Supplementary data for the paper 'Evaluating the Tobii Pro Glasses 2 and 3 in static and dynamic conditions'

Over the past decades, there have been significant developments in eye-tracking technology, particularly in the domain of mobile, head-mounted devices. Nevertheless, questions remain regarding the accuracy of these eye-trackers during static and dynamic tasks. In light of this, we evaluated the performance of two widely-used devices: Tobii Pro Glasses 2 and Tobii Pro Glasses 3. A total of 36 participants engaged in tasks under three dynamicity conditions. In the “seated with a chinrest” trial, only the eyes could be moved, in the “seated without a chinrest” trial, both the head and the eyes were free to move, and during the walking trial, participants walked along a straight path. During the seated trials, participants’ gaze was directed towards dots on a wall by means of audio instructions, whereas in the walking trial, participants maintained their gaze on a bullseye while walking towards it. Eye-tracker accuracy was determined using computer vision techniques to identify the target within the scene camera image. The findings showed that Tobii 3 outperformed Tobii 2 in terms of accuracy during the walking trials. Moreover, the results suggest that employing a chinrest in the case of head-mounted eye-trackers is counterproductive, as it necessitates larger eye eccentricities for target fixation, thereby compromising accuracy compared to not using a chinrest, which allows for head movement. Lastly, it was found that participants who reported higher workload demonstrated poorer eye-tracking accuracy. The current findings may be useful in the design of experiments that involve head-mounted eye-trackers.<br>

近数十年来，眼动追踪技术取得了长足进步，尤其在移动式头戴式设备领域。尽管如此，此类眼动仪在静态与动态任务中的精度表现仍存在诸多悬而未决的问题。有鉴于此，本研究对两款主流头戴式眼动仪——Tobii Pro Glasses 2与Tobii Pro Glasses 3——的性能展开了评估。总计36名参与者在三种动态性实验条件下完成任务：在「带下颌托坐姿」条件中，参与者仅可转动眼球；在「不带下颌托坐姿」条件中，头部与眼球均可自由活动；在行走任务条件中，参与者需沿直线路径行进。坐姿实验阶段，参与者通过语音指令将视线指向墙面的点状目标；行走实验阶段，则需在朝靶标行进的过程中始终将视线锁定在靶心之上。本研究通过计算机视觉技术识别场景相机画面中的目标，以此计算眼动仪的精度。实验结果显示，在行走任务中，Tobii Pro Glasses 3的精度表现优于Tobii Pro Glasses 2。此外，结果表明，头戴式眼动仪搭配下颌托反而会适得其反：这会要求参与者以更大的眼球偏心角完成目标注视，相较允许头部活动、不使用下颌托的情况，会降低眼动追踪精度。最后，研究发现，自我报告认知负荷更高的参与者，其眼动追踪精度表现也更差。本研究结果可为头戴式眼动仪相关实验的设计提供参考价值。