Reading an image sequence: "Error: The filename or url argument must be a string."

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Hello, I'm trying to work over a sequence of images, I have used dir to obtain a list of all the files:
dirData = dir([dirName, '\*.png']); %# Get the data for the current directory
dirIndex = [dirData.isdir]; %# Find the index for directories
fileList = {dirData(~dirIndex).name}'; %'# Get a list of the files
if ~isempty(fileList)
imgList = cellfun(@(x) fullfile(dirName,x),... %# Prepend path to files
fileList,'UniformOutput',false);
end
imgst=cellstr(imgList);
I tried looping over the list but I got an error so I then tried imread over only one member of the array: imread(imgst(1))
and again I got the error saying argument wasn't a string.
I thought cellstr would convert the members in the list to strings? If they're not strings what are they? how can I reference each file in my list so I can work with them over a loop? I know similar questions have been asked before but I didn't find an answer for an error like mine.
Thanks a lot
  1 Comment
Walter Roberson
Walter Roberson on 8 Jul 2020
The line
imgList = cellfun(@(x) fullfile(dirName,x),... %# Prepend path to files
fileList,'UniformOutput',false);
can be replaced with
imgList = fullfile(dirName, fileList);
fullfile() is happy to take a cell array of character vectors as the second argument.

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Answers (3)

Fer
Fer on 4 Oct 2015
Okay, so I found the answer to my own question. Not deleting in case someone has the same problem. The only thing I had to so was calling
imread(imgst{1})
so basically just using {} instead of ().
I had not used cells before so, my bad.
  2 Comments
Nathaniel Conrad
Nathaniel Conrad on 8 Jul 2020
Thank you for pointing this out! I was using a cell data container to hold a string character for a file path for the first time and having the same issue, too.
I do find it odd that if a cell only has one element in it, then you must index the container variable with {1} in order to extract the string that is labeling the relevant image file path.
For example, if you store the string in a structure array, then you don't need to index the structure array data container variable at all. Weird!

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Tess Meier
Tess Meier on 22 Jan 2019
Yes thank you!!!!!!

hossam mahmoud
hossam mahmoud on 7 Feb 2021
I found the solution
just try this
s=convertStringsToChars(s);

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