Operator Reference

HALCON Operator Reference / XLD / Features
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dist_ellipse_contour_xlddist_ellipse_contour_xldDistEllipseContourXldDistEllipseContourXlddist_ellipse_contour_xld (Operator)

dist_ellipse_contour_xlddist_ellipse_contour_xldDistEllipseContourXldDistEllipseContourXlddist_ellipse_contour_xld — Compute the distance of contours to an ellipse.

Signature

Herror dist_ellipse_contour_xld(const Hobject Contours, const char* Mode, const Hlong MaxNumPoints, const Hlong ClippingEndPoints, double Row, double Column, double Phi, double Radius1, double Radius2, double* MinDist, double* MaxDist, double* AvgDist, double* SigmaDist)

Herror T_dist_ellipse_contour_xld(const Hobject Contours, const Htuple Mode, const Htuple MaxNumPoints, const Htuple ClippingEndPoints, const Htuple Row, const Htuple Column, const Htuple Phi, const Htuple Radius1, const Htuple Radius2, Htuple* MinDist, Htuple* MaxDist, Htuple* AvgDist, Htuple* SigmaDist)

void DistEllipseContourXld(const HObject& Contours, const HTuple& Mode, const HTuple& MaxNumPoints, const HTuple& ClippingEndPoints, const HTuple& Row, const HTuple& Column, const HTuple& Phi, const HTuple& Radius1, const HTuple& Radius2, HTuple* MinDist, HTuple* MaxDist, HTuple* AvgDist, HTuple* SigmaDist)

void HXLDCont::DistEllipseContourXld(const HString& Mode, Hlong MaxNumPoints, Hlong ClippingEndPoints, double Row, double Column, double Phi, double Radius1, double Radius2, HTuple* MinDist, HTuple* MaxDist, HTuple* AvgDist, HTuple* SigmaDist) const

void HXLDCont::DistEllipseContourXld(const HString& Mode, Hlong MaxNumPoints, Hlong ClippingEndPoints, double Row, double Column, double Phi, double Radius1, double Radius2, double* MinDist, double* MaxDist, double* AvgDist, double* SigmaDist) const

void HXLDCont::DistEllipseContourXld(const char* Mode, Hlong MaxNumPoints, Hlong ClippingEndPoints, double Row, double Column, double Phi, double Radius1, double Radius2, double* MinDist, double* MaxDist, double* AvgDist, double* SigmaDist) const

void HXLDCont::DistEllipseContourXld(const wchar_t* Mode, Hlong MaxNumPoints, Hlong ClippingEndPoints, double Row, double Column, double Phi, double Radius1, double Radius2, double* MinDist, double* MaxDist, double* AvgDist, double* SigmaDist) const   ( Windows only)

static void HOperatorSet.DistEllipseContourXld(HObject contours, HTuple mode, HTuple maxNumPoints, HTuple clippingEndPoints, HTuple row, HTuple column, HTuple phi, HTuple radius1, HTuple radius2, out HTuple minDist, out HTuple maxDist, out HTuple avgDist, out HTuple sigmaDist)

void HXLDCont.DistEllipseContourXld(string mode, int maxNumPoints, int clippingEndPoints, double row, double column, double phi, double radius1, double radius2, out HTuple minDist, out HTuple maxDist, out HTuple avgDist, out HTuple sigmaDist)

void HXLDCont.DistEllipseContourXld(string mode, int maxNumPoints, int clippingEndPoints, double row, double column, double phi, double radius1, double radius2, out double minDist, out double maxDist, out double avgDist, out double sigmaDist)

def dist_ellipse_contour_xld(contours: HObject, mode: str, max_num_points: int, clipping_end_points: int, row: float, column: float, phi: float, radius_1: float, radius_2: float) -> Tuple[Sequence[float], Sequence[float], Sequence[float], Sequence[float]]

def dist_ellipse_contour_xld_s(contours: HObject, mode: str, max_num_points: int, clipping_end_points: int, row: float, column: float, phi: float, radius_1: float, radius_2: float) -> Tuple[float, float, float, float]

Description

dist_ellipse_contour_xlddist_ellipse_contour_xldDistEllipseContourXldDistEllipseContourXlddist_ellipse_contour_xld determines the distance between the contours in ContoursContoursContourscontourscontours and an ellipse specified by the center (RowRowRowrowrow, ColumnColumnColumncolumncolumn), the orientation of the main axis PhiPhiPhiphiphi, the length of the larger half axis Radius1Radius1Radius1radius1radius_1, and the length of the smaller half axis Radius2Radius2Radius2radius2radius_2. Different measures for the distance of a contour point to the ellipse are available (ModeModeModemodemode):

'geometric'"geometric""geometric""geometric""geometric"

The underlying distance measure is the geometric distance between a point on the contour and the ellipse. This measure is also called orthogonal or Euclidean distance.

