Handwriting recognition device, method and alphabet, with strokes grouped into stroke sub-structures

A method of providing an alphabet of sub-strokes for handwriting recognition comprising:

• collecting pen input from a plurality of writers of a selected language;
• determining the maximum number of segments that an alphanumeric symbol may have;
• identifying segmentation points in the pen input that are at significant bends in the pen input;
• segmenting the pen input at the segmentation points into strokes and stroke sub-structures;
• parameterizing the strokes and stroke substructures to provide stroke parameters;
• establishing an alphabet size;
• deriving an alphabet of a first set of strokes and at least a second set of stoke sub-structures, by clustering the strokes and stroke sub-structures and averaging stroke parameters across samples in a cluster, where the total number of elements in the sets is equal to the alphabet size;
• and
• introducing during a preprocessing procedure any required artificial strokes to correspond to pen motion to enable cursive forms of writing to be handled the same way as print forms of writing.

A device for handwriting recognition comprising:

• a memory having instructions and data stored therein that, when executed cause a digital processor to comprise:
• a pen stroke information input;
• a segmenter and grouper coupled to the input, having a stroke and stroke sub-structure output;
• a processor to preprocess the strokes to enable cursive forms of handwriting and print forms of handwriting to be handled in the same manner the process further for determining the maximum number of segments that an alphanumeric symbol may have;
• a template store having stored therein templates quantized according to a predefined alphabet of strokes and stroke substructures;
• and
• a quantizer operative on the segmenter and grouper to compute distance and angle measurements between parameters of strokes and stroke sub-structures of the stroke and stroke sub-structure output and parameters of strokes and stroke sub-structures of templates in the template store and thereby to select at least one template.

A method of recognizing handwriting comprising the steps of:

• receiving a pen input;
• segmenting the input into parameterized straight-line strokes at significant bends in the pen input;
• preprocessing the strokes to enable cursive and print character entry to be handled in the same manner;
• determining the maximum number of segments that an alphanumeric symbol may have;
• grouping the straight-line strokes into input stroke sub-structures comprising combinations of straight-line strokes;
• and
• computing distance and angle measurements between parameters of the input stroke sub-structures and corresponding parameters of members of a predefined set of strokes and primitive stroke sub-structures.