SVM is not always confident: Telling whether the output from multiclass SVM is true or false by analysing its confidence values

This paper presents an algorithm to distinguish whether the output label that is yielded from multiclass support vector machine (SVM) is true or false without knowing the answer. Such judgment is done only by the confidence analysis based on the pre-training/testing using the training data. Such true/false judgment is useful for refining the output labels. We experimentally demonstrate that the decision value difference between the top candidate and the second candidate is a good measure. In addition, a proper threshold can be determined by the pre-training/testing using only the training data. Experimental results using three standard image datasets demonstrate that our proposed algorithm can improve Matthews correlation coefficient (MCC) much better than simply thresholding the decision value for the top candidate.