1. An image processing apparatus for converting the resolution of an original image in such a manner as to increase the spatial resolution of said original image by a factor of Z in each of vertical and horizontal directions, said image processing apparatus comprising: energy calculating means for calculating local energy of said original image; detection means for detecting the direction of an edge on the basis of said local energy calculated by said energy calculating means; interpolation means for interpolating a new pixel from a pixel of said original image on the basis of the direction of the edge detected by said detection means; and edge enhancement means for performing an edge enhancement process on the basis of said local energy calculated by said energy calculating means.