DocumentCode :
1488406
Title :
Bandwidth Extension of Telephone Speech Using a Neural Network and a Filter Bank Implementation for Highband Mel Spectrum
Author :
Pulakka, Hannu ; Alku, Paavo
Author_Institution :
Dept. of Signal Process. & Acoust., Aalto Univ., Aalto, Finland
Volume :
19
Issue :
7
fYear :
2011
Firstpage :
2170
Lastpage :
2183
Abstract :
The limited audio bandwidth used in narrowband telephone systems degrades both the quality and the intelligibility of speech. This paper presents a new method for the bandwidth extension of telephone speech. Frequency components are added to the frequency band 4-8 kHz using only the information in the narrowband speech. A neural network is used to estimate the mel spectrum in the extension band in short time frames based on features calculated from the narrowband speech. A wideband excitation signal is generated by spectral folding from the narrowband linear prediction residual and a filter bank is utilized to divide the excitation into four sub-bands that cover the extension band. These sub-bands are weighted such that the estimated mel spectrum is realized. Bandwidth-extended speech is obtained by summing the weighted sub-bands and the original narrowband signal. Listening tests show that this new method improves speech quality compared with narrowband telephone speech and with a previously published bandwidth extension method.
Keywords :
channel bank filters; neural nets; speech processing; telecommunication computing; telephone sets; audio bandwidth; bandwidth extension; filter bank; frequency 4 kHz to 8 kHz; highband mel spectrum; linear prediction residual; narrowband telephone systems; neural network; speech quality; telephone speech; wideband excitation signal; Artificial neural networks; Feature extraction; Frequency domain analysis; Indexes; Narrowband; Speech; Bandwidth extension; listening test; speech enhancement; speech processing;
fLanguage :
English
Journal_Title :
Audio, Speech, and Language Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1558-7916
Type :
jour
DOI :
10.1109/TASL.2011.2118206
Filename :
5742686
Link To Document :
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