F_VN_HomographyExp

Find the homography (perspective transformation) between two planar point sets. (expert function)

Syntax

Definition:

FUNCTION F_VN_HomographyExp : HRESULT
VAR_INPUT
    ipSrcPoints           : ITcVnContainer;
    ipDestPoints          : ITcVnContainer;
END_VAR
VAR_IN_OUT
    aPerspectiveTransform : TcVnMatrix3x3_LREAL;
END_VAR
VAR_INPUT
    eAlgorithm            : ETcVnEstimationAlgorithm;
    fReprojThreshold      : LREAL;
    ipInlierMask          : Reference To  ITcVnContainer;
    nMaxIterations        : UDINT;
    fConfidence           : LREAL;
    hrPrev                : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipSrcPoints	ITcVnContainer	Container with at least 4 source points (ContainerType_Vector_TcVnPoint2_REAL)
ipDestPoints	ITcVnContainer	Container with destination points (same number as ipSrcPoints, ContainerType_Vector_TcVnPoint2_REAL)
eAlgorithm	ETcVnEstimationAlgorithm	Estimation algorithm
fReprojThreshold	LREAL	Maximum allowed reprojection error to treat a point pair as an inlier (only for RANSAC, RHO)
ipInlierMask	Reference To ITcVnContainer	Returns a mask marking the inliers (optional, set to 0 if not required; ContainerType_Vector_SINT; only for RANSAC, LMEDS)
nMaxIterations	UDINT	Maximum number of RANSAC iterations
fConfidence	LREAL	Confidence (0..1)
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
aPerspectiveTransform	TcVnMatrix3x3_LREAL	Returns the perspective transformation matrix, which transforms the source points to the destination points

Return value

HRESULT

Required License

TC3 Vision Base

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