Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/3114
Título: Emboli detection in middle cerebral artery using continuous wavelet transform
Autor: Gonçalves, Ivo Manuel Belchior
Orientador: Leiria, Isabel
Moura, Maria Margarida Madeira
Palavras-chave: Detecção êmbolo
Processamento sinal
Ultrassom Doppler
Fourier
Wavelet
Signal processing
Doppler ultrasound
Embolus detection
Data de Defesa: 2011
Resumo: Doppler ultrasound is a common non-invasive technique for data acquisition for assistance in clinical analysis and diagnosis. Amongst the clinical applications to blood flow is the detection and characterization of emboli. In this context it was made a comparative study between spectral estimation methods in detection of embolic events in middle cerebral artery blood flow signal. The comparison is made between the Short-Time Fourier Transform and the Continuous Wavelet Transform, whereas the former is the classical and widely discussed method and the latter appears as promising alternative given the known characteristics, such as for non-stationary signal processing. To the signals studied, generated using a simulator, it were added simulated embolic events with known characteristics, like duration, localization and power. The classical method was configured in order to obtain reference results for comparison, whereas the alternative method studied was used with multiple configurations, enabling a richer study on the parameters variation. The analysis to the results obtained for each method was made in terms of false negatives, false positives and sensitivity. The results show that CWT, presented as alternative methods, allows a better embolic events detection rate than STFT, the classical method. All CWT config- urations studied demonstrate better results than STFT. Differences in the results for CWT allow to draw conclusions about the best configuration, among the ones studied, for results optimization, being that the configuration based on Mexican Hat is the one which presents overall better results.
Descrição: Dissertação de mest., Engenharia Eletrónica e Telecomunicações, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011
Peer review: yes
URI: http://hdl.handle.net/10400.1/3114
Designação: Mestrado em Engenharia Eletrónica e Telecomunicações
Aparece nas colecções:UA01-Teses

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