The level sets of neural networks represent fundamental properties such as
decision boundaries of classifiers and are used to model non-linear manifold
data such as curves and surfaces. Thus, methods for controlling the neural
level sets could find many applications in machine learning.
In this paper we present a simple and scalable approach to directly control
level sets of a deep neural network. Our method consists of two parts: (i)
sampling of the neural level sets, and (ii) relating the samples' positions to
the network parameters. The latter is achieved by a sample network that is
constructed by adding a single fixed linear layer to the original network. In
turn, the sample network can be used to incorporate the level set samples into
a loss function of interest.
We have tested our method on three different learning tasks: improving
generalization to unseen data, training networks robust to adversarial attacks,
and curve and surface reconstruction from point clouds. For surface
reconstruction, we produce high fidelity surfaces directly from raw 3D point
clouds. When training small to medium networks to be robust to adversarial
attacks we obtain robust accuracy comparable to state-of-the-art methods.