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Tilted and curved horizon

Discussion in 'Pro/Adv Discussion' started by FredzMaxxUAV, Dec 25, 2015.

  1. FredzMaxxUAV

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    What do you guys think of this? P3P v 1.4. What can I do to fix it, both the tilt and the curve?
    [​IMG]
     
  2. Dirby

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    try a cold imu calabration.
     
  3. Dirby

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    also a gimbal calabration
     
  4. FredzMaxxUAV

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    Is it normal the horizon is curved when you move the gimbal down (so there's less sky)?
     
  5. Meta4

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    No ... it's hard to see if your horizon is really curved or if it's just the shape of the land.
    Find a good horizon over water or flat land and you can experiment with camera angles to see.

    For the camera tilt, try a gimbal calibration and adjust the gimbal roll if needed.
     
  6. FredzMaxxUAV

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    Thanks Meta4. Adjusting gimbal roll helps, but sometimes I need to change the roll manually, which is odd. Maybe there was also too much wind.

    For the curve, see below. No curve when gimbal is in normal position, but a curve appears when the gimbal is down. What do you think?

    [​IMG]
    [​IMG]
     
  7. 2nd2non

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    The curve (distortion) with gimbal tilt is normal and a feature of the P3 camera
    It's just one of those trade offs given the lens properties and FOV. Nothing you can do unless correct it in post
     
  8. skyeboysteve

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    The curve is from lens distortion. If you use photoshop you can remove that distortion under the filter menu. Just select DJI, 300x. Fortunately photoshop has a lens profile for DJI lenses.

    As for horizon tilt, it's just something you have to live with (and adjust in your favorite editor). Normally mine keeps level pretty well in certain directions then while in a rapid yaw will tilt a couple degrees. After stopping yaw movement for a few seconds the tilt levels up again though sometimes not perfectly (but usually within a degree) unless facing north or south in un accelerated flight then it's level.
     
    ianwood likes this.
  9. FredzMaxxUAV

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    Right... Correcting on photos is easy. But on 4K movies?
     
  10. skyeboysteve

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    4K does takes time. Just don't forget to convert your video clip to "smart filter" before applying lens correction otherwise it will only effect the frame your previewing. On my rig it can take about 7 hours to process 10 minutes--that's with 64gb of ram, I7 3930K over-clocked to 4.5ghz.
     
  11. jimerb

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    You can fix the barrel distortion (curve) with Lightroom too. You can fix video this way in premiere pro but at a heavy cost in processing (every frame needs to be corrected.)
     
  12. mirrorimage

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    What's a cold IMU calibration? How is this different from regular IMU calibration. My new P3P (2nd one) gimbal always has a tilted horizon. Once the bird is up in the error I calibrate the gimbal, and it snaps to a better position, but is still slightly off. It's very frustrating. It's like it's not remembering it. I never had any of the tilted horizon problems on my first p3p.
     
  13. FredzMaxxUAV

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    Same here. Oldest P3P is always fine, newest one (new motors and shell) always has this problem. Disappointing...
     
  14. rene van der meer

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    Also the wind can influence tilt. Try rotating the AC if the tilt changes, the wind causes it.