A novel approach to speech bandwidth expansion based on wavelet transform modulus maxima vector mapping is proposed. By taking advantage of the similarity of the modulus maxima vectors between narrowband and wideband wavelet-analyzed signals a neural network mapping structure can be established to perform bandwidth expansion given only the narrowband version of speech. Since the proposed algorithm works on the time-domain waveforms it offers a flexibility of variable-length frame selection that facilitates low delay and potentially data-dependent speech segment processing to further improve the speech quality. Evaluations based on both objective and subjective measures show that the proposed bandwidth expansion approach results in high-quality synthesized wideband speech with little perceivable distortion from the original wideband speech signals.
Bibliographic reference. Chen, Zhe / Cheng, You-Chi / Yin, Fuliang / Lee, Chin-Hui (2010): "Bandwidth expansion of speech based on wavelet transform modulus maxima vector mapping", In INTERSPEECH-2010, 1101-1104.