How to display an image randomly

I am trying to display stimuli, but struggling as I am new to Matlab. How can I display stimuli (images) randomly from a folder in my documents? I want to use every image, but don't want to use the same picture more than once. Thanks

To be more clear, if I have an image in Documents --> Thesis --> Images how do I call this image to be displayed?

Answer 1

[Guillaume]

Use randperm to create a random ordering of your images. The code would go something like:

root = 'C:\somewhere\somefolder';
images = dir(fullfile(root, '*.png'));  %or whatever extension you use
order = randperm(numel(images));
for idx = 1:numel(img)
   currentimg = imread(fullfile(root, images(order(idx)).name));
   imshow(currentimg);
   %...
end

[Erin Krahn]

the screen just turned black and didn't do anything... any idea what I could be doing wrong?

[Guillaume]

Impossible to know because:

• "the screen just turned black and didn't do anything" is meaningless as a diagnostic. Surely, your whole computer monitor didn't turn black. And what did you expect the screen to do?
• we don't know what exact code you used. Note that the %... was meant for you to add whatever processing you wanted to do. If you were to use the code above without any modification then at the very least I would add a drawnow and a pause(1).

If the images do not display properly, you can replace the imshow call by

imshow(currentimg, []);

read the documentation of imshow to know the difference between the two syntax.

[Walter Roberson]

Also, add

drawnow() after the imshow()