approx_time_msg_extract

ROS message extraction and publisher with approximate time synchronization.

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How to compile to get a ROS package in place

First, follow this tutorial: http://wiki.ros.org/ROS/Tutorials/catkin/CreatingPackage

You should have your catkin workspace similar like this:

catkin_ws

├── devel

├── build

└── src

      └── approx_time_msg_extract     <= this repository

Then,

cd catkin_ws

catkin_make

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How to run the script?

1. Start roscore.

   roscore

2. Play back a .bag file.

   rosbag play foo.bag

3. In yet another terminal, start recording on certain messages we care.

   rosbag record /fwd_center_camera /fwd_steering_rpt /fwd_wheel_speed_rpt

4. Launch the message extract (with approximate time synchronization) and forward script.

   rosrun approx_time_msg_extract approx_time_msg.py

If everything works fine, using > rqt_graph should show a connect diagram like below.

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Convert the time-sync'ed .bag file to PyTables hdf5 file

This bag2hdf5.py script is stand-alone, not required to be part of this ROS package. But it is very specifically written to extract the "/fwd_center_camera /fwd_steering_rpt /fwd_wheel_speed_rpt" topics though.

python bag2hdf5.py file.bag