  Unmanned aerial vehicles (UAVs) are widely used platforms to carry data
capturing sensors for various applications. The reason for this success can be
found in many aspects: the high maneuverability of the UAVs, the capability of
performing autonomous data acquisition, flying at different heights, and the
possibility to reach almost any vantage point. The selection of appropriate
viewpoints and planning the optimum trajectories of UAVs is an emerging topic
that aims at increasing the automation, efficiency and reliability of the data
capturing process to achieve a dataset with desired quality. On the other hand,
3D reconstruction using the data captured by UAVs is also attracting attention
in research and industry. This review paper investigates a wide range of
model-free and model-based algorithms for viewpoint and path planning for 3D
reconstruction of large-scale objects. The analyzed approaches are limited to
those that employ a single-UAV as a data capturing platform for outdoor 3D
reconstruction purposes. In addition to discussing the evaluation strategies,
this paper also highlights the innovations and limitations of the investigated
approaches. It concludes with a critical analysis of the existing challenges
and future research perspectives.
