complement of an image

How to display an image like this:

Answer 1

[Stephan]

I = fliplr(imread('cameraman.tif'));
I1 = triu((I),1);
I2 = tril(imcomplement(I));
I_res = fliplr(I1+I2);
imshow(I_res)

BTW: Did you notice that you can accept and/or vote for useful answers?

[Sadeq Ebrahimi]

Thank you very much, I've been stuck with this problem for weeks

Answer 2

[Sushmita Dey]

I=imread('https://picload.files.wordpress.com/2014/02/blissful-nature-rain-n-flower.jpg');

J=imcomplement(I);

imshow(I,J,'montage')

title('complement of image')