Krug Sarah E, Rabb David J
J Opt Soc Am A Opt Image Sci Vis. 2017 May 1;34(5):A47-A55. doi: 10.1364/JOSAA.34.000A47.
A digital piston phase correction method is presented for partially coherent synthesis with active or passive illumination. An anamorphic pupil relay causes a linear shift of a two subaperture array between the entrance and exit pupils. This shift separates the subapertures' cross- and auto-correlations while retaining their common spatial frequency information. Digital analysis of these common frequencies finds the separation distance and piston phase error of the cross-correlations and enables lossless correction of phase error. Corrected images are diffraction limited. Partial coherence affects the contrast of each spatial frequency, causing optical path difference tolerances to relax as system bandwidth decreases.
提出了一种用于主动或被动照明的部分相干合成的数字活塞相位校正方法。一个变形光瞳中继器会导致两个子孔径阵列在入射光瞳和出射光瞳之间产生线性位移。这种位移分离了子孔径的互相关和自相关，同时保留了它们共同的空间频率信息。对这些共同频率进行数字分析可找到互相关的分离距离和活塞相位误差，并能实现相位误差的无损校正。校正后的图像受衍射限制。部分相干会影响每个空间频率的对比度，随着系统带宽减小，会使光程差容限放宽。
