Patent ID: 6711290
Filing Date: 2004-03-23
Classification: G06K

Abstract:
A method for character recognition comprising the steps of:detecting a union of characters, preprocessing the union of characters, comparing the preprocessed union of characters with one or more template symbols, and applying a decision rule in order to either reject a template symbol or decide that the template symbol is included in the union of characters, the step of preprocessing the union of characters comprising the steps of: representing the union of characters as one or more curves, and parameterising said curve or curves, characterised in that the step of preprocessing the union of characters further comprises the step of forming, regarding various classes of transformations, one or more shapes for said curve or curves, wherein at least one of said classes of transformations is a subgroup of a group of all projective transformations, said subgroup comprising non-isometric transformations, and wherein said one or more shapes are invariant with regard to said classes of transformations, and the step of comparing comprises the steps of: forming one or more geometric proximity measures, wherein the step of forming one or more geometric proximity measures comprises selecting a scalar product that comprises derivatives of said curve or curves, and determining for every shape the values of said geometric proximity measures between said shape and correspondingly determined shapes for the template symbols, and the step of applying a decision rule comprises the step of: selecting one or more template symbols in consideration of said values.