CN112464994B - PointNet network-based boat tail wave recognition and removal method - Google Patents

PointNet network-based boat tail wave recognition and removal method Download PDF

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CN112464994B
CN112464994B CN202011225901.2A CN202011225901A CN112464994B CN 112464994 B CN112464994 B CN 112464994B CN 202011225901 A CN202011225901 A CN 202011225901A CN 112464994 B CN112464994 B CN 112464994B
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tail
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李清洲
刘新新
杨长坤
胡常青
刘柳
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Aerospace Times Qingdao Marine Equipment Technology Development Co ltd
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Abstract

The method for identifying and removing the stern waves of the ships and the boats based on the PointNet network comprises the following steps: s1: acquiring point cloud data of the unmanned ship in 360 degrees in real time by utilizing a laser radar; s2: denoising the point cloud data; s3: performing Euclidean distance clustering on the point cloud data subjected to denoising processing to obtain a suspicious target list; s4: constructing a PointNet deep learning model and loading trained weight parameters; s5: inputting the clustered point cloud subsets into a PointNet deep learning model for classification and identification; s6: removing the point cloud subset identified as the tail wave target from the suspicious target list; s7: judging whether each tail wave target is the tail wave generated by the unmanned ship or the tail wave generated by other ships, and positioning the ship target on the water surface according to the tail wave position under the condition of not self tail waves; s8: and sending the detection result of the water surface obstacle to the unmanned ship control platform. According to the invention, the PointNet deep learning model is utilized to realize rapid recognition and removal of the stern waves of the boat, and the target boat is positioned based on the stern wave recognition result, so that the adaptability of the laser radar to the application on the water surface is improved.

Description

PointNet network-based boat tail wave recognition and removal method
Technical Field
The invention relates to a ship stern wave recognition and removal method based on a PointNet network, and belongs to the technical field of environmental awareness.
Background
Lidar is one of the most important and indispensable sensors in the implementation of automatic driving, and its importance is self-evident, such as obstacle detection, road edge detection, map construction, etc. is not separated. The stern wave of the boat can be detected by the laser radar by reflecting the detection laser, but the stern wave does not belong to a water surface obstacle and does not influence the navigation route of the boat, so that the stern wave needs to be filtered from the targets detected by the laser radar. The tail waves generated by the unmanned ship can be determined to be positioned behind the ship, but the tail waves also change in real time along with the change of the navigation speed of the ship. The tail waves generated by the unmanned ship can be removed by filtering the point cloud in a certain range behind the ship, but the filtering range needs to be set to be far larger than the fixed range of the actual tail waves to ensure the accurate filtering of the tail waves, so that the water surface target detection capability of the unmanned ship under the close range condition is greatly reduced. The tail waves generated by the water surface target boat can improve the detection probability and the detection distance of the target, but also can improve the positioning error of the water surface target boat, thereby affecting the accurate planning of the obstacle avoidance path of the unmanned boat. Unmanned ship is urgent to obtain the detection and recognition capability of the navigation tail wave of the ship based on the laser radar, and the tail wave is accurately filtered, so that the close-range detection capability of the laser radar equipment in the water surface environment and the positioning capability of a long-range target are improved.
Disclosure of Invention
The technical solution of the invention is as follows: overcomes the defects of the prior art and provides a method for identifying and removing the stern waves of a boat based on a PointNet network.
The technical scheme of the invention is as follows:
the method for identifying and removing the stern waves of the ships and the boats based on the PointNet network comprises the following steps:
s1: the laser radar equipment is arranged at the non-shielding position at the top of the unmanned ship, and the point cloud data of the unmanned ship in the 360-degree range is acquired in real time;
s2: denoising processing based on point cloud density statistics is carried out on the current point cloud data, and discrete noise points in the point cloud data are removed;
s3: performing Euclidean distance clustering on point cloud data with noise points removed according to a pre-designed tolerance distance, dividing the point cloud data into a plurality of independent point cloud subsets, wherein each point cloud subset is a suspicious target, and counting and determining target point clouds, boundary ranges, target center points and target radiuses of each suspicious target to obtain a suspicious target list;
s4: constructing a PointNet deep learning model and loading trained weight parameters;
s5: in the S3, searching point cloud subsets with point cloud points and target radius larger than the preset data, and inputting the found point cloud subsets into a PointNet deep learning model for classification and identification;
s6: if a certain point cloud subset is identified as a tail wave target through the PointNet deep learning model, removing the point cloud subset from a suspicious target list;
s7: judging whether each tail wave target is the tail wave generated by the unmanned ship or the tail wave generated by other ships, if the tail wave generated by other ships, determining the water surface navigation ship target corresponding to the tail wave target, and forming a water surface barrier together with other suspicious targets;
s8: according to the position change of the water surface obstacle in the continuous frames, the current position, the movement speed and the movement direction of the water surface obstacle are calculated, the Kalman filtering is utilized to optimize detection information and predict the movement trend of the obstacle, and finally the information is used as a detection result to be sent to the unmanned ship control platform to assist in realizing the automatic driving and the autonomous obstacle avoidance of the unmanned ship.
