Effect of domain selection for compact representation of spatial variation of Head-Related Transfer Function in all directions based on Spatial Principal Components Analysis

In this article, compact representation of spatial variation of Head-Related Transfer Function (HRTF) or its corresponding inverse Fourier transform, namely Head-Related Impulse Response (HRIR) based on Principal Components Analysis (PCA), which is called the Spatial Principal Component Analysis (SPCA), is investigated, focusing on effect of domain selection. The SPCA was carried out for a database of HRTFs in all directions by selecting the domain as one of the HRIRs, the complex HRTFs, the frequency amplitudes of HRTFs, and log-amplitudes of HRTFs. In the latter two cases the minimum phase approximation was incorporated. Comparison of the accuracy in both time and frequency domains showed that the most compact representation is obtained by using the frequency amplitudes of HRTFs when the minimum phase approximation is acceptable, and the complex HRTFs bring about the most compact representation when the minimum phase approximation is not acceptable.