点云发布（pointcloud_publisher）之ROS2案例

Posted 2021-12-04 zhangrelay

二维曲线绘制玩腻了，可以来搞一搞三维点云了，效果更棒哦。

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官方示例给出了点云发布案例效果很好。

致敬Matlab

官方原版

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源代码如下：

# Copyright 2020 Evan Flynn
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import numpy as np

import rclpy
from rclpy.node import Node
from sensor_msgs.msg import PointCloud2
from sensor_msgs.msg import PointField
from sensor_msgs_py import point_cloud2
from std_msgs.msg import Header


class PointCloudPublisher(Node):

    rate = 30
    moving = True
    width = 100
    height = 100

    header = Header()
    header.frame_id = 'map'

    dtype = PointField.FLOAT32
    point_step = 16
    fields = [PointField(name='x', offset=0, datatype=dtype, count=1),
              PointField(name='y', offset=4, datatype=dtype, count=1),
              PointField(name='z', offset=8, datatype=dtype, count=1),
              PointField(name='intensity', offset=12, datatype=dtype, count=1)]

    def __init__(self):
        super().__init__('pc_publisher')
        self.publisher_ = self.create_publisher(PointCloud2, 'test_cloud', 10)
        timer_period = 1 / self.rate
        self.timer = self.create_timer(timer_period, self.timer_callback)
        self.counter = 0

    def timer_callback(self):
        self.header.stamp = self.get_clock().now().to_msg()
        x, y = np.meshgrid(np.linspace(-2, 2, self.width), np.linspace(-2, 2, self.height))
        z = 0.5 * np.sin(2*x-self.counter/10.0) * np.sin(2*y)
        points = np.array([x, y, z, z]).reshape(4, -1).T
        pc2_msg = point_cloud2.create_cloud(self.header, self.fields, points)
        self.publisher_.publish(pc2_msg)

        if self.moving:
            self.counter += 1


def main(args=None):
    rclpy.init(args=args)
    pc_publisher = PointCloudPublisher()
    rclpy.spin(pc_publisher)
    pc_publisher.destroy_node()
    rclpy.shutdown()


if __name__ == '__main__':
    main()

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参考如上代码可以给出很多点云效果的。

z = np.sin(x)

 供参考

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z = np.sqrt(8-x*x-y*y)

供参考

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z = 0.2*y * np.sin(2*x-self.counter/10.0) + 0.2*x * np.cos(2*y+self.counter/10.0)

供参考 

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 思考题：

        r = np.sqrt(4*x*x+4*y*y)
        z = np.sin(r)/r

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致敬matlab

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-Fin-

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