A portable projection mapping device for medical augmented reality in single-stage cranioplasty

We introduce a portable projection mapping device (PPMD) for extracting and projecting implant geometric data in single-stage cranioplasty surgery. Our system consists of a real-time tracking device, which tracks the reference markers fixed on the skull, and a digitizing probe for localizing the contour of the cranial defect for modifying the oversized customized cranial implant (CCI). The feature points on the surface of the skull are registered to the reconstructed surface model of the skull obtained from CT image. The CT model is then projected on the surface of the skull. The digitizer is used to outline the geometry of the skull resection with sub-millimeter tracking accuracy. The proposed PPMD and its associated pipeline enable intraoperative cranial implant modification with image feedback to surgeons for the very first time. Our proposed PPMD system, an inexpensive device can also be used for other medical augmented reality applications, especially when direct projection mapping is preferred over the use of wearable head-mounted displays.