circle or blob detection

[asda333]

Hey guys

http://i41.tinypic.com/2ela0w6.jpg

this is the input image, which i am testing on as well as the same image but the paper at an angle, and i want to find a way to detect the circles on the page and find the locations of the centres of the circle.

I have tried houghcircles but it doesn't seem to detect the circles and don't know if blob detection would work.

want it to detect those circles, even when an object is placed in the middle, as with corner detection using squares, the corner gets directed to the object in the middle so looking for a robust feature detection, location and maybe tracking if possible.

thanks