MONOCULAR DISCRIMINATION OF THE DIRECTION OF MOTION IN-DEPTH
MONOCULAR DISCRIMINATION OF THE DIRECTION OF MOTION IN-DEPTH
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DOI：
10.1016/0042-6989(94)90329-8
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发表时间：
1994-01-01
期刊：
影响因子：
1.8
通讯作者：
KAUSHAL, S
中科院分区：
文献类型：
--
作者：
REGAN, D;KAUSHAL, S
单目观察的刚性球体的深度运动方向可以根据球体的中心将错过观察眼睛的瞳孔中心的距离来量化。如果我们将该距离表示为ns（其中s是球体的半径，n是比例因子），则n近似于物体视网膜图像的平移速度（dphi/dt）和扩展速率（dtheta/dt）之间的比率（dphi/dt）/（dtheta/dt）。要单独使用这种单眼信息作为运动动作的基础，就必须事先了解s。（然而，s的值可从双目信息获得，因此球体中心将错过眼睛的距离原则上仅可从视网膜图像信息获得，并且特别地，不知道对象的大小或距眼睛的距离。我们测量了单眼观看的模拟物体在深度方向上的运动的刚刚可辨别的差异。测量了水平、垂直和两个斜子午线内的轨迹。视网膜图像的平移速度作为一个可靠的线索，通过随机改变模拟对象的速度在试验的基础上，在深度的运动方向被删除。平移运动的方向也被删除作为一个可靠的线索。对于我们的7个受试者，模拟运动方向的辨别阈值范围为0.03至0.12度，并且在研究范围内相对于视线的运动方向没有明显变化，也不取决于轨迹是否包含在水平、垂直或倾斜子午线内。我们的结论是，受试者能够单眼辨别的差异，在深度的运动方向，即使在视网膜图像的平移的方向和速度被删除作为可靠的线索。
The direction of motion in depth of a monocularly-viewed rigid sphere can be quantified in terms of the distance by which the sphere's centre will miss the centre of the pupil of the observing eye. If we express this distance as ns (where s is the sphere's radius and n is a scaling factor), then n approximates the ratio (dphi/dt)/(dtheta/dt) between the translational velocity (dphi/dt) and the rate of expansion (dtheta/dt) of the object's retinal image. To use this monocular information alone as a basis for motor action, prior knowledge of s would be necessary. (However, the value of s is available from binocular information, so that the distance by which the sphere's centre would miss the eye is, in principle, available from retinal image information alone and, in particular, without knowing the object's size or distance from the eye.) We measured the just-discriminable difference in the direction of motion in depth for a monocularly-viewed simulated object. Thresholds were measured for trajectories contained within the horizontal, vertical and two oblique meridia. The translational speed of the retinal image was removed as a reliable cue to the direction of motion in depth by randomly varying the simulated object's speed on a trial to trial basis. The direction of translational motion was also removed as a reliable cue. Discrimination threshold for the simulated direction of motion ranged from 0.03 to 0.12 deg for our seven subjects, and did not vary appreciably with the direction of motion relative to the line of sight over the range investigated, nor did it depend on whether trajectory was contained within the horizontal, vertical or oblique meridia. We conclude that subjects are able monocularly to discriminate differences in the direction of motion in depth, even when both the direction and speed of retinal image translation are removed as reliable cues.