Presenting random images from a file, where each image is presented only once?

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Robert Newman
Robert Newman 2019-5-9
评论： Jeff Miller 2019-5-10
Hi,
This is my fourth day of coding ever so bear with me.
Right now I have a folder with images. I want to present each image from the folder randomly once and only once for a certain number of trials.
So far my code looks like this. It successfully presents a random image from the folder, but it can use the same images over again which I don't want.
How do I make it so that each image in the folder is displayed once and only once?
Thank you in advance for your help!
emotionalImageDirectory = 'C:\PsychExperiment\Emotional';
imageTwoVarOne = dir([emotionalImageDirectory '\*.jpg']);
imageTwoVarTwo = numel(imageTwoVarOne);
idx = randi(imageTwoVarTwo);
loadimageTwo = imread(imageTwoVarOne(idx).name);

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采纳的回答

Jeff Miller
Jeff Miller 2019-5-10
Store a random sequence of the images in advance and then cycle through them one by one. Something like this,
emotionalImageDirectory = 'C:\PsychExperiment\Emotional';
imageTwoVarOne = dir([emotionalImageDirectory '\*.jpg']);
imageTwoVarTwo = numel(imageTwoVarOne);
imageseq = randperm(imageTwoVarTwo);
for i=1:imageTwoVarTwo % or the number of trials you want, which may be less than the n of images
idx = imageseq(i);
loadimageTwo = imread(imageTwoVarOne(idx).name);
end
  2 个评论
Robert Newman
Robert Newman 2019-5-10
Thank you! What if I wanted to present two images at the same time? Let's say I had another subfolder with non-emotional images, and I wanted them to also be presented once and only once and in a random order. I've tried using a nestled for loop with the break function, but so far this hasn't worked. i.e. something like
emotionalImageDirectory = 'C:\PsychExperiment\Emotional';
imageTwoVarOne = dir([emotionalImageDirectory '\*.jpg']);
shuffleImagesTwo = randperm(numel(imageTwoVarOne));
for b =1:shuffleImagesTwo
loadimageTwo = imread(imageTwoVarOne(b).name);
break
end
Jeff Miller
Jeff Miller 2019-5-10
Not sure that I follow, but maybe you want two random sequence holders, something like this:
emotionalImageDirectory = 'C:\PsychExperiment\Emotional';
imageTwoVarOne = dir([emotionalImageDirectory '\*.jpg']);
imageTwoVarTwo = numel(imageTwoVarOne);
imageseq = randperm(imageTwoVarTwo);
nonemotionalImageDirectory = 'C:\PsychExperiment\NonEmotional';
nonemoimageTwoVarOne = dir([nonemotionalImageDirectory '\*.jpg']);
nonemoimageTwoVarTwo = numel(nonemoimageTwoVarOne);
nonemoimageseq = randperm(nonemoimageTwoVarTwo);
for i=1:ntrials
idxemo = imageseq(i);
idxnonemo = nonemoimageseq(i);
loadimageTwo = imread(imageTwoVarOne(idx).name);
nonemoloadimageTwo = imread(nonemoimageTwoVarOne(idx).name);
% Now display the two images for this trial?
end

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