Deeply Shared Filter Bases for Parameter-Efficient Convolutional Neural Networks
This work addresses parameter efficiency for deep learning practitioners, offering a method that improves representation capability without performance degradation, though it is incremental in the context of existing parameter-sharing approaches.
The paper tackles the problem of parameter inefficiency in convolutional neural networks by proposing a recursive convolution block design with orthogonality regularization to control vanishing/exploding gradients, achieving performance improvements without trading off accuracy while significantly reducing parameters.
Modern convolutional neural networks (CNNs) have massive identical convolution blocks, and, hence, recursive sharing of parameters across these blocks has been proposed to reduce the amount of parameters. However, naive sharing of parameters poses many challenges such as limited representational power and the vanishing/exploding gradients problem of recursively shared parameters. In this paper, we present a recursive convolution block design and training method, in which a recursively shareable part, or a filter basis, is separated and learned while effectively avoiding the vanishing/exploding gradients problem during training. We show that the unwieldy vanishing/exploding gradients problem can be controlled by enforcing the elements of the filter basis orthonormal, and empirically demonstrate that the proposed orthogonality regularization improves the flow of gradients during training. Experimental results on image classification and object detection show that our approach, unlike previous parameter-sharing approaches, does not trade performance to save parameters and consistently outperforms overparameterized counterpart networks. This superior performance demonstrates that the proposed recursive convolution block design and the orthogonality regularization not only prevent performance degradation, but also consistently improve the representation capability while a significant amount of parameters are recursively shared.