Real-Time Conveyor Belt Defect Detection via Edge TPU-Accelerated YOLOv11 on Raspberry Pi 5
Organizations: Department of Electrical Engineering, Faculty of Engineering, Universitas Jenderal Soedirman, Purwokerto 53123, Central Java, Indonesia
Abstract
Conveyor belts are vital arteries in continuous bulk material handling, particularly in heavy process industries such as cement manufacturing. Undetected structural anomalies (longitudinal tears, holes, degraded patch repairs, and impact punctures) cause catastrophic belt snapping, costly downtime, and severe safety hazards. While deep learning offers high accuracy, existing models rely on power-hungry workstation GPUs, hindering practical deployment at remote industrial edge points. In this paper, we propose, implement, and validate an end-to-end, low-power edge AI vision system for real-time conveyor belt defect detection deployed on a Raspberry Pi 5 accelerated by a Google Coral Edge TPU coprocessor. The system leverages an optimized YOLOv11 nano (YOLOv11n) architecture trained on a multi-source industrial corpus exceeding 3,000 augmented samples from an operational cement plant in West Java, open-source datasets, and automated captures. The model undergoes post-training full integer quantization (INT8) compiled for systolic tensor execution. Experimental results demonstrate robust detection capability, achieving precision of 0.742, recall of 0.730, and [email protected] of 0.764 across four defect classes. Deployed on-site in an IP-rated enclosure interfaced with an RTSP PoE industrial camera, the system achieves stable throughput of 30-40 FPS at 320x320 resolution with an end-to-end latency of 70-90 ms. Operational profiling under harsh clinker dust confirms thermal equilibrium at 55 +/- 5 deg C on the host CPU and ~65 deg C on the Edge TPU with zero frame loss. This demonstrates that edge AI bridges the gap between high-accuracy computer vision and cost-effective predictive maintenance in continuous manufacturing.
Figures & tables
| Model Format | Device | 280 px | 320 px | 640 px | Operational Behavior & Observations |
|---|---|---|---|---|---|
| PyTorch ( .pt ) | RPi 5 CPU | 20 FPS | 10 FPS | 3–7 FPS | High CPU load; at 640 px bounding boxes appear with noticeable visual lag. |
| ONNX (CPU) | RPi 5 CPU | — | — | 20 FPS | Evaluated on CPU runtime; steady frame rate but elevated core temperatures. |
| TFLite + Edge TPU | Coral USB | — | 30–40 FPS | 10 FPS | Highest throughput achieved at 320 px; stable real-time Patch Work and Tear detection. |
| Parameter | Measured Value | Operational Context & Stability Status |
|---|---|---|
| Maximum Edge TPU FPS | 30–40 FPS | Measured using RTSP sub-stream at px; smooth defect tracking. |
| Minimum PyTorch FPS | 3–7 FPS | Host CPU at px; inadequate for fast conveyor speeds. |
| ONNX CPU Frame Rate | 20 FPS | General benchmark baseline on host CPU. |
| End-to-End Latency | Cumulative latency from camera sensor exposure, network transport, preprocessing, TPU inference, to display render. | |
| Raspberry Pi 5 Core Temp. | Thermally stable within enclosed metallic panel without active refrigeration. | |
| Google Coral USB Temp. | Consistent thermal equilibrium under continuous 100% TPU utilization. |
Industrial Anomaly Detection
Industrial anomaly detection finds defective products and abnormal equipment behavior from visual, sensor, audio, and other production data.
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