Fast and Direct Polygonization for Gray-Scale Images Using Digital Straightness and Exponential Averaging

Although there exist various algorithms for polygonization of objects present in a digital image, most of them cannot directly be applied on a gray-scale image without resorting to edge map computation, thinning, etc. Hence, with the aim of applying polygonization directly on a gray-scale image, we propose here an improved algorithm. It is based on a novel proposition of exponential averaging of estimated edge strengths, which is used to extract (thinned) digitally straight edges directly from a gray-scale image. These straight edges are subsequently used as input for a fast polygonization based on simple primitive operations in the integer domain. Procedural advantages and implementation details of the proposed method are explained in this paper to adjudge its fitness in the context of polygonization. Experimental results have been furnished to demonstrate the usefulness, efficiency, and robustness of the proposed technique.