Changes between Version 6 and Version 7 of Processing/LidarCalibrationProcedure

Apr 30, 2009, 3:55:55 PM (15 years ago)



  • Processing/LidarCalibrationProcedure

    v6 v7  
    8888== Range Calibration ==
    89 The second stage in the calibration process is to calibrate the range offsets.
     89The second stage in the calibration process is to calibrate the range offsets.
     91Can do range correction if the boresight results are good. This is a 2 stage process:
     93 * 1. Nominal offset determination A1
     94 * 2. Define relative differences for A2,A3,A4 and B1,B2,B3,B4
     96points have approx. the same range error within +/-7 degrees of Nadir, so we look only at this region firstly.
     98== Procedure ==
     1001. Start up ALS Post Processor
     101 * In filters dialog set the angles to +7 and -7 degrees
     102 * Change the output directory (to 02a_Roff+-7deg if using suggested directory structure)
     103 * Run the processing on the 4 low altitude flight lines.
     1052.Load the results into Terrascan and use the 30-40 GCPs of the calibration site.
     106 * Tools -> Output Control Report
     107 * Browse -> GCP file and remove bad points (maybe an error occurred in the surveying of a certain point)
     108 * Look at the dz value, the average dz is used for the nominal range offset A1.
     109 * Save the text file.
     1113. Preferably using data including areas of forest and the BIT mode data, run Rangecardcal (from ALSPP tools menu)
     112 * Enter the average dz value as A1 to get the other offsets.
     113 * Add the outputs to the ALSPP dialog and save the settings reg file (to a new name)
     1154. Analyse the results
     116 * Check these results and re-run using the full FOV (~45 degrees)
     117 * Check average dz is less than 1cm or so, and standard deviation <5cm in Terrascan control report. (also look at cross sections)
     118 * Then process the 4 high altitude flights in ALSPP and check in TerraScan (around nadir and swath edges)
     119 * Finally load in all flights into Terrascan (within a fence if memory issues) and check them (ideally along a stream because this has a “good” profile) Can use the travel path tool in Terrascan for comparing cross sections along a path.