ubutu下ros2实现小车仿真建模与目标检测

1.安装ros2

这里使用小鱼的一键安装，根据自己的喜好安装，博主用的是ros2的foxy版本

wget http://fishros.com/install -O fishros && . fishros 

2.下载代码（这里使用的是古月居的代码）

https://book.guyuehome.com/

可以结合古月居的B站视频来自己一步一步操作，里面有讲解基础理论与一些环境的配置

https://www.bilibili.com/video/BV16B4y1Q7jQ?p=1&vd_source=7ab152ebd2f75f63466b8dc7d78d3cf2

3.下载yolov5的代码

https://github.com/fishros/yolov5_ros2/tree/main

将古月居下载的代码与yolov5的代码一起放入一个文件夹下

4.打开终端安装依赖

sudo apt update
sudo apt install python3-pip ros-<ros2-distro>-vision-msgs # <ros2-distro>替换为humble，foxy或galactic等ros2发行版
pip3 install -i https://pypi.tuna.tsinghua.edu.cn/simple yolov5

注：如果pip3的安装命令出现报错如下：

 这里就代表下载torch时网速慢，需要换源下载，这里我用的是去下载了torch的离线包自己进行安装https://download.pytorch.org/whl/cu116，下载安装包之前自己要先安装cuda

 进入torch后使用Ctrl+f进行搜索，cuda对应的torch版本和你的python版本,一键安装ros2的时候会下载一个python2与python3，在终端输入python3就会得到python的版本

从网上自己搜索torch对应版本的torchvision版本

 在这里右键打开终端进行安装，torchvision同理，要学会常用tab建去补全命令

 然后重新下载依赖

pip3 install -i https://pypi.tuna.tsinghua.edu.cn/simple yolov5

5.修改下载的yolov5_ros2下的yolo_detect_2d.py代码

from math import frexp
from traceback import print_tb
from torch import imag
from yolov5 import YOLOv5
import rclpy
from rclpy.node import Node
from ament_index_python.packages import get_package_share_directory
from rcl_interfaces.msg import ParameterDescriptor

from vision_msgs.msg import Detection2DArray, ObjectHypothesisWithPose, Detection2D
from sensor_msgs.msg import Image, CameraInfo
from cv_bridge import CvBridge
import cv2
import yaml

from yolov5_ros2.cv_tool import px2xy

package_share_directory = get_package_share_directory('yolov5_ros2')
# package_share_directory = "/home/mouse/code/github/yolov
# 
# 5_test/src/yolov5_ros2"


class YoloV5Ros2(Node):
    def __init__(self):
        super().__init__('yolov5_ros2')
        self.declare_parameter("device", "cuda", ParameterDescriptor(
            name="device", description="calculate_device default:cpu optional:cuda:0"))

        self.declare_parameter("model", "yolov5s", ParameterDescriptor(
            name="model", description="default: yolov5s.pt"))

        self.declare_parameter("image_topic", "/image_raw", ParameterDescriptor(
            name="image_topic", description=f"default: /image_raw"))
        # /camera/image_raw

        self.declare_parameter("camera_info_topic", "/camera/camera_info", ParameterDescriptor(
            name="camera_info_topic", description=f"default: /camera/camera_info"))

        # 默认从camera_info中读取参数,如果可以从话题接收到参数则覆盖文件中的参数
        self.declare_parameter("camera_info_file", f"{package_share_directory}/config/camera_info.yaml", ParameterDescriptor(
            name="camera_info", description=f"{package_share_directory}/config/camera_info.yaml"))

        # 默认显示识别结果
        self.declare_parameter("show_result", True, ParameterDescriptor(
            name="show_result", description=f"default: True"))

        # 1.load model
        model_path = package_share_directory + "/config/" + self.get_parameter('model').value + ".pt"
        device = self.get_parameter('device').value
        self.yolov5 = YOLOv5(model_path=model_path, device=device)

        # 2.create publisher
        self.yolo_result_pub = self.create_publisher(
            Detection2DArray, "yolo_result", 10)
        self.result_msg = Detection2DArray()

        # 3.create sub image (if 3d, sub depth, if 2d load camera info)
        image_topic = self.get_parameter('image_topic').value
        self.image_sub = self.create_subscription(
            Image, image_topic, self.image_callback, 10)

        camera_info_topic = self.get_parameter('camera_info_topic').value
        self.camera_info_sub = self.create_subscription(
            CameraInfo, camera_info_topic, self.camera_info_callback, 1)

