Hyperspectral Estimation of Soluble Solids Content in Winter Jujube Based on LSTM-TE Model
LIU Ao-ran1, 2, MENG Xi2, LIU Zhi-guo2, SONG Yu-fei2*, ZHAO Xue-man2, ZHI Dan-ning2
1. School of College of Computer and Cyber Security, Hebei Normal University, Hebei Provincial Key Laboratory of Network & Information Security, Hebei Provincial Engineering Research Center for Supply Chain Big Data Analytics & Data Security, Shijiazhuang 050024, China
2. School of Future Information Technology, Shijiazhuang University, Hebei Key Laboratory of WoT Blockchain Integration, Shijiazhuang 050035, China
Abstract:Winter jujube is favored by consumers for its rich nutritional content, sweet taste, and excellent flavor. With the increasing demands of consumers for fruit quality, Soluble Solids Content (SSC) has become a key factor in fruit quality evaluation, serving as an important indicator for measuring fruit ripeness and taste quality. Therefore, efficient and non-destructive prediction of winter jujube SSC has significant practical value and importance. This paper proposes an LSTM-TE model, which integrates Long Short-Term Memory (LSTM) networks with a Transformer Encoder, aiming to achieve rapid and non-destructive prediction of winter jujube SSC. By collecting hyperspectral data from 900 winter jujube samples and determining their SSC values, multiple spectral data preprocessing methods (including Multivariate Scatter Correction (MSC), Vector Normalization (VN), Savitzky-Golay (SG) filtering, first derivative (D1), and second derivative (D2)) were applied to process the data. The effects of 10 preprocessing combinations were compared through five models: PLSR, SVR, VGG16, ResNet18, and LSTM, to determine the optimal preprocessing scheme, MSC-SG-D1. Based on this preprocessing method, a multi-model comparison system was further constructed, including PLSR, SVR, VGG16, ResNet18, LSTM, and LSTM-TE, and their performance was analyzed on the test set. Experimental results showed that the LSTM-TE model achieved a coefficient of determination of 0.959 8 and a root mean square error (RMSE) of 1.269 0 on the test set, an improvement of 17.4% compared to the traditional machine learning modelPLSR (R2p=0.817 3) and 10.9% compared to the single LSTM model (R2p=0.865 2). This model effectively explored the nonlinear feature relationships in hyperspectral data by capturing temporal features through LSTM and leveraging the global dependency modeling advantages of the Transformer encoder. This study provides a new technical solution for the online detection and grading of winter jujube quality, offering important reference value for applying hyperspectral technology in precision agriculture.
Key words:Soluble Solids Content (SSC);Hyperspectral;Deep learning;LSTM-TE model
刘傲然,孟 惜,刘智国,宋宇斐,赵雪曼,智丹宁. 基于LSTM-TE模型的冬枣可溶性固形物含量高光谱估测[J]. 光谱学与光谱分析, 2025, 45(08): 2326-2334.
LIU Ao-ran, MENG Xi, LIU Zhi-guo, SONG Yu-fei, ZHAO Xue-man, ZHI Dan-ning. Hyperspectral Estimation of Soluble Solids Content in Winter Jujube Based on LSTM-TE Model. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(08): 2326-2334.
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