Extracting data from confusion matrix fig

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Hi, How can i extract the data from a confusion matrix fig file?
  3 Comments
M Umair
M Umair on 26 May 2022
Hello Bala,
Thanks for your time.
The figure contains confusion matrix (file attached). I want to extract all numerical values presented in the figure excluding the percentages.
Thank you

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Answers (2)

Chunru
Chunru on 26 May 2022
Edited: Chunru on 26 May 2022
f = openfig('SqueezeNet-CM', 'visible');
h = findobj(f.Children(2).Children, 'Type', 'Text');
data = zeros(length(h), 1);
for i=1:length(h)
data(i) = sscanf(h(i).String, '%f');
end
m = 5;
data = reshape(data, [2*m m]);
data_number = data(4:2:end, 2:end)
data_number = 4×4
115 0 0 2 769 447 174 90 107 753 1020 681 209 0 6 427
data_number = data_number(end:-1:1, end:-1:1)
data_number = 4×4
427 6 0 209 681 1020 753 107 90 174 447 769 2 0 0 115

Bala Tripura Bodapati
Bala Tripura Bodapati on 26 May 2022
Hi Umair,
It is my understanding that you would like to extract the numeric values from confusion matrix plotted on a figure.
From the confusion matrix plotted using 'plotconfusion' function, there is no method to extract the numeric values.
Alternatively, you can plot the confusion matrix using the 'confusionchart' function on a figure and then extract the numeric values.
The following code illustrates the same:
load fisheriris
X = meas;
Y = species;
Mdl = fitcknn(X,Y,'NumNeighbors',5,'Standardize',1);
predictedY = resubPredict(Mdl);
fig=figure;
confusionchart(Y,predictedY);
'cm' is a confusion chart object. The 'NormalizedValues' property of this object outputs the numeric matrix:
matrix=cm.NormalizedValues
Refer the Matrices documentation for more information on accessing elements from a matrix.
Also, refer the confusionchart documentation for more information on confusion chart and graphics hierarchy documentation for more information on accessing figure object and it's children.

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