A system for precision guidance of surgical procedures on a patient is disclosed. Aspects of the system may include: a three-dimensional digital representation of a pre-procedural geometry of a relevant part of the patient, a three-dimensional digital representation of an intended post-procedural geometry of the relevant part of the patient including any implant or other structures intended to be attached to the patient, and a movable electro-optical (EO) camera mounted in a known position and orientation relative to a surgeon, such as a head mount. Further aspects of the system may include a first carrier comprising at least 3 targets to be observed by the EO camera, wherein the first carrier may be mounted in a known first position and first orientation relative to the relevant part of the patient, and a second carrier comprising at least 3 targets to be observed by the EO camera, wherein the second carrier may be mounted in a known second position and second orientation relative to an implant or surgical instrument. Embodiments of the system may include a computer for calculating, based on observations from the EO camera, relative positions of the first and second carriers and of the EO camera. Embodiments of the system may also include software, residing on the computer, configured to calculate a relevant projection of a digital representation of the patient to be displayed in order for the displayed projection to match with the surgeons current physical view of the patient.
