Data Augmentation in Emotion Classification Using Generative Adversarial Networks
This addresses the problem of imbalanced label distribution in emotion classification for computer vision applications, representing an incremental improvement.
The paper tackles emotion classification with imbalanced datasets by proposing a GAN-based data augmentation method using CycleGAN with least-squared loss, achieving a 5-10% increase in classification accuracy on three benchmark datasets.
It is a difficult task to classify images with multiple class labels using only a small number of labeled examples, especially when the label (class) distribution is imbalanced. Emotion classification is such an example of imbalanced label distribution, because some classes of emotions like \emph{disgusted} are relatively rare comparing to other labels like {\it happy or sad}. In this paper, we propose a data augmentation method using generative adversarial networks (GAN). It can complement and complete the data manifold and find better margins between neighboring classes. Specifically, we design a framework with a CNN model as the classifier and a cycle-consistent adversarial networks (CycleGAN) as the generator. In order to avoid gradient vanishing problem, we employ the least-squared loss as adversarial loss. We also propose several evaluation methods on three benchmark datasets to validate GAN's performance. Empirical results show that we can obtain 5%~10% increase in the classification accuracy after employing the GAN-based data augmentation techniques.