How to calculate the accuracy of the classifier ? and show the confusion matrix.

Question

Munshida P 2020-1-28

0
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https://ww2.mathworks.cn/matlabcentral/answers/502331-how-to-calculate-the-accuracy-of-the-classifier-and-show-the-confusion-matrix

回答： Hitham 2020-9-25

I had implemented a simple face recognition code. how to calculate its accuracy? and how to plot the confusion matrix .

clc
clear
% Load Image dataset
faceDatabase = imageSet('facedatabaseatt','recursive');
%splitting into training and testing sets
[training,test] = partition(faceDatabase,[0.8 0.2]);
% Extract HOG Features for training set 
featureCount = 1;
for i=1:size(training,2)
    for j = 1:training(i).Count
        trainingFeatures(featureCount,:) = extractHOGFeatures(read(training(i),j));
       % imshow(read(training(i),j));
        %pause(0.0011);
        trainingLabel{featureCount} = training(i).Description;    
        featureCount = featureCount + 1;
    end
    personIndex{i} = training(i).Description;
end
% Create 40 class classifier
faceClassifier = fitcknn(trainingFeatures,trainingLabel);
%testing
for person=1:40
    for j = 1:test(person).Count
        queryImage = read(test(person),j);
        queryFeatures = extractHOGFeatures(queryImage);
        actualLabel = predict(faceClassifier,queryFeatures) %actuallabel
        C=test(person).Description;                           % predictedlabel
        predictedLabel= cellstr(C)           %converting into cell array
        
    end
end
 