How to plot confusion matrix

7 次查看（过去 30 天）

bayoishola20 2014-10-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/159288-how-to-plot-confusion-matrix

评论： bayoishola20 2014-11-4

I have performed my image segmentation using kmeans but need to get the confusion matrix. My image segmentation matrix for six(6) classes has numbers 1 to 6 in it which is perfect. On getting my trained classes BW_1,BW_2,BW_3,BW_4,BW_5,BW_6 I have in each only one's(1's) and zero's(0's) but need to create a single confusion matrix like in this link http://www.mathworks.com/help/nnet/ref/plotconfusion.html?searchHighlight=confusion%2520matrix

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Greg Heath 2014-10-20

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/159288-how-to-plot-confusion-matrix#answer_155860

在 MATLAB Online 中打开

The function plotconfusion handles more than 2 classes. Replace the iris_dataset or simplecluster_dataset in the help and doc examples for plotconfusion

    [x,t]        = iris_dataset;
    net          = patternnet;
    rng('default')
    [net tr y e] = train(net,x,t);
    NMSE         = mse(e)/mean(var(t',1)) %0.0418
    R2           = 1-NMSE                 %0.9582
    plotconfusion(t,y);

Find the minimum number of hidden nodes that yields an acceptable result

Hope this helps.

Thank you for formally accepting my answer

Greg

3 个评论
显示 1更早的评论隐藏 1更早的评论

Greg Heath 2014-10-21

在 MATLAB Online 中打开

That command assumes the input and target matrices are combined as in the MATLAB example database

 help nndatasets
 doc nndatasets

If your data is not formatted that way, then change the command to read the way your data is formatted.

bayoishola20 2014-11-4

You said the command assumes that my input & target matrices are combined. please in the case where my target matrix are 6 different matrices and each contain only ones and zeros while the input has 1,2,3,4,5,6. How can I achieve this. Thanks in advance.

请先登录，再进行评论。

更多回答（1 个）

Star Strider 2014-10-20

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/159288-how-to-plot-confusion-matrix#answer_155808

编辑：Star Strider 2014-10-20

The Neural Network Toolbox confusion function will only let you plot (2x2) classification results. To plot more classes, use the Statistics Toolbox confusion function.

The crosstab function will give you the chi-squared statistic and the probability.

7 个评论
显示 5更早的评论隐藏 5更早的评论

Star Strider 2014-10-20

If you have vectors with your known and predicted classes, those are your inputs to your confusion matrix. I got the impression from your Question, specifically ‘My image segmentation matrix for six(6) classes has numbers 1 to 6 in it which is perfect.’ that you already had those and simply wanted to know how to create a confusion matrix for your 6 classes.

bayoishola20 2014-10-20

编辑：bayoishola20 2014-10-20

Exactly! But am I to combine the trained classes(known, with 0's and 1's) so I could have a single matrix like the predicted or use them as they are? If so, please how do I do that?

请先登录，再进行评论。

请先登录，再回答此问题。