| _ | infrequent | _ |
|---|---|---|
| Unsupervised learning approach for abnormal event detection in surveillance video by revealing | infrequent | patterns |
| _ | infrequently | _ |
|---|---|---|
| Active learning for designing detectors for | infrequently | occurring objects in wide-area satellite imagery |
| Visual-Attention-Based Background Modeling for Detecting | infrequently | Moving Objects |