操作步骤：

  1. 将`learning_node/node_object.py`代码中的图片路径，修改为实际路径，`image=cv2.imread('/home/wjh/dev_ws/src/ros2_21_tutorials/learning_node/learning_node/apple.jpg')`）
  2. 修改后保存文件 重新编译-工作空间下colcon build运行
  3. ros2 run learning_node node_object

报错：

INFO] [1706020760.276750951] [node_object]: ROS2节点示例：检测图片中的苹果


Traceback (most recent call last):


  File "/home/wjh/dev_ws/install/learning_node/lib/learning_node/node_object", line 33, in <module>


    sys.exit(load_entry_point('learning-node==0.0.0', 'console_scripts', 'node_object')())


  File "/home/wjh/dev_ws/install/learning_node/lib/python3.10/site-packages/learning_node/node_object.py", line 42, in main


    object_detect(image)                                                            # 苹果检测


  File "/home/wjh/dev_ws/install/learning_node/lib/python3.10/site-packages/learning_node/node_object.py", line 19, in object_detect


    hsv_img = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)                               # 图像从BGR颜色模型转换为HSV模型


cv2.error: OpenCV(4.5.4) ./modules/imgproc/src/color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cvtColor'


[ros2run]: Process exited with failure 1