In the step S2, the step of denoising the current point cloud data is as follows:
(2.1) setting the number k of neighborhood points and a standard deviation multiple threshold std_mul;
(2.2) calculating the distance average value d of each point in the current point cloud data and k field points to form a distance vector;
(2.3) estimating a distance mean mu and a standard deviation sigma in the whole point cloud data according to the distance vector, wherein the distance vector accords with Gaussian distribution;
(2.4) calculating a distance threshold value with a calculation formula of t=μ+σx std_mul; the method comprises the steps of carrying out a first treatment on the surface of the
(2.5) if the distance average d is greater than the distance threshold t, the laser detection point is an outlier and is filtered from the current point cloud data.
In the step S3, the tolerance distance is a distance threshold of the point cloud distance cluster, and if the distance between two points is smaller than the tolerance distance, the two points are considered to belong to one target, otherwise, the two points are considered to not belong to one target.
The implementation manner of the step S7 is as follows:
for each point cloud subset identified as a tail wave target, the following operations are performed:
according to the point Yun Ziji, performing shape fitting on a tail wave fan of a tail wave target, wherein the top of the fan after shape fitting is the position of the target boat which causes the tail wave, and if the position is coincident with the position of the unmanned boat, the tail wave is the tail wave generated by the unmanned boat; otherwise, the tail waves generated by other boats are used as the tail waves, the fan-shaped top is a water surface navigation boat target, and the tail waves and other suspicious targets form a water surface barrier together.
The method for performing shape fitting on the tail wave sector of the tail wave target according to the point Yun Ziji is as follows:
(5.1) randomly selecting three points A, B, C from the tail wave point cloud subset;
(5.2) taking B, C as a fixed point, searching a point farthest from B, C points from the tail wave point cloud subset, and updating the position of the point A by using the point;
(5.3) taking C, A as a fixed point, searching a point farthest from C, A points from the tail wave point cloud subset, and updating the position of the point B by using the point;
(5.4) taking A, B as a fixed point, searching a point farthest from A, B points from the tail wave point cloud subset, and updating the position of the point C by using the point;
(5.5) repeating the steps (5.2) - (5.4) until the positions of the three points A, B, C are not changed any more, and entering the step (5.6);
(5.6) A, B, C, calculating angles of three vertex angles A, B and C of the triangle, selecting a vertex corresponding to the minimum angle as a circle center, setting 1.2 times of the minimum angle as a fan-shaped angle, setting 1.2 times of the maximum distance from the vertex corresponding to the minimum angle to other two points as a radius, and constructing a fan-shaped shape, wherein the fan-shaped shape covers all tail wave point clouds.
The training process of the PointNet deep learning model is as follows:
(6.1) acquiring point cloud data in a 360-degree range of the unmanned ship by using laser radar equipment;
(6.2) manually marking the unmanned ship point cloud data with tail wave point cloud, wherein the tail wave target is marked as 1, and the non-tail wave target is marked as 0;
(6.3) combining unmanned ship point cloud data and a marking result into PointNet deep learning model training data;
(6.4) denoising processing based on point cloud density statistics is carried out on the training data;
(6.5) carrying out Euclidean distance clustering on the training data processed in the step (6.4) according to the pre-designed tolerance distance, and dividing the training data into a plurality of independent point cloud subsets;
(6.6) using the training data to accelerate training of the PointNet deep learning model on the multiple GPU servers.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, the tail wave point cloud distribution in the point cloud data is learned and identified through the PointNet deep learning model, so that the tail wave is accurately removed, the tail wave presents a fan-shaped plane distribution and is easy to identify, and the tail wave shape analysis result can also assist in positioning a water surface target boat, so that the detection capability of the laser radar is improved. The PointNet deep learning model directly utilizes point cloud data to carry out learning training, can greatly improve the recognition speed of tail waves, and is matched with the rapid scanning capability of a laser radar. The tail waves of the unmanned ship are accurately identified and removed, interference of the tail waves to the close-range water surface obstacle can be eliminated, and the close-range water surface target detection discovery capability and the adaptation capability of the unmanned ship are effectively improved.
