Denoising Algorithm for φ-OTDR System Based on Adaptive Wavelet Threshold
Phase-sensitive optical time-domain reflectometry(φ-OTDR)offers advantages such as high sensitivity,resistance to electromagnetic interference,and long transmission distance,and is widely used in fields such as rail transit,pipeline monitoring,marine acoustic-signal detection,and perimeter security.However,the performance of φ-OTDR systems is affected by laser,balanced photodetector,erbium-doped fiber amplifier,and environmental noises.Based on existing wavelet denoising algorithms,this study proposes a new adaptive threshold-calculation method and a new continuous low-error wavelet-threshold function using the wavelet coefficients in each layer wavelet transform as parameters for threshold calculation,as well as analyzes the performance of the new wavelet-threshold function.Experimental results show that compared with wavelet soft-and hard-threshold denoising algorithm,the improved adaptive wavelet-threshold denoising algorithm proposed herein offers better denoising effect.
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