Tese de Doutorado
Tese de Doutorado
Tese de Doutorado
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Abstract of Thesis presented to UFSC<br />
as a partial fulfillment of the requirements for the <strong>de</strong>gree of<br />
Doctor in Electrical Engineering<br />
AQUISIÇÃO E PROCESSAMENTO DE SONS CREPITANTES<br />
PARA AUXÍLIO AO DIAGNÓSTICO DE ENFERMIDADES<br />
PULMONARES<br />
Daniel Ferreira da Ponte<br />
Junho/2011<br />
This paper discusses the <strong>de</strong>velopment and implementation of<br />
a system of acquisition of lung sounds of low-cost techniques to<br />
investigate the acquisition and processing of crackling sounds that are<br />
present in patients with cystic fibrosis, pneumonia and congestive heart<br />
failure (CHF). The goal is to capture sounds that carry more diagnostic<br />
information and analyze them to better <strong>de</strong>fine diagnostic criteria<br />
proposed in the literature. Therefore aims to contribute to the<br />
achievement of quantitative parameters that may assist the diagnosis and<br />
monitoring of clinical status of patients. The results showed that using<br />
high-pass filter and allow a<strong>de</strong>quate returns the record sounds with<br />
higher maximum frequency. It also discussed the effect of attenuation<br />
caused by the sound path between the lungs and chest area<br />
compromising the analysis of crackling, because it alters the<br />
morphological and spectral those signals. To recover the signal<br />
subjected to the effect of channel equalization techniques have been<br />
applied FLSI (Fir Least Square Inverse) and EVA (Eigenvector<br />
Approach) and raising the maximum frequency and morphology of<br />
recovering the signal. This work also shows that the use of techniques<br />
and DPWD (Pseudo Discrete Wigner-Ville Distribution) and MGM<br />
(Modified Geometric Method) appropriate to non-stationary signal, the<br />
crackling allows the objective <strong>de</strong>tection of its maximum frequency in<br />
different diseases, enabling the differentiation of patients with fibrosis<br />
and pneumonia among patients with fibrosis and congestive heart<br />
failure. With the technique it was possible to estimate the maximum<br />
frequency higher in the studied illnesses reported in the literature. The<br />
variation of relative volume and respiratory rate measured in these rates<br />
did not change the estimate of the maximum frequency was statistically<br />
significantly so.<br />
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