darknet run error

[ahengtell]

"roslaunch darknet_ros darknet_ros.launch roslaunch usb_cam usb_cam-test.launch"when I start darknet_ros node while cam_node is running, the darknet_ros node shows the process has died.the detail of error message is below:
Waiting for image.
Waiting for image.
[darknet_ros-2] process has died [pid 10262, exit code -11, cmd /home/aheng/桌面/ROBOTICWS/devel/lib/darknet_ros/darknet_ros camera/rgb/image_raw:=/camera/rgb/image_raw __name:=darknet_ros __log:=/home/aheng/.ros/log/d3441234-3fc8-11ed-9706-336173c45f0f/darknet_ros-2.log].
log file: /home/aheng/.ros/log/d3441234-3fc8-11ed-9706-336173c45f0f/darknet_ros-2*.log
^C[rosout-1] killing on exit
[master] killing on exit
shutting down processing monitor...
... shutting down processing monitor complete
done