MATLAB: How to use Two-Dimensional True Compression on arbitrarly sized images

Question

I want to use wcompress(…)

https://se.mathworks.com/help/wavelet/examples/two-dimensional-true-compression.html

On images of varying size that is not a power of two.

What is the best way to do this?

Answer 1

Since wcompress works only on images of sizes with power of 2, you could either

• resize the images to a particular size like (256, 512 etc)
• pad the images with zeros

You can use padding if you do not want any loss of information in the images, as resizing might change the original information in the images.

im = imread('path/to/image');
% Resize
new_im = imresize(im, [256, 256]);
% Padding
[m, n] = size(im,1:2);
% m,n should be less than 256, else use a number greater than 256
new_m = (256-m)/2; 
new_n = (256-n)/2; 
new_im = padarray(im, [new_m, new_n]);

For more information on imresize and padarray, you can refer to the following links:

https://www.mathworks.com/help/images/ref/imresize.html

https://www.mathworks.com/help/images/ref/padarray.html