'algebraic'"algebraic""algebraic""algebraic""algebraic"

The distance is measured by the algebraic distance , where the parameters a - f describing the ellipse are normalized in order to obtain Radius2Radius2Radius2radius2radius_2 as distance of the center of the ellipse. This measure shows a high curvature bias: Near points of high curvature on the ellipse (like the poles on the main axis) the distance is smaller than near points with low curvature.

'focpoints'"focpoints""focpoints""focpoints""focpoints"

The distance is measured by the deviation , where are the focal points and a corresponds to Radius1Radius1Radius1radius1radius_1. This measure shows a low curvature bias: Near points of high curvature on the ellipse (like the poles on the main axis) the distance is larger than near points with low curvature.

'bisec'"bisec""bisec""bisec""bisec"

The distance is measured by the distance between X and the intersection of the angular bisector of the two lines through X and the focal points with the ellipse. This is a good approximation of the orthogonal distance from X to the ellipse. The accuracy of the approximation depends on both the aspect ratio of the ellipse and the distance.

The operator returns the minimum absolute distance MinDistMinDistMinDistminDistmin_dist, the maximum absolute distance MaxDistMaxDistMaxDistmaxDistmax_dist, the average absolute distance AvgDistAvgDistAvgDistavgDistavg_dist, and the standard deviation of the absolute distances SigmaDistSigmaDistSigmaDistsigmaDistsigma_dist of all contour points.

To reduce the computational load, the computation of the distances can be restricted to a subset of the contour points: If a value other than -1 is assigned to MaxNumPointsMaxNumPointsMaxNumPointsmaxNumPointsmax_num_points, only up to MaxNumPointsMaxNumPointsMaxNumPointsmaxNumPointsmax_num_points points - uniformly distributed over the contour - are used. Due to artifacts in the pre-processing the start and end points of a contour might be faulty. Therefore, it is possible to exclude ClippingEndPointsClippingEndPointsClippingEndPointsclippingEndPointsclipping_end_points points at the beginning and at the end of a contour from the computation.

Execution Information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).
  • Multithreading scope: global (may be called from any thread).
  • Processed without parallelization.

Parameters

ContoursContoursContourscontourscontours (input_object)  xld_cont(-array) → objectHXLDContHObjectHObjectHobject

Input contours.

ModeModeModemodemode (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Method for the determination of the distances.

Default: 'geometric' "geometric" "geometric" "geometric" "geometric"

List of values: 'algebraic'"algebraic""algebraic""algebraic""algebraic", 'bisec'"bisec""bisec""bisec""bisec", 'focpoints'"focpoints""focpoints""focpoints""focpoints", 'geometric'"geometric""geometric""geometric""geometric"

MaxNumPointsMaxNumPointsMaxNumPointsmaxNumPointsmax_num_points (input_control)  integer → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Maximum number of contour points used for the computation (-1 for all points).

Default: -1

Restriction: MaxNumPoints >= 3

ClippingEndPointsClippingEndPointsClippingEndPointsclippingEndPointsclipping_end_points (input_control)  integer → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Number of points at the beginning and the end of the contours to be ignored for the computation of distances.

Default: 0

Restriction: ClippingEndPoints >= 0

RowRowRowrowrow (input_control)  ellipse.center.y → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Row coordinate of the center of the ellipse.

ColumnColumnColumncolumncolumn (input_control)  ellipse.center.x → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Column coordinate of the center of the ellipse.

PhiPhiPhiphiphi (input_control)  ellipse.angle.rad → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Orientation of the main axis in radian.

Restriction: Phi >= 0 && Phi <= 6.283185307

Radius1Radius1Radius1radius1radius_1 (input_control)  ellipse.radius1 → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Length of the larger half axis.

Restriction: Radius1 > 0

Radius2Radius2Radius2radius2radius_2 (input_control)  ellipse.radius2 → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Length of the smaller half axis.

Restriction: Radius2 >= 0 && Radius2 <= Radius1

MinDistMinDistMinDistminDistmin_dist (output_control)  real(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)

Minimum distance.

MaxDistMaxDistMaxDistmaxDistmax_dist (output_control)  real(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)

Maximum distance.

AvgDistAvgDistAvgDistavgDistavg_dist (output_control)  real(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)

Mean distance.

SigmaDistSigmaDistSigmaDistsigmaDistsigma_dist (output_control)  real(-array) → HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)

Standard deviation of the distance.

