Virtual Hall sensor triggered multi-MHz endoscopic OCT imaging for stable real-time visualization

Awanish Pratap Singh, Madita Göb, Martin Ahrens, Tim Eixmann, Berenice Schulte, Hinnerk Schulz-Hildebrandt, Gereon Hüttmann, Mark Ellrichmann, Robert Huber, Maik Rahlves


Circumferential scanning in endoscopic imaging is crucial across various disciplines, and optical coherence tomography (OCT) is often the preferred choice due to its high-speed, high-resolution, and micron-scale imaging capabilities. Moreover, real-time and high-speed 3D endoscopy is a pivotal technology for medical screening and precise surgical guidance, among other applications. However, challenges such as image jitter and non-uniform rotational distortion (NURD) are persistent obstacles that hinder real-time visualization during high-speed OCT procedures. To address this issue, we developed an innovative, low-cost endoscope that employs a brushless DC motor for scanning, and a sensorless technique for triggering and synchronizing OCT imaging with the scanning motor. This sensorless approach uses the motor’s electrical feedback (back electromotive force, BEMF) as a virtual Hall sensor to initiate OCT image acquisition and synchronize it with a Fourier Domain Mode-Locked (FDML)-based Megahertz OCT system. Notably, the implementation of BEMF-triggered OCT has led to a substantial reduction in image jitter and NURD (<4 mrad), thereby opening up a new window for real-time visualization capabilities. This approach suggests potential benefits across various applications, aiming to provide a more accurate, deployable, and cost-effective solution. Subsequent studies can explore the adaptability of this system to specific clinical scenarios and its performance under practical endoscopic conditions.
Original languageEnglish
JournalOpt. Express
Issue number4
Pages (from-to)5809-5825
Number of pages17
Publication statusPublished - 01.02.2024

Research Areas and Centers

  • Academic Focus: Biomedical Engineering

DFG Research Classification Scheme

  • 205-32 Medical Physics, Biomedical Engineering

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