how to loop through a folder

Hello

I have a folder containing 1000 images. I want to produce 10 random cropped images from each image in the folder and store them as original_file_name_crop1.png to original_file_name_crop10.png.I'm using the code below. How can I make it loop through all the images?

for j = 1:length(file_list)

    for i = 1:10
    originalImage = imread(fullfile(dir_in, file_list(j).name));

    inputSize = size(originalImage(:,:,1:3));
    targetSize = [128 128];

    rect = randomWindow2d(inputSize,targetSize);

    K = imcrop(originalImage(:,:,1:3), rect);
  
    filename = sprintf('cropped_image_%d.png', i);
    imwrite(K, fullfile(dir_out, filename));
    end
end

Answer 1

[Walter Roberson]

for j = 1:length(file_list)
    originalImage = imread(fullfile(dir_in, file_list(j).name));
    [this_folder, this_basename, this_ext] = fileparts(originalImage);
    
    for i = 1:10
        inputSize = size(originalImage(:,:,1:3));
        targetSize = [128 128];
    
        rect = randomWindow2d(inputSize,targetSize);
    
        K = imcrop(originalImage(:,:,1:3), rect);
      
        new_filename = fullfile(this_folder, this_basename + "_crop" + i + this_ext));
        imwrite(K, new_filename);
    end
end

Answer 2

[Image Analyst]

Try this:

% Optional initialization steps
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;

inputFolder = pwd; % Whatever.
outputFolder = fullfile(inputFolder, 'Cropped Output Images')
% outputFolder = inputFolder;
if ~isfolder(outputFolder)
    % Make output folder if it does not exist yet.
    mkdir(outputFolder);
end
filePattern = fullfile(inputFolder, '*.png');
fileList = dir(filePattern)
targetSize = [128, 128];
for k = 1:length(fileList)
    inputFullFileName = fullfile(inputFolder, fileList(k).name)
    originalImage = imread(inputFullFileName);
    subplot(1, 2, 1);
    imshow(originalImage);
    caption = sprintf('Image #%d of %d : %s', k, length(fileList), fileList(k).name)
    title(caption, 'Interpreter','none')
    inputSize = size(originalImage);
    
    % Skip images that are too small.
    if inputSize(1) < targetSize(1) || inputSize(2) < targetSize(2)
        fprintf('Skipping %s because it is too small.\n', fileList(k).name)
        continue;
    end
    
    % Make an output folder for the 10 image
    for k2 = 1 : 10
        % Create randomly located rectangle.
        rect = randomWindow2d(inputSize,targetSize);
        
        % Crop out that rectangle to its own image.
        croppedOutputImage = imcrop(originalImage, rect);
        subplot(1, 2, 2);
        imshow(croppedOutputImage);
        drawnow;
        
        % Get the output filename.
        [f, baseFileNameNoExt, etc] = fileparts(fileList(k).name);
        baseOutputFileName = sprintf('%s_crop_%2.2d.png', baseFileNameNoExt, k2);
        fullOutputFileName = fullfile(outputFolder, baseOutputFileName);
        % Save out the image to a folder for the 10 images.
        fprintf('      Saving "%s".\n', fullOutputFileName);
        imwrite(croppedOutputImage, fullOutputFileName);
    end
end

%=========================================================================
function rect = randomWindow2d(inputSize, targetSize)
rows = inputSize(1);
columns = inputSize(2);
topRow = randi(rows - targetSize(1));
leftCol = randi(columns - targetSize(2));
width = targetSize(2);
height = targetSize(1);
rect = [leftCol, topRow, width, height];
end