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Here is a video of a GoPro falling from a plane: http://www.youtube.com/watch?v=QrxPuk0JefA

Any idea what is happening when the image "stabilizes" around 0:35? I think it is because the camera's tangential velocity approaches the speed of the GoPro's rolling shutter.

Follow-up question:

  • Why is the image skewed with the left side skewed "up" and the right side skewed "down?"

A challenge:

  • Find the axis of rotation (with supporting diagram and explanation of how it was computed).
Arthur L
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    Also, I'm inclined to agree that the stabilizing might be due to aliasing due to the rotation of the camera, but I'll await the judgement of people who look further in depth. – DumpsterDoofus Feb 25 '14 at 01:11
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    Related: http://physics.stackexchange.com/q/75709/2451 – Qmechanic Feb 25 '14 at 01:19
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    @DumpsterDoofus: No way, that was awesome. I suppose the camera was dropped accidentally... – Kyle Kanos Feb 25 '14 at 02:01
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    But the pig... It was eating the camera. They're not supposed to eat cameras. – DumpsterDoofus Feb 25 '14 at 02:02
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    I'm almost certain the "stability" was simply a matter of the framerate. As you listen to the video you can hear it spinning even when it appears not to be. Extract out the audio, do a spectral analysis and you'll find that the frequency of the audio is some integer multiple of the framerate. – Brandon Enright Feb 25 '14 at 02:20

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It looks like something that the older analog TVs had called a vertical hold.

My answer is that the frames per minute taken by the camera is equalizing the rotation/spinning of the camera. It was chance that they got the ground in the frame. You can kind of get the same effect when filming a helicopter's rotor and it looks stationary. https://www.youtube.com/watch?v=cxddi8m_mzk

Muze
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