Temporal smoothing

In previous research, we showed that the IACC of natural signals varies a great deal over time [Mason 2002]. Currently it is not known how these variations over time are perceived, and how to model this accurately.

As with most perceptual processes, the perception of variations in the interaural cross-correlation coefficient has been shown to have a limited temporal resolution [Grantham 1982, Boehnke et al. 2002]. However, these studies have focused on the maximum rate of change that is perceivable, rather than the perceived width of time-varying stimuli. In view of this, we conducted research into the effect of a range of temporal variations in the IACC on the perceived width.

The results of this research showed that the perceived effect of temporal variations in the IACC is asymmetric, in that decreases in the IACC appear to be perceived more rapidly than increases in the IACC. The majority of the temporal aspects of the perceived width can be mimicked by the selection of the optimum measurement window length, as described previously. In addition to this, a complex state-dependent filter with a relatively fast rise and a slow decay is required to mimic the subjective results. This has been implemented in the binaural model.