Handprinted Data Entry with a Touch-Sensitive Numeric Keypad

A new method for handprinted data entry is proposed for those user tasks where only few characters have to be entered. The basic idea is to use a numeric keypad as writing surface for one finger. For this purpose the keys are equipped with touch sensors, and display elements are fitted to the keys and the intermediate spaces. By means of the arrangement of the keys in the keypad the writing surface has a structure of rows and columns which motivates the user to produce characters with a standard format and uniform line elements. In order to allow characters to be sloppily written to some extent, the method of dynamic programming was applied for a nonlinear adaptation of pattern and prototype vectors. A first series of experiments showed that error rates of the subjects (e.g. omissions, confusions) and of the pattern recognition system (errors, rejections) are very low.