Aural Discrimination of Targets by Human Subjects Using Broadband Sonar Pulses
Final rept. for period ending FY 1981
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
Pagination or Media Count:
Sonar echo discrimination experiments were conducted with human subjects, using targets employed in a dolphin echo-recognition study. Digital recordings of the target echoes were obtained using a dolphin-like echolocation signal with a peak-frequency of 122 kHz, and were played back to the subject at 150 of the original sample rate. Targets included hollow cylinders of aluminum, bronze, steel and glass having diameters of 3.81 and 7.62 cm, and a solid 7.62- cm aluminum cylinder. All targets were 17.78 cm in length. Echo amplitudes were adjusted so that stimulus intensity was not a cue. The subjects discriminated between echoes from 1 solid and hollow, and 2 small and large aluminum cylinders with correct responses of 98 and 92, respectively, after one session per task. Correct responses for the aluminum-bronze and the aluminum-steel discriminations were 98 and 95, respectively. Correct responses for the aluminum-glass discrimination varied between 72 and 98. Differences in time- separation-pitch associated with correlated echo highlights and differences in echo duration were the predominant discrimination cues.
- Acoustic Detection and Detectors
- Human Factors Engineering and Man Machine Systems