Research on Denoising Method of Agricultural Product Terahertz Spectroscopy Based on Adaptive Signal Decomposition
WU Jing-zhu1, LIU Yu-hao1, YANG Yi1*, XIE Chuan-luan2, LÜ Zhong-ming1, LI Yi-can1
1. Beijing Key Laboratory of Big Data Technology for Food Safety, Beijing Technology and Business University, Beijing 100048, China
2. Beijing Research Institute of Automation for Machinery Industry Co., Ltd., Beijing 100120, China
Abstract:To address the issues of peak overlap caused by complex matrices in agricultural product terahertz (THz) spectral signals and the dynamic, nonlinear interference induced by environmental and system noise, this study explores the feasibility of adaptive-signal-decomposition-based denoising methods to improve THz spectral quality. THz time-domain spectroscopy (THz-TDS) combined with an attenuated total reflection (ATR) accessory was used to collect THz absorbance spectra from 48 peanut samples. Taking the quantitative prediction model of peanut moisture content based on THz-ATR as an example, wavelet transform (WT), empirical mode decomposition (EMD), local mean decomposition (LMD), and its improved methods—segmented local mean decomposition (SLMD) and piecewise mirror extension local mean decomposition (PME-LMD)—were employed for spectral denoising. The applicability of different denoising methods was evaluated using a support vector regression (SVR) model. Experimental results show that the peanut moisture content prediction model constructed after PME-LMD denoising achieved the best performance, with a root mean square error (RMSE), coefficient of determination (R2), and mean absolute percentage error (MAPE) of 0.010, 0.912, and 0.040, respectively. Compared with traditional methods, PME-LMD significantly improved spectral quality and model prediction performance. The PME-LMD denoising strategy proposed in this study effectively suppresses non-uniform noise interference in THz spectral signals, providing an efficient and accurate preprocessing method for THz spectral analysis of agricultural products. This research provides theoretical support and technical guidance for the application of THz technology for detecting agricultural product quality.
Key words:Terahertz spectroscopy; Denoising method; Agricultural products; Support vector regression; Piecewise mirror extension local mean decomposition
基金资助: Supported by the National Key R&D Program of China (2023YFD2101001), National Natural Science Foundation of China (32202144,61807001)
通讯作者:
杨 一
E-mail: yangyi@btbu.edu.cn
作者简介: WU Jing-zhu, female, (1979—), Professor, Beijing Key Laboratory of Big Data Technology for Food Safety, Beijing Technology and Business University e-mail: pubwu@163.com
引用本文:
吴静珠,刘宇昊,杨 一,谢传銮,吕钟鸣,李沂灿. 基于自适应信号分解的农产品太赫兹光谱去噪方法研究[J]. 光谱学与光谱分析, 2025, 45(12): 3575-3584.
WU Jing-zhu, LIU Yu-hao, YANG Yi, XIE Chuan-luan, LÜ Zhong-ming, LI Yi-can. Research on Denoising Method of Agricultural Product Terahertz Spectroscopy Based on Adaptive Signal Decomposition. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(12): 3575-3584.
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