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View Full Version : Max system latency for HMD?


vjesse
10-12-2008, 09:38 PM
Hello,

I am trying to determine the maximum system latency for our system that implements Vizard 3.0 software. The following are the specifications:

The HMD is an nVisor SX with dual 1280 horizontal by 1024 vertical pixel resolution panels. The display presents a visual field subtending approximately 50 degrees horizontally by 38 degrees vertically. Stereoscopic images are rendered by a 1900 MHz Pentium computer with an NVIDIA GeForce 6600 graphics card and updated at an average frame rate of 60 Hz.
Head movements are tracked by a three-axis orientation sensing system (Intersense IS250 with an update rate of 150 Hz) and used to continuously update the simulated viewpoint. The position of the participant along the X, Y, and Z planes was tracked via an optical tracking system (WorldViz PPT with an update rate of 60 Hz).

Thanks for any feedback you may have!
Jesse

farshizzo
10-13-2008, 03:00 PM
The latency can vary when using the PPT system. It should be somewhere between 60-80 milliseconds. The latency on the PPT side can vary between 20-30 ms. Assuming you are sending the data using VRPN, this will add another 5 ms. Then on the Vizard side you will have a 32-48 ms latency due to double buffering of the output images.

vjesse
10-13-2008, 03:09 PM
Thank you for the feedback!

j

vjesse
10-13-2008, 05:47 PM
Does the Intersense cube add any additional latency?

farshizzo
10-13-2008, 05:48 PM
The InterSense itself has latency, but it is less than the PPT latency, so it shouldn't add additional latency.