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紫外-可见光谱法多参数水质在线监测系统面对复杂水体时,常需要频繁改变探头光程以保持光谱较高的信噪比。然而,适合的光程往往需要大量实验才可确定,难以满足在线监测系统对实时性、精度、灵敏度、稳定性等的实际需求。研究了一种紫外-可见光谱双光程融合优化算法,将同时采集的长短两种光程光谱使用了滑窗法估计它们光谱噪声方差分布,确定光谱强噪声区间;由于长短光程光谱的信号强度不同,使用了遗传算法计算得到双光谱融合的最佳增益匹配倍率;最后,按噪声方差分布使用分段加权方式得到较高信噪比的双光程融合光谱。实验结果表明,利用该法对重庆长寿湖水样、嘉陵江某排污口及邻苯二甲酸氢钾标准溶液三种样本进行测试,其融合光谱在200~250 nm区域的强噪声得到抑制,零值干扰左推至220nm之前,样本的峰值信噪比均有显著提高,证明了算法的有效性和普适性。该算法无需大量实验以获得最佳光程,对于拓宽紫外-可见光谱水质在线监测系统的应用范围具有较为重要的现实意义。
UV-Vis Spectroscopy Multi-parameter Water Quality Online Monitoring System In the face of complex water bodies, it is often necessary to change the optical path of the probe frequently to maintain a high spectral-to-noise ratio. However, the suitable optical path often requires a large number of experiments to determine, which is difficult to meet the actual demand of online monitoring system for real-time, accuracy, sensitivity, stability and so on. A two-path fusion optimization algorithm of UV-visible spectrum was studied. The sliding window method was used to estimate the distribution of the variance of spectral noise of the two optical path spectra collected at the same time, and the strong spectral range was determined. Different intensities, using the genetic algorithm to calculate the best gain matching magnification of the dual-spectrum fusion; Finally, using the method of piecewise weighted distribution of noise variance to obtain a double optical path fusion spectrum of high signal-to-noise ratio. The experimental results show that using this method to test three kinds of samples of Changshou Lake in Chongqing, a sewage outfall in Jialing River and potassium hydrogen phthalate standard solution, the strong noise of the fusion spectrum in the 200-250 nm range is suppressed, and zero-value interference Left push to 220nm before the sample peak signal to noise ratio have significantly increased, proved the effectiveness of the algorithm and universality. The algorithm does not require a large number of experiments to obtain the best optical path, which is of important practical significance for broadening the application range of on-line monitoring system of ultraviolet-visible spectrum water quality.