Faster RCNN class-wise output and the number of labels

Question

I am applying pretrained Faster RCNN model on my custom dataset and wonder if there are any ways that I can look at the number of labels in all output images by class.

I am refering the github below: https://github.com/sovit-123/fastercnn-pytorch-training-pipeline

Thanks for your help!

I tried to search online but havent figured out anything useful.

Figure 1