RandMSAugment: A Mixed-Sample Augmentation for Limited-Data Scenarios
Swarna Kamlam Ravindran Carlo Tomasi
The high costs of annotating large datasets suggests a need for effectively
training CNNs with limited data, and data augmentation is a promising
direction. We study foundational augmentation techniques, including Mixed
Sample Data Augmentations (MSDAs) and a no-parameter variant of RandAugment
termed Preset-RandAugment, in the fully supervised scenario. We observe that
Preset-RandAugment excels in limited-data contexts while MSDAs are moderately
effective. We show that low-level feature transforms play a pivotal role in
this performance difference, postulate a new property of augmentations related
to their data efficiency, and propose new ways to measure the diversity and
realism of augmentations. Building on these insights, we introduce a novel
augmentation technique called RandMSAugment that integrates complementary
strengths of existing methods. RandMSAugment significantly outperforms the
competition on CIFAR-100, STL-10, and Tiny-Imagenet. With very small training
sets (4, 25, 100 samples/class), RandMSAugment achieves compelling performance
gains between 4.1% and 6.75%. Even with more training data (500 samples/class)
we improve performance by 1.03% to 2.47%. RandMSAugment does not require
hyperparameter tuning, extra validation data, or cumbersome optimizations.