Generate .mat of Images - Matlab

Question

How can I create a .mat file which holds a bunch of images in matlab?

I'm using the images as a training set, so figured it would be easier to load from a .mat than load 100+ images every time I run the program.

If I'm thinking about this the wrong way, please point me in the right direction. Thanks.

Create a 4D Matrix and store that into the mat file? If the sizes of the images are different, use cell matrices. — Divakar, Mar 05 '14 at 17:13

herohuyongtao · Accepted Answer · 2014-03-05T18:22:26.963

1

You can simply combine all images (each of which is a 3D matrix for color images) into a 4D matrix with last dimension is the total number. And save this 4D matrix to a .mat file for later loading.

For grayscale images, you only need to combine them into a 3D matrix as each of which is 2D.

As commented by @Divakar, you may need to combine them into a cell array if the sizes of the images are not consistent.

Edit: Suppose you have combined the images into a 3D/4D matrix called data, you can use save data; to save it into disk and use load data; to load it back.

edited Mar 05 '14 at 18:22

answered Mar 05 '14 at 17:53

herohuyongtao

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Is that just an array of 3d matrices if they're the same size? and using a cell array if they images differ? – Reanimation Mar 05 '14 at 17:55
@Reanimation Yes. Each one is a 3D. You can combine them into a 4D. – herohuyongtao Mar 05 '14 at 17:57
Ok thanks guys. I'll give it a shot in matlab. Is there a function to export a 4D matrice as a file? – Reanimation Mar 05 '14 at 18:16
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Thanks. This source helped also. http://www.mathworks.co.uk/matlabcentral/answers/17692-creating-mat-file – Reanimation Mar 05 '14 at 18:41

Generate .mat of Images - Matlab

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