Deep Reinforcement Learning Based System for Intraoperative Hyperspectral Video Autofocusing
This work addresses usability issues for hyperspectral imaging in surgical settings, offering an incremental improvement in autofocusing for domain-specific medical applications.
The authors tackled the problem of limited focal depth in intraoperative hyperspectral video imaging by integrating a focus-tunable lens and proposing a deep reinforcement learning-based autofocusing method, which significantly outperformed traditional techniques with a mean absolute focal error of 0.070±0.098 compared to 0.146±0.148.
Hyperspectral imaging (HSI) captures a greater level of spectral detail than traditional optical imaging, making it a potentially valuable intraoperative tool when precise tissue differentiation is essential. Hardware limitations of current optical systems used for handheld real-time video HSI result in a limited focal depth, thereby posing usability issues for integration of the technology into the operating room. This work integrates a focus-tunable liquid lens into a video HSI exoscope, and proposes novel video autofocusing methods based on deep reinforcement learning. A first-of-its-kind robotic focal-time scan was performed to create a realistic and reproducible testing dataset. We benchmarked our proposed autofocus algorithm against traditional policies, and found our novel approach to perform significantly ($p<0.05$) better than traditional techniques ($0.070\pm.098$ mean absolute focal error compared to $0.146\pm.148$). In addition, we performed a blinded usability trial by having two neurosurgeons compare the system with different autofocus policies, and found our novel approach to be the most favourable, making our system a desirable addition for intraoperative HSI.