HALCON Reference Manual 10.0.2
Table of Contents / Tools / Hough ClassesClassesClasses | | | Operators

hough_linesT_hough_lineshough_linesHoughLinesHoughLines (Operator)

Name

hough_linesT_hough_lineshough_linesHoughLinesHoughLines — Detect lines in edge images with the help of the Hough transform and returns it in HNF.

Signature

hough_lines(RegionIn : : AngleResolution, Threshold, AngleGap, DistGap : Angle, Dist)

Herror T_hough_lines(const Hobject RegionIn, const Htuple AngleResolution, const Htuple Threshold, const Htuple AngleGap, const Htuple DistGap, Htuple* Angle, Htuple* Dist)

Herror hough_lines(Hobject RegionIn, const HTuple& AngleResolution, const HTuple& Threshold, const HTuple& AngleGap, const HTuple& DistGap, HTuple* Angle, HTuple* Dist)

HTuple HRegion::HoughLines(const HTuple& AngleResolution, const HTuple& Threshold, const HTuple& AngleGap, const HTuple& DistGap, HTuple* Dist) const

void HOperatorSetX.HoughLines(
[in] IHUntypedObjectX* RegionIn, [in] VARIANT AngleResolution, [in] VARIANT Threshold, [in] VARIANT AngleGap, [in] VARIANT DistGap, [out] VARIANT* Angle, [out] VARIANT* Dist)

VARIANT HRegionX.HoughLines(
[in] Hlong AngleResolution, [in] Hlong Threshold, [in] Hlong AngleGap, [in] Hlong DistGap, [out] VARIANT* Dist)

static void HOperatorSet.HoughLines(HObject regionIn, HTuple angleResolution, HTuple threshold, HTuple angleGap, HTuple distGap, out HTuple angle, out HTuple dist)

HTuple HRegion.HoughLines(int angleResolution, int threshold, int angleGap, int distGap, out HTuple dist)

Description

The operator hough_lineshough_lineshough_linesHoughLinesHoughLines allows the selection of linelike structures in a region, whereby it is not necessary that the individual points of a line are connected. This process is based on the Hough transform. The lines are returned in HNF, that is by the direction and length of their normal vector.

The parameter AngleResolutionAngleResolutionAngleResolutionAngleResolutionangleResolution defines the degree of exactness concerning the determination of the angles. It amounts to 1 / AngleResolutionAngleResolutionAngleResolutionAngleResolutionangleResolution degree. The parameter ThresholdThresholdThresholdThresholdthreshold determines by how many points of the original region a line's hypothesis has to be supported at least in order to be taken over into the output. The parameters AngleGapAngleGapAngleGapAngleGapangleGap and DistGapDistGapDistGapDistGapdistGap define a neighborhood of the points in the Hough image in order to determine the local maxima. The lines are returned in HNF.

Parallelization

Parameters

RegionInRegionInRegionInRegionInregionIn (input_object)  region → objectHRegionHRegionHRegionXHobject

Binary edge image in which the lines are to be detected.

AngleResolutionAngleResolutionAngleResolutionAngleResolutionangleResolution (input_control)  integer → HTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong)

Adjusting the resolution in the angle area.

Default value: 4

List of values: 1, 2, 4, 8

ThresholdThresholdThresholdThresholdthreshold (input_control)  integer → HTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong)

Threshold value in the Hough image.

Default value: 100

Typical range of values: 2 ≤ Threshold Threshold Threshold Threshold threshold

AngleGapAngleGapAngleGapAngleGapangleGap (input_control)  integer → HTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong)

Minimal distance of two maxima in the Hough image (direction: angle).

Default value: 5

Typical range of values: 0 ≤ AngleGap AngleGap AngleGap AngleGap angleGap

DistGapDistGapDistGapDistGapdistGap (input_control)  integer → HTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong)

Minimal distance of two maxima in the Hough image (direction: distance).

Default value: 5

Typical range of values: 0 ≤ DistGap DistGap DistGap DistGap distGap

AngleAngleAngleAngleangle (output_control)  hesseline.angle.rad-array → HTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double)

Angles (in radians) of the detected lines' normal vectors.

Typical range of values: -1.5707963 ≤ Angle Angle Angle Angle angle ≤ 3.1415927

DistDistDistDistdist (output_control)  hesseline.distance-array → HTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double)

Distance of the detected lines from the origin.

Number of elements: Dist == Angle

Typical range of values: 0 ≤ Dist Dist Dist Dist dist

Result

The operator hough_lineshough_lineshough_linesHoughLinesHoughLines returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input regions available) is set via the operator set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>), the behavior in case of empty region is set via set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

thresholdthresholdthresholdThresholdThreshold, skeletonskeletonskeletonSkeletonSkeleton

Possible Successors

select_matching_linesselect_matching_linesselect_matching_linesSelectMatchingLinesSelectMatchingLines

See also

hough_line_transhough_line_transhough_line_transHoughLineTransHoughLineTrans, gen_region_hlinegen_region_hlinegen_region_hlineGenRegionHlineGenRegionHline, hough_circleshough_circleshough_circlesHoughCirclesHoughCircles

Module

Foundation

Table of Contents / Tools / Hough ClassesClassesClasses | | | Operators
HALCON Reference Manual 10.0.2 Copyright © 1996-2011 MVTec Software GmbH