PPT accuracy

[HoustonProud]

Aloha-

I was wondering about a few issues to try and figure out the full functionality of my system. I am working with the PPTx4. First, the standard talk rate between my renderer and vizard is 60 Hz, is there a way to change that? I can find no obvious 'settings' other than threshold and sensitivity. Next, are there specific specs on the error inherent with these motion sensors. I was looking online and in my PPT help and didnt find them off hand. Finally, I need this system for some potentially very fine measurements and may run into issues with these markers. Are there ways to prevent them from moving as much as they tend to for me? More specifically, I am looking to mount a number of these on a torso to get a position of a person walking/running through an obstacle course. The problem is these markers (and the flagpoles(?) on which they are attached to the battery) move around more and dont provide great "rigid" body data. Any and all suggestions you or any other users have would be more than appreciated.

Thanks
email: simpson@bcm.tmc.edu

[mspusch]

A) First, the standard talk rate between my renderer and vizard is 60 Hz, is there a way to change that?

The talk rate is 60Hz, which is the fastest that makes sense, given that the cameras work with 60Hz.

B) I can find no obvious 'settings' other than threshold and sensitivity.

If you click on the calibration button and select options, this gets you into the setup windows. In general, the setup does not need to be changed once the PPT is set up correctly, so this is why the options are kind of hidden.

However, it's all described in the user manual. I'll send you an email with the latest manual to below adress.
You should also consider upgrading to the latest PPT software release, depending on how old your system is. I'll also send you a note about that.
The upgrade is free of charge.

C) Next, are there specific specs on the error inherent with these motion sensors. I was looking online and in my PPT help and didnt find them off hand.

The specs are on the webpage.
http://www.worldviz.com/products/ppt/index.html

D) Finally, I need this system for some potentially very fine measurements and may run into issues with these markers. Are there ways to prevent them from moving as much as they tend to for me? More specifically, I am looking to mount a number of these on a torso to get a position of a person walking/running through an obstacle course. The problem is these markers (and the flagpoles(?) on which they are attached to the battery) move around more and dont provide great "rigid" body data. Any and all suggestions you or any other users have would be more than appreciated.

Depending on your setup, we provide different formfactors for markers, and we also provide you with just the IR LEDs if you want to integrate the LEDs into your own setup.

The PPT is laid out to be a hybrid system, therefore for using an inertial tracker (like Intersense InertiaCube or xSens InertiaCube) for orientation a PPT optical marker for position.