exp01.m

Program for : 1) ZOOMING , 2) SHRINKING &

% % % % % % % % % % % % % % % %
% Program for :               %
%    1) ZOOMING ,             %
%    2) SHRINKING &           %
%    3) GRAY LEVEL RESOLUTION %
%  the image                  %
% % % % % % % % % % % % % % % % 

clc; 
close all;
clear all;

% READING THE IMAGE

A = imread('img_01.bmp'); 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%CONVERTING THE IMAGE INTO GRAY SCALE USING DYNAMIC RANGE 0 TO 255 %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% CONVERTING 'unit8' VALUES TO 'double' WITH DYNAMIC RANGE [0 255]

A_img = im2double(A)* 255;
% Separating RGB Components 
R = A_img(:,:,1);
G = A_img(:,:,2);
B = A_img(:,:,3);
 
% Converting to Gray Scale Image
Y = 0.299*R + 0.587*G + 0.114*B;
% Rounding of Y
Y = round (Y);

% Displaying original image and its gray scale version
figure;
imshow(Y/255); title('Gray Scale Image');

% Writing the gray scale image
imwrite(Y/255,'a1.bmp');

[R C] = size (Y);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%ZOOMING USING PIXEL REPLICATION METHOD
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
z = input(' Enter the Zooming Factor : ');

for y = 1:R
    for x = 1:C
        a1 = Y(x,y); 
        a2 = a1;
        m = (a2-a1)/(z-1);
        for b = 0:(z-1)           
            Y_new((x*z)-(z-1)+b,y) = a1 + m*b;
        end
    end
end

for x = 1:(C*z)
    for y = 1:R
        a1 = Y_new(x,y); 
        a2 = a1;
        m = (a2-a1)/(z-1);
        for b = 0:(z-1)
            Y1a(x,((y*z)-(z-1)+b)) = a1 + m*b;
        end
    end
end

figure;
imshow(Y1a/255); title('Zoom by Pixel Replication');
imwrite(Y1a/255,'a2.bmp');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%ZOOMING USING BILINEAR INTERPOLATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[R C] = size (Y);

z1 = input(' Enter the Zooming Factor : ');
i=1;
for y=1:C
    j=1;
    for x=1:R
        a1=Y(x,y);
        if x==R
            a2=a1;
        else
            a2=Y(x+1,y);
        end
            slope= (a2-a1)/z1;
            for d=0:(z1-1)
                Y11(j,i) = slope*d + a1;
                j=j+1;
            end
    end
    i=i+1;
end

[R1 C1] = size (Y11);
i=1;
for x=1:R1
    j=1;
    for y=1:C1
        a1=Y11(x,y);
        if y==C1
            a2=a1;
        else
            a2=Y11(x,y+1);
        end
            slope= (a2-a1)/z1;
            for d=0:(z1-1)
                Y1b(i,j) = slope*d + a1;
                j=j+1;
            end
    end
    i=i+1;
end
% Displaying zoomed image 
figure;
imshow(Y1b/255); title('Zoomed Image');
% writing the gray scale image
imwrite(Y1b/255,'zoom_1.bmp');



%%%%%%%%%%%%%%%%%%%%%%%%
%% SHRINKING OF IMAGE %%
%%%%%%%%%%%%%%%%%%%%%%%%

shrink = 4;
i=1;
for x=1:shrink:R
    j=1;
    for y=1:shrink:C
        Y2(i,j) = Y(x,y);
        j=j+1;
    end
    i=i+1;
end
figure;
subplot(1,2,1);imshow(Y2/255); title('Shrink Image');
subplot(1,2,2); imshow(Y/255); title('Gray Scale Image');
imwrite(Y2/255,'a3.bmp');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%ZOOMING OF SHRUNKEN IMAGE %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
z = 4;

[R1 C1] = size (Y2);

for y = 1:R1
    for x = 1:C1
        a1 = Y2(x,y); 
        a2 = a1;
        m = (a2-a1)/(z-1);
        for b = 0:(z-1)           
            Y_new((x*z)-(z-1)+b,y) = a1 + m*b;
        end
    end
end

for x = 1:(C1*z)
    for y = 1:R1
        a1 = Y_new(x,y); 
        a2 = a1;
        m = (a2-a1)/(z-1);
        for b = 0:(z-1)
            Y3(x,((y*z)-(z-1)+b)) = a1 + m*b;
        end
    end
end

figure;
imshow(Y3/255); title('Zooming of shrukan image by Pixel Replication');
imwrite(Y3/255,'a5.bmp');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% CHANGING GRAYSCALE RESOLUTION %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

input('Press ENTER for imge with Changing Grayscale Resolution;  ');
h=zeros(1,256);            %Array of zeros(1 X 256)
n=input('enter no of bits: ');
k=1;
for i=0:(2^n-1)        
    for j=1:256/(2^n)
        h(1,k)=i;
        k=k+1;
    end
end
h=h*(256/2^n);
for x=1:R
    j=1;
    for y=1:C
        Y4(i,j)=h(1,Y(x,y)+1);
        j=j+1;
    end
    i=i+1;
end
figure;
subplot(1,2,1); imshow(Y4/255); title('Image with changed grayscale resolution');
subplot(1,2,2); imshow(Y/255); title('Gray Scale Image');
imwrite(Y4/255,'a4.bmp');