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Smart Agriculture ›› 2025, Vol. 7 ›› Issue (4): 119-131.doi: 10.12133/j.smartag.SA202505032

• 专题--农产品品质智能感知与分级 • 上一篇    

基于D-S证据理论的苹果霉心病声振检测方法

刘洁1, 赵康1,2,3, 赵钦君1, 宋烨2,3()   

  1. 1. 济南大学 自动化与电气工程学院,山东 济南 250022,中国
    2. 中华全国供销合作总社济南果品研究所,山东 济南 250220,中国
    3. 国家果蔬及加工产品质量检验检测中心,山东 济南 250220,中国
  • 收稿日期:2025-05-29 出版日期:2025-07-30
  • 基金项目:
    山东省重点研发计划项目(2022TZXD007); 济南大学博士启动基金(XBS2494)
  • 作者简介:

    刘 洁,硕士研究生,研究方向为果蔬无损检测。E-mail:

  • 通信作者:
    宋 烨,博士,研究员,研究方向为果蔬品质智能检测与装备研发。E-mail:

Acoustic-Vibration Detection Method for The Apple Moldy Core Disease Based on D-S Evidence Theory

LIU Jie1, ZHAO Kang1,2,3, ZHAO Qinjun1, SONG Ye2,3()   

  1. 1. School of Automation and Electrical Engineering, University of Jinan, Jinan 250022, China
    2. Jinan Fruit Research Institute, All-China Federation of Supply and Marketing Cooperatives, Jinan 250220, China
    3. China Technology and Research Center for Storage and Processing of Fruit and Vegetables, Jinan 250220, China
  • Received:2025-05-29 Online:2025-07-30
  • Foundation items:The Key R&D Projects in Shandong Province(2022TZXD007); PhD Start-up Fund of University of Jinan(XBS2494)
  • About author:

    LIU Jie, E-mail:

  • Corresponding author:
    SONG Ye, E-mail:

摘要:

【目的/意义】 霉心病是苹果常见的内部病害,具有较强的传染性。在贮藏早期,霉变症状被限制在果核内部,苹果组织处于亚健康状态,但仍具有商品价值,因此对霉核苹果进行早期检测至关重要。 【方法】 本研究利用声振动无损检测系统采集声振动响应信号,采用对称极坐标变换(Symmetrized Dot Pattern, SDP)、格拉姆角场变换(Gramian Angular Field, GAF)和Stockwell变换(Stockwell Transform, ST),其中GAF分为格拉姆求和场(Gramian Angular Summation Field, GASF)和格拉姆差场(Gramian Angular Difference Field, GADF),以此获得声振多域谱的SDP图、GASF图、GADF图和ST图。利用统一局部二值模式法(Uniform Local Binary Pattern, ULBP)和灰度-梯度共生矩阵法(Gray-Level-Gradient Co-occurrence Matrix, GLGCM)分别从多域可视化图像中提取人工特征,同时设计了基于卷积注意力机制模块和Adam优化器改进的ResNet50特征提取器(Adam-IResNet50)从各域可视化图像中自动提取深度特征,构建最优浅层特征训练分类器多元支持向量机(Multiple Support Vector Machine, MSVM)和最优深层特征训练分类器极限学习机(Extreme Learning Machine, ELM)。将两种分类器初步判别结果转化为独立证据体的基本概率分配,然后基于D-S(Dempster-Shafer, D-S)证据理论中的Dempster合成规则和决策判决规则,获得最终的早期霉心苹果决策判决结果,进而构建声振多域谱浅层特征和深层特征决策层融合模型。 【结果和讨论】 构建的Adam-IResNet50-IPSO-ELM-DS模型对熟知产地3类别苹果多分类的Kappa系数和马修斯相关系数(Matthews Correlation Coefficient, MCC)值略低于90%,F1和总体准确率(Overall Accuracy, OA)值分别达到了93.01%和93.22%,对亚健康果的判别准确率达到了87.37%,对病害果误判率为8.33%。表明该模型对3类别苹果的分类不仅能较好兼顾查准能力和查全能力,还保持较高检测精度。 【结论】 提出的基于D-S证据理论的苹果霉心病声振检测方法可有效完成检测任务,为今后早期霉心苹果的在线批量化检测提供技术支撑。

