Optimization of switchable windows for low-delay spectral analysis-synthesis

We present a novel iterative method for the optimization of switchable pairs of window functions. These windows may be used for block-based spectral analysis-synthesis (AS) in low-delay speech enhancement systems, where the energy compaction of speech sounds is improved by switching the spectral AS windows. Optimization objectives of the approach take the frequency response, quasi perfect reconstruction (PR) of each window pair and quasi-PR during window switching into account. An example of window pairs obtained with the proposed method clearly outperforms a reference design. The improved aliasing and imaging suppression is particularly important for hearing aids where high spectral gains may lead to audible reconstruction artifacts.