We propose OFERA, a novel framework for real-time expression control of photorealistic Gaussian head avatars for VR headset users. Existing approaches attempt to recover occluded facial expressions using additional sensors or internal cameras, but sensor-based methods increase device weight and discomfort, while camera-based methods raise privacy concerns and suffer from limited access to raw data. To overcome these limitations, we leverage the blendshape signals provided by commercial VR headsets as expression inputs. Our framework consists of three key components: (1) Blendshape Distribution Alignment (BDA), which applies linear regression to align the headset-provided blendshape distribution to a canonical input space; (2) an Expression Parameter Mapper (EPM) that maps the aligned blendshape signals into an expression parameter space for controlling Gaussian head avatars; and (3) a Mapper-integrated Avatar (MiA) that incorporates EPM into the avatar learning process to ensure distributional consistency. Furthermore, OFERA establishes an end-to-end pipeline that senses and maps expressions, updates Gaussian avatars, and renders them in real-time within VR environments. We show that EPM outperforms existing mapping methods on quantitative metrics, and we demonstrate through a user study that the full OFERA framework enhances expression fidelity while preserving avatar realism. By enabling real-time and photorealistic avatar expression control, OFERA significantly improves telepresence in VR communication. A project page is available at https://ysshwan147.github.io/projects/ofera/.

翻译：我们提出OFERA，一种面向VR头显用户的逼真高斯头部化身实时表情控制新框架。现有方法尝试使用额外传感器或内部摄像头来恢复被遮挡的面部表情，但基于传感器的方法会增加设备重量和不适感，而基于摄像头的方法则引发隐私担忧且难以获取原始数据。为克服这些限制，我们利用商用VR头显提供的混合形状信号作为表情输入。我们的框架包含三个关键组件：(1) 混合形状分布对齐(BDA)，应用线性回归将头显提供的混合形状分布对齐到规范输入空间；(2) 表情参数映射器(EPM)，将对齐后的混合形状信号映射到用于控制高斯头部化身的表情参数空间；(3) 集成映射器的化身(MiA)，将EPM融入化身学习过程以确保分布一致性。此外，OFERA建立了端到端流程，可在VR环境中实时感知与映射表情、更新高斯化身并进行渲染。我们通过量化指标证明EPM优于现有映射方法，并通过用户研究表明完整OFERA框架在保持化身真实感的同时提升了表情保真度。通过实现实时逼真的化身表情控制，OFERA显著提升了VR通信中的临场感。项目页面详见 https://ysshwan147.github.io/projects/ofera/。