DE-DFKD: diversity enhancing data-free knowledge distillation

Data-Free Knowledge Distillation (DFKD) can be used to train students using synthetic data, when the original dataset of the teacher network is not accessible. However, existing studies mainly focus on how to use the prior knowledge of the teacher network to synthesize data, ignoring the lack of diversity of synthesized data, which leads to the inability of the student network to learn the real data distribution and low robustness. In this paper, we propose a Diversity-Enhanced Data-Free Knowledge Distillation (DE-DFKD) method based on the idea of generative image modelling, which introduces conditional generative networks and metric learning to solve the problem of class imbalance and single intra-class data distribution in synthetic datasets. The experimental results show that DE-DFKD synthesizes better quality data on MNIST, CIFAR-10, and CIFAR-100 datasets with Frechet Inception Distance (FID) values of 51.79, 60.25, and 50.1, respectively, and higher accuracy of student networks compared with existing schemes.