Name
elliptic_axis_points_xldelliptic_axis_points_xldEllipticAxisPointsXldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXld — Parameters of the equivalent ellipse of contours or polygons treated as
point clouds.
Herror elliptic_axis_points_xld(const Hobject XLD, double* Ra, double* Rb, double* Phi)
Herror T_elliptic_axis_points_xld(const Hobject XLD, Htuple* Ra, Htuple* Rb, Htuple* Phi)
Herror elliptic_axis_points_xld(Hobject XLD, double* Ra, double* Rb, double* Phi)
Herror elliptic_axis_points_xld(Hobject XLD, HTuple* Ra, HTuple* Rb, HTuple* Phi)
double HXLD::EllipticAxisPointsXld(double* Rb, double* Phi) const
HTuple HXLDArray::EllipticAxisPointsXld(HTuple* Rb, HTuple* Phi) const
void EllipticAxisPointsXld(const HObject& XLD, HTuple* Ra, HTuple* Rb, HTuple* Phi)
HTuple HXLD::EllipticAxisPointsXld(HTuple* Rb, HTuple* Phi) const
double HXLD::EllipticAxisPointsXld(double* Rb, double* Phi) const
The operator elliptic_axis_points_xldelliptic_axis_points_xldEllipticAxisPointsXldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXld calculates the radii
(RaRaRaRaRara, RbRbRbRbRbrb) and the orientation (PhiPhiPhiPhiPhiphi, in radians)
of the ellipse
having the same orientation and the same aspect ratio as the point cloud
given by the contour or polygon
XLDXLDXLDXLDXLDXLD (i.e., the order of the points in the contour or
polygon is not taken into account). If the contour or
polygon is closed (end point = start point), the end point of the contour or
polygon is not taken into account to avoid that it receives twice
the weight of the other points.
Calculation:
If the moments M20, M02 and M11 are
normalized to the area (see moments_points_xldmoments_points_xldMomentsPointsXldmoments_points_xldMomentsPointsXldMomentsPointsXld),
the major radius RaRaRaRaRara and minor radius RbRbRbRbRbrb are
calculated as:
RaRaRaRaRara = sqrt(8.0*(M20+M02+sqrt((M20-M02)^2+4.0*M11^2)))/2.0
RbRbRbRbRbrb = sqrt(8.0*(M20+M02-sqrt((M20-M02)^2+4.0*M11^2)))/2.0
The orientation PhiPhiPhiPhiPhiphi, i.e., the angle between the major axis
and the x (column) axis, is defined by:
PhiPhiPhiPhiPhiphi = -0.5 * atan2(2.0 * M11,M02 - M20)
elliptic_axis_points_xldelliptic_axis_points_xldEllipticAxisPointsXldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXld should be used if the contour XLDXLDXLDXLDXLDXLD
intersects itself or if it is not possible to close the contour using a line
from end to start point without self-intersection, because in this case
elliptic_axis_xldelliptic_axis_xldEllipticAxisXldelliptic_axis_xldEllipticAxisXldEllipticAxisXld does not produce useful results. To test whether
the contours or polygons intersect themselves,
test_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld can be used.
If more than one contour or polygon is passed, the results are stored
in tuples in the same order as the respective contours or polygons in
XLDXLDXLDXLDXLDXLD.
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
Contours or polygons to be examined.
RaRaRaRaRara (output_control) real(-array) → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)
Major radius.
Assertion: Ra >= 0.0
RbRbRbRbRbrb (output_control) real(-array) → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)
Minor radius.
Assertion: Rb >= 0.0 && Rb <= Ra
Angle between the major axis and the column axis
(radians).
Assertion: - pi / 2 < Phi && Phi <= pi / 2
Let n be the number of points of the contour or polygon.
Then the run time is O(n).
elliptic_axis_points_xldelliptic_axis_points_xldEllipticAxisPointsXldelliptic_axis_points_xldEllipticAxisPointsXldEllipticAxisPointsXld returns 2 (H_MSG_TRUE) if the input is not
empty. If the input is empty the behavior can be set via
set_system(::'no_object_result',<Result>:)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary,
an exception is raised.
gen_contours_skeleton_xldgen_contours_skeleton_xldGenContoursSkeletonXldgen_contours_skeleton_xldGenContoursSkeletonXldGenContoursSkeletonXld,
edges_sub_pixedges_sub_pixEdgesSubPixedges_sub_pixEdgesSubPixEdgesSubPix,
threshold_sub_pixthreshold_sub_pixThresholdSubPixthreshold_sub_pixThresholdSubPixThresholdSubPix,
gen_contour_polygon_xldgen_contour_polygon_xldGenContourPolygonXldgen_contour_polygon_xldGenContourPolygonXldGenContourPolygonXld,
test_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXld
area_center_points_xldarea_center_points_xldAreaCenterPointsXldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXld,
gen_ellipse_contour_xldgen_ellipse_contour_xldGenEllipseContourXldgen_ellipse_contour_xldGenEllipseContourXldGenEllipseContourXld
elliptic_axis_xldelliptic_axis_xldEllipticAxisXldelliptic_axis_xldEllipticAxisXldEllipticAxisXld,
smallest_rectangle2smallest_rectangle2SmallestRectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2
moments_xldmoments_xldMomentsXldmoments_xldMomentsXldMomentsXld,
smallest_circle_xldsmallest_circle_xldSmallestCircleXldsmallest_circle_xldSmallestCircleXldSmallestCircleXld,
smallest_rectangle1_xldsmallest_rectangle1_xldSmallestRectangle1Xldsmallest_rectangle1_xldSmallestRectangle1XldSmallestRectangle1Xld,
smallest_rectangle2_xldsmallest_rectangle2_xldSmallestRectangle2Xldsmallest_rectangle2_xldSmallestRectangle2XldSmallestRectangle2Xld,
shape_trans_xldshape_trans_xldShapeTransXldshape_trans_xldShapeTransXldShapeTransXld
R. Haralick, L. Shapiro
“Computer and Robot Vision”
Addison-Wesley, 1992, pp. 73-75
Foundation