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Motion Tracking a gren laser pointer on slide projection presentation...

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Aza AllenMotion Tracking a gren laser pointer on slide projection presentation...
by on Jun 29, 2011 at 12:20:35 am

Hi all,

I seem to be performing a difficult tracking task, though I thought it would be simple at first...

As stated, I have video of a Powerpoint presentation that I am planning on overlaying a graphic of the presentation on, and the speaker uses a green pointer at various points that I want to track so that I can reinterpret what he is pointing at on the graphic overlay.

I am guessing the problem is that the projection screen is quite bright on the camera, and so is the pointer. I have tried tweaking the options, including tracking the RGB data, saturation, etc., changing the confidence, and what not; and making sure the outside box is big enough to not lose the pointer when it's moved about precariously...

The Motion Tracker won't track AT ALL, doesn't even try to look for it... the box just sits in one spot basically.

Does anyone have a suggestion? Thanks all!

Aza

Make sure to check out our website http://www.makeyourfriendsuncomfortable.com and my personal website http://www.ruesterprod.com


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Steve RobertsRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Jun 29, 2011 at 1:41:36 am

You've altered the footage to enhance the green dot?



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Aza AllenRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Jun 29, 2011 at 2:10:52 am

I just tried that... I exported an uncompressed .avi out of Premiere... I took down all the colors except green, so the green dot shows up nice and bright, and still the tracker won't follow it. Maybe the motion blur is throwing it off... I did change the setting to adapt feature, but still no go...

Make sure to check out our website http://www.makeyourfriendsuncomfortable.com and my personal website http://www.ruesterprod.com


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Walter SoykaRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Jun 29, 2011 at 2:28:34 am

I'd think that this would be an easy track -- can you post a screen shot showing both the footage and your user interface?

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
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Tudor "Ted" JelescuRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Jun 29, 2011 at 7:50:11 am

Would keying the green laser help? I am not quite sure of what you're trying to achieve, but if it's isolating the pointer to be able to comp it on top of the graphics you will comp in, keying may work.
Even if it's a matter of tracking, if you get a good key on the pointer you can then comp white on black using that key and that will give you a clean image to track.

Tudor "Ted" Jelescu
Senior VFX Artist


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David CollinsRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Nov 11, 2012 at 7:56:03 am

A quick and dirty way to track the laser pointer is to place the video segment on top of itself, shifted over 3 frames, and use Subtract blending. This way, only what moves will not be blacked out. Enhance the effect by exaggerating the difference between mid and highlights, and bring down the overall brightness so that the brightest whites are not blown to beyond maximum. Also, use a bloom filter in the layer being subtracted out.


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David CollinsRe: Motion Tracking a gren laser pointer on slide projection presentation...
by on Nov 11, 2012 at 8:06:10 am

A quick and dirty way to track the laser pointer is to place the video segment on top of itself, shifted over 3 frames, and use Subtract blending. This way, only what moves will not be blacked out. Enhance the effect by exaggerating the difference between mid and highlights, and bring down the overall brightness so that the brightest whites are not blown to beyond maximum. Also, use a bloom filter in the layer being subtracted out.

Of course, this really only works best if the video was shot from a stationary camera on a tripod. Which is exactly what I had. My problem is that the pointer is intermittent.


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