Active Sensing for Three-Dimensional Auditory Localization

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Active sensing for three-dimensional auditory localization The proposed project examines the production, reception and processing of acoustic signals for spatial localization in a dynamic environment. The research described in this proposal utilizes the echolocating bat as a model system for the study of auditory localization, with particular emphasis on the coordinated operation between perception and action for the representation of three-dimensional space. The echolocating bat produces ultrasonic vocalizations and uses information contained in the returning echoes to determine the direction and distance of objects in space. With this acoustic information, the bat builds a three-dimensional auditory representation of the world. The research will combine acoustics, behavior and modeling to specify general principles of spatial information processing and orientation. The big brown bat, Eptesicus fuscus, an insectivorous North American bat that produces frequency modulated (FM) sonar sounds will serve as the subject in three inter-related studies: 1) Detailed measurements of the acoustic information available to the bat for sound localization. This study also examines how cues related to sound source direction and distance are ultimately combined to represent an auditory object's location in three-dimensional space. 2) Behavioral measurements of the bat's active control over the direction and volume of the sonar beam used to gather acoustic information from the environment. This study aims to identify the active processes that contribute to the bat's spatial orientation and tracking by echolocation, which shares important principles with other sensorimotor systems. 3) Perceptual experiments will measure the resolution of the bat's sonar receiver along the distance axis. This study complements the acoustic measures of sonar signal direction and beam width and the pressure transformation of acoustic signals at the two ears to permit modeling of active sensing for auditory localization in three-dimensional space. The interdisciplinary work described in this proposal holds importance to the public sector, contributing to education (cross-disciplinary research and scientific training), technology (teleconferencing and radar/sonar) and society (human factors). Furthermore, the bat's motor control over the information extracted from three-dimensional space presents a special opportunity to examine and develop models of action and perception that bridge work in audition and vision.