(2) According to the method, the original laser radar data is optimized by adopting a denoising algorithm based on the point cloud density statistics, and discrete noise points of the laser radar point cloud data are filtered, so that the accuracy of a point cloud segmentation method based on distance clustering is effectively ensured.
(3) According to the method, the laser radar point cloud is rapidly segmented into mutually independent targets by utilizing a distance clustering method, and the segmentation result is transmitted to a PointNet deep learning model for classification and identification. Because of the mirror reflection effect, the calm water surface is not imaged in the laser radar data, the laser radar water surface point cloud data only comprises targets such as water surface obstacles, the laser point number is usually kept at a lower level, the distance clustering segmentation method of the point cloud can achieve extremely high speed, and the real-time performance of the method for processing the laser radar data is ensured by combining with the PointNet deep learning model.
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FIG. 1 is a flow chart of the PointNet model training data creation provided by the present invention;
FIG. 2 is a flowchart of the PointNet model training provided by the present invention;
FIG. 3 is a flow chart of tail wave detection and identification based on PointNet provided by the invention.
FIG. 4 is a diagram showing the network configuration parameters of the deep learning PointNet model according to the present invention.
Detailed Description
The technical scheme of the invention is further described in detail through the attached drawings.
The invention aims to automatically detect and identify a water surface area and an unknown water surface obstacle based on a visible light camera, and is applicable to pixel-level detection distributed in the water surface area and automatic detection of the unknown water surface obstacle. Therefore, the invention designs a deep learning PointNet model, utilizes a laser radar to detect point cloud data around the unmanned ship, utilizes statistical noise filtering to remove discrete noise in the point cloud data, utilizes a distance clustering-based method to divide the point cloud into mutually independent targets, trains the PointNet deep learning model to learn and identify tail wave point clouds generated by navigation of the ship in the point cloud data, enables the tail wave to be in fan-shaped plane distribution and easy to identify, and can filter the tail wave point clouds in the point cloud data according to the identification result. And fitting the shape of the tail wave fan according to the identification result, wherein the top of the fan is a target boat position for causing the tail wave, the tail wave generated by the unmanned boat is obtained by overlapping the position of the tail wave fan and the unmanned boat, otherwise, the tail wave generated by other boats is obtained by combining the position of the tail wave fan with other water surface targets to form a water surface barrier. The aggregation result of the water surface obstacles detected by the laser radar can guide the unmanned ship to navigate and avoid the obstacle autonomously.
As shown in FIG. 3, the method for identifying and removing the stern waves of the ships based on the PointNet network comprises the following steps:
s1: and arranging the laser radar equipment at a non-shielding position at the top of the unmanned ship, and acquiring the point cloud data of the unmanned ship within 360 degrees in real time.
S2: and denoising the current point cloud data based on the point cloud density statistics to remove discrete noise points in the point cloud data.
The denoising process comprises the following steps:
(2.1) setting the number k of neighborhood points and a standard deviation multiple threshold std_mul;
(2.2) calculating the distance average value d of each point in the current point cloud data and k field points to form a distance vector;
(2.3) estimating a distance mean mu and a standard deviation sigma in the whole point cloud data according to the distance vector, wherein the distance vector accords with Gaussian distribution;
(2.4) calculating a distance threshold value with a calculation formula of t=μ+σx std_mul;
(2.5) if the distance average d is greater than the distance threshold t, the laser detection point is an outlier and is filtered from the current point cloud data.
S3: and (3) carrying out Euclidean distance clustering on the point cloud data with noise points removed according to a pre-designed tolerance distance, dividing the point cloud data into a plurality of independent point cloud subsets, wherein each point cloud subset is a suspicious target, and counting and determining the target point cloud, the boundary range, the target center point and the target radius of each suspicious target to obtain a suspicious target list.
The tolerance distance is a distance threshold value of the point cloud distance cluster, if the distance between two points is smaller than the tolerance distance, the two points are considered to belong to one target, otherwise, the two points are considered to not belong to one target.
