If you intend to scan overlapping sections of the poster or carefully take overlapping photos of the poster (be sure that the camera stays the same distance from the poster for all the photos - you may want to use a tripod to put your camera on if you go
this route) then yes, ICE should be able to solve your overlapping scans or photos of the poster as a planar panorama.
If you run into any problems with your project, write back and maybe the rest of us can help you figure your scenario out.
Your fellow panner,
N