Rotating Snakes Illusion-Quantitative Analysis Reveals a Region in Luminance Space With Opposite Illusory Rotation
Rotating Snakes Illusion-Quantitative Analysis Reveals a Region in Luminance Space With Opposite Illusory Rotation
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DOI：
10.1177/2041669517691779
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发表时间：
2017-01-01
期刊：
影响因子：
1.9
通讯作者：
Bach, Michael
中科院分区：
文献类型：
--
作者：
Atala-Gerard, Lea;Bach, Michael
旋转蛇错觉采用重复的不对称亮度步骤形成一个“蛇轮”的模式。在基本的亮度序列{黑色，深灰色，白色，浅灰色}中，编码为{0，g1，100，g2}，我们改变g1和g2，并通过调零来测量错觉强度：在物理旋转的“蛇轮”旁边进行扫视;观察者调整旋转，直到获得静止的错觉。观察者可靠地执行了对表面旋转的感知归零。根据Kitaoka的图像测量，（g1，g2）的典型设置大约为（20%，60%）。事实上，我们发现在旋转速度约为1度/秒的区域中存在明显的错觉（g1近似于{0%-25%}，g2近似于{20%-75%}）。令人惊讶的是，我们在（70%，95%）附近发现了第二个“岛”，它与错觉旋转方向相反，错觉较弱。我们对错觉强度的定量测量证实了标准蛇轮的最佳亮度选择，并且出乎意料地揭示了相反旋转的错觉。
The Rotating Snakes Illusion employs patterns with repetitive asymmetric luminance steps forming a "snake wheel.'' In the underlying luminance sequence {black, dark grey, white, light grey}, coded as {0, g1, 100, g2}, we varied g1 and g2 and measured illusion strength via nulling: Saccades were performed next to a "snake wheel'' that rotated physically; observers adjusted rotation until a stationary percept obtained. Observers performed the perceptual nulling of the seeming rotation reliably. Typical settings for (g1, g2), measured from images by Kitaoka, are around (20%, 60%). Indeed, we found a marked illusion in the region (g1 approximate to{0%-25%}, g2 approximate to{20%-75%}) with a rotation speed of approximate to 1 degrees/s. Surprisingly, we detected a second "island'' around (70%, 95%) with opposite direction of the illusory rotation and weaker illusion. Our quantitative measurements of illusion strength confirmed the optimal luminance choices of the standard snake wheel and, unexpectedly, revealed an opposite rotation illusion.