I am using National Instruments Vision module in Labwindows\CVI
For some reason, when i use the func imaqDetectLines()
, i get FATAL RUN-TIME ERROR: "Angle tracker.c", line 50, col 11, thread id 0x00002004: The program has caused a 'General Protection' fault at 0x6C5AD446.
This is my code:
#include "nivision.h"
#include <userint.h>
#include <cvirte.h>
int main (int argc, char *argv[])
{
int nLines;
ShapeDetectionOptions stShapeDetectionOption;
RangeFloat aAngleRanges[2]={{0,10.0},{10.0,20.0}};
CurveOptions stCurveOptions = {0};
LineMatch *aLm;
LineDescriptor lineDesc;
Image *imageHdl = NULL, *imageDestHdl = NULL;
char temp[1024] ="";
if (InitCVIRTE (0, argv, 0) == 0)
return -1; /* out of memory */
imageHdl = imaqCreateImage (0/*U8*/,1);
imageDestHdl = imaqCreateImage (0/*U8*/,1);
strcpy(temp,"C:\\CVI2013\\Projects\\Angel Tracker\\IMG\\CC01.bmp");
imaqReadFile (imageHdl, temp, NULL, NULL);
imaqEdgeFilter (imageDestHdl, imageHdl, IMAQ_EDGE_SOBEL, NULL);
lineDesc.maxLength = 100;
lineDesc.minLength = 50;
stShapeDetectionOption.minMatchScore = 1;
stShapeDetectionOption.mode = 0;
stShapeDetectionOption.numAngleRanges = 1;
stShapeDetectionOption.angleRanges = aAngleRanges;
stShapeDetectionOption.scaleRange.minValue = 1;
stShapeDetectionOption.scaleRange.maxValue = 10;
stCurveOptions.extractionMode = 0;
stCurveOptions.threshold = 100;
stCurveOptions.filterSize = 1;
stCurveOptions.minLength = 100;
stCurveOptions.rowStepSize = 10;
stCurveOptions.columnStepSize = 10;
stCurveOptions.maxEndPointGap = 1000;
stCurveOptions.onlyClosed = TRUE;
stCurveOptions.subpixelAccuracy = TRUE;
aLm = imaqDetectLines(imageDestHdl, &lineDesc, &stCurveOptions
,&stShapeDetectionOption, NULL, &nLines);
return 0;
}
what i am actually doing is:
Open a BMP file
Edge filltering it with imaqEdgeFilter()
func using SOBEL
Then i want to detect lines with imaqDetectLines()
func
I found the problem.
if you look at the function call:
aLm = imaqDetectLines(imageDestHdl, &lineDesc, &stCurveOptions
,&stShapeDetectionOption, NULL, &nLines);
For the ROI parameter i passed NULL because i got this from The function panel help:
The region of interest applied to the image that specifies where circles can be detected. Set this parameter to NULL to search the entire image.
But, apparently it is a known bug and it will be fixed, so in order to workaround this, just do the following:
ROI *roi;
imaqSetWindowROI (0, NULL);
roi = imaqGetWindowROI (0);
And then send it to the function:
aLm = imaqDetectLines(imageDestHdl, &lineDesc, &stCurveOptions
,&stShapeDetectionOption, roi, &nLines);