An apparatus and a concomitant method for rectification and recognition of
symbols (e.g., to correct for the effects of perspective distortion,
rotation and/or scale) in images of three-dimensional scenes is provided.
The present method locates a reference region lying in a common plane
with a symbol to be recognized, where the reference region represents an
image of a planar object having assumed (e.g., known or standard)
geometry and dimensions, along with at least four easily detectable
correspondence points within that geometry. An image of the common plane
is then rectified in three dimensions in accordance with the assumed
dimensions of the reference region in order to produce a transformed
(e.g., rectified) image of the symbol, which is significantly easier to
recognize than the original imaged appearance of the symbol using
existing recognition methods.