We present a method to automatically calculate time to fixate (TTF) from the eye-tracker data in subjects with neurological impairment using a driving simulator. TTF presents the time interval for a person to notice the stimulus from its first occurrence. Precisely, we measured the time since the children started to cross the street until the drivers directed their look to the children. From 108 neurological patients recruited for the study, the analysis of TTF was performed in 56 patients to assess fit-, unfit-, and conditionally-fit-to-drive patients. The results showed that the proposed method based on the YOLO (you only look once) object detector is efficient for computing TTFs from the eye-tracker data. We obtained discriminative results for fit-to-drive patients by application of Tukey's honest significant difference post hoc test (p < 0.01), while no difference was observed between conditionally-fit and unfit-to-drive groups (p = 0.542). Moreover, we show that time-to-collision (TTC), initial gaze distance (IGD) from pedestrians, and speed at the hazard onset did not influence the result, while the only significant interaction is among fitness, IGD, and TTC on TTF. Obtained TTFs are also compared with the perception response times (PRT) calculated independently from eye-tracker data and YOLO. Although we reached statistically significant results that speak in favor of possible method application for assessment of fitness to drive, we provide detailed directions for future driving simulation-based evaluation and propose processing workflow to secure reliable TTF calculation and its possible application in for example psychology and neuroscience.

翻译：我们提出一种基于驾驶模拟器，利用眼动追踪数据自动计算神经系统损伤患者注视时间（TTF）的方法。注视时间表征个体从刺激首次出现到感知该刺激的时间间隔。具体而言，我们测量了从行人开始横穿马路至驾驶员视线转向该行人的时间间隔。本研究纳入108例神经系统疾病患者，其中56例完成了TTF分析以评估其驾驶适应性（分为适合驾驶、不适合驾驶及条件性适合驾驶三类）。结果表明，基于YOLO（You Only Look Once，即只看一次）目标检测器的TTF计算方案能高效处理眼动追踪数据。通过Tukey诚实显著性差异事后检验（p < 0.01）发现，适合驾驶组呈现显著判别结果，而条件性适合驾驶组与不适合驾驶组之间无显著差异（p = 0.542）。此外，研究显示碰撞时间（TTC）、行人的初始注视距离（IGD）及危险出现时的车速均不影响TTF结果，但驾驶适应性、IGD与TTC对TTF存在唯一显著交互作用。我们将所得TTF与基于眼动追踪数据及YOLO独立计算的感知反应时间（PRT）进行了对比。尽管统计结果支持该方案在驾驶适应性评估中的潜在应用价值，我们仍为未来基于驾驶模拟器的评估提供了详细指导，并提出可靠计算TTF的标准化处理流程，以拓展其在心理学、神经科学等领域的应用可能。