A vehicle head avoidance system and vehicle head recognition method based on laser radar

Abstract

The present application provides a vehicle head avoidance system and vehicle head recognition method based on laser radar, the system includes: a laser radar, which is used to collect image data composed of a series of polar coordinates from the radar to the inspected vehicle; a radiation imaging inspection system, which is used to emit X-rays and scan the inspected vehicle to complete radiation imaging; and a vehicle head recognition controller whose input end is connected to the laser radar and whose output end is connected to the radiation imaging inspection system, which is used to receive radar image data and control the radiation imaging system to emit rays. When the vehicle head just passes the ray port, the radiation imaging inspection system can be controlled to scan the vehicle body starting from the container, effectively avoiding the vehicle head, protecting the driver in the cab from radiation damage, and at the same time completely scanning the container. It solves the problem that the traditional radiation imaging inspection system performs a radiation scan on the entire container to be inspected, and the cab personnel do not have any safety protection, which brings potential harm to the cab personnel.

Description

Technical Field

[0001] The present invention relates to the field of radiation imaging technology, and in particular to a vehicle head avoidance system and a vehicle head recognition method based on laser radar. Background Art

[0002] Container imaging inspection systems are widely used in customs, civil aviation airports and railway transportation systems. Using the principle of radiation imaging, the imaging inspection system scans the inspected container without opening the container to check whether there are any prohibited items in the container.

[0003] However, currently most radiation imaging inspection systems perform radiation scans on the entire vehicle, including the front of the vehicle. X-rays are electromagnetic waves with strong radiation, which undoubtedly poses potential harm to people in the front cab of the vehicle. Summary of the invention

[0004] In view of this, the main purpose of the present invention is to solve the problem that the crew in the cab is easily harmed by radiation when completely scanning the container.

[0005] The present invention provides a vehicle head avoidance system based on laser radar, comprising: a laser radar for collecting image data consisting of a series of polar coordinates from the radar to the inspected vehicle; a radiation imaging inspection system for emitting X-rays and scanning the inspected vehicle to complete radiation imaging; and a vehicle head recognition controller having an input end connected to the laser radar and an output end connected to the radiation imaging inspection system, for receiving radar image data and controlling the radiation imaging system to emit rays.

[0006] In some embodiments of the present invention, the radiation imaging inspection system includes an X-ray emitting device and an imaging detector connected to the X-ray emitting device, wherein the X-ray emitting device is used to emit X-rays, and the imaging detector is used to scan the inspected vehicle and complete radiation imaging.

[0007] In some embodiments of the present invention, the vehicle head recognition controller is fixedly installed in the X-ray emitting device and connected to the X-ray emitting device.

[0008] The present invention also provides a vehicle head recognition method based on laser radar, comprising: step S101, installing the laser radar based on the radar vertical angle correction algorithm; step S102, when there is a vehicle at a preset position in the channel, the laser radar obtains the distance d between the installation point of the laser radar and the current front end point of the vehicle head 0 And the angle θ between the line from the installation point of the laser radar to the current front end of the vehicle and the vertical direction 0 , so as to calculate the horizontal distance D between the front edge of the current vehicle and the laser radar 0 =d 0 sinθ0 Step S103: The laser radar scans along the front contour and obtains pixels at a certain position, and obtains the distance d between the laser radar and a certain position. 1 And the angle θ between the line from the installation point of the laser radar to a certain position and the vertical direction 1 , calculate the height h between a certain position and the laser radar 1 =H 0 -d 1 cosθ 1 ;

[0009] Step S104, when the height h between a certain position and the laser radar 10 1 is greater than the height between the next position and the laser radar 10, and determines the horizontal distance D between a certain position and the laser radar 10 1 The horizontal distance D between the front edge of the current vehicle and the laser radar 10 0 Is the difference between the two greater than the first preset value and less than the second preset value? Step S105: if the horizontal distance D between a certain position and the laser radar 1 The horizontal distance D between the front edge of the vehicle and the laser radar 0 If the difference between the two is greater than the first preset value and less than the second preset value, the head length HeadLen is calculated as D 1 -D 0 .

[0010] In some embodiments of the present invention, after step S105, the method further includes: controlling the vehicle head recognition controller to set the start and stop time interval of the X-ray emitting device to Second = HeadLen / Speed ​​according to the current vehicle speed value Speed ​​acquired by the laser radar.

