1. A method comprising: identifying a motion vector of an unwanted object in preview frames of a desired image obtained by a camera; setting a photographing interval in accordance with the motion vector, wherein the motion vector comprises a size of the unwanted object and a speed of the unwanted object; photographing continuous frames of the desired image in accordance with the photographing interval; and removing the unwanted object from the desired image so as to restore a background behind the unwanted object using the continuous frames and the photographing interval, wherein setting the photographing interval comprises: identifying the size of the unwanted object as it moves; and analyzing the size of the unwanted object and the speed of the unwanted object, wherein setting the photographing interval further comprises: dividing the size of each unwanted object with the motion vector of each unwanted object; and identifying a maximum photographing frames per second based at least partially on a slowest unwanted object having a largest size.