Corneal Topography: Constructing Curvature Topography from Placido Rings Image

This code constructs Curvature Topography from Placido Rings Image.
This is the implementation uses many concepts from the paper, "Open-access operating algorithms for commercial videokeratographer and improvement of corneal sampling" by Julián Espinosa, David Mas, Jorge Pérez, and Ana Belén Roig.

Presently, this is a very primitive implementation and isn't robust enough to handle broken placido ring images. This needs to be fixed for in future.