部分相干成像系统分辨极限研究

Study on resolution of an imaging system with partially coherent light

摘要:

部分相干理论的引入丰富了光学成像分辨领域的研究,相较于理想情况下的完全相干和完全非相干光照明两点成像系统,部分相干成像系统的分辨率显著提升。本文设计了部分相干光照明两点成像系统,建立像面光强分布的数学模型,利用MATLAB仿真模拟不同空间相干性光源产生的辐射特性和两点间距对成像分辨的影响；并给出部分相干成像系统分辨极限的判定方法:当且仅当像面光强分布的峰值和谷值相等时可判定两点光源恰可分辨；以及不同相干度的光源照明成像系统分辨率的计算方法和差异。同时设计并搭建实验平台,实验结果验证了相干度分别为0、0.9和1.0时,成像分辨极限分别为1.0 mm、1.4 mm和1.5 mm,误差范围小于5%,说明实验结果与理论结果吻合。

Abstract:

The introduction of partial coherence theory has enriched the research in the field of optical imaging resolution.Compared with the two-point imaging system ideally illuminated by completely coherent and completely incoherent light,the resolution of the partially coherent imaging system has significantly improved.The two-point imaging system under illumination of partially coherent light is designed and the mathematical model of image intensity distribution through the imaging system is constructed. MATLAB is used to simulate the effects of the radiance characteristics of different spatial coherent light source and two-point separation on two-point resolution. The resolution of the partial coherent imaging system is determined:when the peak and valley values of the image intensity distribution are equal,the two overlapping points can be determined resolvable.The calculation methods and differences of imaging system resolution under partially coherent illumination are also presented.We design an imaging system experimental platform and the experimental results show that the imaging resolution are 1.0 mm, 1.4 mm,and 1.5 mm when the coherence degree are 0,0.9,and 1.0,respectively,and the error range is less than 5%.The experimental results are consistent with the theoretical results.