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POOpenCV HoughCircles
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3387960
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2010-08-02T12:58:28.470
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2011-12-29T16:54:33.607
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Body
Im using Xcode and c++ I have copied the HoughCircles code from the <a href="http://opencv.willowgarage.com/documentation/cpp/feature_detection.html?highlight=circle%20detection#cv-houghcircles" rel="nofollow noreferrer">OpenCV documentation</a>: <pre><code>#include <cv.h> #include <highgui.h> #include <math.h> using namespace cv; int main(int argc, char** argv) { Mat img, gray; if( argc != 2 && !(img=imread(argv[1], 1)).data) return -1; cvtColor(img, gray, CV_BGR2GRAY); // smooth it, otherwise a lot of false circles may be detected GaussianBlur( gray, gray, Size(9, 9), 2, 2 ); vector<Vec3f> circles; HoughCircles(gray, circles, CV_HOUGH_GRADIENT, 2, gray->rows/4, 200, 100 ); for( size_t i = 0; i < circles.size(); i++ ) { Point center(cvRound(circles[i][0]), cvRound(circles[i][1])); int radius = cvRound(circles[i][2]); // draw the circle center circle( img, center, 3, Scalar(0,255,0), -1, 8, 0 ); // draw the circle outline circle( img, center, radius, Scalar(0,0,255), 3, 8, 0 ); } namedWindow( "circles", 1 ); imshow( "circles", img ); return 0; } </code></pre> then modified it like this: <pre><code>int main(int argc, char** argv) { VideoCapture cap(0); if(!cap.isOpened()) return -1; namedWindow( "circles", 1 ); Mat img, gray; for( ;; ) { cap >> img; vector<Vec3f> circles; cvtColor(img, gray, CV_BGR2GRAY); GaussianBlur(gray, gray, Size(7,7), 1.5, 1.5); HoughCircles(img, circles, CV_HOUGH_GRADIENT, 2, img->rows/4, 200, 100 ); imshow( "circles", img ); if(waitKey(30) >= 0) break; } return 0; } </code></pre> I get the error on both cases: error: base operand of '->' has non-pointer type 'cv::Mat' i then replace the -> with . and still get another error. This is the same with the code that i copied from the documentation. My theory is that this happens because its not getting and image or somehting. but when i take the HoughCircles code out, the camera runs fine. Any ideas please??
Tags
<c++><xcode><opencv>
Title
OpenCV HoughCircles
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