Online Knowledge Distillation by Temporal-Spatial Boosting

Online knowledge distillation (KD) mutually trains a group of student networks from scratch in a peer-teaching manner, eliminating the need for pre-trained teacher models. However, supervision from peers can be noisy, especially in the early stage of training. In this paper, we propose a novel method for online knowledge distillation by temporal-spatial boosting (TSB). The proposed method constructs superior "teachers" with two modules, temporal accumulator and spatial integrator. Specifically, the temporal accumulator leverages the previous outputs of networks during training and produces a representative prediction over all classes. Instead of merely imitating the outputs of other networks as in vanilla online KD, we further propose the so-called spatial integrator that consolidates the knowledge learned by all networks and yields a stronger instructor. The operations of these two modules are simple and straightforward, which can be computed efficiently on the fly during training. The proposed method can improve the efficiency of transferring effective knowledge as well as stabilize the training process. Experimental results on various benchmark datasets and network structures validate the effectiveness of the proposed method over the state-of-the-art.