  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/.
