A subjective visual quality assessment method of panoramic videos

Different from 2-dimensional (2D) videos, panoramic videos contain spherical viewing direction with the support of head-mounted displays, thus improving immersive and interactive visual experience. Unfortunately, to our best knowledge, there are few subjective visual quality assessment (VQA) methods for panoramic videos. In this paper, we therefore propose a subjective VQA method for assessing quality loss of impaired panoramic videos. Specifically, we first establish a database containing viewing direction data of several subjects on watching panoramic videos. Then, we find out that there exists high consistency of viewing direction on panoramic videos across different subjects. Upon this finding, we present a procedure of subjective test in measuring quality of panoramic videos by different subjects, yielding different mean opinion score (DMOS). To couple with inconsistency of viewing directions on panoramic videos, we further propose a vectorized DMOS metric. Finally, experimental results verify that our subjective VQA method, in the forms of both overall and vectorized DMOS metrics, is effective in measuring subjective quality of panoramic videos.