Robert Sarosi from erLab posts erLab_edgeBlender script for After Effects which helps make edge-blended panoramic projections for projector based images and panoramas. Check out the script for Creating edge-blended Panoramic Projections in After Effects here.
from the description: Edge blending is a clever solution to build up panoramic projections with 2 or more projectors. Some very expensive projectors include this capability and with play-out softwares that can mimic it programmatically. But if you don’t have one of these high end projectors you need to find some other solution. At an event this happened to us too. They were expensive projectors but one of them lacked this feature. So we developed this script to solve this problem. And cheaply!