dataset = dir('/Users/Desktop/Image Dataset');
All the entries in dataset (including the '.' and '..' directories) are relative to "/Users/Desktop/Image Dataset".
numFiles = length(dataset);
mydata = cell(1,numFiles);
for k = 1:numFiles
mydata{k} = imread(dataset(k).name);
There are at least two problems with this line.
1) You're not trying to read the data files from "/Users/Desktop/Image Dataset", you're trying to read them from somewhere on the MATLAB search path. Use the fullfile function to include the path name in the input to imread. This contributes partly to MATLAB being unable to find the file. But the main reason is:
2) You're assuming all the entries in dataset refer to image files. That output from dir will contain at least two elements that aren't, the aforementioned '.' and '..' directories. To resolve this you can prune all entries that refer to directories from dataset before calculating numFiles.
dataset = dataset(~[dataset.isdir]);
Continuing on with the rest of your code:
axes(handles.axes1)
imshow(mydata{k})
Are you sure you want to do this? Unless this is a simplified version of your problem, the image in mydata{1} will at most flicker on the screen for as long as it takes MATLAB to read the data for the second file. [In actuality, it probably won't even show for that long since there's no drawnow command in your loop.]
end
