MATLAB: Vingetting an image using loop

Question

This is my work below I keep getting a black image for my vinColor. Any suggestions?

Color = imread('sunflower.jpg');
Center = size(Color)/2+.5;
[l,h,~] = size(Color);
for x=1:l
    for y=1:h
        d = sqrt((x-Center(1))^2+(y-Center(2))^2);
    end
    D = 246.9261
    r = d./D
end
imshow(Color)
VinColor = Color .* (1-r.^2);
figure(2)
imshow(VinColor)

Answer 1

Hope this works.

colorImg = im2double(imread('kobi.png'));
center = size(colorImg)/2+.5;
[l,h,~] = size(colorImg);
d = zeros(l, h);
for x=1:l
    for y=1:h
        d(x, y) = sqrt((x-center(1))^2+(y-center(2))^2);
    end
end
D = max(d);
r = d./D;
vinColor = colorImg .* (1-r.^2);
figure
montage({colorImg, vinColor})