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Pix4D Model Power Lines

Discussion in 'Photos and Video' started by NorthernObserver, Jul 6, 2015.

  1. NorthernObserver

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    Ph2 GoPro 3 Black
     
  2. G_Thomas

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    Hello Northern Observer,
    Nice job. I have a project doing something similar with our Phantom 3; from the video it looks like you flew this taking nadir photos, is this correct? also, were there particular processing settings in Pix4d at the point densification stage in order for it to get the wires?
    Cheers,
     
    Northern Observer likes this.
  3. Northern Observer

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    Nice to see other people looking at multi-ray photogrammetry for line route and transmission line analysis. First of all this line model in the video was flown with a Phantom 2 carrying a GoPro 3+Black camera. The GoPro 3+Black camera is of course a fish eye lens whereby the camera on the Phantom 3 camera is not.

    What I found: Two or three NADIR image flight lines with say 90% overlap longitudinally and 60% overlap transverse along a line route will capture near Lidar quality point clouds on the right of way objects, visible terrain, and vegetation. With good tie points, you can't tell the difference Lidar vs. Pix4D. To capture conductors will require 3 or more parallel flight lines with a wide angle lens to increase the overlap. Success in Pix4D is all about overlap. Conductors are difficult to acquire, but not impossible. Massive overlap is needed.

    The obvious connection to you if you are working in the transmission line field: If you have transmission lines previously flown by Lidar and there are no changes to the sag and tension apart from predictable creep, then you don't require new points in the line model. Its difficult to tell non-engineers that, who have no idea how a large power cable sags.

    Major Point: Change detection surveys can use multi-ray photogrammetry via drones or small aircraft and save a lot of money on line refresh surveys.

    I hope this helps, If you would like to discuss further, please send me a PM.


    Side note:
    I had more flights and study with my P3 planned, but I lost the entire flight season in 2016 because the compass on my P3 failed several times with DJI unable (or unwilling), (or too stupid), to repair it (they tried 3 times) That all said, I hope to have my new replacement P3 this week. The company I purchased the P3 from is giving me a new one. DJI = MAJOR FAIL.
     
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