title: Detect circles in openCV
body: <p>I have a problem with choosing right parameters for HoughCircles function. I try to detect circles from video. This circles are made by me, and has almost the same dimension. Problem is that camera is in move. </p>
  
  <p>When I change maxRadius it still detect bigger circles somehow (see the right picture). I also tried to change param1, param2 but still no success.
  <a href="https://i.stack.imgur.com/rZ7iG.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rZ7iG.png" alt="Left-original picture, Right - after blur and detected circles "></a></p>
  
  <pre><code>gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    blurred = cv2.medianBlur(gray, 25)#cv2.bilateralFilter(gray,10,50,50)
  
  
    minDist = 100
    param1 = 500
    param2 = 200#smaller value-&gt; more false circles
    minRadius = 5
    maxRadius = 10
    circles = cv2.HoughCircles(blurred, cv2.HOUGH_GRADIENT, 1, minDist, param1, param2, minRadius, maxRadius)
  
    if circles is not None:
      circles = np.uint16(np.around(circles))
      for i in circles[0,:]:
          cv2.circle(blurred,(i[0], i[1]), i[2], (0, 255, 0), 2) 
  </code></pre>
  
  <p>Maybe Im using wrong function? </p>