Method Details
Details for method 'PolyTransform + SegFix + BPR'
Method overview
| name | PolyTransform + SegFix + BPR |
| challenge | instance-level semantic labeling |
| details | Tremendous efforts have been made on instance segmentation but the mask quality is still not satisfactory. The boundaries of predicted instance masks are usually imprecise due to the low spatial resolution of feature maps and the imbalance problem caused by the extremely low proportion of boundary pixels. To address these issues, we propose a conceptually simple yet effective post-processing refinement framework to improve the boundary quality based on the results of any instance segmentation model, termed BPR. Following the idea of looking closer to segment boundaries better, we extract and refine a series of small boundary patches along the predicted instance boundaries. The refinement is accomplished by a boundary patch refinement network at higher resolution. The proposed BPR framework yields significant improvements over the Mask R-CNN baseline on Cityscapes benchmark, especially on the boundary-aware metrics. Moreover, by applying the BPR framework to the PolyTransform + SegFix baseline, we reached 1st place on the Cityscapes leaderboard. |
| publication | Look Closer to Segment Better: Boundary Patch Refinement for Instance Segmentation Chufeng Tang*, Hang Chen*, Xiao Li, Jianmin Li, Zhaoxiang Zhang, Xiaolin Hu CVPR 2021 https://arxiv.org/abs/2104.05239 |
| project page / code | https://github.com/tinyalpha/BPR |
| used Cityscapes data | fine annotations |
| used external data | ImageNet, COCO |
| runtime | n/a |
| subsampling | no |
| submission date | November, 2020 |
| previous submissions |
Average results
| Metric | Value |
|---|---|
| AP | 42.6512 |
| AP50% | 66.5055 |
| AP100m | 57.4983 |
| AP50m | 60.7325 |
Class results
| Class | AP | AP50% | AP100m | AP50m |
|---|---|---|---|---|
| person | 46.0349 | 76.9908 | 63.3646 | 63.4898 |
| rider | 37.1066 | 72.3817 | 51.5779 | 52.2112 |
| car | 62.7507 | 83.7732 | 81.1229 | 83.6874 |
| truck | 41.2719 | 52.6667 | 55.8305 | 64.2081 |
| bus | 52.6533 | 68.5697 | 70.9607 | 77.7261 |
| train | 43.7216 | 63.3475 | 59.933 | 66.5914 |
| motorcycle | 32.6051 | 59.413 | 41.9452 | 42.6975 |
| bicycle | 25.0652 | 54.9011 | 35.2521 | 35.2482 |