circlefit

Below is a demonstration of the features of the circlefit function

Contents

clear; close all; clc;

Syntax

[Vc,R]=circlefit(V);

Description

This function returns the centre Vc and radius R for a circle fitted to the input point set V. The input can be 2D or 3D but the output centre is always a point in 3D space.

Examples

Plot settings

markerSize=30;
lineWidth=3;

Create input circle

n=50; % Number of points on the circle
r=2; % True radius
t=linspace(0,2*pi,n+1)'; t=t(1:end-1); % Angles
V_true=r.*[cos(t) sin(t) zeros(size(t))]; %Circle true coordinates
V=V_true+r/20*randn(size(V_true));

Fit a circle

[Vc,R]=circlefit(V);

nf=250;
r=2;
t=linspace(0,2*pi,nf+1)'; t=t(1:end-1);
Vf=Vc+R.*[cos(t) sin(t) zeros(size(t))];

Visualize result

cFigure; hold on;
hp1=plotV(V,'k.','MarkerSize',markerSize);
hp2=plotV(V_true,'g.-','MarkerSize',markerSize,'LineWidth',lineWidth);
hp3=plotV(Vf,'r-','LineWidth',lineWidth);
legend([hp1 hp2 hp3],{'Noisy input data','True circle','Fitted circle'},'Location','NorthEastOutside')
axisGeom; view(2);
drawnow;

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, [email protected]

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License: https://github.com/gibbonCode/GIBBON/blob/master/LICENSE

GIBBON: The Geometry and Image-based Bioengineering add-On. A toolbox for image segmentation, image-based modeling, meshing, and finite element analysis.

Copyright (C) 2006-2022 Kevin Mattheus Moerman and the GIBBON contributors

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

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Published with MATLAB® R2022a