Patent ID: 7171031

Claim:
A phase information restoring method of restoring phase information of radiation transmitted through an object on the basis of an image signal obtained by detecting intensity of the radiation transmitted through the object, said method comprising the steps of: (a) obtaining at least three first differential signals representing differentials between one image signal and another image signal on the basis of at least four image signals obtained by detecting intensity of radiation on at least four planes that are parallel and positioned at different distances from the object, said at least four image signals respectively representing radiation image information on said at least four planes; (b) obtaining second differential signals and third differential signals representing differentials between image signals relative to two directions orthogonal to each other within said planes with respect to at least three image signals; (c) obtaining a Laplacian of phase on the basis of the at least three image signals and at least three sets of the first to third differential signals; and (d) performing inverse Laplacian operation on the Laplacian of phase so as to restore phase information.