1,995 research outputs found
Speech Separation Using Partially Asynchronous Microphone Arrays Without Resampling
We consider the problem of separating speech sources captured by multiple
spatially separated devices, each of which has multiple microphones and samples
its signals at a slightly different rate. Most asynchronous array processing
methods rely on sample rate offset estimation and resampling, but these offsets
can be difficult to estimate if the sources or microphones are moving. We
propose a source separation method that does not require offset estimation or
signal resampling. Instead, we divide the distributed array into several
synchronous subarrays. All arrays are used jointly to estimate the time-varying
signal statistics, and those statistics are used to design separate
time-varying spatial filters in each array. We demonstrate the method for
speech mixtures recorded on both stationary and moving microphone arrays.Comment: To appear at the International Workshop on Acoustic Signal
Enhancement (IWAENC 2018
Optimized Nonuniform FFTs and Their Application to Array Factor Computation
We deal with developing an optimized approach
for implementing nonuniform fast Fourier transform (NUFFT)
algorithms under a general and new perspective for 1-D transformations. The computations of nonequispaced results, nonequispaced data, and Type-3 nonuniform discrete Fourier transforms
are tackled in a unified way. They exploit “uniformly sampled” exponentials to interpolate the “nonuniformly sampled”
ones involved in the nonuniform discrete Fourier transforms
(NUFDTs), so as to enable the use of standard fast Fourier
transforms, and an optimized window. The computational costs
and the memory requirements are analyzed, and their convenient
performance is assessed also by comparing them with other
approaches in the literature. Numerical results demonstrate
that the method is more accurate and does not introduce any
additional computational or memory burden. The computation of
the window functions amounts to that of a Legendre polynomial
expansion, i.e., a simple polynomial evaluation. This is convenient
in terms of computational burden and of the proper arrangement
of the calculations. A case study of electromagnetic interest has
been carried out by applying the developed NUFFTs to the
radiation of linear regular or irregular arrays onto a set of regular or irregular spectral points. Guidelines for multidimensional
extension of the proposed approach are also presented
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