F_VN_MeasureAngleBetweenEdges

Measure the angle between 2 edges, using an interpolation method.
Can use available TwinCAT Job Tasks for executing parallel code regions.
Can return partial results when canceled by Watchdog.

Syntax

Definition:

FUNCTION F_VN_MeasureAngleBetweenEdges : 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;
    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 windows, i.e. the number of search lines (3, 5, 7, ...), centered around the lines specified by aInnerPoint and aOuterPoint1, aOuterPoint2
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)
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_MeasureAngleBetweenEdges lokalisiert zwei lineare Kanten und misst den Winkel zwischen ihnen.

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.

Expert-Parameter

Die Expert-Variante F_VN_MeasureAngleBetweenEdgesExp enthält zusätzliche Parameter.

Anwendung

Das Vermessen eines Winkels zwischen zwei linearen Kanten 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, 
    hrPrev                 :=   hr
);

Beispiele

Measure Angle Between Edges

Required License

TC3 Vision Metrology 2D

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.59 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision