MAO Wen-hua1，WANG Yue-qing1，WANG Yi-ming1*，ZHANG Xiao-chao2
1. College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China 2. Chinese Academy of Agricultural Mechanization Sciences, Beijing 100083, China
Abstract：The infestation information on field weeds is the basis of variable spraying herbicides. It was found that the method using the spectral characteristics of plant is superior in real-time respect. The Fourier transform infrared spectrum technique was applied to measure the reflectance of wheat and weeds in the range from 700 to 1 100 nm. The discrimination analysis was done using the SPSS software. Firstly, the source spectrum data were compressed and normalized. Secondly, the characteristic wavelengths were selected by using stepwise method. Thirdly, the discrimination model was set up to use the selected wavelengths as the variables for detecting wheat and weeds. It was shown by the result of discrimination analysis that the correct classification rate of wheat and weeds detection with the selected wavelength points achieved 97%. In addition, the selected wavelength points were marked in the “red edge” of reflectance within some range, and the rate of correct classification increased with the increase in the numbers of the selected wavelength points. According to the selected wavelength points, the proper filters were chosen to perform the multi-spectral images captured and processed with the machine vision system.
[1] Lü Zhao-hui, CHEN Xiao-guang, WU Wen-fu, et al(吕朝辉，陈晓光，吴文福, 等). Natural Science Journal of Jilin University of Technology(吉林工业大学自然科学学报), 2001, 31(3): 90. [2] ZHANG Jian-qin, QU Ping, KUANG Pu-sheng(张健钦, 屈 平, 邝朴生). Journal of Hebei University(Natural Science Edition)(河北大学学报·自然科学版), 2002, 22(4): 410. [3] Brown R B, et al. Remote Sensing for Identification of Weeds in On-Till Corn. Transactions of the ASAE, 1994, 37(1): 297. [4] Vrindts E, et al. Proceedings of the 2<sup>nd</sup> European Conference on Precision Agriculture, 1999，257. [5] Borregaard T, Nielsen H, Norgaard L, et al. Journal of Agricultural Engineering Research, 2000, 75: 4, 389. [6] GAO Xin-ceng, WANG Jin-wu(高信曾, 汪劲武编). Concise Botany Tutorial(植物学简明教程). Beijing: Higher Education Press(北京：高等教育出版社)，1982. [7] ZHANG Qian-qian, LEI Shu-he, WANG Xiu-lin, WANG Lei, YU Ping(张前前，类淑河，王修林，王 磊，于 萍). Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2004，24(10)：1227. [8] Feyaerts F, van Gool L. Pattern Recognition Letters, 2001, v(22): 667.
