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

A method for tracking an item bearing at least one pattern tag, the pattern tag bearing a rotationally asymmetric pattern having a plurality of contrasting portions, at least one of the plurality of contrasting portions having a perimeter with a polygonal shape, the method comprising the steps of:

• obtaining from a tracker image information about the at least one pattern tag;
• obtaining from a database geometric information about the at least one pattern tag, the geometric information comprising a mathematical description of a polygonal perimeter of the at least one contrasting portion of the at least one pattern tag;
• determining within the image information a three-dimensional location of at least one pattern reference point of the at least one pattern tag based on the mathematical description of the polygonal perimeter, and
• determining within the image information a three-dimensional rotational orientation of the at least one pattern tag based on the geometric information.

A surgical monitoring system comprising

• a tracker for obtaining image information of a surgical site;
• a fiducial reference configured for removably attaching to a location proximate the surgical site;
• a tracking marker in fixed three-dimensional spatial relationship with the fiducial reference and observable by the tracker, the tracking marker bearing at least one pattern comprising a plurality of contrasting portions and at least one of the contrasting portions having a perimeter with a polygonal shape, the tracking marker having a shape with a surface extending in three dimensions;
• and
• a controller configured to spatially relate image information to previously obtained scan data, the controller having a processor and a memory, the controller in communication with the tracker, the memory storing software that when executed by the processor determines the three-dimensional location and orientation of the fiducial reference by relating the image information to the scan data on the basis of the polygonal shape.

A method for tracking an item bearing a pattern tag having at least one unique rotationally asymmetric pattern, the method comprising the steps of:

• obtaining image information from a tracker about the at least one pattern tag;
• identifying the at least one pattern tag within the image information on the basis of its unique pattern;
• obtaining from a database geometric information about the at least one pattern tag, the geometric information comprising a mathematical description of a polygonal perimeter of at least one contrasting portion of the at least one pattern tag;
• determining from the image information the location of at least one pattern reference point of the at least one pattern tag based on the mathematical description of the polygonal perimeter;
• and
• determining from the image information the three-dimensional rotational orientation of the at least one pattern tag based on the geometric information and the at least one pattern reference point.

A method for tracking the location and rotational orientation of an item comprising the steps of:

• attaching to the item a tracking marker bearing a rotationally asymmetric pattern of contrasting portions, at least a section of the perimeter of at least one contrasting portion of the at least one pattern tag having a mathematical description;
• obtaining image information from a tracker about the at least one pattern tag;
• obtaining geometric information from a database about the at least one pattern tag, the geometric information comprising a mathematical description of a polygonal perimeter of at the least one contrasting portion of the at least one pattern tag;
• determining from the image information the three-dimensional location of at least one pattern reference point of the at least one pattern tag based on the geometric information;
• and
• determining within the image information the three-dimensional rotational orientation of the at least one pattern tag based on the mathematical description of the polygonal perimeter.