Noise Suppression Method of Distributed Optical Fiber Acoustic Sensing System Based on ALO-VMD Algorithm

Distributed optical fibre acoustic sensing system (DAS) can detect vibration information applied near optical fibres with high sensitivity. The direct detection mode based on amplitude demodulation can realize the monitoring of vibration data with lower sampling frequency and simpler method. However, vibration data is often drowned out by the effects of thermal noise, system fading noise and environmental noise. In order to solve the problem of noise in the system, this study proposes a noise suppression method based on ant-lion optimization algorithm (ALO) and variable mode decomposition (VMD). The algorithm can select the optimal number of decomposition layers and penalty factors adaptively. The experimental results show that the ALO-VMD algorithm has higher decomposition accuracy than VMD algorithm under the condition of low signal-to-noise ratio (SNR), and the signal-to-noise ratio improvement is more obvious compared with the traditional noise reduction algorithm.