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Proceedings Paper

Near-infrared spectroscopic measurement system of the constituent concentration based on acousto-optic tunable filter
Author(s): Qingbo Li; Chengzhi Jiang; Kexin Xu
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Paper Abstract

The near-infrared spectroscopic measurement system of constituent concentration based on acousto-optic tunable filter (AOTF) is investigated in this paper. However, the diffracted beam is often mixed with zero order beam in AOTF optical system. In order to obtain high wavelength resolution and spectral signal-to noise ratio (SNR), the solutions to improve the purity and efficiency of the diffracted light are proposed. The orthogonal polarizing method and the combine modulation method of optics and electronics are discussed. The results show that both methods can effectively eliminate the inference of zero order light. Especially, the combined modulation method not only can increase wavelength resolution and spectral signal-to-noise ration but also simplify the optical system structure and reduce costs. The application concerning the determination of the milk principal constituents verifies the validity of this measuring instrument and analytical method. The results show that the speed is 30 seconds/sample. The milk principal constituents concentrations are determined with root mean square error of prediction (RMSEP): 0.1~0.2 g/dL. Correlation coefficients between prediction values and reference values are higher than 0.9. Moreover, the results are reliable with coefficient of variation (Cv) of repeatability below 0.02. Obviously, the individual component’s prediction accuracy and repeatability can meet practical measurement requirement.

Paper Details

Date Published: 20 September 2002
PDF: 8 pages
Proc. SPIE 4927, Optical Design and Testing, (20 September 2002); doi: 10.1117/12.471697
Show Author Affiliations
Qingbo Li, Tianjin Univ. (China)
Chengzhi Jiang, Tianjin Univ. (China)
Kexin Xu, Tianjin Univ. (China)


Published in SPIE Proceedings Vol. 4927:
Optical Design and Testing
Zhicheng Weng; Jose M. Sasian; Yongtian Wang, Editor(s)

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