title: Reasonable search range for HoughCircles param2?
body: <p>I'm writing a script to auto-detect some circles on a set of photographs. I've probably read every question about HoughCircles on Stack and the recommended approach generally seems to be to brute force both the radius interval and the accumulator threshold (i.e. param2). The range for the radius loop can generally be estimated from other geometric properties of the image, but what is a good approach to limit the search range for param2 automatically?</p>
  
  <p>If anyone has any other tips for optimizing this brute force approach I'd also appreciate it.</p>