[0011] The present invention provides a vehicle head avoidance system and vehicle head recognition method based on laser radar, which uses laser radar to collect image data of the inspected vehicle and accurately identify the length of the vehicle head. When the vehicle head just passes the radiation port, the radiation imaging inspection system can be controlled to scan the vehicle body from the container, effectively avoiding the vehicle head and protecting the driver in the cab from radiation damage, while completely scanning the container. This solves the problem that the traditional radiation imaging inspection system performs a radiation scan on the entire container being inspected, while the cab personnel do not have any safety protection, causing potential harm to the cab personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural block diagram of a vehicle head avoidance system based on laser radar according to an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of a containerless vehicle head recognition model according to an embodiment of the present invention;

[0014] Figure 3 This is a flow chart of a container-free vehicle head avoidance algorithm according to an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of a container vehicle head recognition model according to an embodiment of the present invention;

[0016] Figure 5 This is a flow chart of an algorithm for avoiding a vehicle head with a container according to an embodiment of the present invention;

[0017] Figure 6 The figure is a schematic diagram of radar vertical angle correction triangulation according to one embodiment of the present invention.

[0018] The above drawings include the following reference numerals:

[0019] 10. Laser radar; 20. Radiation imaging inspection system; 21. X-ray emission device; 22. Imaging detector; 30. Vehicle head recognition controller. DETAILED DESCRIPTION

[0020] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It will be appreciated that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only portions related to the relevant inventions are shown in the accompanying drawings. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0021] See also Figure 1 , which shows a laser radar-based vehicle head avoidance system of the present application, including: a laser radar 10, used to collect image data consisting of a series of polar coordinates from the radar to the inspected vehicle; a radiation imaging inspection system 20, used to emit X-rays and scan the inspected vehicle to complete radiation imaging; and a vehicle head recognition controller 30 whose input end is connected to the laser radar 10 and whose output end is connected to the radiation imaging inspection system 20, used to receive radar image data and control the radiation imaging system 20 to emit rays.

[0022] By applying the technical solution of this embodiment, the laser radar 10 is used to collect the image data of the inspected vehicle and accurately identify the length of the front of the vehicle. When the front of the vehicle just passes the radiation port, the front of the vehicle recognition controller 30 can control the radiation imaging inspection system 20 to scan the vehicle body from the container, effectively avoiding the front of the vehicle, protecting the driver in the cab from radiation damage, and at the same time completely scanning the container. This solves the problem that the traditional radiation imaging inspection system performs radiation scanning on the entire container under inspection, while the cab personnel have no safety protection, which brings potential harm to the cab personnel.

[0023] In some optional embodiments, the radiation imaging inspection system 20 includes an X-ray emitting device 21 and an imaging detector 22 connected to the X-ray emitting device, wherein the X-ray emitting device 21 is used to emit X-rays, and the imaging detector 22 is used to scan the inspected vehicle and complete radiation imaging.

[0024] Specifically, the vehicle head recognition controller 30 is fixedly installed in the X-ray emitting device 21 and connected to the X-ray emitting device 21 .

[0025] Since the inspected vehicles have different shapes of fronts, some are loaded with containers, some are flatbed trailers without containers, and some have fronts that are flush with the carriage, it is difficult to identify the fronts. It is necessary to classify various fronts, extract the main features of the fronts, and develop a front recognition algorithm. The inspected vehicles are classified as follows: front recognition without containers and front recognition with containers.

[0026] Figure 2 Schematic diagram of the vehicle head recognition model without container in the embodiment of the present invention. Its characteristics are that the vehicle head is the highest, and there is a flat rack behind the vehicle head without container. Based on this characteristic, a vehicle head recognition algorithm without container is designed.

[0027] See also Figure 3 , the vehicle head recognition method without container includes the following steps:

[0028] Step S101, the system needs to detect whether there is a car in the channel.

