Fig. 1

Study overview. We evaluated if iTracker [11] can provide a cheap, widely deployable method for tracking gaze behaviour using smartphones in ASD patients. a Example of the data collection set-up. We recorded subjects alternating between fixating on the eyes and the mouth of a face printout attached to the screen. Arrows indicate the sequence in which the different facial features were visited. Based on the so obtained videos, we evaluated how well iTracker can distinguish between the two gaze locations. b–e True gaze locations for each of the four tasks in our study. b Task 1: A 4x4 grid of points used for calibration. c Task 2: A face to test how accurately iTracker can separate gaze towards the eyes from gaze focussed on the mouth. d Task 3: Enlarged version of c, to test if separating eyes and mouth improves the ability to distinguish between gaze towards the eyes, and gaze towards the mouth. e Task 4: Subjects trace out a circle. f Outline of the data processing work flow: The obtained videos were split into frames, pre-processed, and gaze predictions obtained with iTracker. Predictions may be refined using a further calibration step