  As an important data selection schema, active learning emerges as the
essential component when iterating an Artificial Intelligence (AI) model. It
becomes even more critical given the dominance of deep neural network based
models, which are composed of a large number of parameters and data hungry, in
application. Despite its indispensable role for developing AI models, research
on active learning is not as intensive as other research directions. In this
paper, we present a review of active learning through deep active learning
approaches from the following perspectives: 1) technical advancements in active
learning, 2) applications of active learning in computer vision, 3) industrial
systems leveraging or with potential to leverage active learning for data
iteration, 4) current limitations and future research directions. We expect
this paper to clarify the significance of active learning in a modern AI model
manufacturing process and to bring additional research attention to active
learning. By addressing data automation challenges and coping with automated
machine learning systems, active learning will facilitate democratization of AI
technologies by boosting model production at scale.
