imaqFindTransformRect2

Usage

int imaqFindTransformRect2(Image* image, const ROI* roi, FindTransformMode mode, CoordinateSystem* baseSystem, CoordinateSystem* newSystem, const FindTransformRectOptions2* findTransformOptions, const StraightEdgeOptions* straightEdgeOptions, AxisReport* axisReport);

Purpose

Computes a coordinate transform based on the position of an object in a search area of an image. The function uses the location and orientation of the coordinate system it finds to create the reference system of a coordinate transform or to update the measurement system of an existing coordinate transform. imaqFindTransformRect2() uses the following algorithm. First the function determines the position of the main axis of the coordinate system. It locates the intersection points between a set of parallel search lines, or rake, and the edge of an object. The function determines the intersection points based on their contrast, width, and steepness. The function calculates a best-fit line using the points found. This line defines the main axis of the coordinate system. The function then locates the intersection points between a set of parallel search lines that are perpendicular to the main axis and the edge of the object. It calculates a hit-line to the object from the edge closest to the search area detected and perpendicular to the main axis. This line defines the secondary axis of the coordinate system. The intersection between the main axis and secondary axis is the origin of the coordinate system.

Image Types Supported

IMAQ_IMAGE_U8, IMAQ_IMAGE_I16, IMAQ_IMAGE_SGL

Parameters

Name	Type	Description
image	Image*	The image which the function uses to compute the coordinate transform.
roi	const ROI*	Defines the area within which the edge detection is performed.
mode	FindTransformMode	Specifies how the function updates the coordinate transform.
baseSystem	CoordinateSystem*	Describes the base coordinate system. This parameter is required and cannot be NULL.
newSystem	CoordinateSystem*	Describes the new coordinate system. This parameter is required and cannot be NULL.
findTransformOptions	const FindTransformRectOptions2*	Specifies options for detecting edges along search lines in each ROI and for overlaying search information
straightEdgeOptions	const StraightEdgeOptions*	Specifies the options used to fit a line in the roi.
axisReport	AxisReport*	On return, contains the axes that were located. Set this parameter to NULL if you do not want to return the axis information.

Return Value

Type	Description
int	On success, this function returns a non-zero value. On failure, this function returns 0. To get extended error information, call imaqGetLastError().

Parameter Discussion

findCoordSysOptions—Set findCoordSysOptions to NULL to use the default options, as follows:

direction	IMAQ_LEFT_TO_RIGHT_DIRECT
showSearchArea	FALSE
showSearchLines	FALSE
showEdgesFound	FALSE
showResult	TRUE
searchAreaColor	IMAQ_RGB_GREEN
searchLinesColor	IMAQ_RGB_BLUE
searchEdgesColor	IMAQ_RGB_YELLOW
resultColor	IMAQ_RGB_RED
overlayGroupName	"" (default group)
edgeOptions.polarity	IMAQ_SEARCH_FOR_ALL_EDGES
edgeOptions.kernelSize	3
edgeOptions.numSearchLines	3
edgeOptions.minThreshold	10.0
edgeOptions.interpolationType	IMAQ_BILINEAR_FIXED
edgeOptions.columnProcessingMode	IMAQ_MEDIAN_COLUMNS