Thread Subject: Indices under ellipse in an Image

Hi there,

I've got an binary image with a blob. For this blob I can extract informations using regionprops.
What I now want are the indices of the pixels which are covered from the equivalent ellipe. Drawing the ellipse in a figure is not a problem, but who can I extract the indices?

Any help would be great!!
Here is a code snipped with a picture from somewhere in the net:

I=imread('http://www-roc.inria.fr/gamma/OBJECTS/SCHNAUZER/ANATOMY/tibial-bone-sup.jpeg');
I=rgb2gray(I);
I=I>50;
I=imclose(I,strel(5,disk));
imshow(I);
props=regionprops(I,'centroid','Minoraxislength',...
    'MajorAxisLength','Orientation');
xc=yolk_props.Centroid(:,1);
yc=yolk_props.Centroid(:,2);
ra=yolk_props.MajorAxisLength(:,1);
rb=yolk_props.MinorAxisLength(:,1);
phi=yolk_props.Orientation(:,1);