@axtimwalde @StephanPreibisch So I could not find the circle Ransac git repo but I figured out the math to do it, we need a regression step to determine the model parameters (3 in this case) and the shortest distance of a point from the circle, which I have. I will make a repo on my Github with this model along with ellipse model which should be able to fit circle and ellipse to a set of points in 2 and 3D, this is going to use the mpicbg models that you guys made and as of now has a line and a polynomial model for 2 dimensions. I am going to do this next week and then share the repo with you. If you are okay with this I can go ahead and do this, in the meantime @tinevez can work on his Hough based approach and in future maybe integrate it with our repo for finding circles and ellipses in 2 and 3D. Sounds good?