A Real-Time Audio Tele-Presence Device for Remote Acoustic Monitoring

Report No. ARL-CR-502
Authors: Michael A. Vaudrey and Sujayeendar Sachindar
Date/Pages: December 2003; 47 pages
Abstract: This Small Business Innovation Research program sponsored by the U.S. Army Research Laboratory (ARL) addressed the issue of remote monitoring of acoustic environments with the hearing acuity a soldier is accustomed to, without placing the soldier in a potentially hostile acoustic environment. To achieve this goal, Adaptive Technologies, Inc. (ATI) employed a product-oriented design strategy to develop a wired proof-of-concept prototype using commercial-of-the-shelf components. At the end of the Phase I effort, ATI delivered to ARL a fully functional wired binaural hearing device capable of accurately monitoring remote acoustic environments as far as 50 feet from the listener/operator. The remote head and ear system was mounted on a robotic device that permitted pan-and-tilt motion of the remote ears. The orientation of this was commanded by the local user's head location, which was measured by a head-tracking device purchased from Ascension Technologies, Inc. Finally, a customizable audio path equalization process was created to flatten the magnitude response between the remote and local ear canal locations to ensure the highest fidelity and most realistic audio reproduction possible. In addition to the customizable frequency response, ATI provided ARL with a fixed equalization filter that was fit to a small population of users tested at ATI. This generic digital filter was designed to operate at a sampling frequency of 44 kHz. The following is a summary of the technical accomplishments at the end of the Phase I effort: * A remotely deployable binaural hearing system was developed and delivered, which provides the ability to accurately and effectively monitor the remote acoustic environment. * A real-time control system comprising a head tracker and a robotic head was created, which emulates head movement at the remote location, providing the ability to quickly localize any surrounding sound. * Two equalization methods were developed that provide the user with more realistic audio reproduction. The customizable equalization and the fixed generic equalization were both delivered to ARL for testing at the end of the Phase I effort.
Distribution: Approved for public release
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Last Update / Reviewed: December 1, 2003