Flight Dynamics HGS system may be of interest to you
The Boeing 737NG (Next Generation) I fly is equipped with a Flight Dynamics HGS (Head-Up Guidance System). The Combiner I look through has a two position brightness control knob. In the AUTO position the brightness of the presentation in the combiner is controlled by a sensor in the combiner. This allows the visual display viewed through the combiner to stay relatively clear as the pilot transitions from IMC (Instrument meteorological conditions {flying in the clouds & can't see a thing}) to minimum visual references during a low visibility approach.
Boeing makes the jet. Flight Dynamics make the HGS. The manuals I have are written for pilots. Meaning, I can find the information on how to adjust the brightness, but don't have source software/hardware documentation or electrical diagrams available to me.
Many EFIS (Electronic Flight Information Systems) have a sensor that adjusts the brightness of all the displays as the flight progressed through different lighting conditions.
Respectfully,
Northbeach