Dynamic thresholding (full)

**Is your feature request related to a problem? Please describe.**
I am trying to increase the variety and quality of my results

**Describe the solution you'd like**
I would like dynamic thresholding implemented

**Describe alternatives you've considered**
Doing it myself, paying someone better than to do it or giving up

**Additional context**
here's the repo: https://github.com/mcmonkeyprojects/sd-dynamic-thresholding/tree/master
here's the relevant code: https://github.com/mcmonkeyprojects/sd-dynamic-thresholding/blob/master/dynthres_core.py
code is short too. less than 200 lines.