Pupil Labs Neon eye data output - logged_time vs time?

Coding
1

Hi all -

Context: I am using the Pupil Labs Neon and the associated plugin for psychopy. I’m using the eye data (specifically the BinocularEyeSampleEvent data) from the hdf5 file output.

Issue: I’m having some confusion on what is the difference between “logged_time” and “time” variables within this data. Neither starts at time 0, and “logged_time” seems to be less consistent in frequency, while “time” has a consistent frequency. However, I’ve had instances where “time” will completely drop (here, the time is written -4.6772e+04) for up to 0.5 seconds, while “logged_time” will continue. This is largely a problem because I need at least 10 ms resolution.

Question: What is “logged_time” vs “time”? Has anyone experienced the “time” drop?

Thanks!

- Dav

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Dear Dav,

I would suggest you look at the Pupil Labs documentation. They explain the data output (both with psychopy and without) there: Neon - PsychoPy - Pupil Labs Docs

However, it looks to me like you haven’t setup the data output or recording correctly, specifically in the neon app. To me it looks like it’s a 200hz camera (so you’d get a timestamp every 5ms), but there’s sample drops occurring, and double sampling (some timestamps are the same).

Overall, I assume logged_time is neon’s internal timer, and time is psychopy’s. Not sure what happened with those null values.

Issac