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Tracker Trouble

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Donald Mitchell
Tracker Trouble
on Apr 20, 2012 at 7:02:12 pm

I'm trying to track a circle in a piece of footage that's about 15 pixels in diameter. It's got very good contrast. I set the tracking cross to the centre of the circle and adjust the 2 boxes to just cover the circle. When I track though, the tracker drifts slightly and I have to adjust gaziliions of points.

I find the tracker quite good with finer detail, but how can I get it to follow this circle properly? Is there a plug-in tracker that might do it better? I'd like a tracker that would track the circle shape, and centre the tracking point in the circle.

Any advice much appreciated!


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Benjamin Ausmith
Re: Tracker Trouble
on Apr 20, 2012 at 7:41:08 pm

Your second circle is where After Effects looks for your track, so it doesn't have to scan the entire image every frame. Make your second box bigger, so After Effects has a larger search radius frame-to-frame. That should do it.

Benjamin Ausmith
Post-Production Assistant
Monadnock Media, inc.


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Dave LaRonde
Re: Tracker Trouble
on Apr 20, 2012 at 7:41:22 pm

The outer box needs to be large enough to include the maximum distance the tracking point moves in any given frame. If the footage is all over the place, the box needs to be large. If the camera has a tiny jiggle, the box can be smaller.

But it can't be the same size as the object you're tracking or it will get lost right away, and I imagine that's what you're experiencing.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Donald Mitchell
Re: Tracker Trouble
on Apr 20, 2012 at 8:49:36 pm

ok will try enlarging the second box. But how will the tracker stay in the middle of my white circle? Is that controlled by the inner box?


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Dave LaRonde
Re: Tracker Trouble
on Apr 20, 2012 at 9:00:06 pm

The inner box defines the pattern of pixels that AE looks for in the outer search box.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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