Wearable tactile sensor system for reading braille

This paper is a study on the development of a wearable sensor system for reading Braille. The study is intended to develop a compact tactile sensor system which uses a PVDF (Polyvinylidene Fluoride) film as the sensory receptor. The sensor is mounted onto a fingertip and moved over Braille manually to obtain the sensor output. Since the unsteady movements yield variations in the waveforms, a robust recognition system is required. The recognition system consists of three components as follows. First, the signal inputted to the system is divided into individual signals regardless of the variations in the waveforms. Next, those signals are transformed into effective feature vectors in order to suppress the variations. Finally, those vectors are classified and the results are obtained. In the process, minimum-distance classifiers and neural classifiers are used. For the investigation of experimental verification, test signals are inputted to the recognition system and the performance of the system is evaluated. The obtained results show that the wearable sensor with the recognition system is effective to recognize Braille.