I want to read the images from multiple sub-folders, kindly help

Here is the code which reads images from one folder. but I want to read images from multiple sub-folders. I am new to MATLAB, kindly help me by editing my code

myDir = 'Training\0\';

dd = dir([myDir '*.jpg']);
%%Initilizing the variable for fast loading
trainSet = uint8(zeros(48*48,length(dd)));

for i=1:length(dd)
    %%reading the  images
    img = imread([myDir dd(1).name]);
    %%now storing it into one variable
    trainSet(:,i) = img(:);

end

[Rik]

What is your matlab release and what is your folder structure with the files you want to read? (since R2016b you can use a double * in dir to search in multiple folders recursively)

[saeeda saher]

My MATLAB release is R2015b and i want to read . jpg files from directory

[Walter Roberson]

We only see one directory in your code. What are the other directories? Should we assume that you want to process all of the directories under Training?

[saeeda saher]

Training is the folder which has sub folders 0,1,2,3,4,5,6 and these sub folders have images of .jpg format

[Rik]

Does my answer now work for you? If not, what are your further problems? If it does, please accept it.

[saeeda saher]

If you edit my code, it will be more helpful for me to learn from you, I tried but its processing one folder 0 and then prompts errors.

[Rik]

The code I wrote (or actually adapted from Image Analyst) replaces the line with dir. Just replace dd with totalFileList and dd(1).name with totalFileList{i}. (that last one is also a bug in your code: it only loads the first file, but does so repeatedly)

So now my question is, what code are you running and what specific errors are you getting?

[saeeda saher]

 *Where I am making mistakes?? kindly correct it*
 % Define a starting folder.
  start_path = 'C:\Users\saeeda\Desktop\Training';
  % Ask user to confirm or change.
  topLevelFolder = start_path;
  if topLevelFolder == 0
    return;
  end
  % Get list of all subfolders.
  allSubFolders = genpath(topLevelFolder);
  % Parse into a cell array.
  remain = allSubFolders;
  listOfFolderNames = {};
  while true
    [singleSubFolder, remain] = strtok(remain, ';');%#ok (suppres m-lint warning)
    if isempty(singleSubFolder)
      break;
    end
    listOfFolderNames = [listOfFolderNames singleSubFolder];%#ok (suppres m-lint warning)
  end
  numberOfFolders = length(listOfFolderNames);
  totalFileList={};%this will contain all file names of jpg files
  % Process all image files in those folders.
  for k = 1 : numberOfFolders
    % Get this folder and print it out.
    thisFolder = listOfFolderNames{k};
    %fprintf('Processing folder %s\n', thisFolder);
    
    % Get JPG files.
    filePattern = sprintf('%s/*.jpg', thisFolder);
    baseFileNames = dir(filePattern);
    numberOfImageFiles = length(baseFileNames);
    % Now we have a list of all files in this folder.
    %%Initilizing the variable for fast loading
  trainSet = uint8(zeros(48*48,length(totalFileList)));
      for i = 1 :length(totalFileList)

    img = fullfile(totalFileList, totalFileList{i});
             trainSet(:,i) = img(:);
      end

[Rik]

You removed some code. If you try to merge code, you need to make sure to understand what the code is doing. Your pre-allocation is now inside a loop, which is never good idea.

% Define a starting folder.
start_path = 'C:\Users\saeeda\Desktop\Training';
% Ask user to confirm or change.
topLevelFolder = start_path;
if topLevelFolder == 0
    return;
end
% Get list of all subfolders.
allSubFolders = genpath(topLevelFolder);
% Parse into a cell array.
remain = allSubFolders;
listOfFolderNames = {};
while true
    [singleSubFolder, remain] = strtok(remain, ';');%#ok (suppres m-lint warning)
    if isempty(singleSubFolder)
        break;
    end
    listOfFolderNames = [listOfFolderNames singleSubFolder];%#ok (suppres m-lint warning)
end
numberOfFolders = length(listOfFolderNames);
totalFileList={};%this will contain all file names of jpg files
% Process all image files in those folders.
for k = 1 : numberOfFolders
    % Get this folder and print it out.
    thisFolder = listOfFolderNames{k};
    %fprintf('Processing folder %s\n', thisFolder);

      % Get JPG files.
      filePattern = sprintf('%s/*.jpg', thisFolder);
      baseFileNames = dir(filePattern);
      numberOfImageFiles = length(baseFileNames);
      % Now we have a list of all files in this folder.

      if numberOfImageFiles >= 1
          % Go through all those image files.
          for f = 1 : numberOfImageFiles
              fullFileName = fullfile(thisFolder, baseFileNames(f).name);
              totalFileList{end+1}=fullFileName;%#ok (suppres m-lint warning)
              %fprintf('     Processing image file %s\n', fullFileName);
          end
      else
          %fprintf('     Folder %s has no image files in it.\n', thisFolder);
      end
  end

% Initilizing the variable for fast loading
trainSet = uint8(zeros(48*48,length(totalFileList)));
for i = 1 :length(totalFileList)
    img = fullfile(totalFileList, totalFileList{i});
    trainSet(:,i) = img(:);
end

[saeeda saher]

I am getting this error

Conversion to uint8 from cell is not possible.

Error in programm (line 47)
    trainSet(:,i) = img(:);

Answer 1

[Rik]

Image analyst has written a function that can do this, see this answer and its attachment.

[saeeda saher]

I tried it already but i do not understand how to put my code in it, will you kindly edit my code??

[Rik]

These are really minimal edits. You really should be able to do this yourself, especially with code that has this many comment explaining what it is doing.

% Define a starting folder.
start_path = 'Training\';
% Ask user to confirm or change.
topLevelFolder = start_path;
if topLevelFolder == 0
  return;
end
% Get list of all subfolders.
allSubFolders = genpath(topLevelFolder);
% Parse into a cell array.
remain = allSubFolders;
listOfFolderNames = {};
while true
  [singleSubFolder, remain] = strtok(remain, ';');%#ok (suppres m-lint warning)
  if isempty(singleSubFolder)
    break;
  end
  listOfFolderNames = [listOfFolderNames singleSubFolder];%#ok (suppres m-lint warning)
end
numberOfFolders = length(listOfFolderNames);

totalFileList={};%this will contain all file names of jpg files
% Process all image files in those folders.
for k = 1 : numberOfFolders
  % Get this folder and print it out.
  thisFolder = listOfFolderNames{k};
  %fprintf('Processing folder %s\n', thisFolder);
  
  % Get JPG files.
  filePattern = sprintf('%s/*.jpg', thisFolder);
  baseFileNames = dir(filePattern);
  numberOfImageFiles = length(baseFileNames);
  % Now we have a list of all files in this folder.
  
  if numberOfImageFiles >= 1
    % Go through all those image files.
    for f = 1 : numberOfImageFiles
      fullFileName = fullfile(thisFolder, baseFileNames(f).name);
            totalFileList{end+1}=fullFileName;%#ok (suppres m-lint warning)
      %fprintf('     Processing image file %s\n', fullFileName);
    end
  else
    %fprintf('     Folder %s has no image files in it.\n', thisFolder);
  end
end