Soowon's profile - activity

Hello, I am a complete freshman on Linux, ROS so, don't be mad :). I have a Velodyne VLP16 and the list that I want to with this laser is:

1. Acquire raw data (.pcap)
2. Visualize it using 3D viewer
3. Extract XYZ and Intensity data from acquired raw data

What I accomplished so far is only No.2 using commands below (I downloaded .pcap file from velodyne website):

$ roslaunch velodyne_pointcloud VPL16_points.launch pcap:=/home/soowon/Documents/County_Fair.pcap

$ rosrun velodyne_pointcloud cloud_node _calibration:=/home/soowon/catkin_ws/src/velodyne-master/velodyne_pointcloud/params/VLP16db.yaml

$ rosrun rviz rviz -f velodyne

$ Add -> By topic -> /velodyne_points -> PointCloud2

By commands above, I was able to see pointcloud using RViz. Now here's my questions:

1. I followed tutorial ( http://wiki.ros.org/velodyne/Tutorial... ) to establish connection using command below,

   $ sudo ifconfig eth0 192.168.3.100

   $ sudo route add 192.168.XX.YY eth0

however, according to wireshark, connection wasn't established at all.

1. Now I can see (gladly) the pointcloud, I really want to extract X,Y, and Z coordinates with intensity from .pcap file. I found some great sources to start ( https://github.com/PointCloudLibrary/pcl ), but I am not sure whether I can pull this off by myself :(

Any advice would be superb!! Thank you :)

Also, it still shows that I have No tf data. Does it matter? And the duration of the data is longer than 200 seconds, so I am pretty sure that I didn't miss the data while trying to figure out tf data. Would you explain me how to set a fixed frame with respect to the center of the laser? Thanks :)

Thanks! It really help me! Now I can see point cloud on RViz. But now, it flickers so many times as if the data is interpreted in a wrong way. This data is given from the velodyne website, so I am sure that the data is not corrupted.

Thank you for helping me :). I tried rosrun rviz rviz -f velodyne, as described in the ros tutorial, however, still I could not see any data from the view. In rviz, it says No tf data. Actual error: Fixed Frame [velodyne] does not exist Can you give me help on this?

Hi all, I am new on ROS and Linux. I am trying to display point cloud using rviz with VLP-16. Before starting to see real time data, I wanted to see how pcap file can be converted into human-readable, and visible data. So I used pcap file (downloaded from www.velodynelidar.com ) to convert to bag file as follows:

$ rosrun velodyne_driver velodyne_node _mol:=VLP16 _pcap:=/home/soowon/Documents/County_Fair.pcap _read_once:=true

On new terminal, to record pcap data into bag file:

$ rosrun rosbag record -O Countyfair.bag /velodyne_packets

ON new terminal, I used rosbag to play bag file that I just made:

$ rosbag play Countyfair.bag

Another new terminal, to open rviz:

$ rosrun rviz rviz

Problem starts from here.

1. I cannot see anything on the screen, even though I added PointCloud, PointCloud2. In rviz, it says "No tf data. Actual error: Fixed Frame [map] does not exist."
2. Not only that I want to see point cloud in rviz, my ultimate goal is acquiring xyz coordinates for each frame. Can you guys tell me where can I find this data?

Any advice? I would appreciate :)