360Cast: Foveation-Based Wireless Soft Delivery for 360-Degree Video
360Cast: Foveation-Based Wireless Soft Delivery for 360-Degree Video
复制标题
DOI：
10.1109/icc40277.2020.9149357
复制
发表时间：
2020-06
期刊：
影响因子：
--
通讯作者：
Yujun Lu;T. Fujihashi;S. Saruwatari;Takashi Watanabe
中科院分区：
文献类型：
--
作者：
Yujun Lu;T. Fujihashi;S. Saruwatari;Takashi Watanabe
无线360度视频传输提供虚拟现实（VR）沉浸式体验，每个用户都可以自由切换他/她的观看方向。现有的无线360度视频流方案采用基于数字的压缩和传输。然而，它们在视频流量和质量方面存在许多缺点：由于无线信道不稳定而导致悬崖效应，由于360度视频的分辨率极高而导致视频流量较大，以及传输视频中的感知冗余。针对上述问题，本文提出了一种新颖的无线360度视频传输方案360Cast。 360Cast采用基于模拟的传输，包括功率分配和模拟调制，即使在时变的无线信道中也能实现良好的视频质量改善。这里，功率分配考虑了人类感知和球面投影的失真，以最大化 360 度视频播放时的人类感知质量。此外，360Cast使用动态线性回归（DLR）根据最近HMD用户的方向来预测和传输用户的视口，并且仅传输视口以减少流量。评估结果表明，与现有的模拟传输方案（即 SoftCast 和 FoveaCast）相比，通过集成视口预测、功率分配和模拟调制，所提出的 360Cast 通过 HMD 提供了更好的人类感知质量。
Wireless 360-degree video delivery provides virtual reality (VR) immersive experience where each user can freely switch his/her viewing orientation. The existing schemes of the wireless 360-degree video streaming use digital-based compression and transmission. However, they have many disadvantages in terms of video traffic and quality: cliff effect due to unstable wireless channels, large video traffic due to the extremely high resolution of the 360-degree video, and the perceptual redundancy within the transmitted video. To solve the above problems, this paper proposes a novel wireless 360-degree video transmission scheme called 360Cast. 360Cast adopts the analog-based transmission, including power allocation and analog modulation, to achieve graceful video quality improvement even in time-varying wireless channels. Here, the power allocation considers the distortion of human perception and sphere-to-plane projection to maximize the human perceptual quality at the 360-degree video playback. In addition, 360Cast predicts and transmits the user’s viewport based on the recent HMD user’s orientation by using dynamic linear regression (DLR) and only transmits the viewport for traffic reduction. Evaluation results show that the proposed 360Cast provides better human perceptual quality via HMD compared with the existing analog transmission schemes, i.e., SoftCast and FoveaCast, by using the integration of viewport prediction, power allocation, and analog modulation.