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研究生: 柯蘇菲
Chladek, Sophie-Marie
論文名稱: Comparative Evaluation of Sensor- and Image-Based Learning Pipelines for Photovoltaic Shading Root Cause Classification
Comparative Evaluation of Sensor- and Image-Based Learning Pipelines for Photovoltaic Shading Root Cause Classification
指導教授: 謝昱銘
Hsieh, Yu-Ming
共同指導: 鄭芳田
Cheng, Fan-Tien
學位類別: 碩士
Master
系所名稱: 智慧半導體及永續製造學院 - 半導體製程學位學程
Program on Semiconductor Manufacturing Technology
論文出版年: 2026
畢業學年度: 114
語文別: 英文
論文頁數: 119
外文關鍵詞: Photovoltaic Monitoring, Root-Cause Classification, Time-Series Classification, Computer Vision, Image Segmentation, Multimodal Fault Diagnosis, Smart PV Maintenance
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  • Photovoltaic systems are increasingly deployed as key components of sustainable energy infrastructure, creating a growing demand for deployable intelligent monitoring solutions capable of detecting performance degradation and identifying the underlying external root causes of power loss. Conventional electrical monitoring is effective in indicating abnormal behaviour; however, its ability to distinguish between visually different shading scenarios remains limited due to the indirect nature of temporal sensor signals. To address this challenge, this study proposes and evaluates a deployment-oriented multimodal deep learning framework for photovoltaic shading root-cause classification by integrating electrical sensor-based time-series learning with image-based visual diagnostics. The developed methodology includes: (1) a multivariate sensor classification pipeline using LSTM, TCN, and Transformer architectures, (2) an image-based computer vision pipeline using YOLOv8 object detection, RT-DETR transformer detection, and YOLOv8 segmentation for spatial shading analysis, and (3) a hybrid deployment strategy combining continuous sensor screening with targeted image-based fault verification. Experimental validation was performed on a custom laboratory dataset consisting of synchronized photovoltaic sensor measurements and annotated image samples under leaf, dirt, and geometric shadow conditions. The results demonstrate that sensor-based time-series models can identify abnormal PV behaviour to a moderate extent but remain limited for fine-grained root-cause classification, while image-based models provide direct spatial information and stronger task-specific performance. Based on these findings, the study provides a practical deployment reference for future intelligent photovoltaic maintenance systems.

    SUMMARY 3 1 Introduction 10 1.1 Research Background 10 1.2 Research Motivation 10 1.3 Research Objective 12 1.4 Research Process 14 1.5 Thesis Organization 16 2 Literature Review and Core Technologies 18 2.1 Literature Review 18 2.1.1 The Importance of Solar PV Energy 18 2.1.2 Failure Categories 18 2.1.3 Shading and Soiling in PV Systems 18 2.1.3.1 Dirt and Soiling 18 2.1.3.2 Shading Theory and Classification 19 2.1.4 The Importance of PV Monitoring 20 2.1.5 Methodologies for PV Fault Detection 20 2.1.5.1 Traditional and Sensor-Based Pipelines 20 2.1.5.2 Image-Based Pipelines and Feature Extraction 21 2.2 Core Technologies 22 2.2.1 Data Augmentation via SMOTE-Tomek and VAE-Based Methods 22 2.2.1.1 Variational Autoencoder (VAE) 23 2.2.1.2 SMOTE and SMOTE-Tomek 23 2.2.2 LSTM 24 2.2.3 TCN 26 2.2.4 Transformer 27 2.2.5 Computer Vision 29 2.2.5.1 Object Detection - Yolo 30 2.2.5.1.1 Backbone and Feature Extraction 30 