High-Spatial-Resolution OFDR Distributed Temperature Sensor Based on Step-by-Step and Image Wavelet Denoising Methods

Abstract

A high-spatial-resolution OFDR distributed temperature sensor based on Au-SMF was experimentally demonstrated by using step-by-step and image wavelet denoising methods (IWDM). The measured temperature between 50 and 600 °C could be successfully demodulated by using SM-IWDM at a spatial resolution of 3.2 mm. The temperature sensitivity coefficient of the Au-SMF was 3.18 GHz/°C. The accuracy of the demodulated temperature was approximately 0.24 °C. Such a method has great potential to expand the temperature measurement range, which is very useful for high-temperature applications.

Wavelet Decomposition Layer Selection for the φ-OTDR Signal

“…Wavelet transform (WT) stands as a widely employed technique for denoising, filtering, and compressing signals in distributed fiber optic sensing systems, contributing to the enhancement of various sensing technologies, such as Brillouin optical time-domain analyzer (BOTDA), Brillouin optical time-domain reflectometry (BOTDR), Raman optical time-domain reflectometry (ROTDR), phase-sensitive optical time-domain reflection (φ-OTDR), and optical frequency-domain reflectometer (OFDR), among others technologies [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Its synergy with artificial intelligence methods also helps in time-frequency feature analysis and facilitates feature extraction [15][16][17][18][19][20][21][22].…”