cGANs with Auxiliary Discriminative Classifier

Conditional generative models aim to learn the underlying joint distribution of data and labels, and thus realize conditional generation. Among them, auxiliary classifier generative adversarial networks (AC-GAN) have been widely used, but suffer from the issue of low intra-class diversity on generated samples. In this paper, we point out that the fundamental reason is that the classifier of AC-GAN is generator-agnostic, and thus cannot provide informative guidance to the generator to approximate the target joint distribution, leading to a minimization of conditional entropy that decreases the intra-class diversity. Based on this finding, we propose novel cGANs with auxiliary discriminative classifier (ADC-GAN) to address the issue of AC-GAN. Specifically, the auxiliary discriminative classifier becomes generator-aware by distinguishing between the real and fake data while recognizing their labels. We then optimize the generator based on the auxiliary classifier along with the original discriminator to match the joint and marginal distributions of the generated samples with those of the real samples. We provide theoretical analysis and empirical evidence on synthetic and real-world datasets to demonstrate the superiority of the proposed ADC-GAN compared to competitive cGANs.