1. An image correcting method comprising: attaching a marker to an object, and generating a first non-real-time image and a first real-time image including the object's anatomical information about a surrounding region including a position of the marker when the object is in a first pose; generating a second real-time image of the object about the surrounding region when the object is in a second pose; obtaining shift information of the marker based on the first real-time image and the second real-time image when the object is changed from the first pose to the second pose; and correcting the first non-real-time image based on the shift information of the marker.