Detecting Circles within an image

问题

I'm currently using EmguCV to run shape detection on an image of a shooting range target:

But no matter my settings in the code (below):

double cannyThreshold = 180; double circleAccumulatorThreshold = 170; CircleF[] circles = CvInvoke.HoughCircles(uimage, HoughType.Gradient, 2.0, 1.0, cannyThreshold, circleAccumulatorThreshold, 5);

I can only seem to find three circles, of which one is wrong.

Am I going about this incorrectly? I'm using the default example for shape detection included with Rev3.0 EmguCV.

回答1:

1. Find edges first (see Sobel operator or Canny for example)
2. Find contours, after that contours will represent circles
3. Filter contours by area
4. Use minEnclosingCircle for each contour to get center and radius.

来源：https://stackoverflow.com/questions/34190594/detecting-circles-within-an-image