Incremental PO diffraction solution for arbitrarily curved surfaces

This paper present a formulation to extend the representation of PO for arbitrarily curved surfaces in terms of truncated GO contribution plus a line integration of incremental PO (IPO) contributions along the shadow boundary contour of the illuminated surface. This formulation fits well both a PTD and a ITD scheme when corrected by the fringe contributions, and lies the basis to formulate ITD diffraction contributions that directly compensate through line integration the GO disappearance without resorting to a fringe scheme. The derivation, presented here for the scalar case, constitutes the basic step for the extension to the electromagnetic case.