What visual information is used for stereoscopic depth displacement discrimination?
What visual information is used for stereoscopic depth displacement discrimination?
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DOI：
10.1068/p6284
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发表时间：
2010-01-01
期刊：
影响因子：
1.7
通讯作者：
Harris, Julie M.
中科院分区：
文献类型：
--
作者：
Nefs, Harold T.;Harris, Julie M.
有两种方法可以检测立体深度的位移，即监测视差随时间的变化（CDOT）或监测眼间速度差（IOVD）。虽然之前的研究试图了解哪种线索对视觉系统最重要，但没有人设计出能在它们之间的相对效率方面进行比较的刺激。在这里，我们使用两帧运动和随机点噪声向视觉系统传递等效强度的CDOT和IOVD信息。使用三种随机点刺激，我们能够分离CDOT或IOVD或同时传递两者。传递CDOT或IOVD信号的点的比例可以变化，我们将识别阈值定义为检测位移方向（朝向或远离）所需的比例。(1)仅包含CDOT和同时包含CDOT和IOVD的刺激阈值相似，但只有一个参与者能够持续感知仅包含IOVD的刺激的位移。我们还研究了差异基准对歧视的影响。当位移越过参考平面时，效果最好，但仅含有CDOT的刺激与同时含有CDOT和IOVD的刺激无显著差异。当刺激被特别设计为提供等效的两帧运动或差异变化时，当IOVD是唯一的线索时，很少有参与者能够可靠地检测到位移。这挑战了IOVD参与两帧运动显示中位移方向识别的概念。
There are two ways to detect a displacement in stereoscopic depth, namely by monitoring the change in disparity over time (CDOT) or by monitoring the interocular velocity difference (IOVD). Though previous studies have attempted to understand which cue is most significant for the visual system, none has designed stimuli that provide a comparison in terms of relative efficiency between them. Here we used two-frame motion and random-dot noise to deliver equivalent strengths of CDOT and IOVD information to the visual system. Using three kinds of random-dot stimuli, we were able to isolate CDOT or IOVD or deliver both simultaneously. The proportion of dots delivering CDOT or IOVD signals could be varied, and we defined the discrimination threshold as the proportion needed to detect the direction of displacement (towards or away).((1)) Thresholds were similar for stimuli containing CDOT only, and containing both CDOT and IOVD, but only one participant was able to consistently perceive the displacement for stimuli containing only IOVD. We also investigated the effect of disparity pedestals on discrimination. Performance was best when the displacement crossed the reference plane, but was not significantly different for stimuli containing CDOT only and those containing both CDOT and IOVD. When stimuli are specifically designed to provide equivalent two-frame motion or disparity-change, few participants can reliably detect displacement when IOVD is the only cue. This challenges the notion that IOVD is involved in the discrimination of direction of displacement in two-frame motion displays.