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measure_posT_measure_posMeasurePosmeasure_posMeasurePosMeasurePos (Operator)

Name

measure_posT_measure_posMeasurePosmeasure_posMeasurePosMeasurePos — Extract straight edges perpendicular to a rectangle or annular arc.

Signature

measure_pos(Image : : MeasureHandle, Sigma, Threshold, Transition, Select : RowEdge, ColumnEdge, Amplitude, Distance)

Herror T_measure_pos(const Hobject Image, const Htuple MeasureHandle, const Htuple Sigma, const Htuple Threshold, const Htuple Transition, const Htuple Select, Htuple* RowEdge, Htuple* ColumnEdge, Htuple* Amplitude, Htuple* Distance)

Herror measure_pos(Hobject Image, const HTuple& MeasureHandle, const HTuple& Sigma, const HTuple& Threshold, const HTuple& Transition, const HTuple& Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance)

HTuple HImage::MeasurePos(const HMeasure& MeasureHandle, const HTuple& Sigma, const HTuple& Threshold, const HTuple& Transition, const HTuple& Select, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

HTuple HMeasure::MeasurePos(const HImage& Image, const HTuple& Sigma, const HTuple& Threshold, const HTuple& Transition, const HTuple& Select, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

void MeasurePos(const HObject& Image, const HTuple& MeasureHandle, const HTuple& Sigma, const HTuple& Threshold, const HTuple& Transition, const HTuple& Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance)

void HMeasure::MeasurePos(const HImage& Image, double Sigma, double Threshold, const HString& Transition, const HString& Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

void HMeasure::MeasurePos(const HImage& Image, double Sigma, double Threshold, const char* Transition, const char* Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

void HImage::MeasurePos(const HMeasure& MeasureHandle, double Sigma, double Threshold, const HString& Transition, const HString& Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

void HImage::MeasurePos(const HMeasure& MeasureHandle, double Sigma, double Threshold, const char* Transition, const char* Select, HTuple* RowEdge, HTuple* ColumnEdge, HTuple* Amplitude, HTuple* Distance) const

void HOperatorSetX.MeasurePos(
[in] IHUntypedObjectX* Image, [in] VARIANT MeasureHandle, [in] VARIANT Sigma, [in] VARIANT Threshold, [in] VARIANT Transition, [in] VARIANT Select, [out] VARIANT* RowEdge, [out] VARIANT* ColumnEdge, [out] VARIANT* Amplitude, [out] VARIANT* Distance)

VARIANT HMeasureX.MeasurePos(
[in] IHImageX* Image, [in] double Sigma, [in] double Threshold, [in] BSTR Transition, [in] BSTR Select, [out] VARIANT* ColumnEdge, [out] VARIANT* Amplitude, [out] VARIANT* Distance)

VARIANT HImageX.MeasurePos(
[in] IHMeasureX* MeasureHandle, [in] double Sigma, [in] double Threshold, [in] BSTR Transition, [in] BSTR Select, [out] VARIANT* ColumnEdge, [out] VARIANT* Amplitude, [out] VARIANT* Distance)

static void HOperatorSet.MeasurePos(HObject image, HTuple measureHandle, HTuple sigma, HTuple threshold, HTuple transition, HTuple select, out HTuple rowEdge, out HTuple columnEdge, out HTuple amplitude, out HTuple distance)

void HMeasure.MeasurePos(HImage image, double sigma, double threshold, string transition, string select, out HTuple rowEdge, out HTuple columnEdge, out HTuple amplitude, out HTuple distance)

void HImage.MeasurePos(HMeasure measureHandle, double sigma, double threshold, string transition, string select, out HTuple rowEdge, out HTuple columnEdge, out HTuple amplitude, out HTuple distance)

Description

measure_posmeasure_posMeasurePosmeasure_posMeasurePosMeasurePos extracts straight edges which lie perpendicular to the major axis of a rectangle or annular arc.

