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robofit / but_velodyne

ROS packages for Velodyne 3D LIDARs provided by Robo@FIT group.
GNU Lesser General Public License v3.0
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data accuary problem #19

Open sakurazhu opened 7 years ago

sakurazhu commented 7 years ago 
hi ,after reading your paper and code , there is little thing about how to change .pcap to .pcd . when i did my work ,i use rosbag (https://github.com/ros-drivers/velodyne ) to change the data format,because the data i got from velodyne 16 is .pcap format. 
But when i changed the format ,i found that the accuracy of the data has decrease for example the data in .pcap is 2.0909876583 but in .pcd is 2.0909 . i have tried to change the type of the points from float to double ,but the result seemed worse .I wonder if you met the same problems ,could you please give me some suggestions .thank you very much for your kindness.
martin-velas commented 7 years ago

Hi! I have not noticed this. Actually, I can not imagine the problems, which can be caused by this "lost" of precision. The difference between 2.0909876583 (meters) and 2.0909m is actually smaller than 0.1mm. This seems to be quite insignificant comparing for example to the magnitude of common noise (~2cm) of this sensor caused by mechanical properties. So I think you do not need to deal with these differences in precision. Unfortunately this is the only advice I'm able to give you.