F_VN_DecomposeHomography

Decompose a homography matrix into four solutions of rotation, translation, and plane normal. It returns two solutions (Ra, Ta, Nb) and (Rb, Tb, Nb). The third and the fourth solutions can be calculated as follows: (Ra, -Ta, -Na) and (Rb, -Tb, -Nb).

Syntax

Definition:

FUNCTION F_VN_DecomposeHomography : HRESULT
VAR_IN_OUT
    aHomography         : TcVnMatrix3x3_LREAL;
    aCameraMatrix       : TcVnMatrix3x3_LREAL;
    aRotationMatrixA    : TcVnMatrix3x3_LREAL;
    aTranslationVectorA : TcVnVector3_LREAL;
    aNormVectorA        : TcVnVector3_LREAL;
    aRotationMatrixB    : TcVnMatrix3x3_LREAL;
    aTranslationVectorB : TcVnVector3_LREAL;
    aNormVectorB        : TcVnVector3_LREAL;
END_VAR
VAR_INPUT
    hrPrev              : HRESULT;
END_VAR
VAR_OUTPUT
    nSolutions          : UDINT;
END_VAR

Inputs

Name	Type	Description
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
aHomography	TcVnMatrix3x3_LREAL	Homography matrix (a perspective transformation between two planes)
aCameraMatrix	TcVnMatrix3x3_LREAL	Camera matrix
aRotationMatrixA	TcVnMatrix3x3_LREAL	Rotation matrix of the first solution (Ra)
aTranslationVectorA	TcVnVector3_LREAL	Translation vector of the first solution (Ta)
aNormVectorA	TcVnVector3_LREAL	Norm vector of the first solution (Na)
aRotationMatrixB	TcVnMatrix3x3_LREAL	Rotation matrix of the second solution (Rb)
aTranslationVectorB	TcVnVector3_LREAL	Translation vector of the second solution (Tb)
aNormVectorB	TcVnVector3_LREAL	Norm vector of the second solution Nb

Outputs

Name	Type	Description
nSolutions	UDINT	Returns the number of solutions. In normal cases, it is equal four.

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