HoughCircles far distance

asked 2015-02-17 06:56:44 -0500


I'm a beginner in OpenCV. I developed some apps for Android and now I want to develop an App with OpenCV4Android. First I want to detect some Circles for example Coins. I tried Threshold (with Binary or Otsu), Erode, Canny, GaussianBlur in different variations, but always my HoughCircles after all this "filters" return no circles or only some if I my camera is really near (~5cm) to the circles. But I want that it recognizes the circles also from a distance more than 30cm. I use HoughCircles like this:

int iUpperThreshold = 200;
    int iMinRadius = 0;
    int iMaxRadius = 0;
    int iAccumulator = 100;
    Imgproc.HoughCircles(mat, matCirclesOut, Imgproc.CV_HOUGH_GRADIENT, 1, 1, iUpperThreshold, iAccumulator, iMinRadius, iMaxRadius);

I played with every parameter, but I never get circles from far distance.

Has anyone an idea what I can do, or is HoughCircles not the right way in this case?

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As a starter: maybe the code presented in this question might help you: http://answers.opencv.org/question/55...

Guanta gravatar imageGuanta ( 2015-02-17 09:40:14 -0500 )edit