Abstract Characterizing Braille on the smart touch screen mobile terminal is a practically significant but difficult task. In order to enable the visually impaired obtain the information by touching the Braille on the smart touch screen mobile terminal, three common Chinese Braille encoding methods based on mobile terminal with variable friction tactile were proposed, which were general Braille encoding method,tone embedding encoding method and four-lines two-columns encoding method.According to the principle that the ultrasonic vibration generated by piezoelectric sensor could produce variable friction tactile on the object surface, the Chinese Braille tactile code was realized on the smart mobile terminal. Through two systematic experiments on 12 blind users, the usability of encoding method was evaluated from the aspects of reading efficiency, reading accuracy and user satisfaction. Firstly, the usability of three encoding methods was evaluated (experiment 1). Based on the results of experiment 1, the four-lines two-columns encoding method was selected to compare with the vibration motor tactile feedback encoding method based on right-sliding touch reading mode for usability. The results of experiment 1 showed that the average reading efficiency of three encoding methods was 8.82, 4.91 and 4.12 s/Chinese character, and the average reading accuracy was 98.6%, 96.8%, and 98.6%, respectively. Among them, the score of four-lines two-columns encoding method was the highest. The results of experiment 2 showed that,compared with the vibration motor tactile feedback encoding method based on right-sliding touch reading mode, the four-lines two-columns encoding method had higher reading efficiency, reading accuracy and user satisfaction. In conclusion, using the four-lines two-columns encoding method is able to encode and read the common Chinese Braille on the mobile terminal, which can provide a new way for the visually impaired to read Braille on smart mobile terminal.
ZHANG Fan, CHU Shao-wei, JI Na-ye. Chinese Braille encoding design for mobile terminal with variable-friction tactile. Chinese Journal of Engineering Design, 2020, 27(2): 154-161.
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