Real-Time Interface-Opening Detection for Nickel Starting Sheet Pre-Stripping Based on an Improved YOLO11n

Real-time recognition of the transient interface opening between a nickel starting sheet and its titanium starter plate is required to stop high-frequency tamping at the correct instant. This study proposes Yolov11_tapcheck, a deployment-oriented detector based on YOLO11n, and implements a field real-time detection system for nickel starting sheet pre-stripping. To address small target scale, weak texture, reflective background interference, and motion blur, the model introduces efficient multi-scale attention (EMA) and reconstructs the neck as a BiFPN-inspired bidirectional feature-fusion path. A tapcheck dataset was established from production-line images, and the method was evaluated with image-level accuracy, latency, and field control metrics. Compared with the original YOLO11n, Yolov11_tapcheck improved mAP50 from 95.5% to 98.1% and F1 from 93.7% to 97.5%. The average model-pipeline latency was 7.1 ms; when MQTT delivery, OPCSERVER writing, PLC feedback timestamp comparison, and 1 ms polling were included, the average frame-to-PLC acknowledgement latency was 10.24 ms, with a maximum of 11.58 ms, remaining below the 13.333 ms frame interval in 1000 logged samples. Two field stages further showed that the opening success rate for cycles 3–8 increased from about 60–65% to more than 90%, while opening detection success increased from 90% to 100%. These results indicate that the proposed method can support real-time opening recognition and closed-loop control in nickel starting sheet stripping.