6,399 research outputs found
Verification of feature regions for stops and fricatives in natural speech
The presence of acoustic cues and their importance in speech perception have
long remained debatable topics. In spite of several studies that exist in this
eld, very little is known about what exactly humans perceive in speech. This
research takes a novel approach towards understanding speech perception. A
new method, named three-dimensional deep search (3DDS), was developed
to explore the perceptual cues of 16 consonant-vowel (CV) syllables, namely
/pa/, /ta/, /ka/, /ba/, /da/, /ga/, /fa/, /Ta/, /sa/, /Sa/, /va/, /Da/, /za/,
/Za/, from naturally produced speech. A veri cation experiment was then
conducted to further verify the ndings of the 3DDS method. For this pur-
pose, the time-frequency coordinate that de nes each CV was ltered out
using the short-time Fourier transform (STFT), and perceptual tests were
then conducted. A comparison between unmodi ed speech sounds and those
without the acoustic cues was made. In most of the cases, the scores dropped
from 100% to chance levels even at 12 dB SNR. This clearly emphasizes the
importance of features in identifying each CV. The results con rm earlier
ndings that stops are characterized by a short-duration burst preceding the
vowel by 10 cs in the unvoiced case, and appearing almost coincident
with the vowel in the voiced case. As has been previously hypothesized,
we con rmed that the F2 transition plays no signi cant role in consonant
identi cation. 3DDS analysis labels the /sa/ and /za/ perceptual features
as an intense frication noise around 4 kHz, preceding the vowel by 15{20
cs, with the /za/ feature being around 5 cs shorter in duration than that
of /sa/; the /Sa/ and /Za/ events are found to be frication energy near 2
kHz, preceding the vowel by 17{20 cs. /fa/ has a relatively weak burst and
frication energy over a wide-band including 2{6 kHz, while /va/ has a cue
in the 1.5 kHz mid-frequency region preceding the vowel by 7{10 cs. New
information is established regarding /Da/ and /Ta/, especially with regards
to the nature of their signi cant confusions
Deep Learning for Environmentally Robust Speech Recognition: An Overview of Recent Developments
Eliminating the negative effect of non-stationary environmental noise is a
long-standing research topic for automatic speech recognition that stills
remains an important challenge. Data-driven supervised approaches, including
ones based on deep neural networks, have recently emerged as potential
alternatives to traditional unsupervised approaches and with sufficient
training, can alleviate the shortcomings of the unsupervised methods in various
real-life acoustic environments. In this light, we review recently developed,
representative deep learning approaches for tackling non-stationary additive
and convolutional degradation of speech with the aim of providing guidelines
for those involved in the development of environmentally robust speech
recognition systems. We separately discuss single- and multi-channel techniques
developed for the front-end and back-end of speech recognition systems, as well
as joint front-end and back-end training frameworks
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