syn.m

center of circle usin circum points

im = imread('iris.png');
img = rgb2gray(im);
imbw= im2bw(img ,0.5);
imbwo = bwareaopen(imbw,3000);
%imshow(imbw);
%subplot(1,2, 1); subimage(imbw)
%subplot(1,2, 2); subimage(imbwo)

rows=size(imbw, 1);
cols=size(imbw, 2);

circ=zeros(3,2);

for i=(cols):-1:(cols/2)
    if imbw((rows/2), i)== 1
        if imbw((rows/2),(i-1) )==0 
            circ(1,1)= i; circ(1, 2)= (rows/2);
            break;
        end
    end
end

for i=(rows):-1:(rows/2)
    if imbw( i, (cols/2))== 1
        if imbw((i-1),(cols/2) )==0 
            circ(2,1)= (cols/2); circ(2, 2)= i;
            break;
        end
    end
end

for i=(cols):-1:(cols/2)
    if imbw((rows/3), i)== 1
        if imbw((rows/3),(i-1) )==0 
            circ(3,1)= i; circ(3, 2)= (rows/3);
            break;
        end
    end
end

circ = int32(circ);
xa=circ(1,1);ya=circ(1,2);
xb=circ(2,1);yb=circ(2,2);
xc=circ(3,1);yc=circ(3,2);
unkn = int32(zeros(3,3));
known = int32(zeros(3,1));
vals = int32(zeros(3,1));
unkn = [2*xa 2*ya 1 ; 2*xb 2*yb 1; 2*xc 2*yc 1]
known = [-(xa^2+ya^2);-(xb^2+yb^2);-(xc^2+yc^2)]
vals= inv(unkn)*known;
g= vals(1,1);
f=vals (2,1);