This is already "done". See two examples with Omega Centauri by Rick Stevenson:
PCC, average spiral galaxy white reference:
https://www.astrobin.com/299315/E/PCC, average spiral galaxy white reference + correction for galactic dust extinction:
https://www.astrobin.com/299315/F/Vicent Peris already designed the algorithm for galactic extinction correction, and we have been working on the implementation (which is
not trivial—one cannot just apply mapped extinction values pixel by pixel). The main problem here is having a set of reasonably reliable observational data. I plan on using Gaia DR2, which provides
galactic dust extinction data for about 88 million stars.
So you can count on this feature implemented in a future release of the PCC tool. The algorithmic part and its implementation are already designed. I just have to build a suitable database from original Gaia DR2 data files, along with the required code to access it efficiently.