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.

翻译：动态三维网格是虚拟现实应用中的关键组成部分。然而，此类内容对实时渲染需要大量处理资源。为了在保证用户体验的同时降低处理需求，现有研究提出基于观看距离调整三维网格的细节层次。本文通过开展大规模主观质量评估实验，研究细节层次与观看距离对虚拟现实环境中动态三维网格用户感知的影响。评估结果构建了一个包含320个测试刺激的主观数据集（来自八个动态三维网格），分析表明可移除网格半数面片而不引起用户体验质量（QoE）的显著下降。对现有客观质量指标的评估显示，基于二维和基于三维的指标与主观评分相关性较低。基于该主观数据集，我们提出了一种新型QoE预测模型，能够准确预测指定细节层次和观看距离下动态三维网格的平均意见得分（MOS）。此外，本文还设计并评估了一种QoE感知的资源分配框架，在不同资源约束下相比传统方法显著提升了总体QoE。