  The Depth-Image-Based-Rendering (DIBR) is one of the main fundamental
technique to generate new views in 3D video applications, such as Multi-View
Videos (MVV), Free-Viewpoint Videos (FVV) and Virtual Reality (VR). However,
the quality assessment of DIBR-synthesized views is quite different from the
traditional 2D images/videos. In recent years, several efforts have been made
towards this topic, but there {is a lack of} detailed survey in {the}
literature. In this paper, we provide a comprehensive survey on various current
approaches for DIBR-synthesized views. The current accessible datasets of
DIBR-synthesized views are firstly reviewed{, followed} by a summary analysis
of the representative state-of-the-art objective metrics. Then, the
performances of different objective metrics are evaluated and discussed on all
available datasets. Finally, we discuss the potential challenges and suggest
possible directions for future research.
