viso2 with elas_ros

[meixialin]

hello.I am sorry to disturb you.But I cannot launch the viso2 with elas_ros successfully .I need your help.
The response as follows:
[ WARN] [1536650664.048094195, 1428920107.712918255]: The tf from '/base_link' to 'stereo_forward_optical' does not seem to be available, will assume it as identity! terminate called after throwing an instance of 'tf2::LookupException'362 what(): "stereo_forward_optical" passed to lookupTransform argument source_frame does not exist. [pc_construction-5] process has died [pid 20887, exit code -6, cmd /home/ppg/elas_ws/devel/lib/elas_ros/pc_construction frame_data:=/elas_ros/frame_data pose:=/stereo_odometer/pose base_frame_id:=/odom pose_frame_id:=/base_link __name:=pc_construction __log:=/home/ppg/.ros/log/df920058-b590-11e8-9d06-e0d55e489afd/pc_construction-5.log]. log file: /home/ppg/.ros/log/df920058-b590-11e8-9d06-e0d55e489afd/pc_construction-5*.log
I didn't have the urdf ,so I just comment it.
I would be very grateful to you if you could answer me.
Best Wishes!