The algorithm works by averaging the gray values in “slices” perpendicular to the major axis of the rectangle or annular arc in order to obtain a one-dimensional edge profile. The sampling is done at subpixel positions in the image ImageImageImageImageImageimage at integer row and column distances (in the coordinate frame of the rectangle) from the center of the rectangle. Since this involves some calculations which can be used repeatedly in several measurements, the operator gen_measure_rectangle2gen_measure_rectangle2GenMeasureRectangle2gen_measure_rectangle2GenMeasureRectangle2GenMeasureRectangle2 or gen_measure_arcgen_measure_arcGenMeasureArcgen_measure_arcGenMeasureArcGenMeasureArc is used to perform these calculations only once, thus increasing the speed of measure_posmeasure_posMeasurePosmeasure_posMeasurePosMeasurePos significantly. Since there is a trade-off between accuracy and speed in the subpixel calculations of the gray values, and thus in the accuracy of the extracted edge positions, different interpolation schemes can be selected in gen_measure_rectangle2gen_measure_rectangle2GenMeasureRectangle2gen_measure_rectangle2GenMeasureRectangle2GenMeasureRectangle2. (The interpolation only influences rectangles not aligned with the image axes.) The measure object generated with gen_measure_rectangle2gen_measure_rectangle2GenMeasureRectangle2gen_measure_rectangle2GenMeasureRectangle2GenMeasureRectangle2 is passed in MeasureHandleMeasureHandleMeasureHandleMeasureHandleMeasureHandlemeasureHandle.

After the one-dimensional edge profile has been calculated, subpixel edge locations are computed by convolving the profile with the derivatives of a Gaussian smoothing kernel of standard deviation SigmaSigmaSigmaSigmaSigmasigma. Salient edges can be selected with the parameter ThresholdThresholdThresholdThresholdThresholdthreshold, which constitutes a threshold on the amplitude, i.e., the absolute value of the first derivative of the edge. Note that the amplitude values are scaled by the factor SigmaSigmaSigmaSigmaSigmasigma*sqrt(2*Pi). Additionally, it is possible to select only positive edges, i.e., edges which constitute a dark-to-light transition in the direction of the major axis of the rectangle or the arc (TransitionTransitionTransitionTransitionTransitiontransition = 'positive'"positive""positive""positive""positive""positive"), only negative edges, i.e., light-to-dark transitions (TransitionTransitionTransitionTransitionTransitiontransition = 'negative'"negative""negative""negative""negative""negative"), or both types of edges (TransitionTransitionTransitionTransitionTransitiontransition = 'all'"all""all""all""all""all"). Finally, it is possible to select which edge points are returned. If SelectSelectSelectSelectSelectselect is set to 'all'"all""all""all""all""all", all edge points are returned. If it is set to 'first'"first""first""first""first""first", only the first of the extracted edge points is returned, while it is set to 'last'"last""last""last""last""last", only the last one is returned.

The extracted edges are returned as single points which lie on the major axis of the rectangle or arc in (RowEdgeRowEdgeRowEdgeRowEdgeRowEdgerowEdge,ColumnEdgeColumnEdgeColumnEdgeColumnEdgeColumnEdgecolumnEdge). The corresponding edge amplitudes are returned in AmplitudeAmplitudeAmplitudeAmplitudeAmplitudeamplitude. In addition, the distance between consecutive edge points is returned in DistanceDistanceDistanceDistanceDistancedistance. Here, Distance[i] corresponds to the distance between Edge[i] and Edge[i+1], i.e., the tuple DistanceDistanceDistanceDistanceDistancedistance contains one element less than the tuples RowEdgeRowEdgeRowEdgeRowEdgeRowEdgerowEdge and ColumnEdgeColumnEdgeColumnEdgeColumnEdgeColumnEdgecolumnEdge.

Attention

measure_posmeasure_posMeasurePosmeasure_posMeasurePosMeasurePos only returns meaningful results if the assumptions that the edges are straight and perpendicular to the major axis of the rectangle or arc are fulfilled. Thus, it should not be used to extract edges from curved objects, for example. Furthermore, the user should ensure that the rectangle or arc is as close to perpendicular as possible to the edges in the image. Additionally, SigmaSigmaSigmaSigmaSigmasigma must not become larger than approx. 0.5 * Length1 (for Length1 see gen_measure_rectangle2gen_measure_rectangle2GenMeasureRectangle2gen_measure_rectangle2GenMeasureRectangle2GenMeasureRectangle2).

It should be kept in mind that measure_posmeasure_posMeasurePosmeasure_posMeasurePosMeasurePos ignores the domain of ImageImageImageImageImageimage for efficiency reasons. If certain regions in the image should be excluded from the measurement a new measure object with appropriately modified parameters should be generated.

