Abstract:

Typical echolocation sounds produced by bats and dolphins have a wide bandwidth. This allows the echoes to contain information in the time and frequency domains. Temporal information includes the evolution of the energy in the perceived echo packet. However, if the initial echoes in a packet are weak, they may not exceed the perceptual threshold at a repeatable time, making temporal comparisons difficult. Spectral cues are more robust in that a time delay in an echo packet does not effect the power spectrum. However, because the emitted beam pattern and the reception patterns of the ears are frequency dependent, spectral comparisons are difficult. This paper describes methods for using temporal cues to aid in the spectral comparisons and methods for using spectral cues to aid in the temporal comparisons. The methods are illustrated using experimental results obtained with a biomimetic sonar mounted at the end of a robot arm that is used to recognize a variety of objects. [This research was funded through a grant from the NSF IRI-9504079.]