Lab 9

Lab 9 of ENSC 180

Code:

 
% Read and show the original 'cameraman.pgm' image
 
originalImage = imread('cameraman.pgm');
 
imshow(originalImage);
 
title('Original Image');
 
disp('Original Size:');
 
disp(size(originalImage));
 
% Display the last 2x2 block of the original image
 
disp('Last 2x2 block of the Original Image:');
 
disp(originalImage(end-1:end, end-1:end));
 
% Calling the upsampling function
 
upsampledImage1 = upsampleImage(originalImage);
 
figure, imshow(upsampledImage1);
 
title('Upsampled Image x2');
 
disp('Upsampled Size x2:');
 
disp(size(upsampledImage1));
 
% Display the last 4x4 block of the upsampled image
 
disp('Last 4x4 block of the Upsampled Image x2:');
 
disp(upsampledImage1(end-3:end, end-3:end));
 
% Save the output image
 
imwrite(upsampledImage1, 'cameraman2.pgm');
 
% Repeat the upward sampling process
 
upsampledImage2 = upsampleImage(upsampledImage1);
 
figure, imshow(upsampledImage2);
 
title('Upsampled Image x4');
 
disp('Upsampled Size x4:');
 
disp(size(upsampledImage2));
 
% Display the last 8x8 block of the second upsampled image
 
disp('Last 8x8 block of the Upsampled Image x4:');
 
disp(upsampledImage2(end-7:end, end-7:end));
 
% Save the output image
 
imwrite(upsampledImage2, 'cameraman4.pgm');
 
end
 
function outputImage = upsampleImage(inputImage)
 
% Convert the input image to double
 
inputImage = double(inputImage);
 
% Create an all-zero matrix of double size
 
[rows, cols] = size(inputImage);
 
outputImage = zeros(2*rows, 2*cols);
 
% Copy the input image to the new matrix with a step size of 2
 
outputImage(1:2:end, 1:2:end) = inputImage;
 
% Row interpolation
 
% For odd-indexed row
 
outputImage(1:2:end, 2:2:end-1) = (outputImage(1:2:end, 1:2:end-2) + outputImage(1:2:end, 3:2:end))/2;
 
% For the last column of each row, copy its left neighbor's value
 
outputImage(1:2:end, end) = outputImage(1:2:end, end-1);
 
% Column interpolation
 
% For the newly created columns and the original ones except the last row
 
outputImage(2:2:end-1, :) = (outputImage(1:2:end-2, :) + outputImage(3:2:end, :))/2;
 
% For the last row, copy its above neighbor's value
 
outputImage(end, :) = outputImage(end-1, :);
 
% Convert the output image to uint8
 
outputImage = uint8(outputImage);
 
end

Output:

Term out