Computational illumination for high-speed in vitro Fourier ptychographic microscopy
Files
First author draft
Date
2015-10-20
Authors
Tian, Lei
Liu, Ziji
Yeh, Li-Hao
Chen, Michael
Zhong, Jingshan
Waller, Laura
Version
OA Version
Citation
Lei Tian, Ziji Liu, Li-Hao Yeh, Michael Chen, Jingshan Zhong, Laura Waller. 2015. "Computational illumination for high-speed in vitro Fourier ptychographic microscopy." Optica, Volume 2, Issue 10, pp. 904 - 904.
Abstract
We demonstrate a new computational illumination technique that achieves large
space-bandwidth-time product, for quantitative phase imaging of unstained live samples
in vitro. Microscope lenses can have either large field of view (FOV) or high
resolution, not both. Fourier ptychographic microscopy (FPM) is a new computational
imaging technique that circumvents this limit by fusing information from
multiple images taken with different illumination angles. The result is a gigapixelscale
image having both wide FOV and high resolution, i.e. large space-bandwidth
product (SBP). FPM has enormous potential for revolutionizing microscopy and has
already found application in digital pathology. However, it suffers from long acquisition
times (on the order of minutes), limiting throughput. Faster capture times would
not only improve imaging speed, but also allow studies of live samples, where motion
artifacts degrade results. In contrast to fixed (e.g. pathology) slides, live samples
are continuously evolving at various spatial and temporal scales. Here, we present a
new source coding scheme, along with real-time hardware control, to achieve 0.8 NA
resolution across a 4× FOV with sub-second capture times. We propose an improved
algorithm and new initialization scheme, which allow robust phase reconstruction over
long time-lapse experiments. We present the first FPM results for both growing and
confluent in vitro cell cultures, capturing videos of subcellular dynamical phenomena
in popular cell lines undergoing division and migration. Our method opens up FPM
to applications with live samples, for observing rare events in both space and time.