Real-time discriminant analysis in the presence of label and measurement noise

Vranckx, Iwein; Raymaekers, Jakob; De Ketelaere, Bart; Rousseeuw, Peter J.; Hubert, Mia

doi:10.1016/J.CHEMOLAB.2020.104197

Title

Real-time discriminant analysis in the presence of label and measurement noise

Author

Vranckx, Iwein

Raymaekers, Jakob

De Ketelaere, Bart

Rousseeuw, Peter J.

Hubert, Mia

Abstract

Quadratic discriminant analysis (QDA) is a widely used classification technique. Based on a training dataset, each class in the data is characterized by an estimate of its center and shape, which can then be used to assign unseen observations to one of the classes. The traditional QDA rule relies on the empirical mean and covariance matrix. Unfortunately, these estimators are sensitive to label and measurement noise which often impairs the model’s predictive ability. Robust estimators of location and scatter are resistant to this type of contamination. However, they have a prohibitive computational cost for large scale industrial experiments. We present a novel QDA method based on a recent real-time robust algorithm. We additionally integrate an anomaly detection step to classify the most atypical observations into a separate class of outliers. Finally, we introduce the label bias plot, a graphical display to identify label and measurement noise in the training data. The performance of the proposed approach is illustrated in a simulation study with huge datasets, and on real datasets about diabetes and fruit.

Language

English

Source (journal)

Chemometrics and intelligent laboratory systems. - Amsterdam, 1986, currens

Publication

Amsterdam : 2021

ISSN

0169-7439 [print]

1873-3239 [online]

DOI

10.1016/J.CHEMOLAB.2020.104197

Volume/pages