Cost reduction and quality preservation with digital scanner interfaces for optical coherence tomography

Area of Science:

• Biomedical Engineering
• Optical Imaging
• Instrumentation

Background:

• Traditional Optical Coherence Tomography (OCT) systems rely on expensive and noise-prone analog interfaces between engine and scanner components.
• Analog signals are susceptible to interference and require costly hardware for precise OCT scan pattern generation.

Purpose of the Study:

• To develop and evaluate a novel digital interface for OCT systems to overcome the limitations of conventional analog interfaces.
• To reduce the cost and improve the reliability of OCT system communication.

Main Methods:

• Implemented a digital interface using low-cost embedded microprocessors and custom PC software.
• Utilized USB for scan pattern download and position feedback, achieving a 50-kHz communication rate.
• Developed a custom printed circuit board (PCB) and released open-source firmware (vortex library).

Main Results:

• The digital interface reliably transmitted scan patterns and significantly reduced noise in position feedback signals compared to analog systems.
• Achieved equivalent spatial accuracy and comparable OCT image quality, with superior performance for complex scan patterns like spiral scanning.
• Demonstrated quantitative and qualitative equivalence to a conventional analog system that is an order of magnitude more expensive.

Conclusions:

• The developed digital interface offers a cost-effective and high-performance alternative to traditional analog interfaces in OCT systems.
• Open-sourcing the software, schematics, and design files enables the OCT community to adopt these improvements and cost savings.