Hi! I’m having an issue with Pupil Invisible. It worked normally before, but now: Recording starts and the timer runs, A file is saved, but it’s empty (no world-camera video, no fixations/blinks), The first-person camera view no longer appears during recording. Nothing in the settings was changed. Any idea what could cause this or how to fix it? Thanks!

yes, the world camera is securely fixed

Hi @user-f43a29 , could you guide on where to find pupil diameter in the timeseries data?

Hi @user-25e964 , do I understand correctly that the phone will be used as a kind of viewport into the AR scene? Do you want to know where they look on the surface of the phone or do you want to additionally project gaze into the AR coordinate system?

Ok, there are two methods that come immediately to mind:

• You can use AprilTags to detect when the phone screen is in view of Pupil Invisible's camera and then project gaze onto that detected surface. You could present them as images or print them out on paper, similar to the method demonstrated in this Blog post.
• You can use a DNN like Yolo to detect the screen without markers and similarly project gaze onto the screen.

Then, you check for the following correspondence of events:

• Gaze is on screen
• The rendered landmark is visible
• And, The currently "gazed pixel" corresponds to the image of the rendered landmark.

Depending on the power of the computation device that will receive the Pupil Invisible data, either of these methods could potentially be used in real-time.