[yial]

Newer cars read the outside temperature, and adjust the auto. I don’t know if they sense condensation on the inside. I know that they sense water on the outside to automatically engage wipers.

I have found even the best ones though, to get the rear defrost right, but fail to get front defrost correct in high humidity conditions that aren’t just normal rain. (Very dense fog, snow, sleet ).

[genewitch]

Subaru front facing cameras just shut off the eye sight system when the window fogs. The defrost selection is a button, which means it's computer controlled.

In theory the computer knows when it needs defrost.