For a long time, in reconstructing 3D human bodies from monocular images, most methods opted to simplify the task by minimizing the influence of the camera. Using a coarse focal length setting results in the reconstructed bodies not aligning well with distorted images. Ignoring camera rotation leads to an unrealistic reconstructed body pose in world space. Consequently, the application scenarios of existing methods are confined to controlled environments. When confronted with complex and diverse in-the-wild images, they struggle to achieve accurate and reasonable reconstruction in world space. To address the above issues, we propose W-HMR, which decouples global body recovery into camera calibration, local body recovery, and global body orientation correction. We design the first weak-supervised camera calibration method for body distortion, eliminating dependence on focal length labels and achieving finer mesh-image alignment. We propose a novel orientation correction module to allow the reconstructed human body to remain normal in world space. Decoupling body orientation and body pose enables our model to consider the accuracy in camera coordinate and the reasonableness in world coordinate simultaneously, expanding the range of applications. As a result, W-HMR achieves high-quality reconstruction in dual coordinate systems, particularly in challenging scenes. Codes and demos have been released on the project page https://yw0208.github.io/w-hmr/.

翻译：长期以来，在从单目图像重建三维人体时，多数方法倾向于通过最小化相机影响来简化任务。使用粗略焦距设定会导致重建人体与畸变图像对齐不佳，而忽略相机旋转则使得重建人体在世界空间中的姿态不真实。因此，现有方法的应用场景仅限于受控环境。当面对复杂多样的野外图像时，它们难以在世界空间中实现准确且合理的重建。为解决上述问题，我们提出W-HMR，该方法将全局人体恢复解耦为相机标定、局部人体恢复和全局人体方向校正。我们设计了首个针对人体畸变的弱监督相机标定方法，消除了对焦距标签的依赖，并实现了更精细的网格-图像对齐。我们提出一种新颖的方向校正模块，使重建人体在世界空间中保持正常姿态。通过解耦人体方向与人体姿态，我们的模型能够同时考虑相机坐标系下的准确性和世界坐标系下的合理性，从而扩展应用范围。最终，W-HMR在双坐标系下实现了高质量重建，尤其适用于挑战性场景。代码和演示已在项目页面https://yw0208.github.io/w-hmr/上发布。