  Recently, virtual reality, augmented reality, robotics, autonomous driving et
al attract much attention of both academic and industrial community, in which
image based camera localization is a key task. However, there has not been a
complete review on image-based camera localization. It is urgent to map this
topic to help people enter the field quickly. In this paper, an overview of
image based camera localization is presented. A new and complete kind of
classifications for image based camera localization is provided and the related
techniques are introduced. Trends for the future development are also
discussed. It will be useful to not only researchers but also engineers and
other people interested.
