How a reference image reveals PCB defects hidden in plain sight

PCB defect detection fails on tiny flaws buried in complex circuit patterns. RefDiffNet compares a defective board against a defect-free reference image to highlight structural changes, then feeds the enhanced result to any existing detector. On HRIPCB and DeepPCB benchmarks, it delivers 18% mAP improvement across YOLOv8–v26, RT-DETR, and Faster R-CNN while adding only 0.004M parameters—less than 0.25% overhead.