magnify.m

Contains Rsa and program for magnification of a small image.

clc;
clear all;

%Interpolation
im=imread('t.jpg');
im=rgb2gray(im);

[h w]=size(im);
for i=1:2:2*h
    for j=1:2:2*w
        im1(i,j)=im((i+1)/2,(j+1)/2);
    end;
end;
for i=2:2:2*h
    for j=2:2:2*w
        im1(i,j)=0;
    end;
end;

%Column interpolation
for i=1:2:2*h
    for j=2:2:2*w
        if j~=2*w
            im1(i,j)=round((double(im1(i,j-1))+double(im1(i,j+1)))/2);
        else
            im1(i,j)=round((double(im1(i,j-1)))/2);
        end;
    end;
end;
% Row interpolation
for i=2:2:2*h
    for j=1:1:2*w
        if i~=2*h
            im1(i,j)=round((double(im1(i-1,j))+double(im1(i+1,j)))/2);
        else
            im1(i,j)=round((double(im1(i-1,j)))/2);
        end;
    end;
end;
figure(1);
imshow(im,[0,255]);
title('Original image');
figure(2);
imshow(im1,[0,255]);
title('Magnified image by interpolation');

clear all;

im=imread('t.jpg');
im=rgb2gray(im);
[h w]=size(im);
for i=1:2:2*h
    for j=1:2:2*w
        im2(i,j)=im((i+1)/2,(j+1)/2);
    end;
end;
for i=2:2:2*h-1
    for j=2:2:2*w-1
        im2(i,j)=0;
    end;
end;
imag=conv2(double(im2),double(ones(2,2)));
figure(3);
imshow(imag,[0,255]);
title('Magnified image by replication');