Here's a view from inside my right eye, as I see on a temperature scale (black is cold; white is hot)

The rooftop kettle that heats up the asphalt derives its flame from a propane tank. The tank is on its side on the roof in front of the kettle.

Fire and ice: here the propane tank and hose show up as the blackest objects in the scene because of the Joule Thomson effect (expanding propane gas cools, causing ice to form on the tank and hose):

Now I grab the mop:

the bucket of hot asphalt (approx. 500 degrees) shows up as white:

The wearer can see (and so can a remote expert who can also comment on) areas where the coverage is poor:

After good coverage with asphalt, the base sheet is rolled down:

After the base sheet is rolled down, the eyeglasses provide a sort of "x-ray vision" in which the wearer can see through the various layers of the roof to make certain that the materials were applied properly: