Heeley D W, Timney B
Department of Psychology, University of St Andrews, Fife, Scotland, U.K.
Vision Res. 1989;29(9):1221-8. doi: 10.1016/0042-6989(89)90068-0.
Hirsch and Hylton (1984) have reported a meridional anisotropy for spatial frequency discrimination with a periodicity containing both square and hexagonal components. We measured the difference limen for spatial frequency for sine-wave gratings whose orientations varied over a 180 deg range and whose nominal spatial frequency varied between 2.5 and 10.0 c.deg.-1. Although some periodicity was evident at the lowest spatial frequency, it was not consistent between observers and it did not contain a hexagonal component. At the higher spatial frequencies there was no evidence for any meridional anisotropy.
赫希和希尔顿（1984年）报告了空间频率辨别方面的子午线各向异性，其周期性包含方形和六边形成分。我们测量了正弦波光栅空间频率的差别阈限，这些光栅的方向在180度范围内变化，其标称空间频率在2.5至10.0周/度-1之间变化。尽管在最低空间频率下有些周期性很明显，但观察者之间并不一致，且不包含六边形成分。在较高空间频率下，没有证据表明存在任何子午线各向异性。
