Loading multiple images in MATLAB

Question

Here is the desired workflow:

• I want to load 100 images into MATLAB workspace
• Run a bunch of my code on the images
• Save my output (the output returned by my code is an integer array) in a new array

By the end I should have a data structure storing the output of the code for images 1-100.

How would I go about doing that?

Answer 1

If you know the name of the directory they are in, or if you cd to that directory, then use dir to get the list of image names.

Now it is simply a for loop to load in the images. Store the images in a cell array. For example...

D = dir('*.jpg');
imcell = cell(1,numel(D));
for i = 1:numel(D)
  imcell{i} = imread(D(i).name);
end

BEWARE that these 100 images will take up too much memory. For example, a single 1Kx1K image will require 3 megabytes to store, if it is uint8 RGB values. This may not seem like a huge amount.

But then 100 of these images will require 300 MB of RAM. The real issue comes about if your operations on these images turn them into doubles, then they will now take up 2.4 GIGAbytes of memory. This will quickly eat up the amount of RAM you have, especially if you are not using a 64 bit version of MATLAB.