Calculation Of Human Echolocation Cues By Means Of The Boundary Element Method

Abstract

Some visually impaired people are able to recognize their surroundings by emitting oral sounds and listening to the sound that is reflected at objects and walls. This is known as human echolocation. The present paper reports the calculation of objective auditory cues present in human echolocation by means of the boundary element method using a spherical model of the human head in the presence of a reflecting disc at different positions. The studied frequency range is 100 Hz to 8 kHz. The results show that frequencies above 2 kHz provide information for localization of the object, whereas the lower frequency range might be used for size determination. It is also shown that stationary sound signals in echolocation can provide relevant acoustic cues, so as displacements in the proximity of a reflecting object become frequency-dependent amplitude modulations. Further calculations in a higher frequency range and with a realistic model of a human head could bring more light to the current knowledge in human echolocation