Error using Semantic Segmentation Using Deep Learning

I was trying to replicate the example in Semantic Segmentation Using Deep Learning

(https://nl.mathworks.com/help/vision/examples/semantic-segmentation-using-deep-learning.html), and I got this error.

Error using matlab.io.datastore.PixelLabelDatastore.label2cat (line 1030)

Pixel label image has RGB-triplet pixel label IDs instead of scalar pixel label IDs.

At first I got it at

pximds = pixelLabelImageDatastore(imdsTrain,pxdsTrain, ...

'DataAugmentation',augmenter);

But then I didn't include the augmenter and there was no problem there. Afterwards, the same again in:

[net, info] = trainNetwork(pximds,lgraph,options);

I searched it in google, it seems other people also had the same, but there was no answer to it. It's just the example proposed in mathworks

Answer 1

[Sourav Bairagya]

I have tried to replicate that same example (mentioned in the provided link) on MATLAB R2019b and it sucessfully ran.

On MATLAB 2019a, "deeplabv3plusLayers" function is not available. Here I have ran the same example using U-Net and it sucessfully ran.

% Create U-Net
lgraph = unetLayers(imageSize, numClasses);

imageFreq = tbl.PixelCount ./ tbl.ImagePixelCount;
classWeights = median(imageFreq) ./ imageFreq;

pxLayer = pixelClassificationLayer('Name','labels','Classes',tbl.Name,'ClassWeights',classWeights);
lgraph = replaceLayer(lgraph,"Segmentation-Layer",pxLayer);

The above mentioned errors have not been produced in any of the cases.

Answer 2

[Vasilis Giannoglou]

If I copy-paste all the commands in a seperate .m file, I get the above errors. If I open the

openExample('deeplearning_shared/SemanticSegmentationUsingDeepLearningExample')

then it runs ok. I really don't know why