Changes between Version 22 and Version 23 of Sensors/LeicaLIDAR/MikesNotes


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Timestamp:
Sep 5, 2008 3:44:50 PM (10 years ago)
Author:
mggr
Comment:

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  • Sensors/LeicaLIDAR/MikesNotes

    v22 v23  
    1 == todo ==
    2 
    3 
    4 
    51== Mirror torsion error correction ==
    62
    73This shouldn't need to be done with newer LIDARs, but included here in case.  Leica suggests checking for torsion errors if there seem to be problems in the boresight calibration and reporting to them if found.
    84
    9 TBD
     5Visible sign of torsion error is a smile effect.
     6
     7Detect torsion by:
     8 * choose highest altitude pair of crossing lines
     9 * pick a point at nadir on one swath and at the edge on the other
     10   * torsion will be at max for the edge swath and at 0 for the nadir swath
     11 * take cross sections to see if there is any consistent vertical difference
    1012
    1113== Ground classification ==
     
    1517Steps:
    1618 * remove very low, noisy points from consideration first
    17    * e.g. remove groups of up to 3 points > 1m below neighbours (iterate a time or two so it settles)
    18 
    19 
     19   * e.g. remove groups of up to 3 points > 1m below neighbours (iterate a few times so it settles)
     20 * classify groups of low points as ground (run N times to settle), takes account of neighbours
     21 * repeat with singletons
     22 * remove isolated points (>5m from any other point)
     23 * manually "add points to ground" for areas that should be ground but haven't been classified as such (e.g. peaks of hills) and rerun process above
     24
     25Run as a macro.  Terra->tools->macro->new.
    2026
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