Nuanced expressiveness, particularly through fine-grained hand and facial expressions, is pivotal for enhancing the realism and vitality of digital human representations. In this work, we focus on investigating the expressiveness of human avatars when learned from monocular RGB video; a setting that introduces new challenges in capturing and animating fine-grained details. To this end, we introduce EVA, a drivable human model that meticulously sculpts fine details based on 3D Gaussians and SMPL-X, an expressive parametric human model. Focused on enhancing expressiveness, our work makes three key contributions. First, we highlight the critical importance of aligning the SMPL-X model with RGB frames for effective avatar learning. Recognizing the limitations of current SMPL-X prediction methods for in-the-wild videos, we introduce a plug-and-play module that significantly ameliorates misalignment issues. Second, we propose a context-aware adaptive density control strategy, which is adaptively adjusting the gradient thresholds to accommodate the varied granularity across body parts. Last but not least, we develop a feedback mechanism that predicts per-pixel confidence to better guide the learning of 3D Gaussians. Extensive experiments on two benchmarks demonstrate the superiority of our framework both quantitatively and qualitatively, especially on the fine-grained hand and facial details. See the project website at \url{https://evahuman.github.io}

本研究聚焦于通过学习来自单目RGB视频的人类化身的表现力，介绍了一种可驾驶的人类模型EVA，该模型通过基于3D高斯分布和SMPL-X的精细塑造，旨在提升表现力；研究重点包括解决SMPL-X模型与RGB帧对齐的重要性、上下文感知的密度控制策略以及预测的反馈机制。在两个基准测试上进行的大量实验证明了我们的框架在定量和定性上的优越性，尤其在手部和面部细节方面。

从单目RGB视频生成富有表达力的高斯人类虚拟形象