MATLAB: How to read multiple images at once

image processingImage Processing Toolbox

I need to read 40 .jpeg images from a directory but can't quite figure it out how to do it. I have tried the following code:

A=dir('myDir');
for n=1:length(A)
eval(['M' num2str(n) '=imread(A(n).name);']);
end

I get the following error message when running the code above: Error using imread (line 370) Can't open file "." for reading; you may not have read permission.

Best Answer

Not eval is not used, to make the code much faster and more reliable.

sPath = 'myDir';
sFile = '*.jpg';
sFull = fullfile(sPath,sFile);
S = dir(sFull);
C = cell(size(S));
for k = 1:numel(S)
    tmp = fullfile(sPath,S(k).name);
    C{k} = imread(tmp);
end

Other comprehensive examples and explanations here:

http://www.mathworks.com/matlabcentral/answers/57446-faq-how-can-i-process-a-sequence-of-files

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

Related Solutions

MATLAB: Reference a cell array using a string to specify image data for imwrite

Simply put all of your cell arrays into one structure (or another cell array), and then you can trivially use indexing to access them:

S(1).images = {... cell array one ...}
S(2).images = {... cell array two ...}
...
S(N).images = {... cell array  N  ...}

then to access them you just need basic indexing:

for k = 1:numel(S)
    tmp = S(k).images;
    ... something with tmp
end

Note that it is better to use fullfile rather than string concatenation:

folder = fullfile(pwd,num2str(i),'Occlude');

MATLAB: I am getting the error while reading the images

Evidently the length is zero and so when you try to access index 1, it says "Index exceeds matrix dimensions." Try this more robust way:

if length(files_p) > 0
    fullFileName = fullfile(ipDir, files_p(1).name);
    tmp1=imread(fullFileName);
end

Best Answer

Related Solutions

MATLAB: Reference a cell array using a string to specify image data for imwrite

MATLAB: I am getting the error while reading the images

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