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I just found out about OptiTrack tonight (I own one of the first gen smart navs). I'm going to buy one OptiTrack to start testing and to work with the SDK. I am a developer and have been researching mocap using video based solutions for a while. The main problems with video are motion blur and occlusion, so I'm interested to see if OptiTrack can work for me.
I'm interestedin full-body mocap.

-Mark

Mark:

Cool, glad you checked back on our web site. OptiTrack works at 120FPS so motion blur is not that much of an issue. Full body motion capture is a goal of ours, so we would love to see what you come up with!

I looked over OptiTrackAPI.doc. It wasn't clear to me if it can track more than one dot at a time.

Yes it is possible to track more than one object. The camera frame returned from the interface contains a list of objects that are visible. You can enumerate the objects and pick out the ones you wish to track.

When using Vector, it tracks three objects.

quote:Originally posted by NaturalPoint - Eric Davison:
Yes it is possible to track more than one object. The camera frame returned from the interface contains a list of objects that are visible. You can enumerate the objects and pick out the ones you wish to track.

When using Vector, it tracks three objects.Thanks, I see how to do that now. Another question: will the order of the items always be the same? If not how can I distinguish between mutiple objects?

Hello:

I believe that the order comes in from the current tracked object and then listed on down. This means that you are not going to get the same objects in the same order absolutely every time. The best thing to do is just get all the objects and then write a sorting routine that keeps track of the objects by their location, not their tracking properties from our SDK. I hope this makes sense, as I am not a programer, filling in for EricD!

quote:Originally posted by NaturalPoint - Jim:
Hello:

I believe that the order comes in from the current tracked object and then listed on down. This means that you are not going to get the same objects in the same order absolutely every time. The best thing to do is just get all the objects and then write a sorting routine that keeps track of the objects by their location, not their tracking properties from our SDK. I hope this makes sense, as I am not a programer, filling in for EricD! The problem with that is the location will change since I want to track moving objects. So if I am tracking 14 markers on a person's face, all 14 are going to be in constant motion. If the SDk just returns a list I won't have any way to match up marker 1 with marker 1 to measure how much it has changed. I hope you see what I mean.

Yes, I see exactly what you mean. This is where Eric or Birch can jump in to correct me, but basically, you must create a list of objects and track them from frame to frame via various know methods in the art. We will be working on a face tracking extension to the current OptiTrack device, but don't look for it for a few months or more. Reliable marker identification and tracking is one of the more difficult problems to solve.