Systems and methods for surgical navigation, including image-guided navigation of a patient's head

Systems, methods and devices are described herein for performing a navigated surgical procedure involving a patient's anatomy in sterile and non-sterile surgical environments. A camera may be used to determine a registration of the camera coordinate-frame to the patient anatomy or optionally a tracker in relation to the patient anatomy. A drape may be applied to permit use in a sterile surgical environment. The camera may be moved from its original position to enable access to patient anatomy while maintaining a registration of the camera coordinate-frame with the patient anatomy. Alternatively, the camera may be used in a hand-held or head-mounted manner. A visualization of the patient anatomy may be displayed on a computing unit, with visualization reference planes defined by the pose of an instrument or the camera. The visualization may be presented on a display of a computing unit or as part of a head mounted augmented reality system.