Input device and image processing method thereof

An input device having a scan function, the input device comprising:

• a scanner acquiring a first image frame and a second image frame;
• a coordinate detector detecting coordinates of the acquired first image frame and coordinates of the acquired second image frame;
• a region divider 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, the region division unit dividing each of the sub overlap regions into unit regions;
• a reference feature point setter setting a reference feature point of a plurality of feature points within the divided unit regions;
• a corresponding point extractor extracting corresponding points by using the set reference feature point;
• a perspective transformer perspectively transforming the first and second image frames by using the extracted corresponding points;
• and
• an image merger merging the perspectively transformed first and second image frames,
• wherein the region divider divides each of the sub overlap regions into a plurality of first unit regions,
• wherein the reference feature point setter sets a first reference feature point of the plurality of feature points within each of the first unit regions, and
• wherein the input device further comprises:
• a controller removing the other feature point when the other feature point except for the first reference feature point exists within each of the first unit regions after the other feature point except for the first reference feature point exists within each of the first unit regions.