Changes between Version 22 and Version 23 of Processing/LidarCalibrationProcedure

Aug 1, 2012 3:14:13 PM (7 years ago)



  • Processing/LidarCalibrationProcedure

    v22 v23  
    31312. In ALS Post Processor:
    32  * uncheck the “average last returns” option in the settings dialog
     32 * Load up the calibrated reg file (received from Leica) to get correct scanner settings
    3333 * Check the output as attune files in the outputs dialog
    3434 * Add all the flight data into the ALSPP, including the BIT mode data.
    3535 * Run the Rangecardcal program from the utilities menu.  Select the use all SCN files option when prompted.
    36    * Enter range offset A1 as 0 since it is unknown#
    37    * Enter the output Range offsets into the range corrections dialog of ALSPP. R1 for A and B should be zero.
     36   * Enter range offset A1 as 0 since it is unknown (if a good Range card value is known it should be used instead of zero)
     37   * Enter the output Range offsets into the range corrections dialog of ALSPP.
     38 * Run Compute Scanner Offsets
     39   * check the values are close (=/-500) to the Scan Angle Correct value
     40   * If not then take the average value and use that instead.
     41   * If you change the value make a note on the ticket as it will not match the calibrated value given to us by Leica
     42   * Ask Ops to check the value at the next available opportunity (
    3843 * Uncheck the BIT mode data (we don't need to process this) and run the ALSPP processing
    3944 * Look at the filesizes of the output data.  If the ATN.LAS files are over 400MB in size then Attune will not run. If this is the case re-process with only the part of interest of the line.
    4045   * Part of interest will be the area where all flight lines overlap.
    41473. Ground classification needs to be performed on the files before tie pointing in Attune. But to load the ATN.LAS files into Terrascan we need to first import them into Attune to convert them. To do this we need to start the Attune software
    4248 * We do this so that we only use points on the ground in the tie pointing (since we don't want errors due to perspective or shadowing)
    7581     * Can remove the points from the lower resolution images if it will help. We want more measurements in the higher resolution images than the lower ones if they are unclear to measure in (so don't just measure in them for the sake of it)
    7682   * When happy save the solution - also note down roll, pitch and heading values in case of crashes
    77845. Return to ALS Post Processor
    7885 * Add the Pitch, Roll and Heading values into the boresight calibration dialog.
    8087 * Change output directory
    8188 * Re-run the processing
    82906. Now analyse the results in Terrascan
    8391 * Check profiles etc for misaligning flightlines.
    8795 * To check the Heading accuracy – check the parallel lines for offsets
    8896 * Also possible to check for errors by re-ordering points by elevation
    89987. The boresight parameters can be manually twiddled (rather than using Attune) by reprocessing in ALS, changing the R,P,H values one at time.  Only process parts of the flightlines for speed benefits.