摘　要：活体细胞成像中，折射率和厚度分布的检测结果一直是细胞变异和形态分析中的重要参数。在光学相位成像中，由于细胞折射率和厚度的耦合效应，细胞的折射率不能直接被测量到，因此，细胞折射率和厚度解耦方法的研究一直是该领域研究的一个热点。对此,本文以血细胞为研究对象，基于免标三维相位成像信息，建立双波长相移方程，通过三维相位成像下的双波长相位信息分布特征和梯度分布特征分析，利用细胞介质的色散特性，得到了双波长相位分布函数表示下的均质和有核非均质样品的折射率以及厚度解耦的数学解。通过单介质模型和外胞类球形有核式模型的仿真实验，得到了折射率和外胞及内核厚度分布的结果，误差分析表明其具有较高的精准性，由此验证了本文方法的正确性。本文方法可对均质细胞（如血红细胞）和外胞类球形有核细胞（如白细胞）进行折射率和厚度分布的解耦，由此可为血细胞质量检测和亚类识别方法的研究提供一种新思路。
关键词：相位显微成像；血细胞；折射率；厚度分布；解耦方法
中图分类号：O436                             文献标志码：A DOI：10.3969/j.issn.1007-7146.2022.02.006

Abstract: In the imaging of living cells, the detection results of refractive index and thickness distribution have always been important parameters in the analysis of cell variation and morphology. In optical phase imaging, due to the coupling effect of RI and thickness of cells, the RI of cells cannot be directly measured, hence the decoupling method of RI and thickness of cells has always been a hot topic in this field. This article focuses on the subject of blood cells based on the free lable three-dimensional phase imaging information to establish dual wavelength phase shift equation, and analyse it by the three-dimensional phase imaging under dual wavelength phase information distribution and gradient distribution characteristics and obtain mathematical result of decoupling of the RI and thickness of homogeneous and nucleated heterogeneous samples by the dual wavelength phase distribution function. The RI and the thickness distribution of the outer cell and the inner core are obtained through the simulation experiments of the single medium model and the spherical outer cell kernel model. The error analysis shows that the method is highly accurate, which verifies the correctness of the method of this article. The proposed method can be used to decouple the RI and thickness distribution of red blood cells and five subgroups of white blood cells, which can provide a new method for the analysis of blood cell abnormality and cell morphology.
Key words: phase microscopic imaging; blood cell; refractive index; thickness distribution; decoupling method
（Acta Laser Biology Sinica, 2022, 31(2): 134-141）