关键词: 声学振动技术, 亚健康苹果, 决策层融合, 无损检测

Abstract:

[Objective] Moldy core disease is a common internal disease of the apple and is highly infectious. In the early storage stage, the mold symptoms are confined to the interior of the core. The apple tissue is in a sub-healthy state and still has commercial value, so early detection of moldy-core apples is critical. [Methods] In this study, a non-destructive acoustic vibration detection system was used to acquire acoustic vibration response signals. Symmetrized dot pattern (SDP), gramian angular field (GAF), and stockwell transform (ST) were applied to obtain multi-domain acoustic vibration spectra, including SDP images, gramian angular summation field (GASF) images, gramian angular difference field (GADF) images, and ST images. These images were uniformly converted to grayscale, transforming the time-domain signals into multi-domain visual spectra to facilitate subsequent feature analysis and recognition. Uniform local binary pattern (ULBP) and gray-level-gradient co-occurrence matrix (GLGCM) methods were used to extract handcrafted features from the multi-domain visualized images. Subsequently, the maximum relevance and minimum redundancy (mRMR) criterion was applied to select the dominant features from each analysis domain that were sensitive to early disease information. Principal component analysis (PCA) was employed to reduce the dimensionality of the multi-domain spectral ULBP texture features. From the statistical features extracted from one-dimensional acoustic-vibration signals in the time and frequency domains, and the GLGCM texture features extracted from two-dimensional images in each domain, 5 to 8 features sensitive to early moldy core detection were selected. From the high-dimensional sensitive ULBP texture features extracted from each domain, 3 to 7 principal components were obtained through dimensionality reduction using principal component analysis. This selection aimed to maximize the relevance between features and class labels while minimizing redundancy among features, thereby identifying the most informative features for early mold core apple detection in each domain. Meanwhile, a ResNet50 feature extractor improved with a convolutional attention mechanism module and the Adam optimizer (Adam-IResNet50) was designed to automatically extract deep features from visualized images in each domain. The optimal shallow features were used to train a multiple support vector machine (MSVM) classifier, while the optimal deep features were used to train an extreme learning machine (ELM) classifier. The Adam-IResNet50 network was employed as a feature extractor. The deep features extracted from the time-domain and frequency-domain GADF images, as well as time-frequency images, resulted in higher sample matching scores (SC) and cluster compactness (CHS) values, along with lower inter-class overlap (DBI) values for the three apple categories. These results clearly indicate that the deep features extracted by the Adam-IResNet50 model from multi-domain images exhibit strong capability in identifying subhealth and moldy core apples. The preliminary outputs of the two classifiers were converted into basic probability assignments for independent evidence bodies. Dempster's combination rule and the associated decision criterion of Dempster-Shafer (D-S) theory were then applied to yield the final decision on early-stage moldy apples. Consequently, a decision-level fusion model was established for both shallow and deep features of the acoustic-vibration multi-domain spectra. [Results and Discussions] The constructed Adam-IResNet50-IPSO-ELM-DS model based on D-S evidence theory achieved a Kappa coefficient and Matthews Correlation Coefficient (MCC) slightly below 90% for multi-class classification of apples from known origins. The F1-Score and Overall Accuracy (OA) reached 93.01% and 93.22%, respectively. The classification accuracy for sub-healthy apples was 87.37%, while the misclassification rate for diseased apples was 8.33%. These results indicate that the model maintains a balanced precision and recall while achieving high detection accuracy for three classes of apples from unknown origins. After decision fusion, the IPSO-MSVM-DS and Adam-IResNet50-IPSO-ELM-DS models demonstrated significant performance improvements. Among them, the Adam-IResNet50-IPSO-ELM-DS model achieved an accuracy of 93.22%, which was significantly higher than that of other methods. This demonstrates that decision-level fusion could effectively enhance the model's discriminative ability and further improve classification performance. [Conclusions] The proposed acoustic vibration detection method for mold core apples, based on Dempster-Shafer evidence theory, provides technical support for future online batch detection of early mold core apples. Early screening of sub-healthy apples is of great significance for quality control during postharvest storage. In future work, the model will be further optimized to develop a rapid acoustic vibration-based prediction method for early detection of mold core, providing technical support for quality control during apple distribution.

Key words: acoustic vibration technology, sub-healthy apple, decision fusion, non-destructive detection

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