1. A medical image registration method comprising: determining whether a reference point corresponding to a position of a given anatomical entity of an object is present in a first medical image and a second medical image of the object; in response to the determining that the reference point is not present, indicating that the given anatomical entity is not captured, in at least one among the first medical image and the second medical image, estimating a virtual reference point corresponding to the position of the given anatomical entity relative to the at least one among the first medical image and the second medical image, in which the reference point is not present, by using anatomical information of the object; and registering the first medical image and the second medical image by using the estimated virtual reference point.