System and method for determining the three-dimensional location and orientation of identification markers

A method for tracking a handheld implement bearing a passive vectorized tracking marker permanently integrated with the implement, the marker having an identifiably unique rotationally asymmetric pattern of contrasting elements disposed on the marker, the method comprising:

• providing the handheld implement bearing a passive vectorized tracking marker permanently integrated with the implement;
• obtaining image information about the implement from a non-stereo optical tracker;
• obtaining from a database geometric information about the tracking marker;
• identifying the passive vectorized tracking marker on the basis of the unique pattern;
• determining within the image information the location of at least one pattern reference point of the passive vectorized tracking marker based on the geometric information, and
• determining within the image information the rotational orientation of the passive vectorized tracking marker based on the geometric information.

A method for monitoring changes in a handheld surgical implement in three dimensions relative to a surgical site, the method comprising:

• attaching a single passive vectorized scan-visible fiducial reference at a fiducial location proximate the surgical site;
• obtaining scan data by performing a scan of the surgical site and the fiducial location with the fiducial reference attached;
• obtaining from the scan data a three-dimensional spatial relationship between the fiducial reference and the surgical site;
• disposing in a field of view of a tracker a first passive vectorized tracking marker in fixed spatial relation with the fiducial reference;
• disposing in the field of view of the tracker the surgical implement comprising an interchangeable portion and an invariant portion, the invariant portion bearing a second passive vectorized marker permanently integrated with the invariant portion;
• obtaining image information of the field of view from the tracker;
• determining from the image information a three-dimensional location and orientation of the first tracking marker relative to the surgical site;
• identifying the interchangeable portion of the surgical implement in the image information;
• and
• determining from the image information and from the three-dimensional location and orientation of the first tracking marker relative to the surgical site the three-dimensional location and orientation of a working tip of the interchangeable portion of the surgical implement relative to the surgical site.