| area_center_xld | Area and center of gravity (centroid) of contours and polygons. |
| circularity_xld | Shape factor for the circularity (similarity to a circle) of a contour. |
| compactness_xld | Shape factor for the compactness of a contour. |
| contour_point_num_xld | Return the number of points in an XLD contour. |
| convexity_xld | Shape factor for the convexity of a contour. |
| diameter_xld | Maximum distance between two contour points. |
| dist_ellipse_contour_xld | Distance of contours to an ellipse. |
| eccentricity_xld | Shape features derived from the ellipse parameters. |
| elliptic_axis_xld | Parameters of the equivalent ellipse. |
| fit_circle_contour_xld | Approximation of XLD contours by circles. |
| fit_ellipse_contour_xld | Approximation of XLD contours by ellipses or elliptic arcs. |
| fit_line_contour_xld | Approximation of XLD contours by line segments. |
| get_contour_angle_xld | Calculate the direction of an XLD contour for each contour point. |
| get_contour_attrib_xld | Return point attribute values of an XLD contour. |
| get_contour_global_attrib_xld | Return global attributes values of an XLD contour. |
| get_regress_params_xld | Return XLD contour parameters. |
| info_parallels_xld | Return information about the gray values of the area enclosed by XLD parallels. |
| length_xld | Length of contours or polygons. |
| local_max_contours_xld | Select XLD contours with a local maximum of gray values. |
| max_parallels_xld | Join modified XLD parallels lying on the same polygon. |
| moments_any_xld | Arbitrary geometric moments of contours or polygons. |
| moments_xld | Geometric moments M20, M02, and M11 of contours or polygons. |
| orientation_xld | Orientation of a contour. |
| query_contour_attribs_xld | Return the names of the defined attributes of an XLD contour. |
| query_contour_global_attribs_xld | Return the names of the defined global attributes of an XLD contour. |
| select_contours_xld | Select XLD contours according to several features. |
| select_shape_xld | Select contours using shape features. |
| smallest_circle_xld | Smallest enclosing circle of a contour. |
| smallest_rectangle1_xld | Enclosing rectangle parallel to the coordinate axes. |
| smallest_rectangle2_xld | Smallest enclosing rectangle with arbitrary orientation. |