how to save the cropped image in to list and add

i wanted the cropped image to save and then add all those area of the cropped image

{projectdir = 'E:\SHIVA BACKUP\THYROID\P1\newcodes\data1\13002';
%y = 72;
X = zeros(128, 128, 1, 72,'uint16');
% Read the series of images.
% for p=1
p=1;
   thisfile = sprintf('IM_%d.dcm', p);
   filename = fullfile( projectdir, thisfile );
   imdata = dicomread(filename);
   imsize = size(imdata);
   if ~isequal( imsize, [128 128 1 72] )
     fprintf('file is unexpected size %s instead of [128 128 1 72], skipping "%s"\n', mat2str(imsize), filename);
   else
     X(:, :, :, :,p) = imdata;
   end
   figure();
   montage(X(:,:,:,:,p), [0 100])

    a=zeros(128,128,72) ;

for i=1:18
 a=getpix(X(:,:,:,i));%i have a function with getpix(grayscale) to crop the image
 a.list();
 %  u=edge(a,'canny','both');
%  v{i}=bwmorph(u,'skel',inf);
% %v=bwmorph(u,'skel',inf);
%  figure()
% montage(a,[0 100])
end}

In an assignment  A(:) = B, the number of elements in A and B must be the same.

Error in Untitled8 (line 22)
 a(i)=getpix(X(:,:,:,i));

Answer 1

[KSSV]

In

   a(i)=getpix(X(:,:,:,i));

Check the size of getpix(X(:,:,:,i)) and assign it to a. Here you have considered a as vector but the output getpix(X(:,:,:,i)) is not a number, it seems to be a array/ matrix.

Read about debuger in matlab. It help you in understanding code a lot.

https://in.mathworks.com/help/matlab/matlab_prog/debugging-process-and-features.html