Provided are an input device and an image processing method thereof. The image processing method of the input device having a scan function includes acquiring a first image frame and a second image frame to detect coordinates of the acquired first image frame and coordinates of the acquired second image frame; dividing an overlap region between the first image frame and the second image frame into a plurality of sub overlap regions by using the detected coordinates of the first and second image frames; dividing each of the sub overlap regions into unit regions; setting a reference feature point of a plurality of feature points within the divided unit regions; and extracting corresponding points by using the set reference feature point.