Low-SNR Optoelectronic Signal Reconstruction Based on Zero-Phase Multi-Stage Collaborative Filtering

The Laser Light Screen system faces critical technical challenges in high-speed, long-range target detection: when target passes through the light screen, weak light flux variations lead to significantly degraded signal-to-noise ratios (SNR). Traditional signal processing algorithms fail to effectively suppress phase distortion and boundary effects under extremely low SNR conditions, creating a technical bottleneck that severely constrains system detection performance. To address this problem, this paper proposes a Multi-stage Collaborative Filtering Chain (MCFC) signal processing framework incorporating three key innovations: 1) Design of zero-phase FIR bandpass filtering with forward-backward processing and dynamic phase compensation mechanisms to effectively suppress phase distortion; 2) Implementation of a four-stage cascaded collaborative filtering strategy, combining adaptive sampling and anti-aliasing techniques to significantly enhance signal quality; 3) Development of a multi-scale adaptive transform algorithm based on fourth-order Daubechies wavelets to achieve high-precision signal reconstruction. Experimental results demonstrate that under -20dB conditions, the method achieves a 25dB SNR improvement and boundary artifact suppression while reducing processing time from 0.42 to 0.04 seconds. These results validate the proposed method's effectiveness in high-speed target detection under low SNR conditions.