【摘要】 红外漫反射光谱技术被广泛地应用于粉末样品的定性、定量测量中。但是由于粉末样品自身的特点,颗粒度、密度、表面粗糙程度等几何参数的影响,使得漫反射光谱数据的信噪比很低、背景干扰很大。因此需要一种有效的方法对漫反射光谱数据进行预处理来提高信噪比,消除背景干扰。文章采用了离散小波变换对红外漫反射光谱进行了预处理,有效地消除了光谱中的高频噪声和低频背景的干扰,并结合iPLS(间隔偏最小二乘回归)方法进行线性回归分析,建立了用于复杂样品体系组分分析的建模方法(DWT-iPLS)。并以烃源岩的红外漫反射光谱为例,将DWT-iPLS应用于数据的预处理及建立数学模型,其结果与未用DWT预处理的方法相比较,准确度有明显的提高,证明了此方法是一种快速有效的定量分析的建模方法。更多还原

【Abstract】 Infrared spectroscopy is useful to monitor the quality of products on-line,or to quality multivariate properties simultaneously.The IR spectrometer satisfies the requirements of users who want to have quantitative product information in real-time because the instrument provides the information promptly and easily.However,Samples that are measured using diffuse reflectance often exhibit significant differences in the spectra due to the non-homogeneous distribution of the particles.In fact,multiple spectral measurements of the same sample can look completely different.In many cases,the scattering can be an overpowering contributor to the spectrum,sometimes accounting for most of the variance in the data.Although the degree of scattering is dependent on the wavelength of the light that is used and the particle size and refractive index of the sample, the scattering is not uniform throughout the spectrum.Typically,this appears as a baseline shift,tilt and sometimes curvature,where the degree of influence is more pronounced at the longer-wavelength end of the spectrum.The diffuse reflection spectrum is unsatisfactory and the calibration may provide unsatisfactory prediction results.So we must use some methods to remove the effects of the scattering for multivariate calibration of IR spectral signals. Discrete wavelet transform(DWT) is a good method to remove the effects of the scattering for multivariate calibration of IR spectral signals.By using DWT on individual signals as a preprocessing method in regression modeling on IR spectra,good compression is achieved with almost no loss of information,the low-frequency varying background and the high-frequency noise be removed simultaneously.In this report,we use the iPLS method to establish the calibration models of hydrocarbon source rocks.iPLS is a new regression method and the authors can get better results by using DTW-iPLS.更多还原