FCOS: Fully Convolutional One-Stage Object Detection

ICCV 2019  ·  Zhi Tian, Chunhua Shen, Hao Chen, Tong He ·

We propose a fully convolutional one-stage object detector (FCOS) to solve object detection in a per-pixel prediction fashion, analogue to semantic segmentation. Almost all state-of-the-art object detectors such as RetinaNet, SSD, YOLOv3, and Faster R-CNN rely on pre-defined anchor boxes. In contrast, our proposed detector FCOS is anchor box free, as well as proposal free. By eliminating the predefined set of anchor boxes, FCOS completely avoids the complicated computation related to anchor boxes such as calculating overlapping during training. More importantly, we also avoid all hyper-parameters related to anchor boxes, which are often very sensitive to the final detection performance. With the only post-processing non-maximum suppression (NMS), FCOS with ResNeXt-64x4d-101 achieves 44.7% in AP with single-model and single-scale testing, surpassing previous one-stage detectors with the advantage of being much simpler. For the first time, we demonstrate a much simpler and flexible detection framework achieving improved detection accuracy. We hope that the proposed FCOS framework can serve as a simple and strong alternative for many other instance-level tasks. Code is available at:Code is available at: https://tinyurl.com/FCOSv1

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Task Dataset Model Metric Name Metric Value Global Rank Result Benchmark
Object Detection COCO minival FCOS (ResNet-50-FPN + improvements) box AP 38.6 # 179
AP50 57.4 # 96
AP75 41.4 # 85
APS 22.3 # 69
APM 42.5 # 66
APL 49.8 # 76
Object Detection COCO-O FCOS (ResNet-50) Average mAP 16.7 # 38
Effective Robustness 0.25 # 32
Object Detection COCO test-dev FCOS (HRNet-W32-5l) box mAP 42.0 # 174
AP50 60.4 # 128
AP75 45.3 # 119
APS 25.4 # 91
APM 45.0 # 110
APL 51.0 # 132
Hardware Burden None # 1
Operations per network pass None # 1
Object Detection COCO test-dev FCOS (ResNeXt-101-64x4d-FPN) box mAP 43.2 # 156
AP50 62.8 # 106
AP75 46.6 # 105
APS 26.5 # 83
APM 46.2 # 99
APL 53.3 # 115
Hardware Burden None # 1
Operations per network pass None # 1
Object Detection COCO test-dev FCOS (ResNeXt-32x8d-101-FPN) box mAP 42.7 # 166
AP50 62.2 # 113
AP75 46.1 # 115
APS 26.0 # 87
APM 45.6 # 102
APL 52.6 # 120
Hardware Burden None # 1
Operations per network pass None # 1
Object Detection COCO test-dev FCOS (ResNeXt-64x4d-101-FPN 4 + improvements) box mAP 44.7 # 137
AP50 64.1 # 90
AP75 48.4 # 89
APS 27.6 # 71
APM 47.5 # 82
APL 55.6 # 96
Hardware Burden None # 1
Operations per network pass None # 1
2D Object Detection SARDet-100K FCOS box mAP 49.8 # 7
Pedestrian Detection TJU-Ped-campus FCOS R (miss rate) 31.89 # 4
RS (miss rate) 69.04 # 2
HO (miss rate) 81.28 # 5
R+HO (miss rate) 39.38 # 4
ALL (miss rate) 41.62 # 4
Pedestrian Detection TJU-Ped-traffic FCOS R (miss rate) 24.35 # 6
RS (miss rate) 37.40 # 3
HO (miss rate) 63.73 # 6
R+HO (miss rate) 28.86 # 5
ALL (miss rate) 40.02 # 4

Methods