1. A three dimensional (3D) motion recognition method through feature-based stereo matching, comprising: obtaining a plurality of images from a plurality of cameras; extracting feature points from a single reference image; and comparing and tracking the feature points of the reference image and another comparison image photographed at the same time using an optical flow method; wherein the optical flow method is capable of modifying a size and a shape of a window used in the optical flow method by using previous information.