In this paper, a technique is presented for obtaining polygonal approximation of object contours directly from the edge images. The technique is based on a new formulation of Hough transform (HT) for aggregation of edge points into line segments. The space requirement of the HT is brought down by considering a different parameterization of straight lines. In this method, the process of edge linking and boundary approximation are combined into a single algorithm. Consequently, the scheme is computationally more efficient than the classical boundary approximation techniques which require use of a separate edge linking algorithm for obtaining linked list of edge points as their input. Experimental results presented here highlight the effectiveness of this method for approximating object boundaries of polygonal as well as curved shapes present in the images of complex multi-object scenes. © 1992 IEEE.