Stereomotion speed perception: Contributions from both changing disparity and interocular velocity difference over a range of relative disparities
Stereomotion speed perception: Contributions from both changing disparity and interocular velocity difference over a range of relative disparities
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DOI：
10.1167/4.12.6
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发表时间：
2004-01-01
影响因子：
1.8
通讯作者：
Stone, LS
中科院分区：
文献类型：
--
作者：
Brooks, KR;Stone, LS
通过测量立体运动速度辨别力和静态视差辨别力(立体视敏度)，研究了两种双眼线索在深度变化视差(CD)和眼间速度差(IOVD)中的作用。对随机点立体图(RDS)和时间上不相关的动态随机点立体图(DRDS)的速度辨别阈值进行了评估，在相对视差基准点分别为-19、0和+19弧分时。RDS刺激包含CD和IOVD线索，而DRDS刺激仅携带CD信息。平均而言，DRDS的阈值比RDS刺激的阈值高1.7倍，而相对差异基数没有明显的影响。接近和后退目标的结果是相似的。刺激持续时间的变化对阈值没有显著影响，刺激位移和感知速度之间也没有观察到的相关性，证实了受试者在每种情况下都对刺激速度做出了反应。立体视觉对我们的RDS和DRDS刺激同样有好处，这表明对于这些刺激，立体运动速度辨别性能的差异并不是由于视差线索的精度的任何差异。此外，当我们通过独立操纵单眼半图像的速度和方向来改变立体运动刺激轨迹时，感觉到的立体运动速度仍然准确。这一发现与基于单眼半图像运动的特性或单眼速度的任何特别组合的反应策略不一致。我们的结论是，尽管受试者能够仅根据CD信息可靠地区分立体运动速度，但IOVD为立体运动速度知觉提供了精确的额外线索。
The role of two binocular cues to motion in depth - changing disparity (CD) and interocular velocity difference (IOVD) - was investigated by measuring stereomotion speed discrimination and static disparity discrimination performance (stereoacuity). Speed discrimination thresholds were assessed both for random dot stereograms (RDS), and for their temporally uncorrelated equivalents, dynamic random dot stereograms (DRDS), at relative disparity pedestals of - 19, 0, and +19 arcmin. While RDS stimuli contain both CD and IOVD cues, DRDS stimuli carry only CD information. On average, thresholds were a factor of 1.7 higher for DRDS than for RDS stimuli with no clear effect of relative disparity pedestal. Results were similar for approaching and receding targets. Variations in stimulus duration had no significant effect on thresholds, and there was no observed correlation between stimulus displacement and perceived speed, confirming that subjects responded to stimulus speed in each condition. Stereoacuity was equally good for our RDS and DRDS stimuli, showing that the difference in stereomotion speed discrimination performance for these stimuli was not due to any difference in the precision of the disparity cue. In addition, when we altered stereomotion stimulus trajectory by independently manipulating the speeds and directions of its monocular half-images, perceived stereomotion speed remained accurate. This finding is inconsistent with response strategies based on properties of either monocular half-image motion, or any ad hoc combination of the monocular speeds. We conclude that although subjects are able to discriminate stereomotion speed reliably on the basis of CD information alone, IOVD provides a precise additional cue to stereomotion speed perception.