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How to join or merge two Image Data Stores?

Asked by kowshik Thopalli on 26 Feb 2017
Latest activity Commented on by Yifan Dong on 18 Sep 2018
If I have two image datastores and I wish to concatenate them. How can I do that?
Thanks

  1 Comment

It was a bit tricky but I was able to merge 2 datastores as follows:
imds1 = imageDatastore(location of DS 1,'IncludeSubfolders',true,'LabelSource','foldernames');
imds2 = imageDatastore(imds2 location,'IncludeSubfolders',true,'LabelSource','foldernames');
% create a dummy dataset with the same size of the combined datastores (if ds1 has 100 images and ds2 has 100 images then dummy has 200 images. I made a folder with some photos with equal number of the 2 datastores)
dummy = imageDatastore('Dummy data store locaation','IncludeSubfolders',true,'LabelSource','foldernames');
% note: below this line you can use any datastore variable you want to merge including the ones you get after splitting training and testing
dummy.Files=[imds1.Files;imds2.Files];
dummy.Labels=[imds1.Labels;imds2.Labels];
% Now dummy is the new combined datastore and you can use all datastore functions

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4 Answers

Answer by Zhiqiang Qiu on 22 Jan 2018
 Accepted Answer

I know it is an ancient problem, but I just to make it a better reference for other people.
imds1 = imageDatastore('imds1 location', ...);
imds2 = imageDatastore('imds2 location', ...);
imds_combine = imageDatastore({'imds1 location', 'imds2 location'}, ...);
Just combine the address of these two locations. The following parameters are all the same.

  1 Comment

that is cool answer! i have very similar problem. when i create the data store the files are not in the same order as in the folder. how can i make that possible? i need it because the label i use is coming from another .csv file. so i need to match the order to process the images easily. can anyone help me on this please?

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Answer by Hana
on 18 Jan 2018

I met the same problem and saw your post. Finally I find out a way:
imds = imageDatastore(cat(1,imds1.Files,imds2.Files))
imds.Labels = cat(1,imds1.Labels,imds2.Labels)
It works for me.

  1 Comment

Brilliant!! Thanks!

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Answer by berkan
on 22 May 2017

allImages.Files=[test1.Files;test2.Files]; allImages.Labels=[test1.Labels;test2.Labels];

  1 Comment

Unfortunately, this produces a struct instead of a new datastore - and I could not find a way to convert it back. This means, that you cannot use the datastore specific functions like "countEachLabel" etc. Does anyone know another solution?

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Answer by KSSV
on 27 Feb 2017

A = imread('ngc6543a.jpg');
B = imread('peppers.png');
%%resize the images so that they have same dimensions
A_resize = imresize(A,[size(B,1) size(B,2)]) ;
%%join them
AB = [A_resize B] ;
imshow(AB) ;

  1 Comment

Hi, Thanks for the answer, however I am looking to merge two
imageDatastore

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