ValueError: zero-size array to reduction operation minimum which has no identity

Hi,
Thank you for your excellent work at first!

When I use persam.py on my own dataset (a medical image dataset), I get the following error
> ValueError: zero-size array to reduction operation minimum which has no identity

Apparently, SAM predicts an empty mask, what could be buggy about this?
Your excellent will be a great help to my research! 