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>

过去数十年来，眼动追踪技术（eye-tracking technology）取得了显著进展，尤其在移动头戴式设备领域。然而，此类眼动仪在静态与动态任务中的精度表现仍存在诸多待解疑问。鉴于此，我们对两款广泛使用的设备——托比Pro眼镜2（Tobii Pro Glasses 2）与托比Pro眼镜3（Tobii Pro Glasses 3）——的性能开展了系统性评估。共有36名参与者参与了三种动态性条件下的任务测试：其一为「下颌托坐姿」试验，仅允许眼部活动；其二为「无下颌托坐姿」试验，头部与眼部均可自由活动；其三为行走试验，参与者沿直线路径行进。在坐姿试验中，参与者需根据语音指示将视线对准墙面的光点；而在行走试验中，参与者需在朝向靶心行进的过程中始终保持视线聚焦于该靶标。眼动仪的精度通过计算机视觉技术识别场景相机图像中的目标物来量化确定。研究结果显示，在行走试验中，托比Pro眼镜3的精度表现优于托比Pro眼镜2。此外，结果表明，对于头戴式眼动仪而言，使用下颌托反而会适得其反：相较于允许头部活动的无下颌托条件，使用下颌托时受试者需要更大的眼偏角才能完成目标注视，进而降低了追踪精度。最后，研究发现，自述工作负荷更高的参与者，其眼动追踪精度也相对更低。本研究结果可为涉及头戴式眼动仪的实验设计提供重要参考价值。