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Get position data of area with highest value each frame of a sequence

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Simon Ender
Get position data of area with highest value each frame of a sequence
on Jul 23, 2010 at 8:43:56 am

Hi,

I'm trying to find a way that after effects gives me position data of the brightest spot each in frame of a sequence. I have to add lightning to a very long sequence and I want the lightning start to position itself automatically at the brightest spot of each frame in my sequence. Like tracking, but not tracking motion, but the highest value in a sequence over time. Does anyone know how I could achieve that? With a plugin or script or on board tools?

Thanks,
Simon


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Michael Szalapski
Re: Get position data of area with highest value each frame of a sequence
on Jul 23, 2010 at 2:52:01 pm

You could crush the levels and use motion tracking, but it's probably something that should be done by hand.

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Simon Ender
Re: Get position data of area with highest value each frame of a sequence
on Jul 23, 2010 at 6:13:00 pm

Thanks for your reply. I tried something like that, the problem is, the footage has 25 Megapixel resolution and the tracker freaks out, when I crank up the search area that big.
Finding the brightest spot(s) in an image is such a simple thing, I think there must be a way to get the position of those areas. Image Lounge's "Highlight Selection" plugin finds all that spots an makes twinkles where they are, but I can't figure out how to get/reveal the data it uses.

Simon


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Dave LaRonde
Re: Get position data of area with highest value each frame of a sequence
on Jul 23, 2010 at 7:11:01 pm

[Simon Ender] "..the footage has 25 Megapixel resolution and the tracker freaks out, when I crank up the search area that big..."

Well, then don't make the search area so big. It only needs to be as big as the point to be tracked can move in one frame... plus a little extra for safety's sake.

Just so we understand what's going on, what the H & V dimensions of this thing?

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


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Simon Ender
Re: Get position data of area with highest value each frame of a sequence
on Jul 23, 2010 at 11:07:01 pm

The thing is, that I don't have to track a point that moves within a certain area. What I did is the following: I created the illumination the lightning causes on the cloud footage (approx. 10000*2500px) by the means of an animated turbulence. Now I have clouds that are randomly illuminated over time (1-2 frames each time). The only thing that is missing is the lightning strike. And since the sequence is more than 1500 frames in duration I want the start point of the 'advanced lightning' filter of AE to automatically place itself in the/an illuminaed area/s which are the areas with the highest value. The end point would than have to be offset accordingly via a simple expression.

I'd appreciate any hint on that. But maybe I have to do it manually. It's just that one would think that it is kind of an easy thing for some plugin or filter to find the brightest spot/s and output the position.

Thank you,
Simon


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Chris Mcfall
Re: Get position data of area with highest value each frame of a sequence
on May 3, 2011 at 11:09:14 am

Hii Guys Did anyone ever find an answer to this? I'm in exactly the same boat, trying to set a null to track the brightest point...


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