User Presence and Eye Gaze Data w/o Calibration

[R]

Is it possible to get user presence and eye gaze data without a calibration being performed? I understand this is not the typical use case, but in my application I may have many different users and I just need to determine that a user is present and get a general idea of the location they are looking at.

Thanks

[Grant [Tobii]]

Hi @randr,

It should be easy enough for you to at the minimum detect the ‘presence’ of a user through the ‘are eyes found’ function (documented within the EyeX SDK manual – Example: Engine states)

However, when it comes to tracking the gaze location it is imperative that a proper calibration is performed per user as physiological differences vary a lot between individuals.

[R]

Thanks for the info. I will take a look at your suggestion regarding user presence. Is there any way for me to get any eye tracking data without a calibration? In general, really all I need to know is if the user is looking in one of four areas on the screen.

[Alex [Tobii]]

You can calibrate it for yourself and it will most likely pick up other people as well using your profile. Gaze data might be off by significant distance because of the reasons described in a previous message. So it’s definitely something we DON’T RECOMMEND doing in any commercial/public applications.

[R]

How does the calibration utility in the EyeX engine do this during a calibration where the user is instructed to look at various blue dots in different areas of the screen? Is something like this possible with the Gaze SDK?

[Grant [Tobii]]

Hi @randr, as my colleague stated your only option is to run a calibration per user and risk serious errors in accuracy without recalibrating for new users.

I trust you were at the least able to get the presence functionality up and running?

[R]

Thanks for the info Grant and Alex. I have been looking at possibly invoking the Guest Calibration utility to get an initial calibration that can be used. This works ok but when my application is complete I would prefer to not leave the Guest profile (if my application created it) when the app exits. Is there an easy way to delete this?

[R]

Hello. I have not been able to find the ‘are eyes found’ function. I’m using the C/C++ SDK. If you could point me to a more specific location that would be great. Thanks.

[R]

@grant-rogers @alex8b Any suggestions?

[Grant [Tobii]]

Hi @randr, as I mentioned previously what you are looking for is the User Presence State.

You can either listen to the corresponding event:

using (var eyeXHost = new EyeXHost())
{
eyeXHost.UserPresenceChanged += (s, e) =>
{
bool isValid = e.IsValid; // always invalid at the first callback
UserPresence userPresence = e.Value; // Present | NotPresent | Unknown
Console.WriteLine(“User presence (state-changed event): {0}”, e.ToString);
}
}

Or, ask for the value asynchronously:

using (var eyeXHost = new EyeXHost())
{
Console.WriteLine(“User presence (initial value): {0}”, eyeXHost.UserPresence);
}

Runnable example code is available in the EyeXDotNet samples solution, in Minimal Samples -> MinimalEngineStates -> Program.cs.

[R]

@grant-rogers I am aware of the User Presence State and I have used that, but it does not work if there is no configured calibration. You previously mentioned ‘at the minimum detect the ‘presence’ of a user through the ‘are eyes found’ function (documented within the EyeX SDK manual – Example: Engine states)’ which I thought was something different that I have not been able to find. I thought I may be able to use that without a calibration being done. Maybe I misunderstood what you meant.

[Grant [Tobii]]

Hi @randr,

After checking with some colleagues, you will not be able to detect the presence of users without a calibration profile loaded.

Perhaps you could explain your desire to clear the calibration after each user and we can find a solution.

[Author]

Posts