阅读说明：本技术 一种基于激光点云的飞机泊位引导方法 (Airplane berth guiding method based on laser point cloud ) 是由 顾昕 严璐 刘科岢 刘磊 于 2019-09-12 设计创作，主要内容包括：本发明公开了一种基于激光点云的飞机泊位引导方法,步骤如下：多线程激光雷达获取停机位场景原始数据；将激光雷达数据解析转换为点云格式数据；对点云数据进行相关点云预处理得到检测区域数据；在检测区域使用点云目标检测算法捕获目标飞机；对目标飞机使用点云目标跟踪算法跟踪目标运动状态；对目标飞机使用点云特征提取算法获得飞机关键特征；将提取的飞机关键特征参数与数据库中特征数据进行匹配识别出目标的机型。本发明通过设计的算法,能适应实际的机场泊位应用场景,可快速、准确、稳定地实现飞机泊位引导功能。(The invention discloses an aircraft berth guiding method based on laser point cloud, which comprises the following steps: obtaining original data of a parking space scene by a multi-thread laser radar; analyzing and converting the laser radar data into point cloud format data; carrying out related point cloud preprocessing on the point cloud data to obtain detection area data; capturing a target airplane in a detection area by using a point cloud target detection algorithm; tracking the motion state of a target by using a point cloud target tracking algorithm for the target airplane; obtaining airplane key features by using a point cloud feature extraction algorithm on a target airplane; and matching the extracted key characteristic parameters of the airplane with the characteristic data in the database to identify the model of the target. The invention can adapt to the actual airport berth application scene through the designed algorithm, and can quickly, accurately and stably realize the airplane berth guiding function.)

1. an aircraft berth guiding method based on laser point cloud is characterized by comprising the following steps:

1) acquiring original data of a parking place scene;

2) converting the obtained original data into point cloud format data;

3) Performing point cloud preprocessing on the point cloud format data to obtain point cloud data of a detection area;

4) capturing a target airplane in a detection area by using a point cloud target detection algorithm;

5) Tracking the motion state of a target by using a point cloud target tracking algorithm for the target airplane;

6) obtaining airplane key features by using a point cloud feature extraction algorithm on a target airplane;

7) And matching the extracted key features of the airplane with feature data in a database to identify the model of the target.

2. the laser point cloud-based airplane berthing guidance method according to claim 1, wherein the step 3) specifically comprises:

31) processing the point cloud format data by using a straight-through filtering algorithm to filter out a machine stop detection area;

32) And filtering ground point cloud format data of the detection area by using a plane segmentation algorithm.

3. the laser point cloud-based airplane berthing guidance method according to claim 1, wherein the step 4) specifically comprises:

41) processing and filtering the ground detection area point cloud data by using a clustering algorithm to obtain various point cloud objects;

42) extracting the characteristics of various clustered point cloud objects, and screening out a nose area of a target airplane according to set airplane nose characteristics;

43) and searching nose points of a nose area, and directly filtering and capturing the target airplane by combining the prior information of the length of the airplane body of the target airplane type.

4. the laser point cloud-based airplane berthing guidance method according to claim 1, wherein the step 5) specifically comprises: and searching the aircraft nose position based on the Kdtree according to the aircraft nose area center coordinate of the target aircraft in the previous frame, and outputting and tracking the aircraft nose area information of the current frame of the aircraft.

5. the laser point cloud-based airplane berthing guidance method according to claim 1, wherein the step 6) specifically comprises:

61) searching the relevant extreme points of the aircraft point cloud data by utilizing the inherent geometric features of the aircraft wing span to calculate the wing span length;

62) And detecting left and right engine information of the target airplane by using a point cloud segmentation algorithm in combination with the constraint of the nose area on the engine position.

Technical Field

The invention belongs to the technical field of laser radar object detection, identification and measurement, and particularly relates to an airplane berth guiding method based on laser point cloud aiming at target airplane detection and tracking in berths.

background

The system monitors the pose and speed information of the airplane approaching the berth through a laser or video sensor, displays the pose, speed and other information of the airplane through a display device in front of the berth, and can effectively guide aircrafts of different types to different stop lines to be accurately butted with a boarding bridge. Meanwhile, the integrated platform is connected with an airport data integrated platform, so that the contents of azimuth guidance, model parameters, flight information, taxi speed, flight position signals and the like of a docking airplane can be provided in real time, and the equipment level, the operation efficiency, the management level and the service quality of an airport are effectively improved.

