F_VN_CalibrateCameraExp3

Compute the camera parameters (intrinsic + extrinsic) by evaluating images containing a calibration pattern (circles). The extrinsic parameters are computed for the first image in the array. (expert function)
Can use available TwinCAT Job Tasks for executing parallel code regions.

Syntax

Definition:

FUNCTION F_VN_CalibrateCameraExp3 : HRESULT
VAR_INPUT
    pSrcImages              : PVOID;
    nSrcArraySize           : UINT;
    ipReferencePoints       : ITcVnContainer;
END_VAR
VAR_IN_OUT
    aCameraMatrix           : TcVnMatrix3x3_LREAL;
    aDistortionCoefficients : TcVnArray8_LREAL;
    aRotationMatrix         : TcVnMatrix3x3_LREAL;
    aTranslationVector      : TcVnVector3_LREAL;
    fReprojError            : LREAL;
    stBlobDetectionParams   : TcVnParamsBlobDetection;
    stCalibrationOptions    : TcVnCameraCalibrationOptions;
END_VAR
VAR_INPUT
    bSubpixelAccuracy       : BOOL;
    eEdgeDirection          : ETcVnEdgeDirection;
    fMinStrength            : REAL;
    nMaxThickness           : UDINT;
    nSubpixelsIterations    : UDINT;
    nSearchLines            : UDINT;
    fApproxPrecision        : REAL;
    eAlgorithm              : ETcVnEdgeDetectionAlgorithm;
    eWorldSystem            : ETcVnWorldCoordinateSystem;
    hrPrev                  : HRESULT;
END_VAR

Inputs

Name	Type	Description
pSrcImages	PVOID	Pointer to an array of source images, each containing the same calibration pattern (1 channel, USINT elements)
nSrcArraySize	UINT	pSrcImages array size
ipReferencePoints	ITcVnContainer	Reference calibration pattern point positions (ContainerType_Vector_TcVnPoint3_REAL)
bSubpixelAccuracy	BOOL	If true, the pattern points are detected with subpixel accuracy
eEdgeDirection	ETcVnEdgeDirection	Specification of the edge direction to search for (from center to outside ellipse)
fMinStrength	REAL	Specification of the minimum strength (intensity difference) of the edge to search for
nMaxThickness	UDINT	Specification of the maximum thickness of the edge to search for, which means fMinStrength must be reached within nMaxThickness pixels
nSubpixelsIterations	UDINT	Specifies the number of subpixels (for INTERPOLATION, 10 - 20 usually is sufficient) or maximum number of iterations for optimizing the parameters (for APPROX_ERF and APPROX_GAUSSIAN, 50 - 100 usually is sufficient)
nSearchLines	UDINT	Specifies the amount of search lines, which are equally distributed in all directions (must be >= 8 and a multiple of 4)
fApproxPrecision	REAL	Specifies the approximation precision for APPROX_ERF and APPROX_GAUSSIAN (0.001 usually is sufficient, unused for INTERPOLATION)
eAlgorithm	ETcVnEdgeDetectionAlgorithm	Selection of the edge detection algorithm
eWorldSystem	ETcVnWorldCoordinateSystem	World coordinate system orientation
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
aCameraMatrix	TcVnMatrix3x3_LREAL	Returns the camera matrix
aDistortionCoefficients	TcVnArray8_LREAL	Returns the lens distortion coefficients [k1, k2, p1, p2, k3, k4, k5, k6]
aRotationMatrix	TcVnMatrix3x3_LREAL	Returns the rotation matrix
aTranslationVector	TcVnVector3_LREAL	Returns the translation vector
fReprojError	LREAL	Returns the reprojection error
stBlobDetectionParams	TcVnParamsBlobDetection	Parameters for the internally used F_VN_DetectBlobs function
stCalibrationOptions	TcVnCameraCalibrationOptions	Calibration options

Return value

HRESULT

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