FindTemplateWalshExp (AngleRange)

Match a template image with every location in the source image (using the Walsh transform) and evaluate the comparison results. Returns a sorted list of possible matches (best match first).
Can use available TwinCAT Job Tasks for executing parallel code regions.
Can return partial results when canceled by Watchdog.

Syntax

Definition:

HRESULT FindTemplateWalsh(
    HRESULT                hrPrev,
    ITcVnImage*            ipSrcImage,
    ITcVnImage*            ipTemplateImage,
    ITcVnContainer*&       ipMatches,
    float                  fMatchThreshold,
    ULONG                  nProjections,
    double                 fStartAngle,
    double                 fStopAngle,
    ULONG                  nAngles,
    ULONG                  eOptions = FTWO_NONE,
    float                  fScaleFactor = 1,
    ETcVnInterpolationType eInterpolationType = IT_BILINEAR,
    ITcVnContainer**       pipMatchValues = nullptr
)

Parameters

Name	Type	Default	Description
hrPrev	HRESULT		HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)
ipSrcImage	ITcVnImage*		Source image (USINT or SINT, 1 or 3 channels)
ipTemplateImage	ITcVnImage*		Template image (same type as ipSrcImage, smaller width and height)
ipMatches	ITcVnContainer*&		Returns the matching positions (container type depends on eOptions; ContainerType_Vector_TcVnRotatedRectangle or ContainerType_Vector_TcVnVector4_REAL, where each element contains the center (x, y), the rotation angle in degrees, and the matching value of ipTemplateImage in ipSrcImage; container elements sorted by relevance (best match first))
fMatchThreshold	float		Threshold to separate relevant from irrelevant matches (0..1, 1.0 would be a perfect match.)
nProjections	ULONG		Number of Walsh projections to be used. The higher nProjections the more details are considered for matching. As the most relevant information is captured by the first Walsh projections, a small number (e.g., 5, 10, 25, or 50) is sufficient for many use cases. Each projection requires additional computation time. Therefore, it is advantageous to choose a low number of Walsh projections as long as the matching requirements are fulfilled. The allowed maximum of nProjections is determined by the width and the height of the template image.
fStartAngle	double		First search angle
fStopAngle	double		Last search angle
nAngles	ULONG		Number of different search angles to be used
eOptions	ULONG	FTWO_NONE	Flags controlling the matching process. (see ETcVnFindTemplateWalshOptions; default: TCVN_FTWO_NONE)
fScaleFactor	float	1	Factor (0..1] to reduce source and template image width and height for better performance (but less accuracy!)
eInterpolationType	ETcVnInterpolationType	IT_BILINEAR	Image resize interpolation type (only used if fScaleFactor != 1, TCVN_IT_BILINEAR recommended for most cases)
pipMatchValues	ITcVnContainer**	nullptr	Optionally returns the matching values (ContainerType_Vector_REAL, same size and sort order as ipMatches. Set to 0 if not required.)

Return value

HRESULT

Required License

TC3 Vision Matching

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4026 or later	PC or CX (x64) with min. PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision