  With rapid advancements in the area of mobile robotics and industrial
automation, a growing need has arisen towards accurate navigation and
localization of moving objects. Camera based motion estimation is one such
technique which is gaining huge popularity owing to its simplicity and use of
limited resources in generating motion path. In this paper, an attempt is made
to introduce this topic for beginners covering different aspects of vision
based motion estimation task. The evolution of VO schemes over last few decades
is discussed under two broad categories, that is, geometric and non-geometric
approaches. The geometric approaches are further detailed under three different
classes, that is, feature-based, appearance-based, and a hybrid of feature and
appearance based schemes. The non-geometric approach is one of the recent
paradigm shift from conventional pose estimation technique and is thus
discussed in a separate section. Towards the end, a list of different datasets
for visual odometry and allied research areas are provided for a ready
reference.
