Processamento de sinais e reconhecimento de padrões de resposta de sensores de gases através da geometria fractal. / Signal processing and pattern recognition of gas sensors response by fractal geometry.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The aim of the present work was to propose methods for signal possessing and pattern, recognition from the signals response of gas sensors using models and techniques from the fractal geometry. The data studied and analyzed were obtained from two kinds of sensors. The first sensor was the tin oxide device, which detection principle is based on the resistivity changes of the tin oxide film and it provides noisy signals as response to the gas interaction. The second sensor was a metal-oxide-semiconductor (MOS) device, which has as the working principle the photocurrent generation. This sensor provides two-dimensional images signals. A method using a fractional Brownian motion was proposed to analyze the noise signal from the tin oxide device. The fuel gases discrimination employing this model was 100% successful. Two different methods were proposed to analyze the signal response from the MOS device. The first method was based on the fractal image compression technique and the second one was based on the analysis and determination of the multiscale fractal dimension. Both proposed methods have shown to be efficient tools for signature determination as the pattern recognition of all gases that were used in the experiment. The results obtained in the present work open new frontiers and perspectives inside the paradigms of the signal processing and pattern recognition by using the fractal theory.

ASSUNTO(S)

movimento browniano fracionário pattern recognition partial iterated function system fractal geometry geometria fractal reconhecimento de padrões sistemas de funções iteradas parciais fractional brownian motion sensores sensors

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