I can't to find image SMOTE coding.

I have some experimet for image classification and I want to generate new data by SMOTE but I can't to find about image SMOT coding. Can you suggest me about the code.

Answer 1

[Neha]

Hi,

I understand that you want to implement SMOTE for image classification. You can refer to the following File Exchange submission to download the file containing the implementation of the 'smote' function:

https://www.mathworks.com/matlabcentral/fileexchange/75401-synthetic-minority-over-sampling-technique-smote

Since SMOTE typically operates on numerical feature vectors, the first step involves converting images into a suitable format. After generating synthetic samples, you'll need to convert these back into images and handle them appropriately for your classification task. Please refer to the following code snippet which implements SMOTE for the Digits dataset using the code provided in the File Exchange submission.

dataFolder = fullfile(toolboxdir('nnet'),'nndemos','nndatasets','DigitDataset');
imds = imageDatastore(dataFolder, ...
    'IncludeSubfolders',true,'LabelSource','foldernames');
allFeatures = []; 
allLabels = []; 

while hasdata(imds)
    [img, info] = read(imds);
    label = info.Label; 
    
    featureVector = double(reshape(img, [], 1));
    
    allFeatures = [allFeatures; featureVector'];
    allLabels = [allLabels; label];
end

% Convert labels to numeric if they're categorical
if iscell(allLabels)
    [~, ~, allLabels] = unique(allLabels);
end

% Use SMOTE to oversample all classes 100% (using default 5 k-nearest neighbors)
[smoteFeatures, smoteLabels] = smote(allFeatures, 0.5, 'Class', allLabels);

%% 
imageSize = [28, 28];
numImages = size(smoteFeatures, 1);
syntheticImages = reshape(smoteFeatures', [imageSize, 1, numImages]);
outputFolder = '<path to syntheticImages>'; % Define where to save images
if ~exist(outputFolder, 'dir')
    mkdir(outputFolder); 
end

numImages = size(syntheticImages, 4);
for i = 1:numImages
    img = syntheticImages(:, :, :, i); % Extract the i-th image
    label = smoteLabels(i);
    filename = sprintf('%s_%d.png', label, i); 
    fullPath = fullfile(outputFolder, filename);
    imwrite(img, fullPath);
end

syntheticImds = imageDatastore(outputFolder, 'Labels', smoteLabels);

Hope this helps!