S4: and constructing a PointNet deep learning model and loading trained weight parameters.
S5: and in S3, searching for a point cloud subset with the point cloud point number and the target radius larger than the pre-specified data in each point cloud subset, and inputting the found point cloud subset into the PointNet deep learning model for classification and identification.
S6: if a certain point cloud subset is identified as a tail wave target through the PointNet deep learning model, the point cloud subset is removed from the suspicious target list.
S7: for each point cloud subset identified as a tail wave target, the following operations are performed:
according to the point Yun Ziji, performing shape fitting on a tail wave fan of a tail wave target, wherein the top of the fan after shape fitting is the position of the target boat which causes the tail wave, and if the position is coincident with the position of the unmanned boat, the tail wave is the tail wave generated by the unmanned boat; otherwise, the tail waves generated by other boats are used as the tail waves, the fan-shaped top is a water surface navigation boat target, and the tail waves and other suspicious targets form a water surface barrier together.
The method for performing shape fitting on the tail wave sector of the tail wave target according to the point Yun Ziji is as follows:
(5.1) randomly selecting three points A, B, C from the tail wave point cloud subset;
(5.2) taking B, C as a fixed point, searching a point farthest from B, C points from the tail wave point cloud subset, and updating the position of the point A by using the point;
(5.3) taking C, A as a fixed point, searching a point farthest from C, A points from the tail wave point cloud subset, and updating the position of the point B by using the point;
(5.4) taking A, B as a fixed point, searching a point farthest from A, B points from the tail wave point cloud subset, and updating the position of the point C by using the point;
(5.5) repeating the steps (5.2) - (5.4) until the positions of the three points A, B, C are not changed any more, and entering the step (5.6);
and (5.6) calculating angles of three vertex angles A, B and C of the triangle ABC, selecting a vertex corresponding to the minimum angle as a circle center, wherein 1.2 times of the minimum angle is a fan-shaped angle, 1.2 times of the maximum distance from the vertex corresponding to the minimum angle to other two points is a radius, and constructing a fan-shaped shape, wherein the fan-shaped shape covers all tail wave point clouds.
S8: according to the position change of the water surface obstacle in the continuous frames, the current position, the movement speed and the movement direction of the water surface obstacle are calculated, the Kalman filtering is utilized to optimize detection information and predict the movement trend of the obstacle, and finally the information is used as a detection result to be sent to the unmanned ship control platform to assist in realizing the automatic driving and the autonomous obstacle avoidance of the unmanned ship.
A PointNet deep learning model is built on a deep learning platform (TensorFlow or Pytorch), and the PointNet model can realize classification domain identification of three-dimensional point clouds, and detailed design parameters of the model are shown in fig. 4. In fig. 4, inputLayer represents an input layer, conv-bn-relu represents a convolution module, maxPooling represents a max pooling layer, dense-bn-relu represents a fully connected layer, reshape represents a data shaping layer, dropout represents a random inactivation layer, and softmax represents a classification layer.
As shown in fig. 1, training data of the PointNet deep learning model is obtained as follows:
(1) The laser radar is arranged at the high position of the mast of the unmanned ship, the situation that the equipment work is influenced by shielding of 360 degrees around the laser radar is guaranteed, and the point cloud data of the unmanned ship in the 360-degree range are acquired in real time according to a laser radar equipment protocol.
(2) Manually marking the unmanned ship point cloud data with tail wave point cloud, wherein the tail wave target is marked as 1, and the non-tail wave target is marked as 0;
(3) And forming the unmanned ship point cloud data and the marking result into point cloud data trained by a PointNet deep learning model, and storing the point cloud data to a specified path.
As shown in fig. 2, the training method of the PointNet deep learning model is as follows:
and automatically scanning all training point cloud data from the point cloud folder, randomly selecting the training point cloud data to generate model training data, wherein the model training data comprises label data corresponding to the model training data.
(1) Denoising the training data based on the point cloud density statistics;
(2) Carrying out Euclidean distance clustering on the training data after denoising treatment according to a pre-designed tolerance distance, dividing the training data into a plurality of independent subsets, wherein each subset is a suspicious target, and statistically determining a target point cloud, a boundary range, a target center point and a target radius of each suspicious target to obtain a suspicious target list;
(3) Utilizing a multi-GPU server to accelerate training of the PointNet deep learning model;
(4) And storing the trained PointNet deep learning model network structure and weight parameters, and copying the network structure and the weight parameters to an unmanned ship-borne computer for identifying tail waves and surface ships in the unmanned ship navigation process.
