I make confusing road signs

I've got some result for my phd to show today. Take a road sign and swap the direction.
With 4 points correspondance, it's rather straight forward to compute the projective relationship (homography) between two planar surfaces. The novelty of this work is the smooth and perspectively correct interpolation of the transition.

You might have seen planar surfaces flying around in space in other animation work before. The difference is that those work are done in 3D space so the 3D coordinates of the objects need to be specified and then the scene projected (rendered) on 2D screen. Mine works in 2D - a 2D photograph and some corner points as input, the algorithm works out the homography, decompose it into perspective, scale, rotation and translation components and interpolates the picture properly.

Cool! I think it is.

I created a related page on my CSSE website here with animated gif.
Projective interpolation for animation