PointXR: A toolbox for visualization and subjective evaluation of point clouds in virtual reality

In this study, we explore the use of virtual reality to subjectively evaluate the visual quality of point cloud contents. To this aim, we develop the PointXR toolbox, a set of Unity applications that can host experiments under variants of interactive and passive evaluation protocols. An auxiliary tool to facilitate the configuration of the supported rendering schemes for point cloud visualization is provided as part of it. Our toolbox is employed to conduct two validating experiments in a virtual environment with 6 degrees of freedom. The purpose is to assess the performance of color encoders that are incorporated in the upcoming MPEG standard on point cloud compression. For this study, we convert a set of mesh models to point cloud contents, and form a high-quality cultural heritage repository, namely, PointXR dataset. A comparison between the adopted protocols and the codecs' performance is carried based on the ratings obtained from both experiments. Finally, interactivity patterns based on behavioral data that were recorded during the evaluations are extracted, and results are discussed. The PointXR toolbox, the PointXR dataset, and the experimental results are made publicly available.