Accession Number:

ADA229036

Title:

A Whole Word and Number Reading Machine Based on Two Dimensional Low Frequency Fourier Transforms

Descriptive Note:

Doctoral thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1990-12-01

Pagination or Media Count:

135.0

Abstract:

The Fourier transform is investigated as a means for developing an optical reader capable of reading a large vocabulary without segmenting the image of a word into individual characters. The reader is capable of reading printed and cursive font styles, is scale invariant, and is substantially insensitive to noise. The image of a particular word is treated as a single symbol the two dimensional low frequency Fourier coefficients assuming n coefficients are calculated define the words location on an n dimensional hypersphere of unit radius. The distance between individual locations words categorizes similar and dissimilar words. The smaller the distance, the more similar images are. Multiple images of a word using various font styles form a unique cluster on the surface of the hypersphere. The distance between clusters different words is greater than the distance across a cluster same word in different font styles. Therefore, by using the centroid of these clusters to build a library of words, input or test words match to the nearest cluster centroid using a minimum distance calculation. This algorithm is capable of correctly recognizing at least 5000 words using 24 various font styles 120,000 individual images.

Subject Categories:

  • Recording and Playback Devices

Distribution Statement:

APPROVED FOR PUBLIC RELEASE