喇曼散射分布式光纤测温系统实时性的改进

Improvement of real-time performance of Raman scattering distributed optical fiber temperature measurement system

针对双路喇曼散射分布式光纤测温系统测温周期过长的缺点,在保证系统空间分辨率的前提下,提出了硬件数字累加平均技术与小波去噪相结合的信号处理方法。重点讨论了小波去噪中小波基函数的选择、小波分解层数的确定以及阈值量化处理方式的确定三项关键技术。最终采用此种信号处理方法提高了系统信噪比,并将系统测温周期降低至4 s。对比实验结果表明:与硬件数字累加平均相比,小波去噪无论是在改善信噪比还是在减少测温时间方面都具有显著的优势。

A signal processing method was proposed in order to shorten the measure period which is too long in double-channel Raman scattering distributed optical fiber temperature measurement system now.This method combined digital accumulation averaging technology implemented by hardware with wavelet transform decreasing noise technology and improved signal-noise ratio without decreasing measure spatial resolution simultaneously.To achieve best decreasing nosing effect,the mother wavelet function,wavelet decomposition scale and processing method for the quantitative threshold were investigated and the optimized parameter were obtained.Integrated wavelet transform arithmetic were realized in a Raman distributed optical fiber temperature measurement system and the comparing experiment was done with and without wavelet transform decreasing noise technology.The signal-noise ratio of the system was improved obviously and temperature measuring period was decreased to 4 s.The further comparing experiments result indicate that wavelet decreasing noise method is notably superior to hardware digital accumulation averaging technology both in improving signal-noise ratio and decreasing measuring period.