Leroux C, Dainty C
Applied Optics Group, School of Physics, National University of Ireland, Galway.
Opt Express. 2010 Jan 18;18(2):1197-206. doi: 10.1364/OE.18.001197.
Most Shack-Hartmann based aberrometers use infrared light, for the comfort of the patients. A large amount of the light that is scattered from the retinal layers is recorded by the detector as background, from which it is not trivial to estimate the centroid of the Shack-Hartmann spot. For a centroiding algorithm, background light can lead to a systematic bias of the centroid positions towards the centre of the software window. We implement a matched filter algorithm for the estimation of the centroid positions of the Shack-Hartmann spots recorded by our aberrometer. We briefly present the performance of our algorithm, and recall the well-known robustness of the matched filter algorithm to background light. Using data collected on 5 human eyes, we parameterise a simple and fast centroiding algorithm and reduce the difference between the two algorithms down to a mean residual wavefront of 0.02 microm rms.
大多数基于夏克-哈特曼的像差仪使用红外光，以照顾患者的舒适度。从视网膜层散射的大量光线被探测器记录为背景光，要从这些背景光中估计夏克-哈特曼光斑的质心并非易事。对于质心定位算法而言，背景光可能会导致质心位置朝着软件窗口中心产生系统性偏差。我们为自己的像差仪所记录的夏克-哈特曼光斑质心位置估计实现了一种匹配滤波算法。我们简要介绍了该算法的性能，并回顾了匹配滤波算法对背景光的众所周知的鲁棒性。利用在5只人眼上收集的数据，我们对一种简单快速的质心定位算法进行了参数化，并将两种算法之间的差异减小到均方根值为0.02微米的平均残余波前。
