What is Region of Interest (ROI) and how is it used?

[nbstl68]

Hi,
I have a QSee system (NVR:QT8516, Cameras:QTN8037B (3MP))
While they do not have a lot of settings, it does have one called "ROI"...In keeping with QSee's apparent commitment to obscurity and lack of documentation, I can find no information on what this is or does or how to use it.
Could someone more knowledgeable please explain its proper use?

Thanks

 

[alastairstevenson]

https://qsee.custhelp.com/app/answe...sion/L3RpbWUvMTQ1MjAyNDc3NC9zaWQveXp6T0FORm0=

 

[nbstl68]

Thanks..even QSEE tech support did not give me that....they sent me a basic cmera setup guide