Getting fixations via Tobii Pro SDK

[Martin Boschman]

We own a couple of 4C trackers with Pro upgrade licences. Previously we used the EyeX framework to get our fixations. In the Pro SDK however I cannot find a way to filter fixations. Should I use the EyeX framework in combination with the PRO SDK to get the best of both. E.g. I also need to extract pupil data. Therefore I need the Pro SDK. Can you help me out?

Martin

[Grant [Tobii]]

Hi @mcboschman, yes that’s correct that the Tobii Pro SDK does not contain functionality for processing fixations.

However, if you check out the Tobii Core SDK Interaction API available for free @ http://developer.tobii.com/tobii-core-sdk/
Here you can easily get fixation information as shown in the supplied example applications.

The syntax of the new Tobii Core SDK is very similar to the older EyeX SDK, so you shouldn’t have much trouble getting up and running. Please check it out and let us know if you hit any problems.

[Martin Boschman]

OK, I understand. What about the combination of acquiring both fixation data and pupil data? The latter is not supported under the Core SDK. Can I use both the core SDK and the Pro SDK in combination?

[Grant [Tobii]]

Hi @mcboschman, no I am afraid you cannot use both the Core SDK and Pro SDK at the same time unfortunately as they have very different libraries.

However, I will check with Tobii Pro SDK support if they know of any free fixation filter algorithms already developed with that SDK that you could use ,unless you have already asked?

In any event, the methodology we use is open to the public and can read a bit more @ https://www.tobiipro.com/siteassets/tobii-pro/learn-and-support/analyze/how-do-we-classify-eye-movements/tobii-pro-i-vt-fixation-filter.pdf/?v=2012

[Martin Boschman]

Hi Grant,
In the meantime I have tried to read fixation data via Core SDK and the pupil data via Pro SDK within the same application. It provides data that seems to be quite realistic. However, probably I am risking bad performance. Hence, I would be helped with a piece of code that implements a fixation filter.
Martin

[Grant [Tobii]]

Hi @mcboschman, thanks for your patience.. indeed interesting there was no issue in using both SDKs in a single application, though I would certainly be concerned about performance and reliability of timestamp data.

In any event, I managed to find a couple of sources for you in apply fixation filters to raw gaze data which should hopefully be useful. The code used is not necessarily c#, but I think you should be able to translate easily enough.

First link @ https://github.com/davebraze/FDBeye/wiki/Researcher-Contributed-Eye-Tracking-Tools has many different tools across different platforms.

and the Second @ https://es.mathworks.com/matlabcentral/fileexchange/56236-djangraw-gazevistoolbox is not designed for Tobii Trackers but the methodology is compatible.

Please let us know if these are of use to you, and if you manage to create a c# fixation filter kindly share your code for other to use! Thanks.

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