Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the distal interphalangeal (DIP) joints of the index, middle and ring fingers of a receiver, and subsequently dots the right part of the Braille code on the proximal interphalangeal (PIP) joints of the same fingers. Because there is a small number of non-disabled people who are skilled in Finger Braille, deafblind people communicate in this medium only through an interpreter. In our previous study, we have been developing a Finger Braille recognition system using small piezoelectric accelerometers worn by the receiver. To recognize the dotted positions (DIP or PIP joints), we have made a hypothesis that the dotting on the DIP joints causes a hard impact, and the dotting on the PIP joints causes a soft impact, when the receiver’s hand forms a natural longitudinal arch on the desk. The difference of each impact is indicated by its damping amplitude ratio. In this paper, a measurement experiment about the postures of the receiver’s hand was conducted. The postures of the receiver’s hand were as follows: forming the natural longitudinal arch on the desk and fully contacting the desk. As a result, the dotting on the DIP joints of both postures caused the hard impacts; the dotting on the PIP joints caused the soft impact when the receiver’s hand formed the natural longitudinal arch; the dotting on the PIP joints caused the hard impact when the receiver’s hand fully contacted the desk. Therefore, we could verify the hypothesis.
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- Influence of Postures of Hand on Shock Acceleration by Dotting of Finger Braille
- Springer Berlin Heidelberg