Noise and sensitivity in optical coherence tomography based vibrometry

Area of Science:

• Biomedical Optics
• Vibrational Analysis
• Medical Imaging

Background:

• Optical coherence tomography (OCT) offers high phase sensitivity for measuring vibrations.
• Applications include sensing vibratory responses in organ systems like the middle and inner ear.
• Frequency domain analysis enables picometer-level vibration sensitivity across a broad frequency range.

Purpose of the Study:

• To investigate the limitations of frequency domain vibratory sensitivity in OCT.
• To analyze the impact of phase noise statistics on estimating vibratory amplitude and phase.
• To propose a sensitivity metric for OCT-based vibration measurements.

Main Methods:

• Theoretical analysis of noise statistics under Rayleigh (low signal-to-noise ratio) and Normal (high signal-to-noise ratio) distribution limits.
• Simulations to explore theoretical findings.
• Experimental verification using a swept-laser OCT system and a piezoelectric element.

Main Results:

• Additive noise significantly impacts the limits of frequency domain vibratory sensitivity.
• Phase noise statistics critically influence the accuracy of vibratory amplitude and phase estimation.
• A novel sensitivity metric based on the 98% confidence interval for the Rayleigh distribution was proposed.

Conclusions:

• Understanding noise statistics is crucial for optimizing OCT-based vibratory measurements.
• The proposed sensitivity metric provides a quantifiable measure for system performance.
• This work advances the application of OCT for precise vibratory analysis in biological systems.