A Method for Determining Traffic Flow Trajectories at Intersections

A traffic flow and intersection technology, applied in the direction of traffic flow detection, etc., can solve the problems of non-motor vehicles and pedestrians, and achieve the effect of reducing personal casualties and property losses, improving traffic order and efficiency, and reducing exhaust emissions.

Active Publication Date: 2017-02-01
YANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the greater randomness of non-motor vehicles and pedestrians, its driving trajectory is not a simple straight line or curve.

Method used

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  • A Method for Determining Traffic Flow Trajectories at Intersections
  • A Method for Determining Traffic Flow Trajectories at Intersections
  • A Method for Determining Traffic Flow Trajectories at Intersections

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A method for determining the trajectory of traffic flow at an intersection is characterized by comprising the following steps:

[0023] 1) Obtain several images by collecting video files, and use the view software to obtain the coordinates of any kind of traffic flow in the image coordinate system at any time from the collected images, that is, the image coordinates (x t ,y t );

[0024] 2) Establish traffic flow image coordinates (x t ,y t ) and its corresponding actual coordinates (x d ,y d ) between the mutual conversion relationship:

[0025] a. Select 4 known feature points for calibration by on-site measurement, and establish a coordinate system by measuring the size to obtain the actual coordinates of the calibration points, that is (x gc,1 ,y gc,1 ),(x gc,2 ,y gc,2 ),(x gc,3 ,y gc,3 ),(x gc,4 ,y gc,4 ), and its corresponding image coordinates can be obtained directly through the view software, namely (x ic,1 ,y ic,1 ),(x ic,2 ,y ic,1 ),(x ic,3 ...

Embodiment 2

[0029] Taking the intersection of Wenchang Road and North University Road in Yangzhou City as an example, the steps to determine the trajectory of non-motorized vehicles at this intersection are as follows:

[0030] 1) Select 4 calibration points that can surround the research area, and the positions and coordinates of the 4 calibration points are shown in figure 2 :

[0031] Through the processing of the image file (view software) and the actual measurement of the intersection, the image coordinates (pixels) and actual coordinates (m) of the calibration point are respectively x ic,1 =458,y ic,1 =268,x ic,2 =19,y ic,2 =707,x ic,3 =1767,y ic,3 =625,x ic,4 =1674,y ic,4 =1055;x gc,1 =0,y gc,1 =0,x gc,2 =0,y gc,2 =34,x gc,3 =51,y gc,3 =0,x gc,4 =51,y gc,4 = 24;

[0032] 2) Select a representative 5-min interval in the video file as the research time period, collect 1 picture every 1 s, and collect 300 pictures in total, and draw all the actual coordinates inside t...

Embodiment 3

[0034] A method for determining the trajectory of traffic flow at an intersection, comprising the steps of:

[0035] 1) By collecting continuous dynamic images of traffic flow, the coordinates of traffic individuals in the image coordinate system can be obtained through the corresponding view software, that is, the image coordinates (x t ,y t );

[0036] 2) Select 4 known feature points for calibration by on-site measurement, and establish a coordinate system by measuring the size to obtain the actual coordinates of the calibration points (x d ,y d ), its corresponding image coordinates can be obtained by image software;

[0037] 3) According to the conversion formula of actual coordinates and image coordinates, namely The actual coordinates of traffic individuals at any position in the image can be obtained, where c 1 -c 8 is the coefficient of matrix conversion, which can be obtained from the image coordinates and actual coordinates of 4 known calibration points;

...

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Abstract

A method for determining the trajectory of traffic flow at an intersection, which relates to the field of traffic conflict of mixed traffic flow in traffic engineering. The image coordinates of a traffic individual are obtained through the view software, and the actual coordinates of a traffic individual at any time can be obtained through the conversion formula of image coordinates and actual coordinates. There are 8 unknown matrix conversion coefficients in the conversion formula, and the matrix conversion coefficients can be obtained by marking 4 points with known image coordinates and actual coordinates at the intersection, and bringing the image coordinates and actual coordinates of the marked points into the conversion formula. On the basis of determining the 8 conversion coefficients, the actual coordinates of a certain traffic individual at all times to be obtained are obtained, and the coordinate system is drawn to be the driving trajectory of the traffic individual. The invention has important significance for the quantification of traffic conflicts at intersections, the prediction of black spots of traffic accidents and the improvement of traffic safety.

Description

technical field [0001] The invention relates to a method for determining the trajectory of traffic flow at an intersection through mutual conversion between image coordinates and actual coordinates, and relates to the field of mixed traffic flow traffic conflicts in traffic engineering. Background technique [0002] With the development of urban economy, the problem of traffic conflicts at intersections has become increasingly prominent. Conflicts between different types of traffic flows at an intersection must meet two conditions: one is that the trajectories of different traffic flows have conflict points inside the intersection; the other is that different traffic flows arrive at the conflict point at the same time. Therefore, it is very important to study the traffic flow trajectory. [0003] In order to represent the conflict points of different traffic flows at intersections, a common practice is to use a straight line or curve to represent the trajectory of the traff...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G08G1/01
Inventor 沈家军王群曹志铭
Owner YANGZHOU UNIV
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