Interpretability in Convolutional Neural Networks for Building Damage
Classification in Satellite Imagery
- Thomas Y. Chen
Abstract
Natural disasters ravage the world's cities, valleys, and shores on a
monthly basis. Having precise and efficient mechanisms for assessing
infrastructure damage is essential to channel resources and minimize the
loss of life. Using a dataset that includes labeled pre- and post-
disaster satellite imagery, the xBD dataset, we train multiple
convolutional neural networks to assess building damage on a
per-building basis. In order to investigate how to best classify
building damage, we present a highly interpretable deep-learning
methodology that seeks to explicitly convey the most useful information
required to train an accurate classification model. We also delve into
which loss functions best optimize these models. Our findings include
that ordinal-cross entropy loss is the most optimal loss function to use
and that including the type of disaster that caused the damage in
combination with a pre- and post-disaster image best predicts the level
of damage caused. We also make progress in the realm of qualitative
representations of which parts of the images that the model is using to
predict damage levels, through gradient class-activation maps. Our
research seeks to computationally contribute to aiding in this ongoing
and growing humanitarian crisis, heightened by climate change.
Specifically, it advances the study of more interpretable machine
learning models, which were lacking in previous literature and are
important for the understanding of not only research scientists but also
operators of such technologies in underserved regions.