imaqFindEdge

Usage

StraightEdgeReport* imaqFindEdge(Image* image, RotatedRect searchRect, RakeDirection direction, const FindEdgeOptions* options, const CoordinateTransform2* transform);

Purpose

Locates a straight edge in a rectangular search area. This function locates the intersection points between a set of parallel search lines and the edge of an object. The function determines the intersection points based on their contrast and slope and calculates a best-fit line based on these points. Use this function if you expect the angle between the calculated line and the search area to be less than 45 degrees.

Note   This function is obsolete. Use imaqFindEdge2() instead.

Image Types Supported

IMAQ_IMAGE_U8

Parameters

Name	Type	Description
image	Image*	The image which the function uses to compute the location of the edge.
searchRect	RotatedRect	The coordinate location of the rectangular search area the function looks in for the edge.
direction	RakeDirection	The direction the function search for edges along the search lines.
options	const FindEdgeOptions*	Describes how to search for the edge and the information the function overlays to the image.
transform	const CoordinateTransform2*	An optional specification of the coordinate transform for searchRect. This parameter specifies how to transform the location of the edge detection based on the difference between the reference coordinate system and the measurement coordinate system. Set this parameter to NULL if you do not need to transform searchRect.

Return Value

Type	Description
StraightEdgeReport*	On success, this function returns information describing the calculated edge. On failure, this function returns NULL. To get extended error information, call imaqGetLastError(). When you are finished with the information, dispose of it by calling imaqDisposeStraightEdgeReport().

Parameter Discussion

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

threshold	40
width	4
steepness	2
subsamplingRatio	5
showSearchArea	FALSE
showSearchLines	FALSE
showEdgesFound	FALSE
showResult	TRUE

Note  imaqFindEdge() only overlays the edges used in the best-fit line calculation.