MATLAB: Delete part of an image

Question

Hi, explain below what I want to do to see if anyone would know how to fix it.

I start with an image like the following:

Now I make two circles, one with a smaller radius than the other, of which I know both its center and radius. They're not concentric but they never intersect

And finally what I want to achieve is that all the points that are outside the major circle as well as inside the minor circle become black

Answer 1

[m,n]=size(oldImage);
x=(1:n); 
y=(1:m).';
mask = (x-innerCenterX).^2+(y-innerCenterY).^2>=innerRadius^2 & ...
       (x-outerCenterX).^2+(y-outerCenterY).^2<=outerRadius^2 ;
       
newImage=oldImage.*mask;