An Energy-Based Framework for Arbitrary Label Noise Correction
Authors: Jaspreet Sahota, Divya Shanmugam, Janahan Ramanan, Sepehr Eghbali, Marcus Brubaker
Keywords: label noise, feature dependent noise, label correction, unsupervised machine learning, semi-supervised machine learning
TL;DR: We show how to learn a discriminative representation using an energy based semi-supervised model and we show how to use it to correct input dependent label noise of various types on several datasets.
Abstract: We propose an energy-based framework for correcting mislabelled training examples in the context of binary classification. While existing work addresses random and class-dependent label noise, we focus on feature dependent label noise, which is ubiquitous in real-world data and difficult to model. Two elements distinguish our approach from others: 1) instead of relying on the original feature space, we employ an autoencoder to learn a discriminative representation and 2) we introduce an energy-based formalism for the label correction problem. We prove that a discriminative representation can be learned by training a generative model using a loss function comprised of the difference of energies corresponding to each class. The learned energy value for each training instance is compared to the original training labels and contradictions between energy assignment and training label are used to correct labels. We validate our method across eight datasets, spanning synthetic and realistic settings, and demonstrate the technique's state-of-the-art label correction performance. Furthermore, we derive analytical expressions to show the effect of label noise on the gradients of empirical risk.