phantom markers

yoann.dess
Posts: 6
Joined: Thu May 27, 2010 1:13 pm

phantom markers

Post by yoann.dess » Thu May 27, 2010 1:49 pm

Hello,

I am a new user of tracking tools software. I work about walk analysis and I have some problem with phantom markers that display. Doest it exist a part for post-treatment and remove these phantom markers ? If no, is it planned to develop this in the next update ?

Thanks

Yoann

VincentG
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Joined: Mon Jul 17, 2006 5:00 am
Location: Corvallis, Oregon

Re: phantom markers

Post by VincentG » Fri May 28, 2010 3:17 pm

What type of phantom markers are you getting?

Have you tried recalibrating the software?

Can you determine where the extra markers are coming from?

Jim
NaturalPoint Employee
NaturalPoint Employee
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Location: Corvallis, Oregon
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Re: phantom markers

Post by Jim » Mon May 31, 2010 3:31 pm

Phantom markers can be caused by several things, reflections in the room, software settings, or calibration.

Are the markers appearing next to real markers, like they are splitting, or are they just random in a scene?

I would first check your calibration, look at the residual value, make sure it is less than 1mm or so.

Also try turning on display of "rays" and "untracked rays", it can help determine if there are particular cameras which might be poorly calibrated.

You can strip these out when you export the data, if you are not exporting all unlabeled markers.

yoann.dess
Posts: 6
Joined: Thu May 27, 2010 1:13 pm

Re: phantom markers

Post by yoann.dess » Tue Jun 01, 2010 7:05 am

The phantom markers are appearing next to real markers, like they are splitting. I watch the rays and it's often the 2 further cameras that don't find the same markers coordinate that the others cameras.
I calibrated several times and I have always the same problems in spite of low values of std errors 2D and mean errors 2D.

Yoann

VincentG
Posts: 7728
Joined: Mon Jul 17, 2006 5:00 am
Location: Corvallis, Oregon

Re: phantom markers

Post by VincentG » Tue Jun 01, 2010 1:22 pm

What version of the Tracking Tools software are you using?

How do you have the cameras arranged, for the setup area?

yoann.dess
Posts: 6
Joined: Thu May 27, 2010 1:13 pm

Re: phantom markers

Post by yoann.dess » Fri Jun 04, 2010 11:50 am

I have the version 2.2 beta 1.

The camera were placed on a square of 20 feet around the walkway, almost like showed on the optitrack site : http://www.naturalpoint.com/optitrack/i ... 2truss.jpg.
Two cameras are in each corner and the last four cameras are on the sides of the walkway. Every cameras see the center of walkway the force plates are placed.

VincentG
Posts: 7728
Joined: Mon Jul 17, 2006 5:00 am
Location: Corvallis, Oregon

Re: phantom markers

Post by VincentG » Fri Jun 04, 2010 1:47 pm

Can you send in copies, of your calibration, capture, rigid bodies, etc. to support.

The_Nomad
Posts: 57
Joined: Tue Mar 04, 2008 9:55 am

Re: phantom markers

Post by The_Nomad » Thu Jun 10, 2010 8:42 am

Interesting. We've had lots of problems with phantom markers too, usually a third phantom appearing between the two foot markers. We'll see if the new wand sorts that problem out.

yoann.dess
Posts: 6
Joined: Thu May 27, 2010 1:13 pm

Re: phantom markers

Post by yoann.dess » Sun Jun 13, 2010 12:51 pm

I haven't the new wand so could you say me if the problem disappear with him ?

kahl_hellmer
Posts: 10
Joined: Fri Sep 14, 2007 7:33 am
Location: Uppsala, Sweden

Re: phantom markers

Post by kahl_hellmer » Tue Jun 22, 2010 1:05 pm

Try using a carpet if you're on a hardwood or plastic floor. Reflections from other cameras' lights can be reflected by the floor and cause strange reflections by the feet.

Kahl

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