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DroneMapper Aerial Imagery and UAV Mapping 'Best Practice' Guidelines

Posted by JP on April 25, 2012 at 3:00pm
medium_route1map.pngHow to get good results on your mapping mission with any backend processing service!
  • Imagery should have at least 60% overlap and should have at least 20% orthogonal overlap.
  • Imagery must be shot in sequence. See examples below.
  • Images must contain required EXIF information. [more]
  • Images are shot with one camera and focal length.
  • Images should not be pre-processed. (i.e. Lightroom, Picassa, etc)
  • Images are NADIR or near vertical.
  • Flight Path should be Parallel Line (aka Lawn Mower) or other large overlapping style.
  • Flight Path should provide sufficient coverage of survey area. Meaning a large amount of overlapping images for target area.
  • Flight should be from sufficient elevation. (i.e. >80 meters)
  • Try a small subset of your imagery as a test. We process 15 images or less for free!


Flight Mode / Geolocation Guidelines:

  • Use a supported Flight Controller with supported export format. [more]
  • Sync your camera internal time with your flight controller GPS time. [more]
  • Imagery EXIF timestamps must match flight controller log timestamps to obtain rough georeference.
  • Flight Controller log exports should be in WGS84 for Latitude and Longitude. Elevation in (m) above the earths surface or actual elevation of image. Camera direction in (d).
  • Each image must have a matching GPS/IMU log entry.
Imagery Sequences with Problems:


possibleerror1.PNG?width=750
The imagery sequence above may experience problems processing due to image P1020271.JPG. This image does not have connecting
control points between P1020270.JPG and P1020272.JPG. Note: This is a small subset of over 100 images.

medium_route1map.pngFlight Path




badsequence.PNG?width=750
This sequence attempts to show aerial images with a small amount of overlap shot out of sequence. You can see the flight path does not

include a large amount of imagery overlap.

medium_route2map.pngFlight Path



 


Imagery Sequences with Good Results:


goodoverlap3.PNG?width=750
This sequence shows a good amount of overlap between images. A large amount of control points are detected in order to scale, rotate and mosaic. This is a small subset of over 241 images.

medium_route3map.pngFlight Path




goodoverlap2.PNG?width=750
An example of a flight from Pteryx UAV with a large amount of overlap. This is the idea situation.

medium_route5map_0.pngFlight Path




goodoverlap4.png?width=750
Another example of an imagery sequence with a large amount of overlap.

medium_route4map.pngFlight Path



Hope this information helps all you UAV mappers out there. Cheers,
JP Stoermer
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Comments

  • JP April 27, 2012 at 6:24pm

    @Jasja sometimes EXIF tags are stripped out with this type of software. thx

  • Developer
    Michael Oborne April 27, 2012 at 5:53pm

    @Joseph, yes, they do disapear as they dont store coords.

  • UAS_Pilot April 26, 2012 at 9:03pm
    Michael, I tried that before but when I do that the waypoint disappears fron the flight planner. Is that normal?
    Thanks
  • Jasja Dekker April 26, 2012 at 7:08am

    What is wrong with preprocessing, in your opinion? I've had no problems getting good quality maps from processed images!

  • JP April 26, 2012 at 5:47am

    @Gareth we use a bunch of different method and techniques. Take a look at gdaldem, gdal utilities and also RunSFM, I have had good luck with these. :) 

  • Gareth Rens April 25, 2012 at 11:27pm

    What software do you use to generate the DEM ?

  • Developer
    Michael Oborne April 25, 2012 at 9:23pm

    either use relay repeat, or servo repeat.

    or use a camera that had a repeat function, such as canon powershot cameras with chdk

  • UAS_Pilot April 25, 2012 at 8:50pm
    How do you program the mission planner to take a shot every so many feet?
This reply was deleted.