algorithm for detecting a circle in an image

I'm looking for an alg开发者_如何学编程orithm to detect circles in an image. The image is black and white. The background is white, and the circles don't overlap each other, or any other element in the image. The image includes some other shapes and some text.

If there is some open source .NET library to do this, I would also like to know about it.

Maybe the "Hough Transform" is useful for you. You have to know the circle's size in advance to make it efficient though.

• http://www.cis.rit.edu/class/simg782/lectures/lecture_10/lec782_05_10.pdf
• http://en.wikipedia.org/wiki/Hough_Transform

There was a similar question yesterday, where the "Hough Transform", and some image processing libraries (though not for .NET) were proposed:

Image Processing Programming

I was looking for the same thing and what I have found to work best for now is using Mathlab (Image Processing Toolbox). It has good amount of options that lets you try different processing algorithms, threshold level and range of circle's radius.