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近红外高光谱技术结合DESCXCeptionNet模型的玉米黄曲霉毒素B1定量分析

Quantitative analysis of aflatoxin B1 in maize using near-infrared hyperspectral combined with DESCXCeptionNet

  • 摘要: 为实现快速、无损检测玉米中黄曲霉毒素B1(aflatoxin B1,AFB1)含量,该研究收集了337组霉变玉米的近红外高光谱数据及其对应的AFB1含量化学值。采用Bootstrap自助重采样方法对原始光谱数据进行数据增强,使用10种预处理方法对原始光谱进行预处理,构建了基于XCeption架构改进的深度增强可分离卷积的极限卷积神经网络(depthwise separable convolution XCeption net,DESCXCeptionNet)模型,用于霉变玉米中的AFB1定量分析。该模型通过层次化扩展深度可分离卷积模块与多尺度特征融合机制,高效提取光谱的深度特征,构建光谱信息与所测化学值之间的内在关联,实现霉变玉米中AFB1含量的定量分析。同时,采用偏最小二乘回归、支持向量机回归、极限学习机、反向传播神经网络、卷积神经网络5种模型进行对比分析。结果表明,在霉变玉米AFB1定量分析中,通过Bootstrap自助重采样数据增强和二阶导数(second derivative,D2)预处理方法结合DESCXCeptionNet模型精度最高,其预测集均方根误差(RMSEP)、预测集决定系数(R2p)和相对分析误差(RPD)值分别为2.942 2 μg/kg、0.979 0和6.899 9,与PLS、SVM、ELM、BP和CNN模型相比,RMSEP值分别由17.779 7、15.365 9、10.323 1、14.432 7、7.939 下降至2.942 2 μg/kg,预测精度分别提升了83.43%、80.85%、71.51%、79.62%和62.94%。综上,近红外高光谱技术结合DESCXCeptionNet模型在霉变玉米AFB1定量分析中具有良好的可行性,能够有效提升模型的预测精度与鲁棒性。该研究为实现霉变玉米中AFB1含量的快速、无损、精确检测提供了一定的数据支持。

     

    Abstract: To achieve rapid and non-destructive detection of aflatoxin B1 (AFB1) content in maize, this study collected near-infrared hyperspectral data and corresponding AFB1 chemical values from 337 groups of moldy maize samples. The Bootstrap resampling method was employed for data augmentation on the original spectral data. Ten preprocessing methods were applied to preprocess the raw spectra, and a depthwise separable convolution XCeption net (DESCXCeptionNet) model, improved based on the XCeption architecture, was constructed for quantitative analysis of AFB1 in moldy maize. This model efficiently extracts deep spectral features through hierarchically expanded depthwise separable convolution modules and a multi-scale feature fusion mechanism, establishing an intrinsic relationship between spectral information and the measured chemical values to achieve quantitative analysis of AFB1 content in moldy maize. Meanwhile, five comparative models were used for analysis: Partial Least Square, Support Vector Regression, Extreme Learning Machine, Back Propagation neural network, and Convolutional Neural Network. The results showed that for quantitative analysis of AFB1 in moldy maize, the combination of Bootstrap data augmentation and second derivative (D2) preprocessing with the DESCXCeptionNet model achieved the highest accuracy. Its root mean square error of prediction (RMSEP), coefficient of determination of prediction (R2p), and relative percent deviation (RPD) were 2.942 2 μg/kg, 0.979 0, and 6.899 9, respectively. Compared with the PLS, SVR, ELM, BP, and CNN models, the RMSEP values decreased from 17.779 7, 15.365 9, 10.323 1, 14.432 7, and 7.939 9 μg/kg to 2.942 2 μg/kg, with prediction accuracy improved by 83.43%, 80.85%, 71.51%, 79.62%, and 62.94%, respectively. In summary, near-infrared hyperspectral technology combined with the DESCXCeptionNet model has good feasibility for quantitative analysis of AFB1 in moldy maize, effectively enhancing the model's prediction accuracy and robustness. This study provides data support for achieving rapid, non-destructive, and accurate detection of AFB1 content in moldy maize. To meet the demand for rapid, non-destructive detection of aflatoxin B1 (AFB1) in maize while overcoming prominent drawbacks of conventional detection approaches including sample damage, procedural complexity, and high costs, this study proposes a novel Depth-enhanced Separable Convolution XCeption Network (DESCXCeptionNet) by integrating near-infrared hyperspectral imaging (NIR-HSI) technology on the basis of an improved XCeption neural network architecture. A controlled artificial mold incubation experiment generated 337 maize seed samples representing diverse AFB1 contamination levels. Hyperspectral signals ranging from 1049.16 nm to 1653.68 nm were acquired for each sample, while fluorescence-based immunochromatography simultaneously quantified the actual AFB1 content, constructing a dataset that correlates spectral signatures and AFB1 concentrations. To address the limitations of insufficient samples and severe spectral spatial heterogeneity, Bootstrap resampling was adopted to augment the original dataset. Comparative experiments with multiplicative stochastic scaling (MS) and conditional generative adversarial network (CGAN) methods further verified its superior data augmentation performance. The augmented data was partitioned into calibration and prediction sets using the Kennard-Stone algorithm. Ten established spectral preprocessing methods, including first derivative (D1), second derivative (D2) preprocessing, Fourier transform (FT), moving average (MA), mean centering (MC), multiplicative scatter correction (MSC), savitzky-golay smoothing (S-G), wavelet transform (WT), standard normal variate (SNV) and smoothing spline (SS), were systematically evaluated for noise reduction and feature enhancement, assessing their comparative impact on model optimization. The DESCXCeptionNet model consisting of four core modules, namely the input flow, middle flow was further constructed to conduct depth expansion and channel expansion of spectral data for quantitatively analysis of AFB1 in moldy maize. Leveraging hierarchically expanded depthwise separable convolution blocks and a multi-scale feature fusion mechanism, this model efficiently extracts deep spectral features and establishes an intrinsic relationship between spectral information and the measured chemical values, thereby realizing accurate regression prediction of AFB1concentrations in moldy corn. Meanwhile, five comparative models were used for analysis: Partial Least Square (PLS), Support Vector Regression (SVR), Extreme Learning Machine (ELM), Back Propagation neural network (BP), and Convolutional Neural Network (CNN). The results indicated that for quantitative analysis of AFB1 in moldy maize, the combination of Bootstrap data augmentation and second derivative (D2) preprocessing maximized feature enhancement and baseline noise suppression. Consequently, the DESCXCeptionNet model achieved optimal detection performance, with the root mean square error of prediction (RMSEP), coefficient of determination of prediction (R2p), and relative percent deviation (RPD) were 2.942 2 μg/kg, 0.979 0, and 6.899 9, respectively, significantly surpassing all benchmark methods. Compared with the PLS, SVR, ELM, BP, and CNN models, the RMSEP values decreased from 17.779 7, 15.365 9, 10.323 1, 14.432 7, and 7.939 9 μg/kg to 2.942 2 μg/kg, with prediction accuracy improved by 83.43%, 80.85%, 71.51%, 79.62%, and 62.94%, respectively. In summary, near-infrared hyperspectral technology combined with the DESCXCeptionNet model has good feasibility for quantitative analysis of AFB1 in moldy maize, effectively enhancing the model's prediction accuracy and robustness. This study provides data support for achieving rapid, non-destructive, and accurate detection of AFB1 content in moldy maize.

     

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