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Proceedings Paper

High-throughput and field-portable ptychographic lensless on-chip microscopy based on translated pattern modulation
Author(s): Shaowei Jiang; Zichao Bian; Jiakai Zhu; Pengming Song; Chengfei Guo; He Zhang; Ruihai Wang; Guoan Zheng
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Paper Abstract

We discuss two compact, cost-effective, and field-portable ptychographic lensless imaging platforms for quantitative microscopy. In the first implementation, we use a low-cost galvo scanner to rapidly scan an unknown laser speckle pattern on the object. To address the positioning repeatability and accuracy issues, we directly recover the positional shifts of the speckle pattern based on the phase correlation of the captured images. To bypass the resolution limit set by the imager pixel size, we employ a sub-sampled ptychographic phase retrieval process to recover the complex object. In the second implementation, we place a thin diffuser in between the object and the image sensor for light wave modulation. By blindly scanning the unknown diffuser to different x-y positions, we acquire a sequence of modulated intensity images for quantitative object recovery. Different from previous ptychographic implementations, we employ a unit magnification configuration with a Fresnel number of ~50,000, which is orders of magnitude higher than previous ptychographic setups. The unit magnification configuration allows us to have the entire sensor area, 6.4 mm by 4.6 mm, as the imaging field of view. The ultra-high Fresnel number enables us to directly recover the positional shift of the diffuser in the phase retrieval process. In this second implementation, we use a low-cost, DIY scanning stage to perform blind diffuser modulation. We further employ an up-sampling phase retrieval scheme to bypass the resolution limit set by the imager pixel size and demonstrate a half-pitch resolution of 0.78 µm. For both implementations, we validate the imaging performance via various biological samples. The reported platforms provide cost-effective and turnkey solutions for large field-of-view, high-resolution, and quantitative on-chip microscopy. They are adaptable for a wide range of point-of-care-, global-health-, and telemedicine-related applications.

Paper Details

Date Published: 20 February 2020
PDF: 9 pages
Proc. SPIE 11250, High-Speed Biomedical Imaging and Spectroscopy V, 112500E (20 February 2020); doi: 10.1117/12.2546994
Show Author Affiliations
Shaowei Jiang, Univ. of Connecticut (United States)
Zichao Bian, Univ. of Connecticut (United States)
Jiakai Zhu, Univ. of Connecticut (United States)
Pengming Song, Univ. of Connecticut (United States)
Chengfei Guo, Univ. of Connecticut (United States)
He Zhang, Univ. of Connecticut (United States)
Ruihai Wang, Univ. of Connecticut (United States)
Guoan Zheng, Univ. of Connecticut (United States)

Published in SPIE Proceedings Vol. 11250:
High-Speed Biomedical Imaging and Spectroscopy V
Kevin K. Tsia; Keisuke Goda, Editor(s)

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