基于改进小波阈值的TDLAS系统一次谐波降噪算法研究
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中图分类号：TD76/67 文献标志码：A
Abstract：The complex underground environment in coal mines，including factors such as light source fluctuation，noise，and environmental interference，canafect the Tunable Diode Laser Absorption Spectroscopy （TDLAS）system.This results ina decreased signal-to-noise ratioof the first-harmonic spectrum signal，which severelycompromises the accuracyand stabilityof gas detection.To address these problems，a first-harmonic denoising algorithm for the TDLASsystem based onan improved wavelet threshold was proposed.First，the optimal waveletbasisand decomposition level weredetermined usinganenumeration algorithm to identify the optimal parameters suitable for the first-harmonic spectrum signal.Then，acontinuously diferentiable threshold functionwas developed to address the issues of abrupt changes in hard thresholdsand detail loss in soft thresholds.Finally，anadaptive thresholdbasedonthelocalvarianceofthe first-harmonicspectrumsignal was designed，enabling the threshold todynamicallyadjustaccording to local signalcharacteristics，therebyachieving precise separation of noiseand effective signals.Simulationresults showed that compared with the traditional wavelet threshold algorithm，the improved wavelet threshold denoisingalgorithm increased the signal-to-noise ratio by 19.03 dB， reduced the mean square error by 98.75% ， and improved the waveform similarity coefficient by 0.083 3，demonstrating superior denoising performance.Methane detection results indicated that the noise energy in the frequency band ofthe denoised signal was significantly reduced，and the useful signal was concentrated in the target frequency band，showing that the improved wavelet threshold denoising algorithm could effectively suppress the noise in the first-harmonic signal.
Key words： tunable diode laser absorption spectroscopy; wavelet transform; improved wavelet threshold; hard threshold function; soft threshold function; first-harmonic spectrum signal; adaptive threshold
0引言
在煤矿生产中，对井下气体的精准监测是保障生产安全的关键环节[。（剩余10624字）
