7,505 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
Acoustic Impulse Responses for Wearable Audio Devices
We present an open-access dataset of over 8000 acoustic impulse from 160
microphones spread across the body and affixed to wearable accessories. The
data can be used to evaluate audio capture and array processing systems using
wearable devices such as hearing aids, headphones, eyeglasses, jewelry, and
clothing. We analyze the acoustic transfer functions of different parts of the
body, measure the effects of clothing worn over microphones, compare
measurements from a live human subject to those from a mannequin, and simulate
the noise-reduction performance of several beamformers. The results suggest
that arrays of microphones spread across the body are more effective than those
confined to a single device.Comment: To appear at ICASSP 201
WellâBalanced or too MatchyâMatchy? The Controversy over Matching in DifferenceâinâDifferences
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146629/1/hesr13015.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146629/2/hesr13015_am.pd
Realization of an all-optical zero to Ï cross-phase modulation jump
We report on the experimental demonstration of an all-optical Ï cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or Ï phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor
Spatially Resolved Galaxy Star Formation and its Environmental Dependence I
We use the photometric information contained in individual pixels of 44,964
(0.019<z<0.125 and -23.5<M_r<-20.5) galaxies in the Fourth Data Release (DR4)
of the Sloan Digital Sky Survey to investigate the effects of environment on
galaxy star formation (SF). We use the pixel-z technique, which combines
stellar population synthesis models with photometric redshift template fitting
on the scale of individual pixels in galaxy images. Spectral energy
distributions are constructed, sampling a wide range of properties such as age,
star formation rate (SFR), dust obscuration and metallicity. By summing the
SFRs in the pixels, we demonstrate that the distribution of total galaxy SFR
shifts to lower values as the local density of surrounding galaxies increases,
as found in other studies. The effect is most prominent in the galaxies with
the highest star formation, and we see the break in the SFR-density relation at
a local galaxy density of (Mpc/h). Since our method
allows us to spatially resolve the SF distribution within galaxies, we can
calculate the mean SFR of each galaxy as a function of radius. We find that on
average the mean SFR is dominated by SF in the central regions of galaxies, and
that the trend for suppression of SFR in high density environments is driven by
a reduction in this nuclear SF. We also find that the mean SFR in the outskirts
is largely independent of environmental effects. This trend in the mean SFR is
shared by galaxies which are highly star forming, while those which are weakly
star forming show no statistically significant correlation between their
environment and the mean SFR at any radius.Comment: 37 pages, 11 figures. Referee's comments included and matches version
accepted for publication in the Astrophysical Journal. For high resolution
figures, see http://www.phyast.pitt.edu/~welikala/pixelz/paper1
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