Example (HDevelop)

read_image (Image, 'caltab')
find_caltab (Image, CalPlate, 'caltab_big.descr', 3, 112, 5)
reduce_domain (Image, CalPlate, ImageReduced)
edges_sub_pix (ImageReduced, Edges, 'lanser2', 0.5, 20, 40)
select_contours_xld (Edges, EdgesClosed, 'closed', 0, 2.0, 0, 0)
select_contours_xld (EdgesClosed, EdgesMarks, 'contour_length', 20, 100, \
                     0, 0)
fit_ellipse_contour_xld (EdgesMarks, 'fitzgibbon', -1, 2, 0, 200, 3, 2.0, \
                         Row, Column, Phi, Radius1, Radius2, StartPhi, \
                         EndPhi, PointOrder)
for i := 0 to |Row|-1 by 1
    select_obj (EdgesMarks, ObjectSelected, i+1)
    dist_ellipse_contour_xld (ObjectSelected, 'bisec', -1, 0, Row[i], \
                              Column[i], Phi[i], Radius1[i], Radius2[i], \
                              MinDist, MaxDist, AvgDist, SigmaDist)
endfor

Example (HDevelop)

read_image (Image, 'caltab')
find_caltab (Image, CalPlate, 'caltab_big.descr', 3, 112, 5)
reduce_domain (Image, CalPlate, ImageReduced)
edges_sub_pix (ImageReduced, Edges, 'lanser2', 0.5, 20, 40)
select_contours_xld (Edges, EdgesClosed, 'closed', 0, 2.0, 0, 0)
select_contours_xld (EdgesClosed, EdgesMarks, 'contour_length', 20, 100, \
                     0, 0)
fit_ellipse_contour_xld (EdgesMarks, 'fitzgibbon', -1, 2, 0, 200, 3, 2.0, \
                         Row, Column, Phi, Radius1, Radius2, StartPhi, \
                         EndPhi, PointOrder)
for i := 0 to |Row|-1 by 1
    select_obj (EdgesMarks, ObjectSelected, i+1)
    dist_ellipse_contour_xld (ObjectSelected, 'bisec', -1, 0, Row[i], \
                              Column[i], Phi[i], Radius1[i], Radius2[i], \
                              MinDist, MaxDist, AvgDist, SigmaDist)
endfor

Example (C++)

read_image (Image, "caltab");
find_caltab (Image, &CalPlate, "caltab_big.descr", 3, 112, 5)
reduce_domain (Image, CalPlate, &ImageReduced);
edges_sub_pix (ImageReduced, &Edges, "lanser2", 0.5, 20, 40);
select_contours_xld (Edges, &EdgesClosed, "closed", 0, 2.0, 0, 0);
select_contours_xld (EdgesClosed, &EdgesMarks, "contour_length", 20, 100,
                     0, 0);
fit_ellipse_contour_xld (EdgesMarks, "fitzgibbon", -1, 2, 0, 200, 3, 2.0,
                         &Row, &Column, &Phi, &Radius1, &Radius2,
                         &StartPhi, &EndPhi, &PointOrder);
for (i=0; i<Row.Num(); i++)
{
  select_obj (EdgesMarks, &ObjectSelected, i+1);
  dist_ellipse_contour_xld (ObjectSelected, "bisec", -1, 0, Row[i],
                            Column[i], Phi[i], Radius1[i], Radius2[i],
                            &MinDist, &MaxDist, &AvgDist, &SigmaDist);
}

Example (HDevelop)

read_image (Image, 'caltab')
find_caltab (Image, CalPlate, 'caltab_big.descr', 3, 112, 5)
reduce_domain (Image, CalPlate, ImageReduced)
edges_sub_pix (ImageReduced, Edges, 'lanser2', 0.5, 20, 40)
select_contours_xld (Edges, EdgesClosed, 'closed', 0, 2.0, 0, 0)
select_contours_xld (EdgesClosed, EdgesMarks, 'contour_length', 20, 100, \
                     0, 0)
fit_ellipse_contour_xld (EdgesMarks, 'fitzgibbon', -1, 2, 0, 200, 3, 2.0, \
                         Row, Column, Phi, Radius1, Radius2, StartPhi, \
                         EndPhi, PointOrder)
for i := 0 to |Row|-1 by 1
    select_obj (EdgesMarks, ObjectSelected, i+1)
    dist_ellipse_contour_xld (ObjectSelected, 'bisec', -1, 0, Row[i], \
                              Column[i], Phi[i], Radius1[i], Radius2[i], \
                              MinDist, MaxDist, AvgDist, SigmaDist)
endfor

Result

dist_ellipse_contour_xlddist_ellipse_contour_xldDistEllipseContourXldDistEllipseContourXlddist_ellipse_contour_xld returns 2 ( H_MSG_TRUE) if all parameter values are correct. If necessary, an exception is raised.

Possible Predecessors

fit_ellipse_contour_xldfit_ellipse_contour_xldFitEllipseContourXldFitEllipseContourXldfit_ellipse_contour_xld

Alternatives

dist_ellipse_contour_points_xlddist_ellipse_contour_points_xldDistEllipseContourPointsXldDistEllipseContourPointsXlddist_ellipse_contour_points_xld

Module

Foundation

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