Weather Adaptive Autonomous Driving
Organizations: Dept. of Computing and Software Engineering, Florida Gulf Coast University, Fort Myers, FL, USA
Abstract
Camera object detectors lose recall in rain, fog, snow and sand, and the confidence threshold at which a detector is deployed decides how many objects it misses and how many false alarms it raises. We study how a frozen detector should make this decision in adverse weather. We first reproduce SeqCRC, a conformal object detector whose first step calibrates the confidence threshold by conformal risk control (CRC), and use that step, calibrated separately in each weather condition, as our baseline. With YOLOv8x it keeps the held-out miss fraction within a 20% budget in every DAWN weather bin, where a single global threshold fails in fog, but the false alarms it needs are an output rather than a choice: from 1.6 to 117 per image across DAWN and BDD100K conditions. We then propose a calibrated trade-off dial. One setting, , the number of false alarms accepted to avoid one missed object, selects the expected-cost-optimal decision rule: either one score threshold, or a per-detection rule that keeps a box when its calibrated probability of being a real object, estimated by gradient-boosted trees from the detector's own per-box outputs, is at least . F-score preferences map onto the same dial, and CRC applied to itself is planned to restore a per-condition miss guarantee. The dial is fitted once on BDD100K train and graded only on BDD100K val and DAWN.
Figures & tables
| Paper | Method | Sensor / input | Dataset | Key result | Limitation |
| Weather-robust detection and benchmarks | |||||
| Sakaridis [ 1 ] , IJCV’18 | Physics-based synthetic fog; fog fine-tuning | RGB camera | Foggy Cityscapes; Foggy Driving (101 real) | Car AP 30.5 35.3 on 33 finely annotated real images | Homogeneous daytime fog; tiny real test set |
| Hassaballah [ 8 ] , T-ITS’21 | Visibility enhancement + multi-scale CNN + GM-PHD tracker; introduces DAWN | RGB camera | DAWN (fog, rain, snow, sand), KITTI, COCO | Reported to outperform 21 compared vehicle detectors | Small real-image set (1,027 released images); no official splits |
| Chen [ 2 ] , CVPR’18 | Adversarial image + instance alignment (DA Faster R-CNN) | RGB camera | Cityscapes Foggy Cityscapes; SIM10k; KITTI | Foggy [email protected] 18.8 27.6 | Retrains per shift; synthetic fog; AP/mAP only, no operating point |
| Li [ 3 ] , WACV’23 | Hardness-weighted GRL + rainy-domain triplet loss (DA-Detect) | RGB camera | Cityscapes Foggy Cityscapes; KITTI | Foggy [email protected] 23.41 42.34 (oracle 45.6) | Synthetic fog only; 3.5-pt hyperparameter swing; no operating point |
| Liu [ 4 ] , AAAI’22 | CNN-predicted differentiable filters before YOLOv3 | RGB camera | VOC-Foggy/Dark; RTTS; ExDark | RTTS mAP 28.82 37.08 (30.80 for same-data YOLOv3) | Retrains detector; mAP only |
| Baseline (SeqCRC step 1 per weather bin) | Ours (trade-off dial) | |
|---|---|---|
| Detector | YOLOv8x, frozen COCO weights, 1280 px, score floor 0.001 | unchanged |
| Decision rule | one score threshold per weather bin, | per detection, ; simple option: one threshold |
| Trade-off | fixed miss budget ; false alarms unpriced | explicit input (or ); planned as a floor via CRC over |
| Run-time inputs | score and the weather bin | score, box context and the detector’s per-box outputs (no weather label) |
| Fitting | calibration half of each bin | once, on 21,831 labelled BDD100K train frames |
| Added | — | per-box feature tap; calibrated model; map; label-free estimate of false alarms |
| Choice | Why | Alternatives considered |
|---|---|---|
| Keep the detector frozen; decide after it | calibration stays valid; one detector run serves every setting; no retraining per condition | domain adaptation (DA-Detect: 20.41 vs 21.44 AP@50 on real DAWN fog in Phase 1); fine-tuning (invalidates every calibration) |
| Trade-off as , false alarms per avoided miss | use case sets the balance; the optimal rule is explicit (Eq. 4 ); and map onto it | fixed only (baseline, false alarms unpriced); maximise (one fixed balance); FPPI cap |
| Decide per detection | 87–91% of a per-image oracle’s advantage on BDD100K is chance; the learnable signal is in individual boxes | per-image thresholds from pixels, from the confidence profile, or from YOLOv8x image features (all failed pre-registered tests); box-combination rules; summed-confidence maps |
| One threshold kept as the simple option | one auditable number per ; per-weather thresholds give no gain (0.98–1.03 the cost) | per-weather thresholds (the baseline’s form) |
| Gradient-boosted trees on detector outputs | tabular inputs; trains in minutes on CPU; calibrated without post-hoc scaling (expected calibration error 0.11 points on BDD100K val) | recalibrating the score alone (this is Option A); a neural head; retraining YOLOv8x’s head |
| YOLOv8x’s own per-box outputs as features | pre-registered gain: cost 0.972 (0.969–0.975) of the context-only model on BDD100K, not worse on DAWN (0.995) | context features only (model 1); a separate CNN on box crops (more compute) |
| Matching / conf. loss / loc. loss-set / class set | Source | Confidence | Localization | Classification | Global | ||||
|---|---|---|---|---|---|---|---|---|---|
| size | risk | size | risk | size | risk | risk | |||
| F1 | Hausdorff / bc-recall / pixel-add / APS | Paper | 11.71 | 0.019 | 3.87 | 0.049 | 41.73 | 0.043 | 0.082 |
| Ours, full | 11.53 | 0.020 | 1.30 | 0.053 | 40.64 | 0.042 | 0.085 | ||
| Ours, 300/300 | 11.11 | 0.025 | 1.30 | 0.040 | 42.67 | 0.033 | 0.066 | ||
| F2 | LAC / bc-thresh / pixel-add / LAC | Paper | 18.86 | 0.012 | 20.64 | 0.047 | 0.72 | 0.049 | 0.086 |
| Ours, full | 18.02 | 0.015 | 17.69 | 0.047 | 0.75 | 0.046 | 0.083 | ||
| Boxes scored | AP | AP50 | AP75 |
|---|---|---|---|
| Ultralytics model table (paper’s detector) | 53.9 | – | – |
| Ours: Ultralytics predict, NMS IoU 0.7 per class | 53.2 | 69.8 | 58.0 |
| Ours: Ultralytics predict, class-agnostic NMS 0.5 | 51.6 | 68.8 | 55.6 |
| Ours: cods wrapper, batch 1 (SeqCRC input) | 45.1 | 65.9 | 48.2 |
| Ours: cods wrapper, batch 8 | 10.7 | 32.1 | 1.4 |
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
Autonomous Driving
Autonomous driving develops vehicles that perceive road scenes, predict interactions, and plan and control safe movement with limited or no human input.
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