Study on Denoising Near Infrared Spectra of Wood Based on Wavelet Transform
WANG Xue-shun1, 2,QI Da-wei2,HUANG An-min3*
1. College of Science, Beijing Forest University, Beijing 100083, China 2. College of Science, Northeast Forest University, Harbin 150040, China 3. Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
Abstract：Near infrared (NIR) spectra of wood samples are often confused by a series of noise, which greatly influences accurate analytical result. In order to improve analytical precision, the authors need to pretreat the spectrum data. Derivative can correct baseline and background effects, increasing the resolution ratio of the spectra. However, it also increases the noise at the same time. The present paper aims at using wavelet transform to eliminate the noise of the near infrared first derivative spectrum of wood with the methods of 9 point smoothing spectrum, 25 point smoothing spectrum, the nonlinear wavelet hard-threshold spectrum, the nonlinear wavelet soft-threshold spectrum, 9 point smoothing+wavelet transform and 25 point smoothing spectrum+wavelet transform. The results show that the wavelet transform has particular advantage on noise elimination of the near infrared spectra while reserving the useful information of spectrum. It can also improve the signal to noise ratio of spectrum, promising the prospect of a wide application in the wood near infrared spectroscopic analysis.
王学顺1, 2,戚大伟2,黄安民3* . 基于小波变换的木材近红外光谱去噪研究[J]. 光谱学与光谱分析, 2009, 29(08): 2059-2062.
WANG Xue-shun1, 2,QI Da-wei2,HUANG An-min3* . Study on Denoising Near Infrared Spectra of Wood Based on Wavelet Transform . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2009, 29(08): 2059-2062.
[1] Schimieck L R, Anthony J M, Carolyn A R. Appita Journal, 2000, 53(4): 318. [2] Kelley S, Hames B, Meglen R. 5th International Biomass Conference of the Americas, 2001. [3] Feldhoff R,Huth-Fehre T, Cammann K. Journal of Near Infrared Sectroscopy, 1998, 6(A): 171. [4] Niemz P, Korner S, Wienhaus O, et al. Holzals Roh-und Werkstoff, 1992, 50(1): 25. [5] HUANG An-min, FEI Ben-hua, JIANG Ze-hui，et al(黄安民，费本华，江泽慧，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2007, 27(9): 1700. [6] YANG Zhong, JIANG Ze-hui, FEI Ben-hua, et al(杨 忠，江泽慧，费本华，等). Scientia Silvae Sinicae(林业科学), 2005, 41(4): 177. [7] SUN Yan-kui(孙延奎). Wavelet Analysis and Application(小波分析及其应用). Beijing: China Machine Press(北京: 机械工业出版社), 2005.
