Convert multiple images in a single .mat file into jpg images

There is a .mat file that contains images and I don't have much information about it. I'd like to convert each of these images stored in the single .mat file to jpg and view them. I would also like to know why these images are stored in a single .mat file as opposed to multiple .mat files. Please help.

Answer 1

[Image Analyst]

Who knows why they chose a single one instead of multiple files. Anyway, to get the images out, assuming they are called iamge1, image2, etc.

s = load(fullFileName)
imwrite('image1.png', s.image1); % Don't use jpg or you'll have compression artifacts.
imwrite('image2.png', s.image2); % Don't use jpg or you'll have compression artifacts.
imwrite('image3.png', s.image3); % Don't use jpg or you'll have compression artifacts.

[Shourya]

Thank you for your response. I am sorry I am not sure how many images there are in that mat file. Could you give me some input on that please.

[Image Analyst]

What do you see in the command window when you do this:

s = load(fullFileName)

[Shourya]

This is what I got.

>> s = load('file_one.mat')

s =

struct with fields:

output_array: [384×4096 double]

[Image Analyst]

I only see one matrix (image) in there, called output_array. Why do you think there are multiple images in there???

s = load(fullFileName)
imwrite('output_array.png', s.output_array); % Don't use jpg or you'll have compression artifacts.

[Shourya]

Hi, Am sorry about the previous message. I had some confusion. Thank you for your response. It was mentioned that there are multiple images in that mat file. They are series of brain MRI images strored as array. I was able to display the image using the above code but I recieve a warning : "Image is too big to fit on screen; displaying at 33% " and the image is not clear since it is big. I get a horizontal long image with patches. Is there a way I can display these series of patchy brain images clearly?

[Image Analyst]

You have to figure out how many patches (images) are across that, and then divide the image up into parts

numImages = 8; % Or whatever it is.
s = load('file_one.mat')
output_array = s.output_array;
[rows, columns, numberOfColorChannels] = size(output_array);
if numberOfColorChannels == 3
    output_array = rgb2gray(output_array);
end

% Extract and display them all in separate subplots.
columnsPerPatch = floor(columns / numImages)
plotRows = ceil(sqrt(numImages));
k = 1;
for col = 1 : columnsPerPatch : columns
    thisImage = output_array(:, col : col + columnsPerPatch - 1);
    subplot(plotRows, plotRows, k);
    imshow(thisImage, []);
    k = k + 1;
end

[Shourya]

Thank you for your response. It worked!