Write a program in MatLab to remove background of an image.

clc;
clear all;
close all;

f=imread('n.jpg');
f=rgb2gray(f);
sub=zeros(size(f));
[ROW COLUMN]=size(sub);
f=im2double(f);

% Global Thresholding
T=0.5*(min(f(:))+max(f(:)));
done=false;
while ~done
    g=f>=T;
    Tn=0.5*(mean(f(g))+mean(f(~g)));
    done=abs(T-Tn)<0.1;
    T=Tn;
end
r=im2bw(f,T);
R=double(r);
%Image Subtraction
for i=1:ROW
        for j=1:COLUMN
            sub(i,j)=R(i,j)-f(i,j);
        end
end
% Sliding Neighborhood Normalization
fun = @(x) mode(x(:));
B = nlfilter(sub,[3 3],fun);

figure;
subplot(2,2,1),imshow(f),title('Original Image');
subplot(2,2,2),imshow(r),title('Global Thresholding - Iterative Method');
subplot(2,2,3),imshow(sub),title('Subtracted Image');
subplot(2,2,4),imshow(B),title('Final Result');