Low Altitude Aerial Photography

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  • #683

    Jon Caris
    Moderator

    With field season soon upon us, I’m ramping up our efforts to capture low altitude aerial photography via kite, balloon, and quadcopter or uav (please don’t say drone).  Curious if there are others who would like to discuss plans and ideas for these exciting new and engaging tools.   The publiclaboratory is a great resource and should be given credit for revitalizing these techniques and demonstrating the value of citizen science.

    Smith College has flown 2 kite missions (Maine and Belize) and we’ll certainly be doing more this spring and summer.  Of course, I’m interested in the flying (who isn’t?), but also the methods and techniques for processing the imagery, developing exercises/ workshops for students and faculty, and tool building (modifying flight and image capture equipment for better performance).

    Thoughts?

    #709

    Anonymous

    I was  previously  involved with RMIT University’s remote-controlled blimp, and I’ve been to demonstrations of small UAVs, but I thought the entry cost was prohibitive. The Belgian Gatewing UAV, for example, has a $100K price tag, which includes the flight control and imagery stitching software. It uses an off-the-shelf consumer digital still camera.

    Arko Lucieer at the University of Tasmania has been doing very exciting hyperspectral work with an octocopter mapping vegetation on Macquarie Island [the TerraLuma project, http://www.terraluma.net/ ]. Macquarie has a very unforgiving climate, very windy and wet, but he has been mapping over a large area to about 20cm precision.

    I’ve been experimenting recently with a remote control quadcopter, the DJI Phantom, which is an off-the-shelf product. There is a remarkable amount of information about build-your-own quadcopters, of which I was previously completely unaware, so this was my first toe-dip, and one in which the learning curve has been steeper than I expected.

    The DJI Phantom is less than $700, and is GPS-equipped, so it can hold position and also [fortunately for me] has a return-to-home function if it loses contact with the controller. It is a consumer product, but a very sophisticated one, unlike the AR Parrot. It is very easy to control, remotely-piloted, but not programmable [i.e. it is *not* a UAV]. To use it for gathering imagery, you have to pilot it yourself. Very soon you start adding things to the outside of the airframe; a camera, a video downlink transmitter and receiver so you can see what it is seeing, an on-screen-display module for telemetry, etc., etc. The payload limit is around 900 grams, but you quickly end up with a forest of wires, video and power, and instruments, as you gradually add pieces. I think it would be a great teaching tool, in the sense that you have to understand how the various pieces work together, rather than being a fully integrated product.

    If you have a consumer-level camera with GPS tagging, it is easy to acquire imagery, and then use open-source or commercial stitching programs to create a mosaic. You have to quickly understand things like FOV, image intervals, flying height, but the positional stability of the quadcopter under GPS control is pretty good. If you wanted to, you could take a snap, move along, take another, etc. Getting a usable mosaic is non-trivial, because you can’t pre-program the flight path, but you do learn how to do point-to-point flying, and you also make sure to take a lot more images than you think you’ll need, because you *will* need them.

    Michael McBain

    Melbourne, Australia

     

    #710

    Anonymous

    The journal <i>Remote Sensing</i> has a special issue devoted to aerial imagery acquisition from UAVs. See:

     

    http://www.mdpi.com/journal/remotesensing/special_issues/uav

     

    Michael McBain

    Melbourne, Australia

    #723

    glennon
    Participant

    For kite equipment, I have been happy with brooxes.com gear. At spatial@ucsb, Kitty Currier and I have endeavored to create inexpensive aerial platforms. One of my favorites is the Discavet– a self-leveling rig made from a compact disc, plastic bottle, twine, cable ties, tape, notebook clips, and a toy screw. It uses a Picavet suspension. See: http://www.flickr.com/photos/jaglennon/4590225417/in/photostream/

    Gyro servos are now fairly easy to acquire (though about $65-$70/each), and could make for some fun hacking.

    Concerning software tools for basic georeferencing and partial orthorectification (to reconcile sensor alignment of aerial images), here are a few I use:

    mapknitter (open source)  link
    mapwarper (open source) link
    ArcGIS via the Georeferencing toolbar (proprietary) link

     

    Alan

    #727

    Diana Sinton
    Keymaster

    Nice collection of resources developing here!   Jon – yes, that Public Laboratory site (PLOTS) has info on guiding beginners on these balloon and kite mapping projects.

    Jeremy Crampton at the University of Kentucky is also using these systems with his undergrad students; here’s a story about his work.

    Diana

    #913

    Anonymous

    Thanks to new technology such as “drone” that is effective for any kinds of video and filming. We have been doing great in all our video coverage since this technology started. Also, we have been been in contract for the service of http://www.debbieirwin.com/ that makes the video film narrations and voice overs for our commercial videos. The aerial photography even more useful, effective and very compact and easy to use just by using remote access from the ground for the drone to work.

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