GP3 Eye Tracker Data "Events" - Reading HDF5 Files

Coding
1

Hello,

Based on what we have seen so far, it appears the data from the GP3 events, when run through PsychoPy are stored as HDF5 files. What is the best way to access these files? And is there anywhere else that the events data goes/ can alternatively be accessed?

Thank you in advance,
Courtney

2

There is a free application called HDFView that allows you to graphically browse an HDF file. HDF is a long-standing format for efficiently storing large datasets in a relational style rather than in a single flat file.

As such, there are many APIs for accessing data from them programmatically, including from Python.

1 Like
3

Hi

I had a lot of issues with this aswell.
to get it working I used example experiment GC_cursor
Located in “psychopy\Lib\site-packages\psychopy\demos\coder\iohub\eyetracking\gcCursor”
It generated a hdf5 file, which I viewed using [hdfview] (remember to choose the version corresponding to your operating system, and yeah you do need an account in the HDFgroup)(https://www.hdfgroup.org/downloads/hdfview/):

When viewing the output hdf5 file, I saw that the GazepointSampleEvent

Screenshot_7
Screenshot_71991Ă—1360 160 KB

had 1301 rows, whereas the BinocularEyeSample event had 0 rows
Screenshot_8
Screenshot_82068Ă—1361 170 KB

Then i looked into analysis solutions, here there is a github with a tobii solution using R
to reading the hdf5 files. However in this code it looks for the BinocularEyeSample
So in my script, attached (very hacky), i ask for the GazepointSampleEvent rather than the
BinocularEyeSample.

When running the analysis code (attached), the object “tobiiData” contained the following:

Screenshot_9
Screenshot_92348Ă—1348 159 KB

Which is all the data, every 2 ms.
Similarly the eventsData contained the messages. i.e. TRIAL_END and TRIAL_START.

the gaze_analysis.R requires you to run: install.packages(“hdf5r”)
first. Keep in mind its just a quick hacky example to get the data.
gaze_analysis.zip (1.3 KB)