Changes between Version 23 and Version 24 of Processing/LidarCalibrationProcedure

Timestamp:

Aug 2, 2012, 10:47:37 AM (12 years ago)

Author:

emca

Comment:

--

Processing/LidarCalibrationProcedure

@@ -88 +88 @@
  * Re-run the processing
 
-6. Now analyse the results in Terrascan
+6. Now analyse the results in LAG or !TerraScan
  * Check profiles etc for misaligning flightlines.
  * To load all flightlines will probably need to use a fence (this is like a region of interest)
@@ -135 +135 @@
  * 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. 
 
-5. Check for offset between bank A and bank B
- * Leica have advised that *some* systems have an offset between bank A and bank B. To check for an offset process a single line using only returns from bank A then using only returns from bank B (ALSPP: Filters > Pre-Proc Filters > Filter Range Bank A/B).
- * Load the results in !TerraScan and check for any elevation difference. 
-    * If there is none then great. 
-    * If a consistent offset is visible then adjust all the values for bank B by this offset. Re-run the line again and check the result.
+
+
 -------
 == Final validation ==
@@ -147 +144 @@
  * To check the Torsion look at cross sections of high altitude cross flight. Flat roads and grassy areas are good. Look for “smiles” in the data. This can be done by looking at the centres of the edges of the overlapping area
  * May also be able to do this by re-ordering points by elevation
-2. Save the final ALS PP options to a .reg file
+
+2. Check for offset between bank A and bank B
+ * Leica have advised that *some* systems have an offset between bank A and bank B. To check for an offset process a single line using only returns from bank A then using only returns from bank B (ALSPP: Filters > Pre-Proc Filters > Filter Range Bank A/B).
+ * Load the results in LAG or !TerraScan and check for any elevation difference. 
+    * If there is none then great. 
+    * If a consistent offset is visible then adjust all the values for bank B by this offset. Re-run the line again and check the result.
+
+3. If full waveform data has been collected then the Trigger Delay values need to be checked 
+ * Use LasHistoViewer to verify that the LAS file is suitable for calibration purposes
+     * check the AGC activity is not jumping around or saturated - value of ~150 
+     * 1 volt is good target for timing offset
+     * Intensity ~ 60-80
+     * waves where there is one discrete return only 
+ * In ALSPP > Ultilies > Load Wave Viewer 
+    * display by time and volts  
+    * the peak of the FW signal and the discrete point should coincide
+    * zoom in and manually calculate the difference in time between the peak of the FW and the first discrete return 
+    * under Options there is a box where the trigger delay can be entered - this can be used to assist in visualising the calibration 
+    * repeat until an accurate result is obtained
+    * check for several waves over varying parts of the flightline and calculate the average value
+    * above and below TPR (transition pulse rate) are independent and calculated separately
+       * below TPR, less than 100,000 Hz 
+       * above TPR, greater than 100,000 Hz  
+ * Make a note in the ticket if either of the trigger delay values have been validated
+
+4. Save the final ALSPP options to a .reg file
+
+
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 == Once finished ==