Lightning magnetic field measuring system in Bogot&amp;#x00E1; &amp;#x2014; Colombia: Signal proccesing method

Escobar, O.; Román, Francisco; Cortes, Camilo A.; Rojas, Herbert E.

doi:10.1109/sipda.2013.6729210

Cited by 4 publications

(2 citation statements)

References 11 publications

(7 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The chosen filter support (bandwidth) ℎ + is the largest support for which the following condition is still satisfied: ( ) ≤ ( ) (13) It was shown in [15,22] that ℎ + is close to the optimal support ℎ * , which results in the optimal trade-off between bias � ℎ ( )� and variance � 2 ℎ_ ( )�. Besides, this solution minimizes the MSE [19].…”

Section: The Ici Algorithm and The Bandwidth Selectionmentioning

confidence: 99%

See 1 more Smart Citation

Local polynomial approximation and intersection of confidence intervals for removing noise of lightning electric field measurements

Rojas

Cortes

Forero-Mejía³

2018

DYNA

View full text Add to dashboard Cite

Lightning electric field (LEF) measurements are aperiodic signals characterized by inherent noise of different sources, i.e., it is not possible to register a noise-free signal. In the last decade, the denoising of LEF measurements has been achieved using some time-frequency representations such as short-time Fourier transform (STFT), wavelet transform (WT) and fractional Fourier transform (FRFT) without definitive results. In this paper, a denoising process applied on LEF measurements using the Local Polynomial Approximation (LPA) is proposed. The window size selection is made by combining the LPA with the intersection of confidence intervals (ICI) algorithm. Furthermore, a cross-validation criterion is used to select the optimal value of the threshold parameter in the LPA-ICI denoising method. It is shown that for different signal-to-noise ratio (SNR) values, the proposed method significantly reduces the noise present in the recorded signals. Finally, a discussion about the processed signatures in terms of some lightning electric field temporal features is performed.Keywords: electric field; intersection of confidence intervals; lightning flash; local polynomial approximation; noise reduction.Aproximación local polinomial e intersección de intervalos de confianza para la remoción de ruido en mediciones de campo eléctrico generado por rayos Resumen Las mediciones de campo eléctrico producido por rayos (LEF) son señales aperiódicas caracterizadas por ruido inherente de diferentes fuentes, es decir, no es posible registrar una señal libre de ruido. En la última década, se ha logrado filtrar mediciones de LEF utilizando algunas representaciones tiempo-frecuencia tales como la transformación de Fourier de corto tiempo (STFT), la transformación wavelet (WT) y la transformación de Fourier fraccionaria (FRFT) sin resultados definitivos. En este trabajo, se propone un proceso de eliminación de ruido aplicado a mediciones de LEF usando la aproximación polinomial local (LPA). La selección del tamaño de la ventana se realiza combinando la LPA con el algoritmo de intersección de intervalos de confianza (ICI). Además, un criterio de validación cruzada se utiliza para seleccionar el valor óptimo del umbral en el método de reducción de ruido LPA-ICI. Se muestra que para diferentes valores de relación señal-a-ruido (SNR), el método propuesto reduce significativamente el ruido presente en las señales registradas. Finalmente, se realiza una discusión sobre las señales procesadas en términos de algunas características temporales del campo eléctrico.Palabras clave: aproximación local polinomial; campo eléctrico; intersección de intervalos de confianza; rayos; reducción de ruido.

show abstract

Section: The Ici Algorithm and The Bandwidth Selectionmentioning

confidence: 99%

“…Recently, noise reduction methods on LEF signals have been extended to the application of the discrete fractional Fourier transform (DFRFT) [13,14]. However, it is not possible to have a desired signal because, by nature, the LEF have a random behavior and the waveforms change with respect to the distance from the lightning strike point.…”

Section: Introductionmentioning

confidence: 99%