Patent ID: RE40993

Claim:
A typing recognition apparatus for touch typing on surfaces with limited tactile feedback that compensates for finger and hand drift during typing and discourages any integrated spelling model from choosing dictionary words over unusual but carefully typed strings, the apparatus comprising: a typing surface means that displays symbols indicating the locations of touchable keys; touch sensor means that provides the surface coordinates of each touch by a typist attempting to strike said key symbols on said surface; hypothesis tree generator means that extends existing key hypothesis sequences with hypotheses for keys in the neighborhood of each new touch; pattern geometry evaluation means that computes geometry match metrics for the hypothesized key sequences by comparing separation vectors between the successive touch locations with separation vectors between the successively hypothesized key locations as well as by measuring the zero-order key/touch alignment error; decoding means that finds the hypothesized key sequence with the best cumulative match metric; and, transmission means for communicating the symbols and commands represented by the best hypothesized key sequence to host computer applications.