State-of-the-art techniques for enhancing robustness of deep networks mostly
rely on empirical risk minimization with suitable data augmentation. In this
paper, we propose a complementary approach motivated by communication theory,
aimed at enhancing the signal-to-noise ratio at the output of a neural network
layer via neural competition during learning and inference. In addition to
minimization of a standard end-to-end cost, neurons compete to sparsely
represent layer inputs by maximization of a tilted exponential (TEXP) objective
function for the layer. TEXP learning can be interpreted as maximum likelihood
estimation of matched filters under a Gaussian model for data noise. Inference
in a TEXP layer is accomplished by replacing batch norm by a tilted softmax,
which can be interpreted as computation of posterior probabilities for the
competing signaling hypotheses represented by each neuron. After providing
insights via simplified models, we show, by experimentation on standard image
datasets, that TEXP learning and inference enhances robustness against noise
and other common corruptions, without requiring data augmentation. Further
cumulative gains in robustness against this array of distortions can be
obtained by appropriately combining TEXP with data augmentation techniques