Grey Scale -> RGB images from augmentedImageSource

Hi, I would like to convert grey scale images to [227 227 3]. I'm able to adjust the size using "auimds = augmentedImageSource(imageSize, trainingImages); " but I'm having trouble with converting to RGB (for use with Alex Net).

I've tried:

%grayimg=repmat(grayimg, 1, 1, 3);
%auimds = cat(3, auimds, auimds, auimds);
%auimds(:,:,[1 1 1]);
%RGB = auimds(3, auimds, auimds, auimds);

and the grey2rgb() method

Any suggestions?

[Aditya Patil]

Can you elaborate on the issue you are facing? Share any errors that were shown, and also share the output of the "version" command.

[Samir Gouin]

Version '9.8.0.1359463 (R2020a) Update 1'

Error is in the photo

Answer 1

[Subhadeep Koley]

You can use the ColorPreprocessing Name-Value pair of augmentedImageSource to achieve what you want.

imageSize = [227 227 3];
auimds = augmentedImageSource(imageSize, trainingImages, 'ColorPreprocessing', 'gray2rgb'); % 'trainingImages' is your image datastore

Also if your using MATLAB R2018a or above, you might want to use augmentedImageDatastore instead of the augmentedImageSource due to the Compatibility Considerations.

augmentedImageDatastore is a direct replacement of augmentedImageSource. Like below,

imageSize = [227 227 3];
auimds = augmentedImageDatastore(imageSize, trainingImages, 'ColorPreprocessing', 'gray2rgb'); % 'trainingImages' is your image datastore

[Samir Gouin]

Thanks for your help! I am using version R2020a so I've implemented the second approach. Still getting a size error (please see pic). Any ideas?