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UBC Theses and Dissertations

An experimental system for recognizing typewritten characters Fletcher, Thomas Ralph


An optical character recognition system was developed using the Lexiphone, a direct-translation reading machine for the blind, interfaced to a digital computer. The system was designed to read alphanumeric typewritten characters. In the development stages one serifed type-style was used exclusively. Three additional different, but serifed, type-styles were also used. Classification was performed by a method referred to as "component deletion". This method extends a nearest neighbours classification scheme enabling feature vectors differing in length by one two-bit segment to be compared by making their dimensionality the same. The method includes the classification of equal length vectors. The component deletion technique provided similar results to exact matching yet required significantly less training. Using carbon ribbon print, recognition was better than 92% for the four type-styles combined. The use of cloth ribbon for the type-style used in the development lowered recognition by a few percent.

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