（ROS）roslaunch usb_cam-test.launch出现错误ERROR: cannot launch node of type [image_view/image_view]:

错误：

ERROR: cannot launch node of type [image_view/image_view]: image_view
ROS path [0]=/opt/ros/melodic/share/ros
ROS path [1]=/home/ubantu/racecar_ws/src
ROS path [2]=/opt/ros/melodic/share


[ERROR] [1636359179.072371227]: Cannot identify '/dev/video0': 2, No such file or directory
[usb_cam-2] process has died [pid 3531, exit code 1, cmd /opt/ros/melodic/lib/usb_cam/usb_cam_node __name:=usb_cam __log:=/home/ubantu/.ros/log/adf22956-406b-11ec-8e9d-000c29e78502/usb_cam-2.log].
log file: /home/ubantu/.ros/log/adf22956-406b-11ec-8e9d-000c29e78502/usb_cam-2*.log

解决：

结果：再次运行roslaunch usb_cam usb_cam-test.launch可以出来