[0029] Step S102: When a vehicle is detected in the channel, the system obtains the distance d between the laser radar 10 and the front edge of the current vehicle. 0 and the angle θ between the line from the installation point of the laser radar 10 to the current front end of the vehicle and the vertical direction 0 , so as to calculate the horizontal distance D between the front edge of the current vehicle and the laser radar 10 0 =d 0 sinθ 0 ;

[0030] Step S103, scanning along the front contour and obtaining a pixel at the front position, by obtaining the distance d between the laser radar 10 and a certain position 1 and the angle θ between the line from the installation point of the laser radar (10) to a certain position and the vertical direction 1 , calculate the height h between a certain position and the laser radar 10 1 =H 0 -d 1 cosθ 1 ;

[0031] Step S104, obtaining the vehicle height at the next position again: h 2 =H 0 -d 2 cosθ 2 , save the corresponding angle θ 2 ;

[0032] Step S105, determining the height h between a certain position and the laser radar 10 1 Greater than the height between the next position and the laser radar 10, wherein the next position refers to the next position of a certain position, for example, the detected positions include position point 1, position point 2, position point 3, and position point 4; when a certain position is position point 2, the next position only refers to position point 3.

[0033] Step S106, when the height h between a certain position and the laser radar 10 1 When it is greater than the height between the next position and the laser radar 10, the horizontal distance D between a certain position and the laser radar 10 is determined. 1 The horizontal distance D between the front edge of the current vehicle and the laser radar 10 0 Whether the difference between them is greater than 1.3m and less than 3m;

[0034] Step S107: If the horizontal distance D between a certain position and the laser radar 10 1 The horizontal distance D between the front edge of the current vehicle and the laser radar 10 0 If the difference between them is greater than 1.3m and less than 3m, the head length HeadLen = D 1 -D 0 ;

[0035] Step S108, according to the current vehicle speed value Speed ​​obtained by the laser radar 10, the vehicle head recognition controller 30 is controlled to set the start and stop time interval of the X-ray emitting device 21 to Second = HeadLen / Speed.

[0036] In the method of this embodiment, by determining the horizontal distance D between a certain position and the laser radar 10 1 The horizontal distance D between the front edge of the current vehicle and the laser radar 10 0 Whether the difference is greater than 1.3m and less than 3m can reduce the occurrence of incorrect vehicle head recognition due to bulges on the upper part of the vehicle head or other items piled on the vehicle head, thereby effectively improving the accuracy of vehicle head recognition.

[0037] Figure 4 The present invention is a schematic diagram of a vehicle head recognition model with a container according to an embodiment of the present invention. The vehicle head has a container behind it, the container is higher than the vehicle head, and the gap between the vehicle head and the container is very small.

[0038] See also Figure 5 , the method for identifying the front of a vehicle with a container comprises the following steps:

[0039] Step S201, the system needs to detect whether there is a car in the channel.

[0040] When a vehicle is detected in the channel, the process proceeds to step S202, where each pixel of the vehicle head is scanned in sequence from the front edge of the vehicle head, and the vehicle head height h corresponding to each pixel is compared in sequence. i 、h j .

[0041] Step S203, when h j >h i If the condition is met, the process goes to step S204, indicating that the vehicle head h currently scanned j The point is the highest, and the point value is saved in the cache HeightMax.

[0042] Continue scanning the front of the vehicle, as in step S205. When the horizontal distance from the front edge of the vehicle to the vehicle body is greater than 4 meters, the radar stops the current scan.

[0043] Entering step S206, the radar performs a second round of scanning on the front of the vehicle, and reads the horizontal distance of the front pixel of the front of the vehicle again from the front edge of the vehicle: D 0 =d 0 sinθ 0 and the corresponding angle θ 0 ; Continue to read the height of the front of the vehicle in pixels: h 2 =H 0 -d 2 cosθ 2 and the corresponding angle θ 2 When h 2 If it is smaller than the highest point of the car, then continue to read the height of the next car head pixel: h i =H 0 -d i cosθ i and the corresponding angle θ i .

[0044] Step S207, when h i When approaching the highest point HeightMax of the car, θ i The dot is the front avoidance position.

[0045] Step S208, at this time, determine θ i Corresponding horizontal distance: D 1 =d i sinθ i Ratio θ 0 The corresponding horizontal distance D from the front edge of the vehicle0 When it is greater than 1.3m and less than 3m, a valid vehicle front is identified.

[0046] Step S209, calculate the head length: HeadLen = d i sinθ i -d 0 sinθ 0 .

[0047] Step S210, according to the radar speed measurement Speed, the vehicle head avoidance control system generates a vehicle head avoidance timing: Second = HeadLen / Speed. When the vehicle head just passes the ray port, the radiation imaging inspection system is controlled to scan the vehicle starting from the container, thus achieving vehicle head avoidance with containers.