At present, the following schemes are mostly adopted to realize the berth guiding technology:

the method is based on coil induction for guiding, and the position of the airplane is sensed by embedding an induction coil in the airport, so that the method is low in precision and easy to be interfered by external electromagnetic interference;

the method is characterized in that guidance is performed based on video shooting, the airplane is detected through video images, and the moving direction of the airplane is tracked, so that airplane guidance is realized, and the identification precision of the scheme under the conditions of poor positioning precision, poor illumination and the like is yet to be improved;

The method is characterized in that the method is guided by three-dimensional laser scanning based on double galvanometers, and the 3D scanning of the in-position airplane is realized by driving a stepping motor to control the galvanometers in the horizontal and vertical directions, so that the airplane is captured and identified and guided, and the scheme has high precision but the environmental adaptability is still to be enhanced.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an aircraft berth guiding method based on laser point cloud so as to solve the problems that the identification precision of a berth guiding technology is not high enough and the environmental adaptability is not strong enough in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

The invention relates to an aircraft berth guiding method based on laser point cloud, which comprises the following steps:

1) Acquiring original data of a parking place scene;

2) Converting the obtained original data into point cloud format data;

3) Performing point cloud preprocessing on the point cloud format data to obtain point cloud data of a detection area;

4) Capturing a target airplane in a detection area by using a point cloud target detection algorithm;

5) tracking the motion state of a target by using a point cloud target tracking algorithm for the target airplane;

6) Obtaining airplane key features by using a point cloud feature extraction algorithm on a target airplane;

7) and matching the extracted key features of the airplane with feature data in a database to identify the model of the target.

further, the step 3) specifically includes:

31) processing the point cloud format data by using a straight-through filtering algorithm to filter out a machine stop detection area;

32) and filtering ground point cloud format data of the detection area by using a plane segmentation algorithm.

Further, the step 4) specifically includes:

41) Processing and filtering the ground detection area point cloud data by using a clustering algorithm to obtain various point cloud objects;

42) Extracting the characteristics of various clustered point cloud objects, and screening out a nose area of a target airplane according to set airplane nose characteristics;

43) and searching nose points of a nose area, and directly filtering and capturing the target airplane by combining the prior information of the length of the airplane body of the target airplane type.

further, the step 5) specifically includes: and searching the aircraft nose position based on the Kdtree according to the aircraft nose area center coordinate of the target aircraft in the previous frame, and outputting and tracking the aircraft nose area information of the current frame of the aircraft.

further, the step 6) specifically includes:

61) Searching the relevant extreme points of the aircraft point cloud data by utilizing the inherent geometric features of the aircraft wing span to calculate the wing span length;

62) and detecting left and right engine information of the target airplane by using a point cloud segmentation algorithm in combination with the constraint of the nose area on the engine position.

The invention has the beneficial effects that:

(1) the invention enhances the environmental adaptability of the application scene of airplane berth guidance, designs and uses the multi-thread laser radar as the front-end perception of the berth guidance, and ensures that the system can acquire relatively clear scene data under various environmental conditions (temperature change, sunlight irradiation, darkness or rain and snow weather).

(2) The method improves the robustness of airplane berth guiding airplane detection, uses cluster detection combined with Kd-Tree search to assist tracking, and ensures that the target airplane is always stably and accurately detected.

(3) The invention enhances the applicability of airplane berth guidance, and the multithreading laser radar acquires more data information and combines with a stable point cloud detection algorithm, thereby realizing the functions of airplane berth obstacle detection and the like and improving the safety and the expansibility of berth guidance.

drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2a is a diagram illustrating the effect of a parking scene before point cloud preprocessing in the present invention;

FIG. 2b is a diagram illustrating the effect of the parking scene after the point cloud is preprocessed in the present invention;

FIG. 3 is a diagram illustrating a target aircraft detection feature result in accordance with the present invention.

