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Proceedings Paper

Computational diffraction tomographic microscopy with transport of intensity equation using a light-emitting diode array
Author(s): Jiaji Li; Qian Chen; Jialin Zhang; Chao Zuo
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Paper Abstract

Optical diffraction tomography (ODT) is an effective label-free technique for quantitatively refractive index imaging, which enables long-term monitoring of the internal three-dimensional (3D) structures and molecular composition of biological cells with minimal perturbation. However, existing optical tomographic methods generally rely on interferometric configuration for phase measurement and sophisticated mechanical systems for sample rotation or beam scanning. Thereby, the measurement is suspect to phase error coming from the coherent speckle, environmental vibrations, and mechanical error during data acquisition process. To overcome these limitations, we present a new ODT technique based on non-interferometric phase retrieval and programmable illumination emitting from a light-emitting diode (LED) array. The experimental system is built based on a traditional bright field microscope, with the light source replaced by a programmable LED array, which provides angle-variable quasi-monochromatic illumination with an angular coverage of ±37 degrees in both x and y directions (corresponding to an illumination numerical aperture of ∼ 0.6). Transport of intensity equation (TIE) is utilized to recover the phase at different illumination angles, and the refractive index distribution is reconstructed based on the ODT framework under first Rytov approximation. The missing-cone problem in ODT is addressed by using the iterative non-negative constraint algorithm, and the misalignment of the LED array is further numerically corrected to improve the accuracy of refractive index quantification. Experiments on polystyrene beads and thick biological specimens show that the proposed approach allows accurate refractive index reconstruction while greatly reduced the system complexity and environmental sensitivity compared to conventional interferometric ODT approaches.

Paper Details

Date Published: 24 October 2017
PDF: 4 pages
Proc. SPIE 10458, AOPC 2017: 3D Measurement Technology for Intelligent Manufacturing, 104580O (24 October 2017); doi: 10.1117/12.2283390
Show Author Affiliations
Jiaji Li, Nanjing Univ. of Science and Technology (China)
Qian Chen, Nanjing Univ. of Science and Technology (China)
Jialin Zhang, Nanjing Univ. of Science and Technology (China)
Chao Zuo, Nanjing Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 10458:
AOPC 2017: 3D Measurement Technology for Intelligent Manufacturing
Wolfgang Osten; Anand Krishna Asundi; Huijie Zhao, Editor(s)

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