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 |
Source image (1 channel) | |
|
eEdgeDirection |
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 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 |
Position inside the angle to measure, from which to start the edge search process (in the direction of aOuterPoint1 and aOuterPoint2) | |
|
aOuterPoint1 |
Position where the search process for edge 1 ends | |
|
aOuterPoint2 |
Position where the search process for edge 2 ends |
Return valueFurther information
The function F_VN_MeasureAngleBetweenEdges localizes two linear edges and measures the angle between them.
Parameter
Input image
The input image ipSrcImage must be a 1-channel grayscale image.
Angle (Return value)
The parameter fAngle returns the angle between the localized edges.
Depending on the parameter bAngleInDegrees, the angle fAngle is specified in radians (FALSE) or in degrees (TRUE).
Parameters for edge localization
The remaining parameters are explained in detail in the chapter Edge localization.
Expert parameters
The expert version F_VN_MeasureAngleBetweenEdgesExp contains additional parameters.
Application
The measurement of an angle between two linear edges looks like this, for example:
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
);
Samples
Required License
TC3 Vision Metrology 2D
System Requirements
Development environment | Target platform | PLC libraries to include |
|---|---|---|
TwinCAT V3.1.4024.54 or later | PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU | Tc3_Vision |