Account for partial volume effects using SoftSeg training

[uzaymacar]

As discussed in the meeting, we will check if SoftSeg can enhance our lesion segmentation model's performance.

To-do:

• Train and test lesion segmentation with softseg
• Update the release with the new lesion segmentation model that works best among current config vs. current config + softseg

[uzaymacar]

I trained soft segmentation models for lesion segmentation as discussed in #40. The results I got are presented in this document. Currently it would be fair to say that we don't observe a performance gain with soft segmentation.