OpenCV Detect Circles in iOS

Question

I am trying to detect circles in an image (that contains an empty plate).

I have tried using HoughCircles and minEnclosingCircle but no luck using the code in my iOS app.

I code I am trying to port to iOS is located at http://docs.opencv.org/doc/tutorials/imgproc/imgtrans/hough_circle/hough_circle.html#hough-circle

Could someone please point me in the right direction as to how I convert this code to Objective C..