Optical coherence tomography using physical domain data compression to achieve MHz A-scan rates

Area of Science:

• Biomedical Optics
• Medical Imaging
• Optical Engineering

Background:

• Optical coherence tomography (OCT) generates large datasets, requiring high-speed acquisition and processing.
• Existing OCT systems push A-scan rates to the MHz regime using time-stretch methods, but are limited by analog-to-digital converter (ADC) bandwidth and data volume.

Purpose of the Study:

• To develop a compressed sensing OCT (CS-OCT) system for high-speed volumetric imaging.
• To implement data compression in the physical domain before digitization to reduce ADC requirements and data handling.
• To evaluate the impact of compression and speed on image quality.

Main Methods:

• Utilized a mode-locked laser (MLL) source, electro-optic modulation, and optical dispersion for compressed sensing.
• Employed a compressive A-scan optical sampling approach combined with the joint sparsity of C-scan data.
• Achieved acquisition speeds from 14.4-MHz to 144-MHz using a sub-Nyquist 1.44 Gsample/sec ADC.

Main Results:

• Demonstrated real-time compressed measurements of OCT signals via analog domain compression.
• Enabled the use of lower bandwidth ADCs, reducing system cost and data capacity needs.
• Achieved significantly higher A-scan acquisition speeds compared to traditional Nyquist sampling methods.

Conclusions:

• CS-OCT offers a viable approach for high-speed, high-dimensional volumetric imaging.
• Analog domain compression in CS-OCT mitigates limitations of ADC bandwidth and data volume.
• The CS-OCT system shows promise for advancing OCT imaging capabilities in terms of speed and efficiency.