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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Transformada Wavelet na detecÃÃo de patologias da laringe / Wavelet Transform in the detection of pathologies of the larynx

Raphael Torres Santos Carvalho 12 March 2012 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A quantidade de mÃtodos nÃo invasivos de diagnÃstico tem aumentado devido à necessidade de exames simples, rÃpidos e indolores. Por conta do crescimento da tecnologia que fornece os meios necessÃrios para a extraÃÃo e processamento de sinais, novos mÃtodos de anÃlise tÃm sido desenvolvidos para compreender a complexidade dos sinais de voz. Este trabalho de dissertaÃÃo apresenta uma nova ideia para caracterizar os sinais de voz saudÃvel e patolÃgicos baseado em uma ferramenta matemÃtica amplamente conhecida na literatura, a Transformada Wavelet (WT). O conjunto de dados utilizado neste trabalho consiste de 60 amostras de vozes divididas em quatro classes de amostras, uma de indivÃduos saudÃveis e as outras trÃs de pessoas com nÃdulo vocal, edema de Reinke e disfonia neurolÃgica. Todas as amostras foram gravadas usando a vogal sustentada /a/ do PortuguÃs Brasileiro. Os resultados obtidos por todos os classificadores de padrÃes estudados mostram que a abordagem proposta usando WT à uma tÃcnica adequada para discriminaÃÃo entre vozes saudÃvel e patolÃgica, e apresentaram resultados similares ou superiores a da tÃcnica clÃssica quanto à taxa de reconhecimento. / The amount of non-invasive methods of diagnosis has increased due to the need for simple, quick and painless tests. Due to the growth of technology that provides the means for extraction and signal processing, new analytical methods have been developed to help the understanding of analysis of the complexity of the voice signals. This dissertation presents a new idea to characterize signals of healthy and pathological voice based on one mathematical tools widely known in the literature, Wavelet Transform (WT). The speech data were used in this work consists of 60 voice samples divided into four classes of samples: one from healthy individuals and three from people with vocal fold nodules, Reinkeâs edema and neurological dysphonia. All the samples were recorded using the vowel /a/ in Brazilian Portuguese. The obtained results by all the pattern classifiers studied indicate that the proposed approach using WT is a suitable technique to discriminate between healthy and pathological voices, since they perform similarly to or even better than classical technique, concerning recognition rates.

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