fitting an ellipse to my binary iris image ?

nedaa

2012 11월 12

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1 개 추천

I want to fit an ellipse to the boundary of the iris in my edge map eye image in order to segment the iris from the background.i really appretiate your help. the image is :

http://imageshack.us/photo/my-images/94/irisseg2.png/

thanks inadvance.

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Matt J 2012년 11월 12일

MATLAB Online에서 열기

1 개 추천

function report=ellipsefit(XY)
%ELLIPSEFIT - form 2D ellipse fit to given x,y data
%
%  report=ellipsefit(XY)
%
%in:
%
% XY: Input matrix of 2D coordinates to be fit. Each column XY(:,i) is [xi;yi]
%
%out: Finds the ellipse fitting the input data parametrized both as
%     A*x^2+B*x*y C*y^2+D*x+E*y=1 and [x-x0,y-y0]*Q*[x-x0;y-y0]=1
%
% report: a structure output with the following fields
%    
%    report.Q: the matrix Q
%    report.d: the vector [x0,y0]
%    report.ABCDE: the vector [A,B,C,D,E]
%    report.AxesDiams: The minor and major ellipse diameters
%    report.theta: The counter-clockwise rotation of the ellipse.
%
%NOTE: The code will give errors if the data fit traces out a non-elliptic or
%      degenerate conic section.
%
%See also ellipsoidfit
X=XY(1,:).';
Y=XY(2,:).';
M= [X.^2, X.*Y, Y.^2, X, Y, -ones(size(X,1),1)];
[U,S,V]=svd(M,0);
ABCDEF=V(:,end);
if size(ABCDEF,2)>1
      error 'Data cannot be fit with unique ellipse'
  else
      ABCDEF=num2cell(ABCDEF);
  end
[A,B,C,D,E,F]=deal(ABCDEF{:});
Q=[A, B/2;B/2 C];
x0=-Q\[D;E]/2;
dd=F+x0'*Q*x0;
Q=Q/dd;
[R,eigen]=eig(Q);
eigen=eigen([1,4]);
if ~all(eigen>=0), error 'Fit produced a non-elliptic conic section'; end
idx=eigen>0;
eigen(idx)=1./eigen(idx);
AxesDiams = 2*sqrt(eigen);
theta=atand(tand(-atan2(R(1),R(2))*180/pi));
report.Q=Q;
report.d=x0(:).';
report.ABCDE=[A, B, C, D, E]/F;
report.AxesDiams=sort(AxesDiams(:)).';
report.theta=theta;