High-throughput space-time Fourier ptychography for motile microorganisms

Area of Science:

• Microscopy and Imaging Science
• Biophysics
• Computational Imaging

Background:

• High-fidelity live imaging is crucial for understanding dynamic biological processes.
• Existing methods struggle with motion blur and low temporal resolution, limiting studies of fast-evolving specimens.

Purpose of the Study:

• To develop and validate an optimized space-time Fourier ptychography (ST-FP) system for high-throughput, time-resolved quantitative phase imaging.
• To overcome limitations in photon budget, timing, and computational speed for imaging dynamic biological samples.

Main Methods:

• Developed a custom shift-register LED panel for flicker-free illumination, increasing effective irradiance by ~1100x.
• Implemented an auto-differentiable, GPU-accelerated complex-valued reconstruction framework with temporal regularization.
• Achieved a ~23x speedup in computational reconstruction time (CPU vs. GPU).

Main Results:

• Demonstrated stable imaging with exposure times as short as 800 μs.
• Achieved a ~45x improvement in space-bandwidth-time product (SBP-T) compared to previous ST-FP implementations.
• Successfully imaged live vinegar eels and brine shrimp at up to 260 Hz with uncontrolled motion.

Conclusions:

• The optimized ST-FP system significantly enhances the dynamic range and temporal resolution for live biological imaging.
• Motion-aware reconstruction enables detailed trajectory tracking and flow field analysis of dynamic biological behaviors.
• This technology pushes the boundaries of high-throughput Fourier ptychography for studying fast biological processes.