Detailed Description

in order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.

referring to fig. 1, the method for guiding the berthage of the airplane based on the laser point cloud of the present invention includes the following steps:

s1, obtaining original data of the parking lot scene by the aid of the multi-thread laser radar, adjusting the pitching angle of the laser radar according to the erection height of the laser radar, and ensuring that the target airplane is in a laser scanning dense area to obtain clear laser data;

step S2, analyzing and converting original data acquired by the laser radar into point cloud format data, analyzing a UDP (user Datagram protocol) data packet of the multi-thread laser radar by using a libpcap and combining a specific calibration file, and acquiring spatial positions corresponding to all laser ranging threads to obtain real-time laser radar ranging point cloud data;

and step S3, performing related point cloud preprocessing on the point cloud format data to obtain detection area data, limiting a detection area by using a point cloud preprocessing algorithm, simplifying data, reducing interference and improving the subsequent detection processing speed. The pretreatment effect is shown in fig. 2a and fig. 2b, and the pretreatment process comprises the following steps:

S31, processing the point cloud format data by using a straight-through filtering algorithm to filter out a parking space detection area, setting area coordinate points according to the size of a parking space, the layout of the parking space and the like, and limiting and cutting out the point cloud data of the detection area;

s32, filtering ground point cloud data of the detection area by using a plane segmentation algorithm, performing plane fitting on the point cloud data of the detection area based on RANSAC, filtering plane data, and segmenting and retaining point cloud object data above a plane.

The straight-through filtering algorithm used in the step 3 is a common algorithm in the field of point cloud processing, the algorithm is realized based on a PCL (personal computer) library, the PCL library is an open source software library and complies with a BSD (base station discovery) protocol, specific technical principles are not repeated, and specifically, the method is realized by manually setting coordinate points of a detection area according to actual conditions of the machine position size, the machine position layout and the like of a berth scene, and filtering out simplified point cloud data of the detection area according to the coordinate points.

S4, capturing the target airplane in the detection area by using a point cloud target detection algorithm, wherein the method comprises the following steps:

s41, processing the ground-filtered point cloud data of the detection area by using a clustering algorithm to obtain various point cloud objects, and clustering various objects from the disordered point cloud by setting parameters such as a proper distance threshold, a maximum point number required by clustering, a minimum point number and the like through an Euclidean clustering segmentation algorithm based on Euclidean distance;

S42, extracting the geometric characteristics of the various clustered point cloud objects, and comparing the geometric characteristics with the set aircraft nose geometric characteristics to screen out the nose area of the target aircraft;

S43, according to the geometrical characteristic that the nose is in line with the nearest distance of the laser radar on the nose area, the nose area is searched in a sequencing mode, the centroid of the nose area is calculated to serve as a stable nose point, and the nose point coordinates are combined with the prior information of the length of the body of the target airplane to directly filter and capture the target airplane.

the Euclidean clustering algorithm is a common algorithm in the field of point cloud processing, and particularly, the method is realized by analyzing actual scene data and obtaining relevant and stable algorithm parameters through multiple experiments according to erection height, pitch angle and the like of the laser radar.

s5, tracking the motion state of the target by using a point cloud target tracking algorithm, searching the aircraft nose position based on Kdtree according to the aircraft nose area center coordinate of the previous frame of target aircraft, outputting and tracking the aircraft nose area information of the current frame of aircraft, and adaptively setting the value of the search radius according to the aircraft nose area width of the target aircraft in combination with the detected real-time speed of the aircraft, wherein the method comprises the following steps:

if the target airplane is tracked in the previous frame or the tracking duration is less than 2S, starting a step S5 to track the airplane movement state; if the target aircraft is not detected and tracked in the previous frame and the target loss duration exceeds 2S, step S4 is started to cluster the detected target aircraft again.

S6, obtaining airplane key features by using a point cloud feature extraction algorithm for the target airplane, wherein the feature extraction result is shown in figure 3, and the extraction process comprises the following steps:

s61, searching the relevant extreme points of the airplane point cloud data by utilizing the inherent geometric features of the airplane wing span to calculate the wing span length;

s62, detecting left and right engine information of the target airplane by using a point cloud segmentation algorithm in combination with constraint of the engine position by the nose area, namely the center distance between the left and right engines, filtering out left and right engine detection spaces according to the inherent appearance geometric characteristics of the target airplane type in combination with the detected and tracked nose position, performing space circle fitting on point cloud data in a limited space based on RANSAC, segmenting out left and right space circle models, and extracting circle center space coordinates to calculate the engine distance of the target airplane.

s7, matching the extracted key features with feature data in a database to identify the model of the target; the method specifically comprises the following steps: and calculating the similarity between the extracted engine spacing and the extracted wingspan parameters and the corresponding characteristic parameters of each model in the database, and outputting the model with the highest similarity as the identified model.

the database is a characteristic database which integrates all standard parameters of various types and model parameters which can be detected by a laser radar, analyzes the characteristics with good distinctiveness and strong stability by comparison, and summarizes and arranges the characteristics.

while the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.