how to solve data imbalance

[Aslizy]

Hi,

I wonder what if for certain digits, I have more diverse samples in the dataset, for the rest, I have less diverse samples. In the current implementation and also the paper, I feel like the digit classifiers do not have knowledge transfer with regards to digit recognition. Is there any approaches to tackle with this kind of data imbalance problem? Or any transfer learning could be done here? Many thanks.