CalibrateCamera (Exp)

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.
Can use available TwinCAT Job Tasks for executing parallel code regions.

Syntax

Definition:

HRESULT CalibrateCamera(
    HRESULT                       hrPrev,
    PVOID                         pSrcImages,
    USHORT                        nSrcArraySize,
    ITcVnContainer*               ipReferencePoints,
    TcVnMatrix3x3_LREAL&          aCameraMatrix,
    TcVnArray8_LREAL&             aDistortionCoefficients,
    TcVnMatrix3x3_LREAL&          aRotationMatrix,
    TcVnVector3_LREAL&            aTranslationVector,
    double&                       fReprojError,
    TcVnParamsBlobDetection&      stBlobDetectionParams,
    TcVnCameraCalibrationOptions& stCalibrationOptions,
    bool                          bSubpixelAccuracy = false,
    ETcVnEdgeDirection            eEdgeDirection = ED_DARK_TO_LIGHT,
    float                         fMinStrength = 50,
    ULONG                         nMaxThickness = 10,
    ULONG                         nSubpixelsIterations = 10,
    ULONG                         nSearchLines = 92,
    float                         fApproxPrecision = 0.001f,
    ETcVnEdgeDetectionAlgorithm   eAlgorithm = EDA_INTERPOLATION,
    ETcVnWorldCoordinateSystem    eWorldSystem = WCS_X_RIGHT_Y_DOWN
)

Parameters

Name	Type	Default	Description
hrPrev	HRESULT		HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)
pSrcImages	PVOID		Pointer to an array of source images, each containing the same calibration pattern (1 channel, USINT elements)
nSrcArraySize	USHORT		pSrcImages array size
ipReferencePoints	ITcVnContainer*		Reference calibration pattern point positions (ContainerType_Vector_TcVnPoint3_REAL)
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	double&		Returns the reprojection error
stBlobDetectionParams	TcVnParamsBlobDetection&		Parameters for the internally used F_VN_DetectBlobs function
stCalibrationOptions	TcVnCameraCalibrationOptions&		Calibration options
bSubpixelAccuracy	bool	false	If true, the pattern points are detected with subpixel accuracy
eEdgeDirection	ETcVnEdgeDirection	ED_DARK_TO_LIGHT	Specification of the edge direction to search for (from center to outside ellipse)
fMinStrength	float	50	Specification of the minimum strength (intensity difference) of the edge to search for
nMaxThickness	ULONG	10	Specification of the maximum thickness of the edge to search for, which means fMinStrength must be reached within nMaxThickness pixels
nSubpixelsIterations	ULONG	10	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	ULONG	92	Specifies the amount of search lines, which are equally distributed in all directions (must be >= 8 and a multiple of 4)
fApproxPrecision	float	0.001f	Specifies the approximation precision for APPROX_ERF and APPROX_GAUSSIAN (0.001 usually is sufficient, unused for INTERPOLATION)
eAlgorithm	ETcVnEdgeDetectionAlgorithm	EDA_INTERPOLATION	Selection of the edge detection algorithm
eWorldSystem	ETcVnWorldCoordinateSystem	WCS_X_RIGHT_Y_DOWN	World coordinate system orientation

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