In order to get rid of the edge points which are not related to line detection,obtain complete line edge points and extract line segments accurately,a new line segment extraction method based on predicted direction search and edge curvature constraint is proposed.Firstly,the dual-threshold method is employed to detect the edge points of the target to track its edge contour.Meanwhile,the direction information contained in the edge points generated by the latest tracking of edge points is used to predict the search direction of the next edge point.The depth-first search method is used to cross the break points along the predicted direction and continue to search the edge points,which effectively avoids wrong selection of bifurcation paths and ensures a more complete edge contour.Secondly,the curvature and length constraints of the edge are employed to extract the edge points of the line segments in the edge contours.Finally,the line segments are fitted by using the edge points of the line segments,and the final line segments are obtained by merging the discrete line segments.The experimental results show that the proposed method can effectively deal with edge fracture and bifurcation,extract complete line segments and end-point information accurately and quickly.The performance of the proposed method is superior to that of the existing line segment extraction methods.