Hu Bo, Knill David C
Center for Visual Science, University of Rochester, Rochester, NY 14627, USA.
J Vis. 2011 Jun 30;11(7):10.1167/11.7.23 23. doi: 10.1167/11.7.23.
Previous work has shown that humans continuously use visual feedback of the hand to control goal-directed movements online. In most studies, visual error signals were predominantly in the image plane and, thus, were available in an observer's retinal image. We investigate how humans use visual feedback about finger depth provided by binocular and monocular depth cues to control pointing movements. When binocularly viewing a scene in which the hand movement was made in free space, subjects were about 60 ms slower in responding to perturbations in depth than in the image plane. When monocularly viewing a scene designed to maximize the available monocular cues to finger depth (motion, changing size, and cast shadows), subjects showed no response to perturbations in depth. Thus, binocular cues from the finger are critical to effective online control of hand movements in depth. An optimal feedback controller that takes into account the low peripheral stereoacuity and inherent ambiguity in cast shadows can explain the difference in response time in the binocular conditions and lack of response in monocular conditions.
先前的研究表明，人类在进行在线目标导向运动时会持续利用手部的视觉反馈。在大多数研究中，视觉误差信号主要存在于图像平面中，因此可在观察者的视网膜图像中获取。我们研究了人类如何利用双眼和单眼深度线索提供的关于手指深度的视觉反馈来控制指向运动。当双眼观察手部在自由空间中运动的场景时，受试者对深度扰动的反应比在图像平面中慢约60毫秒。当单眼观察旨在最大化可用单眼深度线索（运动、大小变化和投射阴影）的场景时，受试者对深度扰动没有反应。因此，来自手指的双眼线索对于有效在线控制手部在深度方向上的运动至关重要。一个考虑到低周边立体视敏度和投射阴影中固有模糊性的最优反馈控制器可以解释双眼条件下反应时间的差异以及单眼条件下无反应的情况。
