Hybrid Iterating-Averaging Low Photon Budget Gabor Holographic Microscopy

Area of Science:

• Biophysics
• Optical Microscopy
• Image Processing

Background:

• Quantitative phase imaging (QPI) faces challenges in achieving high-contrast, label-free imaging with minimal impact on live cells.
• Low photon budget (LPB) imaging reduces phototoxicity but introduces significant camera shot noise and quantification noise, hindering QPI.
• Digital in-line holographic microscopy (DIHM) offers robustness for LPB data, yet struggles with simultaneous twin image and shot noise suppression.

Purpose of the Study:

• To develop a novel algorithm for effective noise reduction in multiframe DIHM under low illumination intensities.
• To address the critical challenge of simultaneously minimizing twin image perturbation and camera shot noise in DIHM.
• To enable high-speed, photostimulation-free imaging of dynamic biological samples and optically thin specimens.

Main Methods:

• Introduction of the iterative Gabor averaging (IGA) algorithm, combining iterative phase retrieval with frame averaging.
• Leveraging an iterative process to reconstruct high-fidelity phase images while averaging camera shot noise across frames.
• Utilizing multiframe DIHM data acquired under low illumination conditions.

Main Results:

• Simulations demonstrated that IGA outperforms conventional methods in reconstruction accuracy, especially under high-noise conditions.
• Experimental validation showed IGA's efficacy in high-speed imaging of dynamic sperm cells and static phase targets under low illumination.
• The algorithm proved successful for optically thin samples, which typically produce low signal-to-noise holograms.

Conclusions:

• The IGA algorithm effectively suppresses twin image disturbance and shot noise in multiframe DIHM, enabling high-quality imaging under low photon budgets.
• IGA is a powerful tool for photostimulation-free, high-speed imaging of dynamic biological samples.
• This advancement enhances imaging capabilities for samples with extremely low optical thickness, with potential biomedical and environmental applications in low-light settings.