一种改进的小波除噪方法用于含噪ICP-AES光谱的处理  

Application of a Modified Method of Wavelet Noise Removing to Noisy ICP-AES Spectra

作　　者：马晓国[1] 张展霞[2] 

机构地区：[1]广东工业大学分析测试中心,广东广州510090 [2]中山大学化学系,广东广州510275

出　　处：《光谱学与光谱分析》2003年第3期552-555,共4页Spectroscopy and Spectral Analysis

基　　金：教育部博士学科点专项基金资助项目

摘　　要：提出了一种改进的小波除噪方法。它基于噪声具有频率较高和幅度较小的特点 ,先排除信号中频率较高的成分 ,再丢弃余下的系数较小的成分。对模拟的含噪电感耦合等离子体原子发射光谱 (ICP AES)的处理结果表明 ,该法能克服小波平滑和小波去噪的一些缺陷 ,可去除更多噪声 ,而信号强度不受影响。同时 ,基线变得平坦 ,有利于峰高的定量计算。用该法处理实测ICP AES光谱 ,效果满意。A new method for noise removal from signal by the wavelet transform. was developed. Compared with analytical signal, noise has higher frequency and smaller amplitude. By the new wavelet filtering method, the high frequency components were first removed I and then the small ones in the remaining transformed vectors were discarded. The proposed approach was evaluated by the processing of simulated and experimental noisy ICP-AES spectra. Different amounts of noise were added to a Gaussian peak to obtain a series of noisy ICP spectra. The simulated noisy spectra with R (signal to noise ratic) = 6 and N (data number) = 51, and with R = 6 and N = 17 were used to illustrate the feasibility of the proposed method. The performances of noise removal by the wavelet smoothing, the wavelet denoising and the proposed technique were compared. It was found that using the new approach, the relative errors of peak height would be no more than 5% for spectra with normal sampling points and R greater than or equal to 2. Moreover, the baseline could be easily defined, which was helpful to the accurate measurement of peak height. Experimental spectra of Al and V at low concentrations were processed by the proposed method. Intense noises were efficiently removed and the spectra became smoother without underestimating the analytical signal. The distortion of V 303.310 nm line was substantially rectified. The linear correlation coefficients between the peak heights in the reconstructed spectra and the concentrations were found to be 0.9953 for Al and 0. 9836 for V, respectively.

关 键 词：小波变换 噪声 除噪方法 电感耦合等离子体原子发射光谱分析 ICP-AES光谱 信号分解 

分 类 号：TN911.4[电子电信—通信与信息系统] O657.31[电子电信—信息与通信工程]