'select timeout' when running 'usb_cam_node' [closed]

edit

I planned to rerun the ORB_SLAM2 open codes using TUM database on my PC. I have finished all installation of dependdencies and downloaded all codes we need to used in this process,

then

cd ~/orbslam_ws
source devel/setup.bash
roslaunch usb_cam usb_cam-test.launch

error message:

[ERROR] [1526278532.672410250]: select timeout
[camera-1] process has died [pid 103266, exit code 1, cmd /home/htf/orbslam_ws/devel/lib/usb_cam/usb_cam_node /usb_cam/image_raw:=/camera/image_raw __name:=camera __log:=/home/htf/.ros/log/78bb35ae-573d-11e8-a5a9-000c291bb522/camera-1.log].
log file: /home/htf/.ros/log/78bb35ae-573d-11e8-a5a9-000c291bb522/camera-1*.log

these disgusting errors were displayed on the terminal. I am just a naive beginner of SLAM and ROS, Does anyone could help me to solve this problem ? thank you very much.