2.2.5.1.2 Anchor-Free and Decoupled Head Mechanism 31 2.2.5.1.3 Loss Formulation and Detection Metrics 31 2.2.5.2 Transformer Detection - RT-DETR 32 2.2.5.3 Segmentation YoloSeg 34 3 Evaluation Framework and Methodology 37 3.1 Evaluation Framework 37 3.2 Workflow Design and Pipeline Structure 38 3.3 Evaluation Methodology 39 3.3.1 Evaluation Metrics 40 3.4 Framework Alignment with Research Questions 41 4 Experimental Set up and Data Acquisition 42 4.1 Functional Requirements Analysis 42 4.2 Laboratory Configuration 43 4.3 Sensor Data Acquisition 44 4.4 Experimental Test Matrix 46 4.5 Data Acquisition Methodology 48 4.6 Image Data Acquisition 49 4.7 Annotation Process 49 5 Sensor-Based Pipeline 52 5.1 Scope and Structure 52 5.2 Feature Correlation Analysis 53 5.3 Data Preprocessing 55 5.4 Data Mode Implementation 58 5.4.1 Standard Date Mode (Real Data only) 58 5.4.1.1 Dataset Construction 58 5.4.1.2 Feature Scaling and Integrity Preservation 59 5.4.1.3 Handling of Class Imbalance 60 5.4.2 VAE-SMOTE Augmented Data Mode 60 5.4.2.1 VAE-Based Latent Representation Learning 61 5.4.2.2 SMOTE in Latent Space 61 5.4.2.3 Decoding of Synthetic Samples 62 5.4.2.4 Dataset Augmentation and Storage 62 5.4.3 Summary 63 5.5 Model Architectures 63 5.5.1 Model Implementation 64 5.5.2 LSTM Architecture Implementation 64 5.5.2.1 LSTM - Role in This Work 65 5.5.3 Transformer Architecture Implementation 66 5.5.3.1 Transformer - Role in this Work 66 5.5.4 TCN Architecture Implementation 67 5.5.4.1 TCN - Role in this work 68 5.6 Training Integration 68 5.7 Methodological Summary 69 6 Image-Based Pipeline 70 6.1 Scope and Structure 70 6.2 Data Preprocessing 70 6.3 Model Implementation 72 6.3.1 Dataset Preparation and Integration 72 6.3.2 Unified Training Workflow 73 6.3.3 Implementation of Image-Based Model Architectures 73 6.3.4 YOLO Object Detection 73 6.3.5 RT-DETR (Transformer-Based Detection) 74 6.3.6 YOLO Segmentation (YOLO-seg) 74 6.4 Model Evaluation 75 6.5 Summary 75 7 Results and Evaluation 76 7.1 Objective 76 7.2 Sensor-based Pipeline Results 76 7.2.1 LSTM 77 7.2.1.1 LSTM Standard Mode 77 7.2.1.2 LSTM VAE-SMOTE 77 7.2.2 Temporal Convolutional Networks (TCN) 78 7.2.2.1 TCN Standard Mode 78 7.2.2.2 TCN VAE-SMOTE 78 7.2.3 Transformer 79 7.2.3.1 Transformer Standard Mode 79 7.2.3.2 Transformer VAE-SMOTE 79 7.3 Image-based Pipeline Results 79 7.3.1 YOLO 80 7.3.1.1 Overall Model Performance 80 7.3.1.2 Precision-Recall Characteristics 81 7.3.1.3 Confusion Matrix 83 7.3.1.4 Training Behavior and Model Convergence 85 7.3.1.5 Qualitative Evaluation 86 7.3.2 RT-DETR 87 7.3.2.1 Overall Model Performance 88 7.3.2.2 Precision-Recall Characteristics 89 7.3.2.3 Confusion Matrix 91 7.3.2.4 Training Behavior and Model Convergence 92 7.3.2.5 Qualitative Evaluation 94 7.3.3 YOLO-Seg 95 7.3.3.1 Overall Model Performance 95 7.3.3.2 Precision-Recall Characteristics 97 7.3.3.3 Confusion Matrix 99 7.3.3.4 Training Behavior and Model Convergence 100 7.3.3.5 Qualitative Evaluation 102 7.4 Performance Evaluation and Comparative Analysis 103 7.4.1 Sensor-Based Pipeline 103 7.4.2 Image-Based Pipeline 105 7.5 Cross-Pipeline Comparison 108 7.5.1 Limits of Sensor-Based Pipeline 108 7.5.2 Advantage of Image-Based Pipeline 108 7.6 Practical Framework and Deployment Strategy 109 7.6.1 Stage 1: Continuous Electrical Filtering 110 7.6.2 Stage 2: On-Demand Visual Diagnosis 110 8 Conclusion 113 8.1 Conclusion 113 8.2 Future Work 115 REFERENCES 117

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