Matlab椭圆拟合：快速获取中心与轴长

以下为matlab采用最小二乘法的椭圆拟合程序：

function a = fitellipse(X,Y)

% FITELLIPSE Least-squares fit of ellipse to 2D points.
%        A = FITELLIPSE(X,Y) returns the parameters of the best-fit
%        ellipse to 2D points (X,Y).
%        The returned vector A contains the center, radii, and orientation
%        of the ellipse, stored as (Cx, Cy, Rx, Ry, theta_radians)
%
% Example: Run fitellipse without any arguments to get a demo
if nargin == 0
% Create an ellipse
t = linspace(0,2);

Rx = 300
Ry = 200
Cx = 250
Cy = 150
Rotation = .4 % Radians

x = Rx * cos(t);
y = Ry * sin(t);
nx = x*cos(Rotation)-y*sin(Rotation) + Cx;
ny = x*sin(Rotation)+y*cos(Rotation) + Cy;
% Draw it
plot(nx,ny,'o');
% Fit it
fitellipse(nx,ny)
% Note it returns (Rotation - pi/2) and swapped radii, this is fine.