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基于高光谱成像技术的山楂含水量快速无损分析

白瑞斌1(), 王慧1, 王宏鹏2, 洪家顺3, 周骏辉1, 杨健1,3()   

  1. 1. 中国中医科学院 中药资源中心/道地药材品质保障与资源持续利用全国重点实验室,北京 100700,中国
    2. 浙江科技学院 生物与化学工程学院,浙江 杭州 310023,中国
    3. 江西省道地药材质量评价研究中心,江西赣江 330000,中国
  • 收稿日期:2025-05-29 出版日期:2025-08-14
  • 基金项目:
    国家重点研发计划项目(2024YFC3506800); 中国中医科学院科技创新工程项目(CI2023E002); 中央本级重大增减支项目(2060302); 国家中医药管理局高水平中医药重点学科建设项目(ZYYZDXK-2023244); 财政部和农业农村部国家现代农业产业技术体系项目(CARS-21); 中国中医科学院基本科研业务费优秀青年科技人才培养专项(ZZ16-YQ-040); 中国中医科学院中药资源中心自主选题研究项目(ZZXT202312)
  • 作者简介:

    白瑞斌,博士,助理研究员,研究方向为中药资源品质评价。E-mail:

  • 通信作者:
    杨 健,博士,副研究员,研究方向为中药资源品质评价。E-mail:

Rapid and Non-Destructive Analysis of Hawthorn Moisture Content Based on Hyperspectral Imaging Technology

BAI Ruibin1(), WANG Hui1, WANG Hongpeng2, HONG Jiashun3, ZHOU Junhui1, YANG Jian1,3()   

  1. 1. State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
    2. School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China
    3. Evaluation and Research Center of Daodi Herbs of Jiangxi Province, Nanchang 330000, China
  • Received:2025-05-29 Online:2025-08-14
  • Foundation items:National Key R&D Program of China(2024YFC3506800); Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences(CI2023E002); Major increase and decrease in expenditure at the central level(2060302); National Administration of Traditional Chinese Medicine High-level Key Discipline Construction Project of Traditional Chinese Medicine(ZYYZDXK-2023244); China Agricultural Research System of MOF and MARA(CARS-21); Excellent Young Scientists Cultivation Program of China Academy of Chinese Medical Sciences(ZZ16-YQ-040); Independent Research Project of National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences(ZZXT202312)
  • About author:

    BAI Ruibin, E-mail:

  • Corresponding author:
    YANG Jian, E-mail:

摘要:

【目的/意义】 为实现山楂水分含量的快速无损检测,本研究探索了一种基于高光谱成像技术结合机器学习算法的检测方法。 【方法】 首先,收集458个来自不同产区不同品种的新鲜山楂样品,分别采集每个样品在可见-近红外波段(Visible to Near Infrared, VNIR)和短波红外(Short-Wave Infrared, SWIR)波段的高光谱数据,利用阈值分割算法确定每个山楂的感兴趣区域(Region of Interest, ROI),提取果实ROI的平均反射光谱作为原始数据。随后,采用卷积平滑、乘法散射校正、标准正态变换、一阶导数和二阶导数五种预处理方法,对原始光谱数据进行优化。在此基础上,结合偏最小二乘回归、支持向量回归(Support Vector Regression, SVR)、随机森林与多层感知机等机器学习方法,系统评估不同摆放方式(果柄朝侧面、朝上、朝下及三者融合)和光谱范围(VNIR、SWIR、VNIR+SWIR)对模型预测性能的影响。最后,采用连续投影算法、竞争自适应重加权采样算法、变量迭代空间收缩方法,以及离散小波变换-逐步回归(Discrete Wavelet Transform-Stepwise Regression, DWT-SR)四种方法对全波段数据进行降维处理,进一步减少数据冗余,提高模型效率。 【结果和讨论】 果柄朝下的摆放方式、SWIR波段范围(940~2 500 nm)及一阶导数预处理组合下,SVR模型表现最优,测试集的绝对系数(Coefficient of Determination, R2p )为0.860 5、平均绝对误差(Mean Absolute Error, MAE p )= 0.711 1、均方根误差(Root Mean Square Error, RMSE p )=0.914 2、相对分析误差(Ratio of Performance to Deviation, RPD)=2.677 6。在性能最优分析条件下,DWT-SR方法基于小波基函数“db6”在分解层级为1时,提取出17个关键特征波段,所建模型在降低数据维度的同时可以保持高水平预测性能(R2p =0.857 1、MAE p = 0.669 2、RMSE p =0.925 2、RPD=2.645 7)。 【结论】 本研究证明了高光谱成像结合机器学习方法在山楂水分无损检测中的可行性,为果品水分在线监测及智能分选提供了理论依据与技术支撑。

