Full-field OCT technique for high speed event-based optical flow and particle tracking

Area of Science:

• Biophotonics
• Microfluidics
• Optical Imaging

Background:

• Accurate measurement of microparticle dynamics is crucial for understanding biological processes.
• Existing techniques often lack the temporal resolution required for real-time in vivo analysis.
• Optical Coherence Tomography (OCT) offers non-invasive imaging but can be limited by data acquisition speed.

Purpose of the Study:

• To develop and validate a novel method for real-time extraction of microparticle speed and density.
• To enhance the temporal resolution of full-field optical coherence tomography (FF-OCT) for microparticle analysis.
• To enable high-throughput, in vivo evaluation of microparticle dynamics, specifically erythrocyte behavior.

Main Methods:

• Integration of an asynchronous event-based camera with a full-field optical coherence tomography (FF-OCT) setup.
• Utilization of scene-driven acquisitions triggered by significant illuminance changes at 1μs precision.
• Implementation of an event-driven FF-OCT algorithm employing time-based optical flow computation directly on pixel events.
• Real-time estimation of velocity, direction, and density with reduced computational and data load.

Main Results:

• Demonstrated real-time extraction of microparticle speed and density at kHz frequencies.
• Achieved faster and more efficient performance compared to existing techniques for microparticles moving at 0.4 - 6.5 mm/s.
• Successfully reduced both computational and data load through the event-driven approach.

Conclusions:

• The developed method provides a significant advancement in real-time microparticle analysis.
• This technique offers high temporal resolution for evaluating microvascular erythrocyte dynamics in vivo.
• The approach is efficient and adaptable for various applications requiring fast microparticle tracking.