The invention can be executed by a shipborne environment sensing system based on laser radar equipment, and can realize rapid detection and identification of self tail waves of unmanned ships and tail waves of other ships.
Examples:
s310, installing the laser radar at the high position of the mast of the unmanned ship, and enabling the laser radar to be free of shielding within the range of 360 degrees.
And S320, the shipborne computer runs a laser radar driving program to communicate with laser radar equipment, and three-dimensional point cloud data of the unmanned ship in a 360-degree range are collected in real time.
S330, denoising processing based on point cloud density statistics is carried out on the current point cloud data, and discrete noise points in the laser radar point cloud data are removed.
S340, performing Euclidean distance clustering on the laser radar point cloud with noise removed, dividing the point cloud into a plurality of independent point cloud handwriting as suspicious targets, and further performing statistical analysis on information such as target point cloud, boundary range, target center point, target radius and the like of the suspicious targets.
S350, the shipborne computer automatically loads the trained PointNet deep learning model and weight parameters, sets the training model as an inference mode, searches for a point cloud subset with the point cloud number and the target radius larger than the pre-specified data in each point cloud subset, and inputs the found point cloud subset into the PointNet deep learning model for classification and identification; and inputting the found point cloud subset, and outputting class labels of suspicious targets on the water surface.
S360, if a certain point cloud subset is identified as a tail wave target through the PointNet deep learning model, the point cloud subset is removed from the suspicious target list.
S370, according to the point Yun Ziji, fitting the shape of the tail wave fan of the tail wave target, wherein the top of the fan is the target boat position for causing the tail wave, the position is overlapped with the position of the unmanned boat, namely the tail wave generated by the unmanned boat, otherwise, the position is the tail wave generated by other boats, and the position is a water surface navigation boat target and forms a water surface barrier together with other water surface targets.
And S380, calculating the current position, the movement speed and the movement direction of the water surface target according to the position change of the water surface target in the continuous frames, optimizing detection information and predicting the movement trend of the target by utilizing Kalman filtering, and finally counting the detection result and sending the detection result to the unmanned ship for autonomous navigation and autonomous obstacle avoidance.
According to the method, the PointNet deep learning model is utilized to realize rapid recognition and removal of the stern waves of the ship, and the target ship is positioned based on the stern wave recognition result, so that the adaptability of the laser radar equipment to the water surface application is improved.
The method can also realize the detection and identification of the non-tail wave targets on the water surface, but is limited by the lower detection resolution of the existing laser radar equipment, the laser radar can only identify the targets with larger short distance and larger size, and the targets need to acquire enough points to reflect the shape of the targets. Therefore, the method only identifies and filters tail wave targets at present, and the detection identification range of the method can be expanded to various water surface targets along with the improvement of the detection resolution of the laser radar in the future.
What is not described in detail in the present specification belongs to the known technology of those skilled in the art.

Claims (6)

1. The method for identifying and removing the stern waves of the ships and the boats based on the PointNet network is characterized by comprising the following steps of:
s1: the laser radar equipment is arranged at the non-shielding position at the top of the unmanned ship, and the point cloud data of the unmanned ship in the 360-degree range is acquired in real time;
s2: denoising processing based on point cloud density statistics is carried out on the current point cloud data, and discrete noise points in the point cloud data are removed;
s3: performing Euclidean distance clustering on point cloud data with noise points removed according to a pre-designed tolerance distance, dividing the point cloud data into a plurality of independent point cloud subsets, wherein each point cloud subset is a suspicious target, and counting and determining target point clouds, boundary ranges, target center points and target radiuses of each suspicious target to obtain a suspicious target list;
s4: constructing a PointNet deep learning model and loading trained weight parameters;
s5: in the S3, searching point cloud subsets with point cloud points and target radius larger than the preset data, and inputting the found point cloud subsets into a PointNet deep learning model for classification and identification;
s6: if a certain point cloud subset is identified as a tail wave target through the PointNet deep learning model, removing the point cloud subset from a suspicious target list;
s7: judging whether each tail wave target is the tail wave generated by the unmanned ship or the tail wave generated by other ships, if the tail wave generated by other ships, determining the water surface navigation ship target corresponding to the tail wave target, and forming a water surface barrier together with other suspicious targets;
s8: and calculating the current position, the movement speed and the movement direction of the water surface obstacle according to the position change of the water surface obstacle in the continuous frames, optimizing detection information and predicting the movement trend of the obstacle by utilizing Kalman filtering, and finally sending the obstacle information and the detection information to an unmanned ship control platform as detection results to assist in realizing the automatic driving and the autonomous obstacle avoidance of the unmanned ship.
