Rectangular Building Auto Extraction of Digital City

In order to reduce the scope of characteristic dot extracting and matching in 3D reconstruction of digital city based on video,an auto building regional extraction algorithm was proposed.It attained lines array using Hough transform for the preprocessed image,and applied DotDensity proposed and the values of counter in Hough space analyzing relation between contours’ geometrical position to get the contour line segments.Experimental results present that using the proposed DotDensity can eliminate disturbing lines effectively and the approach can get acceptable results fast from images using different extracting methods for vertical and horizontal boundaries with less complicated backgrounds even if the building deforms in picture due to shooting angle.