This blog aims to answer following questions.
How to read confusion matrix.
A confusion matrix is a technique for summarizing the performance of a classification algorithm.
This allows more detailed analysis than mere proportion of correct classifications accuracy.
A much better way to evaluate the performance of a classifier is to look at the confusion matrix.
What is confusion matrix and.
How to calculate confusion matrix for a 2 class classification problem.
A confusion matrix is a table that is often used to describe the performance of a classification model or classifier on a set of test data for which the true values are known.
The confusion matrix itself is relatively simple to understand but the related terminology can be confusing.
The general idea is to count the number of times instances of class a are classified as class b.
Confusion matrix will show you if your predictions match the reality and how do they math in more detail.
Now i see that twice the road was predicted to be a road.
If i want to read the result of predicting whether something is a road i look at the first row because the true label of the first row is road.
The labels are in the same order as the order of parameters in the labels argument of the confusion matrix function.
True positives true negatives false negatives and false positives.
The confusion matrix below shows predicted versus actual values and gives names to classification pairs.
What the confusion matrix is and why you need it.
For example to know the number of times the classifier confused images of 5s with 3s you would look in the 5th row and 3rd column of the confusion.
In predictive analytics a table of confusion sometimes also called a confusion matrix is a table with two rows and two columns that reports the number of false positives false negatives true positives and true negatives.
Confusion matrix is a performance measurement for machine learning classification.
Calculating a confusion matrix can give you a better idea of what your classification model.