School of Information Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Department of Mechano-Informatics, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Sci Rep. 2021 Jan 27;11(1):2389. doi: 10.1038/s41598-021-82062-1.
Driver analysis, particularly revealing where drivers gaze, is a key factor in understanding drivers' perception. Several studies have examined drivers' gaze behavior and the two main hypotheses that have been developed are Tangent Point (TP) and Future Path Point (FP). TP is a point on the inner side of the lane, where the driver's gaze direction becomes tangential with the lane edge. FP is an arbitrary single point on the ideal future path for an individual driver on the road. The location of this single point is dependent on the individual driver. While these gaze points have been verified and discussed by various psychological experiments, it is unclear why drivers gaze at these points. Therefore, in this study, we used optical flow theory to understand drivers' gaze strategy. Optical flow theory is a method to quantify the extent to which drivers can perceive the future path of the vehicle. The results of numerical simulations demonstrated that optical flow theory can potentially estimate drivers' gaze behavior. We also conducted an experiment in which the observed driver gaze behavior was compared to calculated gaze strategy based on optical flow theory. The experimental results demonstrate that drivers' gaze can be estimated with an accuracy of 70.8% and 65.1% on circular and straight paths, respectively. Thus, these results suggest that optical flow theory can be a determining factor in drivers' gaze strategy.
驾驶员分析，特别是揭示驾驶员的注视点，是理解驾驶员感知的关键因素。已有多项研究对驾驶员的注视行为进行了研究，提出了两个主要假说：切线点（Tangent Point，TP）和未来路径点（Future Path Point，FP）。TP 是车道内的一个点，驾驶员的注视方向与车道边缘相切。FP 是道路上单个驾驶员理想未来路径上的任意单点。该单点的位置取决于驾驶员个体。虽然这些注视点已经通过各种心理实验得到了验证和讨论，但不清楚为什么驾驶员会注视这些点。因此，在这项研究中，我们使用光流理论来理解驾驶员的注视策略。光流理论是一种量化驾驶员感知车辆未来路径程度的方法。数值模拟的结果表明，光流理论可以潜在地估计驾驶员的注视行为。我们还进行了一项实验，将观察到的驾驶员注视行为与基于光流理论的计算注视策略进行了比较。实验结果表明，在圆形和直线路径上，驾驶员的注视可以分别以 70.8%和 65.1%的准确度进行估计。因此，这些结果表明，光流理论可以成为驾驶员注视策略的决定因素。
