Spatial contrast sensitivity and grating acuity of barn owls
Spatial contrast sensitivity and grating acuity of barn owls
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DOI：
10.1167/9.7.13
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发表时间：
2009-01-01
影响因子：
1.8
通讯作者：
Wagner, Hermann
中科院分区：
文献类型：
--
作者：
Harmening, Wolf M.;Nikolay, Petra;Wagner, Hermann
谷仓猫头鹰（Tyto alba pratincola）的眼睛显示出的像差非常小，因此具有出色的光学质量。在一系列行为实验中，我们测试了这种可能有益的特征是否也反映在该物种的感知水平上。作为视觉表现的基本指标，我们利用心理物理学技术测量了两只仓鸮的空间对比敏感度函数（CSF）和光栅敏锐度。刺激亮度为2.7 cd/m(2)。此处发现的 CSF 呈现典型的带限、倒 U 形函数，在 1 周期/度的空间频率下具有 8-19 的低最大对比灵敏度。光栅锐度根据 CSF 高频截止估计并产生 3.0-3.7 周期/度。在第二个实验中，对比度保持恒定，空间频率变化，直接测量光栅锐度（2.6-4.0 cyc/deg）。这些结果使仓鸮处于鸟类视力范围的极低端，并表明视觉分辨率和灵敏度不能仅通过光学考虑来预测。
The eyes of barn owls (Tyto alba pratincola) display very little aberrations, and have thus excellent optical quality. In a series of behavioral experiments, we tested whether this presumably beneficial feature is also reflected at a perceptual level in this species. As fundamental indicators for visual performance, the spatial contrast sensitivity function (CSF) and grating acuity were measured in two barn owls with psychophysical techniques. Stimulus luminance was 2.7 cd/m(2). The CSF found here renders the typical band-limited, inverted U-shaped function, with a low maximum contrast sensitivity of 8-19 at a spatial frequency of 1 cyc/deg. Grating acuity was estimated from the CSF high frequency cut-off and yielded 3.0-3.7 cyc/deg. In a second experiment, in which contrast was held constant and spatial frequency was varied, grating acuity was measured directly (2.6-4.0 cyc/deg). These results put barn owls at the very low end of the visual acuity spectrum of birds, and demonstrate that visual resolution and sensitivity cannot be predicted by optical considerations alone.