HALCON Reference Manual 10.0.2

gen_polygons_xldgen_polygons_xldgen_polygons_xldGenPolygonsXldGenPolygonsXld (Operator)

Name

gen_polygons_xldgen_polygons_xldgen_polygons_xldGenPolygonsXldGenPolygonsXld — Approximate XLD contours by polygons.

Signature

gen_polygons_xld(Contours : Polygons : Type, Alpha : )

gen_polygons_xldgen_polygons_xldgen_polygons_xldGenPolygonsXldGenPolygonsXld approximates XLD contours (ContoursContoursContoursContourscontours) by polygons. The type of the approximation can be set by TypeTypeTypeTypetype. The threshold for the approximation is set via AlphaAlphaAlphaAlphaalpha. The procedure is able to process open as well as closed contours. The resulting approximating XLD polygons are returned in PolygonsPolygonsPolygonsPolygonspolygons.

Contours can be approximated by the algorithms of Ramer, Ray, and Sato. The algorithm of Ramer approximates contours such that the Euclidian distance of the approximating polygon to the contour is at most AlphaAlphaAlphaAlphaalpha pixel units. The algorithm of Ray does not need a threshold, and hence AlphaAlphaAlphaAlphaalpha is ignored. Here, the contour is approximated by maximizing the line length, while minimizing the sum of the distances of the line segment from the contour. The algorithm of Sato produces a polygon point at the point of the contour in which the distance to the end points of the contour is maximal. The total approximation error for each iteration is then given by (L - L')/L, where L is the Euclidian contour length, and L' is the length of the approximating polygon.