imaqDetectLines
Usage
LineMatch* imaqDetectLines(const Image* image, const LineDescriptor* lineDescriptor, const CurveOptions* curveOptions, const ShapeDetectionOptions* shapeDetectionOptions, const ROI* roi, int* numMatchesReturned);
Purpose
Searches for lines in an image.
Image Types Supported
IMAQ_IMAGE_U8
Parameters
|
Name
|
Type
|
Description
|
|---|---|---|
| image | const Image* | The image on which to detect lines. |
| lineDescriptor | const LineDescriptor* | A structure that describes the lines to search for in the image. This parameter is required and cannot be NULL. |
| curveOptions | const CurveOptions* | Describes how the function identifies the curves in the image. This function does not support identifying curves with subpixel accuracy and therefore ignores the subpixelAccuracy element of this parameter. |
| shapeDetectionOptions | const ShapeDetectionOptions* | The options to use when detecting lines. |
| roi | const ROI* | The region of interest applied to the image that specifies where lines can be detected. Set this parameter to NULL to search the entire image. |
| numMatchesReturned | int* | On return, the number of lines that the function matched. Set this parameter to NULL if you do not wish to return information about the number of matched lines. |
Return Value
| Type |
Description |
|---|---|
| LineMatch* | On success, this function returns an array of information about each match found. On failure, this function returns NULL. To get extended error information, call imaqGetLastError(). When you are finished with the return value, dispose of the pointer by calling imaqDispose(). |
Parameter Discussion
curveOptions—Set curveOptions to NULL to use the default curve options, as follows:
| extractionMode | IMAQ_NORMAL_IMAGE |
| threshold | 75 |
| filterSize | IMAQ_NORMAL |
| minLength | 25 |
| rowStepSize | 15 |
| columnStepSize | 15 |
| maxEndPointGap | 10 |
| onlyClosed | FALSE |
| subpixelAccuracy | FALSE |
shapeDetectionOptions—Set shapeDetectionOptions to NULL to use the default shape detection options, as follows:
| mode | IMAQ_GEOMETRIC_MATCH_SHIFT_INVARIANT |
| orientationRanges | NULL |
| numOrientationRanges | 0 |
| scaleRange | {75, 125} |
| minMatchScore | 800 |