1. A system for tracking the pose of an object displaceable in a coordinate reference frame, the system comprising: an optically-visible target pattern on an object being tracked, the pattern containing a plurality of 2D contrasting shapes located on a tile, the contrasting shapes being in an arrangement so as to uniquely differentiate the pattern from other patterns; a storage media containing stored data for a plurality of distinct patterns of contrasting shapes including, for each distinct pattern, the arrangement of contrasting shapes and locations of defined points in the pattern; an optical sensor assembly spaced apart from the object, the optical sensor assembly located and configured to capture images of at least a portion of the pattern, the sensor assembly including at least two cameras, each camera configured to capture a 2D image of the portion of the pattern, each 2D image being at a different viewing angle of the portion of the pattern than the other 2D image(s); and a processor configured to (i) retrieve the stored data for the plurality of distinct patterns of contrasting shapes, (ii) receive the 2D images from the sensor assembly, (iii) locate a plurality of defined points in each 2D image and determine a pair of basis vectors between each defined point and two of its adjacent defined points, (iv) determine a rectifying affine transform applicable to contrasting shapes in the pattern in each 2D image and predict grid locations in each 2D image, (v) determine a set of descriptors for each 2D image, each descriptor being determined based on coloring or shading of the contrasting shapes adjacent to each predicted grid location, and (vi) compare the descriptors to a library of descriptors in the stored data to select a specific pattern in the stored data that is closest to the pattern in each 2D image, and the processor configured to (vii) match defined points in one of the 2D images with corresponding defined points in the other 2D image and perform stereo triangulation with a location of the cameras to determine an estimate of a 3D location of each matched defined point, and (viii) calculate a second transform to convert the matched defined points to a target coordinate system to determine the pose of the object; wherein the processor is configured to use the rectifying affine transform to provide 2D translation, rotation, and scaling of the located defined points in the 2D images for correlating with 3D coordinates in the stored data for the identified distinct pattern.