Quantitative Phase Imaging Camera With a Weak Diffuser

Frontiers in Physics

Qian Chen¹  Yao Fan³  Jiasong Sun³  Linpeng Lu³  Jialin Zhang³  Chao Zuo³ 

[1] Jiangsu Key Laboratory of Spectral Imaging and Intelligent Sense, Nanjing University of Science and Technology, Nanjing, China;School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing, China;Smart Computational Imaging Laboratory, Nanjing University of Science and Technology, Nanjing, China;

关键词: transport of intensity equation;    quantitative phase imaging;    microscopic imaging;    speckle imaging;    phase space;   

DOI  :  10.3389/fphy.2019.00077

来源: DOAJ

【 摘 要 】

We introduce the quantitative phase imaging camera with a weak diffuser (QPICWD) as an effective scheme of quantitative phase imaging (QPI) based on normal microscope platforms. The QPICWD is an independent compact camera measuring object induced phase delay under low-coherence quasi-monochromatic illumination by examining the deformation of the speckle intensity pattern. By interpreting the speckle deformation with an ensemble average of the geometric flow, we can obtain the high-resolution distortion field via the transport of intensity equation (TIE). Since the phase measured by TIE is the generalized phase of the partially coherent image, rather than the phase of the measured object, we analyze the effect of illumination coherence and imaging numerical aperture (NA) on the accuracy of phase retrieval, revealing that the sample's phase can be reliably reconstructed under the conditions that the coherence parameter (the ratio of illumination NA to objective NA) of the Köhler illumination is between 0.3 and 0.5. We present some applications for the proposed design involving nondestructive optical testing of microlens array with nanometric thickness and imaging of fixed and live unstained HeLa cells. Since the designed QPI camera does not require any modification of the widely available bright-field microscope or additional accessories for its use, it is expected to be applied by the broader communities of biology and medicine.

【 授权许可】

Unknown