Subjective Quality Assessment of Dynamic 3D Meshes in Virtual Reality Environment

Abstract

A dynamic 3D mesh is a key component in Virtual Reality applications. However, this type of content demands a significant processing resource for real-time rendering. To reduce processing requirements while preserving the user experience, adjusting the level of detail of 3D meshes based on viewing distance has been proposed. In this paper, we conduct an extensive subjective quality evaluation to investigate the effects of the level of detail and viewing distance on user perception of dynamic 3D meshes in a VR environment. Our evaluation results in a subjective dataset containing user ratings of 320 test stimuli generated from eight dynamic 3D meshes. Result analysis shows that it is possible to remove half of a mesh's faces without causing noticeable degradation in user Quality of Experience (QoE). An evaluation of popular objective quality metrics reveals that both 2D-based and 3D-based metrics have low correlation with subjective scores. Based on the subjective dataset, we develop a novel QoE prediction model that can accurately predict the MOS of a dynamic 3D mesh at a given level of detail and viewing distance. In addition, a QoE-aware resource allocation framework is proposed and evaluated under different resource constraints, showing significant improvement in the total QoE compared to conventional methods.

Figures (5)

• Figure 1: Snapshots of eight dynamic 3D meshes used in the subjective experiment. Each mesh is associated with animations representing object movements.
• Figure 2: Geometry (SI_Geo) and color (SI_Col) spatial information of the considered dynamic 3D meshes.
• Figure 3: MOS values and 95% Confidence Interval of test stimuli
• Figure 4: MOSs at different levels of detail across five viewing distances (a)$\sim$(e), and average across all viewing distances (f)
• Figure 5: MOS increase amount compared to the value at d=4m of all meshes.