Deeley R J, Drasdo N, Charman W N
Department of Vision Sciences, Aston University, Birmingham, UK.
Ophthalmic Physiol Opt. 1991 Jan;11(1):91-3.
The ocular modulation transfer function (MTF) has an important role in many investigations into human vision. It can be approximated by the equation MT = exp [-(SF/SFc)n], where MT, SF, SFc and n are the modulation transfer, spatial frequency, frequency constant and MTF index respectively. In a theoretical study, the parameters n and SFc were determined by a mathematical method from previously published data. A general equation was deduced expressing the MTF as a function of pupil size for diameters of 1.5-7.5 mm. For pupil diameters below 1.5 mm different equations providing MTFs as a function of pupil diameter have been produced. These are based on the assumption that for these pupil diameters diffraction and retinal scatter determine the optical degradation. The use of these models is described in studies on spatial vision, where they have widespread applications and the effects of optical degradation are frequently neglected.
眼调制传递函数（MTF）在许多关于人类视觉的研究中具有重要作用。它可以用方程MT = exp [-(SF/SFc)n]来近似，其中MT、SF、SFc和n分别是调制传递、空间频率、频率常数和MTF指数。在一项理论研究中，参数n和SFc是通过数学方法根据先前发表的数据确定的。推导了一个通用方程，将MTF表示为直径为1.5 - 7.5毫米的瞳孔大小的函数。对于直径小于1.5毫米的瞳孔，已经得出了不同的将MTF表示为瞳孔直径函数的方程。这些方程基于这样的假设，即对于这些瞳孔直径，衍射和视网膜散射决定了光学退化。这些模型的应用在空间视觉研究中有所描述，在这些研究中它们有广泛的应用，并且光学退化的影响常常被忽视。
