Method of recognizing symbols differing from reference symbols by affine transformations.

摘要

An unknown symbol handwritten on a digitizing tablet is compared with symbols in a predefined "alphabet" or library of model symbols and the closest match chosen, taking into account all or some subset of affine transformations of the unknown symbol with respect to the alphabet symbols. A sequence of samples of the pen position is recorded while a symbol is being written on a digitizing tablet. The samples form a vector, which is then translated so that the centroid of the symbol lies at an origin. The comparison involves finding the minimum "distance" between the vector for the unknown symbol and any vector that can be obtained by linear transformations of the vectors for the model symbols. The model vector for which the minimum such distance can be obtained indicates the alphabet symbol the writer most likely intended to write. Alternative embodiments are described in which the types of linear transformations allowed are restricted.