The central figure has been widely identified as God the Father overseeing the story of Salvation. He wears a papal tiara an attribute normally associated with the Father.
Please mention this source: The Ghent Altarpiece: panel Christ detail, by Jan van Eyck; Hubert van Eyck, collection Sint-Baafskathedraal Gent, artinflanders.be, photo: Hugo Maertens, Contractuele beperkingen.