谢谢各路大神的博客指引。本人写这篇博客是为自己的学习做标记，也希望后来者少走弯路。
$ cd ~/catkin_ws/src
$ git clone https://github.com/bosch-ros-pkg/usb_cam.git
$ cd ~/catkin_ws
$ catkin_make
$ source ~/catkin_ws/devel/setup.bash roscd usb_cam
rosrun usb_cam usb_cam_node
rosrun image_view image_view image:=/usb_cam/image_raw