The lungs segmentation via UNet model were performed first to take a closer look on data distribution.
Resulted ROI were used then as describtors for clusterisation:
This two resulted clusters actually caught the difference of images came from different sources.
Below are random samples from each of both clusters:
To overcame the domain difference an augmentation technique based on work of Philipsen et al has been employd enorm.py:
Finally RetinaNet model was used along with focal loss:
