I think the final product and the ideas and concepts that it holds are the important aspect for copyright.
If I cut up a Star Wars poster into 1,000,000 tiny pieces, and then reassemble them into a self portrait with no reference whatsoever to Star Wars and sell it, would I have committed copyright infringement?
If I did the same thing but made a stormtrooper out of the pieces, is the copyright issue with the source material, or the final product?