Robustness Techniques for Feature Extraction - Berlin Chen
Robustness Techniques for Feature Extraction - Berlin Chen
Robustness Techniques for Feature Extraction - Berlin Chen
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Spectral Subtraction (SS)<br />
• Modification: Nonlinear Spectral Subtraction (NSS)<br />
Pˆ<br />
P<br />
S<br />
⎧PX<br />
( ω ) − PN<br />
( ω ),<br />
if PX<br />
( ω ) ≥ PN<br />
( ω )<br />
( ω ) = ⎨<br />
⎩PN<br />
( ω ),<br />
otherwise<br />
( ω ) and P ( ω ): smoothed noisy and noise spectrum<br />
X<br />
N<br />
or<br />
Pˆ<br />
P<br />
φ<br />
⎧P<br />
( ) ( ) ( ) ( ) ( )<br />
X<br />
ω − φ ω , if PX<br />
ω > φ ω + β ⋅ PN<br />
ω<br />
( )<br />
S<br />
ω = ⎨<br />
⎩β<br />
⋅ P ( ω )<br />
N<br />
, otherwise<br />
( ω ) and P ( ω )<br />
X<br />
N<br />
: smoothed noisy and noise<br />
( ω ):<br />
a non - linear function according to SNR<br />
spectrum<br />
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