Stochastic Downsampling for Cost-Adjustable Inference and
Improved Regularization in Convolutional Networks
Abstract
It is desirable to train convolutional networks (CNNs) to
run more efficiently during inference. In many cases however, the computational budget that the system has for inference cannot be known beforehand during training, or
the inference budget is dependent on the changing real-time
resource availability. Thus, it is inadequate to train just
inference-efficient CNNs, whose inference costs are not adjustable and cannot adapt to varied inference budgets. We
propose a novel approach for cost-adjustable inference in
CNNs - Stochastic Downsampling Point (SDPoint). During
training, SDPoint applies feature map downsampling to a
random point in the layer hierarchy, with a random downsampling ratio. The different stochastic downsampling con-
figurations known as SDPoint instances (of the same model)
have computational costs different from each other, while
being trained to minimize the same prediction loss. Sharing network parameters across different instances provides
significant regularization boost. During inference, one may
handpick a SDPoint instance that best fits the inference budget. The effectiveness of SDPoint, as both a cost-adjustable
inference approach and a regularizer, is validated through
extensive experiments on image classification