Estimating azimuth and elevation from interaural differences

Modeling of human auditory localization has largely been limited to lateralization, or left-to-right position. This paper describes an attempt to tackle the more complicated problem of position estimation with two degrees of freedom (azimuth and elevation). Differences in interaural intensity and arrival time are extracted from the acoustic signals at the left and right eardrums, and an estimate of position is formed which is optimal for certain classes of source signals. Examples of "spatial likelihood maps" generated by the model are given and the types of errors made by the model are quantified. It is suggested that such a model may work well in conjunction with a spectral cue model like the one suggested by Zakarauskas and Cynader (J. Acoust. Soc. Amer., Vol. 94, 1993, pp. 1323-31).