Batch active learning (BAL) is a crucial technique for reducing labeling costs and improving data efficiency in training large-scale deep learning models. Traditional BAL methods often rely on metrics like Mahalanobis Distance to balance uncertainty and diversity when selecting data for annotation. However, these methods predominantly focus on the distribution of unlabeled data and fail to leverage feedback from labeled data or the model's performance. To address these limitations, we introduce TrustSet, a novel approach that selects the most informative data from the labeled dataset, ensuring a balanced class distribution to mitigate the long-tail problem. Unlike CoreSet, which focuses on maintaining the overall data distribution, TrustSet optimizes the model's performance by pruning redundant data and using label information to refine the selection process. To extend the benefits of TrustSet to the unlabeled pool, we propose a reinforcement learning (RL)-based sampling policy that approximates the selection of high-quality TrustSet candidates from the unlabeled data. Combining TrustSet and RL, we introduce the Batch Reinforcement Active Learning with TrustSet (BRAL-T) framework. BRAL-T achieves state-of-the-art results across 10 image classification benchmarks and 2 active fine-tuning tasks, demonstrating its effectiveness and efficiency in various domains.
Figures & tables
Figure 1: An overview of the BRAL-T framework, which consists of two main processes: (1) Active Learning for data selection. (2) Reinforcement Learning to approximate TrustSet selection.
Figure 2: Details of BRAL-T. (a) Active Learning Process: πϕi selects the subset Si from Ui for the oracle to annotate, and the model MθLi+1 is trained on Si∪Li . (b) RL process: we sample L and U from Li+1 to train policy πϕi+1 .
Figure 3: Reinforcement learning process. We use U0 as an example for process in the figure.
Methods
FashionMNIST
EMNIST
CIFAR10
CIFAR100
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
LossPrediction
0.859
0.888
0.762
0.793
0.837
0.911
0.481
0.655
WAAL
0.861
0.891
0.808
0.831
0.842
0.883
0.460
0.594
RandomSample
0.844
0.874
0.804
0.828
0.832
0.902
0.517
0.650
BRAL-T
0.863
0.894
0.813
0.833
0.847
0.916
0.525
0.662
Table 1: Experiment results of image classification task on 8 benchmarks.
Figure 4: Visualization of experiment results on Cifar10, Cifar10-imb, Cifar100 and FashionMNIST.
Methods
Cifar10-LT-r10
Cifar10-LT-r20
Cifar100-LT-r10
Cifar100-LT-r20
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
TiDAL
0.510
0.619
0.435
0.583
0.398
0.450
0.365
0.420
SIMILAR
0.507
0.654
0.431
0.566
0.405
0.514
0.366
0.460
LossPrediction
0.478
0.679
0.413
0.585
0.424
0.516
0.380
0.460
WAAL
0.510
0.623
0.435
0.589
0.381
0.458
0.342
0.412
RandomSample
0.476
0.686
0.397
0.587
0.382
0.463
0.343
0.410
Table 2: Experiment results on Cifar10-LT and Cifar100-LT datasets.
Table 7
Appendix figures & tables10 assets
Supplementary material from the paper’s appendix.
Appendix
Benchmarks
∣L0∣
∣U0∣
Q
b
#e
C
FashionMNIST
500
59,500
10,000
250
40
10
EMNIST
1,000
696,932
50,000
500
40
62
CIFAR10
1,000
49,000
40,000
500
50
10
CIFAR100
1,000
49,000
40,000
500
60
100
CIFAR10-imb
1,000
27,239
20,000
500
50
10
CIFAR10-LT
1,000
-
∣D∣
100
50
10
Appendix
Table 5: Setting of benchmarks. Where ∣L0∣ refers to size of initial labeled set, ∣U0∣ refers to size of initial unlabeled data pool, Q refers to budget, b refers to batch size for target model training, #e refers to number of epoch for target model training and C refers to number of clusters from unlabeled data pool. For all the benchmarks, the number of clusters M from labeled dataset is set to be the same as C and number of candidate action for Uc is set to be 5.
Methods
FashionMNIST
EMNIST
CIFAR10
CIFAR100
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
AUBC
F-acc
LossPrediction
± 0.002
± 0.038
± 0.016
± 0.022
± 0.006
± 0.012
± 0.019
± 0.012
WAAL
± 0.002
± 0.015
± 0.012
± 0.015
± 0.006
± 0.009
± 0.006
± 0.011
RandomSample
± 0.001
± 0.009
± 0.004
± 0.007
± 0.003
± 0.011
± 0.003
± 0.008
BRAL-T
± 0.001
± 0.008
± 0.005
± 0.014
± 0.003
± 0.006
± 0.004
± 0.009
Appendix
Table 6: Confidence Interval of Experiment results of image classification task.
Figure 5: Time Cost of BRAL-T and baselines.
Figure 6: Pairwise Comparison of BRAL-T, VAAL, SAAL and BAIT.
Method
AUBC
F-Acc
LossPrediction
0.748
0.848
WAAL
0.752
0.799
RandomSample
0.710
0.810
BRAL-T
0.762
0.851
BRAL-T (two agents)
0.755
0.837
Appendix
Table 7: BRAL-T reusing two RL agents.
Figure 7: Accuracy-budget curve of Different Initial Labeled Set Quality.
Initial Method
AUBC
F-Acc
Random
0.762
0.851
Twisted Main
0.750
0.855
Twisted Rare
0.756
0.855
Appendix
Table 8: Experiment Result of Different Initial Labeled Set Quality.
Figure 8: Comparison between BRAL-T with RL policy and Ground Truth Labels.
# Actions
AUBC
F-Acc
5
0.762
0.851
10
0.763
0.853
50
0.755
0.851
100
0.758
0.854
Appendix
Table 9: Ablation Study on Different Candidate Action Number.
λ
AUBC
F-Acc
0.25
0.762
0.851
1.00
0.752
0.842
2.00
0.749
0.830
Appendix
Table 10: Impact of λ value on CIFAR10-imb dataset.