Optical word recognition by examination of word shape
AssigneeXerox Corporation
InventorsDaniel P. Huttenlocher, Michael J. Hopcroft
Life of this patent
Estimating the term…
Abstract
A method for reducing an image of a character or word string to one or more one dimensional signals, including the steps of determining page orientation, isolating character strings from adjacent character strings, establishing a set of references with respect to which measurements about the character string may be made, and deriving a plurality of measurements with respect to the references in terms of one dimensional signal, amenable to identification processing techniques.
Claims13
A method of recognizing a string of symbols in data defining an image, comprising the steps of:
- a) detecting in a set of image signals representing an image, a discrete symbol string in an image wherein symbols strings are made up of a plurality of discrete symbols, and image data representing a symbol string in the image data distinguishes symbol-to-symbol spacing from symbol string-to-symbol string spacing;
- b) representing the image data of one such symbol string as at least one, one-dimensional signal, said step of representing image data of one such symbol string including the substeps of:
- identifying a reference with respect to which a shape signal will be derived for the symbol string;
- deriving a set of measurements from the reference with respect to the image data forming the symbol string representing the set of measurements as a curve;
- and
- for a selected portion of the curve, representing that portion as a one dimensional signal f(t) derived with respect to the reference;
- and
- c) comparing said representative signal of the symbol string with a representative signal of a second symbol string.
A method of recognizing a string of symbols forming a word object within data defining an image, comprising the steps of:
- a) identifying a discrete symbol string in the data defining the image wherein symbols strings are made up of a plurality of discrete symbols, and image data representing a symbol string in the image data distinguishes symbol-to-symbol spacing from symbol string-to-symbol string spacing;
- b) deriving a signal representative of at least a portion of the shape of the symbol string, wherein the step of representing image data of one such symbol string includes the substeps of:
- identifying a first reference with respect to which a shape signal will be derived for the symbol string;
- deriving a set of measurements from the reference with respect to the image data forming the symbol string;
- representing the set of measurements as a curve;
- and
- for a selected portion of the curve, representing that portion as a one dimensional signal f(t) derived with respect to the reference;
- identifying a second reference with respect to which a shape signal will be derived for the symbol string;
- deriving a second set of measurements from the second reference with respect to the image data forming the second symbol string;
- representing the second set of measurements as a second curve;
- and
- for a selected portion of the second curve, representing that portion as a one dimensional signal fit) derived with respect to the second reference;
- c) comparing said derived signal to at least one other known signal for determination of equivalence therewith;
- and
- d) indicating recognition based on said comparison.
Dependencies are inferred from the claim text.