sampling frequency and reliability

[bc]

Hi! I'm looking to use your plug in to record hand positions for patients in a clinic, while they perform reaching exercises. What are some stats on the performance of your recording? Does it affect frame rate? What is the sampling frequency for the postures of the controllers and HMD? How do you save the data, and do you save it to disk? What is the best way for me to export the data to JSON/csv/any file on disk? Do you get the acceleration data from the controllers, or just the pos + rot? Thanks so much, and thanks for contributing your code!

Brian

[andrewjc]

Hi Brian!

Thanks for checking out the code. It's been awhile since I stopped working on it but here goes:

• all recorded data frames are stored in ram in a linkedlist and written out to disk when you stop recording.
• frame rate during recording is not affected.
• sample rate is configurable both during recording and playback as separate variables. Look into VrPlaybackDevice and VrRecorder I think are the classes.
• I don't believe accelerometer data is captured, only matrix transform data.
• You could calculate fake acceleration data across data frames samples at a constant rate. Second derivative of position should give you what you need.

Cheers, Andrew

On Thu, 9 Aug. 2018, 9:35 am Brian Cohn, [email protected] wrote:

Hi! I'm looking to use your plug in to record hand positions for patients in a clinic, while they perform reaching exercises. What are some stats on the performance of your recording? Does it affect frame rate? What is the sampling frequency for the postures of the controllers and HMD? How do you save the data, and do you save it to disk? What is the best way for me to export the data to JSON/csv/any file on disk? Do you get the acceleration data from the controllers, or just the pos + rot? Thanks so much, and thanks for contributing your code!

Brian

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[bc]

Thank you so much for your support on this!

• all recorded data frames are stored in ram in a linkedlist and written out to disk when you stop recording. Does the data have a timestamp associated with it? And what happens if I run a session for a long time, with every frame recorded? Is there a way to know when it would overflow?

• frame rate during recording is not affected. AWESOME
• sample rate is configurable both during recording and playback as separate variables. Look into VrPlaybackDevice and VrRecorder I think are the classes.

It gets the controllers and the headset. How would I include an additional Vive Tracker?

• I don't believe accelerometer data is captured, only matrix transform data.
• You could calculate fake acceleration data across data frames samples at a constant rate. Second derivative of position should give you what you need. Definitely.