Another "real" technique I've seen is having sensors that do not have the individual phototransistors layed out in a nice periodic grid pattern but with aperiodic pattern like Penrose tiling (put PTs as vertices of kites/darts).

The interpolation techniques (making a photo out of hardware input) manage to get 10-15x more resolution out of that sensor layout compared to normal grid.

You also avoid Moire patterns with that too.