关键词: 山楂, 高光谱成像, 小波变换, 支持向量机, 含水量

Abstract:

[Objective] This study aimed to develop a rapid and non-destructive method for determining the moisture content of hawthorn fruits using hyperspectral imaging (HSI) integrated with machine learning algorithms. By evaluating the effects of different fruit orientations and spectral ranges, the research provides theoretical insights and technical support for real-time moisture monitoring and intelligent fruit sorting. [Methods] A total of 458 fresh hawthorn samples, representing various regions and cultivars, were collected to ensure diversity and robustness. Hyperspectral images were acquired in two spectral ranges: visible–near-infrared (VNIR, 400–1 000 nm) and short-wave infrared (SWIR, 940-2 500 nm). A threshold segmentation algorithm was used to extract the region of interest (ROI) from each image, and the average reflectance spectrum of the ROI served as the raw input data. To enhance spectral quality and reduce noise, five preprocessing techniques were applied: Savitzky-Golay (SG) smoothing, multiplicative scatter correction (MSC), standard normal variate (SNV), first derivative (FD), and second derivative (SD). Four regression algorithms were then employed to build predictive models: partial least squares regression (PLSR), support vector regression (SVR), random forest (RF), and multilayer perceptron (MLP). The models were evaluated under varying fruit orientations (stem-side facing downward, upward, sideways, and a combined set of all three) and spectral ranges (VNIR, SWIR, and VNIR+SWIR). To further reduce the dimensionality of the hyperspectral data and minimize redundancy, four feature selection methods were applied: successive projections algorithm (SPA), competitive adaptive reweighted sampling (CARS), variable iterative space shrinkage approach (VISSA), and discrete wavelet transform combined with stepwise regression (DWT-SR). The DWT-SR method utilized the Daubechies 6 (db6) wavelet basis function at a decomposition level of 1. [Results and Discussions] Both fruit orientation and spectral range had a significant impact on model performance. The optimal prediction results were achieved when the stem-side of the fruit was facing downward, using the SWIR range (940–2 500 nm) and FD preprocessing. Under these conditions, the SVR model exhibited the highest predictive accuracy, with a coefficient of determination (R2) of 0.860 5, mean absolute error (MAE) of 0.711 1, root mean square error (RMSE) of 0.914 2, and residual prediction deviation (RPD) of 2.677 6. Further feature reduction using the DWT-SR method resulted in the selection of 17 key wavelengths. Despite the reduced input size, the SVR model based on these features maintained strong predictive capability, achieving R2 = 0.857 1, MAE = 0.669 2, RMSE = 0.925 2, and RPD = 2.645 7. These findings confirm that the DWT-SR method effectively balances dimensionality reduction with model performance. The results demonstrate that the SWIR range contains more moisture-relevant spectral information than the VNIR range, and that first derivative preprocessing significantly improves the correlation between spectral features and moisture content. The SVR model proved particularly well-suited for handling nonlinear relationships in small datasets. Additionally, the DWT-SR method efficiently reduced data dimensionality while preserving key information, making it highly applicable for real-time industrial use. [Conclusions] In conclusion, hyperspectral imaging combined with appropriate preprocessing, feature selection, and machine learning techniques offers a promising and accurate approach for non-destructive moisture determination in hawthorn fruits. This method provides a valuable reference for quality control, moisture monitoring, and automated fruit sorting in the agricultural and food processing industries.

Key words: hawthorn, hyperspectral imaging, wavelet transform, support vector machine, moisture content

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