  This paper presents a speech enhancement method, where an adaptive threshold
is statistically determined based on Gaussian modeling of Teager energy (TE)
operated perceptual wavelet packet (PWP) coefficients of noisy speech. In order
to obtain an enhanced speech, the threshold thus derived is applied upon the
PWP coefficients by employing a Gaussian pdf dependent custom thresholding
function, which is designed based on a combination of modified hard and
semisoft thresholding functions. The effectiveness of the proposed method is
evaluated for car and multi-talker babble noise corrupted speech signals
through performing extensive simulations using the NOIZEUS database. The
proposed method is found to outperform some of the state-of-the-art speech
enhancement methods not only at at high but also at low levels of SNRs in the
sense of standard objective measures and subjective evaluations including
formal listening tests.
