BPMB: BayesCNNs with perturbed multi-branch structure for robust facial expression recognition

Abstract

Wild Facial Expression Recognition (FER) task has been a long-standing challenge due to the various forms of uncertainty exist in expression data. When expression data is fed into a convolutional neural network (CNN), the model's estimated parameters also become uncertain. This uncertainty gives rise to concerns regarding the reliability of the recognition results. To quantify these uncertainties and achieve robust performance in the presence of noisy data, this paper introduces a novel model for Wild Facial Expression Recognition: the Bayesian Convolutional Neural Network with Perturbed Multi-Branch Structure (BPMB). This model aims to address uncertainty issues, enabling the network's decisions to become more deterministic with increasing training accuracy. Specifically, BPMB incorporates variational inference (VI) to introduce a probability distribution for the weights. A variational approximation to the true posterior is derived using Bayes by Backprop, involving two convolution operations: one for classification and another for quantifying uncertainty. Furthermore, an exploration is conducted into a lightweight multi-branch structure that leverages Dropout as a random generator to introduce perturbations during the training process, enhancing the model's robustness while extracting deep features. Extensive experiments validate the superiority of the proposed BPMB algorithm over the majority of existing mainstream algorithms on three widely utilized wild datasets.