Application of Morlet Wavelet in the Extraction of Brillouin Scattering Signal Envelope

作者:Wang Xin*; Huang Cha xiang; Zhou Li
来源:5th International Symposium on Photoelectronic Detection and Imaging (ISPDI) - Fiber Optic Sensors and Optical Coherence Tomography, 2013-06-25 to 2013-06-27.
DOI:10.1117/12.2032483

摘要

The Brillouin scattering light signal is a wideband signal containing a lot of phase noises and amplitude noises. And the envelope of the Brillouin scattering signal will include some characteristics due to the influences of temperature and strain change on the sensing fiber. In order to obtain the useful temperature and strain change information, the amplitude demodulation of the noise signal should be conducted, and at the same time, it is necessary to effectively suppress the signal noise. In this paper, Morlet wavelet has been used to do the envelope detection since it has band-pass filtering function and signal demodulation function provided by the orthogonal characteristic between real part and imaginary part. Moreover, the Morlet wavelet function has the characteristic of time-frequency analysis, and it can analyze envelope of the signal and extract characteristic of the signal in the whole frequency range by changing the scale factor and translation factor. Meanwhile, it can also suppress the signal noise effectively. The simulation model has been built to verify the validity of envelope demodulation principle by Morlet wavelet algorithm. Theory analysis and experiment show the algorithm is reasonable and efficient.