1. A stereo matching method, comprising: investigating a pattern according to a predetermined period; obtaining left and right stereo images in which the investigated pattern is included or not included; determining whether each of the stereo image (n-th frame, n is a natural number of 1 or more) obtained according to the predetermined period and a buffering image (n−1-th frame) that is a previous frame image of the stereo image includes the pattern; and generating a final cost volume by performing different image processing according to whether each of the stereo image and the buffering image includes the pattern.