Resumo

TORRES, M.E et al. Evaluation of noise reduction techniques in speech signals. Cienc. docencia tecnol. [online]. 2010, n.40, pp.115-132. ISSN 1851-1716.

The present work evaluates the intelligibility and the quality of speech signals after being processed using a group of noise reduction techniques. The intelligibility is measured in percentage of correctly recognized words in a subjective test, and the most frequent phonetic sustitutions are discussed in terms of confusion matrices. The quality of the obtained signals is evaluated also in an objective way starting from a group of measures selected ad-hoc. In this work the evaluation is presented for some of the most commonly employed classic techniques, such as Spectral Subtraction, Wiener and Ephraim-Malah filtering. The results of the preliminary evaluation of more recent techniques are also shown, as the ones based in the Wavelet transform. The relative performance of each considered algorithm is presented and discussed.

Palavras-chave : Bioengineering; Auditory prostheses; Noise reduction algorythms; Wavelet transform; Intelligibility.

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