Information transmission with a multifinger tactual display

In this work, the tactual information transmission capabilities of a tactua l display designed to provide stimulation along a continuum from kinestheti c movements to cutaneous vibrations are assessed. The display is capable of delivering arbitrary waveforms to three digits (thumb, index, and middle f inger) within an amplitude range from absolute detection threshold to about 50 dB sensation level and a frequency range from de to above 300 Hz, Stimu lus se,ts were designed at each of three signal durations (125, 250, and 50 0 msec) by combining salient attributes, such as frequency (further divided into low, middle, and high regions), amplitude, direction of motion, and f inger location. Estimated static information transfer (IT) was 6.5 bits at 500 msec, 6.4 bits at 250 msec, and 5.6 bits at 125 msec. Estimates of IT r ate were derived from identification experiments in which the subject's tas k was to identify the middle stimulus in a sequence of three stimuli random ly selected from a given stimulus set. On the basis of the extrapolations f rom these IT measurements to continuous streams, the IT rate was estimated to be about 12 bits/sec, which is roughly the same as that achieved by Tado ma users in tactual speech communication.