[0048] Figure 6 Schematic diagram of the radar vertical angle correction triangle of the embodiment of the present invention. Since the radar cannot be installed vertically, there is always a certain deviation angle, resulting in incomplete vehicle head avoidance. Assuming that the radar is installed vertically, such as Figure 6 As shown, the radar vertical center line OC and the 60° angle lines on the left and right are OA and OB respectively. But in fact, the radar center line OC is not perpendicular to the ground, but the vertical line is OC′, and the 60° angle lines on the left and right are OA′ and OB′ respectively. In this way, OA′ and OA form a deviation angle θ, and it is necessary to calculate this deviation angle and make correction compensation. According to the Taylor series expansion, when the deviation angle θ is very small,

[0049] Then we have: sin(θ)≈θ; (1)

[0050] Difference between OA′ and OA: ΔL = L 1 -2*L 2 ; (2)

[0051] again

[0052] Substituting equations (1) and (2) into equation (3), we get

[0053]

[0054] Convert the deviation angle θ into degrees formula:

[0055] Substitute (4) into (5) to calculate the correction angle:

[0056]

[0057] From formula (6), we can see that it is only necessary to measure OA and OB by radar, that is, L 1 , L 2 , the radar deviation angle can be calculated and corrected.

[0058] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A vehicle head avoidance system based on laser radar, characterized in that: include: A laser radar (10) for collecting image data consisting of a series of polar coordinates from the radar to the inspected vehicle; A radiation imaging inspection system (20) for emitting X-rays and scanning the inspected vehicle to complete radiation imaging; and A vehicle head recognition controller (30) having an input end connected to the laser radar (10) and an output end connected to the radiation imaging inspection system (20), and used for receiving radar image data and controlling the radiation imaging inspection system (20) to emit radiation; Among them, the vehicle head recognition method based on laser radar includes: Step S101, installing a laser radar (10) based on a radar vertical angle correction algorithm; Step S102, when there is a vehicle at a preset position in the channel, the laser radar (10) obtains the distance between the installation point of the laser radar (10) and the current front end point of the vehicle head and the angle between the line from the installation point of the laser radar (10) to the current front end of the vehicle and the vertical direction , so as to calculate the horizontal distance between the front edge of the current vehicle and the laser radar (10) ; Step S103: The laser radar (10) scans along the front contour of the vehicle and obtains pixels at a certain position, and obtains the distance between the laser radar (10) and the certain position. and the angle between the line from the installation point of the laser radar (10) to a certain position and the vertical direction , calculate the height of a certain position ; Step S104, when the height of a certain position When the height is greater than the height of the next position, the horizontal distance between a certain position and the laser radar (10) is determined. The horizontal distance between the front edge of the current vehicle and the laser radar (10) Whether the difference between is greater than a first preset value and less than a second preset value; Step S105, if the horizontal distance between a certain position and the laser radar (10) The horizontal distance between the front edge of the current vehicle and the laser radar (10) If the difference between the two is greater than the first preset value and less than the second preset value, the head length is calculated. ; Among them, the radar vertical center line OC and the left and right 60° angle lines are OA and OB respectively. However, in fact, the radar center line OC is not perpendicular to the ground, but the vertical line is OC', and the left and right 60° angle lines are OA' and OB' respectively. In this way, OA' forms a deviation angle with OA , according to Taylor series expansion, we have: ; Calculate the corrected deflection angle as: ; from It can be seen that as long as the radar measures OA and OC, that is , the radar deviation angle can be calculated and corrected.

2. The laser radar-based vehicle head avoidance system according to claim 1, characterized in that: The radiation imaging inspection system (20) comprises an X-ray emitting device (21) and an imaging detector (22) connected to the X-ray emitting device, wherein the X-ray emitting device (21) is used to emit X-rays, and the imaging detector (22) is used to scan the inspected vehicle and complete radiation imaging.

3. The vehicle head avoidance system based on laser radar according to claim 2, characterized in that: The vehicle head recognition controller (30) is fixedly mounted in the X-ray emitting device (21) and connected to the X-ray emitting device (21).

4. The vehicle head avoidance system based on laser radar according to claim 1, characterized in that: After step S105, the method further comprises: obtaining the current vehicle speed value according to the laser radar (10); , controlling the vehicle head recognition controller (30) to set the start and stop time interval of the X-ray emission device (21) .

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