F_VN_MeasureAngleBetweenEdgesExp

Syntax

Definition:

FUNCTION F_VN_MeasureAngleBetweenEdgesExp : HRESULT
VAR_INPUT
    ipSrcImage             : ITcVnImage;
END_VAR
VAR_IN_OUT
    fAngle                 : REAL;
    aInnerPoint            : TcVnPoint2_REAL;
    aOuterPoint1           : TcVnPoint2_REAL;
    aOuterPoint2           : TcVnPoint2_REAL;
END_VAR
VAR_INPUT
    eEdgeDirection         : ETcVnEdgeDirection;
    fMinStrength           : REAL;
    nSearchLines           : UDINT;
    fSearchLineDist        : REAL;
    nMaxThickness          : UDINT;
    bInvertSearchDirection : BOOL;
    nSubpixelsIterations   : UDINT;
    bAngleInDegrees        : BOOL;
    fApproxPrecision       : REAL;
    eAlgorithm             : ETcVnEdgeDetectionAlgorithm;
    ipEdgePoints1          : Reference To  ITcVnContainer;
    ipEdgePoints2          : Reference To  ITcVnContainer;
    hrPrev                 : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipSrcImage	ITcVnImage	Source image (1 channel)
eEdgeDirection	ETcVnEdgeDirection	Specification of the edge direction from aInnerPoint to aOuterPoint1 and aOuterPoint2 to search for
fMinStrength	REAL	Specification of the minimum strength (intensity difference) of the edge to search for
nSearchLines	UDINT	Width of the search window, i.e. the number of search lines (3, 5, 7, ...), centered around the line specified by aInnerPoint and aOuterPoint1, aOuterPoint2
fSearchLineDist	REAL	Distance between the search lines in pixels (> 0)
nMaxThickness	UDINT	Specification of the maximum thickness of the edge to search for, which means fMinStrength must be reached within nMaxThickness pixels
bInvertSearchDirection	BOOL	If true, the search starts from each aOuterPoint in direction of aInnerPoint
nSubpixelsIterations	UDINT	Specifies the number of subpixels (for INTERPOLATION, 10 - 20 usually is sufficient) or maximum number of iterations for optimizing the parameters (for APPROX_ERF and APPROX_GAUSSIAN, 50 - 100 usually is sufficient)
bAngleInDegrees	BOOL	fAngle is in degrees, if true
fApproxPrecision	REAL	Specifies the approximation precision for APPROX_ERF and APPROX_GAUSSIAN (0.001 usually is sufficient, unused for INTERPOLATION)
eAlgorithm	ETcVnEdgeDetectionAlgorithm	Selection of the edge detection algorithm
ipEdgePoints1	Reference To ITcVnContainer	Returns the detected edge points between aInnerPoint and aOuterPoint1 (ContainerType_Vector_TcVnPoint2_REAL)
ipEdgePoints2	Reference To ITcVnContainer	Returns the detected edge points between aInnerPoint and aOuterPoint2 (ContainerType_Vector_TcVnPoint2_REAL)
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
fAngle	REAL	Returns the angle between the detected edges (radians or degrees, depending on bAngleInDegrees)
aInnerPoint	TcVnPoint2_REAL	Position inside the angle to measure, from which to start the edge search process (in the direction of aOuterPoint1 and aOuterPoint2)
aOuterPoint1	TcVnPoint2_REAL	Position where the search process for edge 1 ends
aOuterPoint2	TcVnPoint2_REAL	Position where the search process for edge 2 ends

Return value

HRESULT

Weiterführende Informationen

Die Funktion F_VN_MeasureAngleBetweenEdgesExp ist die Expert-Variante von F_VN_MeasureAngleBetweenEdges.

Parameter

Eingangsbild

Das Eingangsbild ipSrcImage muss ein 1-kanaliges Grauwertbild sein.

Winkel ^{(Rückgabewert)}

Der Parameter fAngle gibt den Winkel zwischen den lokalisierten Kanten zurück.

Abhängig vom Parameter bAngleInDegrees ist der Winkel fAngle in Radiant (FALSE) oder in Grad (TRUE) angegeben.

Parameter zur Kantenlokalisierung

Die restlichen Parameter sind ausführlich im Kapitel Kantenlokalisierung erklärt.

Lokalisierte Punkte ^{(Expert, Rückgabewert)}

Die Container ipEdgePoints1 und ipEdgePoints2 geben die exakten Punkte zurück, die anhand jeder Suchlinie lokalisiert wurden. Falls nicht benötigt, kann anstatt eines Interface Pointers der Wert 0 übergeben werden

Parameter zur Kantenlokalisierung

Die restlichen Parameter sind ausführlich im Kapitel Kantenlokalisierung erklärt.

Anwendung

Das Vermessen eines Winkels mit Expert-Parametern sieht z. B. so aus:

hr := F_VN_MeasureAngleBetweenEdgesExp(
    ipSrcImage             :=   ipImageIn, 
    fAngle                 :=   fAngle
    aInnerPoint            :=   aInnerPoint, 
    aOuterPoint1           :=   aOuterPoint1
    aOuterPoint2           :=   aOuterPoint2, 
    eEdgeDirection         :=   TCVN_ED_LIGHT_TO_DARK,
    fMinStrength           :=   fMinStrength, 
    nSearchLines           :=   nSearchLines, 
    fSearchLineDist        :=   fSearchLineDist,
    nMaxThickness          :=   7, 
    nSubpixelsIterations   :=   100, 
    bAngleInDegrees        :=   TRUE, 
    fApproxPrecision       :=   0.0001, 
    eAlgorithm             :=   TCVN_EDA_APPROX_ERF, 
    ipEdgePoints1          :=   ipEdgePoints1, 
    ipEdgePoints2          :=   ipEdgePoints2, 
    hrPrev                 :=   hr
);

Beispiele

Measure Angle Between Edges

Required License

TC3 Vision Metrology 2D

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1. 4024.44 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision