1. An apparatus for generating a virtual view in an image reconstruction system, the apparatus comprising: a receiver which receives original view projection images that are generated by emitting X-rays toward an object via original views; a three-dimensional (3D) reconstruction generator which generates a 3D object by three-dimensionally reconstructing the object by using the original view projection images; a reprojection image generator which generates original view reprojection images by virtually emitting X-rays toward the reconstructed 3D object via the original views; a motion estimator which estimates a motion of the reconstructed 3D object with respect to at least two of the original view reprojection images by using a motion estimation scheme; and an intermediate view generator which generates an intermediate view projection image with respect to the at least two of the original view reprojection images by using information relating to the at least two of the original view reprojection images that is estimated by the motion estimator.