SSUL: Semantic Segmentation with Unknown Label for Exemplar-based Class-Incremental Learning
Sungmin Cha1,2*, Beomyoung Kim3*, YoungJoon Yoo2,3, Taesup Moon1
* Equal contribution
1 Department of Electrical and Computer Engineering, Seoul National University
2 NAVER AI Lab
3 Face, NAVER Clova
NeurIPS 2021
This paper introduces a solid state-of-the-art baseline for a class-incremental semantic segmentation (CISS) problem. While the recent CISS algorithms utilize variants of the knowledge distillation (KD) technique to tackle the problem, they failed to fully address the critical challenges in CISS causing the catastrophic forgetting; the semantic drift of the background class and the multi-label prediction issue. To better address these challenges, we propose a new method, dubbed SSUL-M (Semantic Segmentation with Unknown Label with Memory), by carefully combining techniques tailored for semantic segmentation. Specifically, we claim three main contributions. (1) defining unknown classes within the background class to help to learn future classes (help plasticity), (2) freezing backbone network and past classifiers with binary cross-entropy loss and pseudo-labeling to overcome catastrophic forgetting (help stability), and (3) utilizing tiny exemplar memory for the first time in CISS to improve both plasticity and stability. The extensively conducted experiments show the effectiveness of our method, achieving significantly better performance than the recent state-of-the-art baselines on the standard benchmark datasets. Furthermore, we justify our contributions with thorough ablation analyses and discuss different natures of the CISS problem compared to the traditional class-incremental learning targeting classification.
Method | VOC 10-1 (11 tasks) | VOC 15-1 (6 tasks) | VOC 5-3 (6 tasks) | VOC 19-1 (2 tasks) | VOC 15-5 (2 tasks) | VOC 5-1 (16 tasks) | VOC 2-1 (19 tasks) |
---|---|---|---|---|---|---|---|
MiB | 12.65 | 29.29 | 46.71 | 69.15 | 70.08 | 10.03 | 9.88 |
PLOP | 30.45 | 54.64 | 18.68 | 73.54 | 70.09 | 6.46 | 4.47 |
SSUL | 59.25 | 67.61 | 56.89 | 75.44 | 71.22 | 48.65 | 38.32 |
SSUL-M | 64.12 | 71.37 | 58.37 | 76.49 | 73.02 | 55.11 | 44.74 |
Method | ADE 100-5 (11 tasks) | ADE 100-10 (6 tasks) | ADE 100-50 (2 tasks) | ADE 50-50 (3 tasks) |
---|---|---|---|---|
MiB | 25.96 | 29.24 | 32.79 | 29.31 |
PLOP | 28.75 | 31.59 | 32.94 | 30.40 |
SSUL | 32.48 | 33.10 | 33.58 | 29.56 |
SSUL-M | 34.56 | 34.46 | 34.37 | 29.77 |
- torch>=1.7.1
- torchvision>=0.8.2
- numpy
- pillow
- scikit-learn
- tqdm
- matplotlib
data_root/
--- VOC2012/
--- Annotations/
--- ImageSet/
--- JPEGImages/
--- SegmentationClassAug/
--- saliency_map/
--- ADEChallengeData2016
--- annotations
--- training
--- validation
--- images
--- training
--- validation
Download SegmentationClassAug and saliency_map
DATA_ROOT=your_dataset_root_path
DATASET=voc
TASK=15-1 # [15-1, 10-1, 19-1, 15-5, 5-3, 5-1, 2-1, 2-2]
EPOCH=50
BATCH=32
LOSS=bce_loss
LR=0.01
THRESH=0.7
MEMORY=100 # [0 (for SSUL), 100 (for SSUL-M)]
python main.py --data_root ${DATA_ROOT} --model deeplabv3_resnet101 --gpu_id 0,1 --crop_val --lr ${LR} --batch_size ${BATCH} --train_epoch ${EPOCH} --loss_type ${LOSS} --dataset ${DATASET} --task ${TASK} --overlap --lr_policy poly --pseudo --pseudo_thresh ${THRESH} --freeze --bn_freeze --unknown --w_transfer --amp --mem_size ${MEMORY}
DATA_ROOT=your_dataset_root_path
DATASET=ade
TASK=100-5 # [100-5, 100-10, 100-50, 50-50]
EPOCH=100
BATCH=24
LOSS=bce_loss
LR=0.05
THRESH=0.7
MEMORY=300 # [0 (for SSUL), 300 (for SSUL-M)]
python main.py --data_root ${DATA_ROOT} --model deeplabv3_resnet101 --gpu_id 0,1 --crop_val --lr ${LR} --batch_size ${BATCH} --train_epoch ${EPOCH} --loss_type ${LOSS} --dataset ${DATASET} --task ${TASK} --overlap --lr_policy warm_poly --pseudo --pseudo_thresh ${THRESH} --freeze --bn_freeze --unknown --w_transfer --amp --mem_size ${MEMORY}
Our implementation is based on these repositories: DeepLabV3Plus-Pytorch, Torchvision.
SSUL
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