Parallelization

Parameters

ImageImageImageImageImageimage (input_object)  singlechannelimage → objectHImageHImageHImageHImageXHobject (byte / uint2 / real)

Input image.

MeasureHandleMeasureHandleMeasureHandleMeasureHandleMeasureHandlemeasureHandle (input_control)  measure_id → HMeasure, HTupleHTupleHMeasure, HTupleHMeasureX, VARIANTHtuple (integer) (IntPtr) (Hlong) (Hlong) (Hlong) (Hlong)

Measure object handle.

SigmaSigmaSigmaSigmaSigmasigma (input_control)  number → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Sigma of gaussian smoothing.

Default value: 1.0

Suggested values: 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 7.0, 10.0

Typical range of values: 0.4 ≤ Sigma Sigma Sigma Sigma Sigma sigma ≤ 100 (lin)

Minimum increment: 0.01

Recommended increment: 0.1

Restriction: Sigma >= 0.4

ThresholdThresholdThresholdThresholdThresholdthreshold (input_control)  number → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Minimum edge amplitude.

Default value: 30.0

Suggested values: 5.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 90.0, 110.0

Typical range of values: 1 ≤ Threshold Threshold Threshold Threshold Threshold threshold ≤ 255 (lin)

Minimum increment: 0.5

Recommended increment: 2

TransitionTransitionTransitionTransitionTransitiontransition (input_control)  string → HTupleHTupleHTupleVARIANTHtuple (string) (string) (HString) (char*) (BSTR) (char*)

Light/dark or dark/light edge.

Default value: 'all' "all" "all" "all" "all" "all"

List of values: 'all'"all""all""all""all""all", 'negative'"negative""negative""negative""negative""negative", 'positive'"positive""positive""positive""positive""positive"

SelectSelectSelectSelectSelectselect (input_control)  string → HTupleHTupleHTupleVARIANTHtuple (string) (string) (HString) (char*) (BSTR) (char*)

Selection of end points.

Default value: 'all' "all" "all" "all" "all" "all"

List of values: 'all'"all""all""all""all""all", 'first'"first""first""first""first""first", 'last'"last""last""last""last""last"

RowEdgeRowEdgeRowEdgeRowEdgeRowEdgerowEdge (output_control)  point.y-array → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Row coordinate of the center of the edge.

ColumnEdgeColumnEdgeColumnEdgeColumnEdgeColumnEdgecolumnEdge (output_control)  point.x-array → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Column coordinate of the center of the edge.

AmplitudeAmplitudeAmplitudeAmplitudeAmplitudeamplitude (output_control)  real-array → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Edge amplitude of the edge (with sign).

DistanceDistanceDistanceDistanceDistancedistance (output_control)  real-array → HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Distance between consecutive edges.

Result

If the parameter values are correct the operator measure_posmeasure_posMeasurePosmeasure_posMeasurePosMeasurePos returns the value 2 (H_MSG_TRUE). Otherwise an exception is raised.

Possible Predecessors

gen_measure_rectangle2gen_measure_rectangle2GenMeasureRectangle2gen_measure_rectangle2GenMeasureRectangle2GenMeasureRectangle2

Possible Successors

close_measureclose_measureCloseMeasureclose_measureCloseMeasureCloseMeasure

Alternatives

edges_sub_pixedges_sub_pixEdgesSubPixedges_sub_pixEdgesSubPixEdgesSubPix, fuzzy_measure_posfuzzy_measure_posFuzzyMeasurePosfuzzy_measure_posFuzzyMeasurePosFuzzyMeasurePos

See also

measure_pairsmeasure_pairsMeasurePairsmeasure_pairsMeasurePairsMeasurePairs, fuzzy_measure_pairsfuzzy_measure_pairsFuzzyMeasurePairsfuzzy_measure_pairsFuzzyMeasurePairsFuzzyMeasurePairs, fuzzy_measure_pairingfuzzy_measure_pairingFuzzyMeasurePairingfuzzy_measure_pairingFuzzyMeasurePairingFuzzyMeasurePairing

Module

1D Metrology

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HALCON Operator Reference 11.0.5 Copyright © 1996-2015 MVTec Software GmbH