How can I rescale an image three dimensions (128*128*3) into 2D as (128*128) double ? please

Hi , i have set of images with dimensions (128*128*3) unit8 , i need convert them into 2D double as (128*128) double ? this code just provide me 128*128*3 !

digitDatasetPath = fullfile('C:\....\Resized dataset'); 

imds = imageDatastore(digitDatasetPath, ...
    'IncludeSubfolders',true,'LabelSource','foldernames');
for i=1:length(imds.Labels)
img=readimage(imds,i);
 img1 = imresize(img,[128 128]);
 imwrite(img1,cell2mat(imds.Files(i)))
end

Answer 1

[Matt J]

rgb2gray(img)

[Furat Alobaidy]

thanks you a lots.

Answer 2

[Walter Roberson]

It is not possible to do that by resizing images.

You have color images, and when you want 2D output then you need to convert so they are not color. The most common conversion for that is grayscale, but there are other possibilites. For example you might want to convert to HSV saturation.

For grayscale:

 imwrite( rgb2gray(img1), imds.Files{i} )    %with no imresize

However, you are overwriting your original files, which is seldom a good idea.

Have you considered using a transform data store ? https://www.mathworks.com/help/matlab/ref/matlab.io.datastore.transform.html

And pixelLabelImageStore can transform to or from rgb:

https://www.mathworks.com/help/vision/ref/pixellabelimagedatastore.html?s_tid=srchtitle#mw_4d35e9a5-7306-4ca5-ad2d-95e91f7c3012

[Furat Alobaidy]

thanks a lots for clarification.