        # get camera info
        with open(self.get_parameter('camera_info_file').value) as f:
            self.camera_info = yaml.full_load(f.read())
            print(self.camera_info['k'], self.camera_info['d'])

        # 4.convert cv2 (cvbridge)
        self.bridge = CvBridge()

        self.show_result = self.get_parameter('show_result').value

    def camera_info_callback(self, msg: CameraInfo):
        """
        通过回调函数获取到相机的参数信息
        """
        self.camera_info['k'] = msg.k
        self.camera_info['p'] = msg.p
        self.camera_info['d'] = msg.d
        self.camera_info['r'] = msg.r
        self.camera_info['roi'] = msg.roi

        self.camera_info_sub.destroy()

    def image_callback(self, msg: Image):

        # 5.detect pub result
        image = self.bridge.imgmsg_to_cv2(msg)
        detect_result = self.yolov5.predict(image)
        self.get_logger().info(str(detect_result))

        self.result_msg.detections.clear()
        self.result_msg.header.frame_id = "camera"
        self.result_msg.header.stamp = self.get_clock().now().to_msg()

        # parse results
        predictions = detect_result.pred[0]
        boxes = predictions[:, :4]  # x1, y1, x2, y2
        scores = predictions[:, 4]
        categories = predictions[:, 5]

        for index in range(len(categories)):
            name = detect_result.names[int(categories[index])]
            detection2d = Detection2D()
            detection2d.tracking_id = name
            # detection2d.bbox
            x1, y1, x2, y2 = boxes[index]
            x1 = int(x1)
            y1 = int(y1)
            x2 = int(x2)
            y2 = int(y2)
            center_x = (x1+x2)/2.0
            center_y = (y1+y2)/2.0

            # detection2d.bbox.center.position.x = center_x
            # detection2d.bbox.center.position.y = center_y
            
            # galactic使用如下center坐标，否则会报错：Pose2D object has no attribute position
            # 其它版本未验证
            # 参考http://docs.ros.org/en/api/vision_msgs/html/msg/BoundingBox2D.html 及 http://docs.ros.org/en/api/geometry_msgs/html/msg/Pose2D.html
            detection2d.bbox.center.x = center_x
            detection2d.bbox.center.y = center_y

            detection2d.bbox.size_x = float(x2-x1)
            detection2d.bbox.size_y = float(y2-y1)

            obj_pose = ObjectHypothesisWithPose()
            obj_pose.id = name
            obj_pose.score = float(scores[index])

            # px2xy
            world_x, world_y = px2xy(
                [center_x, center_y], self.camera_info["k"], self.camera_info["d"], 1)
            obj_pose.pose.pose.position.x = world_x
            obj_pose.pose.pose.position.y = world_y
            # obj_pose.pose.pose.position.z = 1.0  #2D相机则显示,归一化后的结果,用户用时自行乘上深度z获取正确xy
            detection2d.results.append(obj_pose)
            self.result_msg.detections.append(detection2d)

            # draw
            if self.show_result:
                cv2.rectangle(image, (x1, y1), (x2, y2), (0, 255, 0), 2)
                cv2.putText(image, name, (x1, y1),
                            cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 255, 0), 1)
                cv2.imshow('result', image)
                cv2.waitKey(1)

        # if view or pub
        if self.show_result:
            cv2.imshow('result', image)
            cv2.waitKey(1)

        print("before publish out if")
        if len(categories) > 0:
            self.yolo_result_pub.publish(self.result_msg)

def main():
    rclpy.init()
    rclpy.spin(YoloV5Ros2())
    rclpy.shutdown()


if __name__ == "__main__":
    main()

6.编译工作空间

 在src外打开终端进行编译

colcon build

使用colcon build进行编译src文件夹下的代码

 搜寻本地编译

source install/local_setup.bash

如果想随时随地使用，打开主目录，使用ctrl+h打开隐藏文件找到.bashrc文件打开，插入一行

7.运行仿真建模

ros2 launch learning_gazebo load_mbot_camera_into_gazebo.launch.py

 开启另一个终端

ros2 run yolov5_ros2 yolo_detect_2d --ros-args -p device:=cpu -p image_topic:=/camera/image_raw

注：image_topic:=后是相机发布的话题名，将话题名改为相机所发布的话题名一致就能实现目标检测了，效果如下

 可以通过开启另一个终端下输入以下命令实现小车的移动

ros2 run teleop_twist_keyboard teleop_twist_keyboard

 在上面终端中按i是前进，j是向左旋转视角，l是向右旋转,k是停止移动，,（逗号）为后退。

博客会不定期修改与更新，建议收藏！！！