Localization of Head-Mounted Vibrotactile Transducers

Report No. ARL-TR-6322
Authors: Mary S. Binseel and Joel T. Kalb
Date/Pages: February 2013; 36 pages
Abstract: The Global Positioning System (GPS) and communications systems transmit information through visual and auditory channels, diverting attentional resources from other tasks and degrading situation awareness. The tactile channel is proposed as an alternative sensory modality in order to reduce visual and auditory load. Most systems currently useduse trunk- or extremity-mounted tactors. Consequently, little is known about the psychophysical parameters associated with head-mounted vibrotactile (VT) displays. This study investigated the ability of humans to determine the location of an activated VT transducer (tactor). Seven tactors were placed on the head corresponding to electroencephalogram (EEG) locations for EEG recordings. The selected sites were F3, Cz, Pz, O2, T3, T4, and F8. Tactors were activated at vibration frequencies of 32, 45, and 63.5 Hz (1/2 octave center frequencies). The stimulus consisted of three cycles of 62.5 ms of tactor excitation followed by 187.5 ms of no signal. The stimulus level was about 10 dB above average tactor detection thresholds. Frequency and location were randomized, and 12 trials per frequency/location combination were presented. Participants responded by indicating at which of the seven locations they perceived the stimulus to be occurring. Results showed that participants correctly identified the activated tactor in 84% of the trials.
Distribution: Approved for public release
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Last Update / Reviewed: February 1, 2013