Brief Introduction

• Indicate the "essential difference" between anchor-based and anchor-free detectors
• Propose an "adaptive training sample selection" to automatically select positive and negative training samples
• Demonstrate tiling multiple anchors per location is useless
• Achieve SOTA performance on MS COCO without overhead

Recent vision models

anchor-based & anchor-free

• Mainly two methods for vision processing

Anchor-based

• Double-stage: Faster R-CNN
• Single-stage: Single Shot Detection (SSD)

Anchor-free

• Keypoint-based method: CornerNet
• Center-based method: YOLO

Difference Analysis between two

• RetinaNet (anchor-based) vs. FCOS (anchor-free)
• Attention points
• Dataset: MS COCO (80 object classes)
• RetinaNet (#A=1) → one square anchor box per location

Inconsistency removal