F_VN_HomographyExp

F_VN_HomographyExp 1:

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

F_VN_HomographyExp 2: 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.)

F_VN_HomographyExp 3: In/Outputs

Name

Type

Description

aPerspectiveTransform

TcVnMatrix3x3_LREAL

Returns the perspective transformation matrix, which transforms the source points to the destination points

F_VN_HomographyExp 4: Return value

HRESULT

Required License

TC3 Vision Base

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