2. The method for identifying and removing the stern waves of the ship based on the PointNet network according to claim 1, wherein in the step S2, the step of denoising the current point cloud data is as follows:
(2.1) setting the number k of neighborhood points and a standard deviation multiple threshold std_mul;
(2.2) calculating the distance average value d of each point in the current point cloud data and k field points to form a distance vector;
(2.3) estimating a distance mean mu and a standard deviation sigma in the whole point cloud data according to the distance vector, wherein the distance vector accords with Gaussian distribution;
(2.4) calculating a distance threshold value with a calculation formula of t=μ+σx std_mul;
and (2.5) if the distance average value d is greater than the distance threshold t, the laser detection point in the point cloud data corresponding to the distance average value d is an outlier point, and filtering out from the current point cloud data.
3. The method for identifying and removing stern waves of a ship based on a PointNet network according to claim 1, wherein in the step S3, the tolerance distance is a distance threshold of a point cloud distance cluster, and two points are considered to belong to one target if the distance between the two points is smaller than the tolerance distance, and are not considered to belong to one target if the distance between the two points is smaller than the tolerance distance.
4. The method for identifying and removing the stern waves of the ship based on the PointNet network according to claim 1, wherein the implementation manner of the step S7 is as follows:
for each point cloud subset identified as a tail wave target, the following operations are performed:
according to the point Yun Ziji, performing shape fitting on a tail wave fan of a tail wave target, wherein the top of the fan after shape fitting is the position of the target boat which causes the tail wave, and if the position is coincident with the position of the unmanned boat, the tail wave is the tail wave generated by the unmanned boat; otherwise, the tail waves generated by other boats are used as the tail waves, the fan-shaped top is a water surface navigation boat target, and the tail waves and other suspicious targets form a water surface barrier together.
5. The method for identifying and removing stern waves of a ship based on a PointNet network as set forth in claim 4, wherein the method for fitting the shape of the stern wave sector of the stern wave object according to the point Yun Ziji is as follows:
(5.1) randomly selecting three points A, B, C from the tail wave point cloud subset;
(5.2) taking B, C as a fixed point, searching a point farthest from B, C points from the tail wave point cloud subset, and updating the position of the point A by using the point;
(5.3) taking C, A as a fixed point, searching a point farthest from C, A points from the tail wave point cloud subset, and updating the position of the point B by using the point;
(5.4) taking A, B as a fixed point, searching a point farthest from A, B points from the tail wave point cloud subset, and updating the position of the point C by using the point;
(5.5) repeating the steps (5.2) - (5.4) until the positions of the three points A, B, C are not changed any more, and entering the step (5.6);
(5.6) A, B, C, calculating angles of three vertex angles A, B and C of the triangle, selecting a vertex corresponding to the minimum angle as a circle center, setting 1.2 times of the minimum angle as a fan-shaped angle, setting 1.2 times of the maximum distance from the vertex corresponding to the minimum angle to other two points as a radius, and constructing a fan-shaped shape, wherein the fan-shaped shape covers all tail wave point clouds.
6. The method for identifying and removing the stern waves of the ship based on the PointNet network according to claim 1, wherein the training process of the PointNet deep learning model is as follows:
(6.1) acquiring point cloud data in a 360-degree range of the unmanned ship by using laser radar equipment;
(6.2) manually marking the unmanned ship point cloud data with tail wave point cloud, wherein the tail wave target is marked as 1, and the non-tail wave target is marked as 0;
(6.3) combining unmanned ship point cloud data and a marking result into PointNet deep learning model training data;
(6.4) denoising processing based on point cloud density statistics is carried out on the training data;
(6.5) carrying out Euclidean distance clustering on the training data processed in the step (6.4) according to the pre-designed tolerance distance, and dividing the training data into a plurality of independent point cloud subsets;
(6.6) using the training data to accelerate training of the PointNet deep learning model on the multiple GPU servers.
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