1. A method for generating a large-field, high-resolution image of an object, said method comprising the steps of: (a) generating a first optical scene representative of a first portion of the object by: spatially filtering a first portion of an incident X-ray field with a spatial filter to generate a first, two-dimensional X-ray sub-field; projecting the first X-ray sub-field through the first portion of the object and then through an X-ray-to-optical conversion screen to produce the first optical scene; and, directing the first optical scene with a reflecting assembly onto an optical detector to generate a two-dimensional sub-image of the first portion of the object; (b) rotating both the spatial filter and the reflecting assembly; (c) generating a second optical scene representative of a second portion of the object by: spatially filtering a second portion of the incident X-ray field with the rotated spatial filter to generate a second, two-dimensional X-ray sub-field; projecting the second x-ray sub-field through the second portion of the object and then through the X-ray-to-optical conversion screen to produce the second, optical scene; and, directing the second optical scene with the rotated reflecting assembly onto the optical detector to generate a two-dimensional sub-image of the second portion of the object; and, (d) combining all two-dimensional sub-images to form a large-field, high-resolution image of the object.