Is it possible to implement principle component analysis on the function imageDatastore?

Hi everyone.

I am new user of MATLAB. I am implementing CNN on the data set that I have and I use the bulid function

imds = imageDatastore(fullfile(pwd,'data'),...
    'IncludeSubfolders',true,'FileExtensions','.dcm',...
        'LabelSource','foldernames');

and I am trying to apply PCA on imds ( dimentinalty reduction ). I notice that there is a function that preformed pca called coeff = pca(imds). However, I recive the following error

    Error using pca (line 168)
The value of X must be a numeric array.

Error in cnn (line 34)
coeff = pca(imds)

which means that imds must be numeric array. Please, If someone can help me to solve this problem??.

Many thanks

[Prakash Shyam Karuppiah]

Had you solved the problem, I am also struck with the same

Answer 1

[Walter Roberson]

No, you can only apply pca to an image that you have read in from the datastore, not to the whole datastore. You will need a loop.

[Prakash Shyam Karuppiah]

Can you please elaborate, I am new user to Matlab ans I need a work around here

[Walter Roberson]

https://www.mathworks.com/help/matlab/import_export/read-and-analyze-image-files.html shows an example. Notice in particular the loop, and the readimage() call.