Unexpected image size: All images must have the same size.

Andre-Brandao · Jun 1, 2021 · 2.1K views
Question
Hi, I'm having some problems with a bench of chest xray images. I tryed to use the code from the link below, but it did not work.   https://www.mathworks.com/matlabcentral/answers/385472-error-in-image-size   Error using trainNetwork (line 165)   Unexpected image size: All images must have the same size.   Error in chestXray1 (line 49)   net = trainNetwork(imdsTrain,layers,options);     inputSize = [224 224 1]; numClasses = 2; layers = [ imageInputLayer(inputSize) convolution2dLayer(5,20) batchNormalizationLayer reluLayer fullyConnectedLayer(numClasses) softmaxLayer classificationLayer]; options = trainingOptions('sgdm', ... 'MaxEpochs',3, ... 'ValidationData',imdsValidation, ... 'ValidationFrequency',30, ... 'Verbose',false, ... 'Plots','training-progress'); net = trainNetwork(imdsTrain,layers,options);  
Expert Answer
Profile picture of Kshitij Singh
Kshitij Singh PhD Expert
Answered Aug 14, 2026
You can use augmentedImageDataStore to resize all images to same size.
 
Use the following code for your problem:
 
dataChest = fullfile('/Users/andrebr4/Documents/MATLAB/chestXray/chest_xray');
imds = imageDatastore(dataChest, ...
    'IncludeSubfolders',true, ...
    'LabelSource','foldernames');

%%  Dividir o conjunto de dados em cada categoria
numTrainingFiles = 750;
[imdsTrain,imdsValidation] = splitEachLabel(imds,numTrainingFiles,'randomize');


%%%%%%%code for resizing
inputSize=[224 224 1];
imdsTrain=augmentedImageDatastore(inputSize, imdsTrain,'ColorPreprocessing','rgb2gray');

imdsValidation=augmentedImageDatastore(inputSize, imdsValidation,'ColorPreprocessing','rgb2gray');



%%  Configurar a rede neural
inputSize = [224 224 1];
numClasses = 2;

layers = [
    imageInputLayer(inputSize)
    convolution2dLayer(5,20)
    batchNormalizationLayer
    reluLayer
    fullyConnectedLayer(numClasses)
    softmaxLayer
    classificationLayer];

%%  Opções de treino
options = trainingOptions('sgdm', ...
    'MaxEpochs',5, ...
    'ValidationData',imdsValidation, ...
    'ValidationFrequency',30, ...
    'Verbose',false, ...
    'Plots','training-progress');

%% Treinar a rede neural
net = trainNetwork(imdsTrain,layers,options);

%%  Executar rede treinada no conjunto de teste
YPred = classify(net,imdsValidation);
YValidation = imdsValidation.Labels;

%% Calcular a precisão
accuracy = sum(YPred == YValidation)/numel(YValidation)
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