沉浸式的虚拟现实体验中视觉诱发晕动症（Visually Induced Motion Sickness， VIMS）是影响虚拟现实系统发展与应用的一个重要问题。现有的基于视觉内容的评价方案大多考虑的要素不够全面，对运动信息的提取较为简单，且少有考虑时域上的突变对晕动症的影响。针对上述问题，提出了虚拟现实中视觉诱发晕动症时空多特征评价模型；基于立体全景视频中空域、时域信息来设计视觉诱发晕动症评价模型，采用更符合人眼感知的加权运动特征，并考虑了立体全景视频时域的突变信息设计了特征提取方式。所提出模型分为预处理模块、特征提取模块及时域聚合与回归模块。预处理模块用于视口提取和光流图、视差图、显著图的估计。特征提取模块包含前背景加权运动特征提取、基于变换域的视差特征提取、空间特征提取及时域突变特征提取。时域聚合后通过支持向量回归得到VIMS评价分数。实验结果表明，该模型在立体全景视频数据库SPVCD上的预测结果与平均主观意见分的皮尔逊线性相关系数为0.821、斯皮尔曼相关系数为0.790、均方根误差为0.489。该模型取得了优良的预测性能，验证了所提出特征提取模块的有效性。

Virtual reality (VR) and augmented reality (AR) are revolutionizing our lives. Near-eye displays are crucial technologies for VR and AR. Despite the rapid advances in near-eye display technologies, there are still challenges such as large field of view, high resolution, high image quality, natural free 3D effect, and compact form factor. Great efforts have been devoted to striking a balance between visual performance and device compactness. While traditional optics are nearing their limitations in addressing these challenges, ultra-thin metasurface optics, with their high light-modulating capabilities, may present a promising solution. In this review, we first introduce VR and AR near-eye displays, and then briefly explain the working principles of light-modulating metasurfaces, review recent developments in metasurface devices geared toward near-eye display applications, delved into several advanced natural 3D near-eye display technologies based on metasurfaces, and finally discuss about the remaining challenges and future perspectives associated with metasurfaces for near-eye display applications.

视觉诱导晕动症（VIMS）是虚拟现实（VR）体验过程中可能产生的一种常见症状，该症状严重降低了用户的体验的舒适度，阻碍了VR技术的推广和发展。虚拟空间畸变是影响VR体验舒适度的潜在因素之一，近眼显示设备不完全的畸变校正会产生虚拟空间畸变，进而可能引发VIMS。针对虚拟空间畸变对VIMS的影响程度，本文模拟VR技术的体验过程，对以VR技术为代表的近眼显示技术畸变机理进行分析，设计了3个不同畸变参数下VIMS等级评价的视觉感知实验，并对实验的主客观数据进行统计分析。结果表明，虚拟空间畸变对VIMS症状具有显著性影响，受测者观看立体影像的畸变程度越大，所引起的VIMS症状越明显。该研究可为VR技术体验的舒适度提升方向提供理论依据。

Augmented reality (AR) and virtual reality (VR) are two novel display technologies that are under updates. The essential feature of AR/VR is the full-color display that requires high pixel densities. To generate three-color pixels, the fluorescent color conversion layer inevitably includes green and red pixels. To fabricate such sort of display kits, inkjet printing is a promising way to position the color conversion layers. In this review article, the progress of AR/VR technologies is first reviewed, and in succession, the state of the art of inkjet printing, as well as two key issues — the optimization of ink and the reduction of coffee-ring effects, are introduced. Finally, some potential problems associated with the color converting layer are highlighted.Augmented reality (AR) and virtual reality (VR) are two novel display technologies that are under updates. The essential feature of AR/VR is the full-color display that requires high pixel densities. To generate three-color pixels, the fluorescent color conversion layer inevitably includes green and red pixels. To fabricate such sort of display kits, inkjet printing is a promising way to position the color conversion layers. In this review article, the progress of AR/VR technologies is first reviewed, and in succession, the state of the art of inkjet printing, as well as two key issues — the optimization of ink and the reduction of coffee-ring effects, are introduced. Finally, some potential problems associated with the color converting layer are highlighted.