MATLAB: Set union of Datastores with TransformedDatastores

Question

Given an imageDatastore and some transformation of it, e.g.,

imds1 = imageDatastore({'street1.jpg','peppers.png'});
imds2 = transform(imds1,@(x) imwarp(x,tform));

I would like to form the set union of these data stores in some way so that trainNetwork processes the series of images from both imds1 and imds2 as a single combined set (and similarly with the response data). Is this possible in some way?

I am aware that this functionality is somewhat captured by augmentedImageDatastore, but the operation I describe would open up a variety of data augmentation schemes not currently avaialble.

I am also aware of this thread,

https://www.mathworks.com/matlabcentral/answers/327026-how-to-join-or-merge-two-image-data-stores?s_tid=answers_rc1-2_p2_MLT

but this does not cover what I am pursuing here, because the images in a TransformedDatastore are not physically stored anywhere (nor would I want them to be).

Answer 1

Horizontal (i.e. associated reads)

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cds = combine(imds,otherds);

Vertical (i.e. joining two sets of files into one datastore)

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imds = imageDatastore({'folder1/*.jpg','folder2/*.png'});

Or leave off the extensions

imds = imageDatastore({'folder1/','folder2/'});