radius of the circumscribed circle, and the three sides of the triangle are A, b, and c, respectively; 7. The method of claim 1, wherein, A stable section of the inscribed circle radius set is detected through a sliding window, comprising: According to a preset window length, a sliding window is selected; The inscribed circle radius set is detected according to the collection time sequence; Window variance calculation is performed on the inscribed circle radius in the sliding window to obtain a plurality of output variance values; The window with the smallest variance is selected from the plurality of output variance values as the stable section.

8. The method of claim 1, wherein, After obtaining the curve radius of the detection section, the method further comprises: The output curve radius is recorded on a map.

9. A system for calculating the radius of a curve on a semi-closed highway construction section, characterized in that, The semi-closed highway construction section curve radius calculation system comprises: A collection module that collects a latitude and longitude coordinate sequence of a track of a detection section, the detection section being a semi-closed highway construction section; A point taking module that iteratively takes points from the latitude and longitude coordinate sequence according to a preset sampling step to construct a triangle and an inscribed circle; A first calculation module that calculates the radius of the inscribed circle to obtain an inscribed circle radius set; A detection module that detects a stable section of the inscribed circle radius set through a sliding window; A second calculation module that calculates the average value of the inscribed circle radius data in the stable section to obtain the curve radius of the detection section.

10. A computer storage medium, comprising a program for use in combination with an electronic device, which program can be executed by a processor to accomplish the following steps: Collecting a sequence of latitude and longitude coordinates of a track of a detection section, the detection section being a semi-closed highway construction section; According to a preset sampling step, iteratively taking points from the sequence of latitude and longitude coordinates to construct a triangle and an incircle; Calculating a radius of the incircle to obtain a set of incircle radii; Performing stable section detection on the set of incircle radii by a sliding window; Performing average value calculation on the incircle radius data in the stable section to obtain a curve radius of the detection section.

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