1. An imaging system comprising: a first edge-detecting module configured to detect one or more edge coordinates of at least a reference line in a first image; a first disparity-estimating module configured to obtain a current line of a first estimated disparity map of the first image relative to a second image; and a first edge-refining module configured to refine one or more edge coordinates of the current line of the first estimated disparity map using the one or more edge coordinates of the reference line of the first image to obtain a current line of a first refined disparity map.