sampling rule for the fully-labeled dataset

[qjadud1994]

Thank you for sharing your great work, GroupRCNN for WSSOD.

As in the below figure, GroupRCNN is trained with a subset (10% or 20% or 50%) of COCO fully-labeled datasets.

Are there any rules or algorithms to sample a subset of COCO fully-labeled datasets? For example, when randomly sampling 10% of fully-labeled datasets, the minor (long-tailed) classes are rarely included in the 10% sampled dataset.

Did you consider the distribution of categories when sampling the COCO dataset or do you have any special rules for sampling the dataset?