提出一种新的有效的FTIR光谱气体浓度反演的方法。该方法将区间划分的思想用于红外光谱波长优化筛选,即将红外光谱在给定波长范围内划分为若干个子区间,在每个子区间中利用遗传算法(genetic algorithm,GA)优化后的极限学习机(extreme learning machine,ELM)建立浓度预测模型,根据每个子区间测试集均方根误差RMSE和相关系数R2的大小评价模型的泛化性能,筛选出最优子区间组合建立预测模型。通过含干扰组分(CO2,N2O)的CO气体的FTIR光谱对提出的算法进行了验证,在波段为2 140~2 220cm-1范围内利用区间法筛选出的最优组合作为变量,应用GA-ELM建立的浓度反演模型,其决定系数R2为0.987 4,均方根误差RMSE为154.996 3,建模时间仅为0.8s,表明该算法(Interval-GA-ELM,iGELM)的应用不仅缩短了建模时间,而且在干扰组分存在的情况下,依然可以准确筛选出特征波长,从而提高了模型稳定性和预测精度,为大气污染气体遥测分析提供了行之有效的方法。
This paper proposed a novel effective quantitative analysis method for FTIR spectroscopy of polluted gases ,which se-lect the best wavenumbers based on the idea of interval dividing .Meanwhile ,genetic algorithm was adopted to optimize the con-nect weights and thresholds of the input layer and the hidden layer of extreme learning machine (ELM ) because of its global search ability .Firstly ,the whole spectrum region was divided into several subintervals ;Secondly ,the quantitative analysis mod-el was established in each subinterval by using optimized GA-ELM ;Thirdly ,the best combination of subintervals was selected according to the generalized performance of each subinterval model by computing the parameters root mean square error (RMSE) and determined coefficients r .In this paper ,the mixture of CO ,CO2 and N2 O gases were selected as the research object and the whole spectrum range was from 2 140 to 2 220 cm -1 .The experiment results showed that the RMSE of model established with