chapter
5 Pages

Pen-based Ubiquitous Computing System for visually Impaired Person

We propose the pen-based ubiquitous computing system for visually impaired person. In general the software keyboard is used for the character input at PDA. However, a visually impaired person cannot use the software keyboard directly because s/he cannot select the character key-button on the screen monitor. As a solution to these problems, we adopt an on-line character input system using handwritten character recognition technology instead of a keyboard for visually impaired person. Our character input system is installed on pen-based PDA system with two buttons that are able to control for all command operations. In order to investigate the performance of the proposed system, we have addressed the issue of using the PDA to use in sending, receiv ing and managing electronic mail by wireless LAN. However, since many characters having a small number of strokes (such as Hiragana and Katakana) were contained in the mail documents, the character recognition accuracy was significantly decreased in our recognition system. So w^e also developed an improvement method of the recognition accuracy by combining the voting method with our original recognition method and two conventional methods. In addition, a phrase unit order recognition method based on a tri-gram probable language model was added to the system. By applying these additional improvement methods, the recognition accuracy was improved to 97.7% from 66.2%, and we confirmed the required performance for utilization.