As apu points out, this is really well understood now -- has been for over 10 years, in fact. I think the fact that projectors are still fairly expensive (thou

As apu points out, this is really well understood now -- has been for over 10 years, in fact. I think the fact that projectors are still fairly expensive (though much cheaper than years ago) and most researchers aren't big participants in the open source community is why we don't have anything widespread. At the University of Kentucky lab where I worked in 2002 (The Metaverse Lab), we had a 24-projector geometrically/photometrically-corrected only-casually-aligned system projecting on 2 walls and the floor with all 3 planes meeting at a corner. Additionally, the system was cordlessly head-tracked (Intersense) and the world view would dynamically change so that you could look around objects, look under tables, etc. It was amazingly cool. I'm pretty sure I could write the code for the geometric calibration of a 4-6 projector (whatever a single, stationary camera could see most of) single-plane system in a day and then use the homographies (plane-to-plane mappings) to warp and display large images geometrically seamlessly on the multi-projector display. There would still be extremely apparent photometric seams where the projectors overlap, though. You can use some simple models to get rid of some of this, but REALLY making it look good in practice is hard, and requires some engineering. As with most things, making it look 80% good is easy. It's that last 20% that requires years of engineering and a dedicated company like Mersive to make it happen. Their stuff looks good.