how to overcome the following error? errors are described in the comment

clear all; close all; clc; %deviceInfo = gpuDevice;
rootFolder = fullfile('E:\education\Matlab\bin\Endoscopy\', '101_ObjectCategories'); categories = {'airplanes', 'ferry', 'laptop'};
imds = imageDatastore(fullfile(rootFolder, categories), 'LabelSource', 'foldernames');
tbl = countEachLabel(imds) minSetCount = min(tbl{:,2}); % determine the smallest amount of images in a category
% Use splitEachLabel method to trim the set. imds = splitEachLabel(imds, minSetCount, 'randomize');
% Notice that each set now has exactly the same number of images. countEachLabel(imds)
% Find the first instance of an image for each category airplanes = find(imds.Labels == 'airplanes', 1); ferry = find(imds.Labels == 'ferry', 1); laptop = find(imds.Labels == 'laptop', 1); figure subplot(1,3,1); imshow(readimage(imds,airplanes)) subplot(1,3,2); imshow(readimage(imds,ferry)) subplot(1,3,3); imshow(readimage(imds,laptop))
% Load pre-trained AlexNet net = alexnet() net.Layers
net.Layers(1)
net.Layers(end) % Number of class names for ImageNet classification task numel(net.Layers(end).ClassNames)
imds.ReadFcn = @(filename)readAndPreprocessImage(filename); %% function Iout = readAndPreprocessImage(filename) I = imread(filename); % Some images may be grayscale. Replicate the image 3 times to % create an RGB image. if ismatrix(I) I = cat(3,I,I,I); end % Resize the image as required for the CNN. Iout = imresize(I, [227 227]); % Note that the aspect ratio is not preserved. In Caltech 101, the % object of interest is centered in the image and occupies a % majority of the image scene. Therefore, preserving the aspect % ratio is not critical. However, for other data sets, it may prove % beneficial to preserve the aspect ratio of the original image % when resizing. end %% [trainingSet, testSet] = splitEachLabel(imds, 0.3, 'randomize'); %%
% Get the network weights for the second convolutional layer w1 = net.Layers(2).Weights;
% Scale and resize the weights for visualization w1 = mat2gray(w1); w1 = imresize(w1,5);
% Display a montage of network weights. There are 96 individual sets of % weights in the first layer. figure montage(w1) title('First convolutional layer weights') %% featureLayer = 'fc7'; %% trainingFeatures = activations(net, trainingSet, featureLayer, ... 'MiniBatchSize', 32, 'OutputAs', 'columns','ExecutionEnvironment','cpu'); %% trainingLabels = trainingSet.Labels;
% Train multiclass SVM classifier using a fast linear solver, and set % 'ObservationsIn' to 'columns' to match the arrangement used for training % features. classifier = fitcecoc(trainingFeatures, trainingLabels, ... 'Learners', 'Linear', 'Coding', 'onevsall', 'ObservationsIn', 'columns');

[John D'Errico]

Please don't answer your own question just to add some information. In general, don't answer your own question at all. Worse, then you accepted what was not an answer to your question at all. I've moved the error message into this comment:

Error using matlab.io.datastore.ImageDatastore/readimage (line 32) Error using ReadFcn @(filename)readAndPreprocessImage(filename) function handle for file E:\education\Matlab\bin\Endoscopy\101_ObjectCategories\airplanes\image_0136.jpg.

Undefined function 'readAndPreprocessImage' for input arguments of type 'char'.

Error in @(filename)readAndPreprocessImage(filename)

Error in nnet.internal.cnn.ImageDatastoreDispatcher (line 120) [this.ExampleImage, exampleInfo] = imageDatastore.readimage(1);

Error in nnet.internal.cnn.DataDispatcherFactory>iCreateImageDatastoreDispatcher (line 64) dispatcher = nnet.internal.cnn.ImageDatastoreDispatcher( inputs, miniBatchSize, endOfEpoch, precision );

Error in nnet.internal.cnn.DataDispatcherFactory.createDataDispatcher (line 32) dispatcher = iCreateImageDatastoreDispatcher( inputs, miniBatchSize, endOfEpoch, precision );

Error in SeriesNetwork>iDataDispatcher (line 522) dispatcher = nnet.internal.cnn.DataDispatcherFactory.createDataDispatcher( ...

Error in SeriesNetwork/activations (line 343) dispatcher = iDataDispatcher( X, miniBatchSize, precision );

[Joss Knight]

Why should we be expected to read and interpret this mishmash of unformatted code? MATLAB Answers can do MATLAB syntax highlighting. Can you use it?

[John D'Errico]

Joss has a valid point. Read and use what you find here:

https://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup#answer_18099

[Aman Swaraj]

can anyone answer his question though? I'm having similar error:

Error using matlab.io.datastore.ImageDatastore/readimage (line 36)
Error using ReadFcn @(filename)readAndPreprocessImage(filename) function handle for file
E:\IndianCulturalEventRecognition\1\1.jpg.

Undefined function 'readAndPreprocessImage' for input arguments of type 'char'.

Error in CNN_main>@(filename)readAndPreprocessImage(filename)

[Walter Roberson]

Did you install https://www.mathworks.com/matlabcentral/fileexchange/57116-deep-learning-for-computer-vision-demo-code ?