  This paper introduces a novel (HDAG - Harmonic Detection for Auditory Gain)
method for speech intelligibility enhancement in noisy scenarios. In the
proposed scheme, a series of selective Gammachirp filters are adopted to
emphasize the harmonic components of speech reducing the masking effects of
acoustic noises. The fundamental frequency are estimated by the HHT-Amp
technique. Harmonic patterns estimated with low accuracy are detected and
adjusted according the FSFFE low/high pitch separation. The central frequencies
of the filterbank are defined considering the third octave subbands which are
best suited to cover the regions most relevant to intelligibility. Before
signal reconstruction, the gammachirp filtered components are amplified by gain
factors regulated by FSFFE classification. The proposed HDAG solution and three
baseline techniques are examined considering six background noises with four
signal-to-noise ratios. Three objective measures are adopted for the evaluation
of speech intelligibility and quality. Several experiments are conducted to
demonstrate that the proposed scheme achieves better speech intelligibility
improvement when compared to the competing approaches. A perceptual listening
test is further considered and corroborates with the objective results.
