1. A computer implemented method comprising: providing dictionary image data including a recognition target pattern, a plurality of feature points of the recognition target pattern including a size (R m ) and direction (θ m ) of a feature vector, and an offset (O x , O y ) from coordinates at a center of a target image to coordinates of a feature point; providing a size (R t ) and direction (θ t ) of the feature vector for coordinates (T x , T y ) of a plurality of feature points in the target image; calculating coordinates (F x , F y ) of a virtual center point in the target image derived from T x , T y , O x , O y , R m , R t , θ m , and θ t ; counting a number of additional virtual center points within a predetermined radius (r) of the coordinates (F x , F y ) of the virtual center point; and storing the coordinates (F x , F y ) of the virtual center point and the number of counted virtual center points.