a = imread('a1.bmp');
[x1,y1] = find(a(:,:,1) ~= 133 & a(:,:,2)~= 230 & a(:,:,3)~=242)
g = figure;
EllipseDirectFit([x1 y1],a)

% FIX b's 133/230/250
b = imread('b1.bmp');
[x2,y2] = find(b(:,:,1) ~= 133 & b(:,:,2)~= 230 & b(:,:,3)~=250)
h = figure;
EllipseDirectFit([x2 y2],b)