Hello everyone, does anyone have experience with recording outside while using the Pupil Core set? For example tips on what type of place the calibration is most reliable for the eye tracker?
@user-cd7aec While this probably doesn't answer your questions, here is an interesting article on slippage: https://link.springer.com/article/10.3758/s13428-019-01307-0
@user-973483 @user-bbfd3f @user-cd7aec Interesting article indeed, an attempt to measure eye tracking quality under the influence of slippage. I agree with the authors that “ …. users of mobile head-worn eye trackers perform "(please do not use similar)" tests with their setups to become aware of its characteristics.” In general, there might be a misunderstanding amongst the authors, that is why I would not recommend to perform similar tests.
The methods contain a systematic bias and disfavour Pupil 3D mode heavily. When pupil capture (btw. pupil capture 1.3.13 is quiet old for 2019) detects slippage, it recalculate the position of the sphere of possible pupil centres. This is not a frame by frame calculation and requires several gaze position within the field of fixations. Therefore, during occurring slippage pupil will not provide quality data until it re-established the sphere of possible pupil centres.
The conducted test do not reflection natural visual behaviours in the sense of mimicking realistic slippage and furthermore gazing at a constant central target.
Interestingly Fig 6 should have been repeated for the validation at the end of the recording. Not concurrently but decent work:
@user-bbfd3f avoid direct sunlight or wear a hut. sunlight contains excessive IR light and that can interfere with the eye tracking cameras. cheers
@user-14d189 I'm not a not an expert nor a scientist. I do work with academics that have a lot a experience on subject, including 2 of the writers of the linked article which is how I got introduced to subject of slippage.
@user-973483 I do not think I am an expert either. Slippage is a problem for any head mounted eye-tracker. Just be aware of quality and limitations of the system you want to use. Unfortunately there is not much information out and the only thing about slippage of head mounted eye-trackers is written up in papers. Reviewing my own data helps me a fair bit. The article you linked from Niehorster et al. is indeed a good attempt. It answers an important question. During constant slippage, while fixating on a single target, which is the best eye-tracker to use?
I am just careful to draw any general conclusion from that.