imaqFindConcentricEdge
Usage
StraightEdgeReport* imaqFindConcentricEdge(Image* image, Annulus searchArea, ConcentricRakeDirection direction, const FindEdgeOptions* options, const CoordinateTransform2* transform);
Purpose
Locates a straight edge in a annular search area. This function locates the intersection points between a set of concentric 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.
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. |
| searchArea | Annulus | The coordinate location of the annular search area the function looks in for the edge. |
| direction | ConcentricRakeDirection | 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 searchArea. 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 searchArea. |
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 |