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J.D. Maldonado
F.X.Timmes, my vitae
Lots of codes exist for fitting a set a data to a straight line. How about fits to other specific conic sections? Strange as it may sound, this is an active field of research in computer vision in 2009. Some references that I found very useful are, in historical order, Fitzgibbon et al 1999, Halir and Flusser 1998, O'Leary and Zsombor-Murray 2004, Harker et al 2008. So, I deleted my old codes and am giving this effort a fresh start.
For fitting an ellipse try using fit_ellipse.f90, for a hyperbola fit_hyperbola.f90, for circle fit_circle.f90, and if you do not care what kind of conic is fit try using fit_nonspecific_conic.f90. These programs will generate noisy (x,y) data for any of the conic sections (interesting problem in its own right), fit the data to the specified conic and report key attributes such as the center coordinates, foci coordinates, lengths of the semi-major and semi-minor axes, rotatation of the conic.
pdf showing full rotation to noiseless data pdf showingfull rotation to noisy data |
fitting an ellipse to hyperbola data |
pdf showing full rotation to noiseless data pdf showing full rotation to noisy data |
fitting a hyperbola to ellipse data |
pdf version |
pdf version |
Next up for these pages is a parabola specific fit to the algebraic distance (not too hard), and then geometric distance fitting for the ellipse, hyperbola, and parabola (medium).