QoE and Immersion of Dynamic Point Cloud

Point cloud streaming has recently attracted research attention as it has the potential to provide six degrees of freedom movement, which is essential for truly immersive media. The transmission of point clouds requires high-bandwidth connections, and adaptive streaming is a promising solution to cope with fluctuating bandwidth conditions. Thus, understanding the impact of different factors in adaptive streaming on the Quality of Experience (QoE) becomes fundamental. Point clouds have been evaluated in Virtual Reality (VR), where viewers are completely immersed in a virtual environment. Augmented Reality (AR) is a novel technology and has recently become popular, yet quality evaluations of point clouds in AR environments are still limited to static images. In this paper, we perform a subjective study of four impact factors on the QoE of point cloud video sequences in AR conditions, including encoding parameters (quantization parameters, QPs), quality switches, viewing distance, and content characteristics. The experimental results show that these factors significantly impact the QoE. The QoE decreases if the sequence is encoded at high QPs and/or switches to lower quality and/or is viewed at a shorter distance, and vice versa. Additionally, the results indicate that the end user is not able to distinguish the quality differences between two quality levels at a specific (high) viewing distance.This repository contains the results of the subjective test on the quality of experience (QoE) for dynamic point clouds in augmented reality environments.

点云流（Point cloud streaming）近年来备受研究关注，因其具备实现六自由度运动的潜力，而这正是实现真正沉浸式媒体体验的核心要素。点云的传输依赖高带宽连接，自适应流（adaptive streaming）则是应对带宽波动状况的极具前景的解决方案。因此，明晰自适应流中的各类因素对用户体验质量（Quality of Experience，QoE）的影响，便成为了核心研究课题。

此前点云的质量评估多开展于虚拟现实（Virtual Reality，VR）场景中，此时观看者可完全沉浸于虚拟环境之内。增强现实（Augmented Reality，AR）作为一项新兴技术，近年来愈发普及，但目前AR环境中点云的质量评估仍仅局限于静态图像范畴。

本文针对AR场景下点云视频序列的QoE开展了一项主观测试研究，共考量四类影响因素：编码参数（量化参数，quantization parameters，QPs）、质量切换、观看距离以及内容特性。实验结果表明，上述四类因素均会对QoE产生显著影响：当点云序列采用高量化参数编码、或切换至较低质量档位、或在较近距离下观看时，用户体验质量均会下降；反之则体验质量提升。此外，实验结果还显示，在特定（较高的）观看距离下，终端用户无法区分两个不同质量档位之间的画质差异。

本数据集仓库收录了增强现实环境下动态点云的用户体验质量主观测试结果。