De-Fishing and Stabilizing PV Video

[ToddSmi]

If you decrease your fov, vibration will be more noticable. And I like a wide fov.

I don't complain about the distortion, I complain about the wobble / banana effects after stabilizing distorted footage.

When you say wobble, are you talking about the jello effect or something else? Good stabilization software can get rid of both jello effect (also known as rolling shutter), and wobble as well. But I think your choice of P1 with gimble is a good one if you want to reduce editing time. I have the vision because I like the long flight time, but I may upgrade to the Phantom Pro or whatever they are calling it when it is soon released - some are saying January time frame. You may want to hold out for this one as well.

 

[Ton4]

No, I am not talking about jello.

The thing is that the lens distortion (after stabilization) causes this wobble, that I am talking about:

At the top of the image (and left, right and bottom for that matter) there is more distortion as there is closer to the center of the image.

If you stabilize the footage, the footage is actually displaced (and zoomed) in by the software a bit in order to remove the "shake".

However, a change of direction of the lens, changes the amount of distortion. If the horizon is perfectly in the middle, it is horizontal, if you tilt down or up, the horizon becomes more "round", increasing distortion with increased tilt angle.

Now, if you stabilize your tilt (compensation for vertical displacement), you will see the horizon "wobbling", because at different positions in the original frame, it has a different "shape", roundness, distortion.

So, no matter how good your stabilization software is, it needs to be aware of the typical distortion of the lens used, or else there will be "wobble".

In other words, if your perfectly horizontal level lens keeps the horizon perfectly horizontal without distortion at all tilt levels, no wobble. (and the same for vertical of course). So, any lens with barrel or pincushion distortion will cause wobble. However, with extreme distortion as the PV lens it is really attraction attention. With some other lenses, or different POV of the PV lens it is not really annoying.

In my attempt, in my previous post, i first tried to remove the distortion, so the stabilized version would not have wobble. I succeed only partly, probably because I could not determine the correct lens distortion parameters. (I don't actually have the camera to try to get the correct parameters)

Now, if the Adobe lens thingy is 100% correct in adjusting for distortion, this would give (in theory) a wobble free stabilized footage. But I did not try this myself, because in my setup (old photoshop) it would take days to render a movie with decent quality with the Adobe lens correction applied.

I hope someone else tries and will show the results.

 

[Ton4]

Anyways, I decided to not buy the Vision, but buy a classic phantom with gimbal. Stable footage with the fish eye distortion is acceptable in my eyes,

So many folks complain about fisheye when using GoPros because they don't understand the camera.

Don't like fisheye?

Change the capture settings.

It's so simple yet so many people struggle with understanding their equipment.

Maybe people want the same wide angle but with less distortion. Its a matter of lens construction. It is possible to achieve less distortion with the same FOV. But it probably would make the lens more expensive and heavier.

 

[Ton4]

Ah, Dave V has posted a Photoshop corrected video in another post:

http://www.youtube.com/watch?v=iyMZrvusfFQ

While stabilization looks pretty good, it has the "wobble", especially at about 17 seconds, when he pulls up, there is a big wobble.

When he pans horizontally the wobble is barely noticeable, but still present.

 

[gpauk]

Yes - he's illustrated perfectly what you were describing!

 

[Ton4]

I suddenly realized what the wobble actually is.

Even if your lens is perfectly linear (or if your distorted lens is perfectly corrected), it will appear, if there is tilting.

Stabilizing software compensates, seemingly, only for pure up and down motion, while it actually should also compensate perspective changes based on motion.

The wobble is a shift in plane/perspective.

It could be compensated by software.

Somebody should file a patent for this

Anyways, the gimbal is on its way. No wobble for me. :mrgreen:

 

[ToddSmi]

Ah, Dave V has posted a Photoshop corrected video in another post:

http://www.youtube.com/watch?v=iyMZrvusfFQ

While stabilization looks pretty good, it has the "wobble", especially at about 17 seconds, when he pulls up, there is a big wobble.

When he pans horizontally the wobble is barely noticeable, but still present.

Okay, now I follow what you were saying. But I do have to say that I've gotten much better results than this from software stabilization. Not all software is created equal and you sometimes cannot just use the default After Effects settings. Sometimes have to change the parameters around a bit depending on the type of footage you shot. Also, it helps to adjust your shooting style (i.e., in this case flying style) to take into account the deficiencies in the lens and gimbal setup that comes with the P2V. And flying in ATTI mode is much better for smooth video than GPS mode. Bottom line...even the P2V setup can do much better than what this video shows after thoughtful shooting and good stabilization software. Oh, and one other thing...the wobble that you referenced at about 17 seconds occurred because he manually tilted up the camera while he was flying. That will always look bad no matter how its stabilized, because the camera tilt speed is very fast on the P2V (unless you change the manual gain setting in the DJI software). But I think you will